WO2021073641A1

WO2021073641A1 - C2 fraction alkyne selective hydrogenation catalyst and preparation method

Info

Publication number: WO2021073641A1
Application number: PCT/CN2020/121915
Authority: WO
Inventors: 谭都平; 车春霞; 常晓昕; 谢元; 韩伟; 张峰; 何崇慧; 温翯; 吕龙刚; 吴伟
Original assignee: 中国石油天然气股份有限公司
Priority date: 2019-10-17
Filing date: 2020-10-19
Publication date: 2021-04-22

Abstract

An alkyne selective hydrogenation catalyst. A catalyst carrier is aluminum oxide or mainly comprises aluminum oxide, and has a bimodal pore distribution structure; the specific surface area of the catalyst is 20-50 m ²/g; the pore diameter of small pores is 15-50 nm, and the pore diameter of macro-pores is 80-500 nm; the catalyst at least contains Pd, Ni, and Cu; on the premise that the mass of the carrier is 100%, the content of Pd is 0.035-0.08%, the content of Ni is 0.5-5%, and the weight ratio of Cu/Ni is 0.1-1.0; a microemulsion is loaded with Ni, Cu, and part of Pd, and the particle size of the microemulsion is larger than the maximum pore diameter of the small pores but smaller than the maximum pore diameter of the macro-pores; the amount of Pd loaded by the microemulsion is 1/100-1/200 of the content of Ni+Cu; part of Pd is loaded by a solution. The catalyst of the present invention can be applied to a C2 fraction selective hydrogenation process, has good anti-coking performance, and can maintain good hydrogenation activity and excellent selectivity for a long period of time.

Description

Catalyst for selective hydrogenation of carbon two fraction alkyne and preparation method thereof

Technical field

The invention relates to a selective hydrogenation catalyst for alkyne of carbon two fraction and a preparation method, in particular to a selective hydrogenation catalyst for a carbon two post-hydrogenation process and a preparation method.

Background technique

The ethylene obtained by steam cracking of petroleum hydrocarbons contains 0.5% to 2.3% of acetylene by mass. When used in polymerization, acetylene in ethylene will reduce the activity of the polymerization catalyst and affect the physical properties of the polymer, so it must be removed. At present, selective hydrogenation is widely used in industry to remove acetylene from ethylene. The main catalysts used are Pd, Pt, Au and other precious metal catalysts. In order to ensure that the ethylene produced by the hydrogenation of acetylene and the original ethylene in the raw materials will not continue to be hydrogenated to produce ethane, which will cause ethylene loss, the catalyst must have a higher hydrogenation selectivity to obtain better economic benefits.

C2 post-hydrogenation and pre-hydrogenation are based on the position of the acetylene hydrogenation reactor relative to the demethanizer. The hydrogenation reactor is located before the demethanizer for pre-hydrogenation, and the hydrogenation reactor is located after the demethanizer. After hydrogenation. The advantages of the post-hydrogenation process are that there are many control methods for the hydrogenation process, it is not easy to fly, and the operation is convenient. However, the process is more complicated and requires separate hydrogen allocation. The C2 post-hydrogenation process is prone to acetylene due to the low hydrogen content in the hydrogenation material. The hydrogenation dimerization reaction produces the C4 fraction, which is further polymerized to form oligomers with a wider molecular weight, commonly known as "green oil". The green oil is adsorbed on the surface of the catalyst and further forms coking, which blocks the pores of the catalyst and prevents the reactants from diffusing to the surface of the active center of the catalyst, which leads to the decrease of the catalyst activity.

Noble metal catalysts have high activity, but green oil is easily generated during use, which causes the catalyst to coke and deactivate, which affects the stability and service life of the catalyst. Patent CN200810119385.8 discloses a non-noble metal supported selective hydrogenation catalyst and its preparation method and application, including a carrier and main active components and auxiliary active components supported on the carrier, wherein the main active group Divided into Ni, the auxiliary active component is selected from at least one of Mo, La, Ag, Bi, Cu, Nd, Cs, Ce, Zn and Zr, the main active component and the auxiliary active component are both non- It exists in a crystalline form, the average particle size is less than 10 nm, the carrier is a porous material with no oxidizing properties; and the catalyst is prepared by a microemulsification method.

US4404124 prepares a selective hydrogenation catalyst with active component shell distribution through a stepwise impregnation method, which can be applied to the selective hydrogenation of carbon two fractions to eliminate acetylene in ethylene. US5587348 uses alumina as a carrier, adds silver and palladium as a promoter, and adds fluorine chemically bonded with alkali metals to prepare a carbon two hydrogenation catalyst with excellent performance. The catalyst has the characteristics of reducing the production of green oil, improving the selectivity of ethylene, and reducing the production of oxygenated compounds.

Patent CN1736589 reports a Pd/γ-Al ₂ O ₃ selective hydrogenation catalyst prepared by a complete adsorption impregnation method. The catalyst produces a large amount of green oil during use. Patent CN200810114744.0 discloses a catalyst for selective hydrogenation of unsaturated hydrocarbons and a preparation method thereof. The catalyst uses alumina as a carrier and palladium as an active component. The impurity resistance and coking resistance of the catalyst are improved by adding rare earth, alkaline earth metals and fluorine, but the catalyst selectivity is not ideal.

The catalysts prepared by the above methods all use catalysts with a single pore size distribution. During the fixed bed reaction process, they are affected by internal diffusion, and the selectivity of the catalysts is poor. The carrier with bimodal pore distribution ensures the high activity of the catalyst, while the existence of macropores can reduce the influence of internal diffusion and improve the selectivity of the catalyst. ZL971187339 discloses a hydrogenation catalyst. The carrier is a honeycomb-type carrier with a large pore size, which effectively improves the selectivity of the catalyst. CN1129606A discloses a hydrocarbon conversion catalyst. The supported catalyst includes alumina, nickel oxide, iron oxide, etc. The catalyst includes two types of pores, one is used to increase the catalytic reaction surface, and the other is beneficial to diffusion. Patent CN101433842A discloses a hydrogenation catalyst, which is characterized in that the catalyst has a bimodal pore distribution, the maximum radius of the small pores is 2-50nm, and the maximum radius of the macropores is 100-500nm. Because the catalyst is bimodal pores Distribution, with good hydrogenation activity, but also good selectivity, and the ethylene increase is large.

In the C2 hydrogenation reaction, the formation of green oil and the coking of the catalyst are important factors affecting the service life of the catalyst. The activity, selectivity and service life of the catalyst constitute the overall performance of the catalyst. The methods listed above may provide a better way to improve the activity and selectivity of the catalyst, but it does not solve the problem of easy coking of the catalyst, or solve the problem of the catalyst. The problem of green oil and coking is easy to form, but the problem of selectivity is not solved. Although a carrier with a macroporous structure can improve selectivity, larger molecules generated by polymerization and chain extension reactions are also likely to accumulate in the macropores of the carrier, causing the catalyst to coke and deactivate, which affects the service life of the catalyst.

201310114077.7 discloses a hydrogenation catalyst, the catalyst carrier has a bimodal pore distribution, and the active components in the catalyst include Pd, Ag, and Ni, wherein Pd and Ag are located in small pores, and Ni is located in macropores.

201310114079.6 discloses a catalyst preparation method, in which the catalyst support used has a bimodal pore distribution. By preparing a W/O type microemulsion with a particle size larger than the small pores of the carrier, the microemulsion contains nickel metal salts. Because the dynamic volume of the microemulsion is larger than the small pore size, the microemulsion particles can only enter the macropores of the carrier. The solution method is used to load Pd and Ag, and the siphon effect of the small holes is stronger. Most of the Pd and Ag enter the macropores of the carrier, so Ni is mainly located in the macropores, and Pd and Ag are mainly located in the small holes.

After adopting this method, Pd/Ag and Ni are located in pore channels with different pore diameters, the green oil produced by the reaction is saturated and hydrogenated in the macropores, and the amount of coking of the catalyst is reduced.

However, the reduction temperature of Ni often reaches about 500°C. At this temperature, Pd atoms in the reduced state are easily aggregated, which greatly reduces the activity of the catalyst. It is necessary to greatly increase the amount of active components to compensate for the loss of activity, but it will cause Decline in selectivity.

Summary of the invention

The purpose of the present invention is to provide a catalyst for selective hydrogenation of alkynes and a preparation method, in particular a catalyst for selective hydrogenation of alkynes with good coking resistance and a preparation method.

To achieve the above objective, the present invention provides a catalyst for selective hydrogenation of alkynes, wherein the catalyst carrier is alumina or mainly alumina, and has a bimodal pore distribution structure, and the specific surface area of the catalyst is 20-50m ² /g ; The pore diameter of the small pores is 15-50nm, the pore diameter of the macropores is 80-500nm, the catalyst contains at least Pd, Ni, Cu, based on the mass of the carrier as 100%, the content of Pd is 0.035-0.08%, and the content of Ni is 0.5-5 %, the weight ratio of Cu to Ni is 0.1-1.0, wherein the microemulsion is loaded with Ni, Cu and part of Pd, and the particle size of the microemulsion is not lower than the maximum pore diameter of small pores and not higher than the maximum pore diameter of macropores (Preferably larger than the maximum pore diameter of the small pores and smaller than the maximum pore diameter of the macropores), the amount of Pd supported by the microemulsion is 1/100 to 1/200 of the content of Ni+Cu; part of the Pd is supported by solution.

According to a specific embodiment of the present invention, for a specific catalyst carrier, the pore diameter of the small pores and the pore diameter of the macropores are within a size range, and the particle diameter of the microemulsion is not less than (greater than) the maximum pore diameter of the small pores. And the maximum pore size of the macropores not higher (less than) means that the particle size of the microemulsion prepared when loaded is not lower than (greater than) the upper limit of the pore diameter range of a specific catalyst carrier, not higher than (less than) ) The upper limit of the pore size range of the macropores of the catalyst carrier. According to specific embodiments of the present invention, the particle size of the microemulsion may be 50-500 nm or greater than 50 nm and less than 500 nm.

According to specific embodiments of the present invention, preferably, the catalyst of the present invention further contains Ag, which is supported by a solution, and its content is 0.08 to 0.21%. The role of Ag is to form an alloy with Pd to improve the selectivity of acetylene hydrogenation.

According to specific embodiments of the present invention, preferably, the catalyst support is alumina or mainly alumina, and has a bimodal pore distribution structure. The specific surface area of the catalyst is 20-50m ² /g; wherein the pore diameter is 15- 50nm, the pore diameter of the macropore is 80-500nm, the catalyst contains at least Pd, Ag, Ni, Cu, based on the mass of the carrier as 100%, the content of Pd is 0.035-0.07%, the content of Ag is 0.08-0.21%, and the content of Ni is 0.5- 5%, the weight ratio of Cu to Ni is 0.1～1.0, of which Ni, Cu and part of Pd are loaded in a microemulsion mode, mainly distributed in the macropores of the carrier. The amount of Pd loaded by the microemulsion method is the content of Ni+Cu 1/100～1/200 of the ratio; Ag and part of Pd are supported by the solution method.

The microemulsion loading in the present invention refers to loading by the dipping method, wherein the dipping liquid is a microemulsion. The solution loading in the present invention refers to loading by the dipping method, wherein the dipping liquid is a solution. In the catalyst of the present invention, a part of Pd is supported in the form of microemulsion, and the rest of Pd is supported by impregnation, and the amount of Pd supported by the microemulsion is 1/100 to 1/200 of the content of Ni+Cu.

According to specific embodiments of the present invention, preferably, the support is alumina or mainly alumina; the Al ₂ O ₃ crystal form is theta, alpha or mixed crystal form; the alumina in the catalyst support is more than 80%.

According to the specific embodiment of the present invention, preferably, the microemulsion loading process includes: dissolving the precursor salt in water, adding an oil phase, a surfactant and a co-surfactant, and fully stirring to form a microemulsion, wherein the oil phase is alkane or For cycloalkanes, the surfactant is an ionic surfactant and/or a nonionic surfactant, and the co-surfactant is an organic alcohol.

According to the specific embodiment of the present invention, preferably, during the loading process of the microemulsion, the oil phase is C6-C8 saturated alkane or cycloalkane, preferably cyclohexane or n-hexane; the surfactant is an ionic surfactant and/ Or non-ionic surfactant, preferably non-ionic surfactant, more preferably polyethylene glycol octyl phenyl ether or cetyl trimethyl ammonium bromide; co-surfactant is C4-C6 alcohol Type, preferably n-butanol and/or n-pentanol.

In the catalyst of the present invention, the selective hydrogenation reaction of acetylene occurs in the main active center composed of Pd, Ni and Cu will be impregnated in the macropores of the carrier in the form of microemulsion, and the green oil produced by the reaction is in the composition of Cu and Ni. Saturation hydrogenation occurs on the active center.

For the hydrogenation reaction, the hydrogenation catalyst generally needs to be reduced before the catalyst is used to ensure that the active components exist in the metal state, so that the catalyst has hydrogenation activity. Because during the catalyst preparation process, activation is a high-temperature calcination process, metal salts generally decompose into metal oxides, and the oxides form clusters, which are generally nano-sized. Different oxides need to be reduced at different temperatures due to their different chemical properties. However, for nano-sized metals, a temperature of about 200°C is an important critical temperature. Above this temperature, the metal particles will aggregate significantly. Therefore, reducing the reduction temperature of the active components to below 200°C is of great significance to the hydrogenation catalyst.

The idea of solving catalyst coking in the present invention is:

The selective hydrogenation reaction of acetylene occurs in the main active center composed of Pd (when it contains Ag, it occurs in the main active center composed of Pd and Ag). The green oil and other macromolecules produced in the reaction easily enter the macropores of the catalyst. . In the macropores of the catalyst, Ni/Cu components are supported, where Ni has a saturated hydrogenation function, and the green oil component will undergo a saturated hydrogenation reaction in the active center composed of Ni/Cu. Because the double bond is saturated by hydrogenation, the green oil component can no longer undergo polymerization or the polymerization rate is greatly reduced, and its chain extension reaction is terminated or delayed, and it cannot form a large molecular weight fused ring compound, and it is easy to be carried out of the reactor by the material, so the catalyst The degree of coking on the surface of the catalyst will be greatly reduced, and the operating life of the catalyst will be greatly extended.

The carrier of the present invention is required to have a bimodal pore distribution structure, especially large pores with a pore diameter of 80-500 nm, and the pore diameter of the small pores is 15-50 nm.

The method for controlling the positioning of the Ni/Cu alloy in the macropores of the catalyst is that the Ni/Cu is loaded in the form of a microemulsion, and the particle size of the microemulsion is larger than the pore diameter of the carrier but less than the maximum pore diameter of the macropore. The nickel and copper metal salts are contained in the microemulsion, and it is difficult to enter the small-sized carrier pores due to steric resistance, so they mainly enter the large pores of the carrier.

The inventors found that after Cu and Ni are loaded together, the reduction temperature of Ni can be greatly reduced. The reason is that the reduction temperature of NiO generally reaches 450°C or more, and this temperature will cause the agglomeration of Pd, and Cu/Ni alloy will be formed after adding Cu, and its reduction temperature can be lowered by more than 100°C compared with the reduction temperature of pure Ni. Reach 350°C, thereby alleviating the agglomeration of Pd.

The inventor also found that if a part of Pd is loaded on the surface of the Ni/Cu alloy, the reduction temperature of the Ni/Cu alloy can also be greatly reduced, which can reach below 200°C, or even to 150°C.

Therefore, a better catalyst is that Pd is mainly present in the small pores of the catalyst, Ni/Cu is located in the macropores of the catalyst, and there is a part of Pd in the Ni/Cu in the macropores, especially on the surface.

A better catalyst preparation process is to load a small amount of Pd in the macropores by the microemulsion method after the Ni and Cu are loaded, and the amount of Pd loaded at this time is 1/100 to 1/200 of the content of Ni+Cu.

The present invention also provides a preparation method of the above-mentioned catalyst, and the specific preparation process includes:

(1) Dissolve the precursor salts of Ni and Cu in water, add the oil phase, surfactant and co-surfactant, fully stir to form a microemulsion, add the carrier to the prepared microemulsion and soak for 0.5 to 4 hours , The remaining liquid is filtered off, and after drying, it is calcined at 400-600°C for more than 4 hours to obtain semi-finished catalyst A;

(2) Dissolve the precursor salt of Pd in water, adjust the pH to 1.5-2.5, then add the semi-finished catalyst A to the Pd salt solution, immerse and adsorb for 0.5-4h, then dry and calcinate at 400-600℃ for 4～ 6h to obtain semi-finished catalyst B;

(3) Dissolve the Pd precursor salt in water, add the oil phase, surfactant and co-surfactant, fully stir to form a microemulsion, add the semi-finished catalyst B to the prepared microemulsion and soak for 0.5 to 4 hours, The remaining liquid is filtered off, and after drying, it is calcined at 400-600°C for more than 4 hours to obtain the desired catalyst.

In the above preparation steps, step (1) and step (2) can be interchanged, and step (3) is after step (1).

The carrier in the above step (1) is alumina or mainly alumina, and the Al ₂ O ₃ crystal form is preferably θ, α or a mixed crystal form thereof. The catalyst carrier preferably contains more than 80% alumina, and the carrier may also contain other metal oxides such as magnesium oxide and titanium oxide.

The carrier in the above step (1) may be spherical, cylindrical, clover-shaped, four-leaf clover-shaped, and the like.

The precursor salts of Ni, Cu and Pd described in the above steps (1) and (3) are soluble salts, which may be nitrate, chloride or other soluble salts.

According to specific embodiments of the present invention, preferably, the weight ratio of Cu to Ni is 0.1-1:1, and the amount of Pd supported by the emulsion method is 1/100-1/200 of the content of Ni+Cu.

According to a specific embodiment of the present invention, the catalyst may also contain Ag. The function of Ag is to form an alloy with the Pd supported in step (2) to improve the selectivity of acetylene hydrogenation. The principle is: Ag and Pd form an alloy, Ag atoms separate Pd atoms, so that the spatial distance of the adsorbed acetylene molecules is increased, and the corresponding acetylene hydrogenation reaction intermediates have a large mutual distance, and the coupling of the intermediates is not easy to occur. Thus reducing the formation of green oil.

According to specific embodiments of the present invention, preferably, the content of Ag is 0.08 to 0.21%. Ag is supported by a solution method, such as a saturated impregnation method.

The catalyst preparation process of the present invention also includes:

(1) Dissolve the precursor salts of Ni and Cu in water, add the oil phase, surfactant and co-surfactant, and stir thoroughly to form a microemulsion; add the carrier to the prepared microemulsion and soak for 0.5 to 4 hours , The remaining liquid is filtered off; after drying, it is calcined at 400-600℃ for 4-6h to obtain semi-finished catalyst A;

(2) Dissolve the precursor salt of Pd in water, adjust the pH to 1.5-2.5, then add the semi-finished catalyst A to the Pd salt solution, immerse and adsorb for 0.5-4h, then dry and calcinate at 400-600℃. ~6h to obtain semi-finished catalyst B;

(3) The loading of Ag is carried out by saturated dipping, that is, the prepared Ag salt solution is 80-110% of the saturated water absorption of the carrier, adjust the pH to 1-5, dry after dipping, and roast at 400-600℃ , To obtain semi-finished catalyst C;

(4) Dissolve the Pd precursor salt in water, add the oil phase, surfactant and co-surfactant, fully stir to form a microemulsion, add the semi-finished catalyst C to the prepared microemulsion and soak for 0.5 to 4 hours, The remaining liquid is filtered off; after drying, it is calcined at 400-600°C for 4-6 hours to obtain the required catalyst.

The surfactants in the above steps (1) and (4) are ionic surfactants or nonionic surfactants, preferably nonionic surfactants, more preferably polyethylene glycol octylphenyl ether ( Triton X-100), Cetyltrimethylammonium Bromide (CTAB).

The oil phase in the above steps (1) and (4) is C ₆ -C ₈ saturated alkane or cycloalkane, preferably cyclohexane or n-hexane.

The co-surfactants in the above steps (1) and (4) are C ₄ to C ₆ alcohols, preferably n-butanol and n-pentanol.

The reduction temperature of the catalyst of the present invention is preferably 150 to 200°C.

According to a specific embodiment of the present invention, in the preparation process of the catalyst, preferably, the step of loading Pd in the microemulsion is after the step of loading Ni and Cu in the microemulsion.

According to a specific embodiment of the present invention, in the preparation process of the catalyst, preferably, the order of the solution loading of Pd and the loading of the Ni/Cu microemulsion is not limited.

According to a specific embodiment of the present invention, in the preparation process of the catalyst, preferably, the step of supporting Ag in the solution is after the step of supporting Pd in the solution.

In order to prevent Ni and Cu from entering the small pores and covering the loaded palladium, it is best to load palladium by solution method after loading Ni+Cu by microemulsion method.

Therefore, an optimized preparation method of the optimized catalyst includes the following steps:

(2) Dissolve the Pd precursor salt in water, add the oil phase, surfactant and co-surfactant, fully stir to form a microemulsion, add the semi-finished catalyst A to the prepared microemulsion and soak for 0.5 to 4 hours. The remaining liquid is filtered off; after drying, it is calcined at 400-600°C for 4-6 hours to obtain semi-finished catalyst B;

(3) Dissolve the precursor salt of Pd in water, adjust the pH to 1.5-2.5, then add the semi-finished catalyst B to the Pd salt solution, immerse and adsorb for 0.5-4h, then dry and calcinate at 400-600℃. ~6h to obtain semi-finished catalyst C;

(4) Dissolve the Ag salt in deionization, adjust the pH to 1～5, immerse the semi-finished catalyst C in the prepared solution, dry after the solution is completely absorbed, and calcinate at 400～600℃ for 4～6h to obtain The catalyst needed.

In the present invention, the preparation conditions of the microemulsion are: the weight ratio of water phase/oil phase is 2～3, the weight ratio of surfactant/oil phase is 0.15～0.6, and the weight ratio of surfactant/co-surfactant is From 1 to 1.2, the particle size of the formed microemulsion is larger than 50 nm and smaller than 500 nm.

This catalyst has the following characteristics: at the beginning of the hydrogenation reaction, due to the high hydrogenation activity of palladium and mainly distributed in the small pores, the selective hydrogenation reaction of acetylene mainly occurs in the small pores. With the extension of the catalyst running time, some by-products with larger molecular weight are formed on the surface of the catalyst. Because of the larger molecular size, more of these substances enter the macropores and the residence time is longer. Under the action of the nickel catalyst, Hydrogenation of the double bond occurs, and saturated hydrocarbons or aromatic hydrocarbons without isolated double bonds are generated, and no larger molecular weight substances are generated.

The inventors found that the initial activity of the catalyst prepared by this method was significantly improved compared with the bimodal pore distribution catalyst without palladium.

The inventors also found that after using the catalyst, even if the reactant contains more heavy fractions, the amount of green oil produced by the catalyst is greatly increased, and the activity and selectivity of the catalyst still have no tendency to decrease.

Description of the drawings

Figure 1 shows the particle size distribution of the Ni and Cu microemulsion prepared in Example 1.

FIG. 2 is a TPR chart of the catalyst of Example 1. FIG.

Detailed ways

The following characterization methods are used in the preparation process of the catalyst of the present invention: dynamic light scattering particle size analyzer to analyze the particle size distribution of Ni/Cu alloy microemulsion on M286572 dynamic light scattering analyzer; The company's 9510 mercury porosimeter analyzes the pore volume, specific surface area and pore size distribution of the carrier. On the A240FS atomic absorption spectrometer, the content of Pd, Ag, Ni and Cu in the catalyst was measured.

The Agilent 7890A gas chromatograph measures the hydrogen and acetylene content at the outlet and inlet of the reactor.

A 0.1mg electronic balance measures the weight of the catalyst.

Example 1

Catalyst carrier: A commercially available bimodal pore distribution spherical alumina carrier with a diameter of 4mm is used. After calcination at 1092°C for 4 hours, the bimodal pore size distribution ranges from 15 to 38 nm and 80 to 350 nm, the water absorption rate is 65%, and the specific surface area is 49.65 m ² /g. Weigh 100 g of the carrier.

Catalyst preparation:

(1) Weigh 15.51g of anhydrous nickel nitrate and 1.05g of copper chloride, dissolve it in 60mL of deionized water, add 28.57g of cyclohexane, add 16.57g of Triton X-100, add 16.g of n-butanol, and stir well. Form a microemulsion (the particle size distribution data of the Ni and Cu microemulsion are shown in Table 1 and Figure 1), and immerse 100g of the high-temperature roasted carrier weighed into the prepared microemulsion, shake for 30 minutes, and filter out the remaining The solution is washed with deionized water, dried at 40°C, and calcined at 400°C for 6 hours, which is called semi-finished catalyst A1.

(2) Weigh 0.0651g of palladium nitrate, dissolve it in 110mL of deionized water, adjust the pH to 1.5, then immerse the semi-finished catalyst A1 in the prepared Pd salt solution, immerse for 30 minutes, dry at 80°C, and roast at 400°C In 6 hours, a semi-finished catalyst B1 was obtained.

(3) Weigh 0.046g of palladium chloride and dissolve it in 60mL of deionized water, add 28.57g of cyclohexane, add 16.57g of Triton X-100, add 16.57g of n-butanol, and stir well to form a microemulsion. 100g semi-finished catalyst B1 was placed in the prepared microemulsion, shaken for 30 minutes, filtered off the remaining liquid, dried at 40°C, and calcined at 400°C for 6 hours to obtain the desired catalyst.

The particle size of the microemulsion emulsion prepared in step (1) of the dynamic light scattering measurement is 60.71 nm, and the particle size of the microemulsion prepared in step (3) is 60.18 nm.

The prepared catalyst was measured by atomic absorption spectrometry, and it was obtained that in the catalyst prepared in Example 1, the content of Pd was 0.0575%, the content of Ni was 5%, and the content of Cu was 0.5%.

Table 1 Particle size distribution data of the microemulsion in Example 1

Reduction of the catalyst:

Place it in a fixed-bed reaction device before use, and use _{a mixed gas with a molar ratio of N 2} :H ₂ = 1:1 to perform reduction treatment at a temperature of 200° C. for 8 hours.

The TPR of this catalyst is shown in Figure 2. It can be seen from Figure 2 that the reduction temperature of the Ni/Cu alloy is 350°C. After adding Pd to Ni/Cu, the reduction temperature is about 150°C.

Comparative example 1

The same carrier as in Example 1 was used, and the catalyst preparation conditions were the same as in Example 1, except that Cu was not supported.

Catalyst preparation:

(1) Weigh 15.61g of anhydrous nickel nitrate and dissolve it in 60mL deionized water, add 28.57g of cyclohexane, add 16.57g of Triton X-100, add 16.g of n-butanol and stir well to form a microemulsion, weigh 100g The carrier calcined at high temperature is immersed in the prepared microemulsion, shaken for 30 minutes, filtered off the remaining liquid, dried at 40°C, and calcined at 400°C for 6 hours, which is called semi-finished catalyst A1-1.

(2) Weigh 0.0651g of palladium nitrate, dissolve it in 110mL of deionized water, adjust the pH to 1.5, and then immerse the semi-finished catalyst A1-1 in the prepared Pd salt solution. After immersing for 30 minutes, dry at 80°C for 6 hours, 400 Calcined at ℃ for 6 hours to obtain semi-finished catalyst B1-1.

(3) Weigh 0.046g of palladium chloride and dissolve it in 60mL of deionized water, add 28.57g of cyclohexane, add 16.57g of Triton X-100, add 16.g of n-butanol, and stir well to form a microemulsion. ) The prepared semi-finished catalyst B1-1 is placed in the prepared microemulsion, shaken for 30 minutes, the remaining liquid is filtered off, dried at 40°C, and calcined at 400°C for 6 hours to obtain the desired catalyst.

Dynamic light scattering measurement (1) the particle size of the microemulsion emulsion prepared is 62.12nm, and (3) the particle size of the microemulsion emulsion prepared is 60.18nm.

The prepared catalyst was measured by atomic absorption spectrometry, and in Comparative Example 1, the Pd content was 0.0575%, and the Ni content was 5%.

Reduction of the catalyst:

Place it in a fixed bed reaction device before use, and use _{a mixed gas with a molar ratio of N 2} :H ₂ = 1:1 to reduce treatment at 200°C for 8 hours.

Example 2

Carrier: A commercially available bimodal pore distribution spherical alumina carrier with a diameter of 3mm is used. After calcination at 1111°C for 4 hours, the bimodal pore size distribution ranges from 20 to 40 nm and 120 to 400 nm, the water absorption rate is 62%, and the specific surface area is 39.71 m ² /g. Weigh 100 g of the carrier.

Catalyst preparation:

(1) Weigh 1.098g of nickel chloride and 1.47g of copper nitrate, dissolve in 70mL of deionized water, add 34.14g of n-hexane, add 20.g of CATB, add 19.g of n-pentanol, stir well to form a microemulsion, weigh The 100g high-temperature roasted carrier is immersed in the prepared microemulsion, shaken for 90 minutes, the remaining liquid is filtered off, dried at 80°C, and calcined at 600°C for 4 hours, which is called semi-finished catalyst A2.

(2) Weigh 0.068g of palladium chloride, dissolve it in 100mL of deionized water, adjust the pH to 1.8, and then immerse the semi-finished catalyst A2 in the prepared Pd salt solution. After immersing for 60 minutes, dry at 100°C, and under the condition of 600°C Calcined for 4 hours to obtain semi-finished catalyst B2.

(3) Weigh 0.0167g of palladium chloride, dissolve it in 70mL of deionized water, add 34.14g of n-hexane, add 20.g of CATB, add 19.g of n-pentanol, stir well to form a microemulsion, prepare in step (2) The semi-finished catalyst B2 was immersed in the prepared microemulsion, shaken for 90 minutes, filtered off the remaining liquid, dried at 70°C, and calcined at 600°C for 4 hours to obtain the desired catalyst.

The particle size of the microemulsion prepared in step (1) of the dynamic light scattering measurement is 55.48 nm, and the particle size of the microemulsion prepared in step (3) is 54.40 nm.

The prepared catalyst was determined by atomic absorption spectrometry. In the catalyst of Example 2, the content of Pd was 0.05%, the content of Ni was 0.5%, and the content of Cu was 0.5%.

Reduction of the catalyst:

Place it in a fixed bed reaction device before use, and use _{a mixed gas with a molar ratio of N 2} :H ₂ = 1:1 to perform reduction treatment at 150° C. for 8 hours.

Comparative example 2

The same carrier as in Example 2 was used, and the catalyst preparation conditions were the same as in Example 2, except that Cu was supported by the solution method.

Carrier: A commercially available bimodal pore distribution spherical alumina carrier with a diameter of 3mm is used. After calcination at 111°C for 4 hours, the bimodal pore size distribution ranges from 20 to 40 nm and 120 to 400 nm, the water absorption rate is 62%, and the specific surface area is 39.71 m ² /g. Weigh 100 g of the carrier.

Catalyst preparation:

(1) Weigh 1.098g of nickel chloride, dissolve it in 70mL of deionized water, add 34.14g of n-hexane, add 20.g of CATB, add 19.g of n-pentanol, stir well to form a microemulsion, and weigh 100g of high temperature The calcined carrier is immersed in the prepared microemulsion, shaken for 90 minutes, the remaining liquid is filtered off, dried at 80°C, and calcined at 600°C for 4 hours, which is called semi-finished catalyst A2-1.

(2) Weigh 0.068g of palladium chloride and 1.47g of copper nitrate, dissolve them in 100mL of deionized water, adjust the pH to 1.8, and then immerse the semi-finished catalyst A2-1 in the prepared Pd salt solution. After immersing for 60 minutes, 100 It was dried at ℃ and calcined at 600 ℃ for 4 hours to obtain semi-finished catalyst B2-1.

(3) Weigh 0.0167g of palladium chloride, dissolve it in 70mL of deionized water, add 34.14g of n-hexane, add 20.g of CATB, add 19.g of n-pentanol, stir well to form a microemulsion, prepare in step (2) The semi-finished catalyst B2-1 was immersed in the prepared microemulsion, shaken for 90 minutes, filtered off the remaining liquid, dried at 70°C, and calcined at 600°C for 4 hours to obtain the desired catalyst.

The prepared catalyst was measured by atomic absorption spectrometry. In Example 2, the Pd content was 0.05%, the Ni content was 0.5%, and the Cu content was 0.5%.

Reduction of the catalyst:

Place it in a fixed bed reaction device before use, use _{a mixed gas with a molar ratio of N 2} :H ₂ =1:1, and perform a reduction treatment at a temperature of 150° C. for 8 hours.

Example 3

Carrier: A commercially available bimodal pore distribution spherical alumina carrier with a diameter of 4mm is used. After calcination at 1128°C for 4 hours, the bimodal pore size distribution ranges from 25 to 50 nm and 95 to 500 nm, the water absorption rate is 62%, and the specific surface area is 20.19 m ² /g. Weigh 100 g of the carrier.

Catalyst preparation:

(1) Weigh 6.203g of anhydrous nickel nitrate and 2.11g of copper chloride, dissolve it in 76mL of deionized water, add 26g of cyclohexane, add 4.9g of Triton X-100, add 4.49g of n-butanol, and stir well to form micro For the emulsion, immerse 100g of the carrier that has been calcined at high temperature into the prepared microemulsion, shake for 240min, filter out the remaining liquid, dry at 80°C, and calcinate at 500°C for 5h, which is called semi-finished catalyst A3.

(2) Weigh 0.108g of palladium nitrate, dissolve it in 90mL of deionized water, adjust the pH to 2, then immerse the semi-finished catalyst A3 in the prepared Pd salt solution, after immersing for 90 minutes, dry at 120°C, and roast at 500°C In 5 hours, a semi-finished catalyst B3 was obtained.

(3) Weigh 0.33g of silver nitrate, dissolve it in 68.2mL of deionized water, adjust the pH to 4, dissolve the semi-finished catalyst B3 prepared in step (2) in the prepared silver-containing silver nitrate solution, shake, After the solution is completely absorbed, it is dried at 150°C and calcined at 500°C for 5 hours to obtain a semi-finished catalyst C3.

(4) Weigh 0.043g of palladium nitrate, dissolve it in 76mL of deionized water, add 26g of cyclohexane, add 4.9g of Triton X-100, add 4.49g of n-butanol, stir well to form a microemulsion, prepare in step (3) The semi-finished catalyst C3 was immersed in the prepared microemulsion, shaken for 240 minutes, filtered off the remaining liquid, dried at 80°C, and calcined at 500°C for 5 hours to obtain the desired catalyst.

The particle size of the microemulsion prepared in step (1) of the dynamic light scattering measurement is 403.65 nm, and the particle size of the microemulsion prepared in step (4) is 401.83 nm.

The prepared catalyst was determined by atomic absorption spectrometry. In Example 3, the Pd content was 0.07%, the Ni content was 2%, the Cu content was 1%, and the Ag content was 0.21%.

Reduction of the catalyst:

Place it in a fixed bed reaction device before use, and use pure hydrogen for reduction treatment at 150°C for 8 hours.

Comparative example 3

The same carrier as in Example 3 was used, and the catalyst preparation conditions were the same as in Example 3, except that the emulsion method did not support Pd.

Catalyst preparation:

(1) Weigh 6.203g of anhydrous nickel nitrate, dissolve 2.11g of copper chloride in 76mL deionized water, add 26g of cyclohexane, add 4.9g of Triton X-100, add 4.49g of n-butanol, and stir well to form a microemulsion , Immerse the weighed 100g carrier into the prepared microemulsion, shake for 100min, filter out the remaining liquid, dry at 80°C, and calcinate at 500°C for 5h, which is called semi-finished catalyst A3-1.

(2) Weigh 0.151g of palladium nitrate, dissolve it in 90mL of deionized water, adjust the pH to 2, and then immerse the semi-finished catalyst A3-1 in the prepared Pd salt solution. After immersing for 90 minutes, dry at 120°C for 4 hours, 500 It is calcined at ℃ for 5 hours to obtain semi-finished catalyst B3-1.

(3) Weigh 0.33 g of silver nitrate, dissolve it in 68.2 mL of deionized water, adjust the pH to 4, and dissolve the semi-finished catalyst B3-1 prepared in step (2) in the prepared silver-containing silver nitrate solution. Shake, after the solution is completely absorbed, dry at 150°C for 2 hours, and calcinate at 500°C for 5 hours to obtain the desired catalyst.

The particle size of the microemulsion emulsion prepared in the dynamic light scattering measurement step (1) is 403.65 nm.

The prepared catalyst was determined by atomic absorption spectrometry. In Comparative Example 3, the Pd content was 0.07%, the Ni content was 2%, the Cu content was 1%, and the Ag content was 0.21%.

Reduction of the catalyst:

Place it in a fixed bed reaction device before use, and use pure hydrogen at 150°C for reduction treatment for 8 hours.

Example 4

Carrier: A commercially available spherical alumina-titania carrier with bimodal pore distribution is used, with a titania content of 20% and a diameter of 3mm. After calcination at 1118°C for 4 hours, the bimodal pore size distribution ranges from 23 to 47 nm and 90 to 450 nm, the water absorption rate is 58%, and the specific surface area is 30.28 m ² /g. Weigh 100 g of the carrier.

Catalyst preparation:

(1) Weigh 2.21g of nickel chloride and 2.94g of copper nitrate, dissolve in 80mL of deionized water, add 40.00g of n-hexane, add 24g of CATB, add 23g of n-pentanol, and stir well to form a microemulsion. The calcined carrier is immersed in the prepared microemulsion, shaken for 180 minutes, filtered to remove the remaining liquid, dried at 80°C, and calcined at 550°C for 5 hours, which is called semi-finished catalyst A4.

(2) Weigh 0.033g of palladium chloride, dissolve it in 80mL of deionized water, add 40.00g of n-hexane, add 24g of CATB, add 23g of n-pentanol, stir well to form a microemulsion, and impregnate the semi-finished catalyst A4 into the prepared microemulsion In the medium, shake for 180min, filter out the remaining liquid, dry at 80°C, and calcinate at 550°C for 5h, which is called semi-finished catalyst B4.

(3) Weigh 0.075g of palladium chloride, dissolve it in 80mL of deionized water, adjust the pH to 2.5, and then immerse the semi-finished catalyst B4 in the prepared Pd salt solution. After immersing for 120 minutes, dry at 130°C and 550°C. Calcined for 5 hours to obtain semi-finished catalyst C4.

(4) Weigh 0.126 g of silver nitrate, dissolve it in 58 mL of deionized water, adjust the pH to 5, dissolve the semi-finished catalyst C4 prepared in step (3) in the prepared silver-containing silver nitrate solution, shake, and wait. After the solution is completely absorbed, it is dried at 100°C and calcined at 500°C for 5 hours to obtain the desired catalyst.

The particle size of the microemulsion emulsion prepared in step (1) of the dynamic light scattering measurement is 52.83 nm, and the particle size of the microemulsion emulsion prepared in step (2) is 52.61 nm.

The prepared catalyst was determined by atomic absorption spectrometry. In Example 4, the Pd content was 0.064%, the Ni content was 1%, the Cu content was 1%, and the Ag content was 0.08%.

Reduction of the catalyst:

Comparative example 4

The carrier and preparation conditions are the same as in Example 4, except that there is no Ni in the comparative example.

(1) Weigh 2.94g copper nitrate, dissolve it in 80mL deionized water, add 40.00g n-hexane, 24g CATB, 23g n-pentanol, stir well to form a microemulsion, and immerse the weighed 100g high-temperature roasted carrier into In the prepared microemulsion, shake for 180min, filter the remaining liquid, dry at 80°C, and calcinate at 550°C for 5h, which is called semi-finished catalyst A4-1.

(2) Weigh 0.033g of palladium chloride, dissolve it in 80mL of deionized water, add 40.00g of n-hexane, add 24g of CATB, add 23g of n-pentanol, stir well to form a microemulsion, and impregnate the semi-finished catalyst A4-1 into the prepared In the microemulsion, shake for 180 minutes, filter out the remaining liquid, dry at 80°C, and calcinate at 550°C for 5 hours, which is called semi-finished catalyst B4-1.

(3) Weigh 0.075g of palladium chloride, dissolve it in 80mL of deionized water, adjust the pH to 2.5, and then immerse the semi-finished catalyst B4-1 in the prepared Pd salt solution. After immersing for 120 minutes, dry at 130°C and 500°C. Calcined under conditions for 5 hours to obtain semi-finished catalyst C4-1.

(4) Weigh 0.126 g of silver nitrate, dissolve it in 58 mL of deionized water, adjust the pH to 5, and dissolve the semi-finished catalyst N prepared in step (3) in the prepared silver-containing silver nitrate solution, shake, and wait. After the solution is completely absorbed, it is dried at 100°C and calcined at 550°C for 5 hours to obtain the desired catalyst.

The particle size of the microemulsion emulsion prepared in step (1) of the dynamic light scattering measurement is 52.87 nm, and the particle size of the microemulsion emulsion prepared in step (2) is 52.65 nm.

The prepared catalyst was determined by atomic absorption spectrometry. In Comparative Example 4, the Pd content was 0.064%, the Cu content was 1%, and the Ag content was 0.08%.

Reduction of the catalyst:

Example 5

Carrier: A commercially available spherical alumina-magnesia carrier with bimodal pore distribution is used, the magnesium oxide content is 3%, and the diameter is 3mm. After calcination at 999°C for 4 hours, the bimodal pore size distribution ranges from 23 to 47 nm and 80 to 380 nm, the water absorption rate is 58%, and the specific surface area is 45.08 m ² /g. Weigh 100 g of the carrier.

Catalyst preparation:

(1) Weigh 0.076 g of palladium chloride, dissolve it in 80 mL of deionized water, adjust the pH to 2, then immerse the carrier in the prepared Pd salt solution, immerse for 120 minutes, dry at 130°C, and roast at 500°C for 4 Within hours, a semi-finished catalyst A5 was obtained.

(2) Weigh 0.158 g of silver nitrate, dissolve it in 58 mL of deionized water, adjust the pH to 5, and dissolve the semi-finished catalyst A5 prepared in step (1) in the prepared silver-containing silver nitrate solution, shake, and wait. After the solution is completely absorbed, it is dried at 100°C and calcined at 500°C for 4 hours to obtain a semi-finished catalyst B5.

(3) Weigh 3.295g of nickel chloride and 1.45g of copper nitrate, dissolve in 80mL of deionized water, add 35.00g of n-hexane, add 20.36.00g of Triton X-100, add 19.39g of n-hexanol, and stir well to form a microemulsion. The semi-finished catalyst B5 prepared in step (2) is immersed in the prepared microemulsion, shaken for 180 minutes, the remaining liquid is filtered off, dried at 70°C, and calcined at 500°C for 4 hours, which is called the semi-finished catalyst C5.

(4) Weigh 0.017g of palladium chloride, dissolve it in 80mL of deionized water, add 35.00g of n-hexane, add 20.36.00g of Triton X-100, add 19.39g of n-hexanol in 80mL of deionized water, stir well to form a microemulsion, and prepare The semi-finished catalyst C5 was immersed in the prepared microemulsion, shaken for 180 minutes, filtered off the remaining liquid, dried at 70°C, and calcined at 500°C for 4 hours to obtain the desired catalyst.

The particle size of the microemulsion emulsion prepared in step (3) of the dynamic light scattering measurement is 66.38 nm, and the particle size of the microemulsion emulsion prepared in step (4) is 65.22 nm.

The prepared catalyst was determined by atomic absorption spectrometry. In Example 5, the Pd content was 0.055%, the Ni content was 1.5%, the Cu content was 0.5%, and the Ag content was 0.10%.

Reduction of the catalyst:

Place it in a fixed bed reaction device before use, use _{a mixed gas with a molar ratio of N 2} :H ₂ =1:1, and perform a reduction treatment at a temperature of 180° C. for 8 hours.

Comparative example 5

The catalyst support and preparation conditions are the same as in Example 5, except that the amount of Ni added is reduced to 0.3%.

Catalyst preparation:

(1) Weigh 0.076 g of palladium chloride, dissolve it in 80 mL of deionized water, adjust the pH to 2, then immerse the carrier in the prepared Pd salt solution, immerse for 120 minutes, dry at 130°C, and roast at 500°C for 4 Within hours, a semi-finished catalyst A5-1 was obtained.

(2) Weigh 0.157 g of silver nitrate, dissolve it in 58 mL of deionized water, adjust the pH to 5, and dissolve the semi-finished catalyst A5-1 prepared in step (1) in the prepared silver-containing silver nitrate solution, and shake After the solution is completely absorbed, it is dried at 100°C and calcined at 500°C for 4 hours to obtain semi-finished catalyst B5-1.

(3) Weigh 0.659g of nickel chloride and 1.45g of copper nitrate, dissolve it in 80mL of deionized water, add 35.00g of n-hexane, add 20.36.00g of Triton X-100, add 19.39g of n-hexanol, and stir well to form a microemulsion. The semi-finished catalyst B5-1 prepared in step (2) is immersed in the prepared microemulsion, shaken for 180 minutes, the remaining liquid is filtered off, dried at 70°C, and calcined at 500°C for 4 hours, which is called the semi-finished catalyst C5-1.

(4) Weigh 0.017g of palladium chloride, dissolve it in 80mL of deionized water, add 35.00g of n-hexane, add 20.36.00g of Triton X-100, add 19.39g of n-hexanol in 80mL of deionized water, stir well to form a microemulsion, and prepare The semi-finished catalyst C5-1 was immersed in the prepared microemulsion, shaken for 180 minutes, filtered off the remaining liquid, dried at 70°C, and calcined at 500°C for 4 hours to obtain the desired catalyst.

The particle size of the microemulsion emulsion prepared in (3) was 66.32nm, and the particle size of the microemulsion emulsion prepared in (4) was 65.24nm.

The prepared catalyst was determined by atomic absorption spectrometry. In Comparative Example 5, the Pd content was 0.055%, the Ni content was 0.28%, the Cu content was 0.5%, and the Ag content was 0.10%.

Example 6

Carrier: A commercially available spherical alumina-magnesia carrier with bimodal pore distribution is used, with a magnesium oxide content of 10% and a diameter of 3mm. After calcination at 999°C for 4 hours, the bimodal pore size distribution ranges from 23 to 47 nm and 80 to 380 nm, the water absorption rate is 58%, and the specific surface area is 45.08 m ² /g. Weigh 100 g of the carrier.

Catalyst preparation:

(1) Weigh 2.20g of nickel chloride and 2.93g of copper nitrate, dissolve in 80mL of deionized water, add 36.00g of n-hexane, add 20.36.00g of Triton X-100, add 19.50g of n-hexanol, and stir well to form a microemulsion. The weighed 100g high-temperature roasted carrier was immersed in the prepared microemulsion, shaken for 180min, filtered off the remaining liquid, dried at 70°C, and calcined at 600°C for 4h, which was called semi-finished catalyst A6.

(2) Weigh 0.076g of palladium chloride, dissolve it in 80mL of deionized water, adjust the pH to 2.5, and then immerse the semi-finished catalyst A6 in the prepared Pd salt solution. After immersing for 120 minutes, dry at 130°C at 600°C. Calcined for 4 hours to obtain semi-finished catalyst B6.

(3) Weigh 0.157g of silver nitrate, dissolve it in 58mL of deionized water, adjust the pH to 5, dissolve the semi-finished catalyst B6 prepared in step (2) in the prepared silver-containing silver nitrate solution, shake it, and wait. After the solution is completely absorbed, it is dried at 100°C and calcined at 550°C for 6 hours to obtain a semi-finished catalyst C6.

(4) Weigh 0.017g of palladium chloride, dissolve it in 80mL of deionized water, add 36.00g of n-hexane, add 20.36.00g of Triton X-100, add 19.g of n-hexanol, stir well to form a microemulsion, add step (3) ) The prepared semi-finished catalyst C6 was immersed in the prepared microemulsion, shaken for 180 minutes, filtered off the remaining liquid, dried at 70°C, and calcined at 400°C for 6 hours to obtain the desired catalyst. The particle size of the microemulsion emulsion prepared in step (3) of the dynamic light scattering measurement is 66.32 nm, and the particle size of the microemulsion emulsion prepared in step (4) is 65.36 nm.

The prepared catalyst was determined by atomic absorption spectrometry. In Example 6, the Pd content was 0.055%, the Ni content was 1%, the Cu content was 1%, and the Ag content was 0.10%.

Reduction of the catalyst:

Comparative example 6

The catalyst carrier and the preparation conditions are the same as in Example 6, except that the amount of Pd added when preparing the microemulsion in step (4) is reduced to 1/3 of that of Example 6, which is less than 1/200 of the content of Ni+Cu.

Carrier: A commercially available spherical alumina-magnesia carrier with bimodal pore distribution is used, with a magnesium oxide content of 10% and a diameter of 3mm. After calcination at 1000°C for 4 hours, the bimodal pore size distribution ranges from 23 to 47 nm and 80 to 380 nm, the water absorption rate is 58%, and the specific surface area is 45.08 m ² /g. Weigh 100 g of the carrier.

Catalyst preparation:

(1) Weigh 2.20g of nickel chloride and 2.93g of copper nitrate, dissolve in 80mL of deionized water, add 36.00g of n-hexane, add 20.36.00g of Triton X-100, add 19.50g of n-hexanol, and stir well to form a microemulsion. The weighed 100g high-temperature roasted carrier was immersed in the prepared microemulsion, shaken for 180min, filtered off the remaining liquid, dried at 70°C, and calcined at 600°C for 4h, which was called semi-finished catalyst A6-1.

(2) Weigh 0.076g of palladium chloride, dissolve it in 80mL of deionized water, adjust the pH to 2.5, and then immerse the semi-finished catalyst A6-1 in the prepared Pd salt solution. After immersing for 120 minutes, dry at 130°C and 600°C. Calcined under conditions for 4 hours to obtain semi-finished catalyst B6-1.

(3) Weigh 0.157 g of silver nitrate, dissolve it in 58 mL of deionized water, adjust the pH to 5, dissolve the semi-finished catalyst B6-1 prepared in step (2) in the prepared silver-containing silver nitrate solution, and shake After the solution is fully absorbed, it is dried at 100°C and calcined at 550°C for 6 hours to obtain a semi-finished catalyst C6-1.

(4) Weigh 0.0057g of palladium chloride, dissolve it in 80mL of deionized water, add 36.00g of n-hexane, add 20.36.00g of Triton X-100, add 19.g of n-hexanol, stir well to form a microemulsion, add step (3) ) The prepared semi-finished catalyst C6-1 was immersed in the prepared microemulsion, shaken for 180 minutes, filtered off the remaining liquid, dried at 70°C, and calcined at 400°C for 6 hours to obtain the desired catalyst.

The particle size of the microemulsion emulsion prepared in step (3) of the dynamic light scattering measurement is 66.32 nm, and the particle size of the microemulsion emulsion prepared in step (4) is 65.36 nm.

The prepared catalyst was determined by atomic absorption spectrometry. In Comparative Example 6, the Pd content was 0.0483%, the Ni content was 1%, the Cu content was 1%, and the Ag content was 0.10%.

Example 7

Carrier: A commercially available spherical carrier with bimodal pore distribution is used, with 97% alumina, 3% titania, and a diameter of 3mm. After calcination at 978°C for 4 hours, the bimodal pore size distribution ranges from 20 to 35 nm and 90 to 200 nm, the water absorption rate is 62%, and the specific surface area is 49.81 m ² /g. Weigh 100 g of the carrier.

Catalyst preparation:

(1) Weigh 0.05 g of palladium chloride, dissolve it in 100 mL of deionized water, adjust the pH to 1.8, and then immerse the carrier in the prepared Pd salt solution. After immersing for 60 minutes, dry at 100°C and roast at 400°C. Within hours, a semi-finished catalyst A7 was obtained.

(2) Weigh 0.126g of silver nitrate, dissolve it in 57mL of deionized water, adjust the pH to 3, dissolve the semi-finished catalyst A7 prepared in step (1) in the prepared silver-containing silver nitrate solution, shake it, and wait. After the solution is completely absorbed, it is dried at 140°C and calcined at 600°C for 6 hours to obtain a semi-finished catalyst B7.

(3) Weigh 1.56g nickel nitrate and 1.06g copper chloride, dissolve in 71.5g water, add 27.0g n-hexane, 13.75g CTAB, 12.73g n-pentanol and fully stir to form a microemulsion, add semi-finished catalyst B7 to the preparation After immersing in a good microemulsion for 80 minutes, filter out the remaining liquid, and use deionized water lotion to make it neutral. It was dried at 80°C and calcined at 600°C for 4h to obtain a semi-finished catalyst C7.

(4) Weigh 0.009g of palladium chloride, dissolve it in 71.5g of water, add 27.50g of n-hexane, 13.75g of CTAB, and 12.50g of n-pentanol to fully stir to form a microemulsion, and add the semi-finished catalyst C7 to the prepared microemulsion After immersing for 80 minutes, filter out the remaining liquid, and use deionized water lotion to make it neutral. It was dried at 80°C and calcined at 600°C for 4 hours to obtain the desired catalyst.

The particle size of the microemulsion emulsion prepared in step (3) of the dynamic light scattering measurement is 100.60 nm, and the particle size of the microemulsion emulsion prepared in step (4) is 100.28 nm.

The prepared catalyst was determined by atomic absorption spectrometry. In Example 7, the Pd content was 0.035%, the Ni content was 0.5%, the Cu content was 0.5%, and the Ag content was 0.08%.

Reduction of the catalyst:

Place it in a fixed-bed reaction device before use, use a mixed gas with a molar ratio of N2:H2=1:1, and perform a reduction treatment at a temperature of 150°C for 8 hours.

Comparative example 7

The carrier adopts the same commercially available spherical carrier with bimodal pore distribution as in Example 7, with 97% alumina and 3% titania. It is calcined at 940°C. The bimodal pore size distribution range of the carrier is 10-20nm and 30-97nm. Water absorption 65%, the specific surface area is 75.21m ² /g. Weigh 100 g of the carrier.

Catalyst preparation:

(1) Weigh 0.05 g of palladium chloride, dissolve it in 100 mL of deionized water, adjust the pH to 1.8, and then immerse the carrier in the prepared Pd salt solution. After immersing for 60 minutes, dry at 100°C and roast at 400°C. Within hours, a semi-finished catalyst A7-1 was obtained.

(2) Weigh 0.126 g of silver nitrate, dissolve it in 57 mL of deionized water, adjust the pH to 3, dissolve the semi-finished catalyst A7-1 prepared in step (1) in the prepared silver nitrate solution containing silver, and shake After the solution is completely absorbed, it is dried at 140°C and calcined at 600°C for 6 hours to obtain a semi-finished catalyst B7-1.

(3) Weigh 1.56g of nickel nitrate and 1.06g of copper chloride, dissolve in 71.5g of water, add 27.0g of n-hexane, 13.75g of CTAB, and 12.73g of n-pentanol to fully stir to form a microemulsion, add the semi-finished catalyst B7-1 After immersing in the prepared microemulsion for 80 minutes, filter out the remaining liquid, and use deionized water lotion to make it neutral. It was dried at 80°C and calcined at 600°C for 4 hours to obtain a semi-finished catalyst C7-1.

(4) Weigh 0.009g of palladium chloride, dissolve it in 71.5g of water, add 27.5g of n-hexane, 13.75g of CTAB, and 12.50g of n-pentanol to fully stir to form a microemulsion, and add the semi-finished catalyst C7-1 to the prepared microemulsion. After immersing in the emulsion for 80 minutes, filter out the remaining liquid, and use deionized water lotion to make it neutral. It was dried at 80°C and calcined at 600°C for 4 hours to obtain the desired catalyst.

The particle size of the microemulsion emulsion prepared in step (3) of the dynamic light scattering measurement is 100.60 nm, and the particle size of the microemulsion emulsion prepared in step (4) is 100.23 nm.

The prepared catalyst was determined by atomic absorption spectrometry. In Comparative Example 7, the Pd content was 0.035%, the Ni content was 0.5%, the Cu content was 0.5%, and the Ag content was 0.08%.

Reduction of the catalyst: Place it in a fixed-bed reaction device before use, and use a mixed gas with a molar ratio of N2:H2=1:1 at a temperature of 150°C for a reduction treatment for 8 hours.

Example 8

The carrier of Example 8 is the same as that of Example 7, and the preparation conditions are the same. The difference is that the order of steps (1) and (2) is reversed.

Catalyst preparation:

(1) Weigh 0.126g of silver nitrate, dissolve it in 57mL of deionized water, adjust the pH to 3, dissolve 100g of the calcined carrier in the prepared silver-containing silver nitrate solution, shake it, and wait until the solution is completely absorbed , Dried at 140°C and calcined at 400°C for 6 hours to obtain semi-finished catalyst A8.

(2) Weigh 0.05 g of palladium chloride, dissolve it in 100 mL of deionized water, adjust the pH to 1.8, and then immerse the semi-finished catalyst A8 carrier prepared in step (1) in the prepared Pd salt solution. After immersing for 60 minutes, 100 It was dried at ℃ and calcined at 600 ℃ for 6 hours to obtain semi-finished catalyst B8.

(3) Weigh 1.56g of nickel nitrate and 1.06g of copper chloride, dissolve in 71.5g of water, add 27.0g of n-hexane, 13.75g of CTAB, and 12.73g of n-pentanol to fully stir to form a microemulsion, and prepare a semi-finished product in step (2) Catalyst B8 was immersed in the prepared microemulsion, shaken for 90 minutes, filtered off the remaining liquid, dried at 80°C, and calcined at 600°C for 4 hours, which was called semi-finished catalyst C8.

(4) Weigh 0.009g of palladium chloride, dissolve it in 71.5g of water, add 27.5g of n-hexane, 13.75g of CTAB, and 12.45g of n-pentanol to fully stir to form a microemulsion, and impregnate the semi-finished catalyst C8 prepared in (3) into the In the prepared microemulsion, shake for 90 minutes, filter out the remaining liquid, dry at 80°C, and calcinate at 600°C for 4 hours to obtain the desired catalyst.

The prepared catalyst was determined by atomic absorption spectrometry. In Example 8, the Pd content was 0.035%, the Ni content was 0.5%, the Cu content was 0.5%, and the Ag content was 0.08%.

Reduction of the catalyst:

Comparative example 8

Steps 1-3 of the catalyst support and preparation conditions are the same as in Example 8, except that the particle size of the microemulsion prepared in step (4) is larger than the maximum pore size of the support.

Carrier: A commercially available spherical carrier with bimodal pore distribution is used, with 97% alumina, 3% titania, and a diameter of 3mm. After calcination at 980°C for 4 hours, the bimodal pore size distribution ranges from 20 to 35 nm and 90 to 200 nm, the water absorption rate is 62%, and the specific surface area is 49.81 m ² /g. Weigh 100 g of the carrier.

Catalyst preparation:

(1) Weigh 0.126g of silver nitrate, dissolve it in 57mL of deionized water, adjust the pH to 3, dissolve 100g of the calcined carrier in the prepared silver-containing silver nitrate solution, shake it, and wait until the solution is completely absorbed , Dried at 140°C and calcined at 400°C for 6 hours to obtain semi-finished catalyst A8-1.

(2) Weigh 0.05 g of palladium chloride, dissolve it in 100 mL of deionized water, adjust the pH to 1.8, and then immerse the semi-finished catalyst A8-1 carrier prepared in step (1) into the prepared Pd salt solution. After immersing for 60 minutes , Dried at 100°C and calcined at 600°C for 6 hours to obtain semi-finished catalyst B8-1.

(3) Weigh 1.56g of nickel nitrate and 1.06g of copper chloride, dissolve it in 71.5g of water, add 27.10g of n-hexane, 13.75g CTAB, and 12.73g of n-pentanol to form a microemulsion and prepare a semi-finished product in step (2) The catalyst B8-1 was immersed in the prepared microemulsion, shaken for 90 minutes, filtered off the remaining liquid, dried at 80°C, and calcined at 600°C for 4 hours, which was called semi-finished catalyst C8-1.

(4) Weigh 0.009g of palladium chloride, dissolve it in 65g of water, add 22.26g of cyclohexane, 4.22g of TritonX-100, and 3.70g of n-butanol to fully stir to form a microemulsion. The semi-finished catalyst C8- prepared in (3) 1. Dip into the prepared microemulsion, shake for 90 minutes, filter out the remaining liquid, dry at 80°C, and calcinate at 600°C for 4 hours to obtain the desired catalyst.

The particle size of the microemulsion emulsion prepared in step (3) of the dynamic light scattering measurement is 100.60 nm, and the particle size of the microemulsion emulsion prepared in step (4) is 398.76 nm.

The prepared catalyst was determined by atomic absorption spectrometry. In Comparative Example 8, the Pd content was 0.031%, the Ni content was 0.5%, the Cu content was 0.5%, and the Ag content was 0.08%.

Example 9

Catalyst preparation:

Weigh a commercially available bimodal pore distribution spherical alumina carrier with a diameter of 4 mm. After being calcined at 1115°C for 4 hours, the pore size distribution ranges are respectively 28-48 nm and 102-499 nm, the water absorption is 50.35%, and the specific surface area is 20.73 m ² /g. Weigh 100 g of the carrier.

(1) Weigh 0.068g of palladium chloride salt and dissolve it in 120mL of deionized water, adjust the pH to 2.5, then add the carrier to the Pd salt solution, immerse and adsorb for 1 hour, dry at 120°C, and roast at 600°C for 4 hours. The desired semi-finished catalyst A9 is obtained.

(2) Take 50 mL of deionized water, add 0.33 g of silver nitrate to completely dissolve it, adjust the pH to 3, immerse the semi-finished catalyst A9 in the prepared solution, shake for 15 minutes, dry at 120°C, and calcinate at 600°C for 4 hours. A semi-finished catalyst B9 was prepared.

(3) Weigh 15.58g of anhydrous nickel nitrate, and dissolve 1.471g of copper nitrate in 65g of water, add 22.40g of cyclohexane, 4.25g of TritonX-100, and 3.80g of n-butanol to fully stir to form a microemulsion. The semi-finished catalyst B9 prepared in step (2) is added to the prepared microemulsion and immersed for 4 hours, the remaining liquid is filtered off, dried at 60°C, and calcined at 600°C for 4 hours to obtain a semi-finished catalyst C9.

(4) Weigh 0.059 g of palladium nitrate, dissolve it in 65 g of water, add 22.40 g of cyclohexane, 4.25 g of Triton X-100, and 3.80 g of n-butanol to fully stir to form a microemulsion. The semi-finished product C9 prepared in step (3) is immersed in the prepared microemulsion for 4 hours, the remaining liquid is filtered off, and washed with deionized water to neutrality. It was dried at 60°C and calcined at 600°C for 4 hours to obtain the desired catalyst.

The particle size of the microemulsion prepared in step (3) was determined to be 398.56 nm by the dynamic light scattering method, and the particle size of the microemulsion prepared in step (4) was 398.75 nm.

The element content was determined by atomic absorption spectrometry to obtain the catalyst prepared in Example 9. The Pd content was 0.0675%, the Ni content was 5%, the Cu content was 0.5%, and the Ag content was 0.21%.

Reduction of the catalyst:

Reducing gas: hydrogen, reducing space velocity: 100h ^-1 , temperature 150℃, keeping for 8h.

Comparative example 9

Catalyst preparation:

Using the same carrier as in Example 9, the preparation of Comparative Example 9 is the same as in Example 9, except that the particle size of the microemulsion when Ni/Cu is loaded is 622.38nm.

(1) Weigh 0.068g of palladium chloride salt and dissolve it in 120mL of deionized water, adjust the pH to 2.5, then add the carrier to the Pd salt solution, immerse and absorb for 70 minutes, dry at 120°C, and roast at 600°C for 4 hours to obtain The required semi-finished catalyst A9-1.

(2) Take 50 mL of deionized water, add 0.33 g of silver nitrate to completely dissolve it, adjust the pH to 3, immerse the semi-finished catalyst A9-1 in the prepared solution, shake for 15 minutes, dry at 120°C, and roast at 600°C. 4 Within hours, semi-finished catalyst B9-1 was prepared.

(3) Weigh 15.58g of anhydrous nickel nitrate, and dissolve 1.471g of copper nitrate in 65g of water, add 22.40g of cyclohexane, 2.75g of TritonX-100, and 2.75g of n-butanol to fully stir to form a microemulsion. The semi-finished catalyst B9-1 was added to the prepared microemulsion and immersed for 4 hours, the remaining liquid was filtered off, dried at 60°C, and calcined at 600°C for 4 hours to obtain the semi-finished catalyst C9-1.

(4) Weigh 0.059 g of palladium nitrate, dissolve it in 65 g of water, add 22.26 g of cyclohexane, 4.25 g of Triton X-100, and 3.80 g of n-butanol, and stir well to form a microemulsion. The semi-finished product C9-1 prepared in step (3) is immersed in the prepared microemulsion for 4 hours, the remaining liquid is filtered off, dried at 60°C, and calcined at 600°C for 4 hours. Get the desired catalyst.

The particle size of the prepared microemulsion obtained in step (3) was determined by the dynamic light scattering method as 621.67 nm, and the particle size of the prepared microemulsion obtained in step (4) was 399.62 nm.

The element content was determined by atomic absorption spectrometry, and the catalyst prepared in Comparative Example 9 was obtained, in which the Pd content was 0.0675%, the Ni content was 1.34%, the Cu content was 0.12%, and the Ag content was 0.21%.

Reduction of the catalyst:

Example 10

Catalyst preparation: The carrier adopts a commercially available bimodal pore distribution spherical alumina carrier with a diameter of 3mm. After calcination at 1118°C for 4 hours, the bimodal pore size distribution ranges from 30 to 43 nm and 100 to 498 nm, the water absorption rate is 62%, and the specific surface area is 20.35 m ² /g. Weigh 100 g of the carrier.

(1) Weigh 5.52g of nickel chloride, 7.38g of copper nitrate, and dissolve it in 69mL of deionized water, add 23.2g of n-pentane, add 3.45g of CATB, add 2.88g of n-octanol, and stir well to form a microemulsion. The 100g high-temperature roasted carrier was immersed in the prepared microemulsion, shaken for 90 minutes, the remaining liquid was filtered off, dried at 60°C, and calcined at 400°C for 6 hours to obtain a semi-finished catalyst A10.

(2) Weigh 0.051g of palladium chloride, dissolve it in 69mL of deionized water, add 23.2g of n-pentane, add CATB 3.50g, add 2.91g of n-octanol, stir well to form a microemulsion, and immerse the semi-finished catalyst A10 in all In the prepared microemulsion, shake for 90 minutes, filter out the remaining liquid, dry at 70°C, and calcinate at 400°C for 6 hours, which is called semi-finished catalyst B10.

(3) Weigh 0.084g of palladium chloride, dissolve it in 100mL of deionized water, adjust the pH to 1.8, and then immerse the semi-finished catalyst B10 in the prepared Pd salt solution. After immersing for 60 minutes, dry at 100°C under 400°C Calcined for 6 hours to obtain semi-finished catalyst C10.

(4) Weigh 0.158g of silver nitrate, dissolve it in 57mL of deionized water, adjust the pH to 3, dissolve the semi-finished catalyst C10 prepared in step (3) in the prepared silver-containing silver nitrate solution, shake it, and wait. After the solution is completely absorbed, it is dried at 140°C and calcined at 500°C for 6 hours to obtain the desired catalyst.

The particle size of the microemulsion emulsion prepared in step (1) of the dynamic light scattering measurement is 497.65 nm, and the particle size of the microemulsion emulsion prepared in step (2) is 495.32 nm.

The prepared catalyst was determined by atomic absorption spectrometry. In Example 10, the Pd content was 0.08%, the Ni content was 2.5%, the Cu content was 2.5%, and the Ag content was 0.10%.

Reduction of the catalyst:

Reducing gas: hydrogen, reducing space velocity: 100h ^-1 , temperature 200℃, keeping for 4h.

Comparative example 10

The preparation conditions of the catalyst are the same as in Example 10, except that the specific surface area is less than 20 m ² /g.

Catalyst preparation: The carrier adopts a commercially available bimodal pore distribution spherical alumina carrier with a diameter of 3mm. After calcination at 1155°C for 4 hours, the bimodal pore size distribution ranges from 41 to 76 nm and 114 to 684 nm, the water absorption rate is 60%, and the specific surface area is 14.29 m ² /g. Weigh 100 g of the carrier.

(1) Weigh 5.52g of nickel chloride, 7.38g of copper nitrate, and dissolve it in 69mL of deionized water, add 23.2g of n-pentane, add 3.45g of CATB, add 2.88g of n-octanol, and stir well to form a microemulsion. The 100g high-temperature roasted carrier was immersed in the prepared microemulsion, shaken for 90 minutes, the remaining liquid was filtered off, dried at 60°C, and calcined at 400°C for 6 hours to obtain a semi-finished catalyst A10-1.

(2) Weigh 0.051g of palladium chloride, dissolve it in 69mL of deionized water, add 23g of n-pentane, add CATB 3.50g, add 2.91g of n-octanol, stir well to form a microemulsion, and immerse the semi-finished catalyst A10-1 in In the prepared microemulsion, shake for 90 minutes, filter out the remaining liquid, dry at 70°C, and calcinate at 400°C for 6 hours, which is called semi-finished catalyst B10-1.

(3) Weigh 0.084g of palladium chloride, dissolve it in 100mL of deionized water, adjust the pH to 1.8, and then immerse the semi-finished catalyst B10-1 in the prepared Pd salt solution. After immersing for 60 minutes, dry at 100°C and 400°C. Calcined under conditions for 6 hours to obtain semi-finished catalyst C10-1.

(4) Weigh 0.158g of silver nitrate, dissolve it in 57mL of deionized water, adjust the pH to 3, dissolve the semi-finished catalyst C10-1 prepared in step (3) in the prepared silver-containing silver nitrate solution, and shake After the solution is completely absorbed, it is dried at 140°C and calcined at 500°C for 6 hours to obtain the desired catalyst.

The particle size of the microemulsion emulsion prepared in step (1) of the dynamic light scattering measurement is 497.61 nm, and the particle size of the microemulsion emulsion prepared in step (2) is 495.33 nm.

The prepared catalyst was determined by atomic absorption spectrometry. In Comparative Example 10, the Pd content was 0.08%, the Ni content was 2.5%, the Cu content was 2.5%, and the Ag content was 0.10%.

Reduction of the catalyst:

Example 11

Carrier: A commercially available bimodal pore distribution spherical alumina carrier with a diameter of 3mm is used. After calcination at 1100°C for 4 hours, the bimodal pore size distribution ranges from 30 to 45 nm and 300 to 450 nm, the water absorption rate is 62%, and the specific surface area is 47 m ² /g. Weigh 100 g of the carrier.

Catalyst preparation:

(1) Weigh 1.10g of nickel chloride and 1.47g of copper nitrate, dissolve it in 70mL of deionized water, add 35g of n-hexane, add 21g of CATB, add 20g of n-pentanol, and stir well to form a microemulsion. The calcined carrier is immersed in the prepared microemulsion, shaken for 90 minutes, filtered off the remaining liquid, dried at 80°C, and calcined at 500°C for 5 hours, which is called semi-finished catalyst A11.

(2) Weigh 0.067g of palladium chloride, dissolve it in 100mL of deionized water, adjust the pH to 1.8, and then immerse the semi-finished catalyst A11 in the prepared Pd salt solution. After immersing for 60 minutes, dry at 100°C, and under the condition of 500°C It is calcined for 5 hours to obtain a semi-finished catalyst B11.

(3) Weigh 0.126 g of silver nitrate, dissolve it in 57 mL of deionized water, adjust the pH to 3, and dissolve the semi-finished catalyst B11 prepared in step (2) in the prepared silver-containing silver nitrate solution, shake it, and wait. After the solution is completely absorbed, it is dried at 140°C and calcined at 500°C for 5 hours to obtain a semi-finished catalyst C11.

(4) Weigh 0.018g of palladium chloride, dissolve it in 70mL of deionized water, add 35g of n-hexane, add 21g of CATB, add 20g of n-pentanol, stir well to form a microemulsion, and immerse the weighed semi-finished catalyst C11 into the prepared In the microemulsion, shake for 90 minutes, filter out the remaining liquid, dry at 80°C, and calcinate at 500°C for 5 hours to obtain the desired catalyst.

The particle size of the microemulsion prepared in step (1) of the dynamic light scattering measurement is 51.61 nm, and the particle size of the microemulsion prepared in step (4) is 50.39 nm.

The prepared catalyst was measured by atomic absorption spectrometry. In Example 11, the Pd content was 0.05%, the Ni content was 0.5%, the Cu content was 0.5%, and the Ag content was 0.08%.

Reduction of the catalyst:

Comparative example 11

The carrier and the preparation steps are the same as in Example 11, except that the particle size of the microemulsion in Comparative Example 11 is smaller than the maximum pore diameter of the carrier.

Catalyst preparation:

(1) Weigh 1.10g of nickel chloride and 1.47g of copper nitrate, dissolve it in 70mL of deionized water, add 37g of n-hexane, add 30g of CATB, add 30g of n-pentanol, and stir well to form a microemulsion. The calcined carrier is immersed in the prepared microemulsion, shaken for 90 minutes, filtered off the remaining liquid, dried at 80°C, and calcined at 500°C for 5 hours, which is called semi-finished catalyst A11-1.

(2) Weigh 0.067g of palladium chloride, dissolve it in 100mL of deionized water, adjust the pH to 1.8, and then immerse the semi-finished catalyst A11-1 in the prepared Pd salt solution. After immersing for 60 minutes, dry at 100°C and 500°C. It is calcined for 5 hours under the conditions to obtain the semi-finished catalyst B11-1.

(3) Weigh 0.126g of silver nitrate, dissolve it in 57mL of deionized water, adjust the pH to 3, dissolve the semi-finished catalyst B11-1 prepared in step (2) in the prepared silver-containing silver nitrate solution, and shake After the solution is completely absorbed, it is dried at 140°C and calcined at 500°C for 5 hours to obtain a semi-finished catalyst C11-1.

(4) Weigh 0.018g of palladium chloride, dissolve it in 70mL of deionized water, add 37g of n-hexane, add 30g of CATB, add 30g of n-pentanol, stir well to form a microemulsion, and impregnate the semi-finished catalyst C11-1 into the prepared In the microemulsion, shake for 90 minutes, filter out the remaining liquid, dry at 80°C, and calcinate at 500°C for 5 hours to obtain the desired catalyst.

The particle size of the microemulsion prepared in step (1) of the dynamic light scattering measurement is 30.87 nm, and the particle size of the microemulsion prepared in step (4) is 30.24 nm.

The prepared catalyst was determined by atomic absorption spectrometry. In Comparative Example 11, the Pd content was 0.05%, the Ni content was 0.5%, the Cu content was 0.5%, and the Ag content was 0.08%.

Reduction of the catalyst:

Example 12

Catalyst preparation:

Weigh a commercially available bimodal pore distribution spherical alumina carrier with a diameter of 4 mm. After calcination at 1088°C for 4 hours, the pore size distribution ranges are 20-46 nm and 85-350 nm, water absorption rate is 55%, and specific surface area is 39.29 m ² /g. Weigh 100 g of the carrier.

(1) Weigh 0.08g of palladium chloride salt and dissolve it in 140mL of deionized water, adjust the pH to 2, then add the prepared carrier to the Pd salt solution, immerse and adsorb for 50min, then dry at 110°C, and roast at 550°C 5h to obtain the desired semi-finished catalyst A12.

(2) Weigh 4.93g nickel nitrate and 1.47g copper nitrate, dissolve in 71.5g water, add 27.5g n-hexane, 13.80g CTAB, 12.73g n-pentanol and fully stir to form a microemulsion, add the semi-finished catalyst A12 to the prepared After immersing in the microemulsion for 80 minutes, filter out the remaining liquid, and use deionized water lotion to neutralize. It was dried at 80°C and calcined at 550°C for 5 hours. A semi-finished catalyst B12 was obtained.

(3) Weigh 0.021 g of palladium nitrate, dissolve it in 71.5 g of water, add 27.5 g of n-hexane, 13.80 g of CTAB, and 12.73 g of n-pentanol to fully stir to form a microemulsion, and add the semi-finished catalyst B12 to the prepared microemulsion for impregnation After 80 minutes, filter out the remaining liquid, and use deionized water lotion to make it neutral. It was dried at 80°C and calcined at 450°C for 6 hours to obtain a semi-finished catalyst C12.

(4) Take 49.5mL of deionized water, add 0.291g of silver nitrate to make it completely dissolved, adjust the pH to 2, immerse the semi-finished catalyst C12 in the prepared solution, shake for 10 minutes, dry at 100°C, and roast at 550°C for 6 hours , That is to obtain the desired catalyst.

The particle size of the microemulsion prepared in step (2) was determined to be 98.78 nm by the dynamic light scattering method, and the particle size of the microemulsion prepared in step (3) was 99.31 nm.

The element content was measured by atomic absorption spectrometry to obtain the catalyst prepared in Example 12. The Pd content was 0.057%, the Ni content was 1.57%, the Cu content was 0.5%, and the Ag content was 0.18%.

Reduction of the catalyst:

Reducing gas: hydrogen, reducing space velocity: 100h ^-1 , temperature 150℃, keep for 4h.

Comparative example 12

The catalyst carrier is the same as in Example 12, and the catalyst preparation conditions are also the same. The difference is that the loading of Cu is less than 1/10 of that of Ni.

Weigh a commercially available bimodal pore distribution spherical alumina carrier with a diameter of 4 mm. After calcination at 1090°C for 4 hours, the pore size distribution ranges are 20-46 nm and 85-350 nm, water absorption rate is 55%, and specific surface area is 39.29 m ² /g. Weigh 100 g of the carrier.

(1) Weigh 0.08g of palladium chloride salt and dissolve it in 140mL of deionized water, adjust the pH to 2, then add the prepared carrier to the Pd salt solution, immerse and adsorb for 50min, then dry at 110°C, and roast at 550°C 5h to obtain the desired semi-finished catalyst A12-1.

(2) Weigh 4.93g nickel nitrate and 0.294g copper nitrate, dissolve it in 71.5g water, add 27.5g n-hexane, 13.80g CTAB, 12.73g n-pentanol and fully stir to form a microemulsion, add the semi-finished catalyst A12-1 to After immersing the prepared microemulsion for 80 minutes, filter out the remaining liquid, and use deionized water lotion to make it neutral. It was dried at 80°C and calcined at 550°C for 5 hours. A semi-finished catalyst B12-1 was obtained.

(3) Weigh 0.021g of palladium nitrate, dissolve it in 71.5g of water, add 27.5g of n-hexane, 13.80g of CTAB, and 12.73g of n-pentanol to fully stir to form a microemulsion, add the semi-finished catalyst B12-1 to the prepared microemulsion After immersing in the medium for 80 minutes, filter out the remaining liquid, and use deionized water lotion to make it neutral. It was dried at 80°C and calcined at 450°C for 6 hours to obtain a semi-finished catalyst C12-1.

(4) Take 49.5mL of deionized water, add 0.291g of silver nitrate to make it completely dissolve, adjust the pH to 2, immerse the semi-finished catalyst C12-1 in the prepared solution, shake for 10min, dry at 100°C, and roast at 550°C After 6 hours, the desired catalyst was prepared.

The element content was determined by atomic absorption spectrometry, and the catalyst prepared in Comparative Example 12 was obtained. The Pd content was 0.057%, the Ni content was 1.57%, the Cu content was 0.1%, and the Ag content was 0.18%.

Reduction of the catalyst:

Example 13

Catalyst preparation:

Weigh a commercially available bimodal pore distribution spherical alumina carrier with a diameter of 4 mm. After being calcined at 1112°C for 4 hours, the pore size distribution ranges are 26-47 nm and 95-450 nm, water absorption rate is 55%, and specific surface area is 25.45 m ² /g. Weigh 100 g of the carrier.

(1) Weigh 0.075 palladium nitrate and dissolve it in 44mL deionized water, adjust the pH to 2, spray the prepared solution on the prepared carrier, after the solution is fully absorbed, dry at 100°C, and roast at 500°C for 4h , A semi-finished catalyst A13 is obtained.

(2) Weigh 12.46g of anhydrous nickel nitrate, and dissolve 2.94g of copper nitrate in 70.00g of water, add 35.00g of cyclohexane, 21.00g of TritonX-100, and 20.80g of n-butanol to fully stir to form a microemulsion. The semi-finished catalyst A13 was added to the prepared microemulsion and immersed for 3 hours, the remaining liquid was filtered off, dried at 60°C, and calcined at 500°C for 4 hours. A semi-finished catalyst B13 was obtained.

(3) Weigh 0.0416 g of palladium nitrate and dissolve in 70.00 g of water, add 35.00 g of cyclohexane, 21.00 g of Triton X-100, and 20.80 g of n-butanol to fully stir to form a microemulsion. After adding the semi-finished catalyst B13 to the prepared microemulsion and immersing for 3 hours, the remaining liquid was filtered off, dried at 60°C, and calcined at 550°C for 4 hours to obtain the semi-finished catalyst C13.

(4) Take 60 mL of deionized water, add 0.21 g of silver nitrate to completely dissolve it, adjust the pH to 4, spray the prepared solution on the semi-finished catalyst C13, after the solution is fully absorbed, dry at 110°C, and roast at 550°C More than 4 hours. Prepare the desired catalyst.

The particle size of the microemulsion prepared in step (2) is 50.68nm, and the particle size of the microemulsion prepared in step (3) is 50.32nm.

The element content was determined by atomic absorption spectrometry to obtain the catalyst prepared in Example 13. The Pd content was 0.054%, the Ni content was 4%, the Cu content was 1%, and the Ag content was 0.13%.

Reduction of the catalyst:

Reducing gas: hydrogen, reducing space velocity: 100h ^-1 , temperature 200℃, keeping for 8h.

Comparative example 13

The same carrier as in Example 13 was used, and the active ingredients were added in the same amount. The difference is that all Pd was loaded by the emulsion method.

Catalyst preparation:

(1) Weigh 12.46g of anhydrous nickel nitrate, dissolve 2.94g of copper nitrate in 70.00g of water, add 35.00g of cyclohexane, 21.00g of TritonX-100, and 20.80g of n-butanol to fully stir to form a microemulsion. The semi-finished catalyst A13 was added to the prepared microemulsion and immersed for 3 hours, the remaining liquid was filtered off, dried at 60°C, and calcined at 500°C for 4 hours. A semi-finished catalyst A13-1 was obtained.

(2) Weigh 0.1166 g of palladium nitrate and dissolve in 70.00 g of water, add 35.00 g of cyclohexane, 21.00 g of Triton X-100, and 20.80 g of n-butanol to fully stir to form a microemulsion. The semi-finished catalyst A13-1 was added to the prepared microemulsion and immersed for 3 hours, the remaining liquid was filtered off, dried at 60°C, and calcined at 550°C for 4 hours to obtain the semi-finished catalyst B13-1.

(3) Take 60 mL of deionized water, add 0.21 g of silver nitrate to completely dissolve it, adjust the pH to 4, spray the prepared solution on the semi-finished catalyst C13-1, and after the solution is fully absorbed, dry it at 110°C, 550 Calcined at ℃ for more than 4 hours. Prepare the desired catalyst.

The particle size of the microemulsion prepared in (1) is 50.68nm, and the particle size of the microemulsion prepared in step (2) is 50.34nm as determined by the dynamic light scattering method.

The element content was determined by atomic absorption spectrometry, and the catalyst prepared in Comparative Example 13 was obtained. The Pd content was 0.054%, the Ni content was 4%, the Cu content was 1%, and the Ag content was 0.13%.

Reduction of the catalyst:

Example 14

Catalyst preparation:

Weigh a commercially available bimodal pore distribution spherical alumina carrier with a diameter of 4 mm. After calcination at 1088°C for 4 hours, the pore size distribution ranges are 20-46 nm and 85-350 nm, water absorption rate is 55%, and specific surface area is 40.23 m ² /g. Weigh 100 g of the carrier.

(1) Weigh 4.93g of anhydrous nickel nitrate and 1.47g of copper nitrate, dissolve it in 70mL of deionized water, add 26.92g of n-hexane, add CATB 16.16g, add 16.00g n-pentanol, and stir well to form a microemulsion. After the prepared carrier was added to the prepared microemulsion and immersed for 80 minutes, the remaining liquid was filtered off, dried at 70°C, and calcined at 500°C for 4 hours. A semi-finished catalyst A14 was obtained.

(2) Weigh 0.07g of palladium nitrate and dissolve it in 140mL of deionized water, adjust the pH to 2, then add the prepared semi-finished catalyst A14 to the Pd salt solution, immerse and adsorb for 50min, then dry at 110°C, and calcinate at 550°C 4h to obtain the desired semi-finished catalyst B14.

(3) Weigh 0.023g of palladium nitrate, dissolve it in 70mL deionized water, add 26.92g of n-hexane, add 16.16g of CATB, add 16.00g of n-pentanol, stir well to form a microemulsion, add the semi-finished catalyst B14 to the prepared After being immersed in the microemulsion for 80 minutes, the remaining liquid was filtered off, dried at 70°C, and calcined at 550°C for 4 hours to obtain a semi-finished catalyst C14.

(4) Take 49.5mL of deionized water, add 0.291g of silver nitrate to completely dissolve it, adjust the pH to 2, immerse the semi-finished catalyst C14 in the prepared solution, shake for 10 minutes, dry at 100°C, and calcinate at 550°C for 4 hours , That is to obtain the desired catalyst.

The particle size of the microemulsion prepared in step (1) was determined to be 80.28 nm by the dynamic light scattering method, and the particle size of the microemulsion prepared in step (3) was 80.56 nm.

The element content was determined by atomic absorption spectrometry to obtain the catalyst prepared in Example 14. The Pd content was 0.043%, the Ni content was 1.57%, the Cu content was 0.5%, and the Ag content was 0.18%.

Reduction of the catalyst:

Comparative example 14

Catalyst preparation:

The same carrier as in Example 14 was used, and the preparation conditions were the same as in Example 14, except that the solution method supported copper and nickel.

(1) Weigh 4.93g of anhydrous nickel nitrate and 1.47g of copper nitrate, dissolve it in 71.5g of water, stir thoroughly, add the prepared carrier to the prepared solution and soak for 80min, filter out the remaining liquid, and put it at 70℃ It is dried at the bottom and calcined at 500°C for 4 hours. A semi-finished catalyst A14-1 was obtained.

(2) Weigh 0.07g of palladium nitrate and dissolve it in 140mL of deionized water, adjust the pH to 2, then add the prepared semi-finished catalyst A14-1 to the Pd salt solution, immerse and absorb for 50 minutes, dry at 110°C, and condition at 550°C It is calcined for 4 hours to obtain the desired semi-finished catalyst B14-1.

(3) Weigh 0.023g of palladium nitrate, dissolve it in 70mL of deionized water, add 26.92g of n-hexane, add 16.16g of CATB, add 16.00g of n-pentanol, stir well to form a microemulsion, add the semi-finished catalyst B14-1 to the system After being immersed in a good microemulsion for 80 minutes, the remaining liquid was filtered off, dried at 70°C, and calcined at 550°C for 4 hours to obtain a semi-finished catalyst C14-1.

(4) Take 49.5mL of deionized water, add 0.291g of silver nitrate to make it completely dissolve, adjust the pH to 2, immerse the semi-finished catalyst C14-1 in the prepared solution, shake for 10min, dry at 100°C, and roast at 550°C In 4 hours, the desired catalyst was prepared.

The particle size of the microemulsion prepared in step (3) was determined to be 80.56 nm by the dynamic light scattering method.

The element content was determined by atomic absorption spectrometry, and the catalyst prepared in Comparative Example 14 was obtained. The Pd content was 0.043%, the Ni content was 1.57%, the Cu content was 0.5%, and the Ag content was 0.18%.

Reduction of the catalyst:

Example 15

Catalyst preparation:

Weigh a commercially available bimodal pore distribution spherical alumina carrier with a diameter of 4 mm. After calcination at 1092°C for 4 hours, the pore size distribution ranges are 20-45 nm and 85-350 nm, water absorption is 55%, and specific surface area is 39.47 m ² /g. Weigh 100 g of the carrier.

(1) Weigh 4.93g of anhydrous nickel nitrate and 1.47g of copper nitrate, dissolve it in 71.5g of water, add 27.5g of isopentane, 13.75g CTAB, 12.60g n-hexanol and fully stir to form a microemulsion, add the prepared carrier After being immersed in the prepared microemulsion for 80 minutes, the remaining liquid was filtered off, dried at 70°C, and calcined at 500°C for 4 hours. A semi-finished catalyst A15 was obtained.

(2) Weigh 0.064g of palladium nitrate and dissolve it in 140mL of deionized water, adjust the pH to 2, then add the prepared semi-finished catalyst A15 to the Pd salt solution, immerse and absorb for 50 minutes, dry at 110°C, and calcinate at 550°C 6h to obtain the desired semi-finished catalyst B15.

(3) Weigh 0.022g palladium nitrate, dissolve it in 71.5g water, add 27.5g isopentane, 13.75g CTAB, 12.60g n-hexanol and fully stir to form a microemulsion, add the semi-finished catalyst B15 to the prepared microemulsion and soak After 80 minutes, the remaining liquid was filtered off, dried at 70°C, and calcined at 550°C for 4 hours to obtain a semi-finished catalyst C15.

(4) Take 49.5mL of deionized water, add 0.291g of silver nitrate to completely dissolve it, adjust the pH to 2, immerse the semi-finished catalyst C15 in the prepared solution, shake for 10 minutes, dry at 100°C, and calcinate at 500°C for 6 hours , That is to obtain the desired catalyst.

The particle size of the microemulsion prepared in steps (1) and (3) was determined to be 101.39 nm by dynamic light scattering method.

The element content was determined by atomic absorption spectrometry to obtain the catalyst prepared in Example 15, wherein the Pd content was 0.04%, the Ni content was 1.57%, the Cu content was 0.5%, and the Ag content was 0.18%.

Reduction of the catalyst:

Comparative example 15

Using a unimodal pore size distribution carrier

Catalyst preparation: Weigh a commercially available single-modal pore distribution spherical alumina carrier with a diameter of 4 mm. After calcining at 1092°C for 4 hours, the pore size distribution range is 20-45 nm, which is a single pore size distribution, the water absorption rate is 55%, and the specific surface area is 39.47 m ² /g. Weigh 100 g of the carrier.

(1) Weigh 4.93g of anhydrous nickel nitrate and 1.47g of copper nitrate, dissolve it in 71.5g of water, add 27.5g of isopentane, 13.75g CTAB, 12.60g n-hexanol and fully stir to form a microemulsion, add the prepared carrier After immersing in the prepared microemulsion for 80 minutes, filter out the remaining liquid, and use deionized water lotion to make it neutral. It was dried at 70°C and calcined at 500°C for 4 hours. A semi-finished catalyst A15-1 was obtained.

(2) Weigh 0.064g of palladium nitrate and dissolve it in 140mL of deionized water, adjust the pH to 2, then add the prepared semi-finished catalyst A15-1 to the Pd salt solution, immerse and adsorb for 50min, then dry at 110°C and 550°C. It is calcined for 6 hours to obtain the desired semi-finished catalyst B15-1.

(3) Weigh 0.022g palladium nitrate, dissolve it in 71.5g water, add 27.5g isopentane, 13.75g CTAB, 12.60g n-hexanol and fully stir to form a microemulsion, add the semi-finished catalyst B15-1 to the prepared microemulsion After immersing in the medium for 80 minutes, filter out the remaining liquid, and use deionized water lotion to make it neutral. It was dried at 70°C and calcined at 550°C for 4 hours to obtain a semi-finished catalyst C15-1.

(4) Take 49.5mL of deionized water, add 0.291g of silver nitrate to make it completely dissolve, adjust the pH to 2, immerse the semi-finished catalyst C15-1 in the prepared solution, shake for 10min, dry at 100℃, and roast at 500℃ After 6 hours, the desired catalyst was prepared.

The particle size of the microemulsion prepared in steps (1) and (3) was determined to be 101.39 nm by the dynamic light scattering method.

The element content was determined by atomic absorption spectrometry, and the catalyst prepared in Comparative Example 15 was obtained. The Pd content was 0.034%, the Ni content was 0.32%, the Cu content was 0.11%, and the Ag content was 0.18%.

Reduction of the catalyst:

The performance of the catalyst used in the post-hydrogenation of C2

Evaluation method: The filling amount of the catalyst in the fixed bed section reactor is 100mL (recording weight), the filler is 50mL, the space velocity of the reaction material: 6000/h, the operating pressure is 2.0MPa, the hydrogen-acetylene ratio is 1.2, and the reactor inlet temperature is 40-50℃. .

Table 2 Calculation method of evaluation results

The initial selectivity is the selectivity measured in 24 hours at the beginning of reactor feeding.

The initial activity is the activity measured in 24 hours (acetylene conversion rate) at the beginning of reactor feeding

The composition of the reaction materials is shown in Table 3.

Table 3 Composition of reaction materials

反应物料Reaction mass	C ₂H ₂ C ₂ H ₂	C ₂H ₄ C ₂ H ₄	C ₂H ₆ C ₂ H ₆	C ₃-C ₄ C ₃ -C ₄
含量(v/v％)Content (v/v%)	1.51.5	8686	1212	3×10 ^-3 3×10 ^-3

The catalyst evaluation results are shown in Table 4.

Table 4 Catalyst evaluation results

From the comparison of the catalyst evaluation results in Table 2 and Table 3, it can be seen that:

Compared with Example 1, Comparative Example 1, no Cu is loaded, and the reduction temperature is 200° C., although the initial acetylene conversion rate and selectivity are basically the same as those of the corresponding examples. However, after 1000 hours, it is significantly lower than the examples, indicating that the Cu loading or the catalyst reduction temperature is important for improving the anti-coking performance. Or maybe at a reduction temperature of 200°C, the active center with saturated hydrogenation function does not play its due role.

Comparing Comparative Example 2 with Example 2, the Cu loading in Comparative Example 2 adopts the solution method. Cu is highly uniformly dispersed in the carrier, which does not effectively reduce the Ni reduction temperature. As the reaction progresses, the amount of coking on the catalyst increases significantly. The difference with the catalyst of Example 2 is also becoming more and more obvious.

Compared with Example 3, Comparative Example 3 adopts the solution method to load Pd, Pd enters the small pores, and its activity is very high, and the initial acetylene conversion rate of Comparative Example 3 reaches 100%. When there is no Pd in the macropores, in Comparative Example 3, at 150°C, Ni-Cu is not reduced, the amount of coking is large after 1000 hours, and the catalyst performance decreases greatly;

Compared with Example 4, Comparative Example 4 is not loaded with Ni. As the saturated hydrogenation effect on green oil is reduced, the coking amount of the catalyst after 1000 hours is large, and the performance decline is large.

In Comparative Example 5, the Ni content was reduced to 0.3%. Under this content and reaction conditions, the hydrogenation activity of the Ni-Cu active center was insufficient, and the selective hydrogenation by-products could not be saturated hydrogenation. After 1000 hours, Compared with Example 5, the performance of the catalyst is much lower.

The preparation conditions of the catalyst of Comparative Example 6 were the same as those of Example 6, except that the content of Pd supported by the microemulsion method was significantly reduced. Due to the decrease in Pd content, it can no longer play the role of significantly reducing the Ni reduction temperature, so that Ni does not have an obvious effect on the saturation hydrogenation of the by-products, and the performance gap is obvious after 1000 hours.

Compared with Example 7, the specific surface area of Comparative Example 7 is too large, and the scale of the Pd active center on the catalyst is too small. Although the initial selectivity is better, the initial activity is obviously insufficient. Also due to the excessive surface area, the Ni-Cu active center activity is insufficient, and the amount of coking after 1000 hours is also significantly higher than that of Example 7.

In Example 8, Ag was first loaded during the preparation of the catalyst, and Ag and Pd formed an alloy. The content of Ag in the alloy structure was relatively high and the selective hydrogenation activity was reduced. Therefore, its initial activity was worse than that of Example 7.

In Comparative Example 8, when the microemulsion is loaded with Pd, the particle size of the microemulsion is larger than the maximum pore diameter of the carrier, so that Pd cannot enter the pores of the carrier, and can only be partly supported on the outer surface of the catalyst, and partly lost with the solution. It is better, but Pd cannot effectively form an alloy with Ni-Cu, so it cannot effectively reduce the reduction temperature of Ni-Cu. The green oil molecules could not be effectively saturated and hydrogenated. Therefore, after 1000 hours, the performance of the catalyst in Comparative Example 8 was significantly worse than that in Example 8.

In Example 9, the particle size of the microemulsion when loaded with Pd is 398nm, and the particle size of the microemulsion when loaded with Ni-Cu is 621nm, which is larger than the maximum pore size of the carrier, and the microemulsion containing Ni-Cu cannot enter the pores of the carrier. In the medium, only part of the microemulsion is adsorbed on the surface of the carrier and part of it is lost. The adsorbed part cannot form an alloy with Ni-Cu. When the reduction temperature is 150°C, part of Ni-Cu cannot be effectively reduced, and the green oil molecules cannot be effectively saturated and hydrogenated. Therefore, after 1000 hours, comparative example 9 The reaction effect of the medium catalyst is worse than that of the examples.

In Comparative Example 10, the specific surface area of the catalyst is small. At the same loading amount, the scale of the Pd active center is too large, resulting in high activity and poor selectivity, and the scale of the active center of Ni-Cu is larger, which not only saturates the by-products The hydrogenation function also has a hydrogenation effect on ethylene, resulting in poor selectivity for ethylene hydrogenation. From the point of view of the amount of coking, Comparative Example 10 has a smaller amount of coking after 1000 hours, but the selectivity is significantly lower than that of the Examples.

In Comparative Example 11, when the microemulsion is loaded with each component, the pore size of the emulsion is smaller than the maximum pore size of the carrier pores, so that all the components are loaded in the pores. These components all have hydrogenation activity and are concentrated in the small pores, so that the activity of the hydrogenation active center in the small pores is too high, the initial selectivity is very poor, and the generation of by-products increases. Due to the unreasonable distribution of Ni-Cu active centers, the by-products produced cannot be saturated by hydrogenation. After 1000 hours, the coking is relatively large, and the activity and ethylene selectivity are worse than those in the examples.

In Comparative Example 12, the loading amount of Cu was too small, although Pd, Ni, and Cu formed alloys in the macropores, because Cu is easier to reduce than Ni, it can play a role in promoting the reduction of Ni. However, the Cu content in this comparative example is too low to promote the reduction of Ni, and the catalyst coking is also serious after 1000 hours.

In Comparative Example 13, all Pd was loaded by the microemulsion method, so that Pd was not loaded within the optimal pore diameter of 20-30nm, and all the alloys formed by Pd, Ni and Cu, the active center of which was located in the larger pore, single active The activity of the center is good, and the intrinsic selectivity is poor. Affected by diffusion, the active center in the macropore is not easy to meet the acetylene molecule, so the initial activity is not good, the selectivity is also poor, the formation of by-products is also intensified, and the coking is more serious after 1000 hours. .

In Comparative Example 14, Ni and Cu are supported by the solution method, which are uniformly distributed in the carrier, and it is difficult to form a catalytic reaction center with better activity. Part of the Pd supported by the solution method forms an active center on the outer layer of the carrier, but Ni The existence of Cu is not conducive to improving the selectivity of Pd active centers, but has a negative impact. Therefore, the initial activity of the catalyst is acceptable, but the initial selectivity is poor. Since there is no active center for saturated hydrogenation of the by-products of hydrogenation, the amount of coking is very large after 1000 hours, and the performance decline is very serious.

In Comparative Example 15, a carrier with a single pore size distribution was used. The particle size of the prepared microemulsion was larger than the maximum pore size of the carrier, resulting in that the emulsion could not enter the carrier, and some active components could only be distributed on the outermost layer of the carrier, and some were not effective. Although it has a certain saturation hydrogenation effect on the outer surface, the catalytic effect is still worse than that of Example 15.

Claims

A catalyst for selective hydrogenation of alkynes, wherein the carrier of the catalyst is alumina or mainly alumina, and has a bimodal pore distribution structure, and the specific surface area of the catalyst is 20-50m 2 /g; wherein the pore diameter is 15-50nm, the pore diameter of the macropores is 80-500nm, the catalyst contains at least Pd, Ni, Cu, based on the mass of the carrier as 100%, the content of Pd is 0.035-0.08%, the content of Ni is 0.5-5%, and the weight ratio of Cu to Ni 0.1～1.0, where the microemulsion supports Ni, Cu and part of Pd, the particle size of the microemulsion is not less than the maximum pore diameter but not higher than the maximum pore diameter of the macropore, and the amount of Pd supported by the microemulsion is 1/100～1/200 of Ni+Cu content; part of Pd is supported by solution.
The catalyst according to claim 1, wherein the catalyst further contains Ag, which is supported by a solution, and the content thereof is 0.08 to 0.21%.
The catalyst according to claim 1, wherein the catalyst carrier is alumina or mainly alumina, and has a bimodal pore distribution structure, and the specific surface area of the catalyst is 20-50m 2 /g; wherein the pore diameter is 15- 50nm, the pore diameter of the macropore is 80-500nm, the catalyst contains at least Pd, Ag, Ni, Cu, based on the mass of the carrier as 100%, the content of Pd is 0.035-0.07%, the content of Ag is 0.08-0.21%, and the content of Ni is 0.5-5 %, the weight ratio of Cu to Ni is 0.1～1.0, where Ni, Cu and part of Pd are loaded in the form of microemulsion, mainly distributed in the macropores of the carrier, and the amount of Pd loaded by the microemulsion method is the content of Ni+Cu 1/100～1/200; Ag and part of Pd are supported by solution method.
The catalyst according to claim 1 or 3, wherein the carrier is alumina or mainly alumina; the Al 2 O 3 crystal form is θ, α crystal form or a mixed crystal form; the alumina in the catalyst carrier is more than 80% .
The catalyst according to claim 1 or 3, wherein the microemulsion loading process includes: dissolving the precursor salt in water, adding an oil phase, a surfactant and a co-surfactant, and fully stirring to form a microemulsion, wherein the oil phase is Alkanes or cycloalkanes, the surfactant is an ionic surfactant and/or a nonionic surfactant, and the co-surfactant is an organic alcohol.
The catalyst according to claim 1, 3 or 5, wherein, during the microemulsion loading process, the oil phase is C6-C8 saturated alkanes or cycloalkanes; the surfactant is an ionic surfactant and/or a nonionic surfactant ; Co-surfactant is C4-C6 alcohols.
The catalyst according to claim 6, wherein the oil phase is cyclohexane or n-hexane.
The catalyst according to claim 6, wherein the surfactant is a nonionic surfactant.
The catalyst according to claim 8, wherein the surfactant is polyethylene glycol octyl phenyl ether or cetyl trimethyl ammonium bromide.
The catalyst according to claim 6, wherein the co-surfactant is n-butanol and/or n-pentanol.
The catalyst according to claim 1 or 3, wherein, in the preparation process of the catalyst, the step of loading Pd in the microemulsion is after the step of loading Ni and Cu in the microemulsion.
The catalyst according to claim 1 or 3, wherein, during the preparation process of the catalyst, the order of the solution loading of Pd and the loading of the Ni/Cu microemulsion is not limited.
The catalyst according to claim 1 or 3, wherein, in the preparation process of the catalyst, the step of supporting Ag in the solution is after the step of supporting Pd in the solution.
The preparation method of the catalyst according to any one of claims 1-13, which comprises the following steps:

(1) Dissolve the precursor salts of Ni and Cu in water, add the oil phase, surfactant and co-surfactant, fully stir to form a microemulsion, add the carrier to the prepared microemulsion and soak for 0.5 to 4 hours , The remaining liquid is filtered off, and after drying, it is calcined at 400-600°C for more than 4 hours to obtain semi-finished catalyst A;

(2) Dissolve the precursor salt of Pd in water, adjust the pH to 1.5-2.5, then add the semi-finished catalyst A to the Pd salt solution, immerse and adsorb for 0.5-4h, then dry and calcinate at 400-600℃ for 4～ 6h to obtain semi-finished catalyst B;

(3) Dissolve the Pd precursor salt in water, add the oil phase, surfactant and co-surfactant, fully stir to form a microemulsion, add the semi-finished catalyst B to the prepared microemulsion and soak for 0.5 to 4 hours, The remaining liquid is filtered off, and after drying, it is calcined at 400-600°C for more than 4 hours to obtain the catalyst.
The method for preparing a catalyst according to claim 3, wherein the preparation process specifically comprises the following steps:

(1) Dissolve the precursor salts of Ni and Cu in water, add the oil phase, surfactant and co-surfactant, and stir thoroughly to form a microemulsion; add the carrier to the prepared microemulsion and soak for 0.5 to 4 hours , The remaining liquid is filtered off; after drying, it is calcined at 400-600℃ for 4-6h to obtain semi-finished catalyst A;

(2) Dissolve the Pd precursor salt in water, add the oil phase, surfactant and co-surfactant, fully stir to form a microemulsion, add the semi-finished catalyst A to the prepared microemulsion and soak for 0.5 to 4 hours. The remaining liquid is filtered off; after drying, it is calcined at 400-600°C for 4-6 hours to obtain semi-finished catalyst B;

(3) Dissolve the precursor salt of Pd in water, adjust the pH to 1.5-2.5, then add the semi-finished catalyst B to the Pd salt solution, immerse and adsorb for 0.5-4h, then dry and calcinate at 400-600℃. ~6h to obtain semi-finished catalyst C;

(4) Dissolve the Ag salt in deionization, adjust the pH to 1～5, immerse the semi-finished catalyst C in the prepared solution, dry after the solution is completely absorbed, and calcinate at 400～600℃ for 4～6h to obtain The catalyst.
The method for preparing a catalyst according to claim 3, wherein the preparation process specifically comprises the following steps:

(1) Dissolve the precursor salts of Ni and Cu in water, add the oil phase, surfactant and co-surfactant, and stir thoroughly to form a microemulsion; add the carrier to the prepared microemulsion and soak for 0.5 to 4 hours , The remaining liquid is filtered off; after drying, it is calcined at 400-600℃ for 4-6h to obtain semi-finished catalyst A;

(2) Dissolve the precursor salt of Pd in water, adjust the pH to 1.5-2.5, then add the semi-finished catalyst A to the Pd salt solution, immerse and adsorb for 0.5-4h, then dry and calcinate at 400-600℃. ~6h to obtain semi-finished catalyst B;

(3) The loading of Ag is carried out by saturated dipping, that is, the prepared Ag salt solution is 80-110% of the saturated water absorption of the carrier, adjust the pH to 1-5, dry after dipping, and roast at 400-600℃ , To obtain semi-finished catalyst C;

(4) Dissolve the Pd precursor salt in water, add the oil phase, surfactant and co-surfactant, fully stir to form a microemulsion, add the semi-finished catalyst C to the prepared microemulsion and soak for 0.5 to 4 hours, The remaining liquid is filtered off; after drying, it is calcined at 400-600°C for 4-6 hours to obtain the catalyst.
The preparation method according to any one of claims 14 to 16, wherein the conditions of the microemulsion in the preparation process are: the weight ratio of water phase/oil phase is 2 to 3, and the weight ratio of surfactant/oil phase is 0.15 ~0.6, the weight ratio of surfactant/co-surfactant is 1-1.2, and the particle size of the formed microemulsion is larger than 50nm and smaller than 500nm.