CN104557631B - A kind of method preparing dimethyl sulfoxide - Google Patents

Abstract

The invention provides a method for preparing dimethyl sulfoxide, comprising contacting dimethyl sulfide and at least one oxidizing agent with a titanium-silicon molecular sieve under oxidation reaction conditions, wherein the titanium-silicon molecular sieve contains a first titanium A silicon molecular sieve and a second titanium-silicon molecular sieve, the first titanium-silicon molecular sieve contains a template agent, and the second titanium-silicon molecular sieve does not contain a template agent. The method of the invention can obtain high conversion rate of dimethyl sulfide, effective utilization rate of oxidant and selectivity of dimethyl sulfoxide, and can also obtain long service life of the catalyst.

Description

A kind of method for preparing dimethyl sulfoxide

technical field

The invention relates to a method for preparing dimethyl sulfoxide.

Background technique

Dimethyl sulfoxide (DMSO) is a sulfur-containing organic compound. It is a colorless and transparent liquid at room temperature. It has the characteristics of high polarity, high hygroscopicity, flammability and high boiling point aprotic. Dimethyl sulfoxide is soluble in water, ethanol, acetone, ether and chloroform, is a highly polar inert solvent, widely used as a solvent and reaction reagent, for example, as a processing solvent and spinning solvent in acrylonitrile polymerization, as Polyurethane synthesis solvent and spinning solvent, as a synthesis solvent of polyamide, fluorochloroaniline, polyimide and polysulfone. Moreover, dimethyl sulfoxide has high selective extraction ability and can be used as an extraction solvent for the separation of alkanes and aromatic hydrocarbons. For example, dimethyl sulfoxide can be used for the extraction of aromatic hydrocarbons or butadiene. At the same time, in the pharmaceutical industry, dimethyl sulfoxide can not only be directly used as the raw material and carrier of some drugs, but also can play the role of anti-inflammatory, analgesic, diuretic and sedative, so it is often added to the drug as an active component of analgesic drugs middle. In addition, dimethyl sulfoxide can also be used as a capacitor medium, antifreeze, brake oil and rare metal extractant.

At present, dimethyl sulfoxide is generally produced by dimethyl sulfide oxidation, and the following production processes are generally used.

1. Methanol carbon disulfide method: using methanol and carbon disulfide as raw materials, using γ-Al ₂ O ₃ as a catalyst, first synthesize dimethyl sulfide, and then oxidize with nitrogen dioxide (or nitric acid) to obtain dimethyl sulfoxide.

2. Nitrogen dioxide method: use methanol and hydrogen sulfide as raw materials to generate dimethyl sulfide under the action of γ-alumina; react sulfuric acid with sodium nitrite to obtain nitrogen dioxide; the generated dimethyl sulfide and Nitrogen dioxide is oxidized at 60-80°C to generate crude dimethyl sulfoxide, or directly oxidized with oxygen to generate crude dimethyl sulfoxide; crude dimethyl sulfoxide is distilled under reduced pressure to obtain refined dimethyl sulfoxide base sulfoxide.

3. Dimethyl sulfate method: react dimethyl sulfate with sodium sulfide to produce dimethyl sulfide; react sulfuric acid with sodium nitrite to generate nitrogen dioxide; dimethyl sulfide and nitrogen dioxide undergo oxidation reaction, The crude dimethyl sulfoxide is obtained, which is neutralized and distilled to obtain refined dimethyl sulfoxide.

Dimethyl sulfoxide can also be produced from dimethyl sulfide by anodic oxidation, but the cost of anodic oxidation is high and it is not suitable for large-scale production.

Contents of the invention

The object of the present invention is to provide a method for preparing dimethyl sulfoxide, which uses dimethyl sulfide as a raw material, and obtains dimethyl sulfoxide by oxidizing dimethyl sulfide with an oxidizing agent. The method can obtain High conversion rate of dimethyl sulfide, effective utilization rate of oxidant and selectivity of dimethyl sulfoxide.

The inventors of the present invention have found in the course of their research that when titanium-silicon molecular sieves are used as catalysts to oxidize dimethyl sulfide with an oxidizing agent to prepare dimethyl sulfoxide, if part of the titanium-silicon molecular sieves are titanium-silicon molecular sieves containing a template , and the rest of the titanium-silicon molecular sieve does not contain a template. Compared with using a titanium-silicon molecular sieve without a template as a catalyst alone, it can obtain a further increase in the conversion rate of dimethyl sulfide, the effective utilization of the oxidant and the dimethyl sulfide. sulfone selectivity; and, enable longer catalyst lifetimes. The present invention has been accomplished on this basis.

The invention provides a method for preparing dimethyl sulfoxide, which comprises contacting dimethyl sulfide and at least one oxidizing agent with a titanium-silicon molecular sieve under oxidation reaction conditions, wherein the titanium-silicon molecular sieve comprises the first A titanium-silicon molecular sieve and a second titanium-silicon molecular sieve, the first titanium-silicon molecular sieve contains a template agent, and the second titanium-silicon molecular sieve does not contain a template agent.

According to the method of the present invention, compared with the preparation of dimethyl sulfoxide by directly oxidizing dimethyl sulfide with an oxidizing agent without using titanium-silicon molecular sieve as a catalyst, a significantly improved conversion rate of dimethyl sulfide can be obtained, and the oxidizing agent is effective. Utilization and DMSO selectivity. Compared with titanium-silicon molecular sieves that use titanium-silicon molecular sieves as catalysts, all titanium-silicon molecular sieves are titanium-silicon molecular sieves that do not contain templates, which can further improve the conversion rate of dimethyl sulfide, the effective utilization rate of oxidants and the dimethyl sulfoxide Selectivity, while also enabling longer catalyst life. Compared with titanium-silicon molecular sieves that use titanium-silicon molecular sieves as catalysts, all titanium-silicon molecular sieves are titanium-silicon molecular sieves containing templates, which can significantly improve the conversion rate of dimethyl sulfide, the effective utilization of oxidants and the yield of dimethyl sulfoxide. selective.

detailed description

The invention provides a method for preparing dimethyl sulfoxide, which comprises contacting dimethyl sulfide and at least one oxidizing agent with titanium silicon molecular sieve under oxidation reaction conditions.

According to the method of the present invention, the titanium-silicon molecular sieve is a general term for a type of zeolite in which titanium atoms replace a part of silicon atoms in the lattice framework, and can be represented by the chemical formula xTiO ₂ ·SiO ₂ . The present invention has no special limitation on the content of titanium atoms in the titanium-silicon molecular sieve, which can be a conventional choice in the field. Specifically, x may be 0.0001-0.05, preferably 0.01-0.03, more preferably 0.015-0.025.

The titanium-silicon molecular sieve can be a common titanium-silicon molecular sieve with various topological structures, for example: the titanium-silicon molecular sieve can be selected from a titanium-silicon molecular sieve with an MFI structure (such as TS-1), a titanium-silicon molecular sieve with a MEL structure ( Such as TS-2), titanium-silicon molecular sieves with BEA structure (such as Ti-Beta), titanium-silicon molecular sieves with MWW structure (such as Ti-MCM-22), titanium-silicon molecular sieves with hexagonal structure (such as Ti-MCM-41, Ti- SBA-15), titanium-silicon molecular sieves with MOR structure (such as Ti-MOR), titanium-silicon molecular sieves with TUN structure (such as Ti-TUN) and titanium-silicon molecular sieves with other structures (such as Ti-ZSM-48) or Various.

Preferably, the titanium-silicon molecular sieve is one or more selected from the group consisting of titanium-silicon molecular sieves with MFI structure, titanium-silicon molecular sieves with MEL structure and titanium-silicon molecular sieves with BEA structure. More preferably, the titanium-silicon molecular sieve is a titanium-silicon molecular sieve with an MFI structure, such as TS-1 molecular sieve.

From the perspective of further improving the conversion rate of dimethyl sulfide, the effective utilization rate of the oxidant, and the selectivity of dimethyl sulfone, the titanium-silicon molecular sieve is a titanium-silicon molecular sieve with an MFI structure, and the crystal grains of the titanium-silicon molecular sieve It is a hollow structure, the radial length of the hollow part of the hollow structure is 5-300 nanometers, and the titanium-silicon molecular sieve is measured under the conditions of 25 ° C, P/P ₀ =0.10, and an adsorption time of 1 hour. The adsorption capacity is at least 70 mg/g, and there is a hysteresis loop between the adsorption isotherm and the desorption isotherm of the low-temperature nitrogen adsorption of the titanium-silicon molecular sieve. Herein, the titanium-silicon molecular sieve with this structure is called hollow titanium-silicon molecular sieve. The hollow titanium-silicon molecular sieve can be obtained commercially (for example, the molecular sieve with the trademark HTS purchased from Sinopec Hunan Jianchang Petrochemical Co., Ltd.), or can be prepared according to the method disclosed in CN1132699C.

According to the method of the present invention, the titanium-silicon molecular sieve is used as a catalyst for oxidizing dimethyl sulfide, and its dosage may be the catalyst amount capable of realizing the catalytic function. Specifically, the weight ratio of dimethyl sulfide to the titanium-silicon molecular sieve may be 0.1-50:1, preferably 1-50:1.

According to the method of the present invention, the titanium-silicon molecular sieve can be a titanium-silicon molecular sieve raw powder, or a formed titanium-silicon molecular sieve.

According to the method of the present invention, the titanium-silicon molecular sieve includes a first titanium-silicon molecular sieve and a second titanium-silicon molecular sieve.

The first titanium-silicon molecular sieve contains a template agent, that is, the first titanium-silicon molecular sieve is a titanium-silicon molecular sieve containing a template agent. The titanium-silicon molecular sieve containing the template refers to the titanium-silicon molecular sieve containing the residual template in the synthesis process, that is: the titanium-silicon molecular sieve has not undergone the process of removing the template after synthesis (such as roasting), or even if the titanium-silicon Molecular sieves have undergone the process of removing templates, but not all templates have been removed.

In the first titanium-silicon molecular sieve, the content of the template agent is not particularly limited, and can be selected according to the type of the titanium-silicon molecular sieve and specific hydrolysis reaction conditions. Generally, in the first titanium-silicon molecular sieve, the content of the template agent can be 0.1-25% by weight. Preferably, in the first titanium-silicon molecular sieve, the content of the template agent is 1-20% by weight. More preferably, in the first titanium-silicon molecular sieve, the content of the template agent is 5-15% by weight. The content of the template agent can be determined by thermogravimetric analysis. Generally, the percentage of weight loss between 200-800° C. in the thermogravimetric analysis can be used as the content of the template agent.

The template agent can be various template agents commonly used in the process of synthesizing titanium-silicon molecular sieves, for example: the template agent can be one or more of quaternary ammonium bases, aliphatic amines and aliphatic alcohol amines. _The quaternary ammonium base can be various organic quaternary ammonium bases, and the aliphatic amine can be a compound formed after at least one hydrogen in various NH is replaced by an aliphatic hydrocarbon group (such as an alkyl group). Alcohol amines can be compounds formed after at least one hydrogen in various _NH3 is replaced by a hydroxyl-containing aliphatic group (such as an alkyl group).

Specifically, the basic template agent may be one or more selected from the group consisting of quaternary ammonium bases represented by general formula I, aliphatic amines represented by general formula II and aliphatic alcohol amines represented by general formula III.

In formula I, each of R ₁ , R ₂ , R ₃ and R ₄ is a C ₁ -C ₄ alkyl group, including a C ₁ -C ₄ straight chain alkyl group and a C ₃ -C ₄ branched chain alkyl group, for example : each of R ₁ , R ₂ , R ₃ and R ₄ can be methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl or tert-butyl.

R ⁵ (NH ₂ ) _n (Formula II)

In formula II, n is an integer of 1 or 2. When n is 1, R ⁵ is C ₁ -C ₆ alkyl, including C ₁ -C ₆ straight chain alkyl and C ₃ -C ₆ branched chain alkyl, such as methyl, ethyl, n-propyl , isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, neopentyl, isopentyl, tert-pentyl and n-hexyl. When n is 2, R ⁵ is C ₁ -C ₆ alkylene, including C ₁ -C ₆ straight chain alkylene and C ₃ -C ₆ branched chain alkylene, such as methylene, ethylene , n-propylene, n-butylene, n-pentylene or n-hexylene.

(HOR ⁶ ) _m NH _(3-m) (Formula III)

In formula III, m R ⁶ are the same or different, and each is a C ₁ -C ₄ alkylene group, including a C ₁ -C ₄ straight chain alkylene group and a C ₃ -C ₄ branched chain alkylene group, such as methylene, ethylene, n-propylene and n-butylene; m is 1, 2 or 3.

The templating agent can specifically be but not limited to: tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide (including various isomers of tetrapropylammonium hydroxide, such as tetra-n-propyl butylammonium hydroxide and tetraisopropylammonium hydroxide), tetrabutylammonium hydroxide (including the various isomers of tetrabutylammonium hydroxide, such as tetra-n-butylammonium hydroxide and tetraisobutylammonium hydroxide), ethylamine, n-propylamine , n-butylamine, di-n-propylamine, butylenediamine, hexamethylenediamine, monoethanolamine, diethanolamine, and triethanolamine. Preferably, the templating agent is tetraethylammonium hydroxide, tetrapropylammonium hydroxide and tetrabutylammonium hydroxide.

The second titanium-silicon molecular sieve does not contain a template agent, that is, the second titanium-silicon molecular sieve is a titanium-silicon molecular sieve that does not contain a template agent. In the present invention, "does not contain a template agent" means that the content of the template agent in the molecular sieve is less than 0.1% by weight. If the synthesized titanium-silicon molecular sieve has undergone a process such as calcination, it usually no longer contains a template. The second titanium-silicon molecular sieve may be various common titanium-silicon molecular sieves from which template agents have been removed.

In various industrial devices that use titanium-silicon molecular sieves as catalysts, such as ammoximation reaction, hydroxylation reaction and epoxidation reaction devices, usually after the device has been running for a period of time, the catalytic activity of the catalyst decreases, and it needs to be carried out in the device or External regeneration, when it is difficult to obtain satisfactory activity even with regeneration, it is necessary to discharge the catalyst from the unit (i.e., replace the catalyst), and the discharged catalyst (i.e., discharge agent or spent catalyst) is currently disposed of The method is usually stacking and burying. On the one hand, it takes up valuable land resources and storage space. On the other hand, the production cost of titanium-silicon molecular sieve is relatively high, and direct disposal also causes great waste. The inventors of the present invention found in the research process that if these unloading agents are regenerated as at least part of the second titanium silicate molecular sieve, high dimethyl sulfide conversion and dimethyl sulfoxide selectivity can still be obtained, and A higher effective utilization rate of the oxidizing agent can be obtained, and the conversion rate of dimethyl sulfide and the selectivity of dimethyl sulfoxide are more stable in the continuous reaction process.

Therefore, in a preferred embodiment of the present invention, at least part of the second titanium-silicon molecular sieve is the unloading agent of the regenerated reaction device using the titanium-silicon molecular sieve as a catalyst. According to this preferred embodiment, when high dimethyl sulfide conversion rate, oxidant effective utilization rate and dimethyl sulfoxide selectivity can be obtained, the reuse of waste titanium silicon molecular sieve can also be realized, further reducing the cost of the present invention. cost of the method.

The unloading agent may be the unloading agent unloaded from various devices using titanium silicate molecular sieve as the catalyst, for example, it may be the unloaded agent unloaded from the oxidation reaction device. Described oxidation reaction can be various oxidation reactions, and for example described unloading agent can be one of the unloading agent of ammoximation reaction unit, the unloading agent of hydroxylation reaction unit and the unloading agent of epoxidation reaction unit. Specifically, it can be one or more of the discharge agent of the cyclohexanone ammoximation reaction device, the discharge agent of the phenol hydroxylation reaction device and the discharge agent of the propylene epoxidation reaction device.

The conditions for regenerating the unloading agent are not particularly limited, and can be appropriately selected according to the source of the unloading agent, for example: high-temperature roasting and/or solvent washing.

The activity of the regenerated unloading agent varies according to its source. Generally, the activity of the regenerated unloading agent may be 5-95% of the activity of the titanosilicate molecular sieve when fresh (ie, the activity of the fresh agent). Preferably, the activity of the regenerated unloading agent may be 10-90% of the fresh activity of the titanium-silicon molecular sieve, more preferably 10-50% of the fresh activity. When the activity of the regenerated unloading agent is 10-50% of the activity of the titanium silicate molecular sieve when it is fresh, not only satisfactory dimethyl sulfide conversion and dimethyl sulfoxide selectivity can be obtained, but also A further improved effective utilization rate of the oxidizing agent can be obtained. The activity of the fresh titanium-silicon molecular sieve is generally above 90%, usually above 95%.

Described activity is measured by the following method: respectively use the regenerated unloading agent and the fresh agent as the catalyzer of cyclohexanone ammoximation reaction, the condition of this ammoximation reaction is: titanium silicon molecular sieve, ammoniacal liquor of 36% by weight ( Calculated as NH ₃ ), 30% by weight of hydrogen peroxide (calculated as H ₂ O ₂ ), tert-butanol and cyclohexanone in a weight ratio of 1:7.5:10:7.5:10, reacted at 80°C for 2 hours under atmospheric pressure. Calculate respectively the conversion rate of cyclohexanone when the unloading agent and the fresh agent sieve are catalyzed through regeneration, and use it as the activity of the unloading agent and the fresh agent through regeneration, wherein, the conversion rate=[( The molar amount of cyclohexanone added - the molar amount of unreacted cyclohexanone)/the molar amount of cyclohexanone added]×100%.

When at least part of the second titanium-silicon molecular sieve is the regenerated reaction device discharging agent, based on the total amount of the second titanium-silicon molecular sieve, the content of the regenerated reaction device discharging agent is preferably more than 5% by weight, In this way, not only can a better effect of improving the effective utilization rate of the oxidant be obtained, but also the reaction process is more stable and easy to control, and at the same time, a higher conversion rate of dimethyl sulfide and a selectivity of dimethyl sulfoxide can be obtained. According to the method of the present invention, even if all the second titanium-silicon molecular sieves are discharged from the regenerated reaction device, satisfactory dimethyl sulfide conversion rate, effective utilization rate of oxidant and dimethyl sulfoxide selectivity can still be obtained. sex. On the premise of obtaining a high effective utilization rate of the oxidant, from the perspective of further improving the conversion rate of dimethyl sulfide and the selectivity of dimethyl sulfoxide, based on the total amount of the second titanium-silicon molecular sieve, The content of the regenerated reactor discharge agent is more preferably 50-80% by weight.

According to the method of the present invention, the ratio between the first titanium-silicon molecular sieve and the second titanium-silicon molecular sieve can be selected according to specific reaction conditions and is not particularly limited. Generally, based on the total amount of the titanium-silicon molecular sieve, the content of the first titanium-silicon molecular sieve can be 5-95% by weight, preferably 10-90% by weight, more preferably 15-50% by weight; The content of the second titanium-silicon molecular sieve may be 5-95% by weight, preferably 10-90% by weight, more preferably 80-85% by weight.

The oxidizing agent can be various substances commonly used in the art that can oxidize dimethyl sulfide to form dimethyl sulfoxide. The method of the present invention is particularly suitable for the occasion of preparing dimethyl sulfoxide by oxidizing dimethyl sulfide with peroxide as an oxidant, which can significantly improve the effective utilization rate of peroxide and reduce the yield of dimethyl sulfoxide. Cost of production. The peroxide refers to a compound containing an -O-O- bond in the molecular structure, which can be hydrogen peroxide and/or an organic peroxide, and its specific examples can include but are not limited to: hydrogen peroxide, tert-butyl hydroperoxide , cumene peroxide, cyclohexyl hydroperoxide, peracetic acid and peroxypropionic acid. Preferably, the oxidizing agent is hydrogen peroxide, which can further reduce the separation cost. The hydrogen peroxide may be hydrogen peroxide commonly used in the art in various forms.

From the point of view of further improving the safety of the method according to the invention, the method according to the invention preferably uses hydrogen peroxide in the form of an aqueous solution. According to the method of the present invention, when the hydrogen peroxide is provided in the form of an aqueous solution, the concentration of the aqueous hydrogen peroxide solution can be a conventional concentration in the field, for example: 20-80% by weight. The aqueous solution of hydrogen peroxide whose concentration meets the above requirements can be prepared by conventional methods, and can also be obtained commercially, for example: it can be commercially available 30% by weight hydrogen peroxide, 50% by weight hydrogen peroxide or 70% by weight hydrogen peroxide.

The amount of the oxidizing agent can be conventionally selected and is not particularly limited. Generally, the molar ratio of dimethyl sulfide to oxidant can be 1:0.1-2, preferably 1:0.5-1.5.

According to the method of the present invention, from the perspective of further improving the degree of mixing between the reactants in the reaction system, enhancing diffusion and more conveniently adjusting the intensity of the reaction, the contacting is preferably in the presence of at least one solvent conduct. The kind of the solvent is not particularly limited. Generally, the solvent can be selected from water, C ₁ -C ₆ alcohols, C ₃ -C ₈ ketones and C ₂ -C ₆ nitriles. Specific examples of the solvent may include, but are not limited to, water, methanol, ethanol, n-propanol, isopropanol, t-butanol, isobutanol, acetone, methyl ethyl ketone, and acetonitrile. Preferably, the solvent is selected from water and C ₁ -C ₆ alcohols. More preferably, the solvent is methanol and/or water. The water used as the solvent can be water from various sources. When the oxidizing agent is hydrogen peroxide and the hydrogen peroxide is provided in the form of an aqueous solution, the water in the aqueous hydrogen peroxide solution can be used as a solvent.

The amount of the solvent used is not particularly limited, and can be conventionally selected. Generally, the weight ratio of solvent to dimethyl sulfide can be 0.1-1000:1, preferably 1-800:1, more preferably 5-200:1. In addition, the amount of the solvent can also be properly adjusted according to the different forms of contacting the dimethyl sulfide and the oxidizing agent with the titanium-silicon molecular sieve.

According to the method of the present invention, the oxidation reaction conditions are not particularly limited, and may be conventionally selected in the art. Generally, the oxidation reaction conditions include: the temperature may be 0-100° C., preferably 20-80° C.; the pressure may be 0-3 MPa, preferably 0.1-2.5 MPa in terms of gauge pressure.

According to the method of the present invention, either batch operation or continuous operation can be used.

The method according to the present invention may also include separating the contacted mixture containing dimethyl sulfoxide, so as to separate the dimethyl sulfoxide therein. In the present invention, there is no special limitation on the method for separating dimethyl sulfoxide in the mixture obtained by contacting, and it can be a conventional choice in the art. For example, dimethyl sulfoxide can be obtained by fractional distillation of the mixture obtained by contacting.

The present invention will be further described below in conjunction with the examples, but the content of the present invention is not limited thereby.

In the following examples and comparative examples, unless otherwise specified, the reagents used are all commercially available reagents.

In the following examples and comparative examples, the hydrogen peroxide used is 30% by weight of hydrogen peroxide.

In the following examples and comparative examples, the pressures are all in gauge pressure.

In the following examples and comparative examples, the content of the template agent in the titanium-silicon molecular sieve containing the template agent was determined by thermogravimetric method. The weight loss rate of the silicon molecular sieve between 200-800°C, the weight loss rate corresponds to the content of the template agent, wherein the heating rate is 10°C/min, and the test is carried out in an air atmosphere.

In the following examples and comparative examples, gas chromatography is used to analyze the content of each component in the reaction solution obtained, and on this basis, the following formulas are used to calculate the conversion rate of dimethyl sulfide, the effective utilization rate of the oxidant and the two Selectivity of methyl sulfoxide:

Conversion rate of dimethyl sulfide = [(molar amount of dimethyl sulfide added - molar amount of unreacted dimethyl sulfide)/molar amount of dimethyl sulfide added] × 100%;

Effective utilization rate of oxidant = [the molar amount of dimethyl sulfoxide produced by the reaction / (the molar amount of added oxidant - the molar amount of unreacted oxidant)] × 100%;

Dimethyl sulfoxide selectivity=[the molar amount of dimethyl sulfoxide produced in the reaction/(the molar amount of added dimethyl sulfide-the molar amount of unreacted dimethyl sulfide)]×100%.

Examples 1-10 illustrate the method of the present invention.

Example 1

(1) Provide catalyst

The second titanium-silicon molecular sieve used in this example is titanium-silicon molecular sieve TS-1, prepared according to the method described in Zeolites, 1992, Vol.12, pages 943-950, and the specific method is as follows.

At room temperature (20°C), mix 22.5 grams of tetraethyl orthosilicate with 7.0 grams of tetrapropylammonium hydroxide as a template, add 59.8 grams of distilled water, stir and mix, then hydrolyze at normal pressure and 60°C for 1.0 hour , to obtain a hydrolysis solution of tetraethyl orthosilicate. Under vigorous stirring, a solution consisting of 1.1 g of tetrabutyl titanate and 5.0 g of anhydrous isopropanol was slowly added to the hydrolysis solution, and the resulting mixture was stirred at 75° C. for 3 hours to obtain a clear transparent colloid. The colloid was placed in a sealed stainless steel reaction kettle, and kept at a constant temperature of 170° C. for 36 hours to obtain a mixture of crystallized products. The resulting mixture was filtered, and the collected solid matter was washed with water, dried at 110°C for 60 minutes, and then calcined at 500°C for 6 hours to obtain a second titanium-silicon molecular sieve with a titanium oxide content of 2.5% by weight.

The first titanium-silicon molecular sieve was prepared by the same method as the second titanium-silicon molecular sieve, the difference was that instead of roasting at 500°C, the titanium-silicon molecular sieve TS-1 containing the template obtained after drying at 110°C for 60 minutes was used as The first titanium silicate molecular sieve has a titanium oxide content of 2.5% by weight and a templating agent content of 14.2% by weight.

Mix the second titanium-silicon molecular sieve with the first titanium-silicon molecular sieve at a weight ratio of 2:1 to obtain catalyst C1.

(2) Preparation of dimethyl sulfoxide

Send dimethyl sulfide, hydrogen peroxide as an oxidant, methanol as a solvent, and catalyst C1 into a slurry bed reactor equipped with a membrane separator for oxidation reaction to obtain a mixture containing dimethyl sulfoxide. Among them, the molar ratio of dimethyl sulfide to oxidant is 1:1, the weight ratio of dimethyl sulfide to catalyst C1 is 5:1, the weight ratio of solvent to catalyst C1 is 50:1, and the reaction temperature is 30°C , the pressure in the reactor is 0.5MPa, and the volume space velocity of the reaction material is 20h-1.

The reaction mixture is separated in a membrane separator into a liquid phase mixture containing dimethyl sulfoxide and a catalyst residue, and the catalyst residue is sent to the reactor for recycling.

The liquid phase mixture containing dimethyl sulfoxide was analyzed by gas chromatography, and the conversion rate of dimethyl sulfide, the effective utilization rate of oxidant and the selectivity of dimethyl sulfoxide were calculated. Wherein, the results obtained by analyzing the mixtures output from the reactor when the reaction was carried out to 0.5 hour and 6 hours respectively are listed in Table 1.

Comparative example 1

(1) A catalyst is provided by the same method as in Example 1, except that instead of using the second titanium-silicon molecular sieve, the first titanium-silicon molecular sieve is used as the catalyst D1.

(2) Dimethyl sulfoxide was prepared by the same method as in Example 1, except that the catalyst C1 was replaced by the same amount of catalyst D1.

Wherein, the results obtained by analyzing the mixtures output from the reactor when the reaction was carried out to 0.5 hour and 6 hours respectively are listed in Table 1.

Comparative example 2

(1) A catalyst is provided by the same method as in Example 1, except that instead of using the first titanium-silicon molecular sieve, the second titanium-silicon molecular sieve is used as the catalyst D2.

(2) Dimethyl sulfoxide was prepared by the same method as in Example 1, except that the catalyst C1 was replaced by the same amount of catalyst D2.

Wherein, the results obtained by analyzing the mixtures output from the reactor when the reaction was carried out to 0.5 hour and 6 hours respectively are listed in Table 1.

Example 2

(1) A catalyst was provided by the same method as in Example 1, except that the second titanium-silicon molecular sieve was mixed with the first titanium-silicon molecular sieve at a weight ratio of 5:1 to obtain catalyst C2.

(2) Using the same method as in Example 1 to prepare dimethyl sulfoxide, the difference is that the molar ratio of dimethyl sulfide to oxidant is 2:3, and the weight ratio of dimethyl sulfide to catalyst C2 is 2 :1, the weight ratio of the solvent to the catalyst C2 is 200:1, the reaction temperature is 40°C, the pressure in the reactor is 0.2MPa, and the volume space velocity of the reaction material is 10h ^-1 .

Wherein, the results obtained by analyzing the mixtures output from the reactor when the reaction was carried out to 0.5 hour and 6 hours respectively are listed in Table 1.

Table 1

Example 3

(1) Provide catalyst

Referring to the method disclosed in Chinese patent CN1132699C, the following method is used to prepare a hollow titanium-silicon molecular sieve, and use it as the second titanium-silicon molecular sieve:

The second titanium-silicon molecular sieve obtained in Example 1 was uniformly mixed according to the ratio of molecular sieve (in grams): sulfuric acid (in moles): water (in moles) = 100:0.15:150, and reacted at 90° C. for 5.0 hours. Then, the obtained mixture was filtered, and the collected solid matter was washed and dried at 120° C. for 2 hours to obtain an acid-treated TS-1 molecular sieve. The obtained acid-treated TS-1 molecular sieve is according to molecular sieve (in grams): triethanolamine (in moles): tetrapropylammonium hydroxide (in moles): water (in moles) = 100: 0.20: 0.15 : 180 ratio, mixed evenly, put into a stainless steel sealed reaction kettle, placed at a constant temperature of 190°C and autogenous pressure for 12 hours, after cooling and pressure relief, filter the obtained mixture, collect the solid matter and wash it, and put it at 120°C Drying for 2 hours, followed by calcination at 550° C. for 5 hours, thereby obtaining a second titanium-silicon molecular sieve with a titanium oxide content of 2.5% by weight.

The first titanium-silicon molecular sieve was prepared by the same method as the second titanium-silicon molecular sieve, the difference was that instead of roasting at 500°C, the hollow titanium-silicon molecular sieve containing the template obtained after drying at 120°C for 2 hours was used as the first titanium-silicon molecular sieve. Titanium silicate molecular sieve, the content of titanium oxide is 2.4% by weight, and the content of template agent is 7.3% by weight.

Mix the second titanium-silicon molecular sieve with the first titanium-silicon molecular sieve at a weight ratio of 5:1 to obtain catalyst C3.

(2) Using the same method as in Example 1 to prepare dimethyl sulfoxide, the difference is that the molar ratio of dimethyl sulfide to oxidant is 1:0.5, and the weight ratio of dimethyl sulfide to catalyst C3 is 50 :1, the weight ratio of solvent to catalyst C3 is 80:1, the reaction temperature is 20°C, the pressure in the reactor is 0.5MPa, and the volume space velocity of the reaction material is 2.0h ^-1 .

The obtained liquid phase mixture containing dimethyl sulfoxide is analyzed by gas chromatography, and the conversion rate of dimethyl sulfide, the effective utilization rate of the oxidant and the selectivity of dimethyl sulfoxide are calculated. Wherein, the results obtained by analyzing the mixture output from the reactor when the reaction was carried out to 0.5 hour, 6 hours and 110 hours are listed in Table 2 respectively.

Example 4

(1) A catalyst was provided by the same method as in Example 3, except that the second titanium-silicon molecular sieve and the first titanium-silicon molecular sieve were mixed at a weight ratio of 2:1, thereby obtaining catalyst C4.

(2) Dimethyl sulfoxide was prepared by the same method as in Example 3, except that the catalyst C3 was replaced by the same amount of catalyst C4.

Wherein, the results obtained by analyzing the mixture output from the reactor when the reaction was carried out to 0.5 hour, 6 hours and 110 hours are listed in Table 2 respectively.

Comparative example 3

(1) A catalyst is provided by the same method as in Example 3, except that instead of using the first titanium-silicon molecular sieve, the second titanium-silicon molecular sieve is used as the catalyst D3.

(2) Dimethyl sulfoxide was prepared by the same method as in Example 3, except that the catalyst C3 was replaced by the same amount of catalyst D3.

Wherein, the results obtained by analyzing the mixture output from the reactor when the reaction was carried out to 0.5 hour, 6 hours and 110 hours are listed in Table 2 respectively.

Comparative example 4

(1) A catalyst is provided by the same method as in Example 3, except that instead of using the second titanium-silicon molecular sieve, the first titanium-silicon molecular sieve is used as the catalyst D4.

(2) Dimethyl sulfoxide was prepared by the same method as in Example 3, except that the catalyst C3 was replaced by the same amount of catalyst D4.

Wherein, the results obtained by analyzing the mixture output from the reactor when the reaction was carried out to 0.5 hour, 6 hours and 110 hours are listed in Table 2 respectively.

Comparative example 5

Dimethyl sulfoxide was prepared by the same method as in Example 3, except that no catalyst was used.

Wherein, the results obtained by analyzing the mixture output from the reactor when the reaction was carried out to 0.5 hour are listed in Table 2.

Table 2

Example 5

(1) Provide catalyst

Refer to the method described in Zeolites, 1992, Vol.12, pages 943-950, to prepare titanium-silicon molecular sieve TS-1 and use it as the second titanium-silicon molecular sieve. The specific method is as follows.

At room temperature (20°C), mix 22.5 grams of tetraethyl orthosilicate with 10.0 grams of triethanolamine as a template, add 59.8 grams of distilled water, stir and mix, then hydrolyze at normal pressure and 60°C for 1.0 hour to obtain orthosilicon Hydrolyzed solution of tetraethyl acetate. Under vigorous stirring, a solution consisting of 1.0 g of tetrabutyl titanate and 5.0 g of anhydrous isopropanol was slowly added to the hydrolysis solution, and the resulting mixture was stirred at 75° C. for 3 hours to obtain a clear transparent colloid. The colloid was placed in a sealed stainless steel reaction vessel, and kept at a constant temperature of 170° C. for 36 hours to obtain a mixture of crystallized products. The obtained mixture was filtered, the collected solid matter was washed with water, dried at 110° C. for 60 minutes, and then calcined at 550° C. for 4 hours to obtain the second titanium silicate molecular sieve.

The first titanium-silicon molecular sieve was prepared by the same method as the second titanium-silicon molecular sieve, the difference was that instead of roasting at 500°C, the titanium-silicon molecular sieve TS-1 containing the template obtained after drying at 110°C for 60 minutes was used as The first titanium silicate molecular sieve has a titanium oxide content of 2.1% by weight and a templating agent content of 13.2% by weight.

Mix the second titanium-silicon molecular sieve and the first titanium-silicon molecular sieve at a weight ratio of 1:1 to obtain catalyst C5.

(2) Preparation of dimethyl sulfoxide

Send dimethyl sulfide, hydrogen peroxide as an oxidant, water as a solvent and catalyst C5 into a slurry bed reactor equipped with a membrane separator for oxidation reaction to obtain a mixture containing dimethyl sulfoxide. Among them, the molar ratio of dimethyl sulfide to oxidant is 1:1.5, the weight ratio of dimethyl sulfide to catalyst C5 is 10:1, the weight ratio of solvent to catalyst C5 is 5:1, and the reaction temperature is 40°C , the pressure in the reactor is 0.5MPa, and the volume space velocity of the reaction material is 25.0h ^-1 .

The reaction mixture is separated in a membrane separator into a liquid phase mixture containing dimethyl sulfoxide and a catalyst residue, and the catalyst residue is sent to the reactor for recycling.

The liquid phase mixture containing dimethyl sulfoxide was analyzed by gas chromatography, and the conversion rate of dimethyl sulfide, the effective utilization rate of oxidant and the selectivity of dimethyl sulfoxide were calculated. Wherein, the results obtained by analyzing the mixtures output from the reactor when the reaction was carried out to 0.5 hour and 6 hours respectively are listed in Table 3.

Example 6

(1) Provide catalyst

Refer to the method described in Zeolites, 1992, Vol.12, pages 943-950, to prepare titanium-silicon molecular sieve TS-1 and use it as the second titanium-silicon molecular sieve. The specific method is as follows.

At room temperature (20°C), mix 25.5 g of tetraethyl orthosilicate with 15.0 g of n-butylamine as a template, add 40.8 g of distilled water, stir and mix, then hydrolyze at normal pressure and 60°C for 1.0 hour to obtain Hydrolyzed solution of tetraethylorthosilicate. Under vigorous stirring, a solution consisting of 1.0 g of tetrabutyl titanate and 5.0 g of anhydrous isopropanol was slowly added to the hydrolysis solution, and the resulting mixture was stirred at 75° C. for 3 hours to obtain a clear transparent colloid. The colloid was placed in a sealed stainless steel reaction kettle, and kept at a constant temperature of 170° C. for 36 hours to obtain a mixture of crystallized products. The obtained mixture was filtered, the collected solid matter was washed with water, dried at 110° C. for 60 minutes, and then calcined at 550° C. for 5 hours to obtain the second titanium silicate molecular sieve.

The first titanium-silicon molecular sieve was prepared by the same method as the second titanium-silicon molecular sieve, the difference was that instead of roasting at 500°C, the titanium-silicon molecular sieve TS-1 containing the template obtained after drying at 110°C for 60 minutes was used as The first titanium silicate molecular sieve has a titanium oxide content of 2.0% by weight and a template content of 12.7% by weight.

Mix the second titanium-silicon molecular sieve and the first titanium-silicon molecular sieve at a weight ratio of 3:1 to obtain catalyst C6.

(2) Preparation of dimethyl sulfoxide

Send dimethyl sulfide, hydrogen peroxide as an oxidant, methanol as a solvent and catalyst C6 into a slurry bed reactor equipped with a membrane separator for oxidation reaction to obtain a mixture containing dimethyl sulfoxide. Among them, the molar ratio of dimethyl sulfide to oxidant is 1:0.5, the weight ratio of dimethyl sulfide to catalyst C6 is 2:1, the weight ratio of solvent to catalyst C6 is 10:1, and the reaction temperature is 50°C , the pressure in the reactor is 1.5MPa, and the volume space velocity of the reaction material is 15.0h ^-1 .

The reaction mixture is separated in a membrane separator into a liquid phase mixture containing dimethyl sulfoxide and a catalyst residue, and the catalyst residue is sent to the reactor for recycling.

The liquid phase mixture containing dimethyl sulfoxide was analyzed by gas chromatography, and the conversion rate of dimethyl sulfide, the effective utilization rate of oxidant and the selectivity of dimethyl sulfoxide were calculated. Wherein, the results obtained by analyzing the mixtures output from the reactor when the reaction was carried out to 0.5 hour and 6 hours respectively are listed in Table 3.

table 3

Examples 7-10 The following methods were used to measure the activity of titanium silicate molecular sieves.

Titanium silicon molecular sieve, 36% by weight of ammonia water (calculated as NH ₃ ), 30% by weight of hydrogen peroxide (calculated as H ₂ O ₂ ), tert-butanol and cyclohexanone by weight ratio = 1:7.5:10:7.5:10 After mixing, stir and react at 80°C for 2 hours under atmospheric pressure, filter the reactant, analyze the composition of the liquid phase by gas chromatography, and use the following formula to calculate the conversion rate of cyclohexanone and use it as the activity of titanium silicon molecular sieve ,

The conversion rate of cyclohexanone (%)=[(the molar amount of cyclohexanone added−the molar amount of unreacted cyclohexanone)/the molar amount of cyclohexanone added]×100%.

Example 7

(1) The catalyst is provided by the same method as in Example 1, except that the second titanium-silicon molecular sieve is the titanium-silicon molecular sieve TS-1 unloaded from the ammoximation reaction process of cyclohexanone at a temperature of 550° C. Calcined in an air atmosphere for 4 hours, the activity was 40%, and the fresh activity was 95%. The second titanium-silicon molecular sieve was mixed with the first titanium-silicon molecular sieve in the same proportion as in Example 1 to obtain catalyst C7.

(2) Dimethyl sulfoxide was prepared by the same method as in Example 1, except that the catalyst C1 was replaced by the same amount of catalyst C7.

The liquid phase mixture containing dimethyl sulfoxide was analyzed by gas chromatography, and the conversion rate of dimethyl sulfide, the effective utilization rate of oxidant and the selectivity of dimethyl sulfoxide were calculated. Wherein, the results obtained by analyzing the mixture output from the reactor when the reaction was carried out to 0.5 hour, 6 hours and 110 hours are listed in Table 4 respectively.

Example 8

(1) The catalyst is provided by the same method as in Example 3, except that the second titanium-silicon molecular sieve is the hollow titanium-silicon molecular sieve unloaded from the phenol hydroxylation reaction device and calcined in an air atmosphere at a temperature of 570°C It was obtained at 4 hours and had an activity of 30%, compared with 96% when fresh. The second titanium-silicon molecular sieve was mixed with the first titanium-silicon molecular sieve in the same proportion as in Example 3, thereby obtaining catalyst C8.

(2) Dimethyl sulfoxide was prepared by the same method as in Example 3, except that the catalyst C3 was replaced by the same amount of catalyst C8.

The liquid phase mixture containing dimethyl sulfoxide was analyzed by gas chromatography, and the conversion rate of dimethyl sulfide, the effective utilization rate of oxidant and the selectivity of dimethyl sulfoxide were calculated. Wherein, the results obtained by analyzing the mixture output from the reactor when the reaction was carried out to 0.5 hour, 6 hours and 110 hours are listed in Table 4 respectively.

Example 9

(1) The catalyst is provided by the same method as in Example 6, except that the second titanium-silicon molecular sieve is a hollow titanium-silicon molecular sieve discharged from the propylene epoxidation reaction device in an air atmosphere at a temperature of 570°C Calcined for 4 hours, the activity was 12%, and the activity was 96% when fresh. The second titanium-silicon molecular sieve was mixed with the first titanium-silicon molecular sieve in the same proportion as in Example 6, thereby obtaining catalyst C9.

(2) Dimethyl sulfoxide was prepared by the same method as in Example 6, except that the catalyst C6 was replaced by the same amount of catalyst C9.

The liquid phase mixture containing dimethyl sulfoxide was analyzed by gas chromatography, and the conversion rate of dimethyl sulfide, the effective utilization rate of oxidant and the selectivity of dimethyl sulfoxide were calculated. Wherein, the results obtained by analyzing the mixture output from the reactor at 0.5 hour, 6 hours and 110 o'clock are listed in Table 4 respectively.

Example 10

(1) The catalyst is provided by the same method as in Example 3, the difference is that the second titanium-silicon molecular sieve is made of (A) the hollow titanium-silicon molecular sieve unloaded from the propylene epoxidation reaction device at a temperature of 570 ° C in The regenerant obtained by roasting in an air atmosphere for 4 hours has an activity of 48%, and an activity of 96% when fresh; and (B) the composition of the hollow titanium-silicon molecular sieve prepared by the same method as in Example 3, wherein the regenerated The weight ratio of titanium-silicon molecular sieve prepared by the same method as in Example 3 was 1:1. The second titanium-silicon molecular sieve was mixed with the first titanium-silicon molecular sieve in the same proportion as in Example 3 to obtain catalyst C10.

(2) Dimethyl sulfoxide was prepared by the same method as in Example 3, except that the catalyst C3 was replaced by the same amount of catalyst C10.

The liquid phase mixture containing dimethyl sulfoxide was analyzed by gas chromatography, and the conversion rate of dimethyl sulfide, the effective utilization rate of oxidant and the selectivity of dimethyl sulfoxide were calculated. Wherein, the results obtained by analyzing the mixture output from the reactor when the reaction was carried out to 0.5 hour, 6 hours and 110 hours are listed in Table 4 respectively.

Table 4

Claims (12)

1. the method preparing dimethyl sulfoxide, the method is included under oxidation reaction condition, by two Dimethyl sulfide contacts with HTS with at least one oxidant, and wherein, described HTS contains First HTS and the second HTS, described first HTS contains template, described Second HTS does not contains template, on the basis of the total amount of described HTS, described first titanium The content of si molecular sieves is 15-50 weight %, and the content of described second HTS is 50-85 weight %, in described first HTS, the content of template is 5-15 weight %.

Method the most according to claim 1, wherein, described template is quaternary ammonium base, aliphatic One or more in amine and aliphatic hydramine.

Method the most according to claim 1, wherein, the most described second HTS For through regeneration the reaction unit using HTS as catalyst draw off agent.

Method the most according to claim 3, wherein, described in draw off agent be Ammoximation reaction device Draw off agent, hydroxylating device draw off agent and the one drawing off in agent of epoxidation reaction device or Multiple.

Method the most according to claim 3, wherein, in described second HTS, through again The content drawing off agent of the raw reaction unit using HTS as catalyst is for 5-100 weight %.

Method the most according to claim 1, wherein, dimethyl sulfide and described HTS Weight ratio be 0.1-50:1.

Method the most according to claim 1, wherein, described contact exists at least one solvent Under carry out, the weight ratio of described solvent and dimethyl sulfide is 0.1-1000:1.

Method the most according to claim 7, wherein, described solvent is selected from water, C₁-C₆Alcohol, C₃-C₈Ketone and C₂-C₆Nitrile.

Method the most according to claim 1, wherein, dimethyl sulfide and the mol ratio of oxidant For 1:0.1-2.

10. according to the method described in claim 1 or 9, wherein, described oxidant is peroxide.

11. methods according to claim 10, wherein, described oxidant selected from hydrogen peroxide, Tert-butyl hydroperoxide, dicumyl peroxide, cyclohexyl hydroperoxide, peracetic acid and Perpropionic Acid.

12. methods according to claim 1, wherein, described oxidation reaction condition includes: temperature For 0-100 DEG C；And in terms of gauge pressure, pressure is 0-3MPa.