CN104001544A - Catalytic oxidation desulfurization catalyst and preparation method thereof - Google Patents

Abstract

The invention discloses a catalytic oxidation desulfurization catalyst and a preparation method thereof. The expression is (C _n -C _s -C _n ) ₂ ·Y·(XM ₁₂ O ₄₀ ), wherein C _n -C _s -C _n is a gemini surfactant, the spacer s=2, 4 or 6, and the alkyl chain n=14, 16 or 18; the counter anion atom Y is a halogen atom; the heteroatom X is phosphorus, silicon, boron, iron, cobalt , arsenic or germanium; the coordination atom M is molybdenum or tungsten. The invention is not only applicable to the oxidative desulfurization of sulfur-containing organic matter, but also can extend the emulsion to other fields of organic synthesis, such as olefin epoxidation, alcohol oxidation, acid catalysis, isomerization and other reactions. As long as the system is carried out in an oil-water two-phase, it is possible to form a catalyst with high catalytic efficiency with a suitable heteropolyacid, a suitable alkyl chain length, and a suitable spacer length. The catalyst can be separated by demulsification, and its catalytic efficiency can still maintain 95.7% of the original catalytic efficiency after being reused ten times.

Description

Catalytic oxidation desulfurization catalyst and preparation method thereof

technical field

The invention relates to a recyclable emulsion catalytic system for the oxidation of organic sulfides and a preparation method thereof, in particular to a recyclable and reusable catalytic system prepared from gemini surfactants and polyacid compounds as raw materials Catalytic oxidation desulfurization catalyst and its preparation method.

Background technique

Ultra-deep desulfurization of gasoline and diesel has become one of the urgent research topics in the world. The sulfur compounds in fuel oil are inevitably released into the air in the form of gas during the combustion process. These oxidizing gases react with moisture in the air to form sulfate, which in turn forms acid rain, damages buildings, acidifies soil, causes forest degradation, and destroys ecosystems. Therefore, it is of great significance to develop ultra-deep desulfurization of diesel oil. Ultra-deep desulfurization of gasoline and diesel is not only for the production of clean fuels, but also has potential applications in the production of sulfide-free hydrogen for fuel cells.

Desulfurization technologies that are considered very attractive include extraction separation or adsorption, selective oxidation desulfurization, and biological desulfurization. Oxidative desulfurization usually consists of two main steps: the first step is to oxidize the sulfide in the fuel oil, and the second step is to separate and remove the oxidized sulfide from the fuel oil by extraction, adsorption, distillation and other methods. Since oxidative desulfurization does not require a hydrogen source, compared with other hydrodesulfurization processes, the investment is less. In addition, the investment in reaction temperature, pressure and equipment required for oxidative desulfurization is far lower than that of hydrodesulfurization processes.

Sulfur and oxygen have many similar properties. Organic sulfides exhibit properties very similar to their corresponding hydrocarbons, and their solubility in water and solvents is almost identical. Organic oxides show stronger solubility than organic sulfides in organic solvents. If oxygen molecules are attached to the sulfur atoms of these sulfides, their polarity will be greatly enhanced, resulting in a higher solubility in polar solvents. Solubility increases. A large number of studies have shown that the dipole moment of the molecule can be greatly increased after the sulfide in diesel is reacted with the oxidant, and the sulfide is converted into the corresponding sulfone and sulfoxide, and the polarity is increased, which can greatly improve the extraction (or adsorption). ) desulfurization efficiency. Hydrogen peroxide is a very promising oxidizing agent. The biggest obstacle for hydrogen peroxide as a catalyst is the mixing problem. Hydrogen peroxide exists in the water phase, but sulfide exists in the organic phase.

Emulsion is an important type of dispersion system, which is widely used in energy, chemical industry, food, medicine, pesticide, cosmetics and other fields. In the liquid-liquid two-phase system, the reaction rate of the oxidation process is determined not only by the intrinsic reaction rate of the reaction, but also by the mass transfer rate. In order to make them better mixed, researchers have adopted a variety of measures, such as adding surfactants, accelerating stirring, ultrasonic emulsification and so on. Generally speaking, the oxidative desulfurization reaction of hydrogen peroxide as an oxidant is a liquid-liquid two-phase reaction, but the disadvantage of the two-phase system is that the reaction rate is slow. A widely accepted method is the addition of surfactants, which dissolve in the reagent or form a milky dispersion. In the emulsion system, the colloidal particles formed by surfactant molecules provide a large specific surface area required for the reaction, and the steric hindrance effect caused by mass transfer is greatly reduced, so the emulsion or microemulsion system can effectively increase the reaction rate. In addition, in principle, by changing the reaction temperature, the water-oil ratio, and the HLB value of the surfactant, the surfactant can be dispersed on the surface of the emulsion droplet and remain stable during the reaction. After the reaction, the emulsion droplet can be broken. , Surfactant gathers on the interface of water and oil two phases, so it is easy to separate and reuse.

Commonly used surfactants are octadecyltrimethylammonium bromide (STAB) and dioctadecyldimethylammonium bromide (DODA). These surfactants have a single positive charge center and have one or two alkyl chains. In the catalyst structure synthesized by this type of surfactant, the density of the alkyl chain at the catalytic active center is either too low or too high, and it is impossible to simultaneously take into account the formation of the active peroxygen center and the contact catalytic center of the low-polarity sulfide. According to previous literature and patent reports, when the density of alkyl chain-wrapped polyacids is low, although it is beneficial for hydrogen peroxide to contact polyacids to form active catalytic centers, it is not conducive to the contact between low-polarity sulfur-containing organics and catalysts, reducing the The catalytic ability of the catalyst; when the density of the alkyl chain-wrapped polyacid is high, it will seriously hinder the oxidant from oxidizing the heteropolyacid to peroxopolyacid, and it is also not conducive to improving the catalytic activity of the catalyst. Therefore, the preparation of a polyacid hybrid material with a reasonable packing density and order of alkyl chains, whose structure can skillfully balance the formation of peroxygen centers and the diffusion of low-polarity sulfides, is an important way to improve the catalytic oxidation desulfurization of polyacid groups. One of the research hotspots of catalysts.

Contents of the invention

The purpose of the present invention is to provide a catalytic oxidation desulfurization catalyst and its preparation method, the catalytic system can efficiently remove sulfur in sulfur-containing organic matter in the emulsion, and the catalyst is easy to separate and recover from the product.

The purpose of the present invention is achieved through the following technical solutions:

A catalyst for catalytic oxidative desulfurization, using Gemini surfactants to wrap H ₃ XM ₁₂ O ₄₀ polyacids with Keggin structure to form (XM ₁₂ C ₁₈ C _n : n=2,4,6) heteropolyacid complexes and finally prepared as a catalyst with the expression (C _n -C _s -C _n ) ₂ ·Y·(XM ₁₂ O ₄₀ ), wherein C _n -C _s -C _n is a gemini synthesized according to the literature in the present invention Surfactant, spacer s=2, 4 or 6, alkyl chain n=14, 16 or 18. Heteropolyanions are compounds with Keggin structure or vacant Keggin structure or derivatives thereof, the counter anion atom Y is a halogen atom, such as Br, Cl, etc., and the heteroatom X is phosphorus, silicon, boron, iron, cobalt, arsenic, Germanium, etc., the coordination atom M is molybdenum or tungsten.

The above-mentioned catalyst is mainly used in an emulsion catalytic system, and the system uses water as a solvent, 30% hydrogen peroxide as an oxidant, and a compound of a heteropolyacid salt as a catalyst for desulfurization catalysis.

Above-mentioned catalytic system is used for the synthetic method of catalytic oxidation desulfurization catalyst, and its main steps are:

1) Synthesize C _n -C _s -C _n type gemini surfactant (alkyl chain n = 14, 16, 18; spacer s = 2, 4, 6) according to the literature: 4.5-7 mmol of N, N , N,N-Tetramethylethylenediamine was added dropwise to 4-8mmol ethanol solution of halogenated hydrocarbons containing 2,4,6 alkyl chains, then stirred at 40-100°C for 48-72h, and then used drying with a rotary evaporator, and finally crystallizing in a mixed solvent of chloroform/ethyl acetate to obtain a C _n -C _s -C _n type gemini surfactant;

2) Dissolving the _Cn - _Cs - _Cn type gemini surfactant prepared in 1.5-3mmola) with 40-70mL of ethanol. Then slowly add 0.5-2mmol, 5-30mg/mL H ₃ XM ₁₂ O ₄₀ ethanol solution dropwise, stir for 6-24h, then filter with suction, wash with ethanol and deionized water repeatedly for 3 times, and finally get a new type of gemini surfactant The composite catalyst XM ₁₂ C ₁₈ C _n (n=2,4,6) of agent and polyacid, dry for subsequent use;

3) Put the solvent, model oil and oxidant into a round-bottomed flask reactor with a reflux device, then add the reactants and the multi-acid composite catalyst XM ₁₂ C ₁₈ C _n , and then rotate at 40-80°C and 400-1000rpm Under stirring, an emulsion is formed; wherein the ratio of oxidant/reactant/catalyst is 20-25/1-3/0.01-0.015. Utilize thin-layer chromatography and gas chromatography to monitor the consumption of sulfide to judge the reaction end point, the reaction time is between 20-115 minutes, and the stirring is stopped.

4) After the reaction is finished, by standing still, the water and oil are separated, and then the catalyst is extracted by suction filtration. The extracted crude catalyst is cleaned with ethanol for 3-5 times, then dried in a vacuum oven, and finally a composite catalyst XM ₁₂ C ₁₈ C _n (n=2,4 , 6).

In the above method, the reactants are mainly organic sulfur compounds, including but not limited to thiophene, benzothiophene, dibenzothiophene and 4,6-dimethyldibenzothiophene, dimethyl sulfide, diethyl sulfur etc.

In the above method, the Gemini surfactant is C ₁₈ -C ₂ -C ₁₈ , C ₁₈ -C ₄ -C ₁₈ , C ₁₈ -C ₆ -C ₁₈ , and its preparation method is as follows:

Preparation of C ₁₈ -C ₂ -C ₁₈ : Add bromooctadecane (1.834g, 5.5mmol, 1equiv) to a 100ml round bottom flask, drop N,N,N,N-tetramethylethylenedi Amine (0.745ml, 5mmol, 0.9equiv), using 50ml of ethanol as a solvent, and heated to reflux in an oil bath at 80°C, reacted for 48-72h. After the reaction, the organic solvent was evaporated to dryness under reduced pressure, and then recrystallized more than three times using a mixed solvent of chloroform/ethyl acetate to obtain 1.33 g of a white solid with a yield of 55%.

Preparation of C ₁₈ -C ₄ -C ₁₈ : Add N,N-dimethyloctadecylamine (1.64 g, 5.5 mmol, 1 equiv) and 1,4-dibromobutane (1.08 g, 5 mmol, 0.9 equiv) To a 100ml round bottom flask, add 50ml of ethanol solution as a solvent, heat to reflux in an oil bath at 80°C, and react for 48-72h. After the reaction was completed, the organic solvent was evaporated to dryness under reduced pressure, washed twice with ethyl acetate, and then recrystallized more than three times with a mixed solvent of chloroform/ethyl acetate to obtain 1.66 g of a white solid with a yield of 61%.

Preparation of C ₁₈ -C ₆ -C ₁₈ : Add N,N-dimethyloctadecylamine (1.64 g, 5.5 mmol, 1 equiv) and 1,6-dibromohexane (1.27 g, 5 mmol, 0.9 equiv) To a 100ml round bottom flask, add 50ml of ethanol solution as a solvent, heat to reflux in an oil bath at 80°C, and react for 48-72h. After the reaction was completed, the organic solvent was evaporated to dryness under reduced pressure, washed twice with ethyl acetate, and then recrystallized more than three times with a mixed solvent of chloroform/ethyl acetate to obtain 1.97 g of a white solid with a yield of 60%.

In the above method, the catalyst may be (C ₁₈ -C ₂ -C ₁₈ ) ₂ ·Br·(AsMo ₁₂ O40), (C ₁₈ -C ₄ -C ₁₈ ) ₂ ·Br·(AsMo ₁₂ O40), (C ₁₈ -C ₆ -C ₁₈ ) ₂ ·Br·(AsMo ₁₂ O40), (C ₁₈ -C ₂ -C ₁₈ ) ₂ ·Br·(AsW ₁₂ O40), (C ₁₈ -C ₂ -C ₁₈ ) ₂ ·Br·(PMo ₁₂ O40), (C ₁₈ -C ₂ -C ₁₈ ) ₂ ·Br·(PW ₁₂ O40).

In the above method, the heteroatom X can be phosphorus, silicon, boron, iron, cobalt, arsenic, germanium, etc., and the coordination atom M can be molybdenum or tungsten.

In the above method, the oxidizing agent is hydrogen peroxide.

In the above method, the solvent is deionized water.

In the above method, the model oil is mainly non-polar alkane, and other organic matter immiscible with solvents and reactants; the non-polar alkane is hexadecane, tetradecane, dodecane, n-octane, n-hexane, etc.

The catalytic system of the present invention includes two-phase liquid immiscible, amphiphilic catalyst and reactants when catalyzing the oxidation of organic molecules. The amphiphilic catalyst self-assembles at the two-phase interface, the hydrophobic alkyl chain points to the oil phase, the catalytic center points to the water phase, and the oxidation reaction occurs at the interface of the two phases. After the reaction is completed, the reaction emulsion can be allowed to stand still and the two phases are separated, while the catalyst is insoluble in the two phases or the product, and the catalyst is easy to separate and recover from the product, which can realize multiple repetitions and recycling.

Amphiphilic catalysts are combined by electrostatic attraction between a surfactant with a positive charge center and a heteropolyacid salt with a negative charge center. Generally, heteropolyacids have strong hydrophilicity, and the hydrophilic-hydrophobic balance of the catalyst can be adjusted according to the characteristics of the reaction system by the number of modified organic molecules or the type and carbon chain length of the surfactant functional group, so as to achieve amphiphilic sexual design. The selected surfactant can be an ionic surfactant, a nonionic surfactant or a polymer surfactant according to different actual needs.

The difference with the reported documents and patents is that the surfactant involved in the present invention is a gemini type surfactant with a double positive charge center, a spacer and a double alkyl chain that can be regulated, and its expression is C _n -C _s -C _n . The double charge center can regulate the packing density of the alkyl chain around the polyacid catalytic center, the length of the alkyl chain n can adjust the hydrophobicity of the gemini surfactant, and the length of the intermediate spacer can realize the stacking order of the alkyl chain In order to achieve the purpose of more efficient regulation of catalyst performance. Compared with surfactants with a single positive charge center, gemini surfactants can be arranged more regularly on the surface of heteropolyacid salts, and the appropriate alkyl chain packing density can also effectively balance the entry of hydrogen peroxide to form active peroxygen Species, and improve the contact and reaction between the sulfur-containing organic matter and the peroxopolysalt formed in the reaction process, thereby improving the overall catalytic efficiency and catalytic selectivity of the catalyst. In addition, since what is involved in the present invention is an emulsion catalytic system, the reaction occurs at the phase interface. Due to the high specific surface area of the dispersed phase, the emulsion catalytic system is very similar to the homogeneous catalytic reaction.

In the catalytic oxidation desulfurization reaction system involved in the present invention, the solvent used is water instead of toxic halogenated hydrocarbons or aromatic hydrocarbons, and the process is green and environment-friendly. After the reaction is completed, the demulsification can be completed only by standing still, the reaction liquid is separated, the catalyst is insoluble in any phase, and the repeated reuse of the catalysis can be completed by simple suction filtration and washing. The experimental results also show that this The catalyst prepared by the invention has good cycle stability. After being reused ten times, its catalytic efficiency can still maintain 95.7% of the original catalytic efficiency, and the catalyst can completely remove dibenzothiophene in the system within 20-30 minutes. In the emulsion system formed by the above-mentioned catalysts, the special molecular structure of the gemini-type surfactant skillfully balances the formation of peroxopolyacid salts, and the formation of benzothiophene, dibenzothiophene, 4,6-dimethyldibenzo The adsorption of low-polarity sulfur-containing organic compounds such as thiophene improves the catalytic activity of the catalyst.

The invention is not only applicable to the oxidative desulfurization of sulfur-containing organic matter, but also can extend the emulsion to other fields of organic synthesis, such as olefin epoxidation, alcohol oxidation, acid catalysis, isomerization and other reactions. As long as the system is carried out in an oil-water two-phase, it is possible to form a catalyst with high catalytic efficiency with a suitable heteropolyacid, a suitable alkyl chain length, and a suitable spacer length. The catalyst can be separated by demulsification and recycled.

The present invention has the following advantages:

1. The present invention relates to a surfactant with a double positive charge center, which can not only regulate the oxidation performance of the catalyst by changing the composition of the heteropolyacid, but also regulate the length of the alkyl chain in the gemini surfactant , the length of the spacer, to more effectively realize the design and assembly of the catalyst at the molecular level;

2. Compared with surfactants with a single positive charge center, gemini surfactants can not only better regulate the hydrophobicity of the catalyst, but also arrange more regularly on the surface of the heteropolyacid salt to regulate the surface of the catalytic center. Alkyl chain density, thereby improving the contact and reaction between the sulfur-containing organic matter and the peroxopolysalt formed during the reaction, thereby improving the overall catalytic efficiency and catalytic selectivity of the catalyst;

3. In the emulsion system involved in the present invention, the reaction occurs at the two-phase interface and has a higher specific surface area, so that the reaction rate is similar to the homogeneous catalytic reaction;

4. After the catalytic reaction is over, demulsification can be achieved only through physical static methods, so as to realize the separation and recycling of catalysts and reactants;

5. The present invention is not only applicable to the oxidative desulfurization of sulfur-containing organic matter, but also can select suitable heteropolyacids and gemini-type surfactants suitable for the length of the alkyl chain and the length of the spacer according to the actual needs of the catalytic reaction type. It is possible to form catalysts with high catalytic efficiency.

Description of drawings

Figure 1 shows the reaction time required for AsMo ₁₂ C ₁₈ C ₂ to completely remove DBT under different input amounts of hydrogen oxide;

Figure 2 is the reaction time for AsMo ₁₂ C ₁₈ C ₂ to completely remove DBT at different temperatures;

Figure 3 shows the reaction time for complete removal of DBT by different (C ₁₈ -C ₂ -C ₁₈ ) ₂ ·Br·(AsMo ₁₂ O40);

Fig. 4 is the variation curve of DBT conversion amount with reaction time;

Fig. 5 is the variation curve of ln(C _t /C ₀ ) with the reaction time;

Fig. 6 is the conversion rate of (C ₁₈ -C ₂ -C ₁₈ ) ₂ ·Br·(AsMo ₁₂ O ₄₀ ) catalyzing the same content of BT and the change curve of ln(C _t /C ₀ ) with time;

Figure 7 shows the conversion rate of 4,6-DMBT and the change curve of ln(C _t /C ₀ ) over time with the same content of (C ₁₈ -C ₂ -C ₁₈ ) ₂ ·Br·(AsMo ₁₂ O ₄₀ ) catalyst ;

Figure 8 is the time corresponding to the complete catalysis of DBT conversion by different catalysts;

Figure 9 shows the amount of conversion of DBT catalyzed by the catalyst within 25 minutes of different cycle times.

Detailed ways

The technical solution of the present invention will be further described below in conjunction with the accompanying drawings, but it is not limited to this. Any modification or equivalent replacement of the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention should be covered by the technical solution of the present invention. in the scope of protection.

Example 1

Preparation of catalyst (C ₁₈ -C ₂ -C ₁₈ ) ₂ ·Br·(AsMo ₁₂ O ₄₀ ):

As an illustrative example, the catalyst (C ₁₈ -C ₂ -C ₁₈ ) ₂ ·Br·(AsMo ₁₂ O ₄₀ ) can be prepared by dissolving 5.5 mmol of 1-bromooctadecane in 50 mL of ethanol solution, and then Slowly add 5 mmol of N,N,N,N-tetramethylethylenediamine dropwise, then stir and heat in an oil bath at 80°C for 48h, and finally evaporate to dryness with a rotary evaporator, and dissolve in the chloroform/ethyl acetate system Crystallize to get C ₁₈ -C ₂ -C ₁₈ ; Dissolve 0.096mmol of C ₁₈ -C ₂ -C ₁₈ in 5mL of ethanol solution, then slowly add 0.048mmol of H ₃ AsMo ₁₂ O ₄₀ to get bright yellow Precipitate (C ₁₈ -C ₂ -C ₁₈ ) ₂ ·Br·(AsMo ₁₂ O ₄₀ ) (referred to as AsMo ₁₂ C ₁₈ C ₂ ), then reacted for 12 hours, and finally obtained AsMo ₁₂ by suction filtration, washing and drying C ₁₈ C ₂ , about 62% yield. During the reaction, the molar ratio of C ₁₈ -C ₂ -C ₁₈ to H ₃ AsMo ₁₂ O ₄₀ is 2:1. According to the principle of charge balance and molecular structure matching, a negative 3-valent polyacid anion needs 2 positive 2-valent anions The cationic Gemini molecules are balanced, and the insufficient negative charge is supplemented by a halogen anion.

Example 2

As an illustrative example, the preparation of the catalyst (C ₁₈ -C ₄ -C ₁₈ ) ₂ ·Br·(AsMo ₁₂ O ₄₀ ):

Same as Example 1, using N,N-dimethyloctadecylamine acetate, 1,4-dibromoalkane, H ₃ AsMo ₁₂ O ₄₀ to synthesize (C ₁₈ -C ₄ -C ₁₈ ) ₂ ·Br · (AsMo ₁₂ O ₄₀ ).

Dissolve 5.5mmol of 1,4-dibromoalkane in 50mL of ethanol solution, then slowly add 5mmol of N,N,N,N-tetramethylethylenediamine dropwise, then stir and heat in an oil bath at 80°C 48h, and finally evaporated to dryness with a rotary evaporator, and crystallized in a chloroform/ethyl acetate system to obtain C ₁₈ -C ₄ -C ₁₈ ; the obtained 0.096 mmol of C ₁₈ -C ₄ -C ₁₈ was dissolved in 5 mL of ethanol solution , then slowly add 0.048mmol of H ₃ AsMo ₁₂ O ₄₀ to obtain a bright yellow precipitate, then react for 12h, and finally obtain (C ₁₈ -C ₄ -C ₁₈ ) ₂ ·Br by suction filtration, washing and drying · (AsMo ₁₂ O ₄₀ ).

Example 3

As an illustrative example, the preparation of the catalyst (C ₁₈ -C ₆ -C ₁₈ ) ₂ ·Br·(AsMo ₁₂ O ₄₀ ):

Same as Example 1, using N,N-dimethyloctadecylamine acetate, 1,4-dibromohexane, H ₃ AsMo ₁₂ O ₄₀ to synthesize (C ₁₈ -C ₆ -C ₁₈ ) ₂ ·Br · (AsMo ₁₂ O ₄₀ ).

Dissolve 5.5mmol of 1,4-dibromohexane in 50mL of ethanol solution, then slowly add 5mmol of N,N,N,N-tetramethylethylenediamine dropwise, then stir and heat in an oil bath at 80°C 48h, and finally evaporated to dryness with a rotary evaporator, and crystallized in a chloroform/ethyl acetate system to obtain C ₁₈ -C ₆ -C ₁₈ ; the obtained 0.096 mmol of C ₁₈ -C ₆ -C ₁₈ was dissolved in 5 mL of ethanol solution , then slowly add 0.048mmol of H ₃ AsMo ₁₂ O ₄₀ to obtain a bright yellow precipitate, then react for 12h, and finally obtain (C ₁₈ -C ₆ -C ₁₈ ) ₂ ·Br by suction filtration, washing and drying · (AsMo ₁₂ O ₄₀ ).

Example 4

As an illustrative example, the preparation of the catalysts (STAB) ₃ AsMo ₁₂ O ₄₀ and (DODA) ₃ AsMo ₁₂ O ₄₀ for the control experiments:

Dissolve (0.144mmol) octadecyltrimethylammonium bromide (STAB) or dioctadecyldimethylammonium bromide (DODA) in 5mL ethanol solution, then slowly add 10mL (90mg, 0.048 mmol) of H ₃ AsMo ₁₂ O ₄₀ to obtain a bright yellow precipitate, then reacted for 12 hours, and finally obtained (STAB) ₃ AsMo ₁₂ O ₄₀ , (DODA) ₃ AsMo ₁₂ by suction filtration, washing with deionized water, and drying O ₄₀ .

Example 5

The purpose of this embodiment is in order to study the analysis method of model oil sulfur content:

We will benzothiophene (BT), dibenzothiophene (DBT), 4,6-dimethyldibenzothiophene (4,6-DMDBT) these three compounds, with n-hexane as solvent, configure different concentrations of Model oil, using Tianmei GC7900 gas chromatograph system (GC), draws a standard curve for each compound. Gas phase detection adopts the method of temperature programming, and the column is SE-54 capillary gas chromatography column. The detection parameters of benzothiophene (BT) are: inlet temperature 250°C, column oven temperature 150°C, detector temperature 250°C. The heating program is as follows: 5°C/min to 190°C and hold for 2 minutes, 5°C/min to 250°C and hold for 25 minutes, and the peak time is 4.3 minutes. The detection parameters of dibenzothiophene (DBT) are: the temperature of the injection port is 250°C, the temperature of the column oven is 210°C, and the temperature of the detector is 250°C. The heating program is as follows: 5°C/min to 230°C and hold for 5 minutes, 5°C/min to 250°C and hold for 25 minutes, and the peak eruption time is 6.46 minutes. The detection parameters of 4,6-dimethyldibenzothiophene (4,6-DMDBT) are: the temperature of the injection port is 250°C, the temperature of the column oven is 220°C, and the temperature of the detector is 250°C. The heating program is as follows: 5°C/min to 230°C and hold for 3 minutes, 5°C/min to 250°C and hold for 25 minutes, and the peak time is 8.6 minutes.

Example 6

The purpose of this example is to study the influence of different oxidant concentrations on the catalytic efficiency.

Take five groups of 3.13μmol (C ₁₈ -C ₂ -C ₁₈ ) ₂ ·Br·(AsMo ₁₂ O ₄₀ ) and 1527ppm DBT into a 50mL round bottom flask, and then add 0.1, 0.2, 0.4, 0.6, 0.8mL30 % H ₂ O ₂ solution, the reaction solution was reacted in an oil bath at 60°C and 800rpm/min. During the reaction, samples were taken at regular intervals, and then analyzed by concentration and gas chromatography. The test results of different oxidant concentrations are listed in Fig. 1.

As can be seen from Figure 1, when the content of hydrogen peroxide is 0.6mL, the corresponding reaction time is the shortest 25min.

Example 7

The purpose of this example is to study the influence of different reaction temperatures on the catalytic efficiency.

Take 3.13 μmol (C ₁₈ -C ₂ -C ₁₈ ) ₂ ·Br·(AsMo ₁₂ O ₄₀ ) and 1527 ppm DBT into a 50 mL round bottom flask, then add 0.6 mL of 30% H ₂ O ₂ solution, the reaction solution React under the conditions of 40, 50, 60, 70, 80°C oil bath and 800rpm/min. During the reaction, samples were taken at regular intervals, and then concentration analysis and gas chromatography analysis were performed on it. The test results of different reaction temperatures are shown in Fig. 2 .

It can be seen from Figure 2 that in the range of 40-70°C, the reaction time decreases with the increase of the reaction temperature, but when the reaction temperature continues to increase to 80°C, the reaction time increases again. When the reaction temperature is 70°C, the reaction time is 20 minutes.

Example 8

The purpose of this example is to study the influence of different catalyst contents on the catalytic efficiency.

Take 6, 8, 10, 15, 20 mg of (C ₁₈ -C ₂ -C ₁₈ ) ₂ ·Br·(AsMo ₁₂ O ₄₀ ) respectively into five two-necked round bottom flasks, and then add Reactant 271μmol DBT, 50mL n-hexane, 0.6mL30% H ₂ O ₂ solution, the reaction solution was reacted in an oil bath at 60°C, under the conditions of 800rpm/min, during the reaction, samples were taken at regular intervals, and then Concentration analysis and gas chromatography analysis were carried out on it, and the test results of five catalysts with different spacers are listed in Figure 3.

It can be seen from Figure 3 that with the increase of (C ₁₈ -C ₂ -C ₁₈ ) ₂ ·Br·(AsMo ₁₂ O ₄₀ ), the catalytic reaction time becomes shorter.

Example 9

The purpose of this example is to study the influence of different spacer lengths in gemini surfactants on the catalytic efficiency.

Take (C ₁₈ -C ₂ -C ₁₈ ) ₂ ·Br·(AsMo ₁₂ O ₄₀ ), (C ₁₈ -C ₄ -C ₁₈ ) ₂ ·Br·(AsMo ₁₂ O ₄₀ ), (C ₁₈ -C ₆ - C ₁₈ ) ₂ ·Br·(AsMo ₁₂ O ₄₀ ) 3.13 μmol each were added to three double-necked round bottom flasks, and then 271 μmol of DBT, 50 mL of n-hexane and 0.6 mL of 30% H ₂ were added to each flask O ₂ solution, the reaction solution was reacted in an oil bath at 60°C and 800rpm/min. During the reaction, samples were taken at regular intervals, and then analyzed by concentration and gas chromatography. The test results of the catalysts are listed in Fig. 4-5.

It can be seen from Figure 4-5 that with the increase of the spacer, the reaction time gradually increases, and the catalytic efficiency is the highest when the spacer is 2 methylene groups.

Example 10

The purpose of this example is to comparatively study the comparison of the catalytic efficiency of the catalyst of the present invention to different reaction substrates.

Take 3.13μmol (C ₁₈ -C ₂ -C ₁₈ ) ₂ ·Br·(AsMo ₁₂ O ₄₀ ), 1572ppm BT and 1572ppm 4,6-DMBT respectively into a 50mL round bottom flask, and then add 0.6mL of 30% H ₂ O ₂ solution, the reaction solution is reacted in an oil bath at 60°C and 800rpm/min. During the reaction, samples are taken at regular intervals, and then concentration analysis, gas chromatography analysis, and testing of different reactants are carried out. The results are presented in Figures 6-7.

Example 11

The purpose of this example is to study the comparison between the catalytic efficiency of the catalyst of the present invention and the commonly used catalysts in the literature and patents.

Take 3.13 μmol (C ₁₈ -C ₂ -C ₁₈ ) ₂ ·Br·(AsMo ₁₂ O ₄₀ ), (C ₁₈ -C ₄ -C ₁₈ ) ₂ ·Br·(AsMo ₁₂ O ₄₀ ), (C ₁₈ -C ₆ -C ₁₈ ) ₂ ·Br·(AsMo ₁₂ O ₄₀ ), (STAB) ₃ AsMo ₁₂ O ₄₀ , (DODA) ₃ AsMo ₁₂ O ₄₀ were added to five round bottom flasks respectively, and then the reaction 271 μmol of DBT, 50 mL of n-hexane, 0.6 mL of 30% H ₂ O ₂ solution, and the reaction solution was reacted in an oil bath at 60° C. at 800 rpm/min. During the reaction process, samples were taken at regular intervals, and then analyzed by concentration and gas chromatography. The test results of the three catalysts are shown in Figure 8.

It can be seen from Figure 8 that under the same conditions, (C ₁₈ -C ₂ -C ₁₈ ) ₂ ·Br·(AsMo ₁₂ O ₄₀ ), (C ₁₈ -C ₄ -C ₁₈ ) ₂ ·Br·(AsMo ₁₂ O ₄₀ )(C ₁₈ -C ₆ -C ₁₈ ) ₂ ·Br·(AsMo ₁₂ O ₄₀ ), the catalytic efficiency is significantly higher than that of commonly used catalysts (STAB) ₃ AsMo ₁₂ O ₄₀ and (DODA) ₃ AsMo ₁₂ O ₄₀ .

Example 12

The purpose of this example is to study the recyclability of the catalyst.

Take the oil phase after emulsion layering and the solid catalyst layer in the middle, and directly add them into a two-necked round-bottomed flask without any _treatment , add 271 μmol of DBT, 50 mL of n-hexane, and 0.6 mL of 30% _H2O2 solution respectively, and react The solution was reacted in an oil bath at 60°C and 800rpm/min. During the reaction, samples were taken at intervals, and then analyzed by concentration and gas chromatography. The results of catalyst recycling are shown in Figure 9.

It can be seen from Fig. 9 that after ten cycles of the catalyst, the conversion of DBT can still be maintained at 95.7%, which indicates that the catalyst prepared by the present invention has good recyclability.

Example 13

Preparation of catalyst (C ₁₈ -C ₂ -C ₁₈ ) ₂ ·Br·(PW ₁₂ O ₄₀ ):

As an illustrative example, the catalyst (C ₁₈ -C ₂ -C ₁₈ ) ₂ ·Br·(PW ₁₂ O ₄₀ ) can be prepared as follows: C ₁₈ -C ₂ -C ₁₈ is synthesized according to the route of Example 1; 0.096mmol of C ₁₈ -C ₂ -C ₁₈ was dissolved in 5mL of ethanol solution, and then 0.048mmol of H ₃ PW ₁₂ O ₄₀ was slowly added to obtain an off-white precipitate, then reacted for 12h, and finally filtered, washed, (C ₁₈ -C ₂ -C ₁₈ ) ₂ ·Br·(PW ₁₂ O ₄₀ ) was obtained by the drying method with a yield of about 70%.

Example 14

The purpose of this example is to study the influence of different polyacids on the catalytic efficiency.

Take 3.13 μmol of (C ₁₈ -C ₂ -C ₁₈ ) ₂ ·Br·(PW ₁₂ O ₄₀ ) into two-necked round-bottomed flasks, and then add 271 μmol of DBT and 50 mL of n-hexane as reactants to each bottle, 0.6mL of 30% H ₂ O ₂ solution, the reaction solution was reacted in an oil bath at 60°C and 800rpm/min. During the reaction, samples were taken at regular intervals, and then analyzed by concentration and gas chromatography. The time for complete conversion of DBT to DBTO ₂ (dibenzothiophene sulfone) was 19 minutes.

Example 15

Preparation of catalyst (C ₁₈ -C ₂ -C ₁₈ ) ₂ ·Br·(PMo ₁₂ O ₄₀ ):

As an illustrative example, the catalyst (C ₁₈ -C ₂ -C ₁₈ ) ₂ ·Br·(PMo ₁₂ O ₄₀ ) can be prepared as follows: C ₁₈ -C ₂ -C ₁₈ is synthesized according to the route of Example 1; will obtain 0.096mmol of C ₁₈ -C ₂ -C ₁₈ was dissolved in 5mL of ethanol solution, and then 0.048mmol of H ₃ PMo ₁₂ O ₄₀ was slowly added to obtain a yellow precipitate, then reacted for 12h, and finally filtered, washed, (C ₁₈ -C ₂ -C ₁₈ ) ₂ ·Br·(PMo ₁₂ O ₄₀ ) was obtained by the drying method with a yield of about 59%.

Example 16

The purpose of this example is to study the influence of different polyacids on the catalytic efficiency.

Add 3.13 μmol of (C ₁₈ -C ₂ -C ₁₈ ) ₂ ·Br·(PMo ₁₂ O ₄₀ ) to two-necked round-bottomed flasks respectively, then add 271 μmol of DBT and 50 mL of n-hexane as reactants to each bottle, 0.6mL of 30% H ₂ O ₂ solution, the reaction solution was reacted in an oil bath at 60°C and 800rpm/min. During the reaction, samples were taken at regular intervals, and then analyzed by concentration and gas chromatography. The time for complete conversion of DBT to DBTO ₂ (dibenzothiophene sulfone) was 29 minutes.

Claims (10)

1. a catalytic oxidation desulfurization catalyst, the expression formula that it is characterized in that described catalyst is (C _n-C _s-C _n) ₂y (XM ₁₂o ₄₀), C wherein _n-C _s-C _nfor double type surfactant, interval base s=2,4 or 6, alkyl chain n=14,16 or 18; Counter anion atom Y is halogen atom; Hetero atom X is phosphorus, silicon, boron, iron, cobalt, arsenic or germanium; Joining atom M is molybdenum or tungsten.

2. catalytic oxidation desulfurization catalyst according to claim 1, the expression formula that it is characterized in that described catalyst is (C ₁₈-C ₂-C ₁₈) ₂br (AsMo ₁₂o40), (C ₁₈-C ₄-C ₁₈) ₂br (AsMo ₁₂o40), (C ₁₈-C ₆-C ₁₈) ₂br (AsMo ₁₂o40), (C ₁₈-C ₂-C ₁₈) ₂br (AsW ₁₂o40), (C ₁₈-C ₂-C ₁₈) ₂br (PMo ₁₂o40) or (C ₁₈-C ₂-C ₁₈) ₂br (PW ₁₂o40).

3. catalytic oxidation desulfurization catalyst according to claim 1, is characterized in that described C _n-C _s-C _nfor C ₁₈-C ₂-C ₁₈, C ₁₈-C ₄-C ₁₈or C ₁₈-C ₆-C ₁₈.

4. catalytic oxidation desulfurization catalyst according to claim 1, is characterized in that described halogen is Br or Cl.

5. a preparation method for the catalytic oxidation desulfurization catalyst described in the arbitrary claim of claim 1-4, is characterized in that described method step is as follows:

1) synthetic C _n-C _s-C _ntype double type surfactant;

2) by 1.5-3mmol step 1) prepared C _n-C _s-C _ntype double type surfactant dissolves with the ethanol of 40-70mL, then slowly drips the H of 0.5-2mmol, 5-30mg/mL ₃xM ₁₂o ₄₀in ethanolic solution, stir 6-24h, then suction filtration, with ethanol and deionized water cyclic washing, finally obtains composite catalyst XM ₁₂c ₁₈c _n, drying for standby;

3) solvent, mould oil and oxidant are put into the round-bottomed flask reactor with reflux, then added reactant and composite catalyst XM ₁₂c ₁₈c _n, then under 40-80 ℃, 400-1000rpm rotating speed, stir, form emulsion, wherein the ratio of oxidant/reactant/catalyst is 20-25/1-3/0.01-0.015; The consumption judgement reaction end that utilizes thin-layered chromatography and gas chromatography monitoring sulfide, the reaction time, between 20-115 minute, stops stirring;

4) after reaction finishes, by standing, water oil content layer, then extract catalyst by the method for suction filtration, and the thick catalyst extracting is cleaned 3-5 time with ethanol, then in vacuum drying chamber, be dried, finally obtain the composite catalyst XM of recoverable ₁₂c ₁₈c _n.

6. the preparation method of catalytic oxidation desulfurization catalyst according to claim 5, is characterized in that described reactant is organosulfur compound.

7. the preparation method of catalytic oxidation desulfurization catalyst according to claim 6, is characterized in that described organosulfur compound is thiophene, benzothiophene, dibenzothiophenes and 4,6-dimethyl Dibenzothiophene, dimethyl sulfide or diethyl sulfide.

8. the preparation method of catalytic oxidation desulfurization catalyst according to claim 5, is characterized in that described solvent is deionized water.

9. the preparation method of catalytic oxidation desulfurization catalyst according to claim 5, is characterized in that described mould oil is the immiscible organic matter of nonpolar alkane or other and solvent and reactant.

10. the preparation method of catalytic oxidation desulfurization catalyst according to claim 9, is characterized in that described nonpolar alkane is hexadecane, the tetradecane, dodecane, normal octane or n-hexane.