CN107790173A - A kind of method for the catalyst and synthesizing dimethyl thioether for preparing dimethyl sulfide - Google Patents

Abstract

The invention relates to the field of catalytic materials, and discloses a catalyst for preparing dimethyl sulfide and a method for synthesizing dimethyl sulfide, wherein the catalyst contains molecular sieves; the characterization of the catalyst NH ₃ -TPD includes the following characteristics: at 150°C The amount of ammonia desorbed at -250°C is not more than 0.125mmol/g, the amount of ammonia desorbed at 450°C-550°C is not more than 0.036mmol/g, and the total amount of ammonia desorbed at 150°C-550°C is not less than 0.237mmol/g g. The catalyst provided by the invention can effectively catalyze the reaction of hydrogen sulfide and methanol, so that the method of the invention can achieve higher conversion rate of methanol while obtaining higher selectivity of dimethyl sulfide .

Description

Catalyst for preparing dimethyl sulfide and method for synthesizing dimethyl sulfide

technical field

The invention relates to a catalyst for preparing dimethyl sulfide and a method for synthesizing dimethyl sulfide. Specifically, it relates to an acidic catalyst containing molecular sieves for preparing dimethyl sulfide and a method for synthesizing dimethyl sulfide using the catalyst.

Background technique

A large amount of hydrogen sulfide is produced during oil processing and exploitation of low-quality natural gas fields. At present, with the heavy and inferior quality of crude oil and the exploitation of more inferior natural gas fields, the amount of hydrogen sulfide resources from oil processing and natural gas field exploitation is gradually increasing. In the face of a large amount of hydrogen sulfide resources, how to use it is an important issue.

The traditional way to utilize hydrogen sulfide is to selectively oxidize hydrogen sulfide to sulfur and water through the Claus process. However, the price of the product sulfur fluctuates greatly, and in the long run, it is difficult for the price of sulfur in my country to rise, and the added value of the product is low. In addition, with the strengthening of environmental regulations, the Claus process needs to add tail gas treatment devices to overcome the defects of tail gas pollution, making it difficult to effectively guarantee the social and economic benefits of the Claus process.

Dimethyl sulfoxide is an important chemical raw material, which is widely used in the fields of medicine, pesticide, electronic material, petrochemical industry and carbon fiber. Dimethyl sulfide is an intermediate raw material for the preparation of dimethyl sulfoxide. At present, there are two methods for preparing dimethyl sulfide, one is prepared by using hydrogen sulfide as raw material, and the other is prepared by using carbon disulfide as raw material. Although the latter is currently used by most enterprises in our country, the cost is relatively high. The former can effectively utilize hydrogen sulfide resources, the raw materials are easy to obtain, and the cost is low. It is a direction worthy of vigorous development to improve resource utilization.

CN1486786A discloses a catalyst for synthesizing dimethyl sulfide. The catalyst uses activated alumina as a carrier and an alkali metal oxide as an active component; the activated alumina carrier can be γ, δ, κ, ρ, η, etc. One or more mixtures of transition state alumina. The catalyst can be used for the reaction of hydrogen sulfide and methanol to generate dimethyl sulfide.

CN1217326A discloses a preparation method of dimethyl sulfide and methyl mercaptan, wherein, the sulfur compound containing 30-99mol% hydrogen sulfide and methanol are used as raw materials, and the ratio is the sulfur compound containing 30-99mol% hydrogen sulfide Sulfur in methanol: methanol = 1:0.6-2.5 (mol ratio), preheated to 300°C by gasification, then enters the reactor equipped with γ-Al ₂ O ₃ catalyst, the reaction temperature is 350-420°C, and the residence time is 1.5-5 seconds, the gas generated by the reaction is cooled by -18°C ice-salt water to obtain a condensed liquid. After standing for 10-20 minutes, the layers are separated, and the water in the lower layer is separated. The upper layer is dimethyl sulfide and methyl mercaptan. The miscibles are separated by rectification. The fraction cut off at 2.5-5.1°C is methyl mercaptan, and the fraction cut off at 37-39°C is dimethyl sulfide.

US4302605 discloses a continuous gas-phase process for preparing C ₁ -C ₁₂ dialkyl sulfides, which comprises reacting C ₁ -C ₁₂ alcohols with hydrogen sulfide at high temperature in the presence of a zeolite catalyst. The opening of the zeolite catalyst is 7-10 angstroms, the zeolite catalyst is X-type, Y-type or L-type, and based _on Na2O, the alkali metal content is less than 10% by weight; the reaction temperature is usually 250-450 ℃. The conversion of methanol obtained by this method is low.

Therefore, there is a need for a catalyst for preparing dimethyl sulfide and a method for synthesizing dimethyl sulfide with higher methanol conversion and dimethyl sulfide selectivity.

Contents of the invention

The purpose of the present invention is to provide a new catalyst for the preparation of dimethyl sulfide by the reaction of hydrogen sulfide and methanol and a method for synthesizing dimethyl sulfide, using the catalyst to obtain higher methanol conversion and dimethicone Selectivity of methyl sulfide.

In order to achieve the above object, the present invention provides a catalyst for the preparation of dimethyl sulfide, wherein the catalyst contains molecular sieves; the characterization of the catalyst NH ₃ -TPD includes the following characteristics: the amount of ammonia desorbed at 150°C-250°C Not more than 0.125mmol/g, the amount of ammonia desorbed at 450°C-550°C is not more than 0.036mmol/g, and the total amount of ammonia desorbed at 150°C-550°C is not less than 0.237mmol/g.

The present invention also provides a method for synthesizing dimethyl sulfide, the method comprising: reacting hydrogen sulfide and methanol in the presence of a catalyst to synthesize dimethyl sulfide; wherein, the catalyst is provided by the present invention catalyst.

By using the catalyst provided by the invention, in the preparation process of dimethyl sulfide, higher selectivity of dimethyl sulfide can be obtained, and a higher conversion rate of methanol can also be achieved. For example, the selectivity of dimethyl sulfide in Example 1 is 96.0%, while the conversion of methanol is 95.1%. While using the reference catalyst to prepare dimethyl sulfide in comparative example 1, the selectivity of dimethyl sulfide is only 55.6%, and the conversion rate of methanol is only 72.1%.

The catalyst provided by the present invention can have the above-mentioned better catalytic effect, and the reason may be that: on the one hand, the molecular sieve in the catalyst has a more stable skeleton structure; Catalyzed reaction with methanol to synthesize dimethyl sulfide to obtain higher selectivity of dimethyl sulfide and methanol conversion.

Other features and advantages of the present invention will be described in detail in the following detailed description.

Detailed ways

Specific embodiments of the present invention will be described in detail below. It should be understood that the specific embodiments described here are only used to illustrate and explain the present invention, and are not intended to limit the present invention.

Neither the endpoints nor any values of the ranges disclosed herein are limited to such precise ranges or values, and these ranges or values are understood to include values approaching these ranges or values. For numerical ranges, between the endpoints of each range, between the endpoints of each range and individual point values, and between individual point values can be combined with each other to obtain one or more new numerical ranges, these values Ranges should be considered as specifically disclosed herein.

According to the present invention, the catalyst for preparing dimethyl sulfide contains molecular sieves, and the NH ₃ -TPD characterization of the catalyst includes the following characteristics: the amount of ammonia desorbed at 150°C-250°C is not more than 0.125mmol/g, and at 450°C- The amount of ammonia desorbed at 550°C is not more than 0.036mmol/g, and the total amount of ammonia desorbed at 150°C-550°C is not less than 0.237mmol/g.

Preferably, the catalyst NH ₃ -TPD characterization includes the following characteristics: the amount of ammonia desorbed at 150°C-250°C is not more than 0.107mmol/g, and the amount of ammonia desorbed at 450°C-550°C is not more than 0.036mmol/g g, the total amount of ammonia desorbed at 150°C-550°C is not less than 0.237mmol/g.

According to the present invention, the catalyst contains molecular sieves, and the type of molecular sieves contained therein can be selected from molecular sieves with MFI structure, molecular sieves with BEA structure, molecular sieves with FAU structure, molecular sieves with MOR structure and molecular sieves with LTL structure. Various. Based on the total amount of the catalyst, the content of the molecular sieve may be 20-100% by weight.

According to the invention, the catalyst preferably contains a molecular sieve of MFI structure.

According to the present invention, the silicon-aluminum molar ratio of the molecular sieve with the MFI structure (in terms of oxides, that is, SiO ₂ /Al ₂ O ₃ , the same below) can be selected within a wide range. Preferably, in terms of oxides, the molecular sieve with the MFI structure has a molar ratio of silicon to aluminum of greater than 12 and less than or equal to 200; preferably, in terms of oxides, the molecular sieve with the MFI structure has a molar ratio of silicon to aluminum of 15- 150; more preferably, based on oxides, the molecular sieve with MFI structure has a molar ratio of silicon to aluminum of 20-70. When the molecular sieve with the MFI structure is in the above-mentioned preferred range of molar ratio of silicon to aluminum, the catalyst can obtain better catalytic activity.

According to the present invention, the content of sodium ions in the molecular sieve with MFI structure is different, which can affect the catalytic performance of the catalyst. Preferably, based on the total weight of the molecular sieve with the MFI structure, the content of Na ₂ O in the molecular sieve with the MFI structure is ≤0.1% by weight; preferably, the content of Na ₂ O in the molecular sieve with the MFI structure is ≤0.05% by weight %.

In the present invention, the specific surface area of the molecular sieve with the MFI structure is measured by nitrogen adsorption BET method, preferably, the specific surface area of the molecular sieve with the MFI structure is ≥280m ² /g, and the pore volume is ≥0.12mL/g; preferably, The specific surface area of the molecular sieve with the MFI structure is ≥320m ² /g, and the pore volume is ≥0.15mL/g.

According to the present invention, the molecular sieve with MFI structure is preferably HZSM-5 molecular sieve. The HZSM-5 molecular sieve can be obtained by various methods, such as commercially available, or obtained by various existing methods. Preferably, the HZSM-5 molecular sieve can firstly obtain a sodium type ZSM-5 molecular sieve by using a hydrothermal synthesis method, and then exchange the sodium ions in the sodium type ZSM-5 molecular sieve with ammonium ions through an exchange reaction to become an ammonium type ZSM-5 molecular sieve. 5 molecular sieve, and then roasted to obtain HZSM-5 molecular sieve.

In the present invention, the sodium ZSM-5 molecular sieve is converted into HZSM-5 molecular sieve through exchange reaction and roasting, and conventional technical means in the field can be adopted. For example, soluble ammonium salts such as NH ₄ Cl, ammonium sulfate and ammonium nitrate can be dissolved in deionized water, then stirred with sodium ZSM-5 molecular sieve at 60-90°C for 1-4 hours, then filtered and washed with water , after drying at 70-120°C, then roasting; wherein the roasting temperature is 450-650°C, and the roasting time is 1-6 hours, preferably the roasting temperature is 500-600°C, and the roasting time is 2-4 hours , to obtain HZSM-5 molecular sieve. The weight ratio of sodium ZSM-5 molecular sieve to ammonium salt is 1:0.2-1, and the weight ratio of sodium ZSM-5 molecular sieve to deionized water is 1:4-10.

According to the present invention, based on the total amount of the catalyst, the content of the molecular sieve with the MFI structure is 20-100% by weight. In the catalyst, the content of the molecular sieve with the MFI structure is within the above range, and the method provided by the invention can obtain higher methanol conversion and dimethyl sulfide selectivity. According to the present invention, the catalyst can also be a combination of molecular sieves with MFI structure and other molecular sieves, and the other molecular sieves can be selected from molecular sieves with BEA structure, molecular sieves with FAU structure, molecular sieves with MOR structure, and molecular sieves with LTL structure. One or more, as long as the acid amount and acid distribution of the catalyst are guaranteed to be within the scope of the present invention.

According to the invention, the catalyst may also contain a carrier and a binder. The range of selection of the carrier and binding agent is known to those skilled in the art, for example, the carrier can be selected from one or more of alumina, silica gel, kaolin, bentonite, diatomaceous earth, natural pumice and expanded perlite. Various. The binder may be selected from one or more of pseudo-boehmite, alumina sol and silica sol.

The present invention also provides a method for synthesizing dimethyl sulfide, the method comprising: reacting hydrogen sulfide with methanol in the presence of a catalyst to synthesize dimethyl sulfide; wherein the catalyst is provided by the present invention catalyst.

In the present invention, the reaction process in which the catalyst catalyzes the reaction of hydrogen sulfide and methanol is a gas-solid catalytic reaction process. Reactors suitable for gas-solid catalytic reaction processes in the art can be used, for example, fixed-bed reactors, such as tubular reactors, can be used. The catalyst is packed in the tubular reactor to form a catalyst bed. The tubular reactor is heated so that the temperature of the catalyst bed reaches the reaction temperature. Hydrogen sulfide and methanol are fed into the catalyst bed from one end of the tubular reactor to contact and react, and the reaction products are collected at the other end of the tubular reactor.

According to the present invention, hydrogen sulfide and methanol can be respectively added into the reactor and contacted on the catalyst to carry out a synthesis reaction to generate dimethyl sulfide. Preferably, the molar ratio of hydrogen sulfide to methanol is 1:1-4; preferably the molar ratio of hydrogen sulfide to methanol is 1:2-3. According to the chemical reaction formula, 1 mole of hydrogen sulfide consumes 2 moles of methanol for feeding, and the reaction synthesizes dimethyl sulfide, which can reduce the generation of by-products.

According to the present invention, in the reaction of synthesizing dimethyl sulfide from hydrogen sulfide and methanol, the total amount of the reactant hydrogen sulfide and methanol added to the reactor is measured by the total gas volume space velocity, wherein hydrogen sulfide is fed in gas form, and methanol is fed in liquid form. Form feed, but when calculating the amount passing through the catalyst bed, it is converted to the volume of gas at the reaction temperature. Preferably, the total gas volume space velocity of hydrogen sulfide and methanol is 200-2000h ^-1 . Preferably, the total gas volume space velocity of hydrogen sulfide and methanol is 500-1500h ^-1 . The gas volume space velocity refers to the total gas volume of hydrogen sulfide and methanol passing through a unit volume of catalyst per unit time (hour).

According to the present invention, preferably, the conditions of the catalytic reaction include: the reaction temperature is 250-500° C., and the reaction pressure is 1-10 atm in gauge pressure. The preferred reaction temperature is 270-330° C., and the reaction pressure is 1-5 atm in terms of gauge pressure. The temperature of the reaction is the temperature of the catalyst bed in the reactor, and the pressure of the reaction is the pressure in the reactor.

The present invention will be described in detail below by way of examples.

In the following examples, the component content of the reaction product is detected by gas chromatography (gas chromatograph is Agilent 7890 type, detects inorganic components by TCD detector, and detects organic components by FID detector); the specific surface area and pore volume of the catalyst adopt nitrogen adsorption BET method is measured (GB/T5816-1995); The silicon-aluminum molar ratio of molecular sieve adopts X-ray fluorescence method to measure (instrument is Japan Rigaku Electric Co., Ltd. 3013 type X-ray fluorescence spectrometer, tungsten target, excitation voltage 40kV, excitation current 50mA), The acid content and acid strength of the catalyst were measured by NH3-TPD method. The sample was purified in helium at 550°C for 1 hour, cooled to 150°C, adsorbed ammonia for 90 minutes, purged with helium and then heated to 250, 350, Measure the released ammonia gas at 450 and 550 degrees.

The conversion of methanol and the selectivity of dimethyl sulfide are calculated by the following definitions:

Example 1

This example is used to illustrate the catalyst for preparing dimethyl sulfide of the present invention and its catalytic performance.

Taking HZSM-5 as the active phase, kaolin as the carrier, and pseudoboehmite as the binding agent to prepare the catalyst, the silicon-aluminum ratio of HZSM-5 is 26.8, and the sodium oxide content is 0.02% by weight. The total amount of the catalyst is As a benchmark, the molecular sieve weight content is 70%. Add 100g of HZSM-5 molecular sieve into deionized water, ultrasonically disperse for 60 minutes, then add 30g of pseudo-boehmite and 12.8g of kaolin to the slurry, and continue ultrasonically dispersing for 30min. The mixed slurry was suction filtered, and the obtained filter cake was dried in a vacuum oven at a temperature of 50°C. Put the dried filter cake into extruder, knead with nitric acid aqueous solution to form a ball, and extrude to form. The catalyst is cylindrical with a diameter of 2 mm. The molded catalyst was placed in a reaction tube, and treated with a 50% ethanol aqueous solution at 200°C for 5 hours, and the liquid weight hourly space velocity was 0.05h ^-1 . The acid amount and acid distribution data of the catalyst are shown in Table 1. The catalyst is smashed and sieved, and 20-40 mesh particles are taken and packed in a tubular reaction tube with a diameter of 0.8 cm and a length of 55 cm. The volume of the bed of catalyst particles is 2.0 cm ³ .

Under the condition that the reaction temperature is 310°C, the reaction pressure is 1 atm, the feed molar ratio of hydrogen sulfide and methanol is 1:2, and the total gas volume space velocity is 700h ^-1 , the catalysis for the preparation of dimethyl sulfide is carried out reaction. The product obtained after the catalytic reaction was analyzed by gas chromatography for 3 hours, and the conversion rate of methanol and the selectivity of dimethyl sulfide were calculated according to the analysis results. The calculation results are shown in Table 2.

Example 2

This example is used to illustrate the catalyst for preparing dimethyl sulfide of the present invention and its catalytic performance.

Taking HZSM-5 as the active phase, alumina as the carrier, and pseudo-boehmite as the binder to prepare the catalyst, the silicon-aluminum ratio of HZSM-5 is 47.5, and the sodium oxide content is 0.03% by weight, based on the total amount of the catalyst As a benchmark, the molecular sieve weight content is 80%. Add 100g of HZSM-5 molecular sieve into deionized water, ultrasonically disperse for 50min, then add 20g of pseudo-boehmite and 5g of alumina to the slurry, and continue ultrasonically dispersing for 40min. The mixed slurry was suction filtered, and the obtained filter cake was dried in a vacuum oven at a temperature of 40°C. Put the dried filter cake into extruder, knead with nitric acid aqueous solution to form a ball, and extrude to form. The catalyst is cylindrical with a diameter of 2 mm. The molded catalyst was placed in a reaction tube, and treated with 40% ethanol aqueous solution at 200°C for 6 hours, and the liquid weight hourly space velocity was 0.05h ^-1 . The acid amount and acid distribution data of the catalyst are shown in Table 1. The catalyst is smashed and sieved, and 20-40 mesh particles are taken and packed in a tubular reaction tube with a diameter of 0.8 cm and a length of 55 cm. The volume of the bed of catalyst particles is 2.0 cm ³ .

Under the condition that the reaction temperature is 330°C, the reaction pressure is 1 atm, the feed molar ratio of hydrogen sulfide and methanol is 1:2, and the total gas volume space velocity is 750h ^-1 , the catalysis for the preparation of dimethyl sulfide is carried out reaction. The product obtained after the catalytic reaction was analyzed by gas chromatography for 3 hours, and the conversion rate of methanol and the selectivity of dimethyl sulfide were calculated according to the analysis results. The calculation results are shown in Table 2.

Example 3

This example is used to illustrate the catalyst for preparing dimethyl sulfide of the present invention and its catalytic performance.

With HZSM-5 as the active phase, pseudo-boehmite and alumina sol are used as the binding agent to prepare the catalyst. The silicon-aluminum ratio of HZSM-5 is 53.2, and the sodium oxide content is 0.05% by weight. Based on the total amount of the catalyst, Molecular sieve weight content is 90%. Add 100g of HZSM-5 molecular sieve into deionized water, ultrasonically disperse for 50 minutes, then add 10g of pseudo-boehmite to the slurry, and continue ultrasonically dispersing for 40 minutes. The mixed slurry was suction filtered, and the obtained filter cake was dried in a vacuum oven at a temperature of 50°C. Put the dried filter cake into extruder, add 5.5g of aluminum sol, knead with nitric acid aqueous solution to form a ball, and extrude to shape. The catalyst is cylindrical with a diameter of 2mm. The molded catalyst was placed in a reaction tube, and treated with 40% ethanol aqueous solution at 200°C for 8 hours, and the liquid weight hourly space velocity was 0.03h ^-1 . The acid amount and acid distribution data of the catalyst are shown in Table 1. The catalyst is smashed and sieved, and 20-40 mesh particles are taken and packed in a tubular reaction tube with a diameter of 0.8 cm and a length of 55 cm. The volume of the bed of catalyst particles is 2.0 cm ³ .

Under the condition that the reaction temperature is 300°C, the reaction pressure is 1 atm, the feed molar ratio of hydrogen sulfide and methanol is 1:2, and the total gas volume space velocity is 720h ^-1 , the catalysis for the preparation of dimethyl sulfide is carried out reaction. The product obtained after the catalytic reaction was analyzed by gas chromatography for 3 hours, and the conversion rate of methanol and the selectivity of dimethyl sulfide were calculated according to the analysis results. The calculation results are shown in Table 2.

Example 4

This example is used to illustrate the catalyst for preparing dimethyl sulfide of the present invention and its catalytic performance.

With HZSM-5 as the active phase, kaolin as the carrier pseudo-boehmite and alumina sol as the binder to prepare the catalyst, the silicon-aluminum ratio of HZSM-5 is 39.7, and the sodium oxide content is 0.03% by weight, based on the total amount of the catalyst As a benchmark, the molecular sieve weight content is 70%. Add 100g of HZSM-5 molecular sieve into deionized water, ultrasonically disperse for 45min, then add 30g of pseudo-boehmite and 10g of kaolin to the slurry, and continue ultrasonically dispersing for 45min. The mixed slurry was suction filtered, and the obtained filter cake was dried in a vacuum oven at a temperature of 50°C. Put the dried filter cake into extruder, add 14g of aluminum sol, knead with nitric acid aqueous solution to form a ball, and extrude to form. The catalyst is cylindrical with a diameter of 2mm. The molded catalyst was placed in a reaction tube, and treated with 40% ethanol aqueous solution at 180°C for 7 hours, and the liquid weight hourly space velocity was 0.05h ^-1 . The acid amount and acid distribution data of the catalyst are shown in Table 1. The catalyst is smashed and sieved, and 20-40 mesh particles are taken and packed in a tubular reaction tube with a diameter of 0.8 cm and a length of 55 cm. The volume of the bed of catalyst particles is 2.0 cm ³ .

Under the condition that the reaction temperature is 310°C, the reaction pressure is 1 atm, the feed molar ratio of hydrogen sulfide and methanol is 1:2, and the total gas volume space velocity is 750h ^-1 , the catalysis for the preparation of dimethyl sulfide is carried out reaction. The product obtained after the catalytic reaction was analyzed by gas chromatography for 3 hours, and the conversion rate of methanol and the selectivity of dimethyl sulfide were calculated according to the analysis results. The calculation results are shown in Table 2.

Example 5

This example is used to illustrate the catalyst for preparing dimethyl sulfide of the present invention and its catalytic performance.

Taking HZSM-5 as the active phase, silicon oxide as the carrier, and pseudoboehmite as the binder to prepare the catalyst, the silicon-aluminum ratio of HZSM-5 is 45.1, and the sodium oxide content is 0.06% by weight. The total amount of the catalyst is As a benchmark, the molecular sieve weight content is 70%. Add 100g of HZSM-5 molecular sieve into deionized water, ultrasonically disperse for 60min, then add 35g of pseudo-boehmite and 7.8g of silicon oxide to the slurry, and continue ultrasonically dispersing for 40min. The mixed slurry was suction filtered, and the obtained filter cake was dried in a vacuum oven at a temperature of 45°C. Put the dried filter cake into extruder, knead with nitric acid aqueous solution to form a ball, and extrude to form. The catalyst is cylindrical with a diameter of 2 mm. The molded catalyst was placed in a reaction tube, and treated with 50% ethanol aqueous solution at 170°C for 6 hours, and the liquid weight hourly space velocity was 0.04h ^-1 . The acid amount and acid distribution data of the catalyst are shown in Table 1. The catalyst is smashed and sieved, and 20-40 mesh particles are taken and packed in a tubular reaction tube with a diameter of 0.8 cm and a length of 55 cm. The volume of the bed of catalyst particles is 2.0 cm ³ .

Under the condition that the reaction temperature is 300°C, the reaction pressure is 1 atm, the feed molar ratio of hydrogen sulfide and methanol is 1:2, and the total gas volume space velocity is 700h ^-1 , the catalysis for the preparation of dimethyl sulfide is carried out reaction. The product obtained after the catalytic reaction was analyzed by gas chromatography for 3 hours, and the conversion rate of methanol and the selectivity of dimethyl sulfide were calculated according to the analysis results. The calculation results are shown in Table 2.

Example 6

This example is used to illustrate the catalyst for preparing dimethyl sulfide of the present invention and its catalytic performance.

The catalyst of dimethyl sulfide was prepared according to the method of Example 1, except that the silicon-aluminum ratio of HZSM-5 was 37.8. The formed catalyst was placed in a reaction tube, and treated with 50% ethanol aqueous solution at 220° C. for 6 hours. The acid amount and acid distribution data of the catalyst are shown in Table 1.

Using the above catalyst, the catalytic reaction for preparing dimethyl sulfide was carried out according to the conditions of Example 1. The product obtained after the catalytic reaction was analyzed by gas chromatography for 3 hours, and the conversion rate of methanol and the selectivity of dimethyl sulfide were calculated according to the analysis results. The calculation results are shown in Table 2.

Comparative example 1

With HZSM-5 as the active phase, alumina as the carrier, pseudo-boehmite and alumina sol as the binder to prepare the catalyst, the silicon-aluminum ratio of HZSM-5 is 50.4, and the sodium oxide content is 0.03% by weight. The total amount is the basis, and the molecular sieve weight content is 70%. Put 100g of HZSM-5 molecular sieve, 7g of alumina and 33g of pseudo-boehmite into the extruder and mix evenly, add 14.3g of aluminum sol, knead with nitric acid aqueous solution to form a ball, and extrude into a rod. The catalyst is cylindrical, with a diameter of 2mm. The acid amount and acid distribution data of the catalyst are shown in Table 1. The catalyst is smashed and sieved, and 20-40 mesh particles are taken and packed in a tubular reaction tube with a diameter of 0.8 cm and a length of 55 cm. The volume of the bed of catalyst particles is 2.0 cm ³ .

Under the condition that the reaction temperature is 290°C, the reaction pressure is 1 atm, the feed molar ratio of hydrogen sulfide and methanol is 1:2, and the total gas volume space velocity is 700h ^-1 , the catalysis for the preparation of dimethyl sulfide is carried out reaction. The product obtained after the catalytic reaction was analyzed by gas chromatography for 3 hours, and the conversion rate of methanol and the selectivity of dimethyl sulfide were calculated according to the analysis results. The calculation results are shown in Table 2.

Comparative example 2

Taking HZSM-5 as the active phase, silicon oxide as the carrier, and pseudoboehmite as the binder to prepare the catalyst, the silicon-aluminum ratio of HZSM-5 is 28.3, and the sodium oxide content is 0.02% by weight, based on the total amount of the catalyst As a benchmark, the molecular sieve weight content is 70%. Put 100g of HZSM-5 molecular sieve, 12.8g of silicon oxide and 30g of pseudoboehmite into the extruder and mix evenly, knead with nitric acid aqueous solution to form a ball, and extrude into a rod. The catalyst is cylindrical, with a diameter of 2mm. The acid amount and acid distribution data of the catalyst are shown in Table 1. The catalyst is smashed and sieved, and 20-40 mesh particles are taken and packed in a tubular reaction tube with a diameter of 0.8 cm and a length of 55 cm. The volume of the bed of catalyst particles is 2.0 cm ³ .

Under the condition that the reaction temperature is 330°C, the reaction pressure is 1 atm, the feed molar ratio of hydrogen sulfide and methanol is 1:2, and the total gas volume space velocity is 750h ^-1 , the catalysis for the preparation of dimethyl sulfide is carried out reaction. The product obtained after the catalytic reaction was analyzed by gas chromatography for 3 hours, and the conversion rate of methanol and the selectivity of dimethyl sulfide were calculated according to the analysis results. The calculation results are shown in Table 2.

Table 1

Table 2

Example number Methanol conversion (%) Dimethyl sulfide selectivity (%) Example 1 95.1 96.0 Example 2 96.2 95.0 Example 3 94.9 95.6 Example 4 95.5 95.1 Example 5 94.6 95.8 Example 6 94.9 94.5 Comparative example 1 72.1 55.6 Comparative example 2 89.6 70.0

As can be seen from the data in Table 2, the preparation of dimethyl sulfide catalyst provided by the present invention can effectively catalyze the synthetic reaction of hydrogen sulfide and methanol to carry out within the acid distribution range limited by the present invention, and the reaction result obtains higher At the same time, the selectivity of dimethyl sulfide can also make the conversion rate of methanol higher.

The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention. These simple modifications All belong to the protection scope of the present invention.

In addition, it should be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable way if there is no contradiction. The combination method will not be described separately.

In addition, various combinations of different embodiments of the present invention can also be combined arbitrarily, as long as they do not violate the idea of the present invention, they should also be regarded as the disclosed content of the present invention.

Claims (10)

1. A catalyst for preparing dimethyl sulfide, characterized in that the catalyst contains molecular sieves; the characterization of the catalyst NH ₃ -TPD includes the following features: the amount of ammonia desorbed at 150°C-250°C is not more than 0.125mmol /g, the amount of ammonia desorbed at 450°C-550°C is not more than 0.036mmol/g, and the amount of total ammonia desorbed at 150°C-550°C is not less than 0.237mmol/g. 2. The catalyst according to claim 1, wherein the NH ₃ -TPD characterization of the catalyst includes the following characteristics: the amount of ammonia desorbed at 150°C-250°C is not more than 0.107mmol/g, and the amount of ammonia desorbed at 450°C-550°C The amount of attached ammonia is not more than 0.036mmol/g, and the total amount of ammonia desorbed at 150°C-550°C is not less than 0.237mmol/g. 3. The catalyst according to claim 1 or 2, wherein the molecular sieve contained in the catalyst is selected from one of the molecular sieves of the MFI structure, the molecular sieve of the BEA structure, the molecular sieve of the FAU structure, the molecular sieve of the MOR structure and the molecular sieve of the LTL structure one or more species. 4. The catalyst according to claim 1 or 2, wherein the catalyst contains a molecular sieve of MFI structure. 5. The catalyst according to claim 4, wherein, in terms of oxides, the molar ratio of silicon to aluminum of the molecular sieve with MFI structure is 20-70. 6 . The catalyst according to claim 4 , wherein, based on the total weight of the molecular sieve with MFI structure, the content of Na ₂ O in the molecular sieve with MFI structure is ≤0.1% by weight. 7. The catalyst according to claim 4, wherein, based on the total amount of the catalyst, the content of the molecular sieve with the MFI structure is 20-100% by weight. 8. The catalyst of claim 1, wherein the catalyst further comprises a carrier and a binder. 9. The catalyst according to claim 8, wherein the carrier is selected from one or more of alumina, silica gel, kaolin, bentonite, diatomaceous earth, natural pumice and expanded perlite; One or more selected from pseudo-boehmite, alumina sol and silica sol. 10. A method for synthesizing dimethyl sulfide, the method comprising: in the presence of a catalyst, hydrogen sulfide and methanol are reacted to synthesize dimethyl sulfide; it is characterized in that, the catalyst is claim 1- The catalyst described in any one of 9.