Catalyst for synthesizing dimethyl sulfide from hydrogen sulfide and methanol and preparation method of catalyst

Abstract

The invention provides a catalyst for synthesizing dimethyl sulfide from hydrogen sulfide and methanol. The catalyst comprises a carrier and an active component in a mass ratio of 1: (0.1-1), the carrier comprises pseudo-boehmite, a sulfamic acid compound and titanium pyrophosphate, and the mass ratio of the pseudo-boehmite to the sulfamic acid compound to the titanium pyrophosphate is (90-99): (0.5-5): (0.5-5); the active components comprise a soluble tungsten-containing compound, a potassium alkoxide compound and ammonia water, and the mass ratio of the soluble tungsten-containing compound to the potassium alkoxide compound to the ammonia water is 1: (0.1-1): (1-2). The sulfamic acid compound is adopted in the catalyst for synthesizing the dimethyl sulfide from the hydrogen sulfide and the methanol, the Lewis acidity of the aluminum oxide carrier can be improved through a sulfonic acid group in the sulfamic acid compound, the yield of the dimethyl sulfide is increased, the yield of the methyl mercaptan is inhibited, and the selectivity of the dimethyl sulfide is improved.

Description

Technical Field

[0001] The invention belongs to the field of chemical catalysts, and in particular relates to a catalyst for synthesizing methyl sulfide from hydrogen sulfide and methanol and a preparation method thereof. Background Art

[0002] Methyl sulfide is an important organic intermediate and an intermediate for the production of dimethyl sulfoxide, methionine and pesticides. It can be used as a solvent for organic synthesis, polymerization reaction and cyanidation reaction. It is used for analytical tests, spinning of polyacrylonitrile and other synthetic fibers and hydraulic oil. It can also be used as an odorizer for city gas, an industrial purifier, a paint release agent, a battery low-temperature preservative, a pesticide penetrant, etc. It is used topically in blood medicines, plant pathology and nutrients. It has been industrialized in the 1950s-1970s. There are mainly the following production routes: 1. Methanol and carbon disulfide synthesis method, methanol and carbon disulfide are mixed evenly according to the theoretical ratio, metered, heated, and sent to the reactor for reaction. The reaction gas is condensed and refined to obtain the finished product. 2. Methanol and hydrogen sulfide synthesis method, methanol and hydrogen sulfide are mixed in a certain proportion, preheated and then enter the catalytic reactor for reaction, the reactants are separated and dehydrated, and then distilled to obtain the finished product. 3. Dimethyl ether and hydrogen sulfide synthesis method: dimethyl ether and hydrogen sulfide are mixed in a certain proportion, and after preheating, they enter the catalytic reactor for reaction. The reactants are separated and dehydrated, and then distilled to obtain the finished product. The raw materials of the methanol-hydrogen sulfide method are low in price and can be combined with industrial waste gas to turn waste into treasure, which helps environmental protection and is suitable for large-scale production.

[0003] Patent CN109134324A has developed a catalyst for preparing methyl sulfide by reacting dimethyl ether with hydrogen sulfide. The article mentions the use of BEA-structured molecular sieves as catalysts, and only discusses the silicon-aluminum ratio. The examples do not provide detailed catalytic effects. The catalyst is used at a temperature of 390-400°C. At this temperature, the purity and volume of hydrogen sulfide waste gas from the industrial park are unstable, which affects the mercaptan ratio and leads to an increase in the by-product dimethyl ether. Therefore, the selectivity of methyl sulfide in this method is unstable, which is why this method cannot provide catalyst conversion and selectivity data.

[0004] US4302605 discloses a continuous gas phase method for preparing C1-C12 dialkyl sulfide, which comprises reacting C1-C12 alcohol and hydrogen sulfide under high temperature conditions in the presence of a zeolite catalyst. The zeolite catalyst has an opening of 7-10 angstroms, is of X-type, Y-type or L-type, and has an alkali metal content of less than 10% by weight, calculated as Na2O, and the reaction temperature is generally 250-450°C. The method has a low methanol conversion rate. Summary of the invention

[0005] In view of this, the present invention aims to overcome the defects in the prior art and proposes a catalyst for synthesizing methyl sulfide from hydrogen sulfide and methanol and a preparation method thereof. The catalyst has a high methanol conversion rate and methyl sulfide selectivity, is not prone to carbon deposition, and the life of the catalyst is greatly improved.

[0006] To achieve the above object, the technical solution of the present invention is achieved as follows: The present invention provides a catalyst for synthesizing methyl sulfide from hydrogen sulfide and methanol, wherein the catalyst comprises a carrier and an active component in a mass ratio of 1:0.1-1; The carrier comprises pseudo-boehmite, aminosulfonic acid compound and titanium pyrophosphate, and the mass ratio of the pseudo-boehmite, aminosulfonic acid compound and titanium pyrophosphate is 90-99:0.5-5:0.5-5; The active components include soluble tungsten-containing compounds, potassium alcohol compounds and ammonia water, and the mass ratio of the soluble tungsten-containing compounds, potassium alcohol compounds and ammonia water is 1:0.1-1:1-2.

[0007] Furthermore, the aminosulfonic acid compound is at least one of aminosulfonic acid, 2-aminoethanesulfonic acid or 3-aminopropanesulfonic acid; and the concentration of the ammonia water is 20-30%.

[0008] Furthermore, the soluble tungsten-containing compound is at least one of silicotungstic acid, sodium tungstate, lithium tungstate, potassium tungstate, ammonium metatungstate, ammonium paratungstate, cesium tungstate, tungsten nitride or sodium phosphotungstate; the potassium alcoholate compound is at least one of potassium methoxide, potassium ethoxide or potassium tert-butoxide.

[0009] The present invention also proposes a method for preparing a catalyst for synthesizing methyl sulfide from hydrogen sulfide and methanol, comprising the following steps: Step 1 is to mix pseudo-boehmite, aminosulfonic acid compound, titanium pyrophosphate and a first portion of deionized water to obtain a first material, granulate the first material to obtain first particles, and dry and calcine the first particles to obtain a carrier; Step 2 is to disperse the soluble tungsten-containing compound, the potassium alcoholate compound and the ammonia water in the second portion of deionized water to obtain an impregnation solution; Step 3 is to immerse the carrier obtained in step 1 into the impregnation solution obtained in step 2 to obtain a carrier, and dry the carrier to constant weight to obtain the catalyst for synthesizing methyl sulfide from hydrogen sulfide and methanol.

[0010] Furthermore, the temperature of the drying step in step 1 is 80-120°C; the temperature of the calcining step in step 1 is 300-500°C.

[0011] Furthermore, the mass of the first part of deionized water in step 1 is 50% of the mass of the pseudo-boehmite.

[0012] Furthermore, the mixing step in step 1 is performed by using a kneader; and the granulation step in step 1 is performed by using an extruder or a ball rolling machine.

[0013] Furthermore, the temperature of the dispersion step in step 2 is 40-90°C.

[0014] Furthermore, the time of the impregnation step in step 3 is 0.5-24h.

[0015] Furthermore, the temperature of the drying step in step 3 is 80-120°C.

[0016] The raw material used in step 2 contains crystalline water or does not contain crystalline water; if the raw material used in step 2 contains crystalline water, the amount of the solvent (the second part of deionized water) is the difference between the maximum absorption mass of the solvent by the carrier described in step 1 and the total mass of crystalline water.

[0017] Compared with the prior art, the present invention has the following advantages: The catalyst for synthesizing methyl sulfide from hydrogen sulfide and methanol of the present invention adopts aminosulfonic acid compounds. The sulfonic acid group in the aminosulfonic acid compounds can improve the Lewis acidity of the alumina carrier, help to improve the yield of methyl sulfide, inhibit the yield of methyl mercaptan, and improve the selectivity of methyl sulfide.

[0018] In the carrier of the catalyst for synthesizing methyl sulfide from hydrogen sulfide and methanol described in the present invention, the amino group of the aminosulfonic acid compound and the oxygen vacancy lattice unique to titanium pyrophosphate coordinate with each other, thereby improving the adsorption strength of the reaction raw materials hydrogen sulfide and methanol on the catalyst surface, and the potassium alcohol compound can effectively inhibit the generation of by-products CO, CO2, and dimethyl ether to achieve the purpose of improving the selectivity of methyl sulfide, which further improves the methanol conversion rate and the yield of methyl sulfide.

[0019] The titanium pyrophosphate in the carrier of the catalyst for synthesizing methyl sulfide from hydrogen sulfide and methanol of the present invention has a three-dimensional structure composed of corner-sharing TiO6 octahedrons and PO4 tetrahedrons, which can be K + Storage provides a large space, making K + It is not easy to lose, which enhances the catalyst's ability to resist carbon deposition, and is very easy to combine with W ions to form Ti-W bonds, thereby increasing the reaction activation energy of the active component W, the conversion rate of methanol, and the yield of dimethyl sulfide. DETAILED DESCRIPTION

[0020] Unless otherwise defined, the technical terms used in the following examples have the same meanings as those generally understood by those skilled in the art to which the present invention belongs. The test reagents used in the following examples, unless otherwise specified, are all conventional biochemical reagents; the experimental methods, unless otherwise specified, are all conventional methods.

[0021] The present invention will be described in detail below with reference to the embodiments.

[0022] Example 1 A method for preparing a catalyst for synthesizing methyl sulfide from hydrogen sulfide and methanol comprises the following steps: Step 1, 99 g of pseudo-boehmite, 0.5 g of aminosulfonic acid, 0.5 g of titanium pyrophosphate and 49.5 g of the first portion of deionized water are mixed uniformly to obtain a first material, the first material is granulated to obtain first particles, the first particles are dried at 80° C., and then calcined at 300° C. to obtain a carrier; Step 2, 5g of ammonium metatungstate, 0.5g of potassium methoxide, and 5g of 20% ammonia water at 40°C are dispersed in 51g of the second portion of deionized water (the water absorption rate of the carrier is measured to be 55%, and the 20% ammonia water used contains 4g of water) to obtain an impregnation solution; Step 3, impregnating the carrier obtained in step 1 into the impregnation solution obtained in step 2 for 0.5 h to obtain an impregnated carrier; drying the impregnated carrier at 80° C. to constant weight to obtain the catalyst for synthesizing methyl sulfide from hydrogen sulfide and methanol.

[0023] Comparative Example 1 The only difference from Example 1 is that in step 1, sulfamic acid is not added.

[0024] Comparative Example 2 The only difference from Example 1 is that titanium pyrophosphate is not added in step 1.

[0025] Comparative Example 3 The only difference from Example 1 is that potassium methoxide is not added in step 2.

[0026] Example 2 A method for preparing a catalyst for synthesizing methyl sulfide from hydrogen sulfide and methanol comprises the following steps: Step 1, 95 g of pseudo-boehmite, 2.5 g of 2-aminoethanesulfonic acid, 2.5 g of titanium pyrophosphate and 47.5 g of the first portion of deionized water are mixed uniformly to obtain a first material, the first material is granulated to obtain first particles, the first particles are dried at 100° C., and then calcined at 400° C. to obtain a carrier; Step 2, 10g of ammonium tungstate, 5g of potassium ethoxide, and 15g of 25% ammonia water at 70°C are dispersed in 46.75g of the second part of deionized water (the water absorption rate of the carrier is measured to be 58%, and the 25% ammonia water used contains 11.25g of water) to obtain an impregnation solution; Step 3, impregnating the carrier obtained in step 1 into the impregnation solution obtained in step 2 for 12 hours to obtain an impregnated carrier; drying the impregnated carrier at 100° C. to constant weight to obtain the catalyst for synthesizing methyl sulfide from hydrogen sulfide and methanol.

[0027] Example 3 A method for preparing a catalyst for synthesizing methyl sulfide from hydrogen sulfide and methanol comprises the following steps: Step 1, 90 g of pseudo-boehmite, 5 g of 3-aminopropane sulfonic acid, 5 g of titanium pyrophosphate and 45 g of the first portion of deionized water are mixed uniformly to obtain a first material, the first material is granulated to obtain first particles, the first particles are dried at 120° C., and then calcined at 500° C. to obtain a carrier; Step 2, dispersing 20g of ammonium tungstate, 20g of potassium tert-butoxide, and 40g of 30% ammonia water at 90°C in 32g of the second part of deionized water (the water absorption rate of the carrier is measured to be 60%, and the 30% ammonia water used contains 28g of water) to obtain an impregnation solution; Step 3, impregnating the carrier obtained in step 1 into the impregnation solution obtained in step 2 for 24 hours to obtain an impregnated carrier; drying the impregnated carrier at 120° C. to constant weight to obtain the catalyst for synthesizing methyl sulfide from hydrogen sulfide and methanol.

[0028] Experimental Example 1 This experimental example is to evaluate the performance of the methyl sulfide catalyst prepared in Examples 1-3 and the catalyst prepared in Comparative Examples 1-3.

[0029] The synthesis reaction of this experimental example adopts a fixed-bed reactor at normal pressure and adopts the existing process flow of synthesizing methyl sulfide by vaporizing hydrogen sulfide and methanol, specifically: (1) 10 ml of catalyst was loaded onto the catalyst tray of the reaction tube. After the reaction tube was airtight, 50 ml / min of nitrogen was purged into the reaction tube. The temperature of the reaction furnace was then raised to 400 °C and switched to 50 ml / min of 99% hydrogen sulfide for 2 h.

[0030] (2) After the sulfidation is completed, the furnace temperature is lowered to 330°C, the hydrogen sulfide flow rate is increased to 67.00 ml / min, and methanol is fed at 0.25 ml / min. After the methanol is vaporized in the vaporization chamber, the molar ratio of methanol to hydrogen sulfide is 2:1, and the air velocity is 1200 GHSV / h. -1 .

[0031] (3) The reaction pipeline is electrically heated at no less than 200°C to prevent the product from liquefying, and the tail gas is fed into gas chromatography for analysis.

[0032] (4) Dimethyl sulfide selectivity (based on carbon balance) S DMS = 2W DMS / (W MT +2W DMS +W CH4 +2W DME +W CO +W CO2 )*100% Methanol conversion rate X ME =(W MT +2W DMS +W CH4 +2W DME +W CO +W CO2 ) / (W MT +2W DMS +W CH4 +2W DME +W CO +W CO2 +W ME )*100% Methyl sulfide yield Y DMS =S DMS *X ME W- product content ME, MT, DMS, DME, CH4, CO, CO2 represent methanol, methyl mercaptan, methyl sulfide, dimethyl ether, methane, carbon monoxide, and carbon dioxide respectively.

[0033] (5) The evaluation time of each experimental case is 500 h.

[0034] The performance evaluation results are shown in Table 1-4.

[0035] Table 1 Initial activity of catalyst project CO % CH4 % CO2 % H2S % CH3OH % CH3OCH3 % CH3SH % CH3SHC3 % XME SMT YMT Example 1 0.06 0.05 0.03 30.61 14.3 0.00 6.56 48.39 87.86% 93.53% 82.17% Comparative Example 1 0.05 0.03 0.02 35.37 31.37 0.00 9.19 23.97 64.59% 83.77% 54.11% Comparative Example 2 0.06 0.02 0.02 28.46 40.14 0.00 4.39 26.91 59.24% 92.37% 54.73% Comparative Example 3 8.99 1.05 0.59 19.74 24.43 1.38 5.1 38.72 79.70% 80.73% 64.34% Example 2 0.04 0.02 0.03 13.09 14.42 0.00 6.84 65.56 90.55% 95.02% 86.03% Example 3 0.03 0.01 0.00 12.69 9.08 0.00 4.65 73.54 94.35% 96.91% 91.44% Table 2 Catalyst activity after 500 hours project CO % CH4 % CO2 % H2S % CH3OH % CH3OCH3 % CH3SH % CH3SHC3 % XME SMT YMT Example 1 0.15 0.12 0.09 35.27 16.25 0.00 6.03 42.09 84.79% 92.94% 78.81% Comparative Example 1 0.1 0.15 0.13 38.14 33.56 0.00 9.55 18.37 58.17% 78.72% 45.79% Comparative Example 2 0.14 0.08 0.05 30.57 42.28 0.00 4.68 22.2 53.86% 89.97% 48.46% Comparative Example 3 9.29 1.55 1.35 23.68 30.43 2.55 5.83 25.32 70.79% 68.66% 48.60% Example 2 0.05 0.02 0.02 13.35 14.98 0.00 6.94 64.64 90.10% 94.84% 85.45% Example 3 0.03 0.01 0.01 12.83 9.45 0.00 4.85 72.82 94.09% 96.75% 91.03% Table 3 XRF analysis results Table 4 ICP analysis results According to the results in Table 1, when the catalysts No. 1-3 prepared in Examples 1-3 were used to synthesize methyl sulfide from hydrogen sulfide and methanol, the catalyst in Example 3 had the best performance, with the highest methanol conversion rate, methyl sulfide selectivity, and methyl sulfide yield, and the data before and after 500 hours were 94.35%, 94.09%, 96.91%, 96.75%, 91.44%, and 91.03%, respectively.

[0036] Table 3 is the XRF analysis results of Example 1 and Comparative Example 1. It is obvious that since no aminosulfonic acid is added to Comparative Example 1, the content of SO3 is not detected in the analysis results. The methanol conversion rate of Comparative Example 1 is 64.59%, and the methanol conversion rate of Example 1 is 87.86%. The methanol conversion rate of Comparative Example 1 is 23.27% lower than that of Example 1. The selectivity and yield of methyl sulfide in Comparative Example 1 are 14.22% and 33.02% lower than those in Example 1, respectively. The yield of methyl mercaptan in Comparative Example 1 is 3.52% higher than that in Example 1, which shows that aminosulfonic acid compounds help to improve the methanol conversion rate, the yield of methyl sulfide, inhibit the yield of methyl mercaptan, and improve the selectivity of methyl sulfide.

[0037] From the results in Table 1, it can be seen that the methanol conversion rate, methyl sulfide selectivity and methyl sulfide yield of Comparative Example 1 are 28.62%, 1.16% and 27.44% lower than those of the embodiment, respectively.

[0038] Table 4 shows the ICP analysis results of Example 1 and Comparative Example 2. From the results, it can be seen that the element Ti content of Comparative Example 2 is less than 5.0 mg / Kg, which is extremely low. Therefore, it can be judged that Comparative Example 2 does not have the oxygen vacancy lattice coordination effect unique to titanium pyrophosphate, nor does it have a three-dimensional structure composed of corner-sharing TiO6 octahedrons and PO4 tetrahedrons, and cannot be K + Storage provides a large space, making K + It is not easy to lose and has no Ti-W bond, so the absence of titanium pyrophosphate leads to lower methanol conversion rate and methyl sulfide selectivity in Comparative Example 2.

[0039] It can be seen from Table 4 that Comparative Example 3 does not contain potassium alcohol compounds (K < 5.0 mg / Kg). From the catalyst evaluation results in Table 1, the CO, CO2, and CH4 of Comparative Example 3 are 9.29%, 1.55%, and 1.35%, respectively, which are much higher than 0.06%, 0.05%, and 0.03% of Example 1, and the selectivity of dimethyl sulfide is 68.66%, which is very poor.

[0040] Comparing the data in Table 1 and Table 2, after 500 hours of evaluation, the methanol conversion rate, methyl sulfide selectivity and methyl sulfide yield of Example 3 were reduced by 0.26%, 0.16% and 0.41%, respectively, while the methanol conversion rate, methyl sulfide selectivity and methyl sulfide yield of Comparative Example 1 were reduced by 6.42%, 5.05% and 8.32% after 500 hours of evaluation; the methanol conversion rate, methyl sulfide selectivity and methyl sulfide yield of Comparative Example 2 were reduced by 5.38%, 2.40% and 6.27% after 500 hours of evaluation; the methanol conversion rate, methyl sulfide selectivity and methyl sulfide yield of Comparative Example 3 were reduced by 8.91%, 12.07% and 15.74% after 500 hours of evaluation, respectively, which fully shows that the catalyst prepared by this scheme is more stable and has a longer service life.

[0041] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A catalyst for synthesizing methyl sulfide from hydrogen sulfide and methanol, characterized in that: The catalyst comprises a carrier and an active component in a mass ratio of 1:0.1-1; The carrier comprises pseudo-boehmite, aminosulfonic acid compound and titanium pyrophosphate, and the mass ratio of the pseudo-boehmite, aminosulfonic acid compound and titanium pyrophosphate is 90-99:0.5-5:0.5-5; The active components include soluble tungsten-containing compounds, potassium alcohol compounds and ammonia water, and the mass ratio of the soluble tungsten-containing compounds, potassium alcohol compounds and ammonia water is 1:0.1-1:1-2.

2. The catalyst for synthesizing methyl sulfide from hydrogen sulfide and methanol according to claim 1, characterized in that: The aminosulfonic acid compound is at least one of aminosulfonic acid, 2-aminoethanesulfonic acid or 3-aminopropanesulfonic acid; the concentration of the ammonia water is 20-30%.

3. The catalyst for synthesizing methyl sulfide from hydrogen sulfide and methanol according to claim 1, characterized in that: The soluble tungsten-containing compound is at least one of silicotungstic acid, sodium tungstate, lithium tungstate, potassium tungstate, ammonium metatungstate, ammonium paratungstate, cesium tungstate, tungsten nitride or sodium phosphotungstate; the potassium alcoholate compound is at least one of potassium methoxide, potassium ethoxide or potassium tert-butoxide.

4. The method for preparing a catalyst for synthesizing methyl sulfide from hydrogen sulfide and methanol according to any one of claims 1 to 3, characterized in that: The steps include: Step 1 is to mix pseudo-boehmite, aminosulfonic acid compound, titanium pyrophosphate and a first portion of deionized water to obtain a first material, granulate the first material to obtain first particles, and dry and calcine the first particles to obtain a carrier; Step 2 is to disperse the soluble tungsten-containing compound, the potassium alcoholate compound and the ammonia water in the second portion of deionized water to obtain an impregnation solution; Step 3 is to immerse the carrier obtained in step 1 into the impregnation solution obtained in step 2 to obtain a carrier, and dry the carrier to constant weight to obtain the catalyst for synthesizing methyl sulfide from hydrogen sulfide and methanol.

5. The method for preparing a catalyst for synthesizing methyl sulfide from hydrogen sulfide and methanol according to claim 4, characterized in that: The temperature of the drying step in step 1 is 80-120°C; the temperature of the calcining step in step 1 is 300-500°C.

6. The method for preparing a catalyst for synthesizing methyl sulfide from hydrogen sulfide and methanol according to claim 4, characterized in that: The mass of the first portion of deionized water in step 1 is 50% of the mass of the pseudo-boehmite.

7. The method for preparing a catalyst for synthesizing methyl sulfide from hydrogen sulfide and methanol according to claim 4, characterized in that: The mixing step in step 1 is carried out by using a kneader; the granulation step in step 1 is carried out by using an extruder and a ball rolling machine.

8. The method for preparing a catalyst for synthesizing methyl sulfide from hydrogen sulfide and methanol according to claim 4, characterized in that: The temperature of the dispersion step in step 2 is 40-90°C.

9. The method for preparing a catalyst for synthesizing methyl sulfide from hydrogen sulfide and methanol according to claim 4, characterized in that: The time of the impregnation step in step 3 is 0.5-24h.

10. The method for preparing the catalyst for synthesizing methyl sulfide from hydrogen sulfide and methanol according to claim 4, characterized in that: The temperature of the drying step in step 3 is 80-120°C.

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