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CN-121972217-A - Pyridine modified hydrogen mordenite catalyst for dimethyl ether carbonylation and one-step synthesis method thereof

CN121972217ACN 121972217 ACN121972217 ACN 121972217ACN-121972217-A

Abstract

The invention relates to the technical field of catalysts, in particular to a pyridine modified hydrogen mordenite catalyst for dimethyl ether carbonylation and a one-step synthesis method thereof. The one-step synthesis method comprises the steps of mixing a silicon source and an aluminum source according to a silicon-aluminum ratio of 12-14, adding an amine source, adjusting the pH value to about 10.5, adding a pyridine modifier accounting for 3-5% of the total mass of the aging liquid after aging, and directly obtaining the pyridine modified hydrogen mordenite catalyst through hydrothermal crystallization, washing and drying. The method does not need the traditional ammonium exchange, high-temperature roasting and post-modification steps, synchronously completes molecular sieve crystallization, hydrogen conversion and pyridine in-situ modification in a single hydrothermal system, remarkably simplifies the process flow and reduces the production cost. The catalyst prepared by the method is of a pure-phase mordenite structure, has excellent catalytic performance in dimethyl ether carbonylation reaction, does not contain noble metal and halogen, avoids equipment corrosion risk, and has good industrial application prospect.

Inventors

  • ZHANG HANXIN
  • JIANG HAILONG

Assignees

  • 高化学（江苏）化工新材料有限责任公司

Dates

Publication Date
20260505
Application Date
20251209

Claims (5)

  1. 1. A one-step synthesis method of pyridine modified hydrogen mordenite catalyst for dimethyl ether carbonylation, which is characterized by comprising the following steps: S1, mixing raw materials, namely mixing a silicon source and an aluminum source according to a silicon-aluminum ratio of 12-14 in a constant-temperature water bath environment at 20-30 ℃ and mechanically stirring at a speed of 100-150 rpm until a system is uniform to obtain a first mixed solution; s2, system adjustment, namely adding an amine source into the first mixed solution, uniformly stirring, and then adjusting the pH value of the system to 10.5 by using an alkali source to obtain a second mixed solution; S3, aging treatment, namely transferring the second mixed solution to a constant temperature device, and aging for 10-20 hours at 50 ℃ to obtain an aging solution; S4, modification and crystallization, namely adding a pyridine modifier into the aging liquid, stirring and dissolving, transferring to a hydrothermal reaction kettle, and carrying out static crystallization for 24-48 hours at 150 ℃ to obtain crystallized slurry, wherein the addition amount of the pyridine modifier is 3-5% of the total mass of the aging liquid; S5, post-treatment, namely filtering the crystallized slurry, collecting a filter cake, washing the filter cake by adopting 80 ℃ hot pure water until the conductivity of the filtrate is less than or equal to 100 mu S/cm, and then drying the washed filter cake in a 120 ℃ oven for 24 hours to obtain the pyridine modified hydrogen mordenite catalyst; The synthesis method does not need the steps of ammonium exchange, roasting and post-modification, and forms H-type active forms directly in a hydrothermal system.
  2. 2. The one-step synthesis method according to claim 1, wherein the silicon source in S1 comprises silica sol and solid SiO2 powder, and the aluminum source comprises aluminum sulfate, aluminum nitrate, aluminum oxide and pseudo-boehmite.
  3. 3. The one-step synthesis method according to claim 1, wherein the amine source in S2 comprises triethylamine, tetraethylammonium hydroxide and tetrapropylammonium hydroxide, and the alkali source comprises sodium hydroxide and potassium hydroxide.
  4. 4. The one-step synthesis method according to claim 1, wherein the pyridine modifier in S4 comprises pyridine, pyridine hydrochloride and pyridine sulfate.
  5. 5. A pyridine modified hydrogen mordenite catalyst for dimethyl ether carbonylation is characterized in that the catalyst is prepared by the one-step synthesis method according to claim 1, the catalyst is of a pure-phase mordenite structure, is modified in situ by pyridine modifier and directly forms an H-type active form, and in the dimethyl ether carbonylation reaction, the catalytic performance of the catalyst meets that the conversion rate of dimethyl ether is more than or equal to 82%, and the selectivity of methyl acetate is more than or equal to 95.5%.

Description

Pyridine modified hydrogen mordenite catalyst for dimethyl ether carbonylation and one-step synthesis method thereof Technical Field The invention relates to the technical field of catalysts, in particular to a pyridine modified hydrogen mordenite catalyst for dimethyl ether carbonylation and a one-step synthesis method thereof. Background Ethanol is used as a key basic raw material and an excellent solvent in the chemical industry field, and has wide application in the processes of compound synthesis, crystallization, extraction and the like. In the current mainstream technology for synthesizing ethanol, the two-stage method of synthesis gas has the key links of generating methyl acetate by the carbonylation reaction of dimethyl ether and then converting the methyl acetate into ethanol by hydrogenation, and the overall benefit of ethanol production is directly determined by the catalytic efficiency of the carbonylation reaction because of low cost and simple and convenient flow. Mordenite (MOR) is used as a zeolite molecular sieve catalyst with optimal performance in dimethyl ether carbonylation reaction, has double acid sites of Brusselic acid and Lewis acid, and an 8-membered ring channel is a main active site in the carbonylation reaction, and the reaction mechanism is that dimethyl ether is adsorbed at the acid site to generate methoxy, and CO is inserted to form acetyl (speed control step), so that methyl acetate is finally generated. However, the existing synthesis process of the hydrogen-type MOR catalyst has the remarkable defects that Na-type MOR is required to be subjected to hydrothermal synthesis by a silicon-aluminum alkali source, NH 4 -type MOR is required to be obtained through ammonium salt exchange, the NH 4 -type MOR is required to be subjected to roasting and conversion into H-type MOR, and the pyridine reagent is subjected to four-step post-modification, so that the steps are complicated, the equipment requirement is high, and the production cost is high. Meanwhile, the conventional MOR catalyst and other types of carbonylation catalysts have short performance plates, wherein the homogeneous catalyst depends on noble metal rhodium and contains halogenides, the cost is high, equipment is corroded, products are difficult to separate, the stability of the heteropoly acid catalyst is insufficient, the conventional MOR catalyst for multi-step synthesis has the dimethyl ether conversion rate of only about 60%, the methyl acetate selectivity is about 85%, and the industrial large-scale production requirement is difficult to meet. Therefore, the development of a process capable of directly synthesizing the high-activity pyridine modified hydrogen mordenite catalyst without multi-step exchange, roasting and post-modification has important significance for promoting the efficient conversion of dimethyl ether carbonylation and the upgrading of the ethanol synthesis process. Disclosure of Invention The invention aims to provide a pyridine modified hydrogen mordenite catalyst for dimethyl ether carbonylation and a one-step synthesis method thereof, so as to solve the problems in the background art. In order to achieve the aim, the invention provides a one-step synthesis method of pyridine modified hydrogen mordenite catalyst for dimethyl ether carbonylation, which comprises the following steps: S1, mixing raw materials, namely mixing a silicon source and an aluminum source according to a silicon-aluminum ratio of 12-14 in a constant-temperature water bath environment at 20-30 ℃ and mechanically stirring at a speed of 100-150 rpm until a system is uniform to obtain a first mixed solution; s2, system adjustment, namely adding an amine source into the first mixed solution, uniformly stirring, and then adjusting the pH value of the system to 10.5 by using an alkali source to obtain a second mixed solution; S3, aging treatment, namely transferring the second mixed solution to a constant temperature device, and aging for 10-20 hours at 50 ℃ to obtain an aging solution; S4, modification and crystallization, namely adding a pyridine modifier into the aging liquid, stirring and dissolving, transferring to a hydrothermal reaction kettle, and carrying out static crystallization for 24-48 hours at 150 ℃ to obtain crystallized slurry, wherein the addition amount of the pyridine modifier is 3-5% of the total mass of the aging liquid; S5, post-treatment, namely filtering the crystallized slurry, collecting a filter cake, washing the filter cake by adopting 80 ℃ hot pure water until the conductivity of the filtrate is less than or equal to 100 mu S/cm, and then drying the washed filter cake in a 120 ℃ oven for 24 hours to obtain the pyridine modified hydrogen mordenite catalyst; The synthesis method does not need the steps of ammonium exchange, roasting and post-modification, and forms H-type active forms directly in a hydrothermal system. Preferably, the silicon source in S1 comprises silica sol and solid SiO2 po