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EP-4741054-A1 - A CATALYST FOR THE PRODUCTION OF ACETIC ACID AND METHYL ACETATE FROM CO2 AND CH4 BASED ON ZEOLITES WITH CONTROLLED DISTRIBUTION OF ALUMINUM ATOMS

EP4741054A1EP 4741054 A1EP4741054 A1EP 4741054A1EP-4741054-A1

Abstract

A catalyst based on zeolite with a controlled distribution of aluminium atoms in the zeolite structure and with a specific location of divalent transition metal cations, such as iron and zinc cations, in the zeolite and a method for producing acetic acid and methyl acetate from carbon dioxide and methane using such a catalyst are disclosed. The structure of the zeolite is selected from CHA, FER, MOR and *BEA.

Inventors

  • TARACH, Karolina
  • GÓRA-MAREK, Kinga
  • Sobalska, Julia
  • TABOR, Edyta
  • DEDECEK, JIRI
  • Mlekodaj, Kinga
  • Kaucký, Dalibor

Assignees

  • UNIWERSYTET JAGIELLONSKI
  • Czech Academy of Sciences

Dates

Publication Date
20260513
Application Date
20251108

Claims (4)

  1. A catalyst for the production of acetic acid and methyl acetate from methane and carbon dioxide, characterized in that it comprises a zeolite containing: - Al atoms arranged in pairs, wherein each pair is represented by two Al atoms located in one zeolite ring, - cations of a divalent transition metal M, preferably Fe and Zn, wherein the ratio of transition metal M to Al is in the range of 0.06 to 0.45, the weight content of transition metal M is less than 10% by weight, and the Si/Al ratio of the zeolite is in the range of 2.5 to 10, wherein the zeolite has a structure selected from CHA, FER, MOR, or *BEA structures determined according to the Nickel-Strunz classification of zeolite structures.
  2. A method for producing acetic acid and methyl acetate, characterized in that : a) water and ammonium ions are removed from the catalyst, preferably by heating for a period longer than 30 minutes at a temperature above 300 °C, wherein a catalyst according to the invention as defined above is used, b) the catalyst is contacted first with methane and subsequently with carbon dioxide at temperatures below 450 °C under at least atmospheric pressure (1 atm.).
  3. The method according to claim 2, characterized in that in step (a) the heating is carried out under vacuum or in a stream of an inert gas, preferably helium or nitrogen.
  4. The method according to claim 2, characterized in that in step (a) the heating is carried out at a temperature of at least 500 °C.

Description

The object of the invention is a method for obtaining a zeolite-based catalyst with a controlled distribution of aluminum atoms, ensuring the desired location of transition metal cations, and the use of such a catalyst for the conversion of methane and carbon dioxide into acetic acid and methyl acetate. Carbon dioxide and methane are gases that significantly contribute to the greenhouse effect. High concentrations of CO2 in the atmosphere have a direct impact on global warming and ocean acidification. Therefore, the transformation of CO2 into chemical compounds that can be further used as valuable substrates in the chemical industry is an ideal solution to reduce the amount of CO2 in the environment. Methane, the main component of shale gas, is a promising starting material for the production of fuels and chemicals.1-4 Therefore, using CO2 and CH4 as raw materials for the production of value-added chemicals is an attractive method for efficiently utilizing shale gas while simultaneously reducing atmospheric CO2 concentrations. Acetic acid is a crucial product for the food industry and an important intermediate for many commercial chemicals, such as acetic anhydride, vinyl acetate, and alkyl acetates. It can also be used as a solvent in the synthesis of terephthalic acid.5-7 It is one of the most important industrial chemicals used in the manufacture of volatile organic esters, such as ethyl and butyl acetates, vinyl acetate, cellulose acetate, and metal acetates. The growing use of acetic acid in terephthalic acid production is expected to support market expansion. In the manufacture of polyester resins, which are widely used in polyester films, PET resins, and polyester fibers, terephthalic acid plays a key role as a building block component. Terephthalic acid is also used in the fabrication of textiles. Vinyl acetate monomers, produced from acetic acid, are often used to make resins and polymers used in textiles, paints, coatings, adhesives, and films. Many technological processes for obtaining acetic acid have been developed based on various reactions, including: (i) partial oxidation of CH4 with oxygen and subsequent reaction with carbon monoxide,8-10 (ii) selective oxidation of ethane with oxygen,11,12 (iii) oxidation of ethanol,13-15 or (iv) carbonylation of methanol16-20 and fermentation.21 Among these processes, carbonylation of methanol is the most widely used in industry. The industrial synthesis of acetic acid began with the BASF process and was later improved by the Monsanto process22 and the Cativa process.23 The BASF process of methanol carbonylation used high pressure (approximately 68 MPa) and a cobalt-based catalytic system promoted by iodide ions. The Monsanto process used a homogeneous Rh catalyst, which enabled the synthesis of acetic acid with high selectivity (>99%) at a pressure of approximately 3-6 MPa and a temperature of 150-200 °C. The Cativa process was developed using a more active Ir-based catalyst,24,25 which resulted in fewer side products. The optimal solution is therefore the direct conversion of CH4 and CO2 into acetic acid, a process that is environmentally friendly and aligns with the principles of green chemistry. However, the direct transformation of methane and carbon dioxide into acetic acid is thermodynamically unfavorable; hence, the use of a catalyst is necessary. For example, Taniguchi and co-workers26 studied the reaction between methane and carbon dioxide using a vanadium catalyst in a solution containing trifluoroacetic acid (TFA) and peroxydisulfate (as an oxidant). The yield of this reaction was 15.7% based on CH4. The study showed that the reaction yield was independent of CO2 pressure and that the reaction proceeded without the participation of CO2. This suggests that acetic acid was not formed by the reaction between CO2 and CH4. Huang and co-workers27 employed a periodic method for obtaining acetic acid using a Co-Cu Cu/Co5 catalyst; however, the composition and properties of the catalyst were not precisely specified. Initially, the catalyst was exposed to methane, which, according to the authors, generates a CHx group on the surface; then, the gas flow was changed to CO2. This process was repeated several times. Apart from acetic acid, other products were formed (alcohols, ketones, formic acid, and cyclopentane derivatives), and the reaction yield was not reported. The selectivity toward acetic acid was 21%. Esther M. Wilcox and co-workers28 monitored the interaction between CO2 and CH4 over 5% Pt/Al2O3 and 5% Pd/carbon catalysts. Studies using FTIR spectroscopy and temperature-programmed reduction confirmed the formation of acetic acid from a mixture of CO2 and CH4 at a temperature of approximately 400 °C. In turn, the patent by Freund and Wambach29 claims a method for the direct synthesis of acetic acid from CO2 and CH4 using a solid catalyst described as containing "one or more metals from groups VIA, VIIA, VIIIA" supported on alumina, aluminum hydro