Pyrazole acetic-acid rhodium complexes catalyst capable of catalyzing carbonylation reaction to preparing acetic acid and acetic anhydride and preparation method and use thereof

Abstract

The invention belongs to the field of acetic acid and acetic anhydride prepared by carbonylation synthesis, which relates to a pyrazole acetic rhodium complex catalyst used to synthesize the acetic acid by methanol carbonylation and synthesize the acetic anhydride by methyl acetate carbonylation, as well as a preparation method and applications of the catalyst. The catalyst has excellent catalytic activity and reaction stability when being used to prepare the acetic acid through catalyzing the methanol carbonylation reaction and prepare the acetic anhydride through the methyl acetate carbonylation reaction. The pyrazole acetic rhodium complex catalyst, methanol, cocatalyst methyl iodide are added into a pressurized vessel which is then input with carbon monoxide with the pressure being kept at 3 to 4MPa, the reaction temperature is between 150DEG C and 200DEG C, and the acetic acid is obtained after the agitation reaction; and the catalyst takes rhodium as an active species, and the rhodium active species and pyrazole form a unidentate coordination structure having the following structure.

Description

technical field [0001] The invention belongs to the field of synthesizing acetic acid and acetic anhydride by carbonylation, and relates to a pyrazole rhodium acetate complex catalyst for synthesizing acetic acid and acetic anhydride by carbonylation of methanol, and a preparation method and application of the catalyst. Background technique [0002] The carbonylation reaction of methanol and carbon monoxide under the action of homogeneous rhodium catalyst to prepare acetic acid was the invention of Paulik et al. (US 3 769 329) of Monsanto Company in the United States in the early 1970s. This invention opened up a new method for the carbonyl synthesis of methanol. important process routes. On this basis, later Halcon (BE 819 455) Ealtman, Ajinamoto (Japan Kokai 50 / 30,820), Showa Denko (Japan Kokai 50 / 47,922), BP (B.Von Schlotheim, Chem.Industrie 1994, 9 / 89.80) and Hoechst (DE 24 50 965) will be the same [Rh(CO) 2 I 2 ] - A breakthrough has been made in the research on the...

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Problems solved by technology

Higher activity and good selectivity are the obvious advantages of this type of catalyst; however, the instability of this type of catalyst tends to generate trivalent rhodium precipitation, especially at a higher temperature that is conducive to the reaction, or in the flash separation of part of the carbon monoxide fraction. This is especially true when the pressure is low, and the above-mentioned shortcomings have been recognized by people.

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