Authors: Yu.A. Matrosova, S.A. Prokhorov, I.V. Oshanina

Title of the article: Preparation of dimethylmaleate by oxidative carbomethoxylation of acetylene

Year: 2025, Issue: 1, Pages: 70-78

Branch of knowledge: 2.6.10. Organic matter technology

Index UDK: 66.095.135 + 541.128

DOI: 10.26730/1999-4125-2025-1-70-78

Abstract: Dimethyl ether of maleic acid is a product of basic organic synthesis, which used for the production of a number of solvents, plastics, polymeric materials, etc. The reaction of acetylene oxidative carbmethoxylation is one of the methods of its synthesis. Passing a mixture of carbon monoxide, acetylene and oxygen through the PdBr2 – LiBr – PcCo – methanol catalytic system makes it possible to produce dimethyl maleate with high selectivity. The process also produces a small amount of fumaric acid dimethyl ester. To optimize the catalytic system composition and the dimethyl maleate production conditions, the effect of palladium bromide concentration and acetylene partial pressure on the process characteristics was studied. A comparative analysis of the activity of cobalt and iron phthalocyanates was also carried out. The result of the effect of palladium bromide concentration on the reaction rate showed that the dependence is complex. The different activity of monomeric and dimeric palladium complexes formed in the contact solution may be the reason for the complex nature of the dependence. The results of experiments with varying the partial pressure of acetylene in the reactor (in the range of 4-15 kPa) allow us to conclude that the reaction order for acetylene is zero. This fact is especially important for safe handling of acetylene in industrial environments. A comparison of the activity of cobalt and iron phthalocyanates showed that the rates of products accumulation and the selectivity of their formation are higher when using PcCo as a component of the catalytic system. The use of binary solvents (methanol and nitrile) leads to a decrease in the rate of dicarboxylic acids ester formation. Interesting results were obtained when working with substituted iron phthalocyanine in a binary solvent. The paper contains recommendations on the optimal composition of the catalytic system. The feasibility of introducing an additional high-boiling solvent into the multifunctional catalytic system is discussed.

Key words: dimethylmaleate oxidative carbmethoxylation of acetylene carbon monoxide palladium bromide complexes cobalt (iron) phthalocyanine acetonitrile adipodinitrile

Receiving date: 22.11.2024

Approval date: 22.01.2025

Publication date: 12.03.2025

CITE DOWNLOAD