Pyridyl rhodium catalyst and its preparation method and application

Abstract

A kind of pyridyl rhodium catalyst, described pyridyl rhodium catalyst is made of pyridyl-containing compound and Rh 2 (CO) 4 x 2 Coordination formation, wherein, X is Cl or I. The present invention uses Rh 2 (CO) 4 x 2 With the compound raw material containing pyridyl group, Rh-N and Rh-O coordination bonds are formed between rhodium carbonyl and the compound containing pyridyl group, so that rhodium is coordinated with the compound containing pyridyl group, and a stable pyridine structure is obtained. rhodium-based catalysts. The pyridyl rhodium catalyst maintains the stability of the catalyst by containing pyridine groups, so that the catalyst is not easy to decompose and precipitate to cause deactivation, and the stability of the catalyst is improved by adding ligands on the basis of the rhodium-based catalyst to maintain its activity. In addition, in this reaction, methanol and CO are used as raw materials to synthesize acetic acid. In the reaction, not only the conversion rate of methanol is high, but also only acetic acid is selectively produced, which solves the problems of many by-products and low selectivity of acetic acid in the carbonylation process. The invention also provides the preparation method and application of the pyridyl rhodium catalyst.

Description

Technical field: [0001] The invention relates to the technical field of preparing acetic acid by carbonylation, in particular to a pyridyl rhodium catalyst and a preparation method and application thereof. Background technique: [0002] Acetic acid is an important basic organic chemical product. As an important organic raw material and an excellent organic solvent, it is widely used in industries such as chemical industry, light textile, plastic, medicine, rubber and dyestuff. [0003] At present, as far as the acetic acid production process in the world is concerned, the acetic acid production process of methanol carbonylation has become the global acetic acid production process, and the Monsanto production technology has also become the mainstream process of its acetic acid production. Monsanto production process is based on [Rh(CO) 2 I 2 ] – As the catalytic active center, the reaction conditions are 150-200°C, the pressure is 3-6MPa, and the reaction conditions are re...

AI Technical Summary

Problems solved by technology

But there are also some problems in the rhodium-iodine catalyst in the Monsanto process, the catalyst active center [Rh(CO) 2 I 2 ] – The interaction with HI in the system will form [Rh(CO) 2 I 3 H] – , [Rh(CO) 2 I 3 H] – Then react with HI to form [Rh(CO) 2 I 4 ] – Causes the price change of the active center of the catalyst

Therefore generally need to add the water of mass fraction 14-16% to accelerate [Rh(CO) 2 I 4 ] – To [Rh(CO) 2 I 2 ] – The conversion of the catalyst improves the stability of the catalyst and maintains the activity of the catalyst. However, a high content of water will lead to the occurrence of water-gas shift side reactions in the middle of the reaction system, the conversion rate will decrease, and the cost will be increased in the later product separation process.

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