Pyridyl rhodium catalyst and preparing method and application thereof

Abstract

A pyridyl rhodium catalyst is provided which is formed by coordination of a pyridyl-containing compound and Rh2(CO)4X2 in which X is Cl or I. The Rh2(CO)4X2 and the pyridyl-containing compound that isa raw material are adopted to form Rh-N and Rh-O coordinate bonds between carbonyl rhodium and the pyridyl-containing compound, so that rhodium and the pyridyl-containing compound are coordinated toobtain the pyridyl rhodium catalyst with a stable structure. Stability of the catalyst is maintained by the pyridyl group so that decomposition and precipitation which cause deactivation of the catalyst are not liable to occur. The stability of the catalyst is improved through adding a ligand on the basis of a rhodium catalyst so as to maintain activity. In addition, methanol and CO are adopted asraw material to synthesize acetic acid, the reaction has a high methanol conversion rate and high selectivity so that only acetic acid is generated, thus solving a problem that a carbonylation process has many side products and low acetic acid selectivity, and the like. The invention also provides a preparing method and application of the pyridyl rhodium catalyst.

Description

[0001] Technical field: [0002] 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. [0003] Background technique: [0004] 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. [0005] 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 co...

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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