Synthesis method of propionaldehyde by low-pressure carbonyl of ethylene

Abstract

The invention provides a synthesis method of propionaldehyde by low-pressure carbonyl of ethylene, belonging to a preparation method of saturated compound which contains -CHO group and is connected with a noncyclic carbon atom. The synthesis method comprises the steps of: taking ethylene, carbon monoxide and hydrogen as raw materials, adopting a rhodium / phosphonium complex catalyst system, and synthesizing the propionaldehyde by ethylene hydrogen formylation reaction. The synthesis method is characterized by comprising a synthesis operating unit and a rectification operating unit, wherein thesynthesis operating unit comprises a compressor, a synthesis reactor, a coarse propionaldehyde collecting tank and a gas stripping column; an entrainment separator is respectively arranged above the synthesis reactor and the coarse propionaldehyde collecting tank; and an iron-free propionaldehyde solution catalyst system of metal rhodium catalyst and ligand triphenylphosphine is used, the rhodiumconcentration in the catalyst solution is 80ppm-150ppm, and the weight percentage concentration of the triphenylphosphine is 1.5%-3%. The synthesis method of the propionaldehyde by the low-pressure carbonyl of the ethylene is simple in equipment, less in investment, simple in technological operation, and small in catalyst consumption. Counting as the ethylene, the raw material conversion rate is more than or equal to 90%, and the propionaldehyde product content is more than or equal to 99.5%.

Description

technical field [0001] The invention relates to a method for producing propionaldehyde by carbonylation of ethylene at low pressure. It belongs to the preparation of saturated compounds containing -CHO groups connected to non-ring carbon atoms. Background technique [0002] Propionaldehyde is widely used in pharmaceuticals, pesticide raw materials, coatings, plastics, food, feed additives, and leftover textile auxiliaries. Moreover, in recent years, the demand for propionaldehyde products in domestic and foreign markets has been increasing. [0003] The industrial production method of propionaldehyde mainly adopts the oxidation of propylene to produce propionaldehyde by-product of acetone, the isomerization of propylene oxide to synthesize propionaldehyde, the high-pressure carbonylation of ethylene and the low-pressure carbonylation of ethylene. Among them, the ethylene low-pressure oxo synthesis route adopts more technological methods due to its low equipment cost, low p...

AI Technical Summary

Problems solved by technology

[0005] 1. It needs to invest a huge amount of equipment for the separation of the catalyst and the product propionaldehyde, the equipment investment is large, and the process operation is cumbersome

[0006] During the separation process of the catalyst and the product acetaldehyde, the mixed material is heated repeatedly, the catalyst is easily decomposed and deactivated, and it will also cause the loss of the catalyst, resulting in catalyst consumption big

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