Method for high-selectivity preparation of normal aldehyde through olefin two-phase hydroformylation on basis of phosphine-functionalized polyether imidazolium salt ionic liquid

Abstract

The invention relates to a method for high-selectivity preparation of normal aldehyde through olefin two-phase hydroformylation on the basis of a phosphine-functionalized polyether imidazolium salt ionic liquid. According to the method, a two-phase catalytic system is adopted, the catalytic system comprises a phosphine-functionalized polyether imidazolium salt ionic liquid, a polyether imidazolium salt ionic liquid, a rhodium catalyst, a reaction substrate olefin and a reaction product aldehyde, a liquid / liquid two-phase hydroformylation reaction is performed at certain reaction temperature and under certain synthesis gas pressure, the rhodium catalyst is separated and cycled through simple two-phase separation after the reaction ends, the rhodium catalyst can be recycled multiple times, and the catalytic activity and the selectivity are not remarkably reduced. The TOF value of the system reaches 400-3,300 h<-1> and the catalytic cycle accumulated TON value reaches 33,975.

Description

technical field [0001] The invention relates to the technical field of chemistry and chemical engineering, in particular to a method for preparing normal aldehyde with high selectivity by two-phase hydroformylation of olefins based on phosphine functionalized polyether imidazolium salt ionic liquid. Background technique [0002] The rhodium-catalyzed hydroformylation of olefins is a typical atom-economical reaction, and it is also a carbonylation reaction with more reports in the literature. It has become an ideal method for the preparation of high-carbon aldehydes / alcohols. Homogeneous hydroformylation has the advantages of high catalytic activity, good selectivity and mild reaction conditions, but the separation and recycling of rhodium catalysts has been the focus of attention in the field of homogeneous catalysis for a long time. [0003] In recent years, the liquid / liquid two-phase catalytic system with ionic liquid as the catalyst carrier has developed very rapidly, an...

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Problems solved by technology

Homogeneous hydroformylation has the advantages of high catalytic activity, good selectivity and mild reaction conditions, but for a long time, the separation and recycling of rhodium catalysts has been the focus of attention in the field of homogeneous catalysis

But this two-phase system still has the following problems: one is that a large amount of ionic liquid is required as the carrier of the Rh-TPPTS catalyst, and the mass ratio of the ionic liquid to the rhodium catalyst precursor reaches 1000:1; Due to the limitation of mass transfer resistance, the catalytic activity is not high, and the TOF value is only 10-200h -1 The third is that the regioselectivity of normal aldehyde is relatively poor, and the anisotropic ratio is only 2.0:1-2.4:1 (67-71% of normal aldehyde regioselectivity)

Under this system, the phosphine-functionalized ionic liquid not only has the characteristics of a phosphine ligand, can form a complex catalyst with rhodium, but also has the solvent performance of an ionic liquid, and can serve as a carrier for a rhodium catalyst, so there is no need to add a large amount of other ions liquid, which fundamentally solves the problem of high dosage of ionic liquids, and also minimizes the negative effect of ionic liquids in catalytic reactions; but the system has very poor regioselectivity of normal aldehydes (<80%)

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