Process for preparing methyl methacrylate according to aldol condensation method

Abstract

The invention relates to production of methyl methacrylate, in particular to a process for preparing methyl methacrylate according to an aldol condensation method, wherein the process is realized by connecting multiple reactors in series and in parallel. According to the process, the multiple reactors are connected in series, and a methyl propionate stream and multiple formaldehyde streams are fed, so that the effective conversion rate of a raw material formaldehyde can be well increased, and the single-cycle service life of a catalyst can be prolonged; the reactors of two series are connected in parallel, so that regeneration operation over the catalyst which is deactivated is realized without shutdown, and the whole system can run normally. Compared with the prior art, the process has the advantages that unfavorable factors such as the short service life of the aldol condensation catalyst and the high requirement on the catalyst during use of a fluidized bed are well eliminated, and the process has high application value and good economic benefits.

Description

technical field [0001] The invention relates to a production process of methyl methacrylate, in particular to a process for preparing methyl methacrylate by an aldol condensation method with long catalyst service life and high raw material utilization rate. Background technique [0002] Methyl methacrylate (MMA) is an important organic chemical raw material, mainly used in the production of plexiglass (PMMA), and also widely used in the production of resins, plastics, coatings, adhesives and various industrial additives. From 2009 to 2013, the production capacity and demand of my country's MMA industry both increased rapidly, and the production capacity increased from 420,000 tons / year to 590,000 tons / year, with an average annual compound growth rate of 7.0%; the demand increased from 470,000 tons / year to 690,000 tons / year, with an average annual compound growth rate of 8.0%. Domestically, demand is higher than production capacity growth. Driven by the downstream industry, ...

AI Technical Summary

Problems solved by technology

However, the alkali metal catalyst used in aldol condensation is prone to carbon formation and deactivation under high temperature conditions, thus resulting in a short service life of the catalyst. Under this condition, only the fluidized bed process application of Risun Chemical, such as CN102775302A, CN104513163A, is expected Catalyst activity recovery by continuous regeneration

However, compared with the fixed bed, the conversion rate of the fluidized bed is relatively low, and the strength of the catalyst is high, which is easy to cause catalyst pulverization and loss, and the solid particle catalyst will seriously wear the pipe and container.

At the same time, because formaldehyde is prone to side reactions and the effective utilization rate is not high, how to effectively improve the process conditions, prolong the service life of the catalyst, and increase the effective utilization rate of formaldehyde has become an important factor affecting production costs in the industrial scale-up process

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