Method for preparing methyl methacrylate through aldol condensation of methyl propionate and formaldehyde and multi-stage reaction system

Abstract

The invention provides a method for preparing methyl methacrylate through aldol condensation of methyl propionate and formaldehyde and a multi-section reaction system. The multi-section reaction system at least comprises three sections of reactors, raw material gas can respectively enter each section of reactor and react under the action of a catalyst to generate methyl methacrylate. In the production process, at least two sections of reactors in the multiple sections of reactors are used for catalytic reaction, and generated products can enter a reaction product header pipe at the same time;at least one section of the reactor is regenerated in situ; and when the activity of the catalyst in the reactor is reduced to a preset percentage, the reactor performs in-situ regeneration. The molarfraction of the methyl methacrylate after the product generated by the multi-section reactor enters the reaction product main pipeline and is mixed is 5.0%-7.5%. According to the method and the system, the variation amplitude of the reaction product composition in the initial stage and the final stage of the reaction can be effectively reduced, the stability of the product quality is ensured, andthe operation load of the subsequent separation process is reduced.

Description

technical field [0001] The invention belongs to the technical field of methyl methacrylate synthesis, and in particular relates to a method for preparing methyl methacrylate by condensation of methyl propionate and formaldehyde aldol and a multi-stage reaction system used in the method. Background technique [0002] Methyl methacrylate (MMA) is an important organic chemical raw material, which is mainly used in many production fields such as organic glass (PMMA), resin, coating, and adhesive. At present, the most important MMA production technology, acetone cyanohydrin method (ACH method), has a tendency to be eliminated due to backward technology and serious environmental pollution. The newly developed MMA preparation technologies include Mitsubishi's isobutylene oxidation method, BASF's ethylene method, Lucite's alpha method, etc. The common feature of these technologies is that the process is relatively simple and safe and environmentally friendly. Among them, the alpha ...

AI Technical Summary

Problems solved by technology

Using a circulating fluidized bed, the pulverization and running loss of the catalyst are serious, and the annual consumption of the catalyst is huge. Combined with the characteristics of low reaction conversion rate and easy carbon formation of the catalyst, it will directly lead to high production and operation costs. The structure of the fluidized bed is complex and the cost of equipment is high. From an economic point of view, the circulating fluidized bed is not suitable for the preparation of MMA by the aldol method

In the fixed bed switching reaction regeneration mode, with the intensification of catalyst deactivation, the composition of the reaction product changes greatly in the early and late stages, which brings certain challenges to the subsequent separation operation and is not conducive to the long-term stable operation of the device.

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