Preparation method of methyl methacrylate

Abstract

The invention discloses a preparation method of methyl methacrylate, wherein the method comprises the steps: adding methylacrolein and methanol into an airtight continuous reactor, and sufficiently mixing until the mass concentration of methanol in the mixture is 45-80%; and adding a gold-based catalyst into the reactor in a stirring state, introducing an oxidant into the bottom of the reactor, controlling the reaction temperature to be 110-160 DEG C and the reaction pressure to be 0.5-2 MPa, and carrying out catalytic oxidation esterification to prepare methyl methacrylate. The preparation cost of the catalyst is reduced, the wear resistance of the catalyst is improved, the preparation conditions are more environment-friendly, and the catalytic activity is good. The methyl methacrylate product synthesized by catalysis has high yield and is not easy to polymerize in a reaction system.

Description

technical field [0001] The invention belongs to the technical field of catalytic synthesis, and in particular relates to a preparation method of methyl methacrylate. Background technique [0002] Methyl methacrylate (MMA) is an important organic chemical raw material. It is a colorless and transparent liquid with ether fragrance at room temperature. It is mainly used to produce plexiglass and resin materials. At present, the production technology of producing MMA in the world mainly includes the acetonitrile alcohol method and the isobutylene method (three-step reaction), but these technological processes have the shortcomings of large energy consumption and much pollution. Considering environmental protection and economic benefits, developing new The process route is very necessary. [0003] Using air or oxygen as an oxidant to directly oxidize methacrolein and methanol into the target product MMA in one step is undoubtedly a simple, green and economically competitive proc...

AI Technical Summary

Problems solved by technology

Among them, the catalyst used in CN109395732 patent is SiO 2 -Al 2 o 3 As a carrier, a large amount of nitric acid is introduced in the preparation process, and the precursor of alumina is aluminum nitrate, which causes a large amount of NOx to be produced in the subsequent roasting process, consumes a lot of energy and is not environmentally friendly, and the economy is poor

The reaction of co-oxidation of methacrolein and methanol to MMA is a gas-liquid-solid three-phase reaction. In the reaction, air or oxygen exists in a large amount as oxides in the reaction, so the catalyst is inevitably collided and worn during the reaction, and the active center falls off. phenomenon, which is the direct cause of the decline in catalyst activity; in addition, the polymerization and attachment of the product MMA in the reaction system makes the active center covered, which is also the cause of the decline in catalyst activity.

Images