Heteropolyacid catalyst and preparation method thereof

Abstract

The invention provides a heteropolyacid catalyst and a preparation method thereof. The chemical formula of the catalyst is as follows: PaMo12VbAcBdCeDfOg. Solid heat-conduction powder is added to an aqueous solution containing phosphorus, molybdenum and alum, so that molybdovanadophosphoric acid generated in a reaction is attached to the surface of the solid heat-conduction powder, then other saline solutions are added, and heteropolyacid deposition layers are uniformly supported on surfaces of solids. The catalyst with good product selectivity, long service life and high mechanical strength is obtained through drying, roasting, forming and other procedures. The catalyst obtained with the preparation method can be applied to selective oxidation preparation of methacrylic acid through methylacrolein.

Description

technical field [0001] The invention relates to a preparation method of a heteropolyacid salt catalyst and its application in the reaction of preparing methacrylic acid through the selective oxidation of methacrolein. Background technique [0002] Methyl methacrylate (MMA) is an important chemical intermediate, mainly used in the production of plexiglass, and can also be polymerized with other monomers to form copolymers, used for coating modifiers, polyvinyl chloride modifiers and Medical polymer materials, etc. At present, the production of methacrylic acid (MAA) has acetone cyanohydrin method, methacrolein method, etc. From the perspective of environmental protection and economic technology, the production of MAA with methacrolein as a raw material has a good development prospect. Using methacrolein as a raw material to prepare MAA requires the use of heteropolyacid salts as catalysts. The higher activity of the catalysts can easily cause peroxidation and reduce the yiel...

AI Technical Summary

Problems solved by technology

[0004] Although the above various improvement methods have been adopted, due to the large particle size and small specific surface area of ​​the catalyst prepared by the co-precipitation method, the local heat accumulation in the reaction process is still relatively serious, which not only causes the overoxidation of the reactants, but also makes the catalyst Decomposition and inactivation seriously restrict the improvement of industrial production efficiency

In order to avoid the occurrence of the above consequences, measures of low-concentration reactants are generally adopted in actual production, which in turn leads to a further reduction in production efficiency.