Application of load type catalyst in synthesizing N phenyl maleimide

Abstract

An application of a carried catalyst in synthesizing the N-phenyl maleimide from N-phenyl maleamidic acid by cyclizing reaction is disclosed. Said carried catalyst is prepared through immersing the carrier chosen from metallic oxide, zeolite molecular sieve, and their mixture in the aquatic solution containing the salt of Fe, Ni, Co, or Cu, drying and calcining.

Description

technical field [0001] The invention belongs to the application field of supported catalysts in special fine chemical products, and in particular relates to the application of a supported catalyst in synthesizing N-phenylmaleimide. Background technique [0002] N-phenylmaleimide is an important fine chemical product, mainly used as acrylonitrile-butadiene-styrene (ABS), polyvinyl chloride (PVC), methyl methacrylate (MMA) and other resins Heat-resistant, wear-resistant, pressure-resistant and other modifiers, and intermediates for medicines, pesticides, etc., so it is a very important compound. [0003] The preparation of N-phenylmaleimide usually adopts maleic anhydride and aniline compound to carry out ring closure reaction in dehydrating agent to obtain target product, as the reaction process described in U.S. Patent US2444536, dehydration in the method adopted Used a large amount of acetic anhydride in the agent, produced a large amount of acetic acid waste waters thus, ...

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Problems solved by technology

In Japanese Patent JP53-68770, the above-mentioned method has been improved. In the ring-closing reaction, an aprotic solvent and an inorganic acid (such as: phosphoric acid, concentrated sulfuric acid, p-toluenesulfonic acid and phosphorus pentoxide) are used to catalyze Dehydration, the disadvantage of this method is the use of expensive and toxic aprotic polar solvents such as dimethylformamide, which increases production costs

Due to the use of an acid catalyst, the loss of the solvent is relatively large, and it is very difficult to completely remove it from the product due to the high boiling point

Described in the Japanese patent JP60-11465 is the preparation method of the N-phenylmaleimide that takes strong acidic ion exchange resin as catalyzer, the use amount of catalyzer is bigger in this method, and catalyzer itself is expensive

In U.S. Patent No. 4,400,521, it is described that metal oxides (such as zinc oxide, magnesium oxide, cobalt oxide, nickel oxide, copper oxide) and their salts (such as: organic acids, inorganic acid salts) are used as catalysts. The use of catalyst avoids the use of high boiling point solvents and reduces the reaction temperature, but the amount of catalyst used is relatively large and difficult to recycle

Recently in U.S. Patent US4705866 and Japanese Patent JP flat 4-295462, organotin compounds (such as: SnX 2 , SnAc 2 etc.) as the report of novel catalyst preparation N-phenylmaleimide, but this kind of catalyzer is expensive and very toxic, and source is difficult, is unfavorable for large-scale production