Allantoin synthesizing process

Abstract

The invention relates to a new technique to prepare allantoin, in a stirring state, adding hydrogen peroxide solution containing a proper amount of metallic salt catalyst or resin loading metallic salt catalyst to oxalic dialdehyde water solution, to oxidize the oxalic dialdehyde into glyoxalic acid; adding a proper amount of raw material urea to the obtained glyoxalic acid solution and completing catalytic condensation reaction under the condition of heating and stirring; filtering and recovering the catalyst, cooling, pump-filtering, washing, recrystallizing and drying to obtain the finished product allantoin. It has larger yield at 56% or so; reduces the urea dosage; the new catalyst is simple to prepare and has high catalytic activity, able to be repeatedly used for 10 times above; it is a new green technique.

Description

technical field [0001] The invention relates to a new synthesis process of allantoin. Background technique [0002] Allantoin is a fine chemical, which has a wide range of uses in medicine, cosmetics, biochemistry and other fields. The Chinese Patent Office published on August 19, 1998 the title "Method for One-Step Synthesis of Allantoin from Glyoxal", patent application number: 99115646.3 and the publication on May 30, 2001 called "The Synthetic Process of Allantoin" , patent application number: 98111144.0 patent application, all is the method that adopts inorganic acid catalytic oxidation glyoxal to synthesize allantoin, it exists acid consumption and acid solution pollution are big, equipment corrosion is serious, catalyst can not be reused etc. problems. [0003] At present, the literature reports that in the production process of allantoin prepared by the solid acid catalyzed glyoxal oxidation method, the metal oxide Fe 2 o 3 / SO 4 2- ,TiO 2 / SO 4- , ZrO 2 / SO ...

AI Technical Summary

Problems solved by technology

The Chinese Patent Office published on August 19, 1998 the title "Method for One-Step Synthesis of Allantoin from Glyoxal", patent application number: 99115646.3 and the publication on May 30, 2001 called "The Synthetic Process of Allantoin" , patent application number: 98111144.0 patent application, all use inorganic acid to catalyze the oxidation of glyoxal to synthesize allantoin, which has problems such as large acid consumption and acid pollution, serious equipment corrosion, and catalysts that cannot be reused.

[0003] At present, the literature reports that in the production process of allantoin prepared by the solid acid catalyzed glyoxal oxidation method, the metal oxide Fe 2 o 3 / SO 4 2- ,TiO 2 / SO 4- , ZrO 2 / SO 4 2- , Inorganic acids such as phosphotungstic acid or solid superacids catalyze the condensation reaction of urea and glyoxylic acid. Although the acid pollution is eliminated, there is still a large amount of catalyst (9%), high energy consumption and complicated process for catalyst preparation. Such as soaking in sulfuric acid for 12 hours, roasting at 600 ° C, etc., and the catalytic activity is low, easy to deactivate, the number of repeated use is not more than 4 times, the excess of urea is large, the reaction time is long, and the yield of allantoin is low.