Method for producing N,N'-dicyclohexyl carbodiimide

Abstract

The invention discloses a preparation method of N,N'-dicyclohexyl carbodiimide. The method comprises the following steps: taking dicyclohexyl urea (DCU) and trichloromethyl carbonate (BTC) as raw materials, dissolving dicyclohexyl urea (DCU) in a solvent, uniformly stirring, cooling, adding trichloromethyl carbonate and a catalyst loaded on a molecular sieve, carrying out heat preservation reflux, cooling, adjusting the pH value to 8-9 by using alkali, filtering the reaction liquid, evaporating out the solvent, and carrying out reduced pressure distillation to obtain the product namely N,N'-dicyclohexyl carbodiimide. According to the present invention, the problems of strong odor, strong toxicity and heavy environmental pollution of the traditional process are fundamentally eliminated, and the method has characteristics of high safety coefficient, partial catalyst recycling, high catalysis efficiency, partial raw material recycling, less three wastes, high purity and high yield, and is suitable for industrial production.

Description

technical field [0001] The invention belongs to the field of organic synthesis, in particular to a method for producing N,N'-dicyclohexylcarbodiimide. Background technique [0002] N,N'-dicyclohexylcarbodiimide, also known as DCC, is a colorless and transparent solid, liquid above 35°C, it has a wide range of uses, and is often used in laboratories to synthesize aldehydes, anhydrides, amino acids, ketones, esters and other compounds low temperature dehydrating agent. It is also a dehydrating agent commonly used in industrial organic synthesis and medicine. It is mainly used in the production of amikacin and glutathione in my country. [0003] In the prior art, the chemical synthesis method of N,N'-dicyclohexylcarbodiimide mainly involves the following methods: thiourea method, urea method, isocyanate method and phosgene method. [0004] There are two synthetic methods in the thiourea method. The first method is to use mercury oxide as a reaction reagent. Mercury oxide is a...

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Problems solved by technology

The use of relatively safe solid phosgene in this process can effectively ensure safety and environmental protection, and fundamentally eliminate the problem of serious pollution of the three wastes, but the yield of this process is not stable enough and the yield is not high enough, which will adversely affect future industrial production

[0009] The patent of CN 103922970 A discloses a production process of dicyclohexylcarbodiimide, which is to add solid phosgene to dicyclohexyl urea, and then add catalyst and reaction auxiliary agent. After the reaction is completed at 35-40°C, pass Add ammonia gas to adjust the pH to 7.5-9, distill under reduced pressure to obtain the target product, use ammonia gas to adjust the alkali, the smell is strong, the pressure on environmental protection is high, and the gas is not easy to control, and it is difficult to industrialize production

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