Method for promoting purity of N,N'-dicyclohexyl carbodiimide product

Abstract

The invention relates to a method for promoting purity of N,N'-dicyclohexyl carbodiimide product. The method comprises the following steps: adding ammonium hydroxide into a DCC crude product containing solvent, controlling temperature at 0-50 DEG C, and stirring for washing; standing by for 1 hour after the ending of washing; cooling and performing suction filtration; reducing pressure and distilling, thereby acquiring high-purity DCC. Ammonium hydroxide is used for washing, so that the content of residual cyclohexyl isothiocyanate in DCC can be effectively reduced, the content of side-productcyclohexyl isothiocyanate in the product is controlled below 50ppm, the product purity is promoted and the purity is above 99.7%; a reaction system is optimized, ammonium hydroxide is used for washing and reaction occurs in a homogeneous reaction system, so that the reaction yield is increased, the DCC oxidizing yield is increased to 95% or above, and the reaction can be easily controlled; the yield is increased, so that the use ratio of raw materials is increased, the volume of wastes is reduced, investment in environmental protection is reduced and production cost is lowered.

Description

technical field [0001] The invention belongs to the technical field of organic chemical synthesis, and in particular relates to a method for improving the purity of N,N'-dicyclohexylcarbodiimide products. Background technique [0002] N,N'-dicyclohexylcarbodiimide (DCC) is a good low-temperature biochemical dehydrating agent, used for the synthesis and dehydration of amikacin and amino acids, and also for the dehydration of acids, anhydrides, aldehydes, ketones, etc. Synthesis, this product is also used in the synthesis of peptides and nucleic acids. DCC dehydration condensation is used, the reaction conditions are mild, and the synthesis yield is high, so it is often used as a dehydrating agent or carboxyl activator for polypeptide synthesis, or for coupling small molecular compounds and polypeptides with carrier proteins. In the 1980s, biological peptide condensing agents began to be synthesized and applied to the experimental research of peptides. Due to its complex synt...

AI Technical Summary

Problems solved by technology

[0006] 1. Dehydration of DCU to prepare DCC needs to be carried out under anhydrous conditions, which is not easy to control;

[0007] 2. The use of highly corrosive p-toluenesulfonyl chloride, benzenesulfonyl chloride, phosphorus pentoxide, etc. requires harsh reaction conditions, so it is only suitable for a small amount of preparation in the laboratory;

[0009] 4. The product yield is only 65% ​​(calculated by cyclohexylamine); the purity is about 98%

[0012] 1. The yield of the solvent-based thiourea synthesis process is low and the pollution is large;

[0013] 2. The one-step conversion rate of sodium hypochlorite oxidation is low, and the yield is only 70%;

[0014] 3. A small amount of sulfur in the oxidizing solution is difficult to remove. When rectifying at high temperature (above 200°C), the product will decompose, and the resulting product will turn yellow in appearance, with a purity of only 98%;

[0016] 5. The distillation head and tail contain impurities, which cannot be directly processed to pass