Method for preparation of high purity and high yield metformin hydrochloride by two-component solvent

• Main Authors: WANG CUI, LI FANG, GUO XUEYANG, YANG RONGHUA, GUO XIANGRONG
• Format: Patent
• Language: English
• Published: 12.08.2015
• Subjects: ACYCLIC OR CARBOCYCLIC COMPOUNDS; CHEMISTRY; METALLURGY; ORGANIC CHEMISTRY

The invention discloses a method for preparation of high purity and high yield metformin hydrochloride by a two-component solvent. The method includes: preparation of dimethylamine hydrochloride and preparation of metformin hydrochloride. During preparation of dimethylamine hydrochloride, dimethylamine gas and 31% hydrochloric acid are adopted as the raw materials to carry out reaction, through co-cooling of a cooler and a reaction kettle jacket, pumping circulating, spraying absorption of dimethylamine tail gas and absorption of dimethylamine tail gas by hydrochloric acid, the utilization rate of the raw materials is maximumly ensured, the loss of raw materials is reduced, and the product yield is improved. During preparation of metformin hydrochloride, dimethylformamide and ethylene glycol monopropyl ether two components are used as the solvent, the synergistic effect of the two solvents with different natures are utilized, and the prepared metformin hydrochloride product has yield of over 95% and purity of more than 99.90%.