METHOD OF DIFLUOROCHLOROMETHANE SYNTHESIS Russian patent published in 1994 - IPC

FIELD: chemical technology of organic compounds. SUBSTANCE: synthesis is carried out at 70-100 C by reaction of CHCl₃ with HF in the presence of SbCl₅ following by direct two-stage rectification at 18-30 C in the first column under pressure 9.8-12 atm, and at 30-90 C and 8-11 atm in the second column. HCl and CHF₃ are removed from the top of the first column. In the second column the process is carried out in the presence of CHCl₃ and SbCl₅ at the concentration in vat fluid 22.9-57.1% and 3-30.8% foe 0.5-1 h, and light fraction CHF₂Cl is isolated. Under these conditions purity of abgas HCl is increased (from 0.3 to 0.01% by HF content), and the yield of CHF₂Cl is increased up to 99.2% . By-side processes of hydrofluoric acid production are excluded. EFFECT: enhanced yield of the end product, simplified technological process. 4 tbl