Patent ID: 6011185
Filing Date: 2000-01-04
Classification: C07C

Abstract:
A process of producing HFC-125 comprising the steps of:(1-ii-a) reacting PCE and HF in the presence of catalyst at a reaction temperature in the range between 60.degree. C. and 150.degree. C. in a liquid phase first reaction step so as to obtain a first reaction mixture comprising HCFC-123 and/or HCFC-122,(1-ii-b) obtaining a first fraction from the first reaction mixture which fraction comprises HCFC-123 and/or HCFC-122 and HCl and a portion of unreacted HF,(1-ii-c) obtaining a fifth fraction by removing HCl from the first fraction which contains HCl,(1-ii-d) reacting the fifth fraction, optionally with additional HF, in the presence of catalyst at a reaction temperature in the range between 250.degree. C. and 450.degree. C. in a vapor phase second reaction step so as to obtain a second reaction mixture comprising HCFC-123, HCFC-124, HFC-125, HCl and HF,(1-ii-e) separating the second reaction mixture into three fractions: a second fraction which comprises most of HCFC-123 and/or HCFC-124 of the second reaction mixture and HF entrained therewith, a third fraction which comprises most of HFC-125 and HCl of the second reaction mixture, and a fourth fraction which comprises the rest of HF,(1-ii-f) recirculating the second fraction to the step (1-ii-d) and reacting it together there,(1-ii-g) recirculating the fourth fraction to the step (1-ii-a) and/or the step (1-ii-d) and reacting it together there, and(1-ii-h) separating out HFC-125 from the third fraction.