Abstract: Per(poly)fluorinated polyoxyethylated carbamates of general formula (I) in which R.sub.F represents a perfluorinated group containing between 1 and 18 carbon atoms, W represents an oxo group or nothing, n is an integer from 1 to 10, m is from values 2 to 6, 80 or not defined, R is an alkyl group, R.sub.F W(CH.sub.2).sub.n+1 NHC(O)-- in which R.sub.F and W are as defined above, --(CHCH.sub.3 CH.sub.2 O).sub.30 (CH.sub.2 CH.sub.2).sub.80 C(O)NH(CH.sub.2).sub.n+1 R.sub.F in which R.sub.F is a perfluorinated group containing from 1 to 18 carbon atoms, R' is a hydrogen atom, an alkyl group containing between 1 and 18 carbon atoms which is optionally substituted, an optionally substituted aryl or aralkyl group, an allyl, methallyl or propargyl group or a perfluorinated chain having between 1 and 18 carbon atoms.

Abstract: 1,1,1.Trifluoro-2-fluoroethane (HFC 134A), respectively 1,1,1-trifluoro-2, 2-dichloroethane (HCFC 123) 1,1,1-trifluoro-2-chloro, 2-fluoroethane (HCFC 124) and pentafluoroethane (HFC 125), are purified from impurities respectively consisting of 1,1-difluoro-2-chloroethylene (HCFC 1122) and of difluorodichloroethylene (CFC 1112A and CFC 1112), by reacting in the liquid state respectively HFC 134A or HCFC 123, HCFC 124 and HFC 125 containing the relative impurities, with elemental fluorine, at temperatures ranging from -80.degree. to -40.degree. C.