Imperial Chemical Industries Limited

Ineos Fluor Holdings Limited

Ineca Fluor Holdings Limited

Charles John Shields

Paul Nicholas Ewing

John David Scott

Christopher Roberts

Robert E Low

Richard Llewellyn Powell

Barry William Farrant

David William Bonniface

Gary Goodyear

Pravin K Dattani

Adrian S Swindells

A process for separating and recovering hydrogen fluoride from a mixture with an organic compound especially a fluorine-containing compound by extraction with a solution of an alkali metal fluoride in hydrogen fluoride, phase separation and recovery. A process for producing a fluorine-containing organic compound by fluorinating a starting material with hydrogen fluoride and similarly recovering hydrogen fluoride from the product stream. The solution may be anhydrous or aqueous.

Hydrogen fluoride recovery process

Processes for separating and recovering hydrogen fluoride from a gaseous mixture of an organic compound and hydrogen fluoride are disclosed. The processes include contacting the gaseous mixture with a solution of an alkali metal fluoride in hydrogen fluoride, separating a gas phase depleted in hydrogen fluoride and containing the organic compound from a liquid phase, and recovering hydrogen fluoride from the liquid phase.

A process for the removal of chloroalkane, chlorofluoroalkane and/or hydrofluoroalkane impurities from pentafluoroethane which comprises contacting the impure pentafluoroethane with hydrogen at elevated temperature in the presence of a hydrogenation catalyst to convert the impurity or impurities to a hydrofluoroalkane and/or a hydrocarbon and separating the resulting hydrofluoroalkane and/or hydrocarbon from the pentafluoroethane.

Purification of pentafluoroethane

A process for the production of pentafluoroethane which comprises the steps (i) producing a composition comprising a compound of formula C.sub.2 HCl.sub.x F.sub.y in which x=1,2 or 3 and y=2,3 or 4 provided that x+y is 5, contaminated with a compound of formula C.sub.2 Cl.sub.x+1 F.sub.y, (ii) separating the compound of formula C.sub.2 HCl.sub.x F.sub.y from the compound of formula C.sub.2 Cl.sub.x+1 F.sub.y, and (iii) contacting the compound of formula C.sub.2 HCl.sub.x F.sub.y with hydrogen fluoride in the presence of a fluorination catalyst to produce pentafluoroethane is disclosed.

Production of pentafluoroethane

A process for the removal of 1,1,2,2-tetrafluoroethane from 1,1,1,2-tetrafluoroethane which comprises contacting 1,1,1,2-tetrafluoroethane containing 1,1,2,2-tetrafluoroethane with a zeolite having a mean pore size in the range of 3.8 .ANG. an 4.8 .ANG.. The zeolite is preferably calcium chabazite.

Purification of 1,1,1,2-tetrafluoroethane

Process for the manufacture of pentafluoroethane

A process for the co-production of two or more hydrofluoroalkanes which comprises contacting an alkene or a halogenated alkane with hydrogen fluoride at elevated temperature in the presence of a fluorination catalyst to produce a first hydrofluoroalkane and wherein an organic precursor to a second hydrofluoroalkane is provided in the process whereby to produce a second hydrofluoroalkane in addition to the first hydrofluoroalkane. In particularly preferred embodiments of the process, the first hydrofluoroalkane is 1,1,1,2-tetrafluoroethane derived from 1-chloro-2,2,2-trifluoroethane or trichloroethylene and the second hydrofluoroalkane is one or more of pentafluoroethane, difluoromethane and 1,1,2,2-tetrafluoroethane.

Production of hydrofluoroalkanes

A process for the removal of 1-chloro-2,2-difluoroethylene from 1,1,1,2-tetrafluoroethane by contacting the mixture with a zeolite having a mean pore size in the range of 3.5 .ANG. and 4.8 .ANG. and having potassium as counter cation. The zeolite having potassium as counter-cation may be produced by cation-exchange with a commercially available zeolite, for example AW-500.

Method for separating 1,1,1,2-tetrafluoroethane from a mixture thereof with chlorine-containing halogenated hydrocarbons such as HCFC's 1122, 124, 114, 114a and 133a which comprises adding an extraction agent to the mixture and extractively distilling the mixture in an extractive distillation zone from which HFA 134a containing less than 10 ppm of chlorinated contaminants is recovered. Suitable extraction agents include trichloroethylene, perchloroethylene, alpha-pinene and cyclohexane.

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Warrington, United Kingdom

Charles John Shields