Imperial Chemical Industries Limited

Robert W Wheelhouse

David G Hey

Andrew M Taylor

A method for separating HFA 134a from an HFA 134a-rich mixture thereof with HF and/or CFC 1122 which comprises feeding the mixture to a distillation column to separate an azeotrope or near-azeotrope of HFA 134a and HF and/or CFC 1122 from a residue comprising substantially pure HFA 134a. Starting from an HF-rich mixture of HFA 134a such as a typical product stream in HFA 134a production, the method includes a first distillation step to separate HF from the initial mixture and produce an azeotrope or near azeotrope of HFA 134a and HF which is an HFA 134a-rich mixture.

Process for separating HFA 134a

A composition for cleaning printed circuit boards contains 92 to 95 weight percent 1,1,2-trichloro-1,2,2-trifluoroethane, 5 to 7 weight percent methanol and 0.05 to 1 weight percent methyl acetate.

Cleaning composition

A composition suitable for cleaning printed circuit boards consists of 89.5% to 96.9% 1,1,2-trichloro-1,2,2-trifluoroethane, 2.5% to 8% ethanol, 0.1% to 3% methyl acetate and preferably 0.01% to 0.5% nitromethane.

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Runcorn, United Kingdom

Robert W Wheelhouse