- Preparation of carboxylic acids
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Carboxylic acids can be prepared by reacting compounds comprising a -CCl 2 F group, a CCIF 2 group or a CCl 3 group with sulfur trioxide and sulfuric acid. The reaction is especially suitable for the preparation of 3,3,3-trifluoropropionic acid from CF 3 -CH 2 -CCl 2 F, CF 3 -CH 2 -CCIF 2 , CF 3 -CH 2 -CCl 3 or a mixture of one or two thereof as starting material. Usually, oleum is used as the source for sulfur trioxide. In a preferred embodiment, the starting material comprises CF 3 -CH 2 -CCl 2 F and/or CF 3 -CH 2 -CCIF 2 which is or are prepared in a fluorination reaction between CCl 3 -CH 2 -CCl 3 and HF. As a source for CCl 3 -CH 2 -CCl 2 , the product of the reaction between CH 2 =CCl 2 and CCl 4 is advantageously used.
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Page/Page column 3-4
(2008/06/13)
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