Elf Atochem S.a.

Atofina

Christophe Ruppin

Gilles Drivon

Jean-Philippe Gillet

David Reeves

Didier Faure

Philippe Corbiere

Alain Wattier

The invention relates to a method for preparing bromodifluoroacetic compounds which comprises converting a 1,1-difluoro-1,2-dibromodihaloethane with oleum having 50-70% SOto a bromodifluoroacetyl halide (bromide or chloride) and then in reacting the latter directly with either an alcohol, or with water.

Method for preparing bromodifluoroacetic compounds

The invention relates to a continuous process for the preparation of pivaloyl chloride and of aroyl chloride, in particular of benzoyl chloride, which consists in reacting pivalic acid with a trichloromethylated aromatic compound in the presence of a catalyst at a temperature of between 60&deg; C. and 180&deg; C. under reduced pressure. The products formed are continuously removed from the reaction region, the hydrogen chloride formed being treated in a washing region in which a trichloromethylated compound moves countercurrentwise.

Continuous process for the preparation of pivaloyl chloride and of aroyl chloride

For preparing bis-silyl carboxamides in a semi-continuous, reacting an amide or the N-trimethylsilyl derivative thereof with a silylating agent and, at the same time, extracting the bis-silyl carboxamide formed by distillation under reduced pressure.

Semi-continuous process for preparing bis-silyl carboxamides

The invention relates to a process for manufacturing bis-silyl ureas which consists in reacting urea and a disilazane in an aliphatic nitrile and most particularly in acetonitrile. The process of the present invention applies particularly to the manufacture of bis(trimethylsilyl)urea from urea and hexamethyldisilazane.

Process for manufacturing bis-silyl ureas

Method for preparing .alpha.,.omega.-bromochloroalkanes

Method for preparing .alpha., .omega.-bromochloroalkanes

A process for the preparation of alkyl halodifluoroacetates comprises reacting a 1,1-difluorotetrahaloethane with an alcohol, e.g., ethanol or isopropanol, in the presence of oxygen and a chemical free-radical initiator, e.g., an azo compound.

Process for the preparation of alkyl halodifluoroacetates

A process for the preparation of 3-chloropropionic acid consists especially in simultaneously introducing hydrochloric acid gas and acrylic acid at a molar ratio of 0.7:1 to 1.3:1 into a sediment consisting of 3-chloropropionic acid optionally diluted with water or with an aqueous hydrochloric acid solution.

Process for the preparation of 3-chloropropionic acid

For the preparation of alkyl halodifluoroacetates, a 1,1-difluorotetrahaloethane is reacted with an alcohol in the presence of air and/or oxygen and a free-radical initiator, such as for example an azo compound, e.g., azobis(isobutyronitrile).

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Pierre Benite, France

Christophe Ruppin