Continuous Process for the Preparation of Pivaloyl Chloride and of Aroyl Chloride 

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

US 6605743 B1

ABSTRACT

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° C. and 180° 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.

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CLAIMS(18)

What is claimed is:

1. A continuous process for the preparation of pivaloyl chloride and of aroyl chloride (2) by reaction of pivalic-acid with a trichloromethylated aromatic compound (1) according to the reaction:

in which R represents a halogen atom, a linear or branched alkyl radical having a carbon number of 1 to 4, a linear or branched perfluoroalkyl radical having a carbon number of 1 to 4 or a —COCl radical, m=0, 1 or 2 and n=1, 2 or 3 and in which the —CCl3 groups are situated on non-adjacent carbon atoms when n>1, in the presence of at least one Friedel-Crafts catalyst, said process comprising

simultaneously and continuously introducing pivalic acid, at least one trichloromethylated aromatic compound (1) and at least one Friedel-Crafts catalyst into a reactor and reacting with stirring and under reduced pressure at a temperature of 60° C. to 180° C.,

continuously separating unconverted reactants from products formed in gas flow exiting at the top of the reaction region,

partially condensing the products formed into a liquid mixture comprising pivaloyl chloride and aroyl chloride (2),

treating, in a washing region in which a trichloromethylated aromatic compound (1) moves countercurrentwise, remaining uncondensed gaseous mixture comprising hydrogen chloride, and...