Procedure for the photochlorination of alkyl-aromatic compounds

A process for the selective photochlorination of the side chain of an alkyl-aromatic compound by contact with chlorine under action of light radiation comprising:

• 1) continuously removing a portion of an alkyl-aromatic compound from a container;
• 2) mixing said alkyl-aromatic compound with chlorine in a static mixer to obtain a homogeneous mixture;
• 3) feeding said homogenous mixture, in the liquid phase, to the bottom of a long-tubular-shaped reactor, without any mechanical stirring, said reactor being at least partially composed of a material which is transparent to light radiation and externally equipped with a supply of light radiation, said reactor being maintained under photochlorination conditions;
• 4) reacting said homogenous mixture to almost completely use up said chlorine;
• and
• 5) recovering a reaction mixture of a chlorinated alkyl-aromatic compound and hydrochloric acid by-product, at the head of said reactor,
• wherein said reaction mixture is continuously cycled to said container, where a gaseous hydrochloric acid is separated from said chlorinated alkyl-aromatic compound, and
• wherein said alkyl-aromatic compound is partially chlorinated at each cycling in said reactor, the number of cycles depending on the degree of chlorination desired.