Patent ID: 6398922
Filing Date: 2002-06-04
Classification: B01J,C07C

Abstract:
A process for halogenating alkylbenzenes in an axially symmetrical photochemical gas/liquid reactor, wherein said reactor comprises:a vessel; a central radiation source; at least one gas distributor at the bottom of said reactor; and an inner sleeve means arranged concentrically between the radiation source and the vessel, said inner sleeve means comprising slots along at least a part of its length, said inner sleeve means allowing internal recirculation of reaction liquid, said recirculation comprising a rising movement of the liquid in the space situated between the radiation source and the inner sleeve means and a descending movement in the space situated between the vessel and the inner sleeve means, said process comprising: introducing a liquid phase comprising an alkylbenzene into the vessel and a gas phase comprising a halogen into the gas distributor; recirculating the reaction liquid within the vessel; and calibrating the size of the slots to enable recirculation to be printed and maintained regardless of the level to which the reactor is filled; whereby a reaction product is formed which is substantially free of derivatives of alkylbenzene that are halogenated on the aromatic ring.