catalyst molar ratio is between about 30 000 1 and 50 000 1 the amounts of catalyst and co catalyst are typically sufficient to provide a molar ratio of catalyst co catalyst of between about 0 01 1 and 20 1 preferably between about 0 0 1 and 10 1 although it is preferred to carry out the process at atmospheric pressure sub atmospheric or superatmospheric pressures may be employed if desired under atmospheric pressure the chlorination of alkylbenzenes in accordance with the present invention may be carried out over a wide range of temperatures ranging for example from sub zero temperatures such as 30 u00b0 c or below to over 100 u00b0 c the upper limit of temperature is of course determined by the boiling point of the reaction medium and may depending on the boiling point limitation range as high as 150 u00b0 c or higher however no practical advantage is gained through the use of higher temperatures or extremely low temperatures and it is preferred to employ temperatures in the range of about 20 u00b0 to 100 u00b0 c and preferably about 40 u00b0 to 60 u00b0 c the optimum temperature will vary somewhat depending on the particular alkylbenzene and catalyst system employed the following specific examples are provided to further illustrate this invention and the manner in which it may be practiced in a glass reactor wrapped in aluminum foil a mixture of 70 4 g 0 764 mole of toluene 0 0062 g 3 8 u00d7 10 5 mole fecl 3 and 0 0045 g 1 911 u00d7 10 5 mole of 2 3 dihydro 2 3 tetramethylene 1 5 benzo 1.