GB723592A - Process for producing meta-dichlorobenzene - Google Patents

Abstract

A process for producing meta-dichlorobenzene isomerically from o-dichlorobenzene, or p-dichlorobenzene or a mixture of dichlorobenzenes containing less than 55 per cent by weight of m-dichlorobenzene comprises heating such dichlorobenzene or mixture of dichlorobenzenes under substantially anhydrous conditions to a temperature above the respective normal boiling point and at a superatmospheric pressure in the presence of at least 1 part by weight of anhydrous aluminium chloride per 100 parts by weight of the dichlorobenzene or mixture of dichlorobenzenes. In a modified process water is present in an amount not in excess of 10 per cent by weight based on the weight of the anhydrous aluminium chloride. In examples: a mixture of o, m and p-dichlorobenzenes is obtained by heating o-dichlorobenzene containing minor amounts of the other isomers in a seated tube with aluminium chloride, adding water to hydrolyse the latter and steam distilling the product (1); p-dichlorobenzene is employed as starting material in a similar process (2); similar processes are carried out using various amounts of aluminium chloride (3) and various temperatures (4), whilst (4) is repeated using p-dichlorobenzene as starting material (5). For comparison other runs are carried out at lower temperatures. Specification 699,153 is referred to.