Dehydrochlorination of a dihydroxydiphenyl trichloroethane

In a process for dehydrohalogenating the trichloride, 1,1,1-trichloro-2,2-bis-(4-hydroxyphenyl) ethane, to form the dichloride of the formula ##STR4## which process comprises (1) treating the aforesaid trichloride with liquid methyl amine in an amount sufficient to act as both a dehydrohalogenating agent and solvent, the improvement comprising the said methyl amine in combination with an amount of a salt effective to accelerate the dehydrohalogenation reaction, wherein said salt is selected from the class consisting of methyl amine hydrochloride and hydrobromide, ethyl amine hydrochloride and hydrobromide, dimethyl amine hydrochloride and hydrobromide, ammonium chloride and bromide, lithium chloride and bromide, and sodium chloride and bromide, to form a substantially pure dichloride of the above formula, and (2) removing the unreacted methyl amine and salt thereby isolating the desired dichloride, the said salt being used in an amount ranging from 0.5 to 20%, by weight, based on the weight of the methyl amine.