A process for producing a bisphenol compound useful as deterioration preventor capable of stabilizing organic substances against the decompositions caused by heat, light and oxygen, represented by the following general formula: ##STR1## wherein R.sub.1 represents alkyl group having 1 to 3 carbon atoms, alkenyl group having 2 to 4 carbon atoms, phenyl group or 2-phenylethenyl group; R.sub.2 represents alkyl group having 1 to 5 carbon atoms, or cyclohexyl group; R.sub.3 represents alkyl group having 1 to 9 carbon atoms, cyclohexyl group or phenyl group; and R.sub.4 represents alkyl group having 1 to 11 carbon atoms or phenyl group, which comprises reacting a carboxylic acid represented by the following general formula: ##STR2## wherein R.sub.1 is as defined above, with a bisphenol compound represented by the following general formula: ##STR3## wherein R.sub.2, R.sub.3 and R.sub.4 are as defined above, by the use of a halogenating agent in the presence of a dehydrohalogenating agent, as well as butadiene polymer compositions containing said bisphenol compounds.