The synthesis of 1,1-BIS(4-HYDROXYPHENYL)-3,3,5-TRIMETHYLCYCLOHEXANE is as follows:112.8 g (1.2 mol) of phenol, 16.9 g of water, 0.5 g of 75% aqueous solution of phosphoric acid and 7.2 g of BPTMCP crystals were placed in a one liter capacity four-necked flask provided with a thermometer, a dropping funnel, a reflux condenser and a stirrer to prepare a slurry. The slurry was adjusted at a temperature of 20° C. After the inside the flask was replaced by nitrogen gas, hydrogen chloride gas was introduced into the flask under stirring. The gas composition in the reaction vessel was analyzed and the volume concentration of hydrogen chloride gas was adjusted at 80%. 4.2 g of 15% aqueous solution of sodium methyl mercaptide was added dropwise to the slurry while the slurry was maintained at a temperature of 20° C., and then a mixture of 112.8 g (1.2 mol) of phenol and 42.0 g (0.3 mol) of TMC was added dropwise to the slurry over a period of six hours. The reaction mixture was found to increase in temperature during the addition, and when the addition was completed, the temperature was found to be 40° C. Then, the reaction was further continued at a temperature of 40° C. for anther three hours under stirring until completion. The reaction mixture was found to be slurry throughout the reaction from the start of the reaction when the mixture of phenol and TMC was added dropwise to the slurry to the completion of the reaction. The resulting reaction mixture was analyzed by liquid chromatography. The production yield (mol of BPTMC produced/mol of starting TMC used) was found 92.9%.
