PURPOSE: To inhibit corrosion of a vacuum device by using an aqueous solution of sodium hydroxide as a cooling solution of the vacuum device installed at a hydrogen chloride-recovering process in producing the subject compound from phenol and acetone using hydrogen chloride as a catalyst.

CONSTITUTION: Bisphenol A is produced by reacting phenol with acetone using hydrogen chloride as a catalyst. In said process, an aqueous solution of sodium hydroxide is used as a cooling solution of a vacuum device, e.g., a barometric condenser supplied from a line 11, installed at a process recovering hydrogen chloride in said producing process to wash gas containing hydrogen chloride in a line 7, and corrosion of said vacuum device is inhibited, then a stable operation of said production process is able to be performed and, simultaneously, a problem in an environmental health is resolved by completely removing hydrogen chloride gas in waste gas 12.