of methyl mercaptan was added 15 minutes after the beginning of bubbling the phosgene in place of adding 0 48 g 0 015 m of methanol after the beginning of bubbling the phosgene the result is shown in table 4 repeating the procedure of example 20 except that 0 70 g 0 005 m of benzoyl chloride was added in place of adding 0 48 g 0 015 m of methanol the result is shown in table 4 table 4__________________________________________________________________________ example 21 22 23__________________________________________________________________________monohydric type p t butylphenol p t butylphenol p t butylphenolphenols mole based on bisphenol a 3 3 3 type methanol methyl mercaptan benzoyl chloride time of addition before bubbling at 15 minutes after bubblingchain terminator phosgene after the phosgene beginning of bubbling phosgene mole based on bisphenol a 20 3 1 before the reaction polycarbonate prepolymer 0 098 0 382 0 415intrinsic after the after meltingviscosity reaction for 30 minutes 0 264 0 549 0 522 u03b7 product of the melting polyconden after melting 0 450 0 716 0 593 sation for one hour reaction __________________________________________________________________________ to 55 g 1 37 m of sodium hydroxide dissolved in 660 ml of distilled water were added 300 ml of methylene chloride 2 25 g 0 015 m of p t butylphenol 114 g 0 5 m of bisphenol a the resulting mixture.