a polyester as is known is prepared by the reaction between a dicarboxylic acid and a polyol e g a glycol examples of conventional dicarboxylic acids suited for manufacturing polyester polyols include succinic glutaric adipic sebacic phthallic terephthallic maleic fumaric itaconic citraconic and the like glycols include ethylene glycol propylene glycol and butylene glycol in the preparation of polyurethanes conventional additives can be utilized for their desired effect without departing or detracting from the advantageous aspects of the catalysts of this invention for example blowing agents such as water or a volatile organic such as dichlorodifluoromethane dichlorofluoromethane trichloromonofluoromethane dichlorofluoromethane difluorodichoroethane methylene chloride carbontetrachloride butane pentane and the like foam stabilizers or surfactants are other additives which can be added for enhancing the retention of gas generated during the polymerization reaction and such stabilizers include silicone block polymers comprising polyalkylene glycol units n vinyl pyrrolidone or n vinyl pyrrolidone dibutyl maleic copolymers or n vinyl pyrrolidone dibutyl maleate vinyl acetate other examples are shown in u s pat no 3 746 663 in preparing the polyurethanes the amine salt of a mannich acid adduct is added to the urethane composition in at least a sufficient or effective proportion for enhancing the cure rate of the urethane when the catalyst is.