In November, there were at least two examples of quats being used as curing catalysts in polymerizations.
In US 12,460,051, quaternary ammonium hydroxides and acetates were employed as moisture-cure catalysts for silicone-based sealants. These salts, including tetrabutylammonium hydroxide, activate silanol condensation without the use of tin or titanium, metals that raise toxicity and environmental flags. Although there’s no phase-transfer catalysis here, the quat salts provide strong base activity, excellent dispersion in organic polymers and a favorable regulatory profile.
In US Patent Application Publication 2025/0353959, tetrabutylammonium acetate was used in polyurethane curing, not for ion transfer or deprotonation, but to improve the properties of the final product. This quat salt catalyzes the isocyanate-polyol reaction with minimal yellowing, outperforming conventional tertiary amine and organotin catalysts in producing low-color, high-transparency polyurethanes. The acetate counterion appears to contribute to reactivity, selectivity and material appearance.
About Marc Halpern
Dr. Halpern is founder and president of PTC Organics, Inc., the only company dedicated exclusively to developing low-cost high-performance green chemistry processes for the manufacture of organic chemicals using Phase Transfer Catalysis. Dr. Halpern has innovated PTC breakthroughs for pharmaceuticals, agrochemicals, petrochemicals, monomers, polymers, flavors & fragrances, dyes & pigments and solvents. Dr. Halpern has provided PTC services on-site at more than 260 industrial process R&D departments in 37 countries and has helped chemical companies save > $200 million. Dr. Halpern co-authored five books including the best-selling “Phase-Transfer Catalysis: Fundamentals, Applications and Industrial Perspectives” and has presented the 2-day course “Practical Phase-Transfer Catalysis” at 50 locations in the US, Europe and Asia.
Dr. Halpern founded the journal “Industrial Phase-Transfer Catalysis” and “The PTC Tip of the Month” enjoyed by 2,100 qualified subscribers, now beyond 130 issues. In 2014, Dr. Halpern is celebrating his 30th year in the chemical industry, including serving as a process chemist at Dow Chemical, a supervisor of process chemistry at ICI, Director of R&D at Sybron Chemicals and founder and president of PTC Organics Inc. (15 years) and PTC Communications Inc. (20 years). Dr. Halpern also co-founded PTC Interface Inc. in 1989 and PTC Value Recovery Inc. in 1999. His academic breakthroughs include the PTC pKa Guidelines, the q-value for quat accessibility and he has achieved industrial PTC breakthroughs for a dozen strong base reactions as well as esterifications, transesterifications, epoxidations and chloromethylations plus contributed to more than 100 other industrial PTC process development projects.
Dr. Halpern has dedicated his adult life to his family and to phase-transfer catalysis (in that order!).
