We all know that cesium salts are very expensive. Cesium salts are used when you need better solubility in polar organic solvent s than potassium salts and looser ion pairs than potassium salts.
What can be even better than cesium salts for organic solubility and even looser than cesium salts for higher reactivity? Tetrabutylammonium salts of course!
US Patent 9,493,415 issued this month and demonstrates that tetrabutylammonium chloride is the most effective tetrabutylammonium salt that enables the use of potassium fluoride to replace the use of cesium fluoride.
However, the quantities of TBAC are large from 50mole% as a catalyst (71% yield) to 2.0 equiv TBAC (86% yield). The inventors tried a few more stable phase-transfer catalysts such as tetraphenylphosphonium chloride, 18-crown-6 and tetramethylammonium chloride but they did not outperform tetrabutylammonium chloride.
We can think of a variety of other more stable phase-transfer catalysts that should have been tried but were not reported in the patent.
If your company wants to develop the most cost effective PTC process, now contact Marc Halpern of PTC Organics Inc. to explore collaboration by integrating the highly specialized expertise of PTC Organics with your company’s commercial goals for increased profit and process performance.
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!).
