Trihexyl tetradecyl phosphonium chloride is a highly organophilic quat with a C# of 32 and modified q-value of 0.57 beyond the looseness of the ion pair due to the large polarizable phosphorous atom bearing the positive charge.
US Patent 8,920,673 shows how liquid-liquid ion exchange can be used to replace chloride in trihexyl tetradecyl phosphonium chloride with various carboxylates, phenoxides and other organic anions with just one extraction. These materials are used as room temperature ionic liquids.
Typically liquid-liquid ion exchange to replace chloride or bromide in quats is performed by multiple extractions or countercurrent extraction. When the anions replacing chloride are organophilic enough, their affinities for the organophilic quat are strong enough be effectively displace the chloride anion in just one extraction.
As we teach in the 2-day PTC course “Industrial Phase-Transfer Catalysis,” the relative affinities of various anions for quats is often important to optimize commercial PTC processes.
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!).
