PTC was used for 2-step 1-pot reactions of etherification between various fluorous compounds followed by dehydrofluorination.
Aqueous KOH was used as base to deprotonate 1.0 equivalent of trifluoroethanol and react with 1.0 equivalent of CF₃CFHCFHCF₂CF₃ to form the ethers at the 2-position and 3-position (~3:1 ratio). Excess base then dehydrofluorinated these compounds to form the enol ethers.
The total reaction time was about 7.5 hours, including a 30 minute dropwise addition of the decafluoropentane at 5-10 deg C. Most of the reaction after the addition was performed at ambient temperature.
It is not known if the bromide from the 1.2 mole% tetrabutylammonium bromide acted as a co-catalyst at these relatively low temperatures.
It is possible that the low temperature was chosen to avoid premature dehydrofluorination prior to etherification.
The reason for the yield loss is not specified though it could be choosing the fraction from the Vigreux column distillation.
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!).
