A patent that issued yesterday describes the formation of an aryl glycidyl ether with 3 consecutive PTC steps in one pot.
In the first step, the bromide from tetraethylammonium bromide attacks epichlorohydrin to form bromochloropropanol intermediate (presumably in a low steady state concentration). Base is used to deprotonate the benzophenone phenol that is transferred to the reaction phase by the tetraethylammonium quat that reacts with the bromochloropropanol to form a halohydrin. The third step is a phase-transfer catalyzed intramolecular etherification of the halohydrin.
For those of you who have taken our course “Industrial Phase-Transfer Catalysis”, you recognize that all three reactions are likely I-reactions which suggests that tetraethylammonium is far from an optimal structure for I-reactions. It is possible that the tetraethylammonium is decomposing at the high temperature and in the presence of base after the base is added, then requaterizing with epichlorohydrin (used in excess) to regenerate a quat that is effective as a phase-transfer catalyst.
If your company seeks to develop low-cost high-performance green chemistry for base-promoted reactions and/or nucleophilic substitutions, now contact Marc Halpern of PTC Organics to integrate highly specialized expertise in industrial phase-transfer catalysis with your commercial process development, process improvement or process retrofit programs to increase profit and process R&D efficiency.
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!).
