The Industrial Phase-Transfer Catalysis Experts

PTC Tip of the Month E-Newsletter

PTC Tip of the Month - November 2023

18-Crown-6 with Potassium Peroxide

By Marc Halpern, the leading expert in industrial phase-transfer catalysis.

The second reaction shown in the diagram uses crown ether presumably to transfer potassium peroxide to the organic phase by complexation. The crown ether is not catalytic and is used in large quantities, apparently to match the large loading of the potassium peroxide.

In the first step, the alcohol is converted into the mesylate. In the second step, the peroxide appears to attack the mesylate by a nucleophilic substitution based on the inversion of configuration. At the same the, the acetate is hydrolyzed to the alcohol (obviously with retention of configuration).

We would be curious to learn if our readers have encountered using peroxide as a nucleophile in this manner.

About Marc Halpern

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!).

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