Although phase-transfer catalysis usually enables the advantage of avoiding the use of water-miscible polar aprotic solvents that make workup and handling losses a problem, sometimes it is preferable to combine PTC with the strengths of a polar aprotic solvent.
The patent shown in the diagram (published this week) uses PTC with polar aprotic solvents like acetonitrile (Example 1) and DMF (Example 3). The inventors likely used PTC with acetonitrile or DMF because the starting materials or products are very polar, likely so polar that they don’t dissolve well in non-polar solvents. So, instead of choosing between PTC and polar solvent, the inventors get the benefits of both.
In this reaction with chloroacetonitrile and ring closure, they use the product as the intermediate in the next step without further purification, so the use of acetonitrile streamlines the process for the next step.
One reason that phase-transfer catalysis excels in streamlining processes is that you can choose almost any solvent you want for PTC applications since quats or complexants can transfer almost any anion into almost any organic liquid where it can react with enhanced reactivity.
If your company wants to streamline processes to achieve low-cost high-performance green chemistry, contact Dr. Marc Halpern of PTC Organics to explore integrating highly specialized expertise in industrial phase-transfer catalysis with your commercial goals and additionally benefit from higher 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!).
