Dr. Neal Anderson of Anderson’s Process Solutions, has been a loyal reader and contributor to the PTC Tip of the Month for more than two decades. Dr. Anderson suggested an alternative explanation for the reaction mechanism for the condensation reactions reported last month shown here: http://phasetransfercatalysis.com/ptc_tip/omission-from-condensation-procedure-or-no-ptc-2/.
Dr. Anderson explains: “Technically the reaction in the patent is HCl elimination and two Claisen condensations, or 2 aldol reactions + dehydration. They can be catalyzed by acid or base, usually base. The diethylaniline is a weak base. Reaction with an aldehyde carbonyl are similar to a Knoevenagel reaction, which are are acid-catalyzed. I suspect that TBAB is generating HBr as a useful co-catalyst.”
The PTC community thanks Dr. Anderson for his continued contributions to the process chemistry community in general and the PTC community in particular. Please visit Dr. Anderson’s website for useful process development tips, consulting and training services.
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!).
