When a PTC reaction works so well that multiple phase-transfer catalysts work very well (and non-PTC processes give much lower yield or selectivity), then one can use the least expensive phase-transfer catalyst.
In this case of N-mesylation, tetramethyl ammonium chloride worked about as well as TBAB and benzyl triethyl ammonium chloride, so 1/3 the weight of the less expensive TMAC was used instead of the standard TBAB. Less weight plus less cost per weight results in more savings.
It is interesting to note that mono-N-mesylation is achieved in high yield and selectivity. One may speculate that if base would have been used, di-N-mesylation may have been observed since the mono-N-mesylated aniline is more acidic than the non-mesylated aniline.
Your PTC process development program can benefit from expert choice of phase-transfer catalyst for reactivity, selectivity, catalyst separation from the product and catalyst cost. Now contact Marc Halpern of PTC Organics to learn how to optimize choice of phase-transfer catalyst.
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!).
