Several thousand US patents issued in the past couple of weeks including US Patent 9,000,000 marking another million patent threshold.
Out of curiosity, we searched the term “tetrabutylammonium” or “tetrabutyl ammonium” and found it appeared in 51 patents of the roughly 5,000 or so issued last week on April 7. While not all these patents relate to phase-transfer catalysis (toner patents, TBAF for desilylation, others), most of them do. This indicates that phase-transfer catalysis is alive and well, at least for industrial chemists.
The first tetrabutyl ammonium patent in the 9 millions is shown in the diagram. It is a phase-transfer catalyzed esterification to form a phosphate ester. What is interesting about this reaction is that most phosphate esters made using PTC react a phosphoryl chloride with a deprotonated hydroxyl (alkoxide or phenoxide). This procedure transfers and reacts a potassium phosphate salt with an alkyl hailde.
Forty four years after Starks published the first PTC publication in JACS, it is clear that when industrial chemists need high performance for their reactions, phase-transfer catalysis really does deliver. If it didn’t, PTC would have died a natural death as a passing curiosity a long time ago. There does seem to be a lot more industrially interesting patent literature than academic focus, but that just indicates how valuable PTC technology is to people like us who must develop profitable processes as our primary occupation.
I have been enjoying phase-transfer catalysis since US patents were in the 3 millions (almost 39 years) and I intend to enjoy reviewing PTC patents forever.
Now contact Marc Halpern to inquire about PTC Training or PTC Process Consulting at your company.
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!).
