The Industrial Phase-Transfer Catalysis Experts

PTC Tip of the Month E-Newsletter

PTC Catalyst of the Month - January 2025

Tetrabutyl Ammonium Imidazolate

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

A very simple procedure was described for the preparation of tetrabutyl ammonium imidazolate in Pyun; L., Jung; I., Min; B, Lee; J., Jeong; J. (SK Innovation Co. Ltd) US Patent Application Publication 2025/0001390, 02-Jan-2025. This quat salt was used for a carbon dioxide absorbent ionic liquid.

5.00 g (18.0 mmol) of tetrabutylammonium chloride, 1.37 g (18.0 mmol) of sodium imidazolate, and 20 mL of ethanol were added to 100 mL of RBF, and then stirring was performed at room temperature for 2 hours. The produced solid was filtered out of the reactant, and the filtrate was dried under vacuum at 50 deg C. for 15 hours to obtain 5.46 g (98%) of a light yellow oil.


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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