Tetrabutyl ammonium bromide was used to make “cyclic carbonated soybean oil” (CSBO) from epoxidized soybean oil and carbon dioxide. While this reaction is catalyzed by bromide solubilized by the organophilic tetrabutylammonium cation, it is not a phase-transfer catalysis reaction.
The mechanism starts with the attack of bromide on the epoxide to form a 2-bromoethyl alkoxide derivative. The alkoxide oxygen attacks carbon dioxide and the resulting organic carbonate anion displaces the bromide (regenerating the bromide anion catalyst) to form the cyclic carbonate.
The mechanism of the TBAB-catalyzed reaction of epoxides with carbon dioxide is similar to that shown in a PTC Reaction of the Month in 2014 shown here: http://phasetransfercatalysis.com/ptc_reaction/ptc-carboxylation-using-co2/.
The cyclic carbonated soybean oil (CSBO) was used as the starting material to produce a variety of foaming compositions for rigid foams by reaction with carbamates and amines. The rigid foams had higher tensile strength, tear strength and other properties desirable for rigid foam. These foaming compositions also had environmental advantages related to the absence of chloride or isocyanate in the final product.
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!).
