The background for this quat salt and similar salts that are used in synthesis (not as phase-transfer catalysts) is best described in US Patent 10,179,795 that was issued this month.
“Isotopically enriched boron-10 compounds, such as salts of polyhedral boranes can be used in research laboratories for the preparation of therapeutic agents for the boron neutron capture therapy of cancer (BNCT). However, these compounds are not commercially accessible. As a result, there is a need to provide a straightforward and easily scalable method for the synthesis, isolation, and purification of boron-10 isotopically-enriched compounds. “
“The present invention is directed to a process for the synthesis of mixtures of salts of polyhedral boranes and includes the steps of first, combining a methyltriethylammonium halide with an alkali metal tetrahydroborate in a reaction mixture; second, reacting the methyltriethylammonium halide and the alkali metal tetrahydroborate to form a methyltriethylammonium tetrahydroborate intermediate and an alkali metal halide; and third, pyrolizing the methyltriethylammonium tetrahydroborate intermediate to produce a product mixture comprising methyltriethylammonium decahydrodecaborate and methyltriethylammonium dodecahydrododecaborate. “
Examples 2 and 3 of this patent describe the synthesis and isolation of the salt shown in the figure.
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!).
