Phase-transfer catalysis excels in performing nucleophilic reactions involving nitrogen heterocycles. In this patent, a high energy plasticizer used in explosives is produced by the addition of the nitrogen atom of 3,3-dinitroazetidine to a double bond.
We speculate that the inventors wanted to work under mild conditions to avoid possible safety incidents with the high-energy dinitroazetidine and product. PTC excels in achieving mild conditions by reducing the energy of activation of reactions in multiple ways. For example, it appears that solid KOH was used as the base, making this a solid-liquid PTC reaction. This limits the amount of water of hydration of the nitrogen nucleophile that could reduce its nucleophilicity that might be the reason they could work at room temperature. The use of nonpolar toluene further rejects water of hydration that may be transferred into the organic phase and reduce nucleophilicity (solid KOH usually contains water). We initially wondered why that large of an excess of the enone was used, but that could be due to making sure that there is no residual 3,3-dinitroazetidine remaining for safety reasons.
The lesson from this patent and the body of PTC literature is that if you need to N-alkylate a heterocycle or perform other addition reactions of nitrogen heterocycles, you should always consider phase-transfer catalysis.
Now contact Marc Halpern of PTC Organics to assure that your company benefits from the highly specialized expertise of PTC Organics Inc. in industrial phase-transfer catalysis to achieve low-cost high performance green chemistry using phase-transfer catalysis.
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!).
