This patent describes the chlorination of sucrose-6-acetate with chlorodimethylformiminium chloride to form sucralose using a 2-phase system with DMF and perfluorooctane. The inventors used Aliquat 336 and observed 3 phases in the initial stages of the reaction at low temperature. The inventors state “Aliquat 336 helps to mix the co-solvent and chlorination mixture forming a third intermediate phase.” As we teach in the 2-day course “Industrial Phase-Transfer Catalysis,” PTC systems enjoy enhanced reactivity when a third intermediate phase can be created. This may be the case in this system. If so, then the three phases are DMF, perfluorooctane and a small phase rich in Aliquat 336. Upon heating to higher temperature for an extended period of time, two phases are formed from the 3-phase system. The perfluorooctane is recovered and recycled without purification.
In most 3-liquid phase PTC systems, the phases are an aqueous phase, a non-polar organic solvent such as heptane and the third intermediate phase is rich in a phase-transfer catalyst such as tetrabutylammonium. In such systems, Aliquat 336 would distribute into the non-polar organic phase, but in this patent the inventors used DMF and perfluorooctane. This is quite different than most 3-liquid phase PTC systems.
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!).
