Methyl THF is sometimes used when one wants some of the solubility properties of THF but also needs to make two phases with water, like in liquid-liquid PTC reactions. Methyl THP (4-methyl tetrahydropyran) takes this concept one step further by having one extra carbon atom.
According to Kuraray, a supplier of methyl THP, methyl THP can contain up to 1.4 wt% water versus 4.4 wt% water for methyl THF. The amount of water that can hydrate anions when transferred into the organic phase in PTC systems is often crucial, so Me THP may make a difference in hydration-sensitive PTC systems. Methyl THP boils at 105 C versus 80 C for Methyl THF which is good when higher temperature reactions are needed. The azeotrope of Methyl THP with water contains 19% water versus 15% for methyl THF which means that Me THP systems can be dried faster by azeotropic drying. Methyl THP is more stable to auto-oxidation than methyl THF and THF.
The tradeoff is that methyl THP is more expensive than methyl THF. The tradeoff between price and performance should always be analyzed on a case by case basis.
One of the greatest advantages of phase-transfer catalysis is the ability to have flexibility when choosing solvent. If you have special needs or constraints for using certain solvents or avoiding certain solvents, please contact Dr. Marc Halpern of PTC Organics to discuss improving your process performance, including choice of solvent in phase-transfer catalysis 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!).
