This month’s PTC Catalyst of the Month is not a phase-transfer catalyst but it looks like it could be an amazing chiral phase-transfer catalyst. This compound looks half like a crown ether and half like a Maruoka-type chiral framework. In other words, it looks like a molecule designed by someone who understands that organized binding is where the real power is. When I saw this crown-Maruoka hybrid, it reminded me of the powerful Greek mythology centaur.
The patent, Shibata, T.; Shinkura, S.; Kawahara, N.; Fujioka, Y.; Terada, M. (Daicel Corporation) US 2026/0062375, 05-Mar-2026, is a chromatography patent. It is directed to amine separation, and the examples around this compound describe chiral separation of dl-1-phenylethylamine and related systems.
The crown-ether-like portion of the molecule suggests selective complexation. The rigid chiral aromatic scaffold suggests organized asymmetry. Put those together and you get a recognition element that can discriminate among guests in a highly structured way.
In PTC, we use that kind of thinking all the time, even if we do not always say it explicitly. We think about cavity fit, ion pairing, hydration, steric accessibility, rigidity, and multi-point interaction. We think about how a molecular architecture changes where an ion wants to be, how tightly it is bound, and how selectively it behaves. Crown ethers, PEGs, cryptands, phase-bound systems, and chiral PTC create a microenvironment that controls binding and therefore controls outcome.
This patent is a nice reminder that the same thought process extends beyond PTC.
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!).
