The Industrial Phase-Transfer Catalysis Experts

PTC Tip of the Month E-Newsletter

PTC Tip of the Month - October 2017

Device to Determine Conversion Without Taking Samples Especially in Solvent-Free PTC Applications

By Marc Halpern, the leading expert in industrial phase-transfer catalysis.

An exhibit at the 2017 Specialty & Agro Chemical trade show displayed a system by FLEXIM based on measuring changes in the speed of sound in a liquid that can be calibrated to determine conversion of chemical reaction that we think may be particularly useful for solvent-free phase-transfer catalysis reactions or in PTC systems that use solvent and are not overly dilute.

The advantage of the system is that no samples need to be taken and conversion can be monitored continuously after a calibration curve is established.


The principle is based on the fact that the speed of sound transmitted through a liquid is different as the density changes. The system uses a sound wave generator and a sound wave frequency detector, both attached externally to the outside walls of the reactor (shown on the left side in the picture). The reactor can be made of just about anything…glass, metal, plastic, etc. the system is quite sensitive and can discern between 10.0% aqueous NaCl and 10.1% aqueous NaCl, for example.

In Starks’ original solvent-free PTC reaction reported in 1971 in which octyl chloride was converted into octyl nitrile, the difference in densities between these two materials could be used to determine the relative compositions of the two materials, thereby determining conversion.

The main application of FLEXIM’s technology is non-invasive ultrasonic flow measurement.

PTC Organics would be happy to work with your company and the manufacturer of this system to evaluate the applicability of this system to continuously determining conversion of your PTC application without sampling, by integrating our highly specialized expertise in industrial phase-transfer catalysis with your company’s needs and the expertise of the manufacturer of the unit. Now contact Marc Halpern of PTC Organics to explore custom developing a solution for your solvent-free PTC application (or concentrated PTC system).

About Marc Halpern

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!).

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