As we teach in our 2-day course “Industrial Phase-Transfer Catalysis” hydration is often the #1 factor that determines the amount of profit generated by a commercial PTC processes. This Dow Corning patent by DePierro and Reisch that issued this month illustrates the high sensitivity of solid-liquid PTC processes to hydration in a narrow range of added water. It is very important to be aware of the sensitivity because too many development teams overlook this important impact on profit when they are not aware of this sensitivity and they either unnecessarily lose yield or experience high variability from batch to batch due to minor changes in moisture level of the solid reactant.
This sensitivity to hydration is sometimes so significant that we have even seen differences in yield, reaction rate, etc. of large scale commercial solid-liquid PTC reactions, between batches when the solid reactant was taken from the middle of a container versus the top of the container that was exposed more to atmospheric moisture.
You really need to be aware of the levels of all hydrogen-bonding species in solid-liquid PTC reactions.
In this case, solid potassium sorbate was reacted with chloropropyl trimethoxy silane (CPTMS) in the presence of 1.7 mole% tetrabutylammonium bromide phase-transfer catalyst, Isopar G as solvent and stabiliziers. The graph shows the yield of the esterified product and the filtration rate after the reaction (to separate KCl byproduct) at a constant level of 3300 ppm methanol. Again, we must be aware of the level of all hydrogen-bonding species.
The inventors were very smart to test the effect of water at various levels up to 0.35% to understand the dramatic impact on yield. The inventors did not report the effect of water on reaction rate though they did mention that the reaction rate varied between 5 hours and 10 hours depending on reaction conditions. “The time required to complete the reaction varied depending on methanol and water concentration as well as temperature.”
Again, we teach process chemists and plant support chemists how to squeeze more profit from commercial solid-liquid PTC processes in our 2-day PTC course or by conducting PTC Process Consulting and PTC Contract Research. Don’t let your company make less profit by hesitating to take our PTC training, PTC Process Consulting or PTC Contract Research. The return on investment when contracting for PTC Organics’ services is often thousands of percent.
Now contact Marc Halpern of PTC Organics to improve process performance and R&D efficiency. The job you save may be your own!
