An idea hit me when visiting an exhibit of a microreactor supplier at a trade show this month. More information on these microreactors is shown here.
In these microreactors, there were static mixers built in to the channel through which the reactants flow. As you increase the flow rate, you increase the agitation efficiency.
Most liquid-liquid PTC reactions show increased reactivity with increased agitation at low agitation efficiencies and then reactivity levels off as the reaction transitions from transfer rate limited (“T-Reaction”) to intrinsic reaction rate limited (“I-Reaction”). In other words, most PTC reactions achieve a maximum in productivity at some agitation level. Figuring out what that agitation efficiency is sometimes a crucial factor in developing the most effective industrial PTC process.
In classic stirred PTC systems, one examines effect of agitation by increasing the stirring speed of the agitator typically centered in the reactor and measuring the rate constant on the Y-axis and rpm on the X-axis. Using a microreactor, one can simply change the flow rate and observe at what flow rate the maximum reactivity is reached.
This is particularly important when working with water-sensitive compounds. Let’s say, for example, that we are reacting benzoyl chloride with a nucleophile. The benzoyl chloride can undergo non-catalyzed interfacial hydrolysis at high agitation efficiencies. In these cases, it is essential to determine the maximum reactivity while minimizing agitation in order to avoid the wasteful hydrolysis.
In this case, it might be useful to use a microreactor to perform this reaction and change the flow rate to determine the maximum ratio of the desired phase-transfer catalyzed nucleophilic substitution to the undesired hydrolysis side reaction.
In fact, if the results are very good, you might want to use the microreactor to actually do the commercial scale reaction and achieve high productivity with short heat history and realize other benefits.
If your company can benefit from achieving higher process performance in a shorter development time by having access to the best PTC expertise available, now contact Marc Halpern by E-mail or by phone at + 1 856-222-1146 to inquire about using phase-transfer catalysis to achieve low-cost high-performance green chemistry.
If you’re not sure if PTC can help your reaction, now fill out the form shown at http://phasetransfer.com/projectform.pdf and send it to Marc Halpern by fax at +1 856-222-1124 or by E-mail of a scanned copy. If we do not have a secrecy agreement already in place, please use “R-groups” instead of the exact chemical structures.
