(76c) Characterization of Non-Traditional Reactors for Scale up of Highly Branched Polymers

Turbulent immiscible liquid-liquid systems produce functionalized highly branched polymers via hydrolysis and condensation reactions. Due to simultaneous and interdependent physics, including coalescence, dispersion, heat and mass transfer, and competitive consecutive chemical reaction, time dependent mixing characteristics impact the resulting material produced.

Well characterized mixing equipment such as stirred tank reactors have well established rules for designing and scaling mixing dependent processes. Specific guidelines exist for both geometric and operational parameters such as load volumes, tank and impeller diameters, impeller types, number and location, and reactant addition strategies. Pump loop systems, however, have not been explicitly studied in the literature; therefore, scaling guidance for these systems is limited. Parallels can be drawn between well characterized stirred tank systems and pump loop operation, however, there are more independent design and operational variables in pump loop systems that increase the level of difficulty in process scaling over that of the stirred tank design.

Additionally, highly branched polymers can grow in three dimensional space as a function of time. Reaction conditions as a function of time influence how the structure of these species build^[1]. Different mixing conditions throughout different zones of a pump loop system can shift the instantaneous growth of a molecule between different reaction mechanisms. Therefore understanding what aspects of pump loop system design have the largest influence in how molecules build is essential to successfully scaling a process from lab to commercial scale.

REFERENCES

1. Brinker, C.J., “Hydrolysis and Condensation of Silicates: Effects on Structure”, Journal of Non-Crystalline Solids, V100, 1988, Pg 31-50, North Holland, Amsterdam. Elsevier Science Publishers B.V.