(389e) The Evolution of Process Understanding Through Micromixing and Mass Transfer Studies In the Successful Development of a Specialty Chemical Process

Researchers who develop new specialty chemical products are often faced with a variety of potentially conflicting rate processes which can influence reaction selectivity and final product properties.  As the researchers’ understanding of the process develops through laboratory studies and pilot plant trials, the original process paradigms must be critically examined in order to assure successful commercial implementation.

This paper examines the evolution of process understanding in the development of a specialty chemical product.  The critical reaction step could produce the desired product (R) and two by-products (Q and S) by the reactions:

A + B →  Q

A + B →  R

R + B → S

Researchers needed to minimize potential losses of the very expensive reagent B and the moderately expensive reagent A in the pilot plant.  Recognizing the series-parallel nature of the R and S reactions, researchers used the Bourne reactions in the laboratory and found a strong correlation between the selectivity of the Bourne reactions and the production of R and S in the critical reaction step over a wide range of laboratory process conditions.  The Bourne reactions were used in the pilot plant to establish operating conditions for the critical reaction step.  The desired selectivity of the critical reaction step was achieved in the initial scale-up with high overall yield on the expensive reagents.

Though the initial results were rather satisfying, certain observations on the initial and subsequent scale-up campaigns indicated that the process understanding was not complete.  This paper will further examine those observations and look in more detail at the phases, components, and rate processes controlling the process.  Consideration of both the mass transfer effects and micromixing led to more complete process understanding and a highly successful commercial start-up.