(441b) Process Intensification Via Batch-to-Continuous Transition in the Production of Lubricants
The production of succinimide dispersants occurs via amination of a poly-isobutylene succinimide anhydride (PIBSA) with a polyamine. The reaction proceeds via a two-step mechanism: An irreversible amination to an amide acid intermediate, followed by a reversible dehydration reaction to produce water and the desired dispersant molecule. A complete family of dispersants is made by varying molecular weight of PIBSA, structure of the polyamines, and stoichiometric ratio of the two reactants. In the batch process, the water that is co-produced with the desired dispersant product is continuously removed from the head space at the relatively high reaction temperatures, rendering the dehydration step effectively irreversible. In contrast, the presence of water in the continuous reactor renders the dehydration step incomplete due to reversibility and identifies water as a key âcontaminantâ in this reaction system. However, we find that water removal from the product stream in a subsequent evaporation step results in spontaneous decomposition of the amide acid to the desired dispersant product, resulting in quantitative recovery of the desired product which is chemically and physically indistinguishable from the batch product and fulfills commercial specifications. The presentation will present and discuss these findings and their implications for design of an intensified continuous process.