Process Intensification by Integrated Reaction and Distillation for Synthesis of Bio-Renewable Organic Acid Esters

Organic acid esters, produced from bio-based organic acids and alcohols, are truly bio-renewable, green chemicals that are promising replacements for halogenated and other petroleum-based solvents, lubricants, and plasticizers. With current uncertainty regarding the future of ethanol and other alcohols as biofuels, and with the availability of organic acids via fermentation, there exists strong motivation to develop esters as viable commodity bio-chemicals to support and expand the existing bio-renewable infrastructure. Esters are advantageously produced using reactive distillation, where simultaneous reaction and separation take place in the same process unit. Because of challenges in some esterification reactions, where reactions are slow and limited thermodynamically, there exists a need for breakthrough advances in reactive distillation to make the production of esters more competitive economically with their petroleum-based counterparts. This project will develop and demonstrate advanced reactive distillation concepts for esterification that reduce energy consumption and lower capital equipment costs. The major objective is to develop and experimentally validate design concept(s) of heat-integrated reactive distillation with side reactors and divided-wall columns for esterification of bio-based organic acids with alcohols and to evaluate techno-economic viability for near-term commercialization. The Phase I proposed project focuses on an innovative, heat-integrated reactive distillation with side reactors and divided-wall column for synthesis of organic acid esters. AspenPlus process analysis will be performed based on the available kinetic data for esterification of citric acid with ethanol and it will be validated by preliminary reactive distillation experiments. The experimental part of the Phase 1 research will use the reactive distillation facility at Michigan State University with a pre-reactor and one side reactor coupled to a distillation column. Heat integration will be examined for energy efficiency and maintaining temperatures in side reactors for maximizing the catalyst utilization. Phase II research will focus on pilot-scale experiments and industrial participation to develop design basis for a commercial process. Commercial Applications and Other Benefits: The major benefits are: a) synthesis of high-value green chemicals from bio-based ethanol and organic acids; and b) U.S. competitiveness in manufacturing of bio-based plasticizers and solvents.