Role of CO2 in mass transfer, reaction kinetics, and inter-phase partitioning for the transesterification of triolein in an expanded methanol system with heterogeneous acid catalyst

Fatty acid methyl ester (FAME) production via transesterification of triglycerides (TGs) over a heterogeneous acid catalyst is mediated by carbon dioxide in an expanded methanol system. A representative TG, triolein, is used to determine the mechanisms and interactions responsible for the improved yields over Nafion-NR50 in these system conditions. Namely, the system mass transfer limitations, reaction kinetics, and interphase partitioning behavior are explored by varying mixing conditions and catalyst characteristics over a time series of 4 h. It is found that CO2 enhances mass transfer leading to improved reaction yields and product profiles due to increased substrate transport to and from the catalyst surface. CO2 also contributes to catalyst expansion, leading to greater exposure of active sites and faster reaction kinetics. Initial reaction rate constants using methanol-soaked Nafion reflect pseudo-first-order kinetics. Finally, the substrate-reagent mediating properties of CO2 are discussed in reference to the varying reaction rates of TG and intermediate products. All three of these mechanisms contribute to CO2's multifaceted role in facilitating heterogeneously catalyzed reactions.

Title	Role of CO2 in mass transfer, reaction kinetics, and inter-phase partitioning for the transesterification of triolein in an expanded methanol system with heterogeneous acid catalyst
Creator	Soh, Lindsay
	Kwan, T. A.
	Chen, C. C.
	Zimmerman, J. B.
Publisher	ACS Sustainable Chemistry and Engineering
Academic Department	Chemical & Biomolecular Engineering
Division	Engineering
Organization	Lafayette College
Date Issued	November 2015
Date Available	2016-11-04T20:51:07Z
Type	Article
Language	English
Keyword	Biodiesel
	Methanolysis
	Heterogeneous catalysis
	Green chemistry and engineering
	Gas-expanded liquids
	CO2-exanded methanol
Bibliographic Citation	Soh, L., et al. (2015 Nov) "Role of CO2 in mass transfer, reaction kinetics, and inter-phase partitioning for the transesterification of triolein in an expanded methanol system with heterogeneous acid catalyst." ACS Sustainable Chemistry and Engineering 3 (11): 2669-2677.
Standard Identifier	DOI 10.1021/acssuschemeng.5b00472
Standard Identifier	Handle 10385/2153
Permalink	http://hdl.handle.net/10385/2153
Rights Statement	In Copyright
Rights Holders	American Chemical Society