Title

Thermodynamic and Kinetic Analysis of γ-Valerolactione Ring Opening in Multiphasic Reactor

Date of Award

May 2019

Degree Name

Master of Science (MS)

Department

Biomedical and Chemical Engineering

Advisor(s)

Jesse Q. Bond

Keywords

GVL ring opening, liquid-phase kinetics, solution thermodynamics

Subject Categories

Engineering

Abstract

In the biomass processing landscape, γ-valerolactone (GVL) is a popular intermediate platform chemical that can be used to produce a range of fuels and chemicals through catalytic upgrading. This project is the ring opening of GVL to form pentenoic acid (PEA) isomers, which are a family of C5 alkene-acids, whose molecular weight and chemical flexibility make them appropriate for the production of polymers, solvents, and diesel fuels.

GVL ring opening is kinetically favorable and occurs with a reasonable rate of reaction at moderate temperatures. It is proton-mediated, and it proceeds in the presence of various homogeneous (e.g., H2SO4) and heterogeneous (e.g., H-ZSM-5) Bronsted acids. In order to avoid detrimental side reactions, such as decarboxylation and polymerization, it is desirable to carry out ring opening at low temperatures; however, the reaction is endothermic and severely constrained by chemical equilibrium under practical conditions. Our hypothesis is that a well-designed biphasic reactor can bypass this equilibrium constraint and deliver good PEA yields at low. Specifically, we propose that preferential solvation PEA in an extracting organic phase should drive high GVL conversions despite an unfavorable equilibrium position at low temperatures.

In order to design an appropriate reactor, it is essential to develop a comprehensive understanding of both solution thermodynamics and the kinetics of GVL ring opening in a range of solvent environments. To this end, we have performed extraction experiments to allow regression of empirical Margules parameters to estimate species activity coefficients in both aqueous and organic media, and we have studied the kinetics of GVL ring opening in both single and biphasic systems. Based on these results, biphasic reactors were simulated under a range of temperatures and solvent environments to identify operating conditions that can deliver improved single-pot yields of PEA on industrially tractable time scales.

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