Biorefining of rice bran oil: acrylate functionalization

Abstract

ABSTRACT

Objective: To obtain partially-acrylated refined rice bran oil using a combined H₂O₂/Novozym 435 epoxidation followed by acrylate group insertion.

Design/methodology/approach: Once epoxidized with H₂O₂/lipase Novozym 435, refined rice bran oil was acrylated via epoxy ring cleavage using triethanolamine as catalyst and 4-methoxyphenol as inhibitor. Conditions for functionalization included temperature (T=100 and 110ºC) and reaction time (t=3 and 4 hours), as well as the ratio g epoxidized oil vs g Acrylic Acid (1.5 and 2.0). To monitor functionalization, we evaluated the iodine value (IY), saponification value (IS), oxygen-oxirane content (COO), as well as FTIR and ¹H NMR analysis, thus allowing the %Acrylation to be estimated.

Results: ¹H NMR studies suggest that the acrylation on rice bran oil was efficient, also confirmed by the evolution of IY, IS and COO values. Using COO, we identified that the best acrylation condition was at T=110ºC, t=3 hours, and g oil vs g Acrylic Acid=1.5, allowing a %Acrylation of 85.89%.

Limitations on study/implications: Partially-acrylated rice bran rice oil can become an intermediate product in the biorefining of this oil, and be used in the synthesis of crosslinked polymers.

Findings/conclusions: Refined rice bran oil was efficiently acrylated using two consecutive steps, initially H₂O₂/Novozym 435 epoxidation, followed by functionalization with acrylate group.