Reactivity and structure: epoxidation of cottonseed oil and the corresponding fatty acid methyl ester

Abstract

Vegetable oils and their functional derivatives are considered good alternatives to replace petroleum-derived products due to their low toxicity, renewability and biodegradable properties. Due to the high viscosity of vegetable oils, the current practice is to transesterify them into fatty acid methyl esters (FAME) to decrease reaction mixture viscosity. The use of FAME instead of vegetable oils towards the reactivity of functionalization can have an effect. To better understand the correlation between the reactivity and structure of vegetable oils, the comparison between the epoxidation of cottonseed oil (CSO) and their corresponding fatty acids methyl ester (CSO-FAME) was carried out in this study via percarboxylic acids, produced in-situ.A first comparison between the reactivity of performic and perpropionic acids was investigated. The effects of reaction temperature, HP/PA ratio, and catalyst loading on the epoxidation of CSO and CSO-FAME were evaluated. Important analytical work was done by using FTIR, NMR, GPC and titrations to track the reaction extent and the nature of ring-opening products. The results show that CSO-FAME has a faster reaction rate both in epoxidation and ring-opening reactions. The use of perpropionic acid decreases the side reaction of ring-opening. The kinetics of CSO epoxidation was found to be faster than CSO-FAME.

Comparative aspects on the epoxidation of soybean oil and high oleic soybean oil

“…Within this, it may be plausible to assume that the steric hindrance caused by the first epoxy group generated in a chain could affect the epoxidation reaction in the second and third double bonds in this chain, with a kinetic rate slower than the first epoxidation. Moreover, the steric hindrance can be intensified after ring opening reactions with the generation of oligomers between previously epoxy groups, as stated in a recent study (Meng et al, 2023). The hypothesis of different kinetic rates for different double bonds is the main reason that the kinetic modeling was modified from our previous work (Olivieri et al, 2020).…”

“…In typical conditions, the system also tends to present undesired reactions of performic acid decomposition and nucleophilic ring‐opening reactions of the epoxy group (Campanella & Baltanás, 2005a, 2005b, 2005c, 2006; Olivieri et al, 2020; Santacesaria et al, 2011). In addition, a recent study presented the possibility of an oligomerization reaction occur after the ring opening (Meng et al, 2023). Figure 1 illustrates the main reactions and the interfacial mass transfer to epoxidize SO and HOSO, aiming to produce ESO and EHOSO, respectively.…”