Conversion of High Free Fatty Acid Lipid Feedstocks to Biofuel Using Triazabicyclodecene Catalyst (Homogeneous and Heterogeneous)

Abstract

Traditional biodiesel is produced from feedstocks such as vegetable oils and animal fats by converting the triglycerides with methanol in the presence of a homogeneous catalyst to produce fatty acid methyl esters (FAMEs). However, drawbacks of this process include an undesired glycerol byproduct and post-reaction processing that result in increased production costs. In this study, unrefined corn oil and waste restaurant grease containing high free fatty acids (FFA) were used to evaluate the ability of triazabicyclodecene (TBD), a non-ionic, guanidine base, to function in a high free fatty acid environment. Reactions were carried out using both methanol and dimethyl carbonate (DMC) as methylating agents. Although increasing amounts of FFAs reduced the conversion of triglycerides (TGs), the TBD catalyst, using either methanol or DMC, adequately esterified FFAs at moderate temperatures (60 °C) but was not effective in converting triglycerides. The homogeneous catalyst work aided in elucidating the reaction chemistry. This work also studied the ability of a heterogeneous catalyst (TBD supported on a layered double hydroxide) to convert both FFAs and TGs in which 80% conversion was seen for neat canola oil and 58% conversion for unrefined oil. This study illustrates that the TBD/DMC process is an effective and commercially viable method for producing sustainable biofuels.

Thermally Latent Bases in Dynamic Covalent Polymer Networks and their Emerging Applications

“…In the catalysis of numerous polymerization reactions, the conversion of fatty acid feedstocks to biofuel, and the catalysis of transesterification reactions in different covalent adaptable networks, i.e., vitrimers, unmodified TBD is considered as one of the most efficient organic catalysts. [ 5,13,42 ] All these examples underline the enormous application potential of the developed thermally latent equivalent TBD‐CA presented in this work. Throughout the following sections, the focus is specifically put on the thermolatent catalysis of dynamic transesterification within a covalently crosslinked polymer network.…”

A more efficient synthesis and properties of saturated and unsaturated starch esters

“…A guanidine base organocatalyst, 1,5,7-triazabicyclo[4.4.0]-dec-5ene (TBD), is particularly efficient in many transesterification processes, including transesterification of starch with a high DS (Borton et al, 2019;Orzolek et al, 2018;Söyler & Meier, 2017). Studies on the optimization of TBD-catalyzed transesterification already exist.…”

“…It was concluded that a reaction at 115 • C was most efficient and after 12 h the DS did not increase any further (Schenzel et al, 2014;Söyler & Meier, 2017). However, a study shows (Borton et al, 2019) that constant purging of the reaction was needed to avoid carbonate uptake by TBD, lowering the reaction efficiency.…”

An Overview of the Classification, Production and Utilization of Biofuels for Internal Combustion Engine Applications

“…If the FFA value is lower than 1 mgKOH/g, a single-step transesterification process is adopted. Due to the low quality of some of the feedstocks, especially waste cooking oil, waste animal fats, recovered fats, and grease, pretreatment processes are required before transesterification [155,156].…”