A DFT investigation of methanolysis and hydrolysis of triacetin

Abstract

The thermodynamic and kinetic aspects of the methanolysis and hydrolysis reactions of glycerol triacetate or triacetin, a model triacylglycerol compound, were investigated by using Density Functional Theory (DFT) at the B3LYP/6-31++G(d,p) level of calculation. Twelve elementary steps of triacetin methanolysis were studied under acid-catalyzed and base-catalyzed conditions. The mechanism of acid-catalyzed methanolysis reaction which has not been reported yet for any esters was proposed. The effects of substitution, methanolysis/hydrolysis position, solvent and face of nucleophilic attack on the free energy of reaction and activation energy were examined. The prediction confirmed the facile position at the middle position of glycerol observed by NMR techniques. The calculated activation energy and the trends of those factors agree with existing experimental observations in biodiesel production

Cosolvent Effects on the Drug Release and Depot Swelling in Injectable In situ Depot-Forming Systems

“…As is known, triacetin hydrolyzes to glycerol and acetic acid when it dissolves in the water. Apart from this, the heterogeneous degradation of the depot (shown in our previous study)30 may also lead to a lowered pH inside the depot over time, which can then catalyze triacetin decomposition 30. Triacetin plays an important role in delaying polymer phase inversion at the early stage and plays a less important role in the later stages.…”

Density functional theory study of the reactivity and electronic structure of the transesterification of triacetin in biodiesel production via a sulfated zirconia heterogeneous catalysis

“…a) because this molecule preserves the electronic properties contained in long‐chain triglycerides, as previously presented. It is known that the overall reaction of triacetin has six possible pathways including 12 elementary steps . The experimental work of López et al suggests a possible route to achieve transesterification as a three‐step reaction to give biodiesel (Scheme ).…”

“…It is known that the overall reaction of triacetin has six possible pathways including 12 elementary steps. [23] The experimental work of L opez et al [17] suggests a possible route to achieve transesterification as a three-step…”

“…It has been found that the transesterification of triglycerides occurs in three separate processes such that the free fatty acids interact with the alcohol to give a fatty acid alkyl ester, diglyceride, and monoglyceride as intermediates and then the final glycerol byproduct. Additionally, it has been demonstrated theoretically and experimentally that triglyceride may be successfully modeled with a smaller molecule, such as triacetin, as it possesses the same chemical functionality. It is important to note that this approximation may overestimate some interactions because of the lack of the long alkyl chains present in triglycerides, which may introduce steric and hydrophobic repulsions with respect to the heterogeneous catalyst.…”

Resolutions of the Coulomb Operator: VII. Evaluation of Long-Range Coulomb and Exchange Matrices

“…Our test cases comprise typical biomolecules (water clusters, 29 polypeptides, 30 and triglyceride 31 ), a conducting system (buckminsterfullerene 32 ), and a weakly interacting system (helium cluster 33 ). Geometries are described in the references given here.…”