Acetylation of Glycerol over Highly Stable and Active Sulfated Alumina Catalyst: Reaction Mechanism, Kinetic Modeling and Estimation of Kinetic Parameters

Abstract

The Langmuir–Hinshelwood–Hougen–Watson (LHHW) kinetic model was developed for acetylation of glycerol over highly stable and active 2 M SO42−/γ‐Al2O3 catalyst. The apparent reaction rate constants were determined by numerically solving the differential rate equations using ode23 tool in MATLAB coupled with the genetic algorithm optimization technique. The estimated rate constants were used to obtain the activation energy and pre‐exponential factor by using the Arrhenius equation. The estimated activation energy for direct acetylation of glycerol to monoacetylglycerol and diacetylglycerol was 7.2 kJ mol−1, for acetylation of monoacetylglycerol to diacetylglycerol was 37.1 kJ mol−1, and for acetylation of diacetylglycerol to triacetylglycerol was 26.6 kJ mol−1, respectively.

Kinetic studies on the synthesis of fuel additives from glycerol using CeO2–ZrO2 metal oxide catalyst

“…In contrast, the lower values of activation energy and higher values of rate constant for the first and second reaction favoured the faster formation of monoacetin and diacetin. The high yield of diacetin can also be attributed to the direct acetylation of glycerol in the early phases as suggested by the reaction mechanisms proposed in the literature (Pankajakshan et al, 2018).…”

“…9) displays a linear behaviour and the activation energy values of 5.34, 16.40, and 43.57 kJ.mol -1 were calculated for the formation of monoacetin, diacetin, and triacetin, respectively. Pankajakshan et al (2018) reported the kinetic parameters for glycerol acetylation using a sulphated γ-Al2O3 catalyst. The very high activation energy for the third reaction and low value of rate constant could explain the lower yield of triacetin obtained by the authors.…”

Effect of Basic Promoters on Porous Supported Alumina Catalysts for Acetins Production

“…In this sense, the exceptional properties of alumina-based catalysts, such as porosity, large specific surface area, chemical stability and their addressable Lewis and Brønsted acid sites for glycerol conversion, have made them of particular interest in the EG reaction [3,13,[17][18][19][20]. However, the main disadvantages of these types of solid acid catalysts for glycerol esterification are their low water tolerance, leaching of active sites and low selectivities to the acetins, which significantly restrict their performance in the reaction [5,[17][18][19][20].…”

“…In this sense, the exceptional properties of alumina-based catalysts, such as porosity, large specific surface area, chemical stability and their addressable Lewis and Brønsted acid sites for glycerol conversion, have made them of particular interest in the EG reaction [3,13,[17][18][19][20]. However, the main disadvantages of these types of solid acid catalysts for glycerol esterification are their low water tolerance, leaching of active sites and low selectivities to the acetins, which significantly restrict their performance in the reaction [5,[17][18][19][20]. Overall, strategies for acidity modulation of the catalysts that permit the control of acid strength, types of acid sites and surface acidity to minimize the problem on water deactivation and subsequently improving the selectivity of diacetin and triacetin are vastly documented [6,11,15,20].…”

Αξιοποίηση Παραγώγων Της Βιομάζας Προς Παραγωγή Πετροχημικών Πρώτων Υλών

“…Monoacylglycerol is a valuable food additive, while the others are fuel additives that reduce viscosity, when mixed with diesel, or improve anti-knocking properties, when mixed with gasoline. [167,168] Scheme 1.18. Catalytic glycerol esterification [169] In a one-pot glycerol esterification, at 110 o C, over guanidine derivatives, 78% selectivity to monoglycerides can be achieved, starting from (CH 3 )OCOC 11 H 23 [169] combined selectivity, without formation of undesired by-products, such as isobutylene oligomers [173].…”