Methyl Oleate Synthesis by TiO2 Photocatalytic Esterification of Oleic Acid: Optimisation by Response Surface Quadratic Methodology, Reaction Kinetics and Thermodynamics
Journal Publication ResearchOnline@JCUAbstract
Methyl oleate, an example of a FAME (fatty acid methyl ester), was produced by oleic acid (OA) photoesterification with TiO2 and UVA light. Different parameters were evaluated and optimised: catalyst pretreatment, temperature (25–65°C), catalyst loading (1–30 % w/wOA) and oleic acid : alcohol molar ratio (1 : 3–1 : 55). Response surface quadratic methodology obtained by central composite rotational design (RSM-CCRD) was used to evaluate the main operational conditions of the photoesterification process. A high conversion of 98 % (±0.8) at 55 °C, 20 % TiO2 (w/wOA), and 1(OA) : 55(methanol) molar ratio was achieved. The photoesterification mechanism is furthermore proposed. The Langmuir-Hinshelwood kinetic model considered the forward and backward reaction as first-order fits with the best accuracy (R2 of 0.997). The thermodynamic results (ΔG338.15K=−20.75 kJ/mol, ΔH=13.75 kJ/mol, and ΔS=0.47 kJ/mol.K) indicate that the operating conditions are important, both to supply the energy requirement of the reaction, but also to increase the miscibility of the reactants.
Journal
ChemPhotoChem
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N/A
Volume
6
ISBN/ISSN
2367-0932
Edition
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Issue
7
Pages Count
13
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Publisher
Wiley-VCH GmbH
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EISSN
N/A
DOI
10.1002/cptc.202200007