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
Publication Name
ChemPhotoChem
Volume
6
ISBN/ISSN
2367-0932
Edition
N/A
Issue
7
Pages Count
13
Location
N/A
Publisher
Wiley-VCH GmbH
Publisher Url
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Publisher Location
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Publish Date
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Date
N/A
EISSN
N/A
DOI
10.1002/cptc.202200007