DOI: https://doi.org/10.9767/bcrec.20768

Skeletal Isomerisation of Methyl Oleate Using Zeolite‑β: Catalyst Activity and Conversion Assessment

1Chemical Engineering and Analytical Science Department, Faculty of Engineering and Physical Science, The University of Manchester, Manchester M60 1QD, United Kingdom

2Department of Chemical Engineering, University of Engineering and Technology, 54890, Lahore, Pakistan

3Institute of Chemical Sciences, Bahauddin Zakariya University, Multan, 60800, Pakistan

Received: 11 Jun 2026; Revised: 14 Oct 2026; Accepted: 15 Oct 2026; Available online: 25 Oct 2026; Published: 26 Dec 2026.
Editor(s): Istadi Istadi
Open Access Copyright (c) 2026 by Authors, Published by BCREC Publishing Group
Creative Commons License This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.
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Abstract

Biodiesel’s cold flow properties, limited by the crystallisation of saturated and trans‑unsaturated fatty acid methyl esters (FAMEs), can be improved through skeletal isomerisation of unsaturated FAMEs to branched‑chain isomers. Zeolite‑β has shown promise for this reaction, but detailed characterisation of the complex isomer mixture remains challenging. This study investigates the isomerisation of methyl oleate over Zeolite‑β (H‑β) in a batch reactor at 200 °C and atmospheric pressure for 6 h, using 10 wt% catalyst. A conversion of 92.2% was achieved, confirming high catalyst activity. However, analysis by gas chromatography–mass spectrometry (GC–MS) with a polar BPX70 column revealed significant limitations: the product chromatogram showed extensive peak overlap, and the mass spectra of positional, geometric, and branched‑chain isomers were nearly identical, preventing reliable determination of selectivity and yield. The work highlights that conventional GC–MS is inadequate for full isomer speciation in such complex mixtures. Advanced techniques such as comprehensive two‑dimensional GC (GC×GC), silver‑ion chromatography, or high‑resolution mass spectrometry are required for accurate isomer identification. These findings establish a performance baseline for Zeolite‑β and delineate the analytical challenges that must be addressed to enable rational catalyst and process optimisation for improved biodiesel cold flow properties.

Keywords: Biodiesel, Cold flow properties, Skeletal Isomerisation, Zeolite‑β, fatty acid methyl esters

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Section: Original Research Articles
Language : EN
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