https://doi.org/10.15255/KUI.2014.024
Published: Kem. Ind. 65 (1-2) (2016) 17−24
Paper reference number: KUI-24/2014
Paper type: Review
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Application of NMR Spectroscopy in the Analysis of Biodiesel

J. Parlov Vuković

Abstract

In this review, the most important and most frequently used one and two dimensional NMR techniques for biodiesel analysis have been described. Biodiesel is an ecologically accepted alternative fuel consisting of saturated and non-saturated methyl esters of fatty acids. Owing to the fact that analysis of biodiesel chemical composition and properties pose a challenge to analytical chemists, novel and more efficient analytical techniques and methods are being developed constantly. In that respect, NMR spectroscopy is an excellent method, which can provide a wealth of information on the composition and structural properties of biodiesel. NMR can be used for determination of the iodine value of biodiesel, fatty acid profile, and percentage of fatty acid methyl esters. Furthermore, NMR spectral analysis can give valuable data on raw materials used for biodiesel production and the process of trans-esterification can be monitored. By the application of ¹H and ¹³C NMR techniques, the composition and structure of additives for preventing the growth of microorganisms can be determined. For that purpose, apart from ¹H and ¹³C spectra, ³¹P spectra are used as well. Also, composition of acetylglycerol mixtures and corresponding by-products of biodiesel synthesis can be analysed. NMR spectroscopy has proven useful in analysis of hydrotreated vegetable oils, which have better fuel properties than biodiesel produced via transesterification, and their application improves engine fuel economy. In this paper, representative NMR spectra of diesel, biodiesel and hydrotreated vegetable oil and those of biocide samples recorded in the Laboratory for NMR spectroscopy of INA d. d. are given. The advantages of using NMR spectroscopy in biodiesel analysis and determination of its properties are discussed.

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Keywords

NMR spectroscopy, biodiesel, fatty acid methyl esters, hydrotreated vegetable oils