Abstract
Catalytic hydrogenation of linoleic acid was studied on Ir/Al2O3. A detailed analysis of geometrical and positional isomers of octadecenoic acid (18:1) in the products was performed by capillary gas-liquid chromatography with a new capillary column coated with isocyanopropyl trisilphenylene siloxane (TC-70). Well-resolved peaks of 10 species of 18:1 were observed in the product. In addition to monoenoic acid isomers, four species of trans-dienoic isomers and conjugated dienoic isomers were found. From the distribution of 18:1 isomers, it was found that the double bond closer to the methyl end (Δ12) showed higher reactivity than that closer to the carboxyl end (Δ9) for hydrogenation. Because cis-8 18:1 and trans-8 18:1 were not observed but cis-10 18:1 and trans-10 18:1 were observed in the products, the double-bond Δ9 did not migrate to the carboxyl end but migrated to the methyl end. On the other hand, the Δ12 bond migrated to both methyl and carboxyl ends. From the distribution of 18:1 isomers in the reaction pathway, the hydrogenation of linoleic acid proceeds via half-hydrogenation states. Cis-18:1 isomers were produced predominantly in the initial stage of the reaction, while trans-18:1 isomers were produced during progress of the reaction. The cis/trans and positional isomerization took place by readsorption of 18:1 produced by the partial hydrogenation of linoleic acid.
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References
Martin, C., TFAs (trans Fatty Acids)—a Fat Lot of Good?, in Chemistry in Britain, Vol. 32, 1996, The Royal Society of Chemistry, London, pp. 34–36.
Mensink, R.P., and M.B. Katan, Effect of Dietary trans Fatty Acids on High-Density and Low-Density Lipoprotein Cholesterol Levels in Healthy Subjects, N. Engl. J. Med. 323:439–445 (1990).
Katan, M.B., R.P. Mensink, A. van Tol, and P.L. Zock, Trans Fatty Acid and Lipoproteins, Int. Congr. Ser. 1066:258–261 (1995).
Ratnayake, W.M.N., P.R. Hollywood, E. O’Grady, and G. Pelletier, Fatty Acids in Some Common Food Items in Canada, J. Am. Coll. Nutr. 12:651–660 (1993).
Chardigny, J.M., J.L. Sébédio, P. Juanéda, J.M. Vatèle, and A. Grandgirard, Occurrence of n-3 trans Polyunsaturated Fatty Acids in Human Platelets, Nutr. Res. 13:1105–1111 (1993).
Ratnayake, W.M.N., and J.L. Beare-Rogers, Problems of Analyzing C18 cis- and trans- Fatty Acids of Margarine on the SP-2340 Capillary Column, J. Chromatogr. 28:633–639 (1990).
Official Methods and Recommended Practices of the American Oil Chemists’ Society, Champaign, 1992, Method 1c-89.
Mossoba, M.M., R.E. McDonald, J.Y.T. Chen, D.J. Armstrong, and S.W. Page, Identification and Quantitation of trans-9,trans-12-Octadecadienoic Acid Methyl Ester and Related Compounds in Hydrogenated Soybean Oil and Margarines by Capillary Gas Chromatography/Matrix Isolation/Fourier Transform Infrared Spectroscopy, J. Agric. Food Chem., 38:86–92 (1990).
Ratnayake, W.M.N., R. Hollywood, and E. O’Grady, Fatty Acids in Canadian Margarines, Can. Inst. Sci. Technol. J. 24:81–86 (1991).
Duchateau, G.S.M.J.E., H.J. van Oosten, and M.A. Vasconcellos, Analysis of cis and trans-Fatty Acid Isomers in Hydrogenated and Refined Vegetable Oils by Capillary Gas-Liquid Chromatography. J. Am. Oil Chem. Soc. 73:275–282 (1996).
Wolff, R.L., and C.C. Bayard, Improvement in the Resolution of Individual trans-18:1 Isomers by Capillary Gas-Liquid Chromatography: Use of a 100-m CP-Sil 88 Column, Ibid.: 1197–1201 (1995).
Mossoba, M.M., R.E. McDonald, J.A.G. Roach, D.D. Fingerhut, M.P. Yuravecz, and N. Sehat, Spectral Conformation of trans Monounsaturated C18 Fatty Acid Positional Isomers, Ibid.:125–130 (1997).
Kitayama, Y., M. Muraoka, M. Takahashi, T. Kodama, H. Itoh, E. Takahashi, and M. Okamura, Catalytic Hydrogenation of Linoleic Acid, Ibid.:1311–1316 (1996).
Ratnayake, W.M.N., and G. Pelletier, Positional and Geometrical Isomers of Linoleic Acid in Partially Hydrogenated Oils, Ibid.:95–105 (1992).
Wolff, R.L., M. Nour, and C.C. Bayard, Participation of the cis-12 Ethylenic Bond to cis-trans Isomerization of the cis-9 and cis-15 Ethylenic Bonds in Heated α-Linoleic Acid, Ibid.:327–332 (1996).
Kitayama, Y., M. Muraoka, M. Takahashi, and M. Okamura, Catalytic Hydrogenation of Linoleic Acid over Platinum Group Metals Supported on Alumina, Ibid.:525–529 (1997).
Coenen, J.W.E., The Rate of Change in the Perspective of Time, Chem. Ind. 6:709–722 (1978).
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Kitayama, Y., Takahashi, M., Sugiyama, H. et al. Gas-liquid chromatographic analysis of geometrical and positional octadecenoic and octadecadienoic acid isomers produced by catalytic hydrogenation of linoleic acid on Ir/Al2O3 . J Amer Oil Chem Soc 75, 27–32 (1998). https://doi.org/10.1007/s11746-998-0005-z
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DOI: https://doi.org/10.1007/s11746-998-0005-z