Methyl elaidate, hydrogenation

Conclusive evidence for the participation of 7r-allylic intermediates in double bond migration has been obtained from a study of the nickel-catalysed hydrogenation of the isomeric olefinic esters methyl oleate and methyl elaidate using tritium as a tracer [147]. It was also concluded that in this system cis—trans isomerisation occurred by an addition—abstraction mechanism. 

Figure 7. Methyl esters of unsaturated fatty acids as resolved on the 25%-cyanopropyl-25%-phenyl methyl siloxane DB-225. Split Injection to a 30m x 0.25mm column coated with a 0.25 m bonded film, hydrogen carrier at 46cm/sec, isothermal at 200 °C. Components 1, 14 1 methyl myristoleate 2, 16 1 trans methyl palmite-laidate 3, 16 1 cis methyl palmitoleate 4, 18 1 trans methyl elaidate 5, 18 1 cis methyl oleate 6, 18 2 trans methyl linolea-laidate 7, 18 2 cis methyl linoleate 8, 18 3 methyl linoleate ...

Infrared analysis for trans-octadecenoic acid is a standard method (Report of the Spectroscopy Committee, 1959). Good quantitative results for the trans-isomers are possible by infrared analyses, and such analyses are done routinely by many laboratories. Kauffman and Lee (1960) found good agreement between the infrared analysis and the gas-liquid partition chromatographic analysis of methyl elaidate in hydrogenated vegetable oil... 

Shape-selective hydrogenation of methyl oleate cis isomer) and methyl elaidate trans isomer) over Pt/ZSM-5. Reprinted with permission from Wiley-VCH Verlag(From Philippaerts A, Jacobs PA, Sets BF. Is there still a future for hydrogenated vegetable oils Angew Chem Int Ed 2013 52 5220—6). 

The Co2(CO)g-catalyzed alkene hydrogenation can be useful, as in the smooth reduction of alkylcinnamaldehydes (eq 4), the highly selective hydrogenation of methyl ( , )-octadeca-9,11-dienoate to methyl elaidate (eq 5), and of a range of polycyclic aromatics, e.g. naphthaeene (eq 6). 

Philippaerts A, Paulussen S, Turner S, Lebedev OI, Van Tendeloo G, Poehnan H, et al. Selectivity in sorption and hydrogenation of methyl oleate and elaidate on MFI zeolites. J Catal 2010 270 172-84. 

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