Fatty acid methyl esters , liquid

Transesterification of fat triglycerides is the predominant method for manufacture of mixed fatty acid methyl esters, and direct esterification of fatty acids (FA) is practiced if very selective cuts of product, in general as an intermediate detergent range alcohol, are desired. Methyl cocoate is a mobile, oily liquid above 25 °C with a yellow tint and a characteristic fatty pungent odor. FAME sulfonation to FAMES is technically possible but been rarely applied up to now (1990) (Table 13). 

An exception to the above are fatty acid methyl esters, which, due to the reaction mechanism involving molecular rearrangements with excess S03, have to be sulfonated at a slightly higher mole ratio of S03 to methyl esters (namely, 1.15-1.20/L). Outside the reaction tubes, in the reactor jacket, cooling water is circulated to control the liquid-film temperature and removing the reaction heat. 

Polypropylene glycol, particulate hydrophobic silica, and a fatty acid methyl ester, or an olefin or linear paraffin as a liquid diluent, are proposed for well-stimulation jobs [357]. 

Biodiesel may be represented chemically as a mixture of fatty acid methyl esters. It is a naturally derived liquid fuel, produced from renewable somces which, in compliance with appropriate prescriptions, may be used in place of diesel fuel for both internal combustion engines and for producing heat in boilers. The advantages, especially environmental, which can potentially result from the widespread use of biodiesel, are manifold ... 

Baillet, A., Corbeau, L., Rafidson, R, and Ferrier, D., Separation of isomeric compounds by reversed-phase high-performance liquid chromatography using Ag+ complexation. Application to cis-trans fatty acid methyl esters and retinoic acid photoisomers, /. Chromatogr., 634, 251, 1993. 

Scheme 5.1-70 Cracking and isomerization of fatty acids and fatty acid methyl esters in chloroaluminate(lll) ionic liquids.

Sample preparation is probably the most important step in any analytical procedure. Poor preparation of lipid samples will only yield inferior or questionable results. Some commonly performed sample-preparation procedures for gas-liquid chromatographic (GC) analysis of fatty acids in food samples are introduced in this unit. Since the introduction of gas chromatography in the 1950s, significant progress has been made in fatty acid analysis of lipids however, fatty acid methyl esters (FAMEs) are still the most commonly used fatty acid derivative for routine analysis of food fatty acid composition. 

While silver ion liquid chromatography has been utilized to separate fatty acid methyl esters (FAMEs) by number of double bonds and by the configuration (cis/trans) of the double bonds [1-3], the lack of commercial HPLC silver ion columns has limited the impact of this technology. 

Therefore, of the 2 moles of ester-bound 3-OH-14 0 one is 3-0-acylated by tetradecanoic acid the other should carry a free 3-hydroxyl group. This latter assumption was proven to be correct by the following experiment. Lipid A was treated with t-butyldimethylsilylchloride, ester-bound fatty acids were trans-esterified by NaOCH3 and analysed by gas-liquid chromatography. Besides the other expected fatty acid methyl esters (12 0, 16 0, 3-OCH3-14 0) approximately 1 mole (per 2 moles glucosamine) of the t-butyldimethylsilylether of 3-hydroxytetradecanoic acid me-thylester could be identified (26). 

Figure 143. Distribution of fatty acid methyl esters (FAME), monoacylglycerols (MG), and diacylglycerols (DG) in a liquid injection field desorption ionization (LIFDI) mass spectrum of biodiesel (Schlichting et al., unpublished).

In homogeneous catalysis, the catalyst is in the same phase as the reactants and products. Here we will concentrate on homogeneous catalysis in the liquid phase. In the classic case, the reactant (also called the substrate) molecules and the catalyst are reacted in a solvent. For example, the transesterification of fatty acid triglycerides with methanol (Figure 1.10) is catalyzed by hydroxide (OH-) ions. This is an important process for making fatty acid methyl esters which are then used as biodiesel. 

Figure 4.2 GC/MS analysis of methyl esters prepared from a whole cell lipid extract of the YEpOLEX-HzPGDsI-transformed ole1 strain of S. cerevisiae total ion spectrum of fatty acid methyl esters resolved by capillary GLC. The culture was grown in liquid complete medium (YPD) at 30°C to a density of 2 x 107 cells/ml prior to extraction and methylation. The external mass standard nonadecanoic acid methyl ester (19 Me) was added to the cell pellet prior to extraction. Peaks corresponding to Z9-16 Me and Z9-18 Me reflect trace amounts of unsaturated fatty acids in the growth medium. (Reproduced with permission from Rosenfield et at, 2001. 2001 by Insect Biochemistry and Molecular Biology.)...

Fig. 4.3. Gas-liquid chromatograph of the total fatty acid methyl esters of Calliobolhrium verticillatum, temperature-programmed from ISO to 200°C at 2 deg. C/min. (After Beach et at., 1973.)...

Table 4.10. Fatty acids of Calliobothrium verticillatum and of its host, the dogfish Mustelus canis. Samples were saponified, their fatty acids were extracted and methylated, and the fatty acid methyl esters were characterised and quantified by gas-liquid chromatography. (Data from...

Arveldano, M. I., van Rollins, M., and Horrocks, L. A. (1983) Separation and quantitation of free fatty acid and fatty acid methyl esters by reverse phase high pressure liquid chromatography, J. Lipid Res. 24, 83-93. 

UCOME = used cooking oil methyl esters B/S = biodiesel/solvent mass ratio TBatii = bath coolant temperature (final step) Yield = mass ratio liquid fraction to starting material Sats = total concentration of saturated fatty acid methyl esters in liquid fraction (determined by GC). See Tables 1.2 and 1.3 for other abbreviations. 

Olestra occurs as a solid, soft gel, or liquid at room temperature depending on the fatty acids used in manufacture. It is a mixture of the octa-, hepta-, and hexa-esters of sucrose prepared by the reaction of sucrose with edible C12 to C20 and higher fatty acid methyl esters. It is insoluble in water and soluble in common lipid solvents. 

P = palmitic 0 = oleic S = stearic L = linoleic GLC = gas liquid chromatography HPLC = high-performance liquid chromatography. Corrected using GLC analysis of fatty acid methyl esters. 

Liquid fuels play a key role in modem lifestyles. Their liquid nature offers convenience in being transportable and easy to use. Diesel, spark-ignition and Jet engines are the result of this convenience. Unfortunately, the hydrocarbons, which play the major role as liquid fuel are finite, and upon combustion contribute to the accumulation of carbon dioxide in the atmosphere. It is not surprising that alternate renewable liquid fuels are receiving attention. These include ethanol, methanol, fatty acid methyl esters and fast pyrolysis oils. All can be produced from renewable resources. Ethanol may be formed by fermentation of sugars and thereby indirectly from cellulose and starches. Methanol can be produced from carbon monoxide and... 

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