Triglycerides transesterification

C=C bonds) that can be used as platform molecules, as well as glycerol, which is a co-product of triglycerides transesterification. 

Methanol and Triglycerides. Transesterification of triglycerides in methanol using HCIO4 is hazardous.18... 

Figure 3. Triglycerides transesterification reaction with ethyl alcohol.

Suwannakarn, K., Loreto, E., Ngaosuwan, K. and Goodwin Jr., J.G. 2009. Simultaneous free fatty acid esterification and triglyceride transesterification using a solid acid catalyst with in situ removal of water and unreacted methanol. Ind. Eng. Chem. Res. 48 2810-2818. 

Alonso, D. M., Mariscal, R., Moreno-Tost, R., Zafra Poves, M.D., Lopez Granados, M. Potassium leaching during triglyceride transesterification using K/A1203 catalysts. Catal Comm 8,2074—2080 (2007). 

Reproduced from Wilson, K., et al., 2008. The application of calcined natural dolomitic rock as a solid base catalyst in triglyceride transesterification for biodiesel synthesis. Green Chemistry, 654—659. Available at http //dx.doi.org/10.1039/b800455b with permission from The Royal Society of Chemistry. 

Adapted from Woodford, J.J., et al., 2014. Identifying the active phase in Cs-promoted MgO nanocatalysts for triglyceride transesterification. Journal of Chemical Technology and Biotechnology 89(1), 73—80 with permission from the John Wiley and Sons. 

Figure 7.2 Reaction Scheme of triglycerides transesterification with methanol (methanolysis) through chemical catalysis (base or acid).

RandomiZation/Interesterification. Transesterification occurs when a carboxyUc acid (acidolysis) or alcohol (alcoholysis) reacts with an ester to produce a different ester (20). Ester—ester interchange is also a form of transesterification. If completely unsaturated triglyceride oil (UUU) reacts with a totally saturated fat (SSS) in the presence of an active catalyst such as sodium, potassium, or sodium alkoxide, triglycerides of intermediate composition may be formed. 

Oils are mixtures of mixed esters with different fatty acids distributed among the ester molecules. Generally, identification of specific esters is not attempted instead the oils are characterized by analysis of the fatty acid composition (8,9). The principal methods have been gas—Hquid and high performance Hquid chromatographic separation of the methyl esters of the fatty acids obtained by transesterification of the oils. Mass spectrometry and nmr are used to identify the individual esters. It has been reported that the free fatty acids obtained by hydrolysis can be separated with equal accuracy by high performance Hquid chromatography (10). A review of the identification and deterrnination of the various mixed triglycerides is available (11). 

Compared with the fatty alcohol sulfates, which are also oleochemically produced anionic surfactants, the ester sulfonates have the advantage that their raw materials are on a low and therefore cost-effective level of fat refinement. The ester sulfonates are produced directly from the fatty acid esters by sulfona-tion, whereas the fatty alcohols, which are the source materials of the fatty alcohol sulfates, have to be formed by the catalytic high-pressure hydrogenation of fatty acids esters [9]. The fatty acid esters are obtained directly from the fats and oils by transesterification of the triglycerides with alcohols [10]. 

The starting substances for the production of a-ester sulfonates are the triglycerides of animal and vegetable fats and oils. The transesterification of the glycerides with alcohol leads directly to fatty acid alkyl esters and glycerin [7]. 

For technical applications, the production of ester sulfonates from the (purified) sulfo fatty acids involves too much effort, especially because the relevant fatty acid esters can be produced directly from the triglycerides of fats and oils by transesterification. The only possible way to produce ester sulfonates is the sulfonation of fatty acid esters. 

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). 

Chemoenzymatic synthesis of alkyds (oil-based polyester resins) was demonstrated. PPL-catalyzed transesterification of triglycerides with an excess of 1,4-cyclohexanedimethanol mainly produced 2-monoglycerides, followed by thermal polymerization with phthalic anhydride to give the alkyd resins with molecular weight of several thousands. The reaction of the enzymatically obtained alcoholysis product with toluene diisocyanate produced the alkyd-urethane. 

Biodiesel is a fuel derived from renewable natural resources such as soybean and rapeseed and consists of alkyl esters derived from transesterification of triglycerides with methanol. In spite of all the advantages of biodiesel, such as low emissiotts, biodegradability, non-toxicity, and lubricity, the major hurdle in penetration of biodiesel is its high cost because of the expensive food grade refined vegetable oil feedstock. 

Attention is drawn to the hazards involved in the use of perchloric acid in a published method [1] for transesterification of triglycerides with methanol. Alternative acid catalysts and safety precautions are suggested [2],... 

The rates of transesterification of triglycerides to methyl esters, efficiently catalyzed by boron carbide (B4C), were, on the other hand, faster under microwave conditions, probably because of superheating of the boron carbide catalyst, which is known to be a very strong absorber of microwaves [40], Scheme 10.3. Yields of methyl ester of up to 98% were achieved. 

Transesterification of triglycerides in the presence of B4C [40]. The rate enhancement was not assessed quantitatively. Reaction conditions a stirred multi-mode tank reactor, no solvent. 

Starch and fatty acids are the main food constituents of biomass. Sugar is derived from starch by hydrolysis or directly by extraction from sugar cane or beet. Fermentation converts sugars into alcohol that can be directly used as fuel, or in principle can be used as the raw material of a bioreftnery plant for further upgrading. Triglycerides, derived from oil seeds, are used to be converted into biodiesel through transesterification processes (Fig. 1.14). 

Fatty Acid Esters and Fatty Alcohols Fatty acid esters are obtained by transesterification of triglycerides (vegetable oils) or by esterification of fatty acid with alcohol or polyols. Fatty alcohols are obtained by hydrogenation of esters on metal catalysts. Fatty acid esters and fatty alcohols are useful platform molecules to prepare surfactants, emulsifier, lubricants and polymers. 

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