Transesterification of fats

The transesterification of fats and fatty oils by methanol into fatty acid methyl esters proceeds at 50-70°C without pressure. The deacidified fat is stirred for a short period with an excess of methanol and 0.1-0.5% caustic alkali as catalyst. On standing the reaction mixture separates forming a bottom layer of glycerin and a top layer 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). 

In addition to their transformation into linear alcohols by hydrogenation, methyl esters obtained in the transesterification of fats and oils can also be used as raw materials for sulfonation, yielding a family of derivatives known as methyl ester sulfonates (MES). These products are only significant in some southeast Asian markets, Japan and to a much lesser extent in other markets such as the US. 

Schuchardt, U. and Lopes, O.C. 1988. Tetramethyl-guanidine catalyzed transesterification of fats and oils A new method for rapid determination of their composition. JAOCS 65 1940-1941. 

Transesterification of fats or oils with medium-chain alcohols may increase CN, a parameter that can influence ignition quality and exhaust emissions (Klopfenstein, 1985). On the other hand, increased branching in saturated hydrocarbon chains also decreases CN. Two studies comparing isopropyl... 

Methyl Ester-Based Processes. The fatty methyl esters are produced predominantly by the transesterification of fats and oils with methanol in the presence of an alkaline catalyst under very mild reaction conditions.l5a,b They are used in the production of lauric-type (Cl2) alcohols. The short-chain fatty methyl esters (C8-Cl0), produced as by-products via the fractional distillation of crude lauric-type (coconut, palm kernel) methyl esters, are converted to fatty acids via acidic or alkaline hydrolysis (Fig. 36.12). The hydrolysis of short-chain fatty methyl esters by stream splitting or Twitchell-type processes is not very efficient because of unfavorable equilibrium constants.16a,b... 

Transesterification Processes. Transesterification of fats and oils is the most commonly used process for the manufacture of methyl esters, except in cases where methyl esters of specific fatty acids are needed. 

Transesterification of fats, typically with methanol, using sodium methoxide as a catalyst, to produce methyl esters and glycerol (7). 

Already there are a few examples of large-scale reactions under such conditions (Table 6.6). Although it is likely that some are demonstration projects at a pilot scale, the transesterification of fats (see Scheme 6.29) is now a commercial reality in the manufacture of cocoa butter substitutes (50) and of methylethyltetradecanoate (isopropylmyristate) (51). The former is a valuable food ingredient, while the latter is used as a bulking agent in the formulation of cosmetics. 

Fatty acid esters are generally obtained from the transesterification of fats and oils with a lower alcohol, e.g. methanol, along with glycerol. More than 90% of all oleochemical reactions (conversion into fatty alcohols and fatty amines) of fatty acid esters (or acids) are carried out at the carboxy functionality. However, transformation of unsaturated fatty acid esters by reactions of the carbon-carbon double bond, such as hydrogenation, epoxidation, ozonolysis, and dimerization, are becoming increasingly of industrial importance. Here we will discuss another catalytic reaction of the carbon-carbon double bond, viz. the olefin metathesis reaction, in which olefins are converted into new products via the rupture and reformation of carbon-carbon double bonds [2]. Metathesis of unsaturated fatty acid esters provides a convenient route to various chemical products in only a few reaction steps. 

The presence of a membrane in biodiesel production plays two main roles the first one is transesterification of fats and oils to produce biodiesel, and the second one is to separate impurities such as GLY, alcohol, and catalyst from the FAME product stream without using water, solvents acids, or absorbents. 

Matsuo, T., Sawamura, N., Hashimoto, Y. and Hasido, W. (1980) Producing a cocoa butter substitute by transesterification of fats and oils, UK Patent Application 2035A, Fuji Oil Company Ltd., Japan. 

Sawamura, N. (1988) Transesterification of fats and oils, in Enzyme Engineering 9. Annals of the New York Academy of Sciences, eds. H.W. Blanch and A.M. Klibanov, New York, pp. 266-269. 

Catalysts speed up chemical reactions in which they do not actually enter. They are typically used in small quantities. Raney nickel is used as a catalyst in hydrogenation of oils and sodium methoxide (sodium methanoate) in the transesterification of fats. Acids are used as catalysts in the production of certain modified starches. Catalysts also include the enzymes used as food additives, such as amylase (El 100), proteases (El 101, for example papain, bromelain and ficin), glucose oxidase (El 102), invertase (E1103) and lipases (El 104). 

The study of microbial production of 1,3-propanediol has an interesting history (reviewed by Biebl et al. 1999). It is one of the oldest fermentation products known and has been studied for over 100 years. For a number of years, interest in the fermentation was due to its potential as an outlet for surplus glycerol. Glycerol can be made via a chemical process, or it can be derived from various agricultural fats during the production of fatty acids and soaps. Increased availability of low-cost glycerol might be expected in the future, as it is a by-product of such processes as transesterification of fats for biodiesel production as well as the process for ethanol production by yeast. 

Biodiesel (fatty acid methyl ester) Vegetable oils from rape seed, palm oil, microalgae Transesterification of fats Cyanobacterial production of lipids... 

Warwel et al. applied catalytic methods of olefin chemistry to achieve polymer building blocks as well as polymers like functionalized polyolefins, polyesters, polyethers, polyamides as well as sugar-based surfactants [4]. The fundamental approach was the polymer synthesis based on unsaturated fatty acid methyl esters, which are available by industrially applied transesterification of fats and oils with methanol. In Figure 18 is reported a schematic representation of the potential of plant oil components in the preparation of different polymeric materials. 

Figure 33 Preparation of monoglycerides of fatty adds by (1) transesterification of fats with glycerol and (2) direct esterification from fatty acids, at elevated temperatures and in the presence of alkaline catalyst.

P. are made by - esterification of polyglyeerol with - fatty acids or by transesterification of - fats and oils with polyglycerol. 

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