Fatty acid alkyl esters

Mixtures of triglycerides, triglycerides plus free fatty adds or triglycerides plus fatty acid alkyl esters are used as reactants in fat modification processes. These mixtures are exposed to lipases supported on macroporous particles in the presence of a small amount of water. Liquid substrates (oils) can be reacted without use of a solvent, but with solid reactants (fats) it is necessary to add a solvent to ensure that the reactants and products are completely dissolved in the organic phase. Various water immisdble solvents can be used, but hexane is preferred for commercial operation because this solvent is already used industrially for the processing of oils and fats. 

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]. 

TABLE 1 CMC of Different Sodium a-Sulfo Fatty Acid Alkyl Esters... 

Salts of a-sulfo fatty acid esters can work as emulsifying agents for the preparation of asphalt emulsions and asphalt-latex emulsions. The ester sulfonates improve the storage stability of the emulsions [101,102]. In the manufacture of lightweight gypsum products air bubbles have to be mixed into the slurries. The use of salts of sulfonated C10 l8 fatty acid alkyl esters as foaming agents produces uniformly distributed fine bubbles [103]. Salts of C10 16 fatty acid alkyl ester sulfonates can also be added to cement mixtures to prevent slump loss of the mixtures [104]. 

Vegetable oil-based inks today offered in Germany are mainly for the heatset printing colours cyan, magenta, yellow and to a lesser extent black. The use of fatty acid alkyl esters as high-boiling solvents in offset inks as substitution of mineral oils is also practised [23]. 

Triglycerides are nontoxic, biodegradable and renewable molecules which are being used as substrate for the synthesis of a variety of useful molecules such as glycerol esters, fatty acid alkyl esters, triacetin, ketals, acetals, glycerol carbonates, etc (Scheme 1). 

The desire to minimize this competitive oligomerization has motivated research into alternative means to decrease the polydispersity and simultaneously increase the molecular weight of the seed-oil derived polyols. Recent patents [128, 129] investigate an approach previously demonstrated for the hydroformylated polyols [130-132], i.e., hydroxylation of the fatty acid alkyl ester followed by polymerization from a petrochemically derived initiator molecule. Inventors state that this approach provides an improvement over previous epoxidized/hydroxylated polyols by allowing better control of the molecular weight and the functionality of the polyol products. 

This reaction offers several advantages when compared to esterification of fatty acids, mainly owing to the possibility of using vegetable oils as substrates. In this case, a vegetable oil and an alcohol are used as substrates in the production of glycerol and fatty acid alkyl esters. Conventionally, acid and basic catalysts have been used (4,5). However, the use of acid catalysts usually results in low conversions. The use of basic catalysts require the utilization of vegetable oils with low free fatty acid con-... 

Index Entries Supercritical alcohol biodiesel fatty acids alkyl ester transesterification alkyl esterification. 

Figure 2 shows changes in the yields of fatty acid alkyl esters treated in the batch-type reaction system with various supercritical alcohols at 350°C. In the case of methanol, >90% yield of methyl esters was achieved... 

These results demonstrate that the yields of fatty acid alkyl esters were not significantly different when rapeseed oil was treated in the batch-type system with ethanol, 1-propanol, and 1-butanol at 350°C. 

Fig. 4. Effect of reaction pressure on yield of fatty acid alkyl esters of rapeseed oil treated with various supercritical alcohols at 300°C for 20 min in flow-type reaction system.

Fig. 5. Changes in yields of fatty acid alkyl esters from various fatty acids treated with supercritical alcohols at 300°C in batch-type reaction system.

TABLE 1.1. Cetane number (CN) of biodiesel and selected fatty acid alkyl esters. 

Bournay, L., and Baudot, A. 2006. Process for the production of fatty acid alkyl esters and glycerol of high purity. Eur. Patent 1616853. 

Lara, P. V., and Park, E. Y. 2004. Potential application of waste activated bleaching earth on the production of fatty acid alkyl esters using Candida cylindracea lipase in organic solvent system. Enzyme and Microb. Technol., 34, 270-277. 

The sulphonates derived from fatty acid alkyl esters (mainly, as sodium salts of a-sulphomonocarboxylic esters or, in other words, methyl ester sulphonates) become more and more attractive in view of their renewable raw material sources, such as triglycerides of animal and vegetable origin. Fatty acid alkyl esters are produced via a direct transesterification of triglycerides with alcohol, typically methanol, or via direct esterification of fatty acids. The same thin-film sulphonation techniques (see Table 1.5) with gaseous SO3 are used today to manufacture these surfactants [62, 70]. The two-step sulphonation can be represented by the sequential reactions [70, 71] shown in Fig. 1.4. 

Biodiesel is typically produced by chemical synthesis from triacylglyc-erols (TAGs) to produce fatty acid alkyl esters (FAAE). However, FAAEs and fatty alcohols have also been produced directly from sugars in E. coli up to 700 mg 1-1 [110]. 

Transesterification of vegetable oils or animal fats with methanol is the conventional method for BDF production a triglyceride molecule reacts with three molecules of a short-chain alcohol in the presence of a catalyst to form three fatty acid alkyl esters and a glycerol molecule as represented in Scheme 6.29. Although different types of short-chain alcohols such as methanol, propanol, and butanol can be used for the transesterification, methanol is most widely applied because of its... 

Transesterification of triglycerides can be facilitated by both Br0nsted acid and base catalysts [204, 205]. Essential steps over each catalyst types are shown in Scheme 6.30 and Scheme 6.31, respectively. Reaction over acid catalysts first requires triglyceride adsorption, whereas the reaction over base catalysts is initiated by alcohol adsorption. Thereafter, the carbonyl moiety in the glyceride molecule is attacked to produce the alkyl esters. These steps occur consecutively to form the diglyceride and monoglyceride esters, with three molecules of fatty acid alkyl esters produced for every molecule of glycerol. 

Pi, R. S. and Bigorra, J. L., Process for preparation of alkoxylated fatty acid alkyl esters, German Patent DE 19611508 Cl, to Henkel KGaA (1997) Chem. Abstr., 127, 137366. 

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