Phase fatty-ester synthesis

Lamare S, Legoy M (1993) Biocatalysis in the gas phase. TIBTECH 11 413 18 Laudani CG, Habulin M, Knez 2 et al. (2007) Lipase-catalyzed long chtiin fatty ester synthesis in dense carbon dioxide kinetics and thermodynamics. J Supercritical Fluids 41 92-101 Lauwers A, Scharpe S (1997) Pharmaceutical enzymes. Marcel Dekker, New York, 401 pp Laval JM, Thomas D, Mazeran PE (2000) Nanobiotechnology and its role in the development of new analytical devices. Analyst 125 29-3... 

Microwave heating and catalysis have been successfully used in the solvent-free synthesis of cosmetic fatty esters (Villa et al., 2003). Two kinds of reaction were performed acid-catalysed esterification (Figure 3.11) and phase-transfer catalysed alkylations, both reactions affording near quantitative yields when microwave heating was used. It should be noted that diethyl ether and water were used in the purification of the product, and alternative purification/separation procedures would be required if this process was performed on an industrial scale, due to the flammability risk of diethyl ether. 

Ganske F, Bomscheuer UT (2005) Optimization of lipase-catalyzed glucose fatty acid ester synthesis in a two-phase system containing ionic liquids and t-BuOH. J Mol Catal B Enzym 36 40 2... 

The solvent also influences the reaction through its effect on the relative soln-bility of substrate and product. Ideally, the substrate would be solubilized, while the insoluble product precipitates from solution. Thus, the recovery of product would be improved, thermodynamic equilibrium in the solvent phase would be driven toward ester synthesis, and product inhibition would be prevented. This scenario can occur for the lipase-catalyzed esterification of saccharides and nonpolar, saturated fatty acids. When employing polar solvents such as acetone, saccharides remain solubilized, while the product, saccharide-fatty acid monoester, precipitated. ... 

Ester formation is associated with yeast growth in the early phase of fermentation. Acetate esters are produced via the reaction between an alcohol and acetyl Co-A, which is catalysed by the enzyme alcohol acetyl transferases (ATFl and ATF2). Ethanol, branched-chain alcohols and 2-phenylethanol are the common moieties of acetate esters. Ethyl esters of medium-chain fatty adds are formed through the reaction between ethanol and respective fatty acyl Co-A, which is catalysed by the enzyme alcohol acyl transferases. Saccharomyces cerevisiae strains also produce esterases that hydrolyse esters, and thus the final concentration of esters in beers is the net balance between ester synthesis and hydrolysis. Strains of brewing yeasts produce predominantly ethyl esters of fatty acids, particularly ethyl octanoate, with relatively little formation of acetate esters. Ester production in beer is regulated by a number of factors such as yeast strain, temperature, hydrostatic pressure, wort composition, sugar type and concentration, type and amount of yeast-assimilable nitrogen, aeration, and unsaturated fatty acids (Hiralal, Olaniran, PiUay, 2014 Pires et al., 2014). 

Efficient enzymatic conversion can be achieved even though most of the reactants are present as solids, provided that there is a liquid phase in which the reaction can occur. This approach has been successfully used for carbohydrate ester synthesis with synthesis of glucose esters of fatty acids between C12 and C18 as typical examples [34]. It is important that the substrates dissolve during the reaction, and often the products precipitate as they are formed, which can be an advantage due to a favourable effect on the equilibrium position. Candida antarctica lipase B is an efficient catalyst in this system and solvents used (in moderate amounts) include ethyl methyl ketone, acetone or dioxane. In order to increase the ester yield, water formed in the reaction can be removed by azeotropic distillation and the solvent (e.g. ethyl metyl ketone) can after condensation be dried by pervaporation, giving a practically useful complete process [35]. 

Fell et al. presented a micellar two-phase system in which fatty acid esters can be hydroformylated [30]. Short fatty acids react in a mixture of water and the substrate without adding any surfactants. The rhodium/NaTPPTS catalyst system was able to conduct the reaction of methyl 10-undecenoate at 100°C with 30-bar synthesis gas pressure with a conversion of 99% without any surfactant. The reaction of linolenic acid ester was hindered by phase transfer problems which could be overcome by employing surfactants. The addition decreased the reaction time, so the same rhodium catalyst could achieve a conversion for linolenic methyl ester of 100%. The authors... 

Effect of Acyl Donors. TTie synthesis of glucose fatty acid esters was investigated with continuous by-product removal in a stirred-tank membrane reactor by azeotropic distillation using EMK containing 20% hexane as reaction solvent and different fatty acids as acyl donors. From previous studies on the lipase-catalyzed synthesis of glucose esters in a solid-phase system (17,19,22,23), it was already known that the fatty acid chainlength had a considerable influence on product formation. This was due... 

Yan, Y., U.T. Bornscheuer, L. Cao, and R.D. Schmid, Lipase-Catalyzed Solid-Phase Synthesis of Sugar Fatty Acid Esters. Removal of By-Products by Azeotropic Distillation, Enzyme Microb. Technol. 25 725-728 (1999). 

Cao, L., Fischer, A., Bomscheuer, U. T., and Schmid, R. D., Lipase-catalyzed sohd phase synthesis of sugar fatty acid esters. Biocat. Biotrans., 14 269-283, 1997. 

The synthesis of [ C]-labeled esters using a C-alkylation of diethyl malonate under microwave-enhanced solid-liquid phase transfer catalysis (PTC) conditions and a subsequent microwave-enhanced decarboalkoxylation (Krapcho reaction) [167] indicates that an alternative approach to the preparation of [ C]-labeled fatty acids/esters [168] with less harsh conditions may be possible. 

Cao L, Eischer A, Bornscheuer UT et al. (1997) Lipase-catalysed solid phase synthesis of sugar fatty acid esters. Biocatal Biotransfor 14 269-283 Cao L, van Langen L, Sheldon, R (2(X)3) Immobilised enzymes carrier-bound or carrier-free Curr Opin Biotechnol 14 1-8... 

The synthesis of fatty acid amide ethoxyiates can be described in three steps (see Scheme 1). The first step concerns the preparation of fatty acid methyl esters. The fatty acid is heated in sulfuric acid in the presence of methanol. The lower phase of the resulting two-phase system then contains the fatty acid methyl ester. Second, the fatty acid methyl ester is reacted with mono-... 

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