Transesterification of sucrose

The transesterification of sucrose has been performed with a fatty acid ester of a volatile alcohol in the presence of an alkaline catalyst in a dipolar, aprotic solvent.142 The reaction of sucrose (293 mmoles) with methyl dodecanoate (293 mmoles) in A/,N-dimethylformamide in the presence of sodium methoxide in a pressure bomb for 8 h at 130° gave, after solvent extraction and crystallization, sucrose mono(dodecanoate) (m.p. 72-80° [a]D+52°) in 50% yield.142 Commercialization of these sucrose esters has so far been limited, in part because of the use of expensive solvents, and, in part, because solvent remaining in the product makes it unsuitable for use as a food emulsifier. In view of this situation, methods have been developed in which the use of toxic and expensive solvents has been avoided. 

V. Molinier, K. Wiesniewski, A. Bouchu, J. Fitremann, and Y. Queneau, Transesterification of sucrose in organic medium Study of acyl group migrations, J. Carbohydr. Chem., 22 (2003) 657-669. 

N. R. Pedersen, P. J. Hailing, L. H. Pedersen, R. Wimmer, R. Matthiesen, and O. R. Veltman, Efficient transesterification of sucrose catalysed by the metalloprotease thermolysin in dime-thylsulfoxide, FEBS Lett., 519 (2002) 181-184. 

A copolymer of this monomer with N,N melhylenebis (acrylamide) imbibed 100 times its weight of water. This swelling was not affected by sodium chloride in the water. Most super-slurpers swell less in the presence of dissolved salts. Thus, the new copolymer may be of use in collecting urine in diapers. Another polymeric hydrogel was made by polymerization of sucrose-l -acrylate using sucrose-6,1 -diacrylate (prepared by enzymatic transesterification of sucrose and vinyl acrylate) as the cross-linking agent.155... 

Sucrose esters are manufactured by transesterification of sucrose with fatty acid methyl esters in a suitable solvent system where both components are soluble, such as dimethylformamide or dimethyl-sulphoxide (Benson, 1967). The sucrose esters are purified by distillation and crystallization from e.g. ethyl acetate in order to remove the solvent completely. For food use the content of dimethylformamide must be less that 1 mg/kg. An alternative... 

Since then, there has been a growing demand for SE, mainly in the food industry, as a very safe product having as its raw materials sugar cuid natural edible fats, and as a near-natural surfactant. In 1967, there was completed a full-scale plant with a continuous process scaled-up to 1200 tons per year. This process, known as the Hass-Snell process,used dimethyl-formamide as the solvent for a transesterification of sucrose by the methyl esters of fatty acids to yield SE. 

Description. Surfactants of this class are better known as sugar esters or sucrose esters. The sucrose esters are obtained by transesterification of sucrose with fatty acid methyl esters or triglycerides, leaving methanol or glycerol as by-products, respectively- Mono- and diesters are the major products. Due to the steric effects,-primary hydroxyl groups are almost exclusively subject to esterification. Both types of esters exhibit the general properties of common nonionics (i.e., ethoxylated alcohols). 

P. Potier, A. Bouchu, G. Descotes, and Y. Queneau, Proteinase N-catalysed transesterifications in DMSO-water and DMF-water Preparation of sucrose methacrylate, Tetrahedron Lett., 41 (2000) 3597-3600. 

Figure 5.1 Transesterification activity of (a) 0.025 or (b) 0.3 mg of lipase BC co-lyophilized with different amounts of sucrose ( ), trehalose (x) and mannitol ( ). Activity was tested in toluene by measuring the rate of 1-...

Chromatographic batch reactors are employed to prepare instable reagents on the laboratory scale (Coca et al., 1993) and for the production of fine chemicals. These applications include the racemic resolution of amino acid esters (Kalbe et al., 1989), acid-catalyzed sucrose inversion (Lauer, 1980), production of dextran (Zafar and Barker, 1988) and saccharification of starch to maltose (Sarmidi and Barker, 1993a). Sardin et al. (1993) employed batch chromatographic reactors for different esterification reactions such as the esterification of acetic acid with ethanol and the transesterification of methylacetate. Falk and Seidel-Morgenstern (2002) have investigated the hydrolysis of methyl formate. 

Many carbohydrate-based fat substitutes are mixtures of sucrose esters formed by chemical transesterification or interesterification of sucrose with one to eight FAs. The class with six to eight FAs are called sucrose FA polyesters. These molecules are too large to be broken down by intestinal lipase enzymes and, for that reason, do not show any caloric value (Voragen, 1998). 

The original preparation of sucrose esters of fatty acids involves the transesterification of a triglyceride molecule with sucrose in the presence of a basic catalyst at 90°C in Af,Af-dimethylformamide (DMF) as solvent (Fig. 7.3) [4]. 

Fatty acid methyl esters are currently used in transesterification reactions with sucrose. The formation of methanol, which can be distilled off, drives the estalfication process in favour of the sucrose ester and improves yields. A solvent-less process using a slurry of sucrose and potassium carbonate in fatty acid methyl este or triglycaide oil at 130°C has been developed more recently [5]. 

Sugar-based fatty acid ester diols have also been prepared by transesterification of epoxidised oleates with methyl a-D-glucopyranoside and sucrose, followed by hydrolysis of the oxirane ring [57]. These fully bio-based monomers were polymerised with an aliphatic diisocyanate to produce PU whose structure could be oriented toward a linear architecture (when the sugar OH groups were not involved) or a network (if at least some of them participated in the polycondensation) by changing the solvent medium. 

Other food emulsifiers are made by transesterification of fatty acid methyl esters with poly glycerols, sorbitan, sucrose and stearoyl lactate (Figure 10.2). Sugar, sorbitan fatty esters and polyoxyethylene sorbitan esters are used to stabilize oil-in-water food emulsions. Optimum emulsification is achieved with combinations of emulsifiers. Margarines are made with a combination of monoglycerides and lecithin, and cake mixes with a mixture of monoglycerides and propylene glycol monoesters. 

Transesterification. Six to 30 moles of methyl or ethyl acetate, methyl caprinate, laurate, oleate, stearate or methacrylate was added to a DMF solution of one mole of sucrose chelate. The reaction mixtures were allowed to stand 3 h at 100° or 120°C and analyzed. 

Table X. Composition of transesterification products of sucrose chelates and alcoholates with ethyl acetate, methyl caprinate, laurate, stearate, oleate, and ethyl methacrylate in DMF, 3 h, 80°-120°C, mole-%.

Methyl fatty acid esters, by-products of the production of glycerol from fats, are readily available. Transesterification with sucrose, under conditions in which methanol is removed continuously, results in the equilibrium shifting towards complete reaction (13). 

A monoester of sucrose prepared from a pure fatty acid methyl ester by transesterification is a mixture of positional isomers (15-20). Each isomer could behave differently in bread. Data in Figure 4 show a dramatic example of how positional isomers function differently in breadmaking (2) ). L-Ascorbyl 6-palmi-tate is an excellent dough strengthener, which showed a +92 cc volume response above a no-shortening control loaf (905 cc). On the other hand, L ascorbyl 2-palmi-tate decreased loaf volume 165 cc below the control. 

Substitution of up to substantially 5 sucrose hydroxyl groups (presumably the 3 primary and 2 reactive secondary groups) is achieved fairly readily by reaction of a 1 5 mole ratio of sucrose and methyl ester using the standard transesterification method. This involves the use of an aprotic solvent, and "bone-dry" potassium carbonate as catalyst at about 100°C. Synthesis of hexa/heptaesters is more difficult and it becomes necessary to use a 100% excess of methyl esters to achieve a 90% conversion of sucrose. The unreacted esters are recovered by chromatography or methanol extraction. 

C30H56O12 608.765 Enzymically synthesised by a transesterification reaction of sucrose with methyl stearate. Used for similar purposes to Sucrapan P above. Mp 56-60°. Mg +36.2 (c, 1 in EtOH). Octakis(alkanoyl) Olestra [121854-29-3] Nondigestible fat substitute for low-calorie food. 

Figure 7.15 Scheme of transesterification of medium-chain-length PHA with sucrose using C. antarctica lipase B in an organic solvent mixture. 

Fatty acid polyesters have been prepared by the weU established method of transesterification in the presence of sodium metal from the peracetates of D-glucitol and trehalose, of methyl glucoside, methyl galactoside, octyl glucoside, and stachyose, and of sucrose. The process for formation and purification of sucrose polyesters has been optimised to furnish pure products in >99% yield. ... 

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