Sucrose fatty acid methyl ester with

Sorbitol is the most important higher polyol used in direct esterification of fatty acids. Esters of sorbitans and sorbitans modified with ethylene oxide are extensively used as surface-active agents. Interesteritication of fatty acid methyl esters with sucrose yields biodegradable detergents, and with starch yields thermoplastic polymers (36). 

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. 

Parrish (1977) reviewed the research and development of lactose ester-type surfactants carried out by Scholnick and his colleagues (Scholnick et al. 1974, 1975 Scholnick and Linfield 1977). Their initial attempts to form lactose esters followed the same transesterification procedures that had been used with sucrose (a fatty acid methyl ester in N,N-dimethylformamide with potassium carbonate as the catalyst). Their successful approach was the reaction of lactose in N-methyl-2-pyrrolidone as the solvent with fatty acid chlorides, resulting in yields of 88 to 95% for esters of lauric, myristic, palmitic, stearic, oleic, and tallow fatty acids. The principal product was the monoester, which is important for detergent use, since diesters and higher esters of lactose are not water soluble. 

Olestra occurs as a solid, soft gel, or liquid at room temperature depending on the fatty acids used in manufacture. It is a mixture of the octa-, hepta-, and hexa-esters of sucrose prepared by the reaction of sucrose with edible C12 to C20 and higher fatty acid methyl esters. It is insoluble in water and soluble in common lipid solvents. 

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... 

The primary site of esterification of sucrose with fatty acid methyl esters is the sixth position on the glucose unit of the sucrose molecule. Commercial products contain, however, a mixture of sucrose mono-, di- and tri-esters. 

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]. 

They are obtained, among other methods, by transesterification of fatty acid methyl esters (14 0, 16 0, 18 0 and/or 18 1, double bond position 9) with sucrose and lactose. The resultant mono- and diesters are odorless and tasteless. Depending on their structure, they cover an HLBrange of 7-13, and are used in stabilization of o/w emulsions, or in stabilization of some instant dehydrated and powdered foods. 

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). 

Derivatisation of inulin with unsaturated fatty acid methyl esters or oils results directly in products with alkyd type characteristics. In order to synthesise oligomers from sucrose, the addition of renewable dicarboxylic acids (or polycarboxylic acids) is also required along with sucrose and fatty acid methyl esters. Examples of such renewable dicarboxylic acids are dimethyl succinate and dimethyl sebacate. 

Scheme 4.2 Synthesis of sucrose esters by base-catalysed trans-esterification with fatty acid methyl esters (R COOMe), usually carried out in solvents (e.g. dimethyl formamide), microemulsions or solvent free.

Figure 4.4 Mass balance of reagents and products in the esterification of sucrose with fatty acid methyl ester under solvent- and water-free conditions (125°C, K2CO3, sucrose ester as emulsifier).

Bioethanol (mainly from sucrose and starchy crops) and biodiesel production (via transesterihcation of triglycerides) are the main first-generation biofuels that are currently produced on industrial scale. Biodiesel is produced by transesterihcation of triacylglycerols with short-chain alcohols (mainly methanol or ethanol) to produce monoalkyl esters, namely fatty acid methyl esters (FAMEs) and fatty acid ethyl esters (FAEEs). The worldwide production of biodiesel is mainly dependent on the utilization of waste oils, animal fats, and oilseeds such as rapeseed, sunflower, and soybeans. The recent food crisis has shown that research should focus on the development of second-generation biofuels generated from lignocellulosic raw materials and industrial waste streams (eg, food industry wastes). 

Aside of the important - fatty acid methyl esters and the various - glyeerides, there are wax esters (- waxes), - sorbitol esters, - sucrose fatty acid esters, ester oils (- lubricants) and various esters of natural hydroxy acids with mono/diglycerides. Some other f. of significance include ... 

Sucrose fatty acid polyesters, e.g., sucrose octapalmltate, have been synthesized in high yield by alkali metal catalysed transesterlflcat-lon of sucrose octaacetate with the appropriate methyl esters of the fatty acid in the absence of solvents. Dithlocarbonatlon of sucrose in sodium hydroxide-pyridine, which allows product acetylation without isolation, has been achieved using carbon disulphide. Chromatography yielded an anticipated range of partially xanthated, otherwise acetylated sucrose derivatives In pure form. 6,6 -Dl-0-... 

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. 

Olestra is prepared by a solvenfless transesterification process in which sucrose is treated with methyl ester of fatty acids in the presence of sodium methoxide between 100—180°C for 14 hours (68). The manufacturing process involves removal of the unreacted fatty acid esters by enzymic hydrolysis... 

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. 

Sucrose fatty esters could be prepared by reacting sucrose with fatty acid esters (interesterification) in a solvent (DMF, DMSO) or emulsion process (propylene glycol). Most interesting - because it avoids hazardous solvents - is the melt process where sucrose and the fatty acid ester (e.g. methyl) are reacted together without any solvent. ... 

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. 

In 1967 Dr. Osipow and coworkers developed the Nebraska-Snell process, in which a microemulsion of sucrose is formed in a propylene glycol solvent and treated with methyl esters of fatty acids. This method was then improved in Japan by Daiichi Kogyo Seiyaku Co., Ltd., who succeeded in industrializing it by using water instead of propylene glycol. 

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). 

Synthesis was carried out on a laboratory (up to 500g) scale by transesterifying sucrose at 90° - 100°C and 30 mm under nitrogen with three to five molar proportions of methyl fatty esters (acid value preferably less than 1 mg KOH/g) in dimethylsulphoxide (DMSO) (about 30 - 35% of the total reactants) and about 0.5 to preferably not greater than 2% dry weight of anhydrous potassium carbonate on the weight of methyl esters. Low amounts of catalyst and low acid values reduce contamination of the product with potassium soap. 

The presence of potassium soaps in resins synthesised from crude sucrose esters had an adverse effect on the water resistance of air-dried films. The gloss of paints also was reduced. Improved performance was noted using soap-free sucrose esters or, particularly, the products obtained by extraction of these materials with methanol to remove the more hydrophilic mono- and disubstituted sucrose esters, free fatty acids emd unreacted methyl esters. 

SCHEME 1 Ryoto sugar ester synthesis is based on transesteriiication of sucrose with a methyl fatty acid ester under conditions in which methanol is continuously removed. The product includes a complex mixture of K-soaps, diesters and mono-/ diglycerides, as well as the sucrose monoester when produced from crude beef tallow. An excess of sucrose is required (3 mol) to enhance the yield of the monoester over higher substituted products. DMF must be recovered for economic operation and because of its toxicity. 

---