Dextran, acetate esters

Reaction of carbohydrate with quaternary ammonium hydroxide Dextran acetate Ester derivative of dextran Dextran ether esters Mixed benzyl and butyl ethers... 

In contrast to the broad variety of applications of 1 - 4 and 1 3 linked glucans after reaction with (C2 to C4) carboxylic acid anhydrides and chlorides [159], the use of dextran esters of short chain aliphatic acids such as acetates or propionates is rather limited. According to the present knowledge, the commonly applied acetylation of polysaccharides with the acetic acid anhydrides or acetyl chlorides in the presence of triethylamine or pyridine as base does not lead to pure and soluble dextran acetate with significant DS values. In contrast, dextran propionates [160] and butyrates [161] can be... 

Deuterium-labelled glycogen, III, 246 Dextran, 2,3-dimethyl-D-gIucose from methylated, V, 161 Dextran acetate, II, 218 Dextran beers, IV, 333 Dextran esters, II, 218 Dextran ethers, II, 218 Dextran triacetate, II, 210, 212 Dextran tribenzoate, II, 210, 212 Dextrans... 

The preparations of dextran, and certain ethers and esters of dextran have been the subjects of about fifteen recent patents. The dextran (of L. mesenteroides or dextraniczim) may be precipitated first from the culture by the addition of ethanol or acetone, or the culture itself may be treated directly with the appropriate halide and sodium hydroxide in either a single stage or a two-stage procedure. The benzyl ether of dextran, formed by the reaction of dextran with benzyl chloride and sodium hydroxide at 75-185° for three to ten hours, is soluble in acetone and other solvents, and may be used in lacquers. Mixed ether and ester derivatives of dextran, e. g., benzyl and phthalate or butyl and benzoate, have been used for forming films, coatings or molded products. A preparation of dextran acetate has also been patented. ... 

PGIP, purified fi om P.vulgaris hypocotyls [11], was immobilized to the sensor ch via amine coupling. A continuous flow of HBS buffer (5 pl/min) was mantained over the sensor surface. The carboxylated dextran matrix of the sensor surface was first activated by a 6-min injection of a mixture of N-hydroxy-succinimide and N-ethyl-N - (3-diethylaminopropyl) carbodiimide, followed by a 7-min injection of PGIP (lOng/pl in 10 mM acetate, pH 5.0). Hie immobilization procedure was con leted by a 7-min injection of 1 M ethanolamine hydrochloride to block the remaining ester groups. 

Another potentially important fermentation is that producing butyric acid. The process is used industrially on only a small scale at present and details have not been disclosed. Many derivatives of butyric acid are used industrially the benzyl, methyl, octyl and terpenyl esters are used in the perfumery and essence trade and amyl butyrate, bornyl and isobornyl butyrates have been described as plasticizers for cellulose esters. Moreover vinyl butyrate is a possible ingredient of polymerizable materials. The mixed acetic and butyric acid esters of polysaccharides are also coming into favor. Cellulose acetate butyrate is marketed as an ingredient of lacquer and is less inflammable than the pure acetate. Dextran (see below) acetate butyrate may have similar uses. 

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. 

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