Starch acetate derivative

Wacker, in which Hoechst had been a partner from the start, also managed to retain its independence, although it was still active in some commodity-type products (acetic acid, vinyl monomers and polymers, and silicon carbide), it chose to emphasize lines that showed greater profitability, such as silicones, hyper pure silicon for semiconductors, and specialty and fine chemicals. In France the well-run starch and derivatives producer Roquette Freres, after a short flirtation with Rhone-Poulenc, was able to recover its autonomy. 

The preparation of the first starch acetate, as well as the first cellulose acetate, was announced by SchUtzenberger in 1865. These acetates were prepared by heating the carbohydrates in acetic anhydride to about 140-160 . Further examination of this reaction has been made by Traquair who found that on heating starch to 90° with acetic anhydride a derivative of low acetyl content (1-4%) is obtained which is capable of forming clear, somewhat elastic films. This starch acetate, termed Feculose, was produced commercially for a time, being sold for use as a thickening agent and as a size for textiles and paper. 

C, whereas the com starch derivative only turned brown at this temperature. Further allylation led to diallyl ethers.748-752 For this purpose, an acetone solution of starch acetate in a 50% solution of NaOH containing allyl bromide was boiled or heated in an autoclave at 80 °C. These procedures were then improved by using either butanone and KOFI753 or 1,4-dioxane and NaOH.754 Di-O-allyIstarch is a soft, gummy product that is soluble in most of organic solvents except for aliphatic hydrocarbons. This solubility is lost after exposure of diallyl starch to air.748 It can also be hardened by the addition Co(II) octanoate or Co(II) naphthenate.755... 

The development of waxy corn species offered better potentials for the production of starch derivatives in high demand in the world market. The technology for the production of waxy starch-acetate has been elaborated. 

The reaction of polysaccharides ivith aldehydes to give cross-linked products has been known and exploited industrially for some time. Starch acetals may also be prepared by a method that does not give rise to cross-links and involves treatment of starch with a cyclic vinyl ether, 3,4-dihydro-2H-pyran, to give a tetrahydropyran-2-yl derivative (16). At low levels of substitution, the acetals are water-soluble, at... 

Methyl-, hydroxyethyl-, hydroxypropyl-, and carboxymethyl starches, starch acetates, succinates, alkenyl succinates (Fig. 2), adipates, and phosphates, are all well-known products. Furthermore, special derivatives have also been prepared, such as vinyl-, silyl-, ° or propargyl starches, as reactive intermediates for fiirther fime-tionalization. Unusual substitution patterns can also be established by highly selective deacetylation with alkyldiamines and subsequent introduction of such functional groups as sulfates. From die analytical point of view, the most important aspects are stability under alkaline (mediylation) and acidic or Lewis-acidic (depolymerization) conditions, reactivity (such as migration, rearrangement, further substitution or addition reactions, or any intramolecular reaction), and polarity (lipophilic/hydrophilic, ionic/nonionic, acidic/basic). These properties mainly determine the analytical... 

To recover the starch, the corn kernels, for example, are pealed and then dipped in sulfuric acid at pH 3.5-4 for 40 h at 125°C. The corn kernels softened in this way are then coarsely ground and the corn nucleus removed by floatation, whereby the starch particles sedimentate. Fiber components are filtered off and the starch particles are removed from the remaining protein solution by centrifugation. The recovered starch particles are then washed and dried. Sixty percent of the starch is converted to starch syrup or dextroses by partial hydrolysis. The remaining 40% is used in the food industry or in the textile, paper, or detergent industry, partially as derivatives such as starch acetate or hydroxyethyl starch. 

Staple fibers contain many loose and broken ends which can be maintained low for weaving by what is known as sizing. The cheq>est and most effective sizing material is starch. However, starch must be used in relatively large amounts. In addition, it gels and so, produces high viscosities. As well as this, it can only be removed by enzymatic treatment. For these reasons, starch derivatives such as starch acetate or hydroxyethyl starch are now also used. 

Starch acetates are one of the more common derivatives of starch and are made from starches with a variety of different amylose to amylopectin ratios. The reaction differs from other substituted starches in that it is begun with a neutral water starch slimy (pH 7 to 8), which is then blended with acetic anhydride [Figure 14] (34), acetic acid (35), vinyl acetate (36), or a number of other acetyl donating reagents (37,38,39). 

Starch/cellulose derivative systems are also reported in other publications (137,141,149,150), particularly, cellulose acetate and butyrate/starch blends in presence of glycerol and epoxidized soybean oil (149). 

Semi- synthetic Starch derivatives Hetastarch, starch acetate. Starch phosphate... 

Mater-Bi Corn starch/PBAT or acetate derivatives Novamontwww.biobagusa.com/mater bihtm Industrial compost... 

Starch Derivatives. The most important ester is starch acetate it is obtained according to the same method as that leading to cellulose acetate. The gradual substitution of acetate groups for hydroxyls decreases the hydrophilic-ity of modified starch even at low degrees of modification, the hydrosolubility in hot water disappears and products with D.S.> 1.5 become soluble in organic solvents. 

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