Starch alkylation

Fully alkylated starches are insoluble in water but are soluble in many polar nonaqueous and nonpolar solvents. Starch alkylated to a lower extent retains its water solubility but is also soluble in alcohols and chloroform. The solutions have a micellar character.741 Decrease in the softening points of alkyl starch ethers as the length of the alkyl chains increased is observed.706 The solubility of etherified starches depends also on which etherifying agent is applied. 

Alkylated starch can be fragmented by acetolysis into water soluble tri- and tetra-saccharides.742 Formic acid, together with a small amount of acetyl chloride, may be used instead.743 Alkyl a-D-glucosides can be prepared by treating starch with hydrogen chloride a solution of hydrochloride in a simple alcohol.744... 

Cationic Starches. The two general categories of commercial cationic starches are tertiary and quaternary aminoalkyl ethers. Tertiary aminoalkyl ethers are prepared by treating an alkaline starch dispersion with a tertiary amine containing a P-halogenated alkyl, 3-chloto-2-hydtoxyptopyl radical, or a 2,3-epoxypropyl group. Under these reaction conditions, starch ethers are formed that contain tertiary amine free bases. Treatment with acid easily produces the cationic form. Amines used in this reaction include 2-dimethylaminoethyl chloride, 2-diethylaminoethyl chloride, and A/-(2,3-epoxypropyl) diethylamine. Commercial preparation of low DS derivatives employ reaction times of 6—12 h at 40—45°C for complete reaction. The final product is filtered, washed, and dried. 

Quaternary ammonium alkyl ethers are prepared similarly an alkaline starch is reacted with a quaternary ammonium salt containing a 3-chloto-2-hydtoxyptopyl or 2,3-epoxyptopyl radical. Alternatively, such derivatives can be prepared by simple quaternization of tertiary aminoalkyl ethers by reaction with methyl iodide. Sulfonium (107) and phosphonium (108) starch salts have also been prepared and investigated. Further work has explained the synthesis of diethyl aminoethyl starch (109) as well as the production of cationic starches from the reaction of alkaline starch with... 

Quaternary ammonium compounds (quats) are prepared - by moderate heating of the amine and the alkyl halide in a suitable solvent - as the chlorides or the bromides. Subsequently conversion to the hydroxides may be carried out. Major applications of the quat chlorides are as fabric softeners and as starch cationizing agent. Several bio-active compounds (agrochemicals, pharmaceuticals) possess the quat-structure. Important applications of quat bromides are in phase transfer catalysis and in zeolite synthesis. 

Carboxymethylcellulose, polyethylene glycol Combination of a cellulose ether with clay Amide-modified carboxyl-containing polysaccharide Sodium aluminate and magnesium oxide Thermally stable hydroxyethylcellulose 30% ammonium or sodium thiosulfate and 20% hydroxyethylcellulose (HEC) Acrylic acid copolymer and oxyalkylene with hydrophobic group Copolymers acrylamide-acrylate and vinyl sulfonate-vinylamide Cationic polygalactomannans and anionic xanthan gum Copolymer from vinyl urethanes and acrylic acid or alkyl acrylates 2-Nitroalkyl ether-modified starch Polymer of glucuronic acid... 

Used in metal treating/cleaning operations, petroleum well activation, refining ore in the production of tin and tantalum, hydrolyzing of starch and proteins in production of various foods, in the production synthetic rubber, vinyl chloride and alkyl chlorides and in the manufacture of fertilizers, dyes and dyestuffs, artificial silk and pigments for paints. 

Alkyl polyglucosides (APG) and alkyl glucamides (AG) are non-ionic surfactants produced on the basis of renewable feedstocks such as glucose and fatty alcohols, which are derived from starch and palm oil, respectively. 

This starch derivative is a water-soluble polymer of D-glucose with a largely helical structure. Therefore, like cyclodextrins, it has the ability to bind alkyl chains and to catalyse reactions through the involvement of ionized hydroxyl groups in basic solution (Hui et al., 1982 Cheng et al., 1985). 

Alkyl polyglycosides have long been known but only now, following several years research, has it been possible to develop reaction conditions that allow manufacture on a commercial scale. The structure on which these compounds are based corresponds exactly to the surfactant model described above. The hydro-phobic (or lipophilic) hydrocarbon chain is formed by a fatty alcohol (dodecanol/ tetradecanol) obtained from palm kernel oil or coconut oil. The hydrophilic part of the molecule is based on glucose (dextrose) obtained from starch (Fig. 4.14). 

CA 66, 39497e(1967) An aerated aqueous expl compn of improved sensitivity and regulated d and expl strength was provided by passing compressed air into a slurry contg 20—75% oxidizer (such as nitrates and perchlorates of NHa, K, Na, Ca, Ba, etc), 4—35% water, 4—60% sensitizer (such as TNT, Pentolite, PETN, smokeless propint, RDX or Tetryl ),A1 and Mg, 0.5—2.0% thickener (such as gaar gum, CM-cellulose starch), 0.6—5.0% surfactant [such as diethano lam ides of coconut lauric acids, triethanolamine salts, alkyl-poly (oxyethylene)s, arylalkylsulfonates mixed dimethylamine oxides]. Presence of... 

Starch Ethers. A large number of starch ethers have been prepared and patented only a few are manufactured and used commercially. Commercially available starch ethers are the hydroxy alkyl ethers, hydroxyethylstarch [9005-27-0] and hydroxypropylstarch [9049-76-7], and cationic starches. 

Aqua, ammonium lactate, aluminium starch octenylsuccinate, C12-15 alkyl benzoate, isopropyl palmitate, polymethyl... 

Research had confirmed that no parent simazine residues were found in treated com plants, and additional data on the dissipation pathway of simazine needed to be developed. Research also indicated that triazines interfered with the photosynthetic process on susceptible growing weeds, as evidenced by the appearance of chlorotic leaves. Steps were undertaken to elucidate simazine s dissipation pathway and herbicidal mode of action. In Basel, Dr. Gast (1958) showed that the accumulation of starch by common coleus (Coleus blumei Benth.) plants was inhibited from treatment with 2-chloro-4,6-bis-(alkyl-amino)-triazines due to the inhibition of sugar synthesis. At the same time, Moreland et al. (1958) found weed control activity could be reduced by supplying carbohydrates to the plants through their leaves and that simazine was a strong inhibitor of the Hill reaction in photosynthesis. Exer (1958) found that triazines inhibited the Hill reaction as strongly as urea of the CMU (monuron) type. 

Starch is an abundant, inexpensive polysaccharide that is readily available from staple crops such as com or maize and is thus is mostly important as food. Industrially, starch is also widely used in papermaking, the production of adhesives or as additives in plastics. For a number of these applications, it is desirable to chemically modify the starch to increase its hydrophobicity. Starch modification can thus prevent retrodegradation improve gel texture, clarity and sheen improve film formation and stabilize emulsions [108], This may, for example, be achieved by partial acetylation, alkyl siliconation or esterification however, these methods typically require environmentally unfriendly stoichiometric reagents and produce waste. Catalytic modification, such as the palladium-catalyzed telomerization (Scheme 18), of starch may provide a green atom-efficient way for creating chemically modified starches. The physicochemical properties of thus modified starches are discussed by Bouquillon et al. [22]. 

Free radicals originating from starch, amylose, and amylopectin form well-distinguished 1 3 1 or 1 4 1 triplets showing hyperfine splitting of 30 gauss. These triplets are attributed to the derivatives of alkyl radicals produced by abstraction of hydrogen atoms from the 2-, 3-, and/or 4-positions of glucose residues.269... 

Granular starch and copolymers of ethylene and acrylic esters and alkyl(meth)acr-ylates or vinylacetate are produced as master batches for the production of mulch films, geotextiles and molded articles.146 The polar copolymers act as compatibilizers by lowering the interfacial energy between starch and the polyolefin and eliminate the need to coat granules. Processing via a vented twin-screw extruder also eliminates the need for anhydrous starch. 

The hydrophilic part of the alkyl polyglucoside is derived from a carbohydrate source, and raw material costs increase in the order starch/glucose syrup/glucose monohydrate/water free glucose while plant equipment requirements and hence cost decrease in the same order. 

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