Hydroxypropyl starch ether

Waxy starch, hydroxypropyl ether Waxy starch, carboxymethyl ether Waxy starch acetic acid ester... 

Etherification. Carbohydrates are involved in ether formation, both intramoleculady and intermoleculady (1,13). The cycHc ether, 1,4-sorbitan, an 1,4-anhydroalditol, has already been mentioned. 3,6-Anhydro-a-D-galactopyranosyl units are principal monomer units of the carrageenans. Methyl, ethyl, carboxymethyl, hydroxyethyl, and hydroxypropyl ethers of cellulose (qv) are all commercial materials. The principal starch ethers are the hydroxyethyl and hydroxypropylethers (see Cellulose ethers Starch). 

Hydroxypropyl starch is a derivative of natural starch it is described in the JPE 2004 as a hydroxypropyl ether of corn starch. 

Hydroxypropyl ether of cellulose. See Hydroxypropyl cellulose Hydroxypropyl ether guar gum. See Hydroxypropyl guar Hydroxypropylglycerin Properties Pale straw-colored liq. sol. in water and methanol dens. 1.084 pour pt. -23 C flash pt. 193 C ref. index 1.459 Precaution Combustible Uses Intermediate for alkyd resins and polyesters plasticizer for cellulosics, glue, starch, etc. 

Synonyms HP starch Hydroxypropyl corn starch ether Starch, 2-hydroxypropyl ether... 

Hydroxypropyl ether [9049-76-7] Modified starch used as sizing agent and adhesive. 

Our objective was to prepare more hydrophobic starches to incorporate them in latex preparation for decorative paints so that substrates derived from fossil fuel can be replaced by modified starches derived from renewable resources. Partial substitution of starch with acetate, hydroxypropyl, alkylsiliconate or fatty-acid ester groups was described in the literature for the synthesis of more hydrophobic starch. An alternative route was employed consisting of grafting octadienyl chains by butadiene telomerization (8,9). This reaction (Figure 4) was catalyzed by hydrosoluble palladium-catalytic systems prepared from palladium diacetate and trisodium tris(m-sulfonatophenyOphosphine (TPPTS). Starch octadienyl ethers are expected to be much less sensitive towards hydrolysis compared to the esterified starches. 

Trade Names Klucel E Klucel EF Pharm Klucel EXF Pharm Klucel F Grades Klucel G, H, J, M Klucel GF Klucel HF Klucel HXF Klucel JF Klucel L Klucel LF Pharm Klucel MF Hydroxypropyl corn starch ether. See Hydroxypropyl starch Hydroxypropyl dIstarch phosphate CAS 53124-00-8 INS1442 E1442... 

Synonyms Starch, hydrogen phosphate, 2-hydroxypropyl ether Classification Modified starch... 

In industrial production of acid-modified starches, a 40% slurry of normal com starch or waxy maize starch is acidified with hydrochloric or sulfuric acid at 25—55°C. Reaction time is controlled by measuring loss of viscosity and may vary from 6 to 24 hs. For product reproducibiUty, it is necessary to strictly control the type of starch, its concentration, the type of acid and its concentration, the temperature, and time of reaction. Viscosity is plotted versus time, and when the desired amount of thinning is attained the mixture is neutralized with soda ash or dilute sodium hydroxide. The acid-modified starch is then filtered and dried. If the starch is washed with a nonaqueous solvent (89), gelling time is reduced, but such drying is seldom used. Acid treatment may be used in conjunction with preparation of starch ethers (90), cationic starches, or cross-linked starches. Acid treatment of 34 different rice starches has been reported (91), as well as acidic hydrolysis of wheat and com starches followed by hydroxypropylation for the purpose of preparing thin-hoiling and nongelling adhesives (92). 

Research on nasal powder drug delivery has employed polymers such as starch, dextrans, polyacrylic acid derivatives (e.g., carbopol, polycarbophil), cellulose derivatives (microcrystalline cellulose, semicrystalline cellulose, hydroxypropylmethyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose), chitosan, sodium alginate, hyaluronans, and polyanhydrides such as poly(methyl vinyl ether-co-maleic anhydride) (PVM/MA). Many of these polymers have already been used as excipients in pharmaceutical formulations and are often referred to as first-generation bioadhesives [38-45], In nasal dry powder a single bioadhesive polymer or a... 

Tapioca Starch ether Hydroxypropylated and thinned starch Gums... 

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-chloro-2-hydroxypropyl 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-dimethylarninoethyl 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-chloro-2-hydroxypropyl or 2,3-epoxypropyl 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 diethylaminoethyl starch (109) as well as the production of cationic starches from the reaction of alkaline starch with... 

Starches have been chemically modified to improve their solution and gelling characteristics for food applications. Common modifications involve the cross linking of the starch chains, formation of esters and ethers, and partial depolymerization. Chemical modifications that have been approved in the United States for food use, involve esterification with acetic anhydride, succinic anhydride, mixed acid anhydrides of acetic and adipic acids, and 1-octenylsuccinic anhydride to give low degrees of substitution (d.s.), such as 0.09 [31]. Phosphate starch esters have been prepared by reaction with phosphorus oxychloride, sodium trimetaphosphate, and sodium tripolyphosphate the maximum phosphate d.s. permitted in the US is 0.002. Starch ethers, approved for food use, have been prepared by reaction with propylene oxide to give hydroxypropyl derivatives [31]. 

Hydroxypropyl starch is produced industrially from natural starch, using propylene oxide as the modifying reagent in the presence of alkali, adding hydroxypropyl (CH(OH)CH2CH3) groups at the OH positions by an ether linkage. 

Additional information on starch ethers has been reported by Pringsheim,1264 Hjermstad1265 as well as Banks and coworkers,1266 and Mishler1267 [only (hydrox-yethyl)starch], Omae and coworkers1268 [only (hydroxypropyl)starch adhesives], Hjermstad,1269 Mehltretter,1270 Moser1271 [(hydroxyethyl)starch], Tuschhoff1272 [(hydroxypropyl)starch], and Wurzburg1273 (crosslinked starches). 

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