PROCESS FOR THE PREPARATION OF SUBSTITUTED GRANULAR STARC

摘要

1533228 Granular starch ethers and esters NATIONAL STARCH & CHEMICAL CORP 13 June 1977 [12 July 1976] 24588/77 Heading C3U Substituted granular starch products are prepared by (a) reacting a granular starch base in an aqueous system with 0À5-15% by dry weight of starch of a reagent capable of reacting with free hydroxyl groups in the starch base to produce acetal cross-linkages; (b) reacting the crosslinked starch under alkaline conditions with a mono-functional esterifying or etherifying reagent and (c) removing the acetal crosslinkages in the esterified or etherified product by treatment with acid. The crosslinking agent may be an aliphatic 2-5 C monoaldehyde or a 3-5 C aliphatic dialdehyde and the preferred etherifying and esterifying agents are ethylene oxide, propylene oxide, butylene oxide, 1,2-epoxybutene, styrene oxide, allyl chloride, allyl bromide, benzyl chloride, benzyl bromide, sodium monochloroacetate, sodium monochloropropionate or dialkylaminoethyl chloride. The crosslinked product of step (a) may be reacted with an activated unsaturated organic compound, e.g. acrylonitrile, acrylamide or an acrylate ester.