Patent GB-1022810-A (GB)
Title: Starch derivatives
IPC: C08B31/12
Filed: 1964-12-02
Abstract: A cationic starch ether is made by reacting starch, in the presence of an alkaline catalyst, with a quaternary halohydrin salt which has been obtained by reacting hypohalous acid with an allyl quaternary halide salt of a tertiary amine, the allyl salt being essentially free from allyl chloride and allyl alcohol, and the tertiary amine being either (1) an amine having, as the three substituents on the nitrogen atom, alkyl groups with up to 12 carbon atoms, or cyclohexyl, phenyl or benzyl groups, such that, when the three substituents are the same, none has more than 6 carbon atoms, and when any one substituent has more than 6 carbon atoms, the other two are methyl or ethyl; or (2) a heterocyclic tertiary amine in which the third substituent on the ring nitrogen is an alkyl group containing not more than 4 carbon atoms, and the heterocyclic ring is morpholinyl, pyrrolidyl or piperidyl, each having up to one alkyl ring substituent containing not more than 2 carbon atoms.  The formation of the starch ether may be represented as follows <FORM:1022810/C3/1> where X is halogen, N(R1R2R3) is the tertiary amine moiety and MOH is alkaline catalyst. Many tertiary amines and catalysts are specified. A preferred etherification reagent is chlorohydroxypropyl trimethylammonium chloride.  The reaction may be carried out at 10 DEG -200 DEG  C., suitably at least 30 DEG  C. below the gelatinization temperature of the starch.  In one embodiment, granular starch is etherified in a medium of lower alcohols, dioxane, or aqueous inorganic salt solutions to yield a granular cationic starch ether, or an aqueous or dimethyl sulphoxide paste of starch is etherified.  The etherifying reagent may be cyclised to form an epoxy compound before addition of the starch. In further embodiments, etherification is effected by tumbling and heating superficially dry starch granules with finely divided catalyst and etherification reagent, or by heating and extruding a mixture of starch, catalyst, reagent and plasticizer, e.g. water. The etherification may be carried out under nitrogen.  The starch starting material may be natural starches and dextrins, including amylopectin, waxy and high amylon starches, starches modified by treatment with acids (with introduction of carboxyl groups) enzymes, heat or oxidizing agents, or starches derivatized by reaction with, e.g. acetic anhydride, vinyl acetate or ethylene oxide.ALSO:A halohydrin quaternary salt is made by reacting hypohalous acid with an allyl quaternary halide salt of a tertiary amine, the allyl salt being essentially free from excess allyl halide and allyl alcohol and the tertiary amine being either (1) a tertiary amine having as the three nitrogen substituents, alkyl groups of up to 12 carbon atoms, cyclohexyl, phenyl or benzyl groups such that, when the three substituents are the same, none has more than 6 carbon atoms, and when any one substituent has more than 6 carbon atoms, the other two are methyl or ethyl or (2) a heterocyclic tertiary amine in which the third nitrogen substituent is an alkyl group having up to 4 carbon atoms and the heterocyclic ring is morpholinyl, pyrrolidyl or piperidyl, each having up to one alkyl ring substituent containing not more than 2 carbon atoms.  The reactions may be represented as follows:  <FORM:1022810/C2/1> The preparation of vic-chlorohydroxypropyl trimethyl ammonium chloride by passing Cl2 into an aqueous solution of allyltrimethyl-ammonium chloride (from allyl chloride and trimethylamine) is described.