Starch, gum, and cellulose derivatives containing aldehyde groups; their preparation from the corresponding acetals and use as paper additives

Abstract From the Canadian patent

Polysaccharide aldehydes having the general structure Y-, such as starch, cellulose and, gum aldehydes are useful for imparting wet, dry, or temporary wet strength to paper. They are prepared by a non-oxidative method which involves reacting the polysaccharide base in the presence of alkali, with a derivatizing acetal reagent having the general structure and then hydrolyzing the acetal by adjusting the pH to less than 7, preferably 2-4. R is (CH2)n or a divalent aromatic group and n is 0 or greater; R1, R6, and R7 are hydrogen or an organic group; R2, R5, and R8 are (CH2)m with m being 1-6; R3 and R4 are hydrogen or a lower alkyl; Y is an anion; Z is an organic group capable of reacting …