Patent ID: 7402668

Claim:
A process for preparing alkylhydroxyalkylcellulose comprising the steps of: (a) alkalizing cellulose with 0.9 to 2.9 equivalents of alkali metal hydroxide/AGU in a suspension medium containing alkyl halide, wherein said alkyl halide is present in an amount from that at least equivalent to the equivalents of alkali metal hydroxide present to an amount at most equivalent to the equivalents of alkali metal hydroxide present plus 4.5 equivalents, and wherein said alkali metal hydroxide is in the form of an aqueous alkali metal hydroxide solution; (b) adding hydroxyalkylating agent to the alkalized cellulose of step (a) at a temperature above 65° C. to form a reaction mixture; (c) adding alkali metal hydroxide to the reaction mixture of step (b), wherein said alkali metal hydroxide is in the form of an aqueous alkali metal hydroxide solution; (d) isolating alkylhydroxyalkylcellulose from the reaction mixture of step (c) and optionally purifying said alkylhydroxyalkylcellulose.