Process for the derivatization of cellulose

摘要

There is disclosed a process for the derivatization of cellulose comprising the sequential steps: a) mixing cellulose with a viscosity below 900 ml/g with an aqueous solution to obtain a liquid, wherein particles comprising cellulose in said liquid have a diameter of maximum 200 nm, wherein the temperature of the aqueous solution is below 20° C., and wherein the pH of the aqueous solution is above 12, b) subjecting the liquid to at least one of the steps: i) decreasing the pH of the liquid with at least 1 pH unit, ii) increasing the temperature by at least 20° C., and c) derivatization of the cellulose. Advantages include that there is provided the possibility to derivatize cellulose faster and to a greater extent after the treatment. Further the yield is improved. The product quality is improved and the manufacture is cheaper and easier.

主权项

1. A process for derivatization of cellulose comprising:
a) mixing cellulose with a viscosity below 900 ml/g with an aqueous solution to obtain a liquid, wherein said liquid is selected from the group consisting of a solution of cellulose, and a combination of a solution of cellulose and a colloid system comprising cellulose comprising cellulose particles having a diameter of 200 nm or less, wherein cellulose which has not been dissolved and/or suspended to a particle size with an average diameter of between 5-200 nm is removed, wherein particles of cellulose in the liquid have an average diameter of between 5-200 nm and wherein the aqueous solution has a temperature below 20° C., and a pH above 12; b) subjecting the liquid to at least one step selected from the group consisting of
i) decreasing the pH of the liquid by at least 1 pH unit, andii) increasing the temperature of the liquid by at least 20° C.; and c) derivatization of the cellulose in the liquid.