GB611665A - Improvements in the production of cellulose esters - Google Patents

Abstract

A partially hydrolysed cellulose ester of a lower aliphatic acid is subjected to the washing or leaching action of hot distilled water to render it more reactive, and is then converted into a mixed ester of cellulose by reacting it with a long chain aliphatic acid esterifying agent such as the acid chloride. The long chain esterifying agent may contain 12-20 carbon atoms. The cellulose ester may be treated with 24-60 volumes of distilled water at 80-100 DEG C. A single treatment or several treatments with distilled water may be given. Following the activation treatment, the hydrolysed lower aliphatic ester of cellulose is dried and it is then ready for the further esterification. It may be dissolved in pyridine at a temperature of 50 DEG to 70 DEG C. and may then be heated with the acid chloride of a long chain aliphatic acid at 85 DEG to 100 DEG C. The product may be isolated by diluting the pyridine solution with acetone, methyl acetate, or dioxane, and then streaming the solution into water, whereby the cellulose ester is precipitated. The production of cellulose acetatelaurates is described. These may contain 0.6 to 0.8 free hydroxyl groups, 0.5 to 0.8 lauryl groups, and 1.4 to 1.75 acetyl groups per glucose residue. The products may be moulded at 165 DEG to 200 DEG C. The freshly precipitated cellulose acetate-laurate may be washed with hydrochloric acid, dried, ground, extracted with ether, and then stabilized by heating under pressure with very dilute sulphuric acid. It may then be washed with aqueous alcohol and then with water.