GB458596A - Improvements in the manufacture of cellulose derivatives and products obtained therefrom - Google Patents

Abstract

Cellulose ether-esters are prepared by subjecting to esterification a partial ether of cellulose, other than an ether containing oxyalkyl groups, produced under substantially anhydrous conditions in the presence of an organic base. Suitable cellulose ethers are those obtained by the process described in Specification 458,597. The ethers preferably contain only a small proportion of ether groups, for example, \ba1/4\be to \ba1/2\be up to about 1 ether group per cellulose molecule. The esterification may be carried out by means of an acid anhydride, such as acetic, propionic, or benzoic anhydride, in the presence of sulphuric acid as a catalyst. The primary cellulose ether-esters may be employed directly for the manufacture of artificial filaments, films, and the like, or may first be ripened. In examples: (1) an ethyl cellulose produced under anhydrous conditions in the presence of an organic base and containing 0,8 ethyl groups per molecule, p is esterified by means of acetic anhydride in the presence of acetic acid and sulphuric acid, and (2) an ethyl cellulose containing one ether group per molecule, prepared by the process described in Specification 458,597, is esterified by means of acetic anhydride in the presence of acetic acid, ferric chloride and hydrochloric acid. Specifications 207,562, 308,322, 308,323, 309,201, 312,095, 312,096, 312,098, [all in Class 2 (ii)], 314,446, 314,447, [both in Class 15 (ii)], 316,521, 318,468, [both in Class 2 (ii)], 323,790, [Class 2 (iii)], 340,324, 340,325, 340,436, 340,437, 351,417, 370,430, 380,504, 380,505, 389,823, 402,104, 402,106, 428,224, 429,103, 430,349, 430,350, 430,351, 430,352, 430,489, 432,027, 432,028, 438,584, 438,585, 438,586, 438,587, 438,655, 438,656, 443,707, and 443,773 also are referred to.