GB415383A - Improvements in the manufacture of carbohydrate compounds - Google Patents

Abstract

In the manufacture of oxyalkyl ethers of carbohydrates suitable for use as sizes, dressings and finishes for textile and other purposes, the carbohydrates are reacted with alkylene oxides under pressures of at least five atmospheres. The invention is concerned more particularly with the production of cellulose ethers containing 1--2 oxyalkyl groups per C6H10O5. The temperature may be such that the alkylene oxide is wholly liquid or it may be partially or wholly gaseous and the pressure may be due entirely to the vapour of alkylene oxide or may be partly due to the presence of other gases or vapours, e.g. nitrogen or carbon-dioxide. The reaction may be carried out in the presence of acids or acid salts, alkalies, or bases. Cellulose may be pretreated with acids or bases, strong acids when used for such a treatment being preferably removed before the oxyalkylation. The reagents used for the oxyalkylation include ethylene oxide and its homologues, glycide, epichlorhydrin or mixtures of alkylene oxides. When using the epichlorhydrin type of reagent, if the halogen atom constitutes the etherifying group alkali must be present, while if the alkylene oxide group is to react, the reaction should be under neutral or acid conditions. The oxyalkyl derivatives may be esterified, to produce substances suitable for the production of lacquers, plastics, filaments or films by the usual methods, the said products being then subjected, if desired, to any suitable after treatment processes. In an example, cotton linters containing about 10 per cent by weight of caustic soda are heated with 2--4 times their weight of ethylene oxide at a temperature of 80--100 DEG C. and a pressure of 6--8 atmospheres for 4--6 hours, or until the desired content of ether groups is obtained. In a modification, cotton linters pretreated with acetic acid are treated with 2--4 times their weight of ethylene oxide in the presence of nitrogen or other inert gas at a temperature of 40--60 DEG C. and a pressure of 12--15 atmospheres, and in a third example, cotton linters either pretreated with acetic acid or containing about 10 per cent of caustic soda are heated with 3--5 times their weight of propylene oxide in the presence of nitrogen at a temperature of 50--70 DEG C. and a pressure of 25--30 atmospheres. British Specifications 165,519, 177,868, 179,234, 198,023, 203,092, 249,173, 263,938, 277,089, 300,998, 323,790, 325,233, [all in Class 2 (ii)], 340,324, 340,325, 340,436, 340,437, 343,062, 370,430, 371,461, 380,504, 380,505, 389,823, 392,185, 397,116, 397,117, 400,589, 400,597, 403,106, 405,619, 405,676, 405,692, 406,337, 406,985, 407,018, 407,351, 407,673, 412,601; 414,751, [Group VIII], 415,382, and French Specification 565,654 are referred to.