Water-soluble cellulose sulphate - by alkali-activation and acid-regeneration of cellulose, dehydration with propanol, sulphating with sulphuric acid-propanol, etc.

摘要

A process for the prodn. of water-soluble cellulose sulphate in the alkali salt form (I) by heterogeneous sulphation of high-moL.wt. cellulose raw material (II) using H2SO4/ propanol (III)/(IV) as reaction medium/sulphating agent after prior activation with (partly) aq. alkali, regeneration of the cellulose with acid, washing out the salts formed and converting the sulphate half-ester into an alkali salt; the novelty is that the cellulose material obtd. after activation and washing out is dehydrated by treatment with (IV) without intermediate isolation, the wt. ratio of cellulose:(IV) in the fibre pulp is adjusted to (1:2)-(1:10), the pulp is cooled to sulphating temp. and a separately prepd. (III)/(IV) mixt. is added so that the mol. ratio (III):n-propanol in the reaction mixt. is 1.1-2.5 and the mol. ratio (III):iso-propanol is 1.3-2.5, and sulphation is carried out for 5-120 mins. at (-) 10 - (+) 15 deg.C. USE/ADVANTAGE - (I) is useful as an auxiliary substance for biotechnological and medicinal applications. The process provides a heterogeneous process for the prodn. of (II) . which is completely water-soluble, een at low mean degree of substitn., using less (III) and smaller amts. of hazardous/toxic chemicals than prior-art processes.