Water-sol. cellulose sulphate with high soln. viscosity - by heterogeneous sulphation of high mol. wt. cellulose with mixt. of propanol and sulphuric acid at specific temp.

摘要

A process is claimed for the prodn. of cellulose sulphate with high soln. viscosity (I), by heterogeneous sulphation of high-mol. wt. cellulose starting material (II) in a mixt. of propanol and sulphuric acid, opt. in the presence of toluene as dispersant; the novelty is that sulphation is carried out for 90-150 mins at (-) wo-10 deg.C with mol. ratio propanol:H2SO4 = (1:1.75)-(1:2) and bath ratio (sulphating mixt.);:(II) = (1:20)-(1:35), after which the reaction prod. is converted into an alkali salt by known methods and the water-soluble fraction is isolated. Pref. N-propanol is used for the above mixt.; (I) is produced as the Na salt, and (II) is added to a sulphating mixt. which, after its prodn., has been aged for 0.5-24 hrs. at -5 to 30 deg.C. USE/ADVANTAGE - The method provides a process for the heterogeneous sulphation of (II) under technically acceptable conditions, without pre-activation (contrast prior-art methods using aggressive and/or toxic reagents and/or involving difficult work-up procedures), and with much less redn. of chain length. (I) is useful as an auxiliary substance for biotechnical and medicinal applications.