This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1906 Excerpt: ...described. We subjoin the results of analyses of typical preparations of aceto-sulphates of the three series described in this paper. These preparations, which contained only traces of nonesterified cellulose, were not subjected intentionally to any process of fractionation with a view to separating different ...
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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1906 Excerpt: ...described. We subjoin the results of analyses of typical preparations of aceto-sulphates of the three series described in this paper. These preparations, which contained only traces of nonesterified cellulose, were not subjected intentionally to any process of fractionation with a view to separating different components. Their solubilities indicated that they were homogeneous substances, but the possibility of a certain amount of fractional dissolution or dissociation during the process of washing is not excluded. 1 A. G. Green in Ztschr. Farb. Textil. Ind., 3, 99, 309. See also ibid. 199 and p. 131. Methods.--The hygroscopic moisture was determined by drying in the water-oven for 2 hours at 980 C. Since the zinc salts were charred by this treatment, their dry substance was calculated on the same basis as the magnesium salts. The total H2SO4 was determined after destruction of the cellulose by aqua regia, by precipitation as barium sulphate. The acetic acid was determined by neutralising the products with caustic soda in presence of phenol-phthalein, and then saponifying by a known excess of caustic soda in presence of 60 p.ct. alcohol. Saponification was allowed to proceed for 40 hours in the cold, and the alkali thus neutralised was calculated in terms of acetic acid, on the assumption that, after the neutralisation of any dissociated free sulphuric acid, the residual combined sulphuric acid is very nearly resistant to the saponifying action of alcoholic soda. Nevertheless, the values for acetic acid by saponification cannot pretend to any high degree of accuracy; they indicate however, in an approximate manner, the degree of esterification attained in these compounds. (2) Intermediate Series. The dry zinc salts contained varying quantities of dissociated...
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