AbstractNitratability of three different polymeric dextrans with predominantly α‐1,6‐linked anhydro‐D‐glucopyranose units was studied in different nitrating agents. The degree of substitution (D. S.) increases with increase of the absolute nitric acid/dextran ratio. Due to gelatinization of dextrans in this medium, this nitrating agent is comparatively less effective for dextran nitration than for starch with predominantly α‐1,4‐D‐glycosidic linkages; the latter has great affinity to dissolution in this medium. Nearly complete nitrations (D. S., 2.96) were readily obtained from dextrans by nitration in presence of 25% each of acetic acid and acetic anhydride.In nitric‐sulphuric acids mixtures the nitratability of dextran is mainly a function of acids composition. Gelatinization occurred in mixed acids containing up to 20% H2SO4. Successful nitrations (D. S., ca. 2.6) were always obtained, however, from mixed acids containing 38% or more sulphuric acid, but the use of 62% sulphuric acid is more economic for industry. The sulphate content is greatly dependent on the acids composition and it is, as well, affected by the chemical nature of the corr