Disclosed is a process for the deacetylation of chitin and a process for the treatment of chitinaceous materials to obtain chitin which processes are conducted in a non-saponifiable, non-aqueous, water insoluble liquid having a flash point greater than about 100.degree. C., preferably a non-aromatic hydrocarbon. The process for the deacetylation of chitin comprises suspending chitin in the hydrocarbon liquid, preferably from about 0.02 g/cc to about 0.2 g/cc, mixing therewith an alkali metal hydroxide solution, and heating the suspension at a temperature at least about 70.degree. C. for a period of time sufficient to obtain the desired degree of deacetylation. The concentration of alkali metal hydroxide in the alkali metal hydroxide solution is at least 30% by weight, preferably at least 40% by weight, and most preferably at least 50% by weight, and the quantity of alkali metal hydroxide is sufficient to provide an alkali metal hydroxide to chitin weight ratio from about (0.35)(AMHMW)/40 to about (2.5)(AMHMW)/, 40 where AMHMW is the molecular weight of the alkali metal hydroxide.