Studies on Chitin. V. Formylation, Propionylation, and Butyrylation of Chitin

Variously substituted propionylchitin, and butyrylchitin were prepared using the corresponding carboxylic acid, carboxylic anhydride or their mixture in methanesulfonic acid at low temperatures. Formylchitin derivatives with different degrees of formylation were prepared from a formic acid–methanesulfonic acid mixture. Highly substituted butyrylchitin is easily soluble in common organic solvents such as dioxane, tetrahydrofuran, acetone, acetonitrile, dimethyl-formamide, acetic acid, and methanol in addition to acidic solvents such as formic acid and dichloroacetic acid. Other acylchitins are soluble only in acidic solvents. The viscometric behavior of a chitin solution in methanesulfonic acid and the infrared absorption spectra of the acylchitin derivatives were also investigated.