Reaction of tetrachlorophthalic anhydride with cellulose derivatives

Tetrachlorophthalic anhydride (TCPA) was reacted with cellulose diacetate and with cellulose diethyl ether in dioxane solution to produce esters with rather low tetrachlorophthalyl contents. Phthalic anhydride was found to be considerably more reactive than was TCPA with these cellulose derivatives, especially if pyridine was used as the reaction solvent. Acylations could not be executed with TCPA in the presence of pyridine as solvent, however, because this material decomposed the anhydride, removing chlorine from it. The TCPA derivatives were more limited in solubility than were the corresponding esters made from phthalic anhydride.