(United States Patent and Trademark Office, 1996-06-04)
The invention is directed to the formation of cellulose derivatives using homogenous phase reaction conditions. Cellulose is dissolved using DMAc/LiCl and a reagent system is added to promote the acylation of an appropriate acid anhydride or free carboxylic acid. One reagent system includes N,N-dicyclohexylcarbodiimide (DCC) and 4-pyrrolidinopyridine (PP). Another reagent system includes p-toluene sulfonyl chloride (TsCl) and pyridine (Py).
(United States Patent and Trademark Office, 2017-07-18)
The present invention relates to esters of diacids and cellulosic materials and methods for making thereof. The ester has the chemical composition of Formula (1) Formula I where R1, R2, and R3 can be the sameordifferent, and each of which is selected from —-H, —COR', —R"™, or —COR" COORH,with the proviso that at least one of the R1, R2, or R3 is —COR" COOH; R'is an alkyl, alkenyl, alkynyl, or aromatic group; R" is an alkyl, alkenyl, or alkynyl group having 4 or more carbon atoms (=C,); and R™ is an alkyl, alkenyl, alkynyl, polyol, or aromatic group.