Reaction of Aryl Isocyanates with Cotton Cellulose

Abstract

The thermal dissociations of cellulose N-(2-, 3-, and 4-pyridyl)-carbamates to their respective isocyanates and cellulose were investigated using dynamic and isothermal thermogravimetric analyses. With the aid of a digital computer, kinetic parameters were determined for the dissociation reactions measured by both techniques. First-order kinetics were ob served in every case. Activation energies ranged from 28 to 45 kcal/mole. Entropy of activation values were positive for the 4-isomer and negative for the 2- and 3-isomers. The intermediate postulated for the more thermally labile 4-isomer results from intermolecular catalysis, while those for the 2- and 3-isomers resulted from intramolecular catalvsis.