It appears impossible to nitrate cellulose in a medium of liquid sulfur dioxide either ~~th ruming nitric acid, a mixture of fuming nitric acid and sulfuric acid t a mixture of fuming nitric acid and phosphorus pentoxide, a mixture of fuming nitric acid, phosphorus pentox1de ana chlorine gas, or with nitrogen tetroxide. This is attributed to the fact that in each case the primary reaction ist hat of the formation of the compound N23209.