Determination of Size Distribution of Macropores in Porous Materials Macroporosity of Coke by Gas Flow Method S \ H f t I EI- a modified Kappelmeier method. DETERMINATION OF NITROGEN IN NITROCELLULOSE
The nitrate nitrogen content of nitrocellulose can be determined accurately by measuring the nitric oxide evolved from i t by means of the well-known D u Pont nitrometer ( I ) , or a D u Pont type of semimicronitrometer ( 6 ) , or by the Devarda ( 4 )
or lluraour (IS') methods in which the iiitrata nitrogeri is reduced t o ammonia and distilled. The Du Pont nitrometer method, though accurate, requires the use of a large amount of mercury and careful training of analysts; the Devarda and Mumour methods are too lengthy for control work. The Dumas combustion method cannot be applied easily to a flammable material such as nitrocellulose, and the Schultz-Tiemann ( 5 ) method is apparently not sufficiently accuratr. The more recent titration method of Leclercq and Math6 (fa) i* suitable onl>- for those types of nitrocellulose which dissolve readily in 9501, sulfuric acid a t 0" C. Of the foregoing methods. only that of Devarda is applicable to films and mixtures of nitrocellulose with resins and plasticizers, and even this method often yields unsatisfactory results when applied to such mictures. From time to time the feasibility of a rapid titration mrthod applicable to all types of nitrocellulose hae been considered. One
