Nitric acid continued stabilizers

The SH-process involves continuous nitration of hexamethylenetetramine by concentrated nitric acid, with the production of nitrous gas. The RDX is filtered from the residual acid and stabilized by boiling in water under pressure and purified by recrystallization from acetone. 

S-H process (inventor Schnurr) continuous nitration of hexamethylenetetramine using highly concentrated nitric acid, accompanied by a decomposition reaction under liberation of nitrous gases, without destruction of the Cyclonite formed. The reaction mixture is then filtered to separate the product from the waste acid, followed by stabilization of the product by boiling under pressure and, if required, recrystallization. 

The spontaneous decomposition of nitrocellulose in the air pro duces nitrous and nitric acids which promote a further decomposition. If these products however arc removed continuously, the uncatalyzed decomposition is extremely slow, and smokeless powder may be stabilized by the addition to it of a substance which reacts with these acids and removes them, provided neither the substance itself nor the products of its reaction with the acids attacks the nitrocellulose. 

The solubility-temperature relationship for 1 hofheating of starch, with nitric acid as the catalyst, is presented in Fig. 11. The solubility of dextrins formed can be influenced by contact with the atmosphere. Vacuum, as well as air flow, favor the presence of soluble matter in dextrinized starch (see Fig. 12). However, the effect observed may be attributable to continuous removal of moisture. On the other hand, the results of the present authors showed that the course of dextrinization under nitrogen, carbon dioxide, and in air yields different dextrins of various solubility and stability after a given period of dextrinization. 

The precise mechanism resppnsible for the passivity conferred on metals by anodic inhibitors, such as chromate, is not known. While some early workers thought that a protective salt film (e.g., chromate) was formed, this view is not generally applicable, since passivity can occur in a system where the salt film would be freely soluble (e.g., iron in nitric acid). It is, however, generally accepted that passivity is associated with the formation of a protective film, and current views ascribe the action of anodic inhibitors either to adsorption at anodic sites or to continuous repair of the protective film. The former view has received attention in recent publications by Cartledge ), while the latter is favored by Evans (2). However, work on aluminum has suggested that true passivity is associated with the crystal structure of the film, which in turn determines its stability. This principle has recently been introduced by one of the authors (3) and is developed below into a general theory of passivity. 

Heavy rains leach out a portion of the bases in the mull layer and below, most of which are intercepted by the tree roots and returned to the surface again later with the annual leaf fall. Since the leachates are usually nearly neutral in reaction, they extract less mineral matter than where the percolating water is high in organic and nitric acids. This continuous cycling of nutrients accounts for stabilization of the soil with little tendency toward the distinct stratification and impoverishment that is characteristic of true podzols. 

Titanium tetraisopropoxide stabilized by acetjdacetone was dissolved in isopropyl alcohol. In addition, cobalt nitrate dissolved in ethanol was mixed. These two solutions were stirred continuously using a magnetic stirrer at room temperature. Dilute nitric acid (1 1) was added slowly to this solution and the temperature rises to 90 °C to form a gel. After 45 min, sudden self-combustion occurred with the evolution of large amounts of gases and flufiy foam-Uke mass. This product was dried in a hot air oven for 24 h at 110°C. The dried powder was milled and thermally treated at 800 °C for 3h to acquire crystallized nano- (submicron) powder. The CCTO pellets were sintered at a low temperature of 950 °C. A high value of dielectric constant, on the order of 10 , was measured due to the low sintering temperature and uniform microstructure. These results indicate that the CCTO is a future material in the electronic industry for various applications. 

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