Inorganic oxidizers

The standard redox potentials of inorganic oxidants used in organic synthesis are generally around or above + 1.0 V. Organic substrates do not have such high potentials. The values for the CH4/CH3OH and CjHj/CjHjOH couples are at +0,59 V and 0.52 V, respectively. The oxidation of alcohols and aldehydes corresponds to values around 0.0 V (W.M. 

Type IV isotherms are often found with inorganic oxide xerogels and other porous solids. With certain qualifications, which will be discussed in this chapter, it is possible to analyse Type IV isotherms (notably those of nitrogen at 77 K) so as to obtain a reasonable estimate of the specific surface and an approximate assessment of the pore size distribution. 

Oxidizers. The characteristics of the oxidizer affect the baUistic and mechanical properties of a composite propellant as well as the processibihty. Oxidizers are selected to provide the best combination of available oxygen, high density, low heat of formation, and maximum gas volume in reaction with binders. Increases in oxidizer content increase the density, the adiabatic flame temperature, and the specific impulse of a propellant up to a maximum. The most commonly used inorganic oxidizer in both composite and nitroceUulose-based rocket propellant is ammonium perchlorate. The primary combustion products of an ammonium perchlorate propellant and a polymeric binder containing C, H, and O are CO2, H2, O2, and HCl. Ammonium nitrate has been used in slow burning propellants, and where a smokeless exhaust is requited. Nitramines such as RDX and HMX have also been used where maximum energy is essential. 

Characteristics of common inorganic oxidizers are Hsted in Table 5. In any homologous series, potassium perchlorate-containing propellants bum fastest ammonium nitrate propellants bum slowest (79,80). 

Fire Resista.nce. Many fillers, particularly inorganic oxides, are noncombustible and provide a measure of passive fire resistance to filled plastics by reducing the volume of combustible matter in the filled composition. Depending on their density, they may also serve as insulation. 

Sulfur tetrafluoride reacts with most inorganic oxides and sulfides to give the corresponding fluorides (103) ... 

The ozonides are characterized by the presence of the ozonide ion, O - They are generally produced by the reaction of the inorganic oxide and ozone (qv). Two reviews of ozonide chemistry are available (1,117). Sodium ozonide [12058-54-7] NaO potassium ozonide [12030-89-6] 35 rubidium ozonide [12060-04-7] RbO and cesium ozonide [12053-67-7] CsO, have all been reported (1). Ammonium ozonide [12161 -20-5] NH O, and tetramethylammonium ozonide [78657-29-1/, (CH ) NO, have been prepared at low temperatures (118). 

Because thiols are easily oxidized, a host of organic and inorganic oxidants may be used. Mild oxidants such as oximes, nitro compounds, or air can be effective. Various oxidants have been used in special appHcations, but only a few are used in large-scale appHcations. 

Pillared clays are smectite minerals or iUite-smectite minerals that have been stmcturaHy modified to contain pillars of stable inorganic oxide. The pillars prop open the smectite stmcture so they have a basal space of approximately 3.0 nm. Typical metals in the pillars include Al, Zr, Ti, Ce, and Fe, and these materials are used in catalytic processes to crack heavy cmde oils (110—112). 

A significant recent advance has been the development of MF and UF membranes composed of inorganic oxides.1113 These are currently produced by two main techniques ... 

An important class of expl materials contains metallic fuels and inorganic oxidants. Examples are Tritonal (TNT/A1, 80/20), Amatols (TNT/AN, 28/80 80/20), and Minol-2 (TNT/AN/A1, 40/40/20). Oxidants other than nitrates, such as chlorates and perchlorates, may be employed. Water solns containing these cations are highly corrosive to metals. Alkaline metal salts, for example, in the presence of moisture, will pit A1 quickly (Ref 6)... 

Inorganic oxides are usually prepd by intimate contact between the element and oxygen or air. The reaction may be rapid and exothermic, as when finely divided pyrophoric materials ignite spontaneously in air or oxygen. Examples of these materials are iron, lead and phosphorus.-Or, the reaction may be slow as when iron oxidizes when exposed to ordinary moist air, or when aluminum oxidizes at the surface upon exposure to air. Much of the time oxidation re-... 

Other methods of prepn include the heating of nitrates, as for Na20 of carbonates, as for CaO or of hydroxides, as for MgO. Of course, many inorganic oxides occur in nature as ores. Examples of these are Fe203, Fe304 and Sn02 For individual methods of prepn, see under the selected inorgenic oxides described below... 

Several toxic effects of inorganic oxides become evident when oxides are inhaled in a finely powdered form. A high concn of powdered oxides can lead to asphyxiation on short exposure or lung cancer at somewhat lower concns if the exposure occurs over a prolonged period. 

Blood poisoning can occur if an inorganic oxide such as As2 03 is allowed to penetrate an open wound. Of course, oxides such as Na20 and CaO have a markedly corrosive action on all body tissue (Ref 38). The specific toxicities of selected inorganic oxides are presented below... 

The ordnance applications of inorganic oxides as ceramics are of considerable interest. One... 

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