Aluminum nitrate decomposition

Aluminum nitrate is available commercially as aluminum nitrate nonahydrate [7784-27-2], A1(N02)3 9H20. It is a white, crystalline material with a melting point of 73.5°C that is soluble in cold water, alcohols, and acetone. Decomposition to nitric acid [7699-37-2], HNO, and basic aluminum nitrates [13473-90-0], A1(0H) (N03) where x + = 3, begins at 130°C, and dissociation to aluminum oxide and oxides of nitrogen occurs above 500°C. 

Alumina having strong catalytic action may be prepared by precipitating the aluminum from a one to two per cent aluminum nitrate solution with dilute ammonia. The precipitate is washed by decantation six times, washed on the filter several times, dried over phosphorous pentoxide for 24 hours, heated in an air oven at 240° C., and ground to pass a 200 mesh sieve. After operating for five hours at a temperature close to 500° C. this catalyst showed but a slight decrease in activity.84 An 80 per cent yield of 98 per cent ethylene was obtained from absolute alcohol at 490° C. When water and alcohol were passed in together somewhat more aldehyde decomposition was obtained. 

Write a balanced equation for the thermal decomposition of aluminum nitrate to form aluminum oxide, nitrogen dioxide, and oxygen gas. 

Anhydrous aluminum nitrate [13473-90-0] is covalent in character, easily volatilized, and decomposes on heating (22). Hydrated aluminum nitrate is used in the preparation of insulating papers, on transformer cote laminates, and in cathode-ray tube heating elements. Solution of aluminum hydroxide through digestion of cote materials in nitric acid has been proposed in aluminum extractive metaUuigy. The resulting solution of aluminum nitrate is separated from other metal ions, and the aluminum oxide is recovered by thermal decomposition of the aluminum nitrate solution (23,24). 

Aluminas can also be prepared by thermal decomposition of aluminum salts. Aluminum nitrate decahydrate decomposes at a temperature of 180 °C producing amorphous alumina (100) the spray pyrolysis of aluminum nitrate solutions yields y-Al203 (80). 

Figure 5. Change in relative intensities of nitrogen, oxygen, and aluminum ion peaks during thermal decomposition of aluminum nitrate.

These normally utilize the low- and medium-temperature decomposition of inorganic aluminum salts and hydroxides, or metal-organic compounds of aluminum. Typical precursors include aluminum nitrate and aluminum hydroxides. Hydro-thermal conditions are often applied [8], but colloidal methods (sol-gel) have been extensively studied over the past three decades [9-11]. Recent efforts have been aimed at reducing the particle size of a-Al203, and decreasing the temperature of formation of a-Al203 from transient aluminas to <1000 °C [12]. Results similar to those in sol-gel can be achieved with the use of metal ion-polymer-based precursor solutions. Here, the precursor solution (e.g., nitrate salt) is mixed with a water-soluble polymer, which provides a matrix for the dispersion of cations [13]. 

The excess addition of ammonium nitrate produces an increase in combustion gas, and the effect of expanding the microstructure and eventually increasing the surface area of the produced powder. As can be seen, the decomposition of ammonium nitrate generates, in part, the same gases obtained for the pair of aluminum nitrate and glycine, according to Eq. 2.1. 

Synonyms Aluminum Nitrate Nonahydrate Nitric Acid, Aluminum Salt Chemical Formula Al(N0j)j 9H20 Hi) Observable Characteristics — Physical State (as normally shipped) Solid Color White Odor None (iii) Physical and Chemical Properties — Physical State at 15 °C and I atm. Solid Molecular Weight 375.13 Boiling Point at I atm. Not pertinent (decomposes) Freezing Point 163, 73, 346 Critical Temperature Not pertinent Critical Pressure Not pertinent Specific Gravity > 1 at 20°C (solid) Vapor (Gas) Density Not pertinent Ratio of Specific Heats of Vapor (Gas) Not pertinent Latent Heat of Vaporization Not pertinent Heat of Combustion Not pertinent Heat of Decomposition Not pertinent (iv) Health Hazards Information — Recom-... 

In the solvent extraction step thorium and uranium are co-extracted in the first cycle subsequent partitioning of thorium and uranium in the second cycle gives two decontaminating cycles to both products while using only five columns. For short-decayed thorium a reductant, sodium hydrogen sulfite, is continuously added to the feed streams of both cycles to decrease the effect of nitrite formed by irradiation. Without the sulfite addition, the nitrite formed by radiation decomposition of nitrates converts ruthenium to a solvent-extractable form. Acid deficiency in the second cycle feed is achieved by adding dibasic aluminum nitrate (diban). 

A novel, mild system for the direct nitration of calixarenes has been developed using potassium nitrate and aluminum chloride at low temperature. The side products of decomposition formed under conventional conditions are not observed in this system, and the p-nitro-calixarenes are isolated in 75-89% yields.17 Such Friedel-Crafts-type nitration using nitryl chloride and aluminum chloride affords a convenient system for aromatic nitration.18 Nitryl chloride was previously prepared either by the oxidation of nitrosyl chloride or by the reaction of chlorosulfonic acid with nitric acid. However, these procedures are inconvenient and dangerous. Recently, a mixture of sodium nitrate and trimethysilyl chloride (TMSC1) has been developed as a convenient method for the in situ generation of nitryl chloride (Eq. 2.6). 

The precise reactions involving the decomposition of ammonium ions and nitrate ions at the anodic surface to form N-doped titania are currently unclear, and the subject of ongoing studies. However, the anodization of aluminum in nitric acid has been studied previously and is known to be relatively complex... 

Because of its higher melting point and less-exothermic decomposition, potassium perchlorate produces mixtures that are less sensitive to heat, friction, and impact than those made withKClO] [2]. Potassium perchlorate can be used to produce colored flames (such as red when combined with strontium nitrate), noise (with aluminum, in "flash and sound" mixtures), and light (in photoflash mixtures with magnesium). 

Therefore, the initial choice for an oxidizer is one with an exothermic heat of decomposition such as potassium chlorate (KCIO 3). However, mixtures of both chlorate and perchlorate salts with active metal fuels are too ignition-sensitive for commercial use, and the less-reactive - but safer - nitrate compormds are usually selected. Potassium perchlorate is used with aluminum and magnesium in some "photoflash" mixtures these are extremely reactive compositions, with velocities in the explosive range. 

Z-Eburnamonine (XXXVI) has been produced by other reactions of vincamine. Oxidation of vincaminic acid (XL R = H) by means of ammoniacal silver nitrate was one way, and periodic acid fission of vincaminol was another (16). A different group of workers, who had probably attempted to prepare vincaminol by lithium aluminum hydride reduction of vincamine, obtained instead Z-ebumamonine in excellent yield (18). This has been rationalized as illustrated (partial formulas) by analogy with the base-induced decomposition of formic esters to carbon monoxide and alkoxide ion ... 

Thermal decomposition of Al(N03)2N20s produces anhydrous A1(N03)3. All the nitrates of aluminum are powerful oxidants and may react explosively with organic solvents. They also decompose to oxides rather readily, as low as 65 °C in the case of A1(N03)3. 

ACGIH TLV TWA 2 mg(Al)/m3 DOT CLASSIFICATION 5.1 Label Oxidizer SAFETY PROFILE A poison. A severe eye and mild skin irritant. A powerful oxidizer. When heated to decomposition it emits toxic NOx. See NITRATES and ALUMINUM COMPOUNDS. A nitrating agent. 

SAFETY PROFILE A poison by ingestion, subcutaneous, parenteral, and intravenous routes. An irritant to skin and eyes. When heated to decomposition it emits vety toxic fumes of NO. An oxidizer. Mixtures with finely divided aluminum-magnesium alloys are easily ignitable and extremely sensitive to friction or impact. Such mixtures are used in chemical photoflash applications. Incompatible with (Mg + Ba02 + Zn), Al, and Mg alloys. When heated to decomposition it emits toxic fumes of NOx. See also BARIUM COMPOUNDS (soluble) and NITRATES. 

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