Ammonia gas atmosphere

Remove the organic polymer in an ammonia gas atmosphere and sinter the remaining in a furnace. Upon heating, the volatile components escape and the nickel oxide fiber surface becomes uniformly porous to form a nickel oxide membrane. Significant shrinkage can be expected. 

Figure 3.8 Monitoring the structural transformation with temperature and ammonia gas atmosphere starting from gallium nitrate reaching a spinel-type structured gallium...

A mixture of 5 parts of 3-(2 -ethyl-2 -nitrovinyl)indole in 80 parts of ethanol saturated with ammonia gas is shaken in an atmosphere of hydrogen at 100 atmospheres pressure and at 20°C... 

The most important step in the process for the conversion of atmospheric nitrogen into important commercial compounds such as fertilizers and explosives involves the combination of one volume of nitrogen gas with three volumes of hydrogen gas to form two volumes of ammonia gas. 

To be specific, consider the data for 17.0 grams of ammonia gas at 25°C, as presented in Table 4-1 (p. 51). These data show that PV = 24.5, but a complete statement should include both the uncertainty and the range over which the data are known to apply. In this case the uncertainty is 0.7 and the range is 0.2-2 atmospheres pressure. It would not be safe, from these data alone, to assume that the pressure-volume product is constant to four significant figures, PV = 24.50. Neither would it be safe to assume that the pressure-voiume product is constant outside the range of pressure studied, 0.2-2.0 atmospheres. Remember, a generalization is reliable within... 

A final category of encapsulating materials consists of reaction products of the nucleus material and a reagent. For example, pellets of nitronium perchlorate have been encapsulated in shells of the less reactive amm perchlorate (AP) by exposing the pellets to ammonia gas. The fragile AP shells were usually further protected by a top-coating of A1 or a polymer film (Ref 2). The most familiar example of this process is the natural one wherein A1 powders (or articles) become coated with a protective coating of A1 oxide thru exposure to atmospheric air... 

Ammonia gas is diffusing at a constant rate through a layer of stagnant air 1 mm thick. Conditions are such that the gas contains 50 per cent by volume ammonia at one boundary of the stagnant layer. The ammonia diffusing to the other boundary is quickly absorbed and the concentration is negligible at that plane. The temperature is 295 K and the pressure atmospheric, and under these conditions the diffusivity of ammonia in air is 1.8 x 10 5 m2/s. Estimate the rate of diffusion of ammonia through the layer. 

Note The TDM reagent can be used everywhere, where o-tolidine is employed. It can also be used on chromatograms, that have already been treated with ninhydrin, Pauly or ammonia perchlorate reagent or with iodine vapor [1]. Water may be used in place of 80% 2-propanol when making up solutions II, III and IV. The chlorine gas atmosphere in the chromatography chamber can also be created by pouring 5 ml hydrochloric acid (ca. 20%) onto 0.5 g potassium permanganate in a beaker such a chlorine chamber is ready for use after 2 min. 

Tetrammino-magnesium Chloride, [Mg(NH3)4]Cl2.—This compound is produced when magnesium chloride is volatilised in a stream of ammonia gas the ammine condenses as a white meal of composition MgCl2.lNH3. It decomposes quickly with loss of ammonia if exposed to air, but is capable of sublimation in an atmosphere of ammonia. 

If well-dried ammonia gas is passed over freshly sublimed aluminium chloride ammonia is rapidly absorbed, heat is developed, and the whole mass fuses and then gradually solidities as more ammonia is absorbed, leaving a white voluminous powder of composition A1C13.GNH3 or [A1(NH3)6]C13. Hexammino-aluminium chloride is stable at ordinary temperature and is much less hygroscopic than the chloride. It is decomposed by water with formation of aluminium hydroxide, and when heated in dry air is oxidised, yielding the oxide and ammonium chloride. If heated in an atmosphere of dry hydrogen it loses ammonia and passes into diammino-aluminium chloride, [A1(NH3)2]C13.5 Triammino-aluminium chloride obtained in this way by Persoz was not found by Stillmann and Yoder. 

At ordinary temperature and under atmospheric pressure stannous bromide absorbs only 0-6 molecules of ammonia for every molecule of salt, even after standing for forty hours on lowering the temperature, however, to 0° C. and allowing the salt to remain in contact with ammonia gas for twenty-four hours, triammino-stannous bromide, [Sn(NH3)3]Br2, is formed as a yellow powder. At low temperatures stannous bromide and liquid ammonia react, and at —78° C. ammonia is rapidly absorbed, increase in bulk takes place, and addition compounds containing nine and five molecules of ammonia are produced. 

Ammino-ferric Chloride.—Anhydrous, ferric chloride forms hexammino-ferric chloride, [Fe(NH3)s]Cl3, en exposure to ammonia gas. The compound loses" one molecule of ammonia on keeping fix a dry atmosphere at ordinary temperature, giving the pentammine, [Fe(NH3)6]Cl3, and on heating to 100° C. the tetrammino-derivative, [Fe(NH3)4]Cl3, is formed. Further heating causes complete dissociation with formation of ammonium chloride. The addition compounds are not deliquescent and are insoluble in water, but lose ammonia and chlorine when repeatedly washed with water.3... 

When ammonia gas is bubbled through a suspension of the acetate in ethanol, ammonia molecules replace the water, but in liquid ammonia the dinuclear structure is destroyed to give the tetraammine (Scheme 17). Unless kept in an atmosphere of ammonia the tetraammine reverts to the dinuclear ammine adduct.161... 

Formamide is an excellent solvent for many polar organic compounds and for a selection of inorganic salts. It is very hygroscopic and readily hydrolysed by acids or bases. The commercial product frequently contains formic acid, water and ammonium formate. Purification may be effected by passing ammonia gas into the solvent until a slight alkaline reaction is obtained addition of dry acetone then precipitates the ammonium formate. The filtered solution is dried over magnesium sulphate and fractionally distilled under reduced pressure distillation at atmospheric pressure causes decomposition. Pure formamide has b.p. 105 °C/11 mmHg. 

The rate o oxidation o ammonia at atmospheric pressure on single wires and ribbons has been determined as a function of a gas flow rate and catalyst size. In agreement with boundary layer diffusion theory the function rx, where r is the average rate of reaction/unit area, and x is the length of the surface measured in the direction of gas flow, is directly proportional to gas velocity. 

It is known that phosphorus (+5) oxide actively reacts with water vapor. It is an effective chemisorbent of water, and it can be used for drying of gases. Phosphoric acid is formed however, and regeneration is very difficult. It was created as a sorbent on silica with P-oxide nanolayer. It is an active sorbent of water vapor and it is 5-6 times better than initial silica (at a humidity of 70%). It also adsorbs ammonia, and some organic substances. Its name in industry is P-1-3. The sorbents IVS-1 and P-1-3 are used in industry for clearing and stabilization of the gas atmosphere in devices. 

FIGURE 5 Characterization of iron ammonia synthesis catalyst. High-resolution laboratory diffraction indicated a reversible modification of the iron (111) line profile. Under catalytic reaction conditions, a sub-nitride with x = 15-18 is present in addition to the bulk iron matrix. The fitting and assignment of the data were substantiated by observations of the line profile during step changes in the composition of the gas atmosphere. Details and references are given in the text. 

---