Ammonia metal salt effects

Other investigations of the porosity of activated carbon cloth explored the effects of impregnation with certain transition metal salts and oxo-complexes (Freeman etal., 1989) and of activation in ammonia (Tomlinson etai, 1993). In the latter case it was found that ammonia reacts with the viscose rayon chars to form various nitrogen-containing microporous products. An early study by Barton and Koresh (1983) had also demonstrated that the pore structure of carbon cloth and its affinity for water vapour can be modified by HN03 activation. 

Direct reaction is commonly effected in a mixed-solvent system, frequently by mixing an ethanolic solution of the jS-keto imine with an aqueous solution of the metal salt. An ammoniacal metal salt solution can be used to prevent hydrolysis and to shift the chelation equilibrium (see synthesis 60). This practice can be very effective, but it has the disadvantage of adding extraneous ions furthermore, the high concentration of ammonia may result in an undesired amine exchange. ... 

This method can be applied to the preparation of single catalysts or, by coprecipitation, to multi-component catalysts. Hydrous oxides, sulphides, carbonates and phosphates can be used. After precipitation, the catalyst must be washed free of impurities which might have an adverse effect on the final catalytic properties. The presence of these impurities can be minimised by the use of dilute solutions. An alternative is the mixing of a metal salt with ammonia or an ammonium salt. Any ammonium nitrate remaining in the precipitate is readily removed by washing because of its high water solubility, and the last traces can be eliminated by calcination. 

S. Kasaoka and H. Nanba, "Effect of Alkali Earth Metal Salt Deposition on Catalytic Activity of Vanadium Pentoxide/Titanium Dioxide in Nitric Oxide Reduction with Ammonia", Nenryo Kvokaiski. Japan, 1984, i(6), 403-412. 

An informative and amusing background to that unique material, camphor, has appeared. Its preparation by Oppenauer oxidation of the epimeric borneols occurs without epimerization. Epimerization does not occur in the presence of potassium t-butoxide in t-butyl alcohol, but it does with potassium isopropoxide in propan-2-ol." The reaction of camphor with phosphoric acid yields a complex mixture of m- and p-cymenes, 3,4-dimethylethylbenzene, 1,2,3,4-and 1,2,3,5-tetramethylbenzene, fenchone, carvenone, and carvacrol. A very detailed examination of the metal-ammonia reduction has revealed an intermediate camphor analogue of pinacol formed by association of a camphor anion radical with the metal cation. This intermediate was isolated and characterized. Other effects are discussed, such as that of adding a large excess of metal salt (LiBr, KBr, or NH Cl)." ... 

Opatowski Process. A process for the extraction of BeO from siliceous ores. The ground ore is mixed with NH4HSO4 and water and heated to 95 C to dissolve metal salts. Mn is oxidised using NH4S2O8, and ammonia treatment precipitates the metals as hydroxides. After separation, treatment with NaOH dissolves the beryllia as Na2Be02, which is hydrolized to Be(OH), which on heating to 250 C, decomposes to beryllia, BeO. The process is effective for concentrations of BeO in the ore of 51%, and the (NH4)2S04 formed is recycleable. (J. Opatowski, Canadian Pat. 663 776 1962). 

Metal ions can act as Lewis acids (i.e., electron acceptors) toward water molecules that serve as Lewis bases (i.e., electron donors) and toward other Lewis bases. This can have a profound effect on the solubility of a metal salt. For example, AgCl(s) dissolves in aqueous ammonia because of the Lewis acid-base interaction between Ag (aq) and NH3(aq)... 

The effect of alkali metal salt as promoter can be fully shown after it is well reduced under the conditions of ammonia s3mthesis. The study by Forni et showed that cesium can prevent metal sintering and increase the dispersion of active components. When activated carbon is used as support, Kowalczyk Z et al. considered that the promoting role mainly occur in contact points between ruthenium and cesium adsorbed on activated carbon surface because parts of cesium salt are reduced to metal cesium. As alkali metals are unstable in ruthenium catalysts, (Cs - - O) groups also exist, which mainly are distributed on the surface of ruthenium particles. The promotional effect of Cs + O groups is relatively lower when activated carbon is the support, while they play a major role when MgO is used as support, although with a lower extent than that in Cs-Ru/AC. ... 

Chelating agents that contain amino and carboxyl groups mask metal ions effectively. Chemical compounds of this type are nitrilotriacetic add (NTA), ethylene-diaminetetraacetic add (EDTA), diethylenetriaminepentaacetic add (DTPA), and hydroxyethylethylenediaminetriacetic add (HEEDTA). Other complexing agents include the soluble salts of oxalic add, dtric acid, tartaric acid, gluconic add, amines, and ammonia. 

Actually, the following experimental conditions should be optimized to fabricate the present type weU-defined hybridized NCs, except for selected combination of 7t-conjugated polymer and a noble metal, concentration of metal-salt solution, initial pH control by adding base like ammonia, reaction temperature and time, stirring method, and VIS light intensity [53,54]. Recently, it has become apparent that ultrasonic wave irradiation is much more effective than mechanical stirring [121],... 

The hydrochloric acid evolved is extremely corrosive, necessitating the injection of a basic compound, such as ammonia, into the overhead lines to minimize corrosion damage. Salts and evolved acids can also contaminate both overhead and residual products, and certain metallic salts can deactivate catalysts. A thorough discussion of the effects of salt on crude processing is included in a manual on impurities in petroleum [14 ]. 

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