Chemicals ammonium molybdate

Chemical products are produced from technical-grade oxide in two very different ways. Molybdenum trioxide can be purified by a sublimation process because molybdenum trioxide has an appreciable vapor pressure above 650°C, a temperature at which most impurities have very low volatiUty. The alternative process uses wet chemical methods in which the molybdenum oxide is dissolved in ammonium hydroxide, leaving the gangue impurities behind. An ammonium molybdate is crystallized from the resulting solution. The ammonium molybdate can be used either directly or thermally decomposed to produce the pure oxide, MoO. ... 

Chemical deposition of both M0S2 and MoSei has been reported from ammonium molybdate solution [76,77], For the sulphur and selenium sources, thioacetamide and selenosulphate were used, respectively. Ammonium hydroxide was added to the sulphide solution, while an acetic acid/ammonium acetate buffer was used with the selenide solution (pH values were not given). Reducing agents (either hydrazine [76] or sodium dithionite [77]) were added to the baths. Deposition was started at 90-100°C, followed by lowering to room temperature. 

Hydrogen (Takachiho Co., 99.999%) and He (Takachiho Co., 99.999%) were dried by passing them through a Deoxo unit (SUPELCO Co. Oxysorb) and a Linde 13X molecular sieve trap prior to use. NH3 (Takachiho Co., 99.999%) was used without further purification. The alumina-supported molybdena was prepared using a mixture of hexa-ammonium molybdate and y-alumina (Nikki Chemicals Co.) and calcined in air at 823 K for 3 h. 

Some chemical modifiers behave in other ways—they decrease analyte volatility or concomitant volatility—so that concomitants (matrix) are volatilized during the cleaning step. Examples of the first behavior are certain organic acids, such as ascorbic or citric acids, which react with volatile elements, thereby diminishing their volatilities. An example of the second type of behavior is the use of ammonium molybdate, which reacts with phosphate ions to form the highly refractory ammonium molybdophosphate. 

The samples for on-line analysis were taken through a polysulfone membrane [37]. The seven channel automatic analyzer system consisted of six air-segmented continuous flow-wet chemical analyzers (Skalar analytics) to measure the concentration of ammonia with ion selective electrode (Philips IS-570), phosphate with ammonium molybdate at 880 nm, reducing sugar with pHBAH at 410 nm, methionine with Na-nitroprusside at 505 nm, cephalosporin C with... 

Oxo Mo porphyrin complexes, MoO(por) (190), are formed by chemical,736 electrochemical,328 or photochemical599 reduction (through Mo-X homolysis) of trans-MoO(por)X (191) species (Scheme 8). These compounds were fully described in previous reviews.3,330 Borschel and Strahle prepared a violet form of MoOPc (249) from the reaction of Mo(CO)6 and 1,2-dicyanobenzene in a sealed tube (Scheme 11). A square pyramidal structure with an apical oxo group (d(Mo=0) 1.668(6) A) was established.608 A second blue modification, prepared by reacting ammonium molybdate or Mo02C12 with 1,2-dicyanobenzene in a sealed tube, and the interconversion of the two forms, has been reported.530,737... 

Kieselgel 60, Merck 230-400 mesh. Thin-layer chromatography was performed on silica gel (Kieselgel 60 F254, Merck) aluminium-backed plates (0.2 mm thickness) and visualized by UV and/or dipping into a solution of 2.5 g ammonium molybdate and 1 g ceric sulfate in 10 mL sulphuric acid/90 mL water, followed by heating. Purchased from Aldrich Chemical Company, Inc., Milwaukee, WI, USA. 

Catalyst with 12% Mo loading was deposited on silica support via precipitation of metal sulphide from a homogenous solution containing calculated amount of ammonium molybdate ((NH4)Mo7024.4H20), urea, thioacetamide and nitric acid. Reaction was carried out in a water bath shaker kept at 90 C for 3 hours. The slurry was then filtered and the precipitate was dried in oven at 120 C for 14 hours. All chemicals were obtained from Aldrich as AnalaR grade and ultra-pure water was used to prepare the solutions... 

Synthesis of phthalocyanine-2,9,16,23-tetrasulfonic acid aluminum(III) complex 48 (R = -SO3 , M == Al(OH)) 10.73 g (40 mmol) 4-sulfophthalic acid monosodium salt, 1.28 g (24 mmol) ammonium chloride, 24.02 g (400 mmol) urea and 0.185 g (0.15 mmol) ammonium molybdate (all chemicals dried) were intensively mixed and placed in a 250 mL glass vessel under dry inert gas. 2 g (15 mmol) water-free aluminum trichloride (purity 99.99%) was added under inert gas. The mixture was heated at first at 140 °C and then within 30 min with stirring to 190 °C, followed by heating at 210 °C for 24 h under inert gas. The blue-colored reaction product was pulverized, treated for 24 h with 1 M aqueous... 

One step methods. PtRuMo/C catalysts obtained by the impregnation manner revealed that the addition of a relatively small amount of Mo results in an electrocatalyst with a higher activity in CO or methanol electrooxidation than with the PtRu/C system. Moreover, Benker et al studied the effect of molybdenum precursor, and the physico-chemical characterization indicated that only traces of molybdenum were present in the samples when Mo (CO) 6 was used for the synthesis, while ammonium molybdate was an appropriate precursor for the synthesis of PtRuMo/C catalysts. On the other hand, a colloidal method developed by Bonnemann et alP was used to prepare carbon supported PtRuMo nanoparticles and established that this method provided a better tool for synthesizing PtRuMo (1 1 1) nanoparticles deposited on a carbon substrate, being more... 

Malachite Green Reagent Dissolve 50 mg malachite green (final concentration 1 mg/ml) (Ajax Chemicals, NSW, Australia) and 500 mg ammonium molybdate tetrahydrate (final concentration 100 mg/ml) (Ajax Chemicals) in 50 ml of 1 M hydrochloric acid (HCl) followed by filtration through a 0.45 gLm filter. Store the solution at room temperature (22°) in the dark for a maximum of 8 weeks. 

Chemicals containing ammonium molybdate and/or molybdenum oxide are used to reduce the smoke from burning PVC. 

Highly active iron oxide catalyst for ammonia synthesis, obtained by adding the promoter of potassium carbonate, ammonium molybdate, and tungstic acid in two stages. S. S. Lachinov, V. I. Tsarev, and A. Z. Lisitsa (Moscow Mendeleev Chemical Institute). SU 1368028 (1988). 

The ammonium molybdate chemicals must not be in contact with metal components. 

Specific chemical methods can be used to reveal phospholipids, glycolipids, sterols or their esters as well as compounds with quaternary nitrogens or vicinal diols. Particularly useful for many membrane extracts is the reaction of ammonium molybdate with inorganic phosphate released from phospholipids. The phosphomolybdic acid so produced is then reduced to give an intense blue colour. The method can be adapted to a spray reagent or, more often, used to detect as little as 1 jug of phosphorus in scraped samples. 

As early as 1923, Dienert and Wandenbulcke claimed that the silica in the natural waters they examined was not colloidal, and later Roy [1945] and Iler [1955] provided evidence of monomeric silicic acid in dilute aqueous solutions. The development of a simple chemical test for monomeric silicic acid, using acidified ammonium molybdate solution (Alexander et al. [1954]) did much to raise doubts concerning long-established concepts of silica in solution. In addition, the fact that the ionization constants quoted for silicic acid from various sources are in fairly good agreement can be taken as further proof of the existence of the monomeric form in solution (Roller and Ervin [1950] Greenberg [1958]). White et al. [1956] and Krauskopf [1956] have gone so far as to claim that in natural waters, silica is... 

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