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Methods for the Determination of Organics
Published in V. Dean Adams, Water and Wastewater Examination Manual, 2017
Concentrated Sulfuric Acid Catalyst: Add 22 g of silver sulfate (Ag2SO4) to a full 9 lb bottle of cone. H2SO4. Allow 1–2 days for dissolution with stirring and then attach the bottle to an acid repipet. Set the repipet to deliver 30.0 mL. Silver sulfate catalyst is used to more effectively oxidize straight chain organic compounds.
Dynamic disorder in the high-temperature polymorph of bis[diamminesilver(I)] sulfate—reasons and consequences of simultaneous ammonia release from two different polymorphs
Published in Journal of Coordination Chemistry, 2021
Laura Bereczki, Lara Alexandre Fogaça, Zsolt Dürvanger, Veronika Harmat, Katalin Kamarás, Gergely Németh, Berta Barta Holló, Vladimir M. Petruševski, Eszter Bódis, Attila Farkas, Imre Miklós Szilágyi, László Kótai
Accordingly, in an inert atmosphere, elementary sulfur (m/z = 32) was detected in a minor amount. The ratios of intensities of the peaks of NH3 and H2O, and their fragments (m/z = 18(OH2)), m/z = 17 (NH3, OH) and m/z = 16(NH2, O)), are different in air and an inert atmosphere (Figures 10 and 11). The peak m/z = 18 belongs only to H2O+ while to the intensity of m/z = 17 peak either NH3+ or OH+ ions can contribute. Therefore, the ratio of the m/z = 18 and 17 peak intensities can give some information about the ratio of parent (NH3+ and H2O+) ions [42]. In air, the oxidation of ammonia (increasing the amount of water and decreasing the ammonia) with oxygen is expected. However, the intensity of the m/z = 18 peak (H2O) is smaller than that of the m/z = 17 peak (OH+ + NH3+), which means that the main component of the m/z = 17 peak is NH3+. In argon, however, the intensity of the m/z = 18 peak is closer to the intensity of the m/z = 17 (OH or NH3) peak, so the contribution of ammonia to the peak of m/z = 17 is less than in air. These results can be attributed to the ammonium sulfite decomposition reaction in a solid phase quasi-intramolecular redox reaction with the formation of water, nitrogen oxides and elemental sulfur [42], which have influence on the intensity of water/ammonia parent ions in the evolved gas analyses. A very weak m/z = 44 peak was observed only in air, so it can be attributed to the formation of N2O, while the peaks at m/z = 14 (N), 28 (N2), or 16 (O) in experiments in an air atmosphere could not be evaluated because of the components of air (N2, O2). The only NOx type oxidation product formed in both atmospheres was NO. It is highly possible that the decomposition of the 1-LT polymorph is accomplished with ammonia loss and simultaneous ammonia oxidation by the sulfate ion and the formation of S(IV) species (ammonium sulfite), whereas the decomposition of the 1-HT polymorph, which has no strong hydrogen bond systems, proceeds without the oxidation of ammonia. Since the polymorphic transition temperature of 1-LT is lower than its decomposition peak temperature, the 1-HT polymorph can form and decompose into ammonia and silver sulfate as was observed. Silver sulfate has an orthorhombic-hexagonal phase transition (from ordered Fddd to disordered P63/mmc) at 426 °C, which is followed by melting at 658 °C [21] both in an inert atmosphere and in air.