Trace gases stability conditions

The difference in conjugation between neutral molecules and their ion-radicals can also be traced for keto-enol tautomerism. As a rule, enols are usually less stable than ketones. Under the equilibrium conditions, enols exist only at a very low concentration. However, the situation becomes different in the corresponding cation-radicals, where gas-phase experiments have shown that enol cation-radicals are usually more stable than their keto tautomers. This is because enol cation-radicals profit from allylic resonance stabilization that is not available to ketones (Bednarek et al. 2001, references therein). 

Liquid anhydrous ammonia is used extensively as a coolant in heat exchange systems because of its chemical stability, low corrosiveness, and high latent heat of vaporization. However, anhydrous ammonia is readily contaminated during handling and storage. The gas chromatographic analysis of trace contaminants (O2, N2, CO, CH4, CO2, and water) in liquid ammonia was described by Mindmp and Taylor. An F M Model 5750 equipped with a Carle Microcavity Thermistor detector was used with dual columns for analysis. Table 9.3 lists the experimental parameters for both columns, which were conditioned for a minimum of 12 h at a temperature of 180°C and a... 

The sequence of inlet gas compositions and how these changes in feed affect the effluent concentrations are shown in Fig. 4.1. Further analysis of these traces allows the calculation of steady-state conversions, NH3 storage under three different conditions, as well as the stability of the stored NH3. Data generated from selected portions of the protocol using Fe-zeolite SCR catalysts will be discussed in the following section for the following conditions 150-550 °C, 60-120 k hr GHSV, and a total NO feed of 150—450 ppm. 

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