Gas titration

Current views on the surface enrichment of one component over another in alloy systems are, surprisingly, more a consequence of gas titration and Auger electron spectroscopy than XPS and UPS. There is little doubt, however, that looking to the future XPS will provide important clues regarding the mechanism of bimetallic catalysts, the significance of promoters. 

Further experiments (159), including gas titrations, reactivity studies, and spectroscopic evidence, led to the formulation of the intermediate, earlier postulated (158) to be an oxygenated cobaltocene adduct, as the organic peroxide structure 63, in which the dioxygen bridge once again links the cyclopentadiene ligands in an exo fashion. This complex... 

See also - chemical potential, -> electrolytic domain, - gas titration coulometric, - Wagner equation. 

The stoichiometry is being confirmed in an independent way by gas titrations. A stream of ozone is mixed with either nitric oxide or nitrogen dioxide, and enough... 

The characterization of supported metal catalysts is a matter of some complexity and supported bimetallic catalysts even more so. Nevertheless the development and application of methods for determining catalyst structure is essential for an understanding of why the performance of a selected combination of metal(s) and support varies as a function of preparative variable, activation procedure, reaction conditions, or time. Although some aspects of catalyst structure can be routinely determined, the basic measurement of absolute metal dispersion by selective chemisorption/gas titration is still the subject of many publications and the necessity of cross-checking by instrumental methods is generally appreciated. The characterization of supported metal catalysts also involves some less accessible properties, e.g., the sites available on crystallites as a function of size, high-temperature... 

The semi-automatic gas titration device is a useful tool for measuring the rate, as well as the extent, of a gas consuming reaction. In terms of measuring the rate, or completeness, of a gas consuming reaction, this device is a versatile, precise, semi-automatic, time saving tool far exceeding the capabilities of a mercury manometer equipped with a meter stick. 

In principle, the semi-automatic gas titration device works by monitoring the partial vacuum created by a chemical reaction that consumes a gaseous substrate within a closed system.. 2 As the reaction progresses, the consumed gas is continually replenished in small uniform aliquots through a parallel set of solenoids connected to the reaction vessel and to a source of fresh reactant gas. 

Figure 1. Schematic of the semi-automatic gas titration device, depicting the arrangement of the electronic manometer, solenoids, and manifold.

Figure 3. Additional components of the semiautomatic gas titration device, (a) Ballast tank used for adjusting and maintaining the pressure during a reaction. Continued on next page.

It is possible, in some cases, to test the correlation between the probe signal and atomic concentrations by the technique of gas titration. For instance, in a calorimeter probe detection of hydrogen atoms, it was determined by comparison with H + NOCl titrations that the electrical power required to balance the probe resistance was equivalent to the full recombination energy of the hydrogen atom flow [33]. 

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