Gas-Phase Techniques

Manufacture well established well established techniques established for gas phase techniques for liquid phase at developmental stage... 

We have discussed above some of the applications of gas-phase ion thermochemical data to ionic reactions in solution. However the new analytical ion-transfer from solution to the gas-phase techniques have also created an application for these data in the new analytical mass spectrometry. In fact, much of the background knowledge required for this new analytical mass spectrometry, and particularly MALDI and electrospray, is the gas-phase ion chemistry developed for applications... 

Proton Transfer and Electron Transfer Equilibria. The experimental determination used for the data discussed in the above subsections of Section IV.B were obtained from ion-molecule association (clustering) equilibria, for example equation 9. A vast amount of thermochemical data such as gas-phase acidities and basicities have been obtained by conventional gas-phase techniques from proton transfer equilibria,3,7-12-87d 87g while electron affinities88 and ionization energies89 have been obtained from electron transfer equilibria. 

The possibility to grow good-quality thin films at room temperature and normal pressure is the main advantage of SILAR relative to the gas-phase techniques. Moreover, since vacuum systems are not required, SILAR deposition equipment is simple and inexpensive. Similarly, toxic chemicals, such as selenium compounds, which are easier and safer to handle as solutions than as gases, can be more conveniently employed in SILAR. From the environmental point of view, a notable advantage of SILAR is that the system is totally closed and all the chemicals that are used are recyclable. Compared with other solution-phase methods, especially with CBD, an important advantage of SILAR is the facile control over film thickness using... 

Mass spectrometry is traditionally a gas phase technique for the analysis of relatively volatile samples. Effluents from gas chromatographs are already in a suitable form and other readily vaporized samples could be fairly easily accommodated. However the coupling of mass spectrometry to liquid streams, e.g. HPLC and capillary electrophoresis, posed a new problem and several different methods are now in use. These include the spray methods mentioned below and bombarding with atoms (fast atom bombardment, FAB) or ions (secondary-ion mass spectrometry, SIMS). The part of the instrument in which ionization of the neutral molecules occurs is called the ion source. The commonest method of... 

Solution processes for removal of SO2 from effluent gas streams normally require lower absorption temperatures than do gas phase techniques. Thus, of the four listed in Table IV only the Molten Salt Method has the capability of accepting high temperature flue gas without cooling. In all but one of the cases, elemental sulphur is the end product and in the single instance of the Ammoniacal Solution Process, sulphur is a coproduct with ammonium sulphate. This process has been extensively examined and developed in a number of countries, and is chemically interesting because of the unusual redox reaction that is suspected to take place between the products of air oxidation of SO2 absorbed in ammonia solution. Both products, sulphur and ammonium sulphate, are normally saleable commodities. 

Similarly, as spectroscopic techniques have been used to study many long-lived, electrophilic species such as carbocations, acyl and carbox-onium ions, and various onium ions, they have also been used in a number of reports directed to characterization of superelectrophiles. Both condensed and gas phase techniques have been used to study superelectrophilic systems. In the condensed phase, however, superelectrophiles are... 

Over the past several years, the area of gas-phase transition metal ion chemistry has been gaining increasing attention from the scientific community [1-16]. Its appeal is manifold first, it has broad implications to a spectrum of other areas such as atmospheric chemistry, corrosion chemistry, solution organometallic chemistry, and surface chemistry secondly, an arsenal of gas phase techniques are available to study the thermochemistry, kinetics, and mechanisms of these "unusual" species in the absence of such complications as solvent and ligand... 

The authors doubt this kind of processes being found on solution, due to the competition of solvation phenomena with the formation of complexes. Additionally, the solvation would make more difficult the study of chiral selectivity by FTIR, as there would be a broadening of the -OH stretching bands. However, they propose the study of the interactions of methyl lactate with several solvents, using the same gas phase technique. 

Mass spectrometry (MS) is a gas-phase technique in which atoms or molecules present in the spectrometer chamber are ionized, and follow a trajectory through applied electric and magnetic fields which separates them according to their mass/charge ratio. A number of procedures have been developed to enable MS to be used for analysing species in the liquid and solid phases, and are based on species extraction into the gas phase. These include plasma desorption, ion bombardment, thermospray and electrospray ionization, and laser desorption. In this section we concentrate on techniques useful to electrochemistry. 

The Chemistry of Decorating Oxide Surfaces with Metal Complexes -Gas Phase Technique... 

One may apply the gas-phase technique to make large amounts of supported metal oxides by the following procedure. The powder of a metal oxide support may be confined as a fixed bed with the gaseous metal acetylacetonate (sublimed from a source at 180-200°C) transported through the bed by an inert carrier gas at a temperature sufficiently high to cause the reaction (>250°C). The extent of reaction between the metal source and the metal oxide support can be determined by monitoring the composition of pentanedione in the gas phase. The... 

Blackman, et al used the gas-phase technique, also known as atomic layer epitaxy (ALE), to develop controlled loadings of Co on silica using a Co(acac)3 precursor (Fig. 18). By this technique they obtained loadings of Co from 5.7 to... 

By application of the gas-phase technique, element 104 was identified by Zvara in Dubna as the first transactinide element. The arrangement is shown schematically in Fig. 14.15. Element 104 was produced by reaction (14.26), and the experiment was... 

Figure 14.15. Gas-phase technique for investigating the chemical properties of element 104 (schematically).

A theoretical investigation of structural and vibrational properties of the gas-phase molecule U(GH3)3 by density functional methodologies or with a post-Hartree-Fock MP2 perturbative approach has been published. The optimized geometries for U(CH3)3 have been compared with the experimental solid-state structural data for U[CH(SiMe3)2]3.19 A novel gas-phase technique, MPCA, employing the reaction between co-ablated metal ions... 

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