Reactions With Gases

Reactions with Gases Hydrogen, Nitrogen, Oxygen... 

Electrodes of this type can, for instance, be used to extract traces of certain metals from seawater or to perform reactions with gases having very low solubility in a given medium. They can also be used to reduce electrochemically or to oxidize particles of materials having very low conductivity. Their efficiency depends on many factors, including the time of contact of the particles with the feeder electrode and the quality of this contact (low resistance to charge transfer during the encounters). 

A series of reactions with gases have been selected for the rapid quantification of many of the major products from the oxidation of polyolefins. Infrared spectroscopy is used to measure absorptions after gas treatments. The gases used and the groups quantified include phosgene to convert alcohols and hydroperoxides to chloroformates, diazomethane to convert acids and peracids to their respective methyl esters, sulfur tetrafluoride to convert acids to acid fluorides and nitric oxide to convert alcohols and hydroperoxides to nitrites and nitrates respectively. 

Refractory materials can be damaged by high temperatures and by reactions with gases, liquids and solids. At high temperatures a brick can contain so much melt phase that its strength becomes too small. In addition abrupt expansion can occur which is caused by the conversion of a mineral in the brick into another allotropic form. 

Sonochemical reactions are strongly affected by ambient gas because the temperature inside the collapsing bubble is in close relationship with the polytropic ratio (Cp/C ) and the thermal conductivity of the gas. In addition, reactions with gases such as Oz, N2, and C02 are directly affected by the high temperatures reached during the collapse of the bubbles. As a consequence, reactive species available for PCP degradation and their rate of production will depend on the nature of the gas. 

Special consideration must be taken when sample transformations involve reactions with gases. For example the decompo-... 

The above ideas indicate that the three following processes have to be considered for the vaporization of a volatile substance from a multicomponent melt (a) diffusion transport of the respective component in the melt (b) surface reaction (i, e. conversion of the component from liquid to gaseous state, possibly including simultaneous reaction with gases from the atmosphere) (c) diffusion transport of vapours through the gas layer. 

Li and its reactions with gases have been extensively studied by AES . A free Li atom cannot undergo an Auger process, since two outer-shell electrons are required. In the... 

Montoya et al. [90] found that density function theory (DFT) is even better than the Hartree-Fock method in modeling graphite reactions with gases, as the former can effectively overcome spin contamination. In a follow-up study... 

Stability against reaction with gases, impurities, catalysts/chemicals ... 

Walker, P.A., Rusinko, E, Austin, L.G. (1963), Carbon Reactions with Gases, Izdatelstvo Inostraimoj Literatury, Moscow. 

Thermal rearrangements Autoclave/pressure reactions Reactions with gases Reactions with solid-siqjpoi reagents... 

ACTIVATED CARBON is a porous CARBON MATERIAL, a CHAR which has been subjected to reaction with gases, sometimes with the addition of chemicals (e.g. ZnCb), before, during, or after CARBONIZATION. 

The surface tension of a liquid alkali metal mixture also shows pronounced deviation from the mean value. The surface tension of liquid cesium (74 N m x 10 ), lies much below that for sodium (197 Nm x 10 ), and since surface tension reflects the attraction between atoms in the liquid, the concentration of cesium in the surface of the liquid metal mixture should be much greater than in the bulk of the liquid. Consistent with this, the surface tension of pure sodium falls rapidly upon addition of cesium, and in the range 40-100% cesium the surface tension is near to that for pure cesium. A similar behavior has been observed for sodium-potassium mixtures. Many chemical reactions of the liquid alkali metals and their mixtures involve reaction with gases, and care must then be exercised in relating reaction rates with bulk composition when it is the surface composition that is the relevant factor. 

As used for low temperature film deposition and substrate processing, a plasma is a partially ionized gas that contains electrons, ions, photons, and neutral species in ground and excited states [13]. Electron impact reactions with gases in the plasma cause molecular dissociation and ionization at low temperature (typically <50 C), thereby promoting reaction rates that are appropriate for surface etching and deposition processes, while ensuring compatibility with temperature-sensitive surfaces such as cellulose. Ion, electron, photon, and neutral radical bombardment onto... 

---