Gases Revisited

These properties of gases were introduced in Section 4.1  

Gases expand to fill their containers uniformly. 

All gases have low densities compared with those of liquids and solids. 

A gas exerts constant, uniform pressure in all directions on the walls of its container. 

These properties are accounted for in the kinetic molecular theory (Section 4.2), which includes the ideal gas model. This model describes the particulate behavior of 

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Phinney, D., Tennyson, J. Frick, U. 1978. Xenon in the C02-well gas revisited. Journal of Geophysical Research, 83, 2313—2319. 

Phinney D (1972) Ar, Kr, and Xe in terrestrial materials. Earth Planet Sci Lett 16 413-420 Phinney D, Tennyson J, Frick U (1978) Xenon in CO2 well gas revisited. J Geophys Res 83 2313-2319 Podosek FA, CassenP (1994) Theoretical, observational, and isotopic estimates of the lifetime of the solar nebula. Meteoritics 29 6-25... 

Plyasova LM, Molina lY, Gavrilov AN, Cherepanova SV, Cherstiouk OV, Rudina NA, Savinova ER, Tsirlina GA. 2006. Electrodeposited platinum revisited tuning nanostructure via the deposition potential. Electrochim Acta 51 4477-4488. 

Inderwildi, O.R., Jenkins, S. J., and King, D.A. 2008. Fischer-Tropsch mechanism revisited Alternative pathways for the production of higher hydrocarbons from synthesis gas. J. Phys. Chem. C 112 1305-7. 

The neutral and acid-catalysed mechanisms of hydrolysis of formamide, HCONH2, have been revisited and a comparison made between ab initio, semiempirical and DFT results Ab initio MO calculations on the alkaline hydrolysis of para-substituted acetanilides (135) in the gas phase have shown that the activation energy depends on the nature of electron-withdrawing groups (e.g. X = NO2, CN, Cl) but is invariant for electron-donating groups (X = NH2, OMe). ... 

A very old gas-solid bromination of tyrosine (280) [97] has been revisited and it gave a quantitative yield for the reaction of rac-280 [22]. The doubly bromi-nated hydrobromide rac-281 is spectroscopically pure after removal of included gases at 50 °C in a vacuum. Quite spectacular is the specific and quantitative waste-free gas-solid tetrabromination of tetraphenylethylene (282), which shows some signs of autocatalysis and requires rotation of the flask around a horizontal axis at room temperature for 12 h as the reactant and product gases require mixing [60]. The isomer-free tetrabromide 283 is an attractive starting point for dendrimer syntheses and inclusion studies (Scheme 40). Also 4-bro-mo antipyrin hydrobromide is quantitatively obtained from antipyrin(hydro-bromide) and bromine vapor [22]. 

The question of methanol protonation was revisited by Shah et al. (237, 238), who used first-principles calculations to study the adsorption of methanol in chabazite and sodalite. The computational demands of this technique are such that only the most symmetrical zeolite lattices are accessible at present, but this limitation is sure to change in the future. Pseudopotentials were used to model the core electrons, verified by reproduction of the lattice parameter of a-quartz and the gas-phase geometry of methanol. In chabazite, methanol was found to be adsorbed in the 8-ring channel of the structure. The optimized structure corresponds to the ion-paired complex, previously designated as a saddle point on the basis of cluster calculations. No stable minimum was found corresponding to the neutral complex. Shah et al. (237) concluded that any barrier to protonation is more than compensated for by the electrostatic potential within the 8-ring. 

The nanostructured interface of this particular PPE/SAN/SBM blend, with a highly diffusive, elastomeric, discontinuous coverage and five different polymers is likely to easily create thermodynamic instabilities as a result of the gas transport between the phases [81, 82], Subsequently, nucleants can be formed which finally lead to cell growth in the SAN phase. In order to describe more precisely these effects induced by the nanostructured interface, we will revisit the gas solubility of the individual phases (Fig. 20). 

The relationship between polymer structure and membrane permeation was discussed in detail in Chapter 2 and is revisited only briefly here. Permeability can be expressed as the product DtKi of two terms. The diffusion coefficient, D, reflects the mobility of the individual molecules in the membrane material the gas sorption coefficient, Kt, reflects the number of molecules dissolved in the membrane material. Thus, Equation (8.3) can also be written as... 

Another interesting result obtained in experiments on these ratios of rate constants is the lack of the dependence of the ratio on the nature of the gas collisionally deactivating the vibrationally excited ozone isotopomer [46]. Different mechanisms have been postulated for the collisional deactivation, including the energy transfer mechanism used here and most commonly used elsewhere, and a chaperon mechanism in which the third-body collision partner forms collision complex with the Q or with the Q2 prior to the recombination step. Recently the chaperon mechanism was revisited for ozone formation, analyzing pressure and temperature dependent data on the recombination rate [47]. Since the ratios of rate... 

Lazarov O, Morfini GA, Lee EB, Farah MH, Szodorai A, DeBoer SR, Koliatsos VE, Kins S, Lee VM, Wong PC, Price DL, Brady ST, Sisodia SS (2005) Axonal transport, amyloid precursor protein, kinesin-1, and the processing apparatus revisited. J Neurosci 25(9) 2386-2395 Lee AC, Harris JP (1999) Problems with the perception of space in Parkinson s disease. Neuroophthalmology 22 1-15... 

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