Oxygen inversion temperature

At very low oxygen pressures, Bevan and Anderson found that the graphs of conductivity against inverse temperature yield an activation energy of a few hundredths of an electron volt, and that the conductivity becomes independent of oxygen pressure. This activation energy is similar to that for ionization of the electrons from the interstitial zinc atoms, as obtained from low temperature and single-crystal measurements. This may indicate that the surface effects become unimportant at very low pressures. 

Figure 5. PBS etch rate vs inverse temperature in an oxygen plasma.

Figure 4 The ionic current plot as a function of temperature at different oxygen partial pressures (0.05, 0.30, and 1.00 atm). The inset is a plot of the simulated conductivity compared to the EIS experiment [115] (in log(o) in Sm- ) as a function of inverse temperature (in 1000/7). Reprinted from Reference [119], copyright 2008, with permission from Elsevier.

Figure 4.18 Tracer diffusion coefficients of oxygen, D, in YSZ as a function of inverse temperature. A, Dg single costal 9.5 mol%Y2O3-doped [261] B, Dg single C7Stal 9.5 mol% Y2O3-doped [275] C, D g single costal 6.9 mol% Y2O3-doped [275] D, Dj compacted nanocrysta 6.9 mol% Y2O3-doped [275] E, Dj compacted nanocrystal 8 mol% Y2O3-doped [277] F,...

Combes et al. reported investigations of the equilibrium constant of reaction (1.2.4) in the molten KCl-NaCl equimolar mixture [119, 180, 240], The experimental routine consists in addition of a weight of O2- donor to the melt afterwards the equilibrium e.m.f. of the cell with the indicator oxygen electrode (NilNiOlZr02) is measured and the e.m.f. values are determined at partial pressures of water vapour from 0.0013 to 0.011 atm. The calculations of the equilibrium constant of reaction (1.2.4), performed using the obtained e.m.f. values, show that in the temperature range 737-817 °C the dependence of the pK of the equilibrium (1.2.4) upon the inverse temperature is expressed by the following equation ... 

Bergbreiter " synthesized smart phosphine ligands 26 and 27 (Figure 6) from an ethylene oxide-propylene oxide-ethylene oxide triblock co-polymer that possesses a property termed inverse temperature-dependent solubility. This means that at low temperature, the phosphines and their rhodium complexes are soluble in water through the formation of hydrogen bonds between oxygen atoms and water molecules, but, on heating above the critical-temperature cloud... 

Hydroalkoxylation of alkynes, or the addition of alcohol to alkynes, is a fundamental reaction in organic chemistry that allows the preparation of enol ethers and a variety of oxygen-containing heterocycles such as furan, pyran, and benzofuran derivatives. Bergbreiter et al. found that a Mnear poly-(A-isopropylacrylamide) (PNIPAM) polymer exhibited inverse temperature solubility in water (i.e., soluble in cold water but insoluble in hot water). A recoverable homogeneous palladium catalyst was prepared based on the polymer. The PNIPAM-bound Pd(0) catalyst was effective for the reaction of 2-iodophenol with phenylacetylene in aqueous THE media to give the target product... 

Figure 2. Plot of the self-

Find the inversion temperature for oxygen at a pressure of 4.05 MPa. Use the equation of state developed for oxygen by Van Itterbeek and Verbeke, " namely,... 

The most puzzling thing about the epinine data in Table XIII is that as the temperature is decreased the amount of hydroxylation reaction in the presence of ascorbate actually increases, i.e., there is a reverse-temperature effect. This result can be explained if one makes the further assumption that the postulated epinine-hydroperoxide intermediate is unstable at 35°C., so that the steady-state concentration of the intermediate is somewhat lower at 35°C. than at 22°C. The inverse temperature effect for dopamine hydroxylation, not seen in the 22°C. to 35°C. range, but apparent in the 35°C. to 49°C. range, could be explained in the same way if the dopamine-peroxide intermediate were relatively stable at 35°C. but unstable at 49°C. At that high temperature, however, enzyme inactivation may play a role. An additional factor which may contribute to these inverse rate-temperature effects is the decreased solubility of one of the substrates, oxygen, at higher temperatures. 

The solubihty of a gas in water is affected by temperature, total pressure, the presence of other dissolved materials, and the molecular nature of the gas. Oxygen solubihty is inversely proportional to the water temperature and, at a given temperature, directly proportional to the partial pressure of the oxygen in contact with the water. Under equihbrium conditions, Henry s law apphes... 

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