THE SORPTION OF DIMETHYL ETHER ON ALUMINA

1935 ◽  
Vol 13b (3) ◽  
pp. 133-139 ◽  
Author(s):  
J. Edwards ◽  
O. Maass
Keyword(s):  
Critical Temperature ◽  
Dimethyl Ether ◽  
Critical Pressure ◽  
Monomolecular Layer ◽  
Temperature Range ◽  
Continuous Form

The sorption of dimethyl ether on alumina has been investigated at pressures from 0.5 to 52 atm., the critical pressure, over the temperature range 25–135 °C. The results are comparable to those for the propylene–alumina system. No discontinuity in the sorption accompanies the transition of sorbate from vapor to gas at the critical temperature; this differs from the previous results for the liquid-to-gas change. The initial stages of the sorption involve the formation of a monomolecular layer followed, with increasing pressure, by a multimolecular layer of increasing depth. It is unlikely that condensation to liquid occurs in the pores except at high relative pressures. The increase in critical temperature of such a liquid must be exceedingly great to account for the continuous form of the isobars up to 135 °C.

Critical constants and density dependence of the Lorenz–Lorentz coefficient for germane

1978 ◽  
Vol 56 (9) ◽  
pp. 1140-1141 ◽  
Author(s):  
P. Palffy-Muhoray ◽  
D. Balzarini
Keyword(s):  
Critical Temperature ◽  
Density Dependence ◽  
Experimental Error ◽  
Critical Density ◽  
Coexistence Curve ◽  
Index Of Refraction ◽  
Density Range ◽  
Temperature Range ◽  
Critical Constants

The index of refraction at 6328 Å has been measured for germane in the density range 0.15 to 0.9 g/cm3. The temperature and density ranges over which measurements are made are near the coexistence curve. The coefficient in the Lorenz–Lorentz expression, [Formula: see text], is constant to within 0.5% within experimental error for the temperature range and density range studied. The coefficient is slightly higher near the critical density. The critical density is measured to be 0.503 g/cm3. The critical temperature is measured to be 38.92 °C.

Rate coefficients of hydroxyl radical reaction with dimethyl ether over a temperature range of 257–333 K

2018 ◽  
Vol 706 ◽  
pp. 558-563 ◽  
Author(s):  
Monali Kawade ◽  
Asmita Sharma ◽  
D. Srinivas ◽  
Ankur Saha ◽  
Hari P. Upadhyaya ◽  
...  
Keyword(s):  
Hydroxyl Radical ◽  
Dimethyl Ether ◽  
Radical Reaction ◽  
Rate Coefficients ◽  
Temperature Range

scholarly journals The influence of pressure on the spontaneous ignition of inflammable gas-air mixtures - IV—methane-, ethane-, and propane-air mixtures

1936 ◽  
Vol 154 (881) ◽  
pp. 95-112 ◽  
Keyword(s):  
Critical Pressure ◽  
Spontaneous Ignition ◽  
Lower Range ◽  
Experimental Conditions ◽  
Temperature Range ◽  
Limited Temperature ◽  
Tentative Hypothesis ◽  
Temperature Ranges ◽  
Higher Temperature ◽  
Temperature And Pressure

In previous papers the results of investigations into the influence of varying initial pressures up to 15-20 atmospheres on the spontaneous ignition of mixtures with air of butane, iso -butane, pentane, and hexane were described. On the attainment of a critical pressure, which varied both with the hydrocarbon concerned and the composition of its mixture with air, the ignition points were always found to fall sharply from a higher temperature range above 500°C to a lower range at about 300°C. At pressures just exceeding the critical transition pressures ignition occurred at first only within limited temperature ranges which widened and ultimately merged with increasing pressure. The striking relationship between the behaviours of the hydrocarbons referred to under the experimental conditions and their “knocking” propensities in an engine was also indicated. While the data available were inadequate for drawing any final con­clusion as to the character of the phenomena referred to, a tentative hypothesis was advanced that while ignition in the higher temperature range pertains mainly to the thermal decomponents of intermedially formed compounds, ignition in the lower system occurs when temperature and pressure conditions favour the survival and further oxidation of such bodies, particularly aldehydes.

Estimation of Critical Temperature and Critical Pressure Using Antoine Constants

2015 ◽  
Vol 48 (2) ◽  
pp. 104-106 ◽  
Author(s):  
Katsumi Tochigi ◽  
Satoru Ando ◽  
Kyohei Suginuma ◽  
Hiroyuki Matsuda ◽  
Kiyofumi Kurihara
Keyword(s):  
Critical Temperature ◽  
Critical Pressure

The Direct Determination of the Critical Temperature and Critical Pressure of Normal Hydrogen1

1950 ◽  
Vol 72 (8) ◽  
pp. 3565-3568 ◽  
Author(s):  
David White ◽  
Abraham Solomon Friedman ◽  
Herrick L. Johnston
Keyword(s):  
Critical Temperature ◽  
Critical Pressure ◽  
Direct Determination

Low-temperature storage of mammalian spermatozoa

1957 ◽  
Vol 147 (929) ◽  
pp. 498-508 ◽  
Keyword(s):  
Critical Temperature ◽  
Low Temperatures ◽  
Freezing Point ◽  
Egg Yolk ◽  
Slow Cooling ◽  
Temperature Range ◽  
Low Temperature Storage ◽  
The Media ◽  
Extent Of Damage ◽  
Mammalian Spermatozoa

Experiments in this and other countries on the preservation of spermatozoa at very low temperatures have shown that no mammalian spermatozoa so far examined survive freezing when they are cooled ultra-rapidly from temperatures above freezing point to temperatures of — 79° C or below. Slow cooling and the addition of glycerol to the media in which the spermatozoa are suspended, however, permits survival of the spermatozoa of many species. In different animals, there are marked variations in the resistance of their spermatozoa to freezing and the proportion of spermatozoa which can be revived from very low temperatures may be influenced both by the concentration of glycerol added to the semen and by the composition of the diluting fluid. In experiments with the spermatozoa of the bull, ram, stallion and boar it has been found that during slow cooling to — 79° C there is a critical temperature range between — 15 and — 25° C at which the greatest amount of damage occurs. The rate at which the capacity for motility of the spermatozoa is destroyed within this critical temperature range is considerably reduced by allowing the spermatozoa to stand at 2° C in contact with a medium containing egg yolk and glycerol for 18 h before freezing. The extent of damage in the critical temperature range may also be reduced by cooling the specimens at a rate of 0-25 to 0-5° per second between —15 and —25° C.

scholarly journals SOUND VELOCITY AND SOUND ABSORPTION IN THE CRITICAL TEMPERATURE REGION

1951 ◽  
Vol 29 (3) ◽  
pp. 243-252 ◽  
Author(s):  
W. G. Schneider
Keyword(s):  
Critical Temperature ◽  
Liquid Phase ◽  
Sound Velocity ◽  
Temperature Region ◽  
Temperature Range ◽  
Maximum Value ◽  
Increasing Temperature ◽  
Very High ◽  
High Absorption ◽  
Liquid And Vapor Phases

The velocity and absorption of ultrasound (600 kc.) has been measured throughout the critical temperature region of sulphur hexafluoride. Measurements were carried out for the coexisting liquid phase and vapor phase below Tc, and for the supercritical gas, and simultaneously, observations of the meniscus behavior in the neighborhood of Tc were made. The sound velocity for both liquid and vapor phases below Tc decreased with increasing temperature and became equal at Tc, the velocity at this point being 121.5 m. per sec. In the temperature range from 0.6° below Tc to Tc the velocity in the vapor was greater than that in the liquid. A very high absorption of sound was observed, having a maximum value at Tc and extending over a temperature range of approximately 1°. In the temperature range from Tc to 0.6° below Tc, the absorption in the liquid phase was greater than that in the vapour.

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