The Effect of the Hydrogen Bond on the Dielectric Constants and Boiling Points of Organic Liquids

1935 ◽  
Vol 57 (4) ◽  
pp. 600-605 ◽  
Author(s):  
W. D. Kumler
Keyword(s):  
Hydrogen Bond ◽  
Dielectric Constants ◽  
Organic Liquids ◽  
Boiling Points

Estimation of heats of vaporization for non associating organic liquids from the boiling points at various pressures

1986 ◽  
Vol 64 (4) ◽  
pp. 635-640 ◽  
Author(s):  
J. Peter Guthrie
Keyword(s):  
Heat Capacity ◽  
Vapor Pressure ◽  
Boiling Point ◽  
Room Temperature ◽  
Quadratic Function ◽  
Organic Liquids ◽  
Heat Of Vaporization ◽  
Boiling Points ◽  
Temperature And Pressure ◽  
Heats Of Vaporization

At any pressure the heat of vaporization can be expressed as a quadratic function of the boiling point at that pressure. A seven parameter equation expressing the simultaneous dependence on boiling point and pressure can be fitted to the data; six pressures from 1 to 760 Torr (1 Torr = 133.3 Pa) were used. ΔHvap = b11 + b12 In (p) + b13p + (b21 + b22 In (p))tbp + (b31 + b32 In (p))tbp2. This relationship served as a guide for developing a relationship between vapour pressure at 25 °C and the calorimetric heat of vaporization, and also a relationship between vapor pressure at 25 °C and the boiling point at some other pressure. Parameters for both these relationships could be derived from the parameters obtained for ΔHvap as a function of temperature and pressure. A third method was developed starting from an equation for vapor pressure and fitting to the heat of vaporization, the heat capacity of vaporization, and at least one t,p point. These methods allow the estimation of the vapor pressure at room temperature from very meager data. The problems of errors in estimated values are discussed.

The effects of pressure on the density, dielectric constant, and viscosity of several hydrocarbons and other organic liquids

1969 ◽  
Vol 47 (6) ◽  
pp. 893-899 ◽  
Author(s):  
D. W. Brazier ◽  
G. R. Freeman
Keyword(s):  
Molecular Structure ◽  
Dielectric Constant ◽  
Carbon Tetrachloride ◽  
Pressure Range ◽  
High Pressures ◽  
Liquid Structure ◽  
Dielectric Constants ◽  
Pressure Effects ◽  
Organic Liquids ◽  
Increasing Temperature

The effects of pressures up to 4 kbar on the density, dielectric constant, and viscosity of n-pentane, n-hexane, n-octane, cyclopentane, methylcyclohexane, and 2,2-dimethylbutane (DMB) were measured at 30 °C. The pressure effects on the viscosities of n-hexane and n-octane were also determined at 0 and 60°. The densities of diethyl ether and cyclopentanone and the dielectric constant of carbon tetrachloride at high pressures are also recorded. The densities of the hydrocarbons increased by 20–30% and the dielectric constants increased by 11–16% as the pressure was increased from 1 to 4000 bars at 30°, but the viscosities increased by 695–2352% over the same pressure range. Carbon tetrachloride froze at 1500 bars at 30°, and cyclopentanone froze at 3500 bars at about 20°. In agreement with earlier work on other liquids, the value of the Clausius–Mosotti function (ε − 1)V/(ε + 2) for the present compounds decreased slightly with increasing pressure. The viscosity at a given pressure decreased slightly with increasing temperature, and temperature effect increased with increasing pressure. In general, the smaller the compressibility of the liquid, the greater was the effect of pressure on the viscosity; DMB was an exception because its viscosity increased abnormally rapidly with pressure. Molecular structure and liquid structure have greater influences on the pressure dependence of viscosity than on that of density or dielectric constant.

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