Enthalpies of Mixing for Binary Liquid Mixtures of Monocarbonic Acids and Alcohols

1985 ◽  
Vol 40 (9) ◽  
pp. 947-951 ◽  
Author(s):  
R. Haase ◽  
R. Lorenz
Keyword(s):  
Aliphatic Alcohol ◽  
Excess Enthalpy ◽  
Excess Heat Capacity ◽  
Enthalpy Of Mixing ◽  
Liquid Mixtures ◽  
Binary Liquid ◽  
Molar Excess ◽  
Calorimetric Measurements ◽  
Liquid Systems ◽  
Molar Excess Heat Capacity

We present the results of calorimetric measurements of the molar enthalpy of mixing (molar excess enthalpy) H̄E as a function of temperature and composition (described by the mole fraction x of the alcohol) for 18 binary liquid systems consisting of an aliphatic monocarbonic acid (formic, acetic, propionic, butyric, valeric acids) and an aliphatic alcohol (methanol, ethanol, 1-propanol. 2-propanol, 1-butanol, 2-methyl-2-propanol). The experiments cover temperatures between 298.15 K and 318.15 K and the whole range of compositions (usually nearly 40 compositions at each temperature). There is a great variety of behaviour as far as the function H̄E(x) for T= const is concerned. Many systems show endothermic mixing ( H̄E > 0), other systems exothermic mixing (H̄E < 0), again other systems partly endothermic, partly exothermic behaviour. There is one case (acetic acid + 2-methyl-2-propanol) where H̄E(x) changes its sign twice and the molar excess heat capacity exhibits unusually large negative values.

Enthalpies of Mixing for Binary Liquid Mixtures of Acids

1983 ◽  
Vol 38 (12) ◽  
pp. 1400-1401 ◽  
Author(s):  
R. Haase ◽  
H.-J. Jansen ◽  
B. Winter
Keyword(s):  
Acetic Acid ◽  
Formic Acid ◽  
Propionic Acid ◽  
Entire Range ◽  
Excess Enthalpy ◽  
Liquid Mixtures ◽  
Binary Liquid ◽  
Calorimetric Measurements ◽  
Liquid Systems ◽  
C 30

Abstract For the binary liquid systems formic acid + acetic acid, formic acid + propionic acid, and acetic acid + propionic acid, we give the results of new calorimetric measurements of the molar excess enthalpy H̄E at 25 °C, 30 °C, 40 °C, and 60°C, covering the entire range of compositions. H̄E is always positive, increases linearly with the temperature, and is slightly asymmetric with respect to the mole fraction x. The composition at the maximum of the function H̄E(x) is independent of the temperature.

scholarly journals Evaluation of Excess Thermodynamic Parameters in a Binary Liquid Mixture (Cyclohexane +O-Xylene) at Different Temperatures

2010 ◽  
Vol 7 (3) ◽  
pp. 927-934 ◽  
Author(s):  
K. Narendra ◽  
P. Narayanamurthy ◽  
CH. Srinivasu
Keyword(s):  
Excess Enthalpy ◽  
Composition Range ◽  
Liquid Mixture ◽  
Weak Interactions ◽  
Adiabatic Compressibility ◽  
Liquid Mixtures ◽  
Binary Liquid Mixture ◽  
Binary Liquid ◽  
Different Temperatures ◽  
Excess Internal Pressure

The ultrasonic velocity, density and viscosity in binary liquid mixture cyclohexane witho-xylene have been determined at different temperatures from 303.15 to 318.15 K over the whole composition range. The data have been utilized to estimate the excess adiabatic compressibility (βE), excess volumes (VE), excess intermolecular free length (LfE), excess internal pressure (πE) and excess enthalpy (HE) at the above temperatures. The excess values have been found to be useful in estimating the strength of the interactions in the liquid mixtures. Analysis of these parameters indicates that there are weak interactions among the components of the binary mixtures.

Molar excess volumes, isentropic compressions, and isobaric heat capacities of methanol – isomeric butanol systems at 298.15 K

1988 ◽  
Vol 66 (4) ◽  
pp. 713-717 ◽  
Author(s):  
Tsukasa Okano ◽  
Hideo Ogawa ◽  
Sachio Murakami
Keyword(s):  
Hydrogen Bonding ◽  
Concentration Dependence ◽  
Liquid Mixtures ◽  
Heat Capacities ◽  
Excess Volumes ◽  
Pure Liquid ◽  
Excess Functions ◽  
Binary Liquid ◽  
Molar Excess ◽  
Molar Excess Volumes

Molar excess volumes, molar excess isentropic compressions, and molar excess isobaric heat capacities for binary liquid mixtures of methanol with 2-methylpropanol, 2-butanol, and 2-methyl-2-propanol have been determined at 298.15 K. The concentration dependence and magnitude of these thermodynamic functions are quite different from those of the methanol – 1-butanol system, which had been previously determined. Molar excess volumes for two of the present systems are positive over the whole concentration range, except for the 2-methyl-2-propanol system. For the latter system they are negative in the butanol-rich range. Molar excess isentropic compressions of these systems show slightly different concentration dependence from that of the excess volumes, but the order in magnitude resembles that of the excess volumes. Molar excess isobaric heat capacities for all systems are negative and show simple concentration dependence. The minimum values of excess heat capacities are correlated with the magnitude of molar isobaric heat capacities of the pure isomeric butanols. The behavior of these excess functions is discussed with reference to the differences in numbers and strength of hydrogen bonding between the pure liquid and the solution.

Mixing Enthalpies of TbBr3-MBr Liquid Mixtures

2001 ◽  
Vol 56 (12) ◽  
pp. 859-864 ◽  
Author(s):  
L. Rycerz ◽  
M. Gaune-Escard
Keyword(s):  
Mole Fraction ◽  
Composition Range ◽  
Liquid Mixtures ◽  
Entire Composition Range ◽  
Mixing Enthalpy ◽  
Rich Region ◽  
Enthalpies Of Mixing ◽  
Binary Liquid ◽  
Liquid Systems ◽  
Mixing Enthalpies

AbstractThe molar enthalpies of mixing, Δmix Hm in the binary liquid systems TbBr3-MBr (M = Li, Na, K, Rb, Cs) have been m easured with a Calvet-type high-tem perature microcalorimeter over the entire composition range with an accuracy of about 6 %. Mixing of the two liquid components was achieved by using the “break-off am poule” technique. All the investigated systems show negative enthalpies of mixing with a minim um value of approxim ately -1.25, - 8 .3 , -17.0, - 2 0 . 0 and -22.5 kJ mol -1, for M = Li, Na, K, Rb and Cs, respectively. The mixing enthalpy in the TbBr3- LiBr system is positive in the TbBr3-rich region. For all the systems, the enthalpy minimum occurs at mole fraction xTbBr3 ≈ 0.3 - 0.4. The molar enthalpies of form ation Δ formHm (3MBr, TbBr3, 1) for M = Li, Na, K, Rb and Cs at 1113 K (arising from the reaction 3M Br(1) +TbBr3(1) = (3MBr, TbBr3) (1)) are found to be -4 .8 , -31.3, -63.3, -70.3 and -8 1 .2 kJ mol-1 , respectively. The leastsquares coefficients A, B, C, D and E in the equation λ (kJ mol-1) = A + B x + C x2 + Dx3 + Ex4, where A is an interaction param eter and x = xTbBr , are also reported.

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