Thermal diffusion of aqueous alcohols

1989 ◽  
Vol 67 (5) ◽  
pp. 867-870
Author(s):  
Ashis Kumar Mukherjee ◽  
S. K. Sanyal
Keyword(s):  
Aqueous Solutions ◽  
Temperature Coefficient ◽  
Thermal Diffusion ◽  
Soret Coefficient ◽  
Local Entropy ◽  
Solvent Interactions ◽  
Solvent Water ◽  
Heat Of Transport ◽  
Sintered Glass ◽  
Experimental Values

The thermal diffusion of aqueous solutions of methanol, ethanol, propan-1-ol, butan-1-ol, ethan-1,2-diol, andpropan-1,2-diol contained in the pores of a sintered glass disc (of porosity G4) has been studied. The Soret coefficient (σ) and the heat of transport [Formula: see text] values are reported in the temperature range of 25–40 °C. The heat capacities of transport are ascertained at 30 °C from the temperature coefficient of heat of transport values. The results are explained on the basis of changes in local entropy in the solvent (water), arising out of solute–solvent interactions. Correlations of the observed experimental values with certain relevant thermodynamic parameters, taken from the literature, have also been sought, with encouraging results. Keywords: thermal diffusion, heat of transport, entropy of hydration.

Heat of transport and heat capacity of transport of some aqueous electrolytes

1988 ◽  
Vol 66 (3) ◽  
pp. 435-438
Author(s):  
S. K. Sanyal ◽  
Ashis K. Mukherjee
Keyword(s):  
Heat Capacity ◽  
Aqueous Solutions ◽  
Thermal Diffusion ◽  
Aqueous Electrolytes ◽  
Heat Of Transport ◽  
Sintered Glass ◽  
A Cell ◽  
Glass Diaphragm

The thermal diffusion of aqueous solutions of NaCl, KCl, MgCl2, BaCl2, MgSO4, and CuSO4 (0.05 m) contained in the pores of a sintered glass diaphragm has been studied. A cell is designed and fabricated for this purpose, and the resulting heat of transport values are compared with those available from the literature and obtained by using independent techniques.

Heats of transport of some aqueous nonelectrolytes

1986 ◽  
Vol 64 (4) ◽  
pp. 717-719
Author(s):  
A. K. Murkherjee ◽  
S. K. Sanyal
Keyword(s):  
Temperature Gradient ◽  
Aqueous Solutions ◽  
Thermal Diffusion ◽  
Hydrophobic Hydration ◽  
Heat Of Transport ◽  
Sintered Glass ◽  
Glass Disc

The thermal diffusion of aqueous solutions of glucose, sucrose, ethylacetate, and 1,4-dioxan (0.1 m) contained in the pores of a sintered glass disc (or porosity G4), which is subjected to a temperature gradient, has been studied. The resulting heat of transport data have been interpreted, in terms of local changes in entropy in the solvent brought forth by the presence of the solutes, and correlated to the hydrophobic hydration effects.

Thermal Diffusion of Weak Electrolytes III. The Soret Coefficients of Normal Carboxylic Acids

2000 ◽  
Vol 214 (1) ◽  
Author(s):  
L. Domonkos ◽  
J. Liszi
Keyword(s):  
Formic Acid ◽  
Aqueous Solutions ◽  
Carboxylic Acids ◽  
Thermal Diffusion ◽  
Soret Coefficient ◽  
Conductometric Method ◽  
New Model ◽  
Weak Electrolytes

A conductometric method is described and applied for the determination of the Soret coefficient of normal carboxylic acids in aqueous solutions in order to check a new model described in our previous papers. The Soret cell originally developed by Agar and Turner was applied with only minor modifications. The results show that the deviations between the measured and calculated Soret coefficients are lower than 2.5% except for formic acid (33% in average).

Thermal diffusion with hydrolysis in aqueous solutions of sodium carbonate

1991 ◽  
Vol 69 (10) ◽  
pp. 1584-1588 ◽  
Author(s):  
Hui Lü ◽  
Derek G. Leaist
Keyword(s):  
Steady State ◽  
Aqueous Solutions ◽  
Thermal Diffusion ◽  
Sodium Carbonate ◽  
Soret Coefficient ◽  
Mixed Electrolytes ◽  
Cold Plate ◽  
Aqueous Sodium ◽  
Aqueous Sodium Carbonate ◽  
Nonisothermal Conditions

A conductimetric technique is used to measure thermal diffusion in aqueous solutions of sodium carbonate. In dilute solutions hydrolysis produces significant amounts of sodium bicarbonate and sodium hydroxide: Na2CO3 + H2O = NaHCO3 + NaOH. The applied temperature gradient causes the various solutes to migrate to the cooler parts of the solution. NaOH is found to diffuse more rapidly than NaHCO3, leading to the accumulation of excess NaOH (relative to NaHCO3) at the cold plate. Binary Na2CO3(m) + H2O mixtures therefore separate into ternary Na2CO3(m1) + NaOH(m2) + H2O mixtures under nonisothermal conditions. The steady-state molality gradients dm1/dT and dm2/dT and the ternary heats of transport of aqueous Na2CO3 and NaOH are reported. Key words: aqueous sodium carbonate, hydrolysis, mixed electrolytes, Soret coefficient, thermal diffusion.

The thermo-osmosis of gases through a membrane I. Theoretical

1952 ◽  
Vol 210 (1102) ◽  
pp. 377-387 ◽  
Keyword(s):  
Temperature Gradient ◽  
Diffusion Process ◽  
Temperature Coefficient ◽  
Thermal Diffusion ◽  
Stationary State ◽  
Pressure Ratio ◽  
Irreversible Processes ◽  
Heat Of Solution ◽  
Heat Of Transport ◽  
Thermal Diffusion Process

The process of thermo-osmosis is the passage of a fluid through a membrane due to a temperature gradient. Under suitable conditions it gives rise to a stationary difference of pressure. The thermo-osmosis of a gas through a membrane in which it is slightly soluble is due partly to the temperature coefficient of its solubility and partly to the existence of a thermal diffusion process inside the membrane. A theory is developed on the basis of Onsager’s treatment of irreversible processes and leads to equations giving the rate of permeation and the pressure ratio at the stationary state. The magnitude of the effect depends on the algebraic sum of the heat of solution and the heat of transport within the membrane.

The metachor as a characteristic of the association of electrolytes in aqueous solutions

1984 ◽  
Vol 49 (5) ◽  
pp. 1061-1078 ◽  
Author(s):  
Jiří Čeleda ◽  
Stanislav Škramovský
Keyword(s):  
Aqueous Solutions ◽  
Apparent Volume ◽  
Solutions Of Electrolytes ◽  
Molal Volumes ◽  
The Difference ◽  
High Concentrations ◽  
Experimental Values ◽  
Suitable Characteristic ◽  
Association Of Ions ◽  
Very High

Based on the earlier paper introducing a concept of the apparent parachor of a solute in the solution, we have eliminated in the present work algebraically the effect which is introduced into this quantity by the additivity of the apparent molal volumes. The difference remaining from the apparent parachor after substracting the contribution corresponding to the apparent volume ( for which the present authors suggest the name metachor) was evaluated from the experimental values of the surface tension of aqueous solutions for a set of 1,1-, 1,2- and 2,1-valent electrolytes. This difference showed to be independent of concentration up to the very high values of the order of units mol dm-3 but it was directly proportional to the number of the free charges (with a proportionality factor 5 ± 1 cm3 mol-1 identical for all studied electrolytes). The metachor can be, for this reason, a suitable characteristic for detection of the association of ions and formation of complexes in the solutions of electrolytes, up to high concentrations where other methods are failing.

scholarly journals The influence of temperature on the absorption of water by seeds of hordeum vulgare in relation to the temperature coefficient of chemical change

1912 ◽  
Vol 85 (582) ◽  
pp. 546-553 ◽  
Keyword(s):  
Hordeum Vulgare ◽  
Aqueous Solutions ◽  
Temperature Coefficient ◽  
Chemical Change ◽  
Experimental Conditions ◽  
Influence Of Temperature ◽  
Suitable Medium ◽  
Influence Of Temperature On

Attention has previously been directed by one of us to the existence of a differential septum enclosing the seeds of Hordeum (barley). When the seeds are immersed in aqueous solutions of most electrolytes, and of many non-electrolytes, this covering behaves as a very efficient differential septum, water alone entering the seeds under the attractive influence of the finely granulated contents. The rate at which the water enters is considerably affected if substances are dissolved in it, being increased by some and diminished by others; it is also markedly dependent on the temperature of the water or solution in which the seeds are immersed. Variations of the rate at which water enters with alterations of the experimental conditions are presumably due mainly to changes in the water, and the seeds of Hordeum would thus appear to be a very suitable medium for the investigation of the nature of the changes produced in water by the presence of dissolved substances or by alterations of temperature.

Numerical Analysis of Thermal-Solutal Convection in Heterogeneous Porous Media

2005 ◽  
Vol 73 (1) ◽  
pp. 21-25 ◽  
Author(s):  
Charles-Guobing Jiang ◽  
M. Ziad Saghir ◽  
M. Kawaji
Keyword(s):  
Porous Media ◽  
Thermal Diffusion ◽  
Soret Effect ◽  
Heterogeneous Porous Media ◽  
Soret Coefficient ◽  
Solutal Convection ◽  
Coefficient Distribution ◽  
Separation Ratio ◽  
Diffusion In Porous Media ◽  
Vertical Cavity

Thermal diffusion, or Soret effect, in porous media is mathematically modeled with the Firoozabadi model based on non-equilibrium thermodynamics. The Soret effect in a binary mixture is investigated in a vertical cavity with heterogeneous permeability, where natural convection can occur. The thermo solutal convection with heterogeneous permeability was studied in terms of flow pattern, concentration distribution, component separation ratio, and Soret coefficient distribution. A consistent analysis was conducted and it is concluded that the Soret coefficient of thermal diffusion in porous media strongly depends on the heterogeneity of permeability.

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