Measurement of Molecular Weight in Organic Solvents

Taylor, G.; Hall, Mary Beth

doi:10.1021/ac60055a005

Cited by 15 publications

(3 citation statements)

References 12 publications

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“…Thermometric determinations of molecular weights under quasi-isopiestic conditions have been carried out by several workers with systems of non-volatile solutes in various volatile solvents. [3][4][5][6][7][8][9] In the various methods used, a steady-state temperature above the ambient temperature is obtained in a partially isolated solution phase ex-posed to the solvent vapor in air. The temperature rise of the solution caused by the vapor condensing on its surface is the basis of the determination.…”

Section: Introductionmentioning

confidence: 99%

A Thermometric Method for Thermodynamics Studies and Molecular Weight Determinations in Solutions

Higuchi¹,

Schwartz²,

Rippie³

et al. 1959

J. Phys. Chem.

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Section: Introductionmentioning

confidence: 99%

A Thermometric Method for Thermodynamics Studies and Molecular Weight Determinations in Solutions

Higuchi¹,

Schwartz²,

Rippie³

et al. 1959

J. Phys. Chem.

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“…At three times the thermistor diameter, the drop appeared almost ready to fall from the bead. Since it has already been demonstrated by a number of workers (3,4,11,22,23) and verified by the authors that the results are quite independent of the drop size in the concentration range of interest, a value for the drop diameter of twice the thermistor diameter was assumed. In the thermodynamic efficiency calculations when the drop diameter was assumed to be three times the thermistor diameter, the change in the calculated thermodynamic efficiency was very slight.…”

Section: Resultsmentioning

confidence: 87%

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14] have utilized the method of Hill (Ref. 15) to measure either vapor pressure differences or, from these differences, molecular weights of solutes.…”

Section: )mentioning

confidence: 99%

Thermoelectric vapor-pressure osmometry

Adicoff¹,

Murbach²

1967

Anal. Chem.

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ABSTRACT*The thermoelectric vapor pressure osmometer is established as a satisfactory instrument for the determination of the vapor pressure lowering of solutes in solutions. The calibration constant, a 1 , of the instrument is demonstrated to be independent of the nature of the solute and can be calculated from a knowledge of the system geometry and measurable thermodynamic and transport parameters.Experimental results are evaluated in terms of the change in resistance of the thermistor and the concentration of solution. It is necessary to use a seconddegree equation in concentration plot to fit the data. Evaluation of the coefficient of the second-order term requires the incorporation of a heat-of-mixing term in the form of the Van Laar equation. The concentrationindependent term 8 for the heat of mixing is obtained for fourteen solute-solvent pairs.

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The steady‐state temperature difference in the Hill‐Baldes technique

Iyengar

1954

Recl. Trav. Chim. Pays‐Bas

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The molal steady-state temperature differences 6 for a number of solvents have been determined by the Hill-Baldes technique, using a precision themistof bridge. The values of d obtained in the present investigation as well as those available in the literature have been explained on the basis of the theory of evaporation of droplets after introducing a thermal efficiency factor, which is characteristic of the experimental method employed. The application of this technique for the determination of molecular weights in solution is also discussed.Baldes' technique of measuring the steady-state temperature difference, set up between a drop of solvent and a drop of a solution suspended in a chamber saturated with the vapour of the solvent, was first applied by Tay2or and Ha22 1) for the determination of molecular weights of substances in organic solvents. They observed that organic solvents, as compared with water, had a higher proportionality constant between the steady-state temperature difference and the effective molal concentration of solute. Neither these authors nor the subsequent investigators *) 3 ) could account quantitatively for the proportionality constants 8 in terms of the properties of the solvents. Recently4) an empirical relationship was proposed between the observed values of 6 and those evaluated from thermodynamics and the psychometric theory. In the present investigation 8 has been determined for various solvents by means of a thermistor bridge, which was previously used 3) 5 ) 6 ) for the determination of osmotic coefficients and molecular weights in solution. Many refinements have now been effected in this 1) G. B. Taylor and M. B. Hall, Anal. Chem. 23, 947 (1951).

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Measurement of Molecular Weight in Organic Solvents

Cited by 15 publications

References 12 publications

A Thermometric Method for Thermodynamics Studies and Molecular Weight Determinations in Solutions

A Thermometric Method for Thermodynamics Studies and Molecular Weight Determinations in Solutions

Thermoelectric vapor-pressure osmometry

The steady‐state temperature difference in the Hill‐Baldes technique

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