Relation between van der Waals and Partial Molal Volumes of Organic Molecules in Water

The partial molal volumes [Formula: see text] of nonpolar organic molecules (i.e. those having more than three aliphatic carbon atoms per polar hydroxyl, ether, amine, amide, or urea group) in water at 25 °C are given by their van der Waals volumes υw plus the additional empty volume provided by an enclosing shell 0.53 Å thick. An equation relates [Formula: see text] to υw More polar compounds (i.e. those having fewer than two or three aliphatic carbon atoms per polar group) have [Formula: see text] smaller than calculated by the equation; the shrinkage in [Formula: see text] from that computed is linearly related to the fraction of the total surface area of the molecule occupied by the polar group.

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Partial molal volumes of some halobenzenes in carbon tetrachloride

Canadian Journal of Chemistry ◽

10.1139/v83-247 ◽

1983 ◽

Vol 61 (7) ◽

pp. 1414-1416 ◽

Cited By ~ 6

Author(s):

Fereidoon Shahidi

Keyword(s):

Carbon Tetrachloride ◽

Infinite Dilution ◽

Van Der Waals ◽

Alkyl Halides ◽

Substituted Benzenes ◽

Halogen Atoms ◽

Partial Molal Volumes ◽

Molal Volumes

The partial molal volumes at infinite dilution [Formula: see text] for a number of halobenzenes are measured and related to their van der Waals volumes. Results indicate larger volume increments for halogen atoms in halobenzenes than those in alkyl halides. Possible explanations are forwarded. The effect of steric overcrowding in ortho-substituted benzenes on the [Formula: see text] values are evaluated.

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Deuterium isotope effects on the partial molal volumes of cyclohexane, acetone, and acetonitrile in carbon tetrachloride

Canadian Journal of Chemistry ◽

10.1139/v83-460 ◽

1983 ◽

Vol 61 (12) ◽

pp. 2684-2687 ◽

Cited By ~ 5

Author(s):

G. Ronald Brown ◽

Julian K. Edward ◽

John T. Edward

Keyword(s):

Carbon Tetrachloride ◽

Steric Effect ◽

Isotope Effects ◽

Polar Compounds ◽

Molar Volumes ◽

Partial Molal Volumes ◽

Deuterium Isotope Effects ◽

Molal Volumes

At 25 °C both molar volumes V and partial molal volumes [Formula: see text] in carbon tetrachloride of cyclohexane-d12 and of acetone-d6 are smaller than V and [Formula: see text] of the corresponding protio compounds. However, both V and [Formula: see text] of acetonitrile-d3 are larger than V and [Formula: see text] of acetonitrile-h3, and in solvent cyclohexane [Formula: see text] of acetone-d6 and of acetone-h6 are approximately equal. Apparently deuteration has not only a steric effect, but (in polar compounds) a counter-balancing effect, which may be polar.

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Partial molal volumes of organic compounds in carbon tetrachloride. IV. Ketones, alcohols, and ethers

Canadian Journal of Chemistry ◽

10.1139/v79-418 ◽

1979 ◽

Vol 57 (19) ◽

pp. 2585-2592 ◽

Cited By ~ 22

Author(s):

John T. Edward ◽

Patrick G. Farrell ◽

Fereidoon Shahidi

Keyword(s):

Carbon Tetrachloride ◽

Organic Compounds ◽

Linear Relation ◽

Reasonable Agreement ◽

Van Der Waals ◽

Partial Molal Volumes ◽

Molal Volumes

The partial molal volumes [Formula: see text] in carbon tetrachloride at 25 °C of 13 ketones, 18 alcohols, and 17 mono- or poly-functional ethers, all acyclic, have been determined. Results are in reasonable agreement with [Formula: see text] calculated from an equation developed previously, using previous parameters plus the following: increments (in mL mol−1) of 8.72 for carbonyl, 6.1 for hydroxyl, 4.4 for oxygen in a monofunctional ether, and 5.8 for oxygen in a polyfunctional ether; decrements δ (in mL mol−1) of −1.68 for [Formula: see text] for [Formula: see text] for [Formula: see text] for [Formula: see text], and −1.93 for [Formula: see text]. The increments for carbonyl and hydroxyl are smaller than the van der Waals volumes of these groups, and indicate some degree of complexation to carbon tetrachloride. Only a roughly linear relation is found between [Formula: see text] of alcohols in water and [Formula: see text] in carbon tetrachloride, possibly because of the intrusion of additional effects such as structure-promotion in water.

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