Effect of Pressure on the Solvolysis of Dimethyl-t-butyl Sulfonium Iodide in Ethanol–Water Mixtures

1972 ◽  
Vol 50 (14) ◽  
pp. 2270-2275 ◽  
Author(s):  
Claude S. Davis ◽  
J. B. Hyne

The pressure dependence of the rate of solvolysis of dimethyl-t-butyl sulfonium iodide has been studied in ethanol–water mixtures at 60.00 °C. Determination of the partial molal volume of the substrate ions has enabled the volumes of activation to be dissected into initial and transition state components. The solvent composition dependence of the partial molal volumes of the two states provides further details of the nature of the reaction mechanism.

1970 ◽  
Vol 48 (15) ◽  
pp. 2416-2422 ◽  
Author(s):  
Digby D. Macdonald ◽  
J. B. Hyne

The partial molal volumes of a series of tetraalkylammonium chlorides in aqueous acetone and aqueous dimethylsulfoxide at 25.000 °C are reported as a function of solvent composition. It is shown that for each solvent composition the partial molal volume data are better represented by a quadratic in solute molecular weight than by the linear expression previously employed in similar studies. Extrapolation of molecular partial molal volumes to zero cation molecular weight has permitted evaluation of the partial molal volumes of the ions R4N+ and Cl−. The variation of molecular and ionic partial molal volume as a function of solvent composition is discussed.


1980 ◽  
Vol 58 (17) ◽  
pp. 1795-1798 ◽  
Author(s):  
Y. K. Sze ◽  
W. A. E. McBryde

Partial molal volumes have been determined for the nickel(II) complexes of ethylenediaminetetraacetic acid (mono complex) and methyliminodiacetic acid (bis complex). The formation of these is accompanied by appreciable increases in volume, greater in the case of the second ligand. The observations are discussed in terms of reduced electrostriction of water by the complexes, and the different volume increases are accounted for by structural features of the complexes which are partially confirmed by spectral measurements.


1969 ◽  
Vol 47 (8) ◽  
pp. 1437-1439 ◽  
Author(s):  
Ikchoon Lee ◽  
J. B. Hyne

The solvent composition dependence of the partial molal volume of the transition state of benzyl chloride solvolysing in water–ethanol mixtures is compared with that of anilinium chloride and a number of quaternary alkyl ammonium chlorides. It is concluded that anilinium chloride is not a good electrostatic model for the benzyl chloride transition state even though it may be a fair structural model. The partial molal volume of tetraethylammonium chloride is very similar to that of the transition state suggesting that charge development in the activation process is far from being fully ionic.


1986 ◽  
Vol 64 (2) ◽  
pp. 387-393 ◽  
Author(s):  
Ester F. G. Barbosa ◽  
Isabel M. S. Lampreia

Apparent molal volumes, [Formula: see text], of secondary and tertiary amines and linear hydrocarbons were determined in benzene at 25 °C, using a vibrating tube densimeter. These quantities have been extrapolated to infinite dilution to obtain partial molal volumes. The contribution to partial molal volume of the amine groups, calculated using a simple additive scheme, [Formula: see text], were interpreted in terms of conformational effects present in these molecules. A first attempt to find a measure of the contribution to the partial molal volume of the specific interaction amine–benzene in tertiary and secondary amines was made. The results agree well in the two different approaches used.


1970 ◽  
Vol 48 (13) ◽  
pp. 2025-2030 ◽  
Author(s):  
MOYRA J. Mackinnon ◽  
A. B. Lateef ◽  
J. B. Hyne

The transition state partial molal volume behavior, [Formula: see text] as a function of binary solvent composition was obtained for three reactions by dissection of the activation volume, ΔV*, into initial and transition state components: [Formula: see text] The solvolyses of t-butyl chloride, benzyl chloride, and p-chlorobenzyl chloride represented a gradation of reaction type between SN1 and SN2 and the transition state partial molal volume behavior was found to be distinctly different in each case and in agreement with the mechanistic classification of these reactions.


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