Detail of "16747-26-5"

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Interactions in alkane systems by depolarized Rayleigh scattering and calorimetry

Interactions in alkane systems by depolarized Rayleigh scattering and calorimetry. Part 1. Orientational order and condensation effects in n-hexadecane + hexane and nonane isomers. Tancrede, Pierre; Bothorel, Pierre; de St. Romain, Pierre; Patterson, Donald (CNRS, Domaine Univ., Talence, Fr.). J. Chem. Soc., Faraday Trans. 2, 73(1), 15-28 (English) 1977. CODEN: JCFTBS. DOCUMENT TYPE: Journal CA Section: 22 (Physical Organic Chemistry) Section cross-reference(s): 69 Mol. optical anisotropies, .gamma.2, were obtained from depolarized Rayleigh scattering expts. on the 5 hexane isomers and 15 nonane isomers with varying degrees of branching. Values of .gamma.2 at high diln. in CCl4 reflect the anisotropies of the isomer shapes. Values of .gamma.2 for the pure compds.Several reagents with their cas registry numbers 922-28-1 and 16747-26-5 are used here. contain a contribution due to correlation of the orientations of neighboring mols. For highly branched, isotropic isomers in the pure state and in dil. soln., the .gamma.2 values are the same and are small. The pure state .gamma.2 value increases faster than does the dil. soln. value, the divergence reflecting the increased correlation of mol. orientations. Values of .gamma.2 for dil. n-C16H34 solns. in the hexanes and nonanes increase with the anisotropy of the solvent mols. and yield values of the J12 parameter; which characterizes the correlation of orientations of n-C16H34 and the solvent mols. The J12 values indicate that orientational order is destroyed on mixing and thus explains the heat of mixing data for n-C16H34 + hexane systems. The molar heats of mixing (.DELTA.hm) at 25.degree. for n-C16H34 with 21 nonane isomers increase with nonane branching and with .DELTA.J12. For nonane isomers with high degrees of steric hindrance a large neg. contribution to .DELTA.hm is obsd. The effect resembles a condensation of the less hindered alkane into the larger, more hindered alkane. .