The densities of the title compounds and of their solutions (0,25,50,75, and 100 nominal mol %) have been measured between 0.1 and 35 MPa at 15, 25, and 40 OC. The data are reported in terms of the parameters of fit to the Tait equation, and as volumes, compressibilities, K, and reduced compressibilities, KR (KR-I = V/(KRT)), and as excess volumes, excess compressibilities, and excess reduced compressibilities for the solutions. The melting points of C6H12 and C6D12 are reported from 0.1 to 25 MPa. Isotope effects on the volumetric properties of benzene and cyclohexane are small002 and -0.013 & 0.002, respectively), and excess compressibilities for solutions of isotopic isomers, one in the other, are zero within the experimental precision. The data are interpreted in terms of the statistical theory of condensed-phase isotope effects and by using a model which partitions the compressibilities into hard-sphere (HS), librational, internal, and intermolecular attractive parts. Using the model, we calculated the compressibilities, the isotope effects on compressibility, and the excess compressibility of the solutions all in a self-consistent fashion and in agreement with experiment.The sharp heat capacity anomaly in pure sulfur at the polymerization transition is rounded by dopants such as I,, Br,, and C1, far more than can be accounted for by the presence of an inert diluent. We extend the nonclassical scaling theory of the polymerization transition in liquid sulfur based on the n = 0 limit of the n vector model of magnetism to the polymerization of sulfur in the presence of a reactive dopant. A comparison is made among a mean-field theory of doped sulfur, the nonclassical theory, and the experimental data of Feher et al. With use of the parametric equation of state for the n -+ 0 vector model recently employed to describe polymerization of "living" polymers, an improved description of the properties of pure sulfur is obtained.

The coefficients of thermal expansion of tetradecane, hexadecane, octadecane, and tetracosane have been measured continuously for considerable temperature ranges on both sides of the melting points. The increase of these coefficients in the neighborhood of the melting points is suggestive of an order-disorder mechanism for the transitions. Although the effect is observed to be larger on the solid side of the transition than on the liquid, the latter is interpreted as more significant, since the presence of impurities and the open, mosaic structure of the solid contribute largely to the increase. Likely impurities are not of the Raoult type, and do not cause appreciable variations.

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The third run was made under the same conditions using 1% concentrated sulfuric acid as catalyst. The temperature ranged from 135-132°C. during the 3-hour run, and the final percentage of esterification was 92.9. The three final products were very light in color. In all cases there was an initial drop in temperature after the acid and alcohol had reacted.

MUCHwork has been reported on the rates of crystallization of sucrose from pure and impure solutions. Sugar refining processes operate under the latter, condition, and the time factor in such a case is vastly different from that under ideal conditions of high purity.