Vapor pressure isotope effects in the benzene (B) --cyclohexane (C) system from 5 to 80 /sup 0/C. I. The pure liquids B-d/sub 0/,B-d/sub 1/,ortho-,meta-, and para-B-d/sub 2/, B-d/sub 6/,C-d/sub 0/, and C-d/sub 12/. II. Excess free energies and isotope effects on excess free energies in the solutions B-h/sub 6//B-d/sub 6/, C-h/sub 12//C-d/sub 12/, B-h/sub 6//C-h/sub 12/, B-d/sub 6//C-h/sub 12/, and B-h/sub 6//C-d/sub 12/
High precision measurements of the vapor pressure differences between some deuterated benzenes B-d/sub x/ (x=1, para-2, and 6) and protio benzene B-d/sub 0/; between para- and ortho-, and para- and meta-dideuterobenzene; and between perdeuterocyclohexane C-d/sub 12/ and protiocyclohexane C-d/sub 0/ were made from near the freezing point to the normal boiling point. The data are best represented as the logarithmic ratios ln R (d/sub 6/) =ln (P/sub d/0/P/sub d/6) =1226.5/T/sup 2/-12.178/T, ln R (para/ortho) =ln (P/sub parahyphend/2/P/sub orthohyphend/2) =2.6/T/sup 2/, and ln R (para/meta) =ln (P/sub parahyphend/2/P/sub metahyphend/2) =-2.0/T/sup 2/, together with the deviations from the law of the mean ..delta.. (d1) =6-(ln R (d/sub 6/)/lnR (d/sub 1/))=0.177-3.6 x 10/sup -4/t and ..delta.. (d/sub 2hyphenpara/=3-(ln R (d/sub 6/)/ln R (d/sub 2hyphenpara/))=0.028 +1.0 x 10/sup -4/t. The isotope effects are inverse and display significant deviations from the law of the mean. The cyclohexane results are given by ln R (C-d/sub 12/) =-2188.4/T/sup 2/-18.587/T. New measurements of the vapor pressures of benzene--cyclohexane solutions are also reported between 5 and 80 /sup 0/C. The data are in good agreement with the best earlier work. Excess free energies of the equimolar solutions B-h/sub 6//B-d/sub 6/ and C-h/sub 12//C-d/sub 12/ have been measured between 20 and 80 /sup 0/C. Suitable fits to the data yield the following results (30 /sup 0/C); G/sup ex/(B-h/B-d), G/sup ex/(C-h/C-d); H/sup ex/(B-h/B-d),
- Research Organization:
- Chemistry Department, University of Tennessee, Knoxville, Tennessee 37916
- OSTI ID:
- 5120323
- Journal Information:
- J. Chem. Phys.; (United States), Vol. 68:7
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
BENZENE
VAPOR PRESSURE
CYCLOHEXANE
DEUTERIUM
ISOTOPE EFFECTS
DEUTERIUM COMPOUNDS
SOLUTIONS
ALKANES
AROMATICS
CYCLOALKANES
DISPERSIONS
HYDROCARBONS
HYDROGEN COMPOUNDS
HYDROGEN ISOTOPES
ISOTOPES
LIGHT NUCLEI
MIXTURES
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
PHYSICAL PROPERTIES
STABLE ISOTOPES
THERMODYNAMIC PROPERTIES
400302* - Organic Chemistry- Isotope Effects- (-1987)