Pressure dependence of the structure and properties of liquid n-butane

Journal Article · Wed Aug 12 04:00:00 EDT 1981 · J. Am. Chem. Soc.; (United States)

DOI:https://doi.org/10.1021/ja00406a010· OSTI ID:6360332

Jorgensen, W L

The effects of pressure on the structure, thermodynamic properties, and conformational equilibrium for liquid n-butane have been studied via statistical mechanics simulations at 1, 5000, and 15,000 atm. Consistent with Raman experiments on lower n-alkanes, increased pressure is found to increase the gauche populations in liquid n-butane; however, the shift amounts to only a 7% change in the population in going from 1 to 15,000 atm at -0.5/sup 0/C. Various computed properties are found to be in very good agreement with experimental values including the density, heat of vaporization, and compressibility for which the discrepancies are 3, 4, and 10%, respectively, at 1 atm. The sharpening of the radial distribution functions reflects increased structure at higher pressure, though the effects are not striking in stereoplots even at 15,000 atm. Interestingly, the energy of liquid n-butane is computed to be lowest at 5000 atm which is in accord with Bridgman's observations in 1913 for a variety of organic liquids. Overall, a key finding is that the simple Lennard-Jones description of the intermolecular interactions remains successful over the pressure range studied which represents a compression of 33%. 9 figures.

• Research Organization: Purdue Univ., West Lafayette, IN
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 6360332
• Journal Information: J. Am. Chem. Soc.; (United States), Journal Name: J. Am. Chem. Soc.; (United States) Vol. 103:16; ISSN JACSA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400301* -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987)
ALKANES
BUTANE
CHEMICAL REACTIONS
COMPRESSIBILITY
DENSITY
DIMERIZATION
ENTHALPY
FLUIDS
HYDROCARBONS
LIQUIDS
MECHANICAL PROPERTIES
MONTE CARLO METHOD
ORGANIC COMPOUNDS
PHYSICAL PROPERTIES
POLYMERIZATION
PRESSURE DEPENDENCE
SIMULATION
THERMODYNAMIC PROPERTIES
TRANSITION HEAT
VAPORIZATION HEAT
VERY HIGH PRESSURE