2,3-dimethyl-2-butene: thermodynamic properties in the solid, liquid, and vapor states

Journal Article · Wed Oct 05 00:00:00 EDT 1955 · J. Am. Chem. Soc.; (United States)

DOI:https://doi.org/10.1021/ja01624a013· OSTI ID:7305373

Scott, D W; Finke, H L; McCullough, J P; Gross, M E; Messerly, J F; Pennington, R E; Waddington, G

Various thermodynamic properties of 2,3-dimethyl-2-butene were studied experimentally. The entropy of the liquid a 298.16/sup 0/K (S/sub satd/ = 64.58 cal deg /sup 1/ mole/sup -1/) was computed from calorimetric values of the heat capacity in the solid and liquid states (11 to 318/sup 0/K) and of the heats of transition and fusion (844 cal mole/sup -1/ at 196.82/sup 0/K and 1542 cal mole/sup -1/ at the triple point, 198.92/sup 0/K, respectively). Results obtained for the heat capacity of the liquid (C/sub satd/), vapor pressure (p), heat of vaporization (..delta..H/sub v/), heat capacity in the ideal gas state (C/sup 0//sub p/), and the second virial coefficient (B = (PV - RT)/P) are represented as a function of temperature by the following empirical equations: (1) C/sub satd/ = 48.178 - 0.16068T + 6.2188 x 10/sup -4/T/sup 2/ - 5.2083 x 10/sup -7/T/sup 2/, cal deg/sup -1/ mole/sup -1/) (200 to 320/sup 0/K); (2) log/sub 10/p (mm) = 6.93324 - 1206.037/(t + 224.400), (29 to 73/sup 0/); (3) ..delta..H/sub v/ = 10,674 - 5.713T - 0.01344T/sup 2/, cal mole/sup -1/ (292 to 346/sup 0/K); (4) C/sup 0//sub ..nu.. = 4.454 + 0.087361T - 1.1983 x 10/sup -4/T/sup 2/, cal deg/sup -1/ mole/sup -1/ (334 to 473/sup 0/K); and B = -2764 - 4.93 exp (1100/T), cc mole/sup -1/ (292 to 473/sup 0/K). The entropy in the ideal gas state at 298.16/sup 0/K (S/sup 0/ = 87.16 cal deg/sup -1/ mole/sup -1/) was computed from these data. A vibrational assignment was made for 2,3-dimethyl-2-butene, and the average height of the potential barriers hindering internal rotation of the methyl groups, 680 cal mole/sup -1/, was evaluated from the calorimetric data. Values of the functions (F/sup 0/ - H/sub 0//sup 0/)/T, (H/sup 0/ - H/sub 0//sup 0/)/T, H/sup 0/ - H/sub 0//sup 0/, S/sup 0/ and C/sup 0//sub p/ were calculated at selected temperatures to 1500/sup 0/K.

• Research Organization: Bureau of Mines, Bartlesville, OK
• OSTI ID: 7305373
• Journal Information: J. Am. Chem. Soc.; (United States), Vol. 77:19
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
HEXENES
ENTROPY
FUSION HEAT
SPECIFIC HEAT
TRANSITION HEAT
VAPORIZATION HEAT
HIGH TEMPERATURE
ISOMERS
LIQUIDS
LOW TEMPERATURE
MEDIUM TEMPERATURE
SOLIDS
TEMPERATURE DEPENDENCE
ULTRALOW TEMPERATURE
VAPORS
VERY HIGH TEMPERATURE
VERY LOW TEMPERATURE
ALKENES
ENTHALPY
FLUIDS
GASES
HYDROCARBONS
ORGANIC COMPOUNDS
PHYSICAL PROPERTIES
THERMODYNAMIC PROPERTIES
400301* - Organic Chemistry- Chemical & Physicochemical Properties- (-1987)