J. Mccullough, D. R. Douslin, W. Hubbard
Nov 1, 1959
Citations
0
Influential Citations
26
Citations
Journal
Journal of the American Chemical Society
Abstract
The chemical thermodynamic properties of pyrrolidine in the ideal gaseous state (0 to 1500/sup 0/K) were calculated by use of calorimetric, spectroscopic and molecular structure information. In common with other saturated molecules with five-membered rings, the pyrrolidine molecule has a ''pseudorotational'' degree of freedom. Best agreement between calculated and observed thermodynamic properties was obtained by assuming pseudorotation to be hindered by a potential barrier of 300 cal. mole/sup -1/. Experimental studies provided the following information: values of heat capacity for the solid above 13/sup 0/K; the liquid below 350/sup 0/K and the vapor between 350 and 500/sup 0/K; temperature of a first-order transition in the solid state, triple point temperature; heats of transition, fusion and vaporization; thermodynamic functions for the solid and liquid (0 to 360/sup 0/K); vapor pressure (43 to 121/sup 0/); equation of state parameters; and standard heats of combustion and formation at 298.16/sup 0/K. An unusual anomaly, possibly related to the effects of restricted pseudorotation and/or association, was observed in the heat capacity of liquid pyrrolidine.