Entropic cost of restricting a rotor within a hydrocarbon chain

Range -1.6 to -3.6 kJ/mol
Organism Generic
Reference Mark S. Searle , Dudley H. Williams, The cost of conformational order: entropy changes in molecular associations. J. Am. Chem. Soc., 1992, 114 (27), pp 10690–10697 DOI: 10.1021/ja00053a002 abstract
Comments "Molecules in solution have degrees of freedom of overall translation and rotation, as well as internal rotations about single bonds, that become highly constrained when two molecules associate to form a stable complex. [Investigators] have considered the thermodynamics of fusion and sublimation of hydrocarbons and polar organic molecules as instructive models for features of complex dissociation. The entropy of fusion within homologous series of alkanes, alkyl carboxylic acids, and 2-methyl ketones provides an estimate of the entropic cost of restricting a rotor, within a hydrocarbon chain, as -1.6 to -3.6 kJ/mol (T?S at 300 K) upon crystallization."
Entered by Uri M
ID 111418