What about functionalized hydrocarbons. Do values of lgHm(298 What about functionalized hydrocarbons? Do values of lgHm(298.15 K) correlate with slngHm(Tm)? Hv(298)/kJmol-1=4.69(nC -nQ)+1.3nQ+3.0+nMM +b +C For the present let’s ignore metals and lump the quaternary carbons contribution with the constant. Hv(298)/kJmol-1  4.69nC + b + C if we allow C to be a variable, then this relationship is an equality such that 4.69nC + b >> C

The b term can be expressed as 4.69*a such that b = 4.69*a Then Hv(298)/kJmol-1  4.69(nC + a) + C Hv(298)/kJmol-1  4.69nC’ + C where nC’ = (nC + a) Since 298.15 is an arbitrary temperature, the following relationship should hold for any temperature. Hv(Tm)/kJmol-1  AnC’ + B + C’ It should be possible to express B (contribution of the functional group as B = 4.69*a + c as long as we are referring to the same functional group Hv(Tm)/kJmol-1 = A(nC + a) + C’’ if we allow C’’ to be a variable

Hv(Tm)/kJmol-1 = A(nC + a) + C’’ Hv(Tm)/kJmol-1 = AnC’ + C’’ slnHm(Tm)/kJmol-1 is generally small and its contribution can be expressed in similar form. slnHm(Tm) = A’nC’ + C’’’ where C’’’ is a variable. slope = lgHm (298.15 K) / slngHm(Tm) slope = (4.69nC’ + C)/(AnC’ + C’’+ A’nC’ + C’’’ ) slope = (4.69nC’ + C’)/[(A+A’) nC’ +C’’+C’’’] slope = [MnC’ + X]/[M’nC’ + X’]

Consequences of this analysis: 1. Only compounds with the same functional group can be correlated. 2. Only compounds with the same number of functional groups can be correlated unless: a) group values of the functional group are the same as for C; b) the number of carbon atoms is kept constant and the number of identical functional groups varied.

Ethers tertiary amines and hydrocarbons correlate. "The vaporization enthalpies of some crown ethers by correlation gas-chromatography", Nichols, G. Orf, J.; Reiter, S.; Chickos, J. S.; Gokel, G. W. Thermochimica Acta 2000, 346, 15-28. "A thermochemical and theoretical study of the phenylpyridine isomers," Ribeiro da Silva, M. A. V.; Matos, M. A. R.; Rio, C. A.; Morais, V. M. F.; Wang, J.; Nichols G.; Chickos, J. S. J. Phys. Chem. 2000, 104, 1774-1778. ketones and esters correlate “The Enthalpies of Formation of Two Dibenzocyclooctadienones,” St. Perisanu, St. Contineanu, J.; Banciu, M. D.; Liebman, J. F.; Farivar, B. S.; . Mullan, M. A.; Chickos, J. S.; Rath, N.; Hillesheim, D. M. Thermochim. Acta 2003, 400, 109-120.