A linear solvation energy relationship study for the reactivity of 2-substituted cyclohex-1-enecarboxylic and 2-substituted benzoic acids with diazodiphenylmethane in aprotic and protic solvents

Abstract

The rate constants for the reaction of 2-substituted cyclohex-1-enecarboxylic acids and the corresponding 2-substituted benzoic acids with diazodiphenylmethane were determined in various aprotic solvents at 30 ºC. In order to explain the kinetic results through solvent effects, the second order rate constants of the reaction of the examined acids were correlated using the Kamlet-Taft solvatochromic equation. The correlations of the kinetic data were carried out by means of multiple linear regression analysis and the solvent effects on the reaction rates were analyzed in terms of the contributions of the initial and transition state. The signs of the equation coefficients support the proposed reaction mechanism. The quantitative relationship between the molecular structure and the chemical reactivity is discussed, as well as the effect of geometry on the reactivity of the examined molecules.

Konstante brzine za reakciju 2-supstituisanih cikloheks-1-enkarboksilnih i odgovarajućih 2-supstituisanih benzoevih kiselina sa diazodifenilmetanom su određene u nizu različitih aprotičnih rastvarača na temperaturi od 30 °S. Da bi se kinetički rezultati objasnili pomoću efekata rastvarača, dobijene konstante brzine reakcije drugog reda su korelisane Kamlet-Taftovom solvatohromnom jednačinom. Korelacije kinetičkih podataka su dobijene pomoću metode višestruke linearne regresione analize i efekti rastvarača su posebno analizirani u odnosu na osnovno i prelazno stanje. Aritmetički znaci ispred koeficijenata solvatohromnih parametara rastvarača odgovaraju pretpostavljenom mehanizmu ispitivane reakcije. Takođe je proučavan kvantitativni odnos molekulske strukture i reaktivnosti, kao i efekat geometrije molekula ispitivanih jedinjenja na njihovu reaktivnost.