The study of linear solvation energy relationship for the reactivity of carboxylic acids with diazodiphenylmethane in protic and aprotic solvents

Solvent effects on the reactivity of cycloalkenecarboxylic, cycloalkeneacetic, 2-substituted cyclohex-1-enecarboxylic, 2-substituted benzoic, 2-substituted cyclohex-1-eneacetic, 2-substituted phenylacetic, 2-phenylcyclohex-1-enecarboxylic, 2-phenylbenzoic and 2-phenylacrylic acids with diazodiphenylmethane (DDM) were investigated. In order to explain the kinetic results through solvent effects, the second-order rate constants for the reaction of the examined acids with DDM were correlated using the Kamlet-Taft solvatochromic equation. The correlations of the kinetic data were realized 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 the transition state. The signs of the equation coefficients support the proposed mechanism. Solvation models for all the investigated acids are suggested. The quantitative relationship between the molecular structure and the chemical reactivity is also discussed. Uticaj rastvaraca na reaktivnost cikloalkenkarbonskih, cikloalkensircetnih, 2-supstituisanih cikloheks-1-enkarbonskih, 2-supstituisanih cikloheks-1-ensircetnih, 2-supstituisanih benzoevih, 2-supstituisanih fenilsircetnih, 2-fenilcikloheks-1-enkarbonske, 2-fenilbenzoeve i 2-fenilakrilne kiseline sa diazodifenilmetanom je proucavan u nizu proticnih i aproticnih rastvaraca. Da bi se kineticki rezultati objasnili pomocu efekata rastvaraca, dobijene konstante brzine reakcije drugog reda su korelisane pomocu Kamlet-Taftove solvatohromne jednacine. Korelacije kinetickih podataka su izvrsene pomocu metode visestruke linearne regresione analize, a efekti rastvaraca su posebno analizirani u odnosu na osnovno i prelazno stanje. Aritmeticki znaci ispred koeficijenata solvatohromnih parametara odgovaraju pretpostavljenom mehanizmu ispitivane reakcije. Predlozen je solvatacioni model za sve proucavane kiseline, koji je pokazao da postoji kvantitativni odnos molekulske strukture i njihove reaktivnosti.