The reactivity of α,β-unsaturated carboxylic acids. Part XVI. The kinetics of the reaction of cycloalkenecarboxylic and cycloalkenylacetic acids with diazodiphenylmethane in various alcohols

• Published in: Journal of the Serbian Chemical Society Vol. 67; no. 2; pp. 77 - 85
• Main Authors: Uscumlic, Gordana, Nikolic, Jasmina, Krstic, Vera
• Format: Journal Article
• Language: English
• Published: Serbian Chemical Society 2002
• Subjects: cycloalkenecarboxylic acids; cycloalkenylacetic acids; diazodiphenyl-methane; kinetic measurements; protic solvents
• ISSN: 0352-5139; 1820-7421
• DOI: 10.2298/JSC0202077U

The rate constants for the reaction of diazodiphenylmethane with 1-cyclopentenecarboxylic, 1-cycloheptenecarboxylic, cyclopent-1-enylacetic and cyclohept-1-enylacetic acids were determined in eight alcohols at 30 ?C using the appropriate UV-spectroscopic method. In order to explain the kinetic results through solvent effects, the second order rate constants of the examined acids were correlated using a total solvatochromic equation, of the form: log k = A0+ s?*+a??+ b?, where ?* is a measure of the solvent polarity, ??represents the scale of solvent hydrogen bond acceptor basicities and ? represents the scale of solvent hydrogen bond donor acidities. The correlations of the kinetic data were carried out by means of multiple linear regression analysis. The opposite sings of the electrophilic and the nucleophilic parameters are in agreement with the well-known reaction mechanism. The results presented in this paper were compared with the kinetic data for 1-cyclohexenecarboxylic and cyclohex-1-enylacetic acids obtained under the same experimental conditions. Konstante brzina za reakciju izmedju diazodifenilmetana (DDM) i 1-ciklopentenkarbonske, 1-cikloheptenkarbonske, ciklopent-1-enilsircetne i ciklohept-1-enilsircetne kiseline su odredjene u osam alkoholnih rastvaraca na 30 ?C odgovarajucim UV-spektrofotometrijskim metodom. Da bi se dobijeni kineticki rezultati objasnili kroz efekte rastvaraca konstante brizna reakcije (k) su korelisane totalnom solvatohromnom jednacinom oblika: log k = A0+ s?*+a??+ b?, gde je ?* mera polarnosti rastvaraca, ??predstavlja skalu baznosti rastvaraca kao akceptora protona u vodonicnoj vezi, a ??skalu kiselosti rastvaraca kao donora protona u vodonicnoj vezi. Korelacija kinetickih parametara je izvrsena metodom visestruke linearne regresione analize. Suprotni znaci uz elektrofilni i nukleofilni parametear u saglasnosti su sa izvedenim mehanizmom reakcije. Rezultati prikazani u ovom radu su uporedjeni sa kinetickim podacima za 1-cikloheksenkarbonsku i cikloheks-1-enilsircetnu kiselinu, dobijenim pod istim eksperimentalnim uslovima.