Temperature dependence of the Kovats retention indices for alkyl 1, 3-diketones on a DB-5 capillary column

Abstract

A series of alkyl 1,3-diketones were used to study the temperature dependence of the Kovats retention indices in the temperature range 130–190 ºC (403–463 K). The temperature dependence is described by the empirical equation I = B B/T + ClnT. On the basis of this equation, the activation enthalpy, ΔH≠, and the chemical potential of the partitioning of one methylene group between the two phases of the chromatographic system, Δμp(CH2), were calculated. Also the Kovats retention indices – boiling point correlations (linear and reciprocal) for alkyl 1,3-diketones were studied and Δμp(CH2) was calculated.

U radu su dati Kovačevi retencioni indeksi 1,3-diketona dobijeni na kapilarnoj koloni DB-5 u temperaturnom intervalu 130–190 ºC. Dobijeni retencioni indeksi analizirani su korišćenjem izraza I =A+B/T +ClnT. Na osnovu dobijenih vrednosti konstanti B i C izračunata je vrednost entalpije aktivacije, ΔH≠, kao i particioni hemijski potencijal, Δμp(CH2). Takođe je razmatrana zavisnost Kovačevog retencionog indeksa od temperature ključanja 1,3-diketona upotrebom linearnog i reciprocionih modela. Iz dobijenih vrednosti konstanti datih modela izračunat je particioni hemijski potencijal Δμp(CH2).