A kinetic and mechanistic study on synthesis reaction of 2-(4bromophenyl)-2,3-dihydroquinazolin-4(1H)- ones

For the first time, kinetic studies were made of the two-component reaction between 4-bromobenzaldehyde 1 and 2-aminobenzamid 2 in the presence of formic acid as a solvent and catalyst. To ascertain the kinetic of the reaction, monitoring was conducted using UV spectrophotometry technique. The overall order of reaction was automatically obtained by the second order fitting. The reaction was successively at different temperature ranges, the relationship of the second order rate constant (Lnk2) and (LnK2/T) on the reverse temperature were good consent with Arrhenius and Eyring equations. This collected the suitable schemes to calculate the kinetic and activation parameters (Ea, ΔH‡, ΔS‡ and ΔG‡) of the reaction. Furthermore, useful information was obtained from considering of the effect of solvent and change of concentration of catalyst on the reaction rates. The proposed mechanism was confirmed correctness to the obtained results. The conclusions showed that the first step of the mechanism is a rate determining step (RDS).

Keywords:

kinetics , catalyst , mechanism , quinazoline derivatives