Abstract

This study involved akinetic analysis using a spectrophotometric method by monitoring the formation of an orange azo dye resulting from the reaction of the diazotized metoclopramide reagent ((Z)-5-chloro-4-(chlorodiazenyl)-N-(2-(diethylamino)ethyl)-2-methoxybenzamide) with resorcinol. The reaction was condected at 294 K and a wavelength of λmax=300nm (characteristic of the resulting dye ) in an acidic medium (pH=4.41) under conditions optimized spectrophotometrically. A 1:1 mole ratio of reactants (resorcinol: diazotized metoclopramide reagent) was used, with an aqueous solution concentration of 0.5x 10-3 mol.L-1 for each. Dye formation kinetics were investigated by monitoring formation times using the aforementioned instrument. It was observed that increasing the reagent concetration tenfold (to 5.0 x 10-3 mol.L-1) did not affect the rate constant (k1) of the dye formation reaction show that the reaction follows pseudo-first-order kinetics with respect to resorcinol. This enabled the calculation of the dye formation rate-constant at four temperatures (274, 284. 294 and 304K), with the highest value recorded at 304 K (0.0705 min-1 ) and the lowest at 274 K (0.0599min-1). In addition to calculating the half-lives for the dye formation reaction and determining the time required for the reaction completion (t1/2=9.83 min at 304K, 10.44 min at 294K, 10.93 min at 284K, and 11.57 min at 274K). The study results demonstrated that half-life values are inversely proportional to reaction rate constants as temperature increases under identical conditions. The low activation energy value (Ea=4.107kJ/mol) indicates that the formation reaction proceeds rapidly and spontaneously without the need for catalysts a feature that enhances its industrial economic viability.