Kinetic study of complex formation of silver (I)‎ with Ortho-aminobenzoic acid in micellar and microemulsion phases

Abstract EN

Kinetic study concerning the complex formation of silver ion (Ag+) with Ortho-aminobenzoic acid(OABA) was conducted.

The reaction kinetics was studied in aqueous, micellar solutions and L2 microemulsion media of different surfactants.

Sodium dioctylsulfosuccinate (AOT), cetyltrimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS) were the studied surfactants.

Spectrophotometric study follow up at 460 nm was used.

The results show that the reaction is first-order with respect to Ag+ and OABA in all cases.

Generally; values of the observed rate constants (kobs) were increasing with increasing of surfactant concentration in micellar media.

AOT media was mainly more promotional than each of SDS and CTAB.

A pseudo-phase kinetic model was applied and association constants of Ag+ and OABA with surfactant micelles were calculated.

Values of kobs for the reaction rates in microemulsion phases have been reported.

AOT L2 microemulsion system has been found as the most promotional system among all the other studied systems.

Association constants of Ag+ and OABA with surfactant layer in microemulsion were calculated and tabulated.

The reaction rate was increasing by increasing temperature in aqueous, micellar and microemulsion phases.

The activation parameters h*, S* and G* have also been obtained.

The reaction rate in different microemulsion media is affected by oil nature (n-heptane > n-hexane > npentane).

Co-surfactants nature (n-butanol, n-pentanol and n-hexanol) has a very slight effect on kobs values in the case of CTAB or SDS microemulsion.