Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7842679 | Journal of Molecular Liquids | 2018 | 24 Pages |
Abstract
The effect of surfactants (sodium dodecyl sulphate; SDS, cetyltrimethyl ammonium bromide; CTABr, and Triton X-100; TX100) and polymeric surfactants (viz. polyethylene glycol; PEG) mixture on the rate of base catalyzed hydrolysis of procaine hydrochloride (2-diethylaminoethyl-4-aminobenzoic acid) has been studied under the pseudo-first-order conditions ([OH¯] â«Â [Procaine]). The rate of hydrolysis of procaine was found to be linearly dependent upon the [NaOH] in the range from 2.0 Ã 10â2 mol dmâ3 to 8.0 Ã 10â1 mol dmâ3 at fixed [procaine] (=5.0 Ã 10â5 mol dmâ3) at 37 °C. The values of rate constant were found to be independent on [procaine] in the concentration range from 1.0 Ã 10â5 mol dmâ3 to 1.0 Ã 10â4 mol dmâ3 at a fixed concentration of NaOH at 5.0 Ã 10â2 mol dmâ3. The values of rate constant decreased with the increase in the concentrations of surfactants (SDS, CTABr and TX100). The rate of hydrolysis further decreased with the addition of PEGs of different molecular weights (1500, 4000, 6000 and 8000) in the reaction media containing surfactant. The increase in the concentration of PEGs from 1% to 5% decreased the rate of hydrolysis, thereby, increasing its stability. The increase in molecular weight of PEG also decreased the rate of hydrolysis. The kinetic parameters and binding constants (e.g. km, Kp for the different reaction media) were calculated for the reactions occurring in the aqueous and surfactant-PEG pseudophases by applying pseudophase ion exchange model. Maximum inhibition in the rate of hydrolysis was observed for PEG-TX100 aggregates.
Related Topics
Physical Sciences and Engineering
Chemistry
Physical and Theoretical Chemistry
Authors
Kashif Raees, Mohd. Shaban Ansari, M.Z.A. Rafiquee,