An experimental study of the mass transfer rates in single drops with simultaneous Marangoni convection was carried out, using a system in which acetic acid was transferred from water to n-propyl acetate. In all experimental trials, high purity deionized water was employed as the continuous phase while n-propyl acetate served as the dispersed phase. The effects of both the drop diameter and the initial solute concentration in the continuous phase on the mass transfer were examined. The results demonstrated that mass transfer is increased as the drop size decreases and exhibits a maximum at an acetic acid concentration in the aqueous solution of 0.15 g/ml which reveals the competing mechanisms between reduction of velocity and mass transfer enhancement due to Marangoni effects. All current models, including the Newman (1931) model, do not account for the influence of the initial solute concentration, and thus a correction factor, a, was introduced to obtain the factor, R', by which the effective diffusivity is enhanced, based on Steomer's (1986) modified Newman model. This alpha factor is a function of the initial difference in solute concentration. The mass transfer rates predicted by our modified Newman model were in good agreement with the experimental data obtained in the present study. (c) 2014 Elsevier Ltd. All rights reserved