Recovery of carbon monoxide from flue gases by selective absorption of carbon monoxide in an imidazolium chlorocuprate(I) ionic liquid is considered in this work as an alternative to the use of molecular volatile solvents such as aromatic hydrocarbons. The present work evaluates the CO mass transfer rates from the gas phase to the ionic liquid solutions in the absence of chemical reaction. To that end, carbon dioxide was employed as an inert model gas and absorption experiments were performed to assess the influence of different process variables in a batch reactor with flat gas-liquid interface. The experimental mass transfer coefficients showed significant variation with temperature, (3.4-10.9) x 10(-7) m center dot s(-1) between 293 and 313 K; stirring speed, (10.2 - 33.1) x 10(-7) m center dot s(-1) between 100 and 300 r center dot min(-1); and concentration of copper(I), (6.6-10.2) x 10(-7) m center dot s(-1) between 0.25 and 2 mol center dot L-1. In addition, the mass transfer coefficients were eventually found to follow a potential proportionality of the type kL. proportional to mu(-0.5) and the dimensionless correlation that makes the estimation of the mass transfer coefficients possible in the studied range of process variables was obtained: Sh = 10(-2.64) center dot Re-1.07 center dot Sc-0.75. These results constitute the first step in the kinetic analysis of the reaction between CO and imidazolium chlorocuprate(I) ionic liquid that determines the design of the separation units. (C) 2015 The Chemical Industry and Engineering Society of China, and Chemical Industry Press. All rights reserved.