Determination of the sorption and desorption kinetics of perfume raw materials in the liquid phase with vesicular dispersion: Application of SIFT-MS

Abstract

Perfume raw materials such as coumarin, hexyl acetate and octanal are used in domestic fabric softeners together with cationic quaternary ammonium surfactants during the last rinsing step of a wash cycle. Selected ion flow tube mass spectrometry (SIFT-MS) is used to analyze the gas phase concentration of these perfume raw materials in an experiment, mimicking this rinsing step when fabric softeners are applied together with a vesicular diethyl ester dimethyl ammonium chloride (DEEDMAC) dispersion in a bubble column. A continuous stirred tank reactor (CSTR) model is proposed to obtain sorption and desorption kinetics for the mass transfer between the liquid phase and the vesicular dispersion from experimental gas phase concentration data. Sorption coefficients of (4.8±0.3) 10−3, (9.4±0.1) 10−3 and (4.0±0.1) 10−3s−1 are obtained for coumarin, hexyl acetate and octanal. Desorption coefficients for these components are respectively reported as (5.4±0.6) 10−5, (1.8±0.1) 10−5 and (3.5±0.2) 10−5s−1. From an engineering point of view, SIFT-MS is considered to be a promising experimental technique to evaluate the dynamic behavior, i.e., the sorption and desorption kinetics, of molecules in a vesicular dispersion using the proposed CSTR model.