Krafft Point Prediction of Anionic Surfactants Using Group Contribution Method: First‐Order and Higher‐Order Groups

Abstract

AbstractKrafft point is one of the key properties of anionic surfactants to indicate their solubility in an aqueous phase. Below the Krafft point, the surfactant is a useless solid. We have developed a prediction model for the Krafft point based on the Marrero and Gani Group Contribution (GC) concept. Literature data were analyzed and a new third‐order level was proposed to improve the model accuracy. The Krafft points of 53 anionic surfactants were collected including alkyl sulfonate, alkyl sulfate, alkyl benzene sulfonate, alkyl ethoxy sulfate, alkyl ester sulfonate, alkyl ester sulfate, alkyl disulfate, alkyldiphenylether disulfonates, alkyl diester sulfonate, alkyl naphthalene sulfonate, and fluorocarbon surfactants. The coefficients of the fractional groups in a surfactant molecule reveal the dependence of the Krafft point on the internal structure. Compared to the more complicated models such as those based on advanced statistical concept, the GC model for the Krafft point developed in this work gives a higher accuracy with a simpler calculation.