Universal Phase Transformation Mechanism and Substituted Alkyl Length and Number Effect for the Preparation of Overbased Detergents Based on Calcium Alkylbenzene Sulfonates

Abstract

Overbased calcium sulfonate is one of the largest commercially produced nanomaterials; the phase transformation mechanism involved in the key process of carbonation reaction for overbased detergent preparation has not yet been fully understood. Following our previous investigation based on the heavy alkylbenzene sulfonate (HABS) surfactant of industrial byproduct, two commercial products with well-defined chemical compositions and structures, long-chain alkylbenzene sulfonate (LCABS) and comparative short-chain linear alkylbenzene sulfonate (SLABS), are employed in this study as model surfactants for further mechanism study of this pivotal process by the combination of analytical techniques such as potentiometric titration, DLS, TEM, FTIR, and XRD. It has been demonstrated that amorphous calcium carbonate (ACC) is a prerequisite for the preserving and stabilization of the alkaline reserve, especially under thermal work environment. The phase transformation from ACC to crystalline vaterite polymorph rather...