The exploration of equivalent alkane carbon number of molecules

Abstract

This work strives to be a useful compilation of hydrophilic-lipophilic deviation (HLD) information with a focus on explaining the current understanding of Equivalent Alkane Carbon Number (EACN). The industrial interests in microemulsions and the benefits of the HLD equation were argued for. The history and various forms of the HLD equation as well as its applicability to many different surfactant-oil-water (SOW) systems was shared to show its worthiness in continued research. The status of surfactant research was briefly discussed to uphold the versatility of the HLD equation. A significant amount of research was done to compile reported EACN values and the methods of obtaining the EACN of many different oils. The methods of calculating the surfactant’s characteristic curvature Cc and the oil’s EACN, as well as several coefficients in the HLD equation, were compared. For EACN values the fish-tail temperature method is the most accurate and reliable, and EACN data from this method was used to study trends related to the structure and functionalization of the oil. Several simple trends for predicting EACN are reported for structurally similar oil family. In addition, a model for predicting the EACN of alkyl alkanoates was proposed. Finally, examples of predicting EACN of an oil based on the contribution of functional groups, which is dependent on the location and presence of other functional groups.