Studies on petroleum sulphonates: Correlation between their chemical structure and the oil—Water emulsion stability characteristics

Abstract

The average molecular weight distribution, emulsion stability of oil—water emulsion, the chemical structure of the hydrocarbon portions of petroleum sulphonates, and surface active properties have been determined with a view to establishing a correlation between the chemical structure of petroleum sulphonates and their emulsion stability characteristics. It has been found that the emulsion stability of oil—water emulsions imparted by sodium petroleum sulphonates depends on: (i) average molecular weight of sodium petroleum sulphonates; (ii) their molecular weight distribution; (iii) oil—water interfacial tension; (iv) hydrophile—lipophile balance values. The structural parameters which predominantly effect the emulsion stability are the ratio of the percentage distribution of carbon atoms in paraffin side chains to the percentage distribution of carbon atoms, the aromatic rings (CP/CA), the relative proportions of long chain mono‐aromatics and the orientation of the sulphonate group relative to the paraffin alkyl chains in the molecules.