Sulphonates as rust inhibitors

Abstract

The rust inhibiting characteristics of barium/calcium petroleum sulphonates, prepared from two indigenously available base stocks of different origin have been determined in concentration ranging from 0.5 to 3.0% W/W in mineral oil as per ASTM D‐1748 method. The products have been characterised as ‘outstanding’, ‘good’ and ‘satisfactory’ on the basis of their performance in the humidity cabinet. It has been observed that Ba/Ca petroleum sulphonates possessing outstanding rust inhibiting characteristics show low oil/water interfacial tension and high water solubilization characteristics as compared to other sulphonates. It has also been observed that the rust inhibiting characteristics are profoundly influenced by the structural parameter of the hydrocarbon portion of the petroleum sulphonates. The larger the alkyl side chain, the better is the rust inhibiting properties.