Performance of commercial antioxidants in white mineral oils

Abstract

Purpose The aim of this paper is to study the effects of commercially available antioxidants on the oxidation stability of white mineral oils (paraffin oil). Design/methodology/approach Twelve commercially available antioxidants (Chimassorb 81, Tinuvin 326, Tinuvin 765, Tinuvin 571, Irganox L57, Irganox L109, Irganox L101, Irganox L115, Irganox L06, Irgafos 168, Naugard 445, BHT) were added to pharmaceutical and technical grade white mineral oils at 0.1%, 0.2%, 0.3%, 0.6% and 0.8% (w/w) concentrations. Light, heat and oxygen were applied to induce and accelerate oxidation. Total acid number, viscosity and 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity of the oils were measured to evaluate the performance of the antioxidant additives. Findings Results showed that combined heat and oxygen treatment was the most effective of the three conditions tested to cause oxidation. Based on the data, the best antioxidant additives to be used in white oils are decided to be Irganox L06 and Irganox L101. It was also found that the grade of oils (technical or pharma) did not create a significant difference in the results obtained. Originality/value To the best of the authors’ knowledge, this is the first study that reports effects of antioxidant addition on the oxidative properties of white mineral oils. This study advances knowledge of the behavior of white mineral oils under real atmosphere and provides comprehensive data on how the antioxidants affect the light, thermal, oxidative degradation of white mineral oils. The data presented also provide an insight to extend life expectancy of white mineral oils.