RESULTS
The neutralization numbers and the interfacial tension
values obtained after subjecting oil samples containing one
of each of the seven antioxidants to standard aging
conditions are indicated in Figures 2 and 3.
Excluding the case where a copper strip was placed in the
mineral oil sample that contained DBDS the highest
neutralization numbers and in turn the highest acid contents
where those observed for the mineral oil solutions that
contained methylated BTA and 2-tert-butyl-p-cresol. BTA
gave rise to relatively high neutralization numbers
compared to the remaining antioxidants. Clearly the most
efficient antioxidants are DBDS, DBPC, DBP and Nphenyl-
1-naphthylamine.