Preparation and evaluation of some new corrosion inhibitors in varnishes

Soybean oil was epoxidized in situ under established conditions. The produced epoxidized soybean oil was subjected to a sulfur containing compound of the formula (5-phenyl-1,3,4-oxadiazole-2-(3H)-thiones) and four of its derivatives (p-chloro-, p-iodo-, p-methyl- and p-methoxy-) in sealed ampoules under inert atmosphere at 180-230 degreesC (according to the melting point of each sulfur compound). The produced adducts were added to three varnishes based on alkyd resin, chlorinated rubber and a Vinyl chloride copolymer to evaluate them as corrosion inhibitors for steel surfaces. It was found that these adducts can act as good corrosion inhibitors and their efficiencies depend principally on the substituted functional group.