Inhibition of copper corrosion by bis-(1,1′-benzotriazoly)-α,ω-diamide compounds in aerated sulfuric acid solution

Three kinds of novel corrosion inhibitors, bis-(1,1′-benzotriazoly)-α,ω-succinyldiamide (BSU), bis-(1,1′-benzotriazoly)-α,ω-adipoyldiamide (BAD), and bis-(1,1′-benzotriazoly)-α,ω-azelayldiamide (BAZ) were synthesized and certified by IR and ¹H NMR. Their corrosion inhibition effects for copper in 0.5 M H₂SO₄ were evaluated by weight-loss method. It shows that among the three compounds, only BSU behaves better compared with BTA. The inhibition efficiency (IE) increased with increasing BSU concentration to 85.2% at the 5 × 10⁻⁴ M level. Polarization studies showed that BSU suppressed both anodic and cathodic corrosion reactions. The minimum energy conformation of these compounds was obtained by MM2 force field program. The two benzotriazoly moieties in BSU molecule are more parallel than in other compounds. This is benefit to increase the inhibition effects of BSU.