GB1434354A - Inhibition of corrosion - Google Patents

Abstract

1434354 Inhibiting corrosion; treating metal surfaces IMPERIAL CHEMICAL INDUSTRIES Ltd 26 July 1973 [17 Aug 1972] 38412/72 Headings C7E and C7U Corrosion of steel or Al by acidic compounds is inhibited by adding to the compound an azomethine, or by pre-treatment of the metal with an azomethine neat or in solution in a solvent, or with its precursors, or by a combination of these methods. The azomethine (Schiff base), which may have additional C-N unsaturation, in the form of oxime or CN groups, is made of condensing (1) an amine with (2) an aldehyde or ketone; (1) may be MeNH 2 , EtNH 2 , n- or i- BuNH 2 , n- PrNH2, n-hexylamine, stearyl-, octadecyl-, ethanol-, propanol- or cyclohexyl-amine, ethylene-, hexamethylene- or 7-azatridecamethylenediamine, aniline, benzylamine, diaminodiphenylmethane, or a phenylenediamine, and (2) may be acetaldehyde, aldol, propionaldehyde, butyraldehyde, crotonaldehyde, cinnamaldehyde, furfuraldehyde, benzaldehyde, acetone, methyl ethyl ketone, methyl vinyl ketone, methyl isobutyl ketone, benzylidene acetone, xyclohexanone, cyclopentanone, or phenylacetaldehyde. 0À001- 5 wt per cent of inhibitor is added to acids such as formic, acetic, propionic, n-butyric, iso-butyric, stearic, mono-, di-, tri-chloro- or bromo-acetic, lactic, oxalic, succinic, glutanic, adipic, pimelic, terephthalic, suberic, azelaic, sebacic, undecanedioic, dodecanedioic, tartaric, citric, trimesic, sulphurous, sulphuric, hydrochloric, sulphamic or nitric, or organic sulphonic acids in contact with metal, or the inhibitor may be applied neat or in solution in e.g. water, alcohol, acid, base such as pyridine or quinoline, or nitrile, at up to 300‹C; the compound may also be incorporated into paints, waxes, primers or polishes which come into contact with metal.