Inhibiting corrosion of aluminium or its alloys - exposed to weakly acidic ammonium sulphate soln., by adding neutralised condensate of di:bromo-propanol and phosphorus pent:oxide to soln.

摘要

The corrosion of Al and Al alloys in ammonium sulphate contg. solns. at 0-30 degrees C is inhibited by adding to the weakly acidic soln. at pH 2-4, a condensn. prod. of dibromopropanol and phosphorus pentoxide. The inhibitor is prepd by heating a mixt. of 2-3 moles dibromopropanol and 1 mole phosphorus pentoxide until a clear soln. is obtd., and neutralising the reaction prod. with ammonium and/or another alkali hydroxide or -carbonate. The inhibitor is added to the weakly acid ammonium sulphate soln. at a concn. of 0.5-20 wt.% based on the ammonium sulphate content. Levels below 0.5 wt.% are not effective and higher ones are only useful if the ammonium sulphate concn. is very low. The soln. may contain, in addn., a fire-proofing agent and an anionic or non-ionic wetting agent.