The isoxazolidines: a new class of corrosion inhibitors of mild steel in acidic medium

The cycloaddition of the cyclic nitrone-1-pyrroline-1-oxide with a variety of alkenes, phenyl isocyanate and phenyl isothiocyanate afforded a multitude of cycloaddition products (isoxazolidines). One of the cycloadducts on reaction with benzyl and propargyl chloride gave quaternary ammonium salts. All these new isoxazolidines are tested for corrosion inhibition of mild steel in 1 M HCl at 60 degreesC by gravimetric and electrochemical methods. The inhibition efficiency of this class of compounds are determined for the first time. All compounds have shown excellent corrosion inhibition efficiency (IE%) in acidic solution; IE% in the range 86.7-99.5 are measured by the gravimetric method. Comparable results were obtained by the electrochemical method using Tafel plots for the inhibition efficiency of some of the selected synthesized compounds. (C) 2002 Elsevier Science Ltd. All rights reserved.