دراسة فعالية التثبيط لبعض المركبات العضوية الكبريتية و الآزوتبة

Abstract

The present work deals with a study of inhibitor activity of four organonitrogen and sulfiric compounds against CX52 steel corrosion in a 20% concentrated acidic solution. These compounds are : (1) 5 methylbenzotriazol (B1), (2) 2 mercaptobenzimidazol (B2), (3) 4 phenyl -1,2 dithiol -3 thione (A1), (4) 4 p.tolyl -1,2 dithiol -3 thione (A2). The procedure has been carried out by dissolving compounds B1 and B2 in a 4% ethanol solution and compounds A1 and A2 in a 6% one without and then with the presence of inhibitor. Two methods have been adopted: the first is chemical and consists of the weight loss by immersing the steel sample in the solution where as the second is electrochemical and deals with plotting Taffel curves.The obtained results revealed that the studied compounds exhibit different inhibition behaviours. Compound B1 displayed the best efficiency ( 94.23% ) corresponding to a 10 mg/l. compound A2, however, showed about the same protection 94,15% with 30 mg/l. Although, compound A1 has not excerded 76,62% with 20mg/l, compound B2 was the least inhibitive with no more than 19% with 160mg/l . The use of these compounds as inhibitors was confronted with a set of difficulties amongst which the concederable amounts of ethanol used : 40 l/m3 for nitrogen compounds, and 60 l/m3 for sulfuric compounds, and hence , make them hughly expensive for use.