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Novel classes of organic corrosion inhibitors. Dr. S. U. Rahman Associate Professor, Chemical Engineering Department King Fahd University of Petroleum & Minerals, Dhahran-31261, Saudi Arabia. Applications of Corrosion Inhibitors. Water Potable Water Silicates, Popyphosphates, CaCO 3
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Novel classes of organic corrosion inhibitors Dr. S. U. Rahman Associate Professor, Chemical Engineering Department King Fahd University of Petroleum & Minerals, Dhahran-31261, Saudi Arabia
Applications of Corrosion Inhibitors • Water • Potable Water • Silicates, Popyphosphates, CaCO3 • Cooling Water • Chromate, Nitrate, Polyphosphates, • Automotive Coolants • Nitrite, Benzoate, Borax, • Steam Condensates • Mophines, cyclohexamine, Long chain aliphatic amines • Brine and Seawater • Nitrite, Chromates, Phosphates • Acid Pickling • Sulfur and nitrogen containing organic compounds • Oil Production and Refining • Sulfur and nitrogen containing organic compounds
Factors Affecting Inhibition of Cooling Systems • Oxygen saturation • Water soluble gases • pH • TDS • Silt and Solids • Sulfate bearing Bacteria
Requirements of Inhibitors • Surface coverage • Low concentration • Wide range of conditions (T, pH and water quality) • Should not produce solid deposits • Low/nil toxicity • Antiscaling properties
New Classes of Inhibitors • Isoxazolidines1 • Cyclic Hydroxylamines2 • Cyclic Nitrones3 1 Ali, A. A., Saeed, M. T., Rahman, S. U., Corrosion Science, 45 (2003) 253-266. 2 Saeed, M. T., Ali, A. A., Rahman, S. U., Anti-Corrosion Methods and Materials, 50 (2003) 201-207. 3 Rahman, S. U., Saeed, M. T., Ali, S. A, Anti-Corrosion Methods and Materials (Accepted).
Isoxazolidines1 Nitrone isoxazoidines Diadducts Cycloadducts 1 Ali, A. A., Saeed, M. T., Rahman, S. U., Corrosion Science, 45 (2003) 253-266.
Quaternary Ammonium Salts1 Quaternary Amm. Salt Isoxazolidine Quaternary Amm. Salt 1 Ali, A. A., Saeed, M. T., Rahman, S. U., Corrosion Science, 45 (2003) 253-266.
Summary of all isoxazolidines isoxazoidines Cycloadducts Quaternary Ammonium Salts Diadducts 1 Ali, A. A., Saeed, M. T., Rahman, S. U., Corrosion Science, 45 (2003) 253-266.
Gravimetric Tests (Inhibition Efficiencies) Substrate metal : Mild steel, Temperature : 60 C, Exposure : 6 hrs, Base solution : 1 N HCl asoluble in 10% acetone in 1N HCl b%IE for 10 and 25 ppm were 87.2 and 91.8, respectively.
Tafel Tests Substrate metal : Mild steel, Temperature : 60 C, Exposure : 20 minutes, Base solution : 1 N HCl, Inhibitor Concentration : 400 ppm 1 Ali, A. A., Saeed, M. T., Rahman, S. U., Corrosion Science, 45 (2003) 253-266.
Cyclic Hydroxylamines2 Hydroxylamines Nitrone Hydroxypyrrolidine Cyclic Nitrones Hydroxylamines Hydroxylamines 1 Saeed, M. T., Ali, A. A., Rahman, S. U., Anti-Corrosion Methods and Materials, 50 (2003) 201-207.
Hydroxylamines 1 Saeed, M. T., Ali, A. A., Rahman, S. U., Anti-Corrosion Methods and Materials, 50 (2003) 201-207.
Gravimetric Tests (Inhibition Efficiencies) Substrate metal : Mild steel, Temperature : 60 C, Exposure : 6 hrs, Base solution : 1 N HCl asoluble in 10% acetone in 1 N HCl; d %IE for inhibitor concentration of 10 and 25 ppm was determined to be 26.7 and 62.5, respectively.
Tafel Tests Substrate metal : Mild steel, Temperature : 60 C, Exposure : 20 minutes, Base solution : 1 N HCl, Inhibitor Concentration : 400 ppm 1 Saeed, M. T., Ali, A. A., Rahman, S. U., Anti-Corrosion Methods and Materials, 50 (2003) 201-207.
Cyclic Nitrones3 1 Rahman, S. U., Saeed, M. T., Ali, S. A, Anti-Corrosion Methods and Materials (Accepted).
Gravimetric Tests (Inhibition Efficiencies) Substrate metal : Mild steel, Temperature : 60 C, Exposure : 6 hrs, Base solution : 1 N HCl asoluble in 10% acetone in 1N HCl
Tafel Tests1 1 Rahman, S. U., Saeed, M. T., Ali, S. A, Anti-Corrosion Methods and Materials (Accepted).
Conclusions • Following new compound exhibited excellent corrosion inhibition of mild steel in hot acidic medium: Polar compounds with substantially bulky non-polar chains were better inhibitors. Isoxazolidines Cyclic Hydroxylamines Cyclic Nitrones
Future work • Gather more data in different corrosive environments. • Use mixtures of these compounds. Statistical experimental design will be beneficial • Perform toxicity studies • Study their anti-scalent properties. • Study their synergy with commercial anti-scalents.
Acknowledgement • Prof. S. A. Ali, • Dr. M. T. Saeed,