Document Type : Original Article


1 Department of Chemistry, Mangalore University, Mangalagangotri-574199, Karnataka, India

2 Department of Chemistry, Vivekananda College of Engineering and Technology, Puttur-574203, Karnataka, India


Theobroma cocoa dry bean extract (CDBE) was prepared by Soxhlet extraction method and was characterized for its chemical constituents using Fourier Transform-Infrared Spectroscopy (FT-IR), Gas chromatography-Mass spectroscopy (GC-MS) and also by Thermogravimetric Analysis-Differential Scanning Calorimetry (TGA-DSC) techniques. FT-IR analysis gave information about the mostly like to be present functional groups in the extract. GC-MS analysis of the extract revealed the presence of important 07 chemical constituents with cis-13-octadecanoic acid as the major component. TGA-DSC study gave the idea about different stages of thermal decomposition of the chemical constituents present in the extract. CDBE was then tested for its ability to inhibit the corrosion rate of mild steel in 1.0M HCl solution medium by means of weight loss, Potentiodynamic polarization, and Electrochemical impedance spectroscopy (EIS) techniques. The weight loss experiments revealed the anticorrosive property of it on mild steel, which was found to increase with increase in the concentration of the inhibitor CDBE and decrease with an increase in temperature of corrosive medium. EIS results showed the adsorption of organic constituents present in the extract at the metal-solution interface. Potentiodynamic polarization studies revealed that CDBE functioned as a mixed type inhibitor. The surface morphological studies of mild steel surface were carried out by Scanning electron microscopy (SEM). The inhibition efficiency values obtained by electrochemical measurements were consistent with those from weight loss measurements and hence it can be proposed that CDBE as a potent inhibitor towards corrosion of mild steel under acidic conditions.


  1. Tiwari, B.K., Brunton, N.P. and Brennan, C. eds., 2013. Handbook of plant food phytochemicals: sources, stability and extraction. John Wiley & Sons. 
  2. John. R. Dyer, 1989. Applications of Absorption Spectroscopy of Organic Compounds, Prentice Hall of India.
  3. Pretsch, E., Buehlmann, P., Affolter, C., Pretsch, E., Bhuhlmann, P. and Affolter, C., 2000. Structure determination of organic compounds. Berlin: Springer-Verlag. 
  4. Wang, J. and Zhang, Z., 1994. Analytical chemistry. VCH, New York.
  5. Willard, H.H., Merritt, L. and Dean, J.A., 1988. Instrumental methods of analysis. In Instrumental methods of analysis. Wadsworth. 
  6. Fifield, F.W., 2000. Principles and practice of analytical chemistry. Blackwell science ltd.
  7. Perez, N., 2004. Electrochemistry and corrosion science (Vol. 412). Boston: Kluwer Academic Publishers.
  8. Ahmad, Z., 2006. Principles of corrosion engineering and corrosion control. Elsevier. 
  9. McCafferty, E., 2010. Introduction to corrosion science. Springer Science & Business Media. 
  10. Hasson, D., Shemer, H. and Sher, A., 2011. State of the art of friendly “green” scale control inhibitors: a review article. Industrial & Engineering Chemistry Research50(12), pp.7601-7607.
  11. Raghavendra, N. and Bhat, J.I., 2016. Green approach to inhibition of corrosion of aluminum in 0.5 M HCl medium by tender arecanut seed extract: insight from gravimetric and electrochemical studies. Research on Chemical Intermediates42(7), pp.6351-6372.
  12. M’hiri, N., Veys-Renaux, D., Rocca, E., Ioannou, I., Boudhrioua, N.M. and Ghoul, M., 2016. Corrosion inhibition of carbon steel in acidic medium by orange peel extract and its main antioxidant compounds. Corrosion Science102, pp.55-62.
  13. Njoku, V.O., Oguzie, E.E., Obi, C. and Ayuk, A.A., 2014. Baphia nitida leaves extract as a green corrosion inhibitor for the corrosion of mild steel in acidic media. Advances in Chemistry2014, pp.1-11.
  14. Kumar, K.P., Pillai, M.S. and Thusnavis, G.R., 2010. Pericarp of the fruit of Garcinia Mangostana as corrosion inhibitor for mild steel in hydrochloric acid medium. Portugaliae Electrochimica Acta28(6), pp.373-383. 
  15. A Negm, N., A Yousef, M. and M Tawfik, S., 2013. Impact of synthesized and natural compounds in corrosion inhibition of carbon steel and aluminium in acidic media. Recent Patents on Corrosion Science3(1), pp.58-68.
  16. Singh, A., Ebenso, E.E. and Quraishi, M.A., 2012. Corrosion inhibition of carbon steel in HCl solution by some plant extracts. International Journal of corrosion2012, pp.1-20.
  17. Gerengi, H. and Sahin, H.I., 2011. Schinopsis lorentzii extract as a green corrosion inhibitor for low carbon steel in 1 M HCl solution. Industrial & Engineering Chemistry Research51(2), pp.780-787.
  18. Othman, A., Ismail, A., Ghani, N.A. and Adenan, I., 2007. Antioxidant capacity and phenolic content of cocoa beans. Food chemistry100(4), pp.1523-1530.
  19.  Proestos, C., Zoumpoulakis, P. and Sinanoglou, V.J., 2018. Isolation and Characterization of Phenolic Compounds From Selected Foods of Plant Origin Using Modern Spectroscopic Approaches. In Studies in Natural Products Chemistry  (Vol. 57), Elsevier, pp. 203-220.
  20. Yetri, Y. and Jamarun, N., 2015. Corrosion inhibitorof mild steel by polar extract of theobroma cacao peels in hydrochloric acid solution. Asian Jurnal of Chemistry27(3), pp.876-881.
  21. Chaithra, P., Hemashree, K. and Bhat, J.I., 2016. An Investigation on the Attack of Dye Species on Freshly Synthesized and Characterized Activated Carbon from Cocoa Pod. Iranica Journal of Energy and Environment7(4), pp.350-358.
  22. Sermakkani M. And V. Thangapandian P.G., 2012. Gc-ms analysis of cassia italica leaf methanol extract. Asian Journal of Pharmaceutical and Clinical Research. 5(2) pp.90-94.
  23. Rao, V. and Johns, J., 2008. Thermal behavior of chitosan/natural rubber latex blends TG and DSC analysis. Journal of Thermal Analysis and Calorimetry92(3), pp.801-806. 
  24. Bhat, J.I. and Alva, V.D., 2011. Meclizine hydrochloride as a potential non-toxic corrosion inhibitor for mild steel in hydrochloric acid medium. Archives of Applied Science Research3, pp.343-356.
  25. Bhat, J.I. and Alva, V., 2009. Corrosion inhibition of aluminium by 2-chloronicotinic acid in HCl medium. Indian Journal of Chemical Technology16(3), pp.228-233.
  26. Hemashree, K. and Bhat, J.I., 2017. Synthesis, characterization and adsorption behavior of coconut leaf carbon. Research on Chemical Intermediates43(8), pp.4369-4386.
  27. Ating, E.I., Umoren, S.A., Udousoro, I.I., Ebenso, E.E. and Udoh, A.P., 2010. Leaves extract of Ananas sativum as green corrosion inhibitor for aluminium in hydrochloric acid solutions. Green Chemistry Letters and Reviews3(2), pp.61-68.
  28. Ekanem, U.F., Umoren, S.A., Udousoro, I.I. and Udoh, A.P., 2010. Inhibition of mild steel corrosion in HCl using pineapple leaves (Ananas comosus L.) extract. Journal of materials science45(20), pp.5558-5566.
  29. Oguzie, E.E., Njoku, V.O., Enenebeaku, C.K., Akalezi, C.O. and Obi, C., 2008. Effect of hexamethylpararosaniline chloride (crystal violet) on mild steel corrosion in acidic media. Corrosion Science50(12), pp.3480-3486.
  30. Hamdy, A.S., El-Shenawy, E. and El-Bitar, T., 2006. Electrochemical impedance spectroscopy study of the corrosion behavior of some niobium bearing stainless steels in 3.5% NaCl. International Journal of Electrochemical Science1(4), pp.171-180.
  31. Ashassi-Sorkhabi, H. and Es’haghi, M., 2009. Corrosion inhibition of mild steel in hydrochloric acid by betanin as a green inhibitor. Journal of Solid State Electrochemistry13(8), pp.1297-1301.
  32. Döner, A., Solmaz, R., Özcan, M. and Kardaş, G., 2011. Experimental and theoretical studies of thiazoles as corrosion inhibitors for mild steel in sulphuric acid solution. Corrosion Science53(9), pp.2902-2913.
  33. Bentiss, F., Traisnel, M. and Lagrenee, M., 2000. The substituted 1, 3, 4-oxadiazoles: a new class of corrosion inhibitors of mild steel in acidic media. Corrosion science42(1), pp.127-146.
  34. Mistry, B.M., Patel, N.S., Patel, M.J. and Jauhari, S., 2011. Corrosion inhibition performance of 1, 3, 5-triazinyl urea derivatives as a corrosion inhibitor for mild steel in 1 N HCL. Research on Chemical Intermediates37(6), pp.659-671.