Volume No. 7 Issue No.: 4 Page No.: 1369-1373 April-June 2013

 

LANGMUIR ADSORPTION ISOTHERM AND REACTION NUMBER EVALUATION FOR MILD-STEEL IN BINARY ACID (HCL+H2SO4) MIXTURE IN PRESENCE OF TOLUIDINE ISOMERS

 

Tandel P.R.*1, Oza B.N. 2 and Mali N.J.3

1. Department of Chemistry, Navyug Science College, Rander Road, Surat (INDIA)
2. Department of Chemistry, VNSG University, Surat (INDIA)
3. Department of Chemistry, B.K.M. Science College, Valsad (INDIA)

 

Received on : December 01, 2012

 

ABSTRACT

 

Corrossion behaviour of mild-steel in binary acid (HCl+H2SO4) mixture has been examined using conventional weight-loss and thermometric techniques in presence of substituted aniline compound viz. o-toluidine, p-toluidine and m-toluidine. These inhibitors obey Langmuir Adsorption Isotherm equation (i) Reaction Number (RN), (ii) temperature difference as well as (iii) time to reach Tmax were calculated by thermometric technique. Inhibition efficiency determined from the result of weight-loss and thermometric techniques are in good agreement for toluidine isomers used in the binary acid mixture. The mode of inhibitive action appears to be chemisorption. Toluidine isomers can be arrange in the following order of efficiency in inhibiting corrosion of mild-steel. o-toluidine > p-toluidine > m-toluidine. Comparatively higher inhibition efficiency by ortho and para-isomer of toluidine can be attributed to the tendency for surface protonation due to high hydrogen over voltage on metal surface.

 

Keywords : Reaction Number (RN), Inductive effect, Resonance states, Chemisorption, Aniline

 

 

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