Chemiluminescence: A tool to determine the rate constant and order of chemical reactions

 

V.K. Jain*

Department of Chemistry, Pt. Shyamacharan Shukla College, Dharsiwa, Raipur (C.G.)

*Corresponding Author E-mail: vikaskumarjain1@rediffmail.com

The chemiluminescence (CL) intensity in a given system is proportional to the concentration of reactants and the rate of elementary reaction.  Measuring the CL-intensity, one can get rate constant and order of chemical reaction.  The attenuation of the CL takes place by an exponential law for first order CL-reaction and consequently, the rate constant can be found from the slope of the lnI versus time curves.

 

INTRODUCTION:

The emission of cold light during chemical processes is known as chemiluminescence (CL).  It arises from the excited states of products of an exothermic reaction.  The intensity of light in a given system is proportional to the rate of elementary reaction responsible for the luminescence. Chemiluminescence is observed mainly in reactions of two types : (i) in the gas phase reactions taking place at high rates with high concentrations of atoms and free radicals (reactions in flames, reactions of atomized gases etc.), and (ii) in the oxidation of organic and inorganic substances with molecular oxygen, peroxides and other oxidizing agent [1-6]. There are so many examples of chemiluminescence- reactions.  In most cases, the quantum yield of CL, which is the ratio of the number of light quanta emitted to the number of product molecules formed, does not exceed 0.001-0.1%. However for several other chemiluminescence-reactions e.g. the specially substituted oxamide or dioxetane intermediates, it can reach 30%.  Another example of chemiluminescence reactions is in living organisms e.g. fire-fly.

 

The present paper reports that CL can be used as a tool to determine the rate constant and order of chemical reactions.

 

CONCLUSION:

The rate constant and order of reaction can be measured by measuring the time decay of CL-intensity.

 

REFERENCES:

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(3)     L. Campbell, L.J. Kricka, and P.E. Stanley, Bioluminescence and Chemiluminescence : Current status (Wiley, Chichester) (1994).

(4)     J.H. Devine, G.D. Kutuzova, V.A. Green, N.N. Ugarova, and T.O. Baldwin, Biochem. Biophys. Acta. 1173, 121 (1993).

(5)     A.A., Szalay, L.J. Kricka, and P.E. Stanley, Bioluminescence and Chemiluminescence : Status Report (Wiley, Chichester) (1993).

(6)     N.N. Ugarova, L. Yu Brovko and E.I. Dementieva, Luminescence of Solids, Edited by D.R. Vij, Plenum press, New York (1998).

(7)     V.Ya Shlyapintokh, Chemiluminescence techniques in chemical reactions, Consultants Bureau, New York, 67-73 (1968).

 

 

 

Received on 20.04.2013       Modified on 11.05.2013

Accepted on 20.05.2013      © AJRC All right reserved