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Studies on the Kinetics of Thermal Decomposition of Copper Oxalate Mixed With Silver Oxalate

K. Sarada, K. Muraleedharan

Abstract


The coprecipitates, Ag2Cu(C2O4)nH2O of varying composition [Ag = (1 and 2)%], have been synthesized and were characterized by means of IR, XRD, and SEM. The decomposition of the prepared oxalates was monitored by differential scanning calorimetry (DSC) and thermogravimetry (TG). The DSC studies reveal that the decompositions of the mixed oxalates were all complex exothermic processes with resemblance to the exothermic reaction of copper oxalate and ranges from 540 to 600 K. The decomposition kinetics was studied by thermogravimetry at four different heating rates: 5, 10, 15, and 20 K/min. The TG data were subjected to linear least squares analyses (in the range α = 0.1–0.9) using the isoconversional methods of KAS, FWO, Vyazovkin, and Tang to find the values of activation energy (Eα). The activation energies of the pure copper oxalate, in N2 atmosphere, obtained by the above-mentioned methods are 192.1, 191.3, 191.9, and 192.3 kJ/mo1 and that of pure silver oxalate are 179.5, 187.4, 187.9, and 179.9 kJ/mo1, respectively. Copper oxalate coprecipitated with 1% silver oxalate gave activation energy values 206.4, 215.8, 216.6, and 206.9 kJ/mo1 and the coprecipitated with 2% silver oxalate gave activation energy values 182.8, 192.3, 193.1, and 183.3 kJ/mo1. The kinetic analysis of copper–silver oxalates prepared shows a decrease in average activation energy with increase in the concentration of silver oxalate. The variation of activation energy during thermal decomposition reflects the changing mechanism during the course of the reaction. It is observed that the activation energy of copper oxalate is decreased from its original value by the addition of 2% Ag2C2O4. Hence, it will be interesting to study further about the effect of addition of Ag2C2O4 higher than 2%.

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References


Go´rski A, Kras´nicka AD. The importance of the CO2 2- anion in the mechanism of thermal decomposition of oxalates.

J Therm Anal Calorim. 1987;32:1229-41.

Galwey AK, Brown ME. Thermal decomposition of ionic solids: Inorg Chem. 5(1966)214-19.

Donkova B, Avdeev G. Synthesis and decomposition mechanism of c-MnC2O42H2O rods under non-isothermal and

isothermal conditions. J Therm Anal Calorim. 2015;121:567-77.

Hamed MNH, Kamal R. The effect of particle size on the kinetics of thermal decomposition of Co(C2O4)2H2O

nanopowders under non-isothermal conditions. J Therm Anal Calorim. DOI 10.1007/s10973-015-4909-1.

Szirtes L, Megyeri J, Kuzmann E. Thermal treatment on tin(II/IV) oxalate, EDTA and sodium inositol-hexaphospate. J

Therm Anal Calorim. DOI 10.1007/s10973-011-1813-1.

zejowski JB, Zadykowicz B. Computational prediction of the pattern of thermal gravimetry data for the thermal

decomposition of calcium oxalate monohydrate. J Therm Anal Calorim (2013) 113:1497–503.

cetisli H, Cilgi GK, Donat R. Thermal and kinetic analysis of uranium salts. J Therm Anal Calorim. 2012;108:1213-22.

cetisli H, Cilgi GK, Donat R. Thermal and kinetic analysis of uranium salts. J Therm Anal Calorim. 2014;115:2007-20.

Li Y , Wu X, Wu W, Wang K , Qin L, Liao S, Wen Y. Synthesis of CeO2 by thermal decomposition of oxalate

and kinetics of thermal decomposition of precursor. J Therm Anal Calorim. 2014;117:499-506.

Feng Y, Hu T, Pu Z, Wu M, Mi J. Non-isothermal decomposition kinetics of FeC2O42H2O prepared by solid-state

method aiming at the formation of Fe2O3. J Therm Anal Calorim. DOI 10.1007/s10973-015-4757-z.

L’vov BV. The physical approach to the interpretation of the kinetics and the mechanisms of thermal decomposition of solids: the state of art. Thermochim Acta. 2001;373:97–124.

Boldyrev VV. Thermal decomposition of silver oxalate. Thermochim Acta. 2002;388:63–90.

Muraleedharan K, Kripa S. DSC kinetics of the thermal decomposition of copper(II) oxalate by isoconversional and

maximum rate (peak) methods. J Therm Anal Calorim (2014) 115:1969–78.

Donia AM. Synthesis, identification and thermal analysis of co-precipitates of silver-(cobalt, nickel, copper and zinc)

oxalate. Polyhedron. 1997;169:3013-31.

Schuele WJ. Preparation of fine particles from bi-metal oxalates. J Phys Chem. 1959;63:83-6.

Gao X, Chen D, Dollimore D, Jankun ES, Burckel P. Identification of solid solutions of coprecipitated Ni-Co

oxalates using XRD,TG and SEM techniques. Thermochim Acta, 1993; 22:75-89.

Gallagher PK. Application of thermal analysis to the study of inorganic materials. Thermochim Acta. 1993;214:1-7.

Donia M, Dollimore D. Preparation, identification and thermal investigation of solid solutions of cobalt-copper

oxalates. Thermochim Acta. 1997;290:139-47.

Yuan C, Wu HB, Xie Y, Lou XW. Mixed transition-metal oxides: design, synthesis, and energy-related applications.

Angew. Chem. Int. Ed. 2014;53:1488 – 504.

Vyazovkin S. Computational aspects of kinetic analysis, Part C. The ICTAC Kinetics Project - the light at the end of

the tunnel?. Thermochim Acta. 2000;355:155-63.

Vyazovkin S, Sbirrazzuoli N. Isoconversional analysis of the non-isothermal crystallization of a polymer melt.

Macromol Rapid Comm. 2002;23:766-70.

Vyazovkin S, Sbirrazzuoli N. Estimating the activation energy for non-isothermal crystallization of polymer melts. J

Therm Anal Calorim. 2003;72:681-6.

Joraid AA, Abu-Sehly AA, El-Oyoun MA, Alamri SN. Non-isothermal crystallization kinetics of amorphous

Te51.3As45.7Cu3. Thermochim Acta. 2008;470:98-104.

Starink MJ. The determination of activation energy from linear heating rate experiments: a comparison of the

accuracy of isoconversion methods. Thermochim Acta. 2003;404:163-76.

Vyazovkin S, Sbirrazzuoli N. Isoconversional approach to evaluating the hoffman-lauritzen parameters (U* and Kg)

from the overall rates of non-isothermal crystallization. Macromol Rapid Comm. 2004;25:733-8.

Khawam A, Flanagan DR. Role of isoconversional methods in varying activation energies of solid-state kinetics: II.

Non-isothermal kinetic studies. Thermochim Acta. 2005;436:101-12.

Vyazovkin S. Model-free kinetics, staying free of multiplying entities without necessity. J Therm Anal Calorim.

;83:45-51.

Vyazovkin S, Sbirrazzuoli N. Isoconversional kinetic analysis of thermally stimulated processes in polymers.

Macromol Rapid Comm. 2006;27:1515-32.

Starink MJ. Activation energy determination for linear heating experiments: deviations due to the low temperature end

of the temperature integral. J Mater Sci. 2007;42:483-9.

Muraleedharan K, Kripa S. DSC kinetics of the thermal decomposition of copper(II) oxalate by isoconversional and

maximum rate (peak) methods. J Therm Anal Calorim. 2014;115:1969-78.

Muraleedharan K, Mallikassery JJ, Sarada K, Kannan MP. Isothermal decomposition of K2C2O4. J Therm Anal

Calorim. 2014;116:1055-60.32. Vyazovkin S, Wight CA. Isothermal and non-isothermal kinetics of thermally

stimulated reactions of solids. Int Rev Phys Chem. 1998;17:407-33.

Bonnet E, White RL. Species –specific isoconversion effective activation energies derived by thermogravimetry-mass

spectrometry. Thermochim Acta. 1998;311:81-6.

Flynn JH, Wall LA. Direct method for the determination of activation energy from thermogravimetric data. Polym

Lett. 1966;4:323-8.

Ozawa T. A new method of analyzing thermogravimetric data. Bull Chem Soc Jpn. 1965;38:1881-2.

Kissinger HF. Reaction kinetics in differential thermal analysis. Anal Chem. 1957;29:1702-6.

Tang W, Liu Y, Zhangand CH, Wang C. New approximate formula for arrhenius temperature integral. Thermochim

Acta. 2003;408;39-43.

Vyazovkin S. Modification of the integral isoconversional method to account for variation in the activation energy. J

Comput Chem. 2001;22:178-83.

Vyazovkin S, Dollimore D. Linear and nonlinear procedures in isoconversional computations of the activation energy

of nonisothermal reactions in solids. J Chem Inf Comp Sci. 1996;36:42-5.

Vyazovkin S, Evaluation of activation energy of thermally stimulated solid-state reactions under arbitrary variation of

temperature. J Comput Chem. 1997;18:393-402.

Vyazovkin S, Burnham AK, Criado JM, Pérez-Maqueda LA, Popescu C, Sbirrazzuoli N. ICTAC Kinetics committee

recommendations for performing kinetic computations on thermal analysis data-Review. Thermochim Acta.

;520:1–19.

Vyazovkin S. Thermal analysis. Anal Chem. 2002;74:2749–62.

Mujeeb VMA, Muraleedharan K, Kannan MP, Devi TG. The effect of particle size on the thermal decomposition

kinetics of potassium bromate: An isothermal thermogravimetric study. J Therm Anal Calorim. 2012;108:1171–82.

Lamprecht E, Watkins GM, Brown ME. The thermal decomposition of copper(II) oxalate revisited. Thermochim

Acta. 2006;446:91-100.

Patterson AL. The Scherrer formula for X-Ray particle size determination. Phys Rev. 1939;56:978-82.

Nakamoto K, Fujita J, Tanaka C, Kobayashi M. Infrared spectra of metallic complexes. IV. Comparison of the

infrared spectra of unidentate and bidentate metallic complexes. J Am Chem Soc. 1957;79:4904-8.

Rao CNR. Chemical applications of infra red spectroscopy. New York:Academic Press. 1963;365-7.

Schmelz MJ, Miyazawa T, Mizushima S, Lane TJ, Quagliano JV. Infra red absorption spectra of inorganic co-

ordination complexes – IX Infra red spectra of oxalate complexes. Spectrochim Acta. 1957;9:51-8.

Fujita J, Nakamoto K, Kobayashi M. Infrared spectra of inorganic and co-ordination Compounds. J Phys Chem.

;61:1014-5.


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