The effect of temperature on the dynamics of a homogeneous oscillatory system operated in batch and under flow

Author(s)

Nogueira, Paulo A. ^[1] ; Batista, Bruno C. ^[1] ; Faria, Roberto B. ^[2] ; Varela, Hamilton ^{[1, 3]}

Affiliation

^[1] Univ Sao Paulo, Inst Chem Sao Carlos, BR-13560970 Sao Carlos, SP - Brazil

^[2] Univ Fed Rio de Janeiro, Inst Quim, BR-21941909 Rio De Janeiro, RJ - Brazil

^[3] Fritz Haber Inst, Max Planck Soc, D-14195 Berlin - Germany

• Document type: Journal article
• Source: RSC ADVANCES; v. 4, n. 57, p. 30412-30421, 2014.
• Web of Science Citations: 1

Abstract

The effect of temperature on a network of chemical reactions is not obvious, especially when compared to the effect exerted on elementary steps. There are few reports regarding the estimation of parameters such as activation energies for oscillating chemical systems. Still less investigated is the importance of the relative distance from thermodynamic equilibrium on the way in which temperature influences the oscillators' dynamics - a crucial aspect for the understanding of chemical and bio-chemical oscillating networks. In this paper we use the bromate-oxalic acid-acetone-cerium oscillatory system to study the influence of temperature under close and far-from-equilibrium regimes. The research was carried out under identical conditions for batch and flow (in a continuous flow stirred tank reactor, CSTR) regimes, and the main oscillation features were preserved, so that it was possible to isolate the effect of flow. Overall, increasing the flow results in an increase of the oscillatory frequency. The apparent oscillatory activation energy was found to decrease from 72 +/- 6 kJ mol(-1), for the system operated in batch, to 50 +/- 2 kJ mol(-1), under the flow regime. The role of the distance from the thermodynamic equilibrium on the temperature dependence is generalized and discussed in connection with other systems. Numerical simulations using the Brusselator model under batch and flow regimes further helped the discussion of the main experimental results. (AU)

• FAPESP's process: 12/24152-1 - Complex kinetics in electrochemical systems: mechanisms, stoichiometric network analysis and numerical simulations
• Grantee: Hamilton Brandão Varela de Albuquerque
• Support Opportunities: Scholarships abroad - Research
• FAPESP's process: 09/07629-6 - Electrocatalysis IV: fundamental and applied aspects of electrocatalytic processes, bio-electrocatalysis and kinetic instabilities
• Grantee: Edson Antonio Ticianelli
• Support Opportunities: Program for Research on Bioenergy (BIOEN) - Thematic Grants