A. Komlosi et al., CONVECTIVE CHEMICAL FRONTS IN THE 1,4-CYCLOHEXANEDIONE-BROMATE-SULFURIC ACID-FERROIN SYSTEM, The journal of physical chemistry. A, Molecules, spectroscopy, kinetics, environment, & general theory, 102(46), 1998, pp. 9136-9141
Traveling waves were investigated in the Belousov-Zhabotinsky reaction
in which 1,4-cyclohexanedione was the substrate. Isothermal density c
hange (Delta rho(c)) and reaction enthalpy were determined. Delta rho(
c) is positive, while the reaction enthalpy is negative; therefore, do
uble-diffusive convection was expected according to the Pojman-Epstein
model. Experiments were carried out in tubes and in spectrophotometri
c cells. In tubes the effect of the diameter and the orientation of th
e tube on the wave velocity and on the wave shape was studied; gravita
tional anisotropy and the expected double-diffusive convection were fo
und. Experiments in cells were compared to the calculations of Wu et a
l. (Wu, Y.; Vasquez, D. A.; Edwards, B. F.; Wilder, J. W. Phys. Rev. E
1995, 51, 1119-1127). They predicted a critical cell width under whic
h no simple convection should occur. However, because double-diffusive
convection was observed, their calculations are not directly applicab
le.