|Budget Amount *help
¥4,600,000 (Direct Cost: ¥4,600,000)
Fiscal Year 1997: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1996: ¥4,100,000 (Direct Cost: ¥4,100,000)
1.Viscosity measurements. Viscosity of 2,4-dicyclohexy1-2-methylpentane was measured at conditions of 25-150ﾟC and 0.1-430 MPa.
2.Measurements on a compound with a smaller degree of freedom of motion. Viscosity dependence of the Z/E isomerization of N,N'-dimethylindigo (DMIG) was measured in glycerol triacetate. The viscosity dependence was found to be comparable with those of other compounds with a larger degree of freedom of motion. The reaction deviated from the first-order rate law at high viscosities.
3.Measurements on a compound with a positive electrical charge. Viscosity dependence of the Z/E isomerization of 3,3'-diethyloxacarbocyanine iodide was measured in 2-methyl-2,4-pentanediol (MPD). Despite the existence of a positive charge, the viscosity dependence was similar to the ones observed for neutral compounds.
4.Measurements on a reaction with charge neutralization. Disappearance of a merocyanine formed from 1,3-dihydro-1,3,3-trimethylspiro [2H-indole-2,3'- [3H] naphth [2,1-b] [1,4] oxazine was kinetically studied in MPD at high pressures. Retarding viscosity effect was evident at much lower viscosities than other reactions.
Theoretical considerations. (1) A prediction by Biswas and Bagchi, i.e., isomerization rate will be inversely proportional to a logarithm of the solvent viscosity at high viscosities, was not supported by our results and it was concluded that the one-dimensional reaction coordinate model cannot describe our reaction systems. (2) It is deduced that the photo-produced (Z) -DMIG molecules do not obey Boltzmann distribution and, therefore, the reaction becomes multi-exponential. (3) In order to clarify the reason for the appearance of the viscosity effect at much lower values in the last reaction, further accumulations of experimental results are required.