In ~10-5 M acidic aqueous solutions of Methyl Orange the rate constant at 25°for the recombination of a proton with the monoanion of the indicator is 2.9 ± 0.4 x 109 M-1 sec-1. This specific rate, determined by a spectrophotometric electric field jump relaxation technique, is significantly smaller than that expected for a diffusion-controlled ion recombination. An explanation for this result follows from a comparison with similar kinetic data for aqueous Methyl Red.

Figure 2. Expanded graph of activity of water at low THF concentrations occurred in the melting point of the hydrate (4, 10), the viscosity (9), and the freezing rate (8) of the solutions. However, the accuracy of the data is not sufficient to make any definitive statement about this phenomena.

The kinetics and energetics of the dimerization of 4,4',4",4"'-tetrakisoctadecylsulphonamidocopper(II) phthalocyanine (CuPC) dye in benzene is reported. A negative activation energy of -62.27 kJ mol-l for the generalized dimerization process (i) indicates a multi-step reaction mechanism. Results are interpreted in the light of previously kr CUPC + CUPC * (CUPC), (0 kr reported calorimetric data and as a multi-step reaction. Additionally, the kinetics of dimerization of the CuPC dye in carbon tetrachloride at 25 "C are reported with the apparent forward rate constant (k,) being 3.6 (k0.4) x l o 7 I mols-and the reverse rate constant (k,) being 30 (*3) sl.

No abstract

The thermodynamics of dimerization of 4,4',4",4"'tetraoctadecylsulfonamido copper(ll) phthalocyanine were determined at 35°C in benzene solvent by an adiabatic calorimetric technique. Data were interpreted by two methods, each of which yielded the same values. The values for the thermodynamics of dimerization in benzene at 35°C were:°= "12 ± 1 kcal/mol, AGd°= -5.6 ± 0.8 kcal/mol, and ASd°= -21 ± 3 cal/deg mol. A value for ÁCp°for the range 25-35°C was calculated to be -200 ±100 cal/deg mol.