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Analysis of eq 6 reveals an extremely sensitive dependence of K0 on d. For instance, the ionic radius of Cs+ (r s 1.7 X 10~8 cm) is larger than that of K *(rs 1.3 X 10'8 cm) by about 0.4 Á. If d is increased from 2 X 10'8 to 2.4 X 10"8 cm, the value of K0 decreases from 3 X 101 234 to 681 M'1 by keeping e = e00 = 4.1. This substantial change in K0 would only partially account for the reported2 K values ranging from 11•14 M'1 for K+ cryptate down to 1041 M'1 for Cs+ cryptate.Mei et al.10 studied the variation of the 133Cs chemical shift of the Cs+ cryptate as a function of temperature in propylene carbonate solvent. Comparison with similar data obtained in dimethylformamide and acetone indicates that the chemical shift is no longer solvent dependent at low temperatures, where an inclusive complex predominates. At high temperatures the cation is only partially accommodated inside the cryptand cavity and is thus only partially insulated from solvent effects. For the scheme Cs+ + C222 «=t the values AH°i2 = -8.6 ± 0.4 kcal mol'1 and °12 = -13.7 ±

A model for the ferroin-bromate-bromide-sulfuric acid system in a continuously stirred (flow-through) tank reactor has been constructed by extending the Noyes-Field-Thompson mechanism with the following composite processes: (a) ferroin-bromate, (b) ferroin-bromous acid, (c) ferroin-hypobromous acid, (d) ferroin-bromine, (e) ferriin-bromide, and (f) ferriin-bromine. The calculated high-amplitude oscillations and kinetic phase diagram are in good accordance with the experiments reported earlier. By completing the scheme with a reaction step accounting for the precipitation and dissolution of a ferroin-tribromide salt. the batch oscillations found at high concentrations of reactants can also be simulated. IntroductionThe Belousov-Zhabotinsky (BZ) oscillatory reaction, the cerium(II1)-catalyzed oxidation of malonic acid by acidic bromate, has been commonly applied during the last few decades for studying a wide variety of temporal and spatial instabilities in chemical

A multiparameter artificial neural network (ANN) approach was successfully utilized to predict the solubility of C60 in different solvents. Molar volume, polarizability parameter, LUMO energy, saturated surface, and average polarizability molecular properties were chosen to be the most important factors determining the solubilities. The results show that in a large number of solvents (126) the solubility decreases with increasing molar volumes of the solvents and increases with their polarizability and saturated surface areas. A method is suggested to the approximate determination of experimentally not easily measurable solubility related thermodynamic parameters, e.g., the Hildebrand parameter, based on reliable solubility measurements.