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The mechanism of the decomposition of monoperoxyphthalic acid has been investigated. The rate law is analogous to those found for other monosubstituted peroxides (second order in peroxide with a maximum rate at pH equal to pK* of peroxidic proton). The isotope data are consistent with previously observed cases in that the data are explicable in terms of two competing transition states of identical composition but different configuration.

Equations were developed to describe the experimental rates of formation of ethylene oxide hydrate from stirred, incongruent solutions. Heat conduction through the walls of the dilatometer bulb was rate-controlling. Results for congruent solutions were consistent with these equations during the early stages of hydrate growth.Canadian Journal of Chemistry, 46, 3867 (1968) General observationsIn Part I the kinetics of hydrate formation from congruent solutions were described. Experiments on incongruent solutions using the magnetically stirred dilatometer were conducted (a) in the water-rich region on solutions containing 5.62 mole % ethylene oxide (EO) which forms a hydrate of formula E0.7.05 H 2 0 at freezing point TfO = 8.02 "C, and (b) in EO-rich solutions containing 34.03 mole % EO which forms a hydrate of formula identical to that in congruent solutions, E0.6.89 H 2 0 , at freezing point TfO = 8.04 "C (1, 2). The tabulated results are given in Part I112.The behavior of EO hydrate formation from stirred incongruent solutions was entirely different from that in congruent solutions. The crystals appeared as small spheres (3), up to about 1 mm in diameter, and did not stick to the glass walls, so that all experiments on incongruent solutions were made in the magnetically stirred dilatometer. Hydrate formation decreased steadily with time and eventually ceased altogether as shown by the results in Fig. 1 for the water-rich region (a). Correspondingly, the solution temperature rose rapidly to a sharp maximum, then decreased back to the thermostat temperature. WMA stands for water-rich, magnetically stirred solution, EMA stands for EO-rich, magnetically stirred solution, and SUM stands for summary of results.At constant thermostat temperature, the rates of hydrate formation are practically identical at stirring rates of 100 r.p.m. or greater, as shown in Fig. 1 by the identical hydrate formation rate curves for run WMA42 at 100 r.p.m. and WMA5 at 320 r.p.m. Dependence of hydrate formation rate onResults in water-rich solutions revealed that, after the maximum temperature increase, there was a direct proportionality between the rate of hydrate formation and the difference of the solution and thermostat temperatures, (To,, -T,): the data are plotted accordingly in Fig. 3 This dependence is consistent with the rate of hydrate formation depending on the rate of heat conduction through the glass walls of the dilatometer bulb. Accordingly, we derive an expression for this process and compare our experimental results with this expression. Assume the simplest possible temperature profile through the wall as follows: For personal use only.

Kinetic studies of the iron-salt-catalyzed decomposition of hydrogen peroxide in H202+ H20 mixtures have suggested the importance of ferric-peroxy complexes as intermediates in the reaction. In this paper, spectrophotometric evidence for the existence of complexes of the type proposed is described. Measurements of the kinetics of chromium(V1)-salt catalysis of the decomposition of hydrogen peroxide in H202-t.H20 mixturesare also reported. The results are shown to be consistent with the model proposed for iron-salt catalysis. The implication that the iron and chromium catalyses proceed by a similar mechanism is discussed and the analogy between the proposed model and an enzyme reaction is pointed out.

A dilatometer was constructed for studying the formation of ethylene oxide hydrate. In unstirred, congruent solutions heat transfer appeared to be the significant rate-controlling factor. Initial hydrate formation rates were independent of stirring at speeds greater than approximately 100 r.p.m. Magnetic stirring was inadequate due to hydrate build-up on the walls of the dilatorneter bulb. Mechanical stirring eliminated this build-up and gave satisfactory results.