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Kinetic measurements and product identifications have been carried out in order to elucidate the mechanisms of several more imine ring openings. Aziridines studied were 2,2-dimethylethylenimine, 2-ethylethvlenimine, N-(ra-butyl)-ethvlenimine and ethylenimine; nucleophiles studied were acetate, bromide, chloride, iodide, thiocyanate and thiosulfate ions, thiourea and water. Hydrolysis rates were studied over a range of temperature and pressure so as to obtain activation parameters.All of the reactions studied have been found to correlate with known mechanistic patterns. The use of linear free energy equations for the evaluation of relative contributions of Sxl and Sn2 behavior in solvolysis reactions is pointed out.

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Hydrolysis of 2,2-dimethylethylenimine in hydrochloric acid gave l-chloro-2-atni1~o-2-methylpropane (11) and l-arnino-2-methyl-2-propanol ( I V ) in varying ratios depending on the temperature, concentration of acid and imine t o acid ratio. In the special case of hydrolysis of 2,2-dimethylethylenimine picrate, water done gave 954.t of amino alcohol (IVI and 12 A' hydrochloric acid gave 747, of chloroamine I1 and 125; of 2-chloro-l-amino-2-niethylpropane (111) The results are interpreted as due to competing Ssl and S N 2 processes and this is supported by the nature of the products and kinetic data.

Ammonia and amines1 in aqueous solution react with imines to give a, /3-diamines and polymeric substances. The reaction between ethylenimine and various amines to give N-substituted ethyl-

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The Preparation and Properties of Cobalt Coórdination Compounds 171 condition in which essentially all sulfate ions are combined in a complex such as CeSC>4++. If, however, the cerium(IV) concentration is constant and the sulfate is increased, there is not any such constant value for D since additional ceriumsulfate linkages may be formed as other sulfate ions become included in the complex._ It may be noted that the experimental curve of D versus sulfate does not level off at ordinary concentrations.It may be concluded, therefore, that the complex ion made up of one cerium(IV) and one sulfate ion predominates in solutions less than 0.01 M in concentration, with other complex ions being formed at higher concentrations.Jones and Soper reported a "slight migration of color" toward the anode in transference experiments and concluded a complex anion must exist. This is also in accord with the results above, since these data indicate that in more concentrated solutions complex anions such as Ce(S04)8" may be present.Instability Constant.-By assuming that the flat portion of the curve in Fig. 6 represented complete combination of sulfate to form complex ions, the extinction coefficient of this complex was calculated from the observed value of D and the known concentration of sulfate. With this extinction coefficient and the values of D observed for various points on the curves of Fig. 4, equilibrium concentrations of the complex ion, cerium(IV) ion, and sulfate ion were calculated. From these, the instability constant (K) of the ion was calculated. The extent of ionization for the conditions of Fig. 6 was then calculated and corrections made in the extinction coefficient, the equilibrium concentrations and in the values of K. These corrections gave an average value of 4.3 X 10~4 for K in solutions having total cerium(IV) + sulfate concentrations equal to 0.00493 M.The extinction coefficient could also be used to calculate equilibrium concentrations for the points on curves such as those of Fig. 3. From these data, average values of K equal to 4.7 X 10-4 and 5.3 X 10-4 were obtained for solutions 0.0043 M and 0.0020 M, respectively, in total cerium(IV).By ftirther approximations in the extinction coefficient, somewhat better agreement in values for K might be obtained, but, because of the lack of temperature control, etc., the results would probably not be significant.The methods used here did not supply any evidence as to the presence of H+ or OHions in the complex. With such high acid concentrations, a complex ion containing OHis unlikely, but it is quite possible that hydrogen ion may be combined with the cerium(IV) and sulfate.Experiments are now being carried out in these laboratories to determine whether these results will permit calculations of the influence of sulfate on the rates of reaction of cerium(IV) solutions and to determine the influence of ions such as chloride and nitrate upon the cerium(IV) sulfate complex. Summary 1. Spectrophotometric studies of cerium(IV) perchlorate solutions showed no evidence o...

The fragmentation patterns of seven oxadiazolines (compounds I‐VII) were obtained from mass spectral data. Fragmentations a and b (Figure 1) are more important than c. Some of the novel cracking pathways are discussed.