These comparisons suggest that the low value of k2"/k, for reaction of pNPDPP with OHis caused by a relatively deeper penetration of this substrate into the micelle as compared with that of DNCB. A similar conclusion has been made for reactions in functional micelles.53 Values of kz"/kw for reactions of DNCB with phenoxide ion and pNPDPP with aryloxide and oximate ions are close to ~n i t y , 3~~p~~v~~ probably because the hydrophobicities of substrates and nucleophiles are such that both reside in the same region of the micelle.% Similar conclusions have (53) Bunton, C. A. in ref 32, Vol. 2, p 519. Bunton, C. A.; Sepulveda, L. Isr. J. Chern. 1979, 18, 298. (54) The second-order rate constants for reactions of several nonionic nucleophiles in the micellar pseudophase are smaller than in but these rate differences are understandable in terms of the lower polarity of the Stern layer as compared with water.Sb,S6
Partly Cu(II) ion-exchanged Y zeolite (Cu(II)NaY) catalyzes the NO-NH3 reaction at lower temperatures, but with rising temperature its activity decreases after a maximum at 120 °C. ESR spectra showed that the catalytic activity correlated intimately with the oxidation state of Cu ions. A catalytic reaction path consisting of three steps was proposed based on kinetic and 15N tracer studies.Step I is a Langmuir-Hinshelwood type of bimolecular reaction between NO and NH3 on Cu(II), which produces Cu(I) and H+ in addition to N2 and H20.Step II is a NO disproportionation reaction (3NO -* N20 + N02) catalyzed by ammine complex of Cu(I), the produced N02 oxidizing Cu(I) to Cu(II).Step III is a complementary step to consume the H+ and N02" formed above. The IR study for step II revealed the formation of two types of N02 intermediates, i.e., a nitrito type (Cu-ONO) and a nitrite ion type (N02"), of which the former type was shown to be a precursor of the latter.
Reactivities of six allylic chlorides with benzene and toluene were studied in the substitution reaction catalyzed by tungsten hexachloride. Alkylation at the allylic position takes place in the first step. Hydrogen chloride consecutively adds to the double bond of the substituted group. The reactivities of allylic chlorides in the allylation and hydrochlorination are discussed relative to the structure of the assumed intermediate. Toluene is more reactive than benzene in the competitive reaction but less reactive in the single reaction. Relative reactivities are explained in terms of an equilibrium step of complex formation between tungsten hexachloride and the aromatic hydrocarbon before the rate-determining step, where the cationic allyl species may react with the benzene ring.
OH‐Gruppen stellen die Hauptspezies des an S1102 adsorbierten Wassers dar, während der Anteil an über H‐Bindungen an O2 ′‐Ionen gebundenen molekularen Spezies beträchtlich geringer ist.
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