摘要:

The 220 MHz n.m.r. spectrum ofN-nitrosocamphidine is interpreted in terms of a 1:1syn-antiisomer mixture. Benzene solvent-induced shifts and the spectrum of the tris(dipivalomethanato)europium(III) – nitrosocamphidine complex are used to assign the methyl resonances.

ISSN:0008-4042    

DOI:10.1139/v71-388

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Under γ-irradiation, aqueous solutions of ethylene glycol containing hydrogen peroxide form acetaldehyde as a major product via a free-radical chain rearrangement. The yield of acetaldehyde is essentially unchanged when hydrogen peroxide is replaced by N2O or HClO4. A mechanism is proposed in which the glycol radical, ĊOHCH2OH, rearranges to the acetaldehyde precursor, ĊH2CHO, followed by the hydrogen atom transfer reaction;thus propagating a chain reaction.2The rearrangement is also induced by the photo-dissociation of H2O2in aqueous solutions of ethylene glyco

ISSN:0008-4042    

DOI:10.1139/v71-389

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

The kinetics of the reaction oftrans-[PtCl2py2] with a series of 4,4′-disubstituted diphenyl sulfides, XC6H4SC6H4Y, have been studied at 30° in methanol. A linear free energy correlation has been obtained between the logarithm of the second order rate constant and the sum of the Hammett substituent parameters for X and Y. This result is consistent with the notion that bond making is the driving force when divalent sulfur functions as a nucleophile towards platinum(II) substrates and is consistent with the inability of 4,4′-dinitrodiphenyl sulfide to coordinate to platinum(II).

ISSN:0008-4042    

DOI:10.1139/v71-390

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

The pseudo first order rate constants for the solvolysis of benzyl chloride in aqueoust-butyl alcohol (t-BuOH) are reported at 40.00, 50.25, and 60.50 °C at various pressures up to 4084 atm. From these data the first temperature derivatives (ΔH* and ΔS*), the first (ΔV*) and second pressure derivatives, ∂ΔV*/∂P, and the mixed second derivative, ∂ΔV0*/∂T, of the rate are evaluated. These activation parameters exhibit extremum behavior in the highly aqueous solvent region. This behavior is discussed in terms of solvent structure variation. The signs of the pressure dependence of ΔH* and ΔS* are shown to be consistent with those required by the Maxwell type relationships for classical thermodynamic systems.

ISSN:0008-4042    

DOI:10.1139/v71-391

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Radiochemical and electrochemical evidence is presented that electrochemically generated tritium and hydrogen atoms permeate through lead foil at measureable rates at room temperature. The permeation process is controlled by diffusion through the metal lattice, Fick's First Law being obeyed by both H and3H atoms. Using earlier measurements of the diffusivity of H in Pb, H and3H concentrations of 4 × 10−7and 9 × 10−13 g-atom cm−3are computed for a current density of 53 mA cm−2at the Pb cathode surface.The overall hydrogen-tritium separation factor,STis apparently 0.3 ± 0.15, in contrast to Bockris and Srinivasan's 6.7 and 7.2 for cathodic gas evolution from acidic and alkaline media, respectively. Reasons are suggested for this large difference.

ISSN:0008-4042    

DOI:10.1139/v71-392

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

A systematic survey of the kinetic characteristics of the intramolecular cation exchange reactions of semiquinone ion-pairs is described. A linear correlation exists between the free energy of activation for the exchange and the strength of the ionic interaction within the ion pair; however, this correlation does not extend to the enthalpy of activation. The significance of the kinetic parameters is discussed in terms of the role solvation plays in determining the course of the exchange process.

ISSN:0008-4042    

DOI:10.1139/v71-393

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

The anodic oxidation of cholesterol yields 3β,3′β-(methylenedioxy)-dicholest-5-ene. A new method for the preparation of methoxymethyl ethers of steroids is described. The n.m.r. and mass spectra of these compounds is reported.

ISSN:0008-4042    

DOI:10.1139/v71-394

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

The synthesis of some potential nitrogen mustard precursor 17α-bis(2-hydroxyethyl)aminomethyl androst-17β-ol derivatives has been achieved by two routes. During the investigation, unequivocal proof was obtained that addition of cyanide to 17-keto steroids gives predominantly 17β-hydroxy-17α-cyano epimers.

ISSN:0008-4042    

DOI:10.1139/v71-395

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

3-n-Alkylpyrroles are prepared in good yield by a combined Wolff-Kishner reduction and hydrolysis and decarboxylation of 4-acyl-2-pyrrolethiolcarboxylates. Methyl 4-isopropyl-2-pyrrolecarboxylate and 4-t-butyl-2-pyrrolecarbonitrile are prepared by alkylation of methyl 2-pyrrolecarboxylate and 2-pyrrolecarbonitrile respectively. Hydrolysis and decarboxylation of these disubstituted compounds afford the corresponding 3-alkylpyrroles. Mass spectral data for some 1-, 2-, and 3-alkylpyrroles are reported.

ISSN:0008-4042    

DOI:10.1139/v71-396

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

The hydrothermal deposition of CrO(OH) from aqueous chromium(III) chloride, nitrate, and perchlorate, and of Cr3(SO4)2(OH)5•H2O and Cr(OH)SO4•2H2O(?) from aqueous chromium(III) sulfate, has been investigated. Aqueous chromium(III) is oxidized to chromium(VI) by 0.4 Mperchloric acid above 225 °C, and by molecular oxygen above 250 °C. Aqueous chromium(III) can react at 300 °C with iron or steel, cobalt, and copper to produce FeCr2O4, CoCr2O4, and Cu2Cr2O4, respectively. CrO(OH) reacts with type 316 stainless steel at 440 °C in supercritical water of density 0.7 g cm−3to yield (Fe,Ni)-Cr2O4, which is the "cubic Cr2O3" of Laubengayer and McCune. The spinels MCr2O4(M = Mg, Mn, Fe, Co) can be made hydrothermally atca. 300 °C from Cr(OH)3and M(OH)2. This information is relevant to corrosion phenomena, and the possible hydrothermal origin of chromite deposits in serpentinized rocks.

ISSN:0008-4042    

DOI:10.1139/v71-397

出版商:NRC Research Press    

年代:1971

数据来源: NRC