摘要:

The kinetics of the thermal insertion of SnCl2and SnBr2into the metal–metal bond of [π-C5H5NiCO]2have been studied. On the basis of the kinetic data a bimolecular mechanism, involving direct attack of the tin(II) halide on the nickel dimer, has been proposed. The thermal insertion with tin(II) bromide was found to proceed with an activation enthalpy of 19.4 ± 0.2 kcal/mol and an activation entropy of −8.8 ± 0.4 cal deg−1 mol−1. For the thermal insertion with tin(II) chloride a ΔH≠and ΔS≠of 22.5 ± 0.2 kcal/mol and −4.0 ± 0.2 cal deg−1 mol−1, respectively, were observed.

ISSN:0008-4042    

DOI:10.1139/v71-436

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Viscosities are reported at 25 °C in five 1-chloroalkane binary systems. Mixture data are presented both as kinematic viscosity and as excess Gibbs free energy of activation for flow. The latter quantity is correlated with the average chain length in the mixtures by graphical and analytical forms of Brønsted and Koefoed's principle of congruence. This correlation serves as a basis for prediction of mixture viscosities for 1-chloroalkane pairs having chain lengths within the observed extremes: 1-chlorobutane and 1-chlorooctadecane. Errors as kinematic viscosity by this method are less than 5.5% for the systems studied.

ISSN:0008-4042    

DOI:10.1139/v71-437

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Thermal pressure and energy–volume coefficients have been determined for various methyl alcohol – water andt-butyl alcohol – water mixtures at several temperatures in the range 19–55 °C. The energy–volume coefficient is found to pass through a maximum at 0.3–0.4 mole fraction methyl alcohol and 0.1 mole fractiont-butyl alcohol. This behavior is consistent with the average intermolecular distance passing through a minimum in both systems at the corresponding solvent compositions. The relationship between the energy–volume coefficient, the cohesive energy density, and the structure of aqueous binary systems is examined. The temperature dependence of the thermal pressure coefficient is discussed in terms of the effect of temperature on the susceptibility of the entropy of the two systems to isothermal expansion.

ISSN:0008-4042    

DOI:10.1139/v71-438

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

The form of the spacial distribution function of ions and electrons in an irradiated liquid is not accurately known and several types of function have been assumed by different workers. The various forms are compared and used in the calculation of electron–solute reaction yields in liquid cyclohexane. Our previously used semi-empirical distribution function (YSE) and a power function (YP) give satisfactory I results, but a three dimensional, single parameter Gaussian (YG1) and a delta function (YD) do not. The prescribed diffusion approximation has also been inserted into the model for comparison with earlier work. No improvement was obtained. Whereas our previous approximations may lead to an underestimate of the geminate neutralization times, the prescribed diffusion approximation may lead to an overestimate of them.

ISSN:0008-4042    

DOI:10.1139/v71-439

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

The yield of hydrogen from pure hexane,G(H2) = 5.3 ± 0.2 was independent of pressure in the range 1 bar to 4.6 kbars. TheGvalues of H2, HD, and D2obtained from 11 mol% C6D14in C6H14were independent of pressure and were respectively, 4.85, 0.34, and 0.11. The electron and hydrogen atom scavenging efficiencies of carbon tetrachloride and hexadiene-1,3, and the hydrogen atom scavenging efficiency of hexene-1 were independent of pressure. The positive ion scavenging efficiencies of benzene and aniline increased with increasing pressure. The volume of activation for the hydrogen atom reaction withn-hexane is essentially the same as that for the reaction with hexene-1. The pressure dependence of the charge scavenging reactions has been interpreted in terms of the kinetics of spur processes. The treatment is consistent with the fact that the efficiency of the electron scavenging reactions is independent of pressure. The increased efficiency of positive ion reaction under pressure implies that the ratio of the diffusion coefficients of the radiolytic positive ion and electron,D+/D−, increases with increasing pressure.

ISSN:0008-4042    

DOI:10.1139/v71-440

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

The electroreduction of periodate anion was studied at a dropping mercury electrode in aqueous solutions in the pHrange 11–13.3 where the process is markedly affected by the double layer. The electrode reaction was found to be complex, its mechanism depending on both pHand ionic strength. The effects of the double layer on the component reactions are discussed with respect to current theoretical developments.

ISSN:0008-4042    

DOI:10.1139/v71-441

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Metallic silver initiates short-chain homolytic decomposition of tertiary alkyl hypochlorites and hypobromites. Evidence is presented that the reaction of tertiary alcohols with silver oxide – mercuric oxide – bromine involves formation and homolytic decomposition of alkyl hypobromite followed by cyclization of γ-bromo alcohols. A convenient synthesis of tricyclo[4.3.1.03,8]decan-4-one (4-proto-adamantanone) is described.

ISSN:0008-4042    

DOI:10.1139/v71-442

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

The configuration and conformation of the two isomeric methyl enol ethers of acetylacetone (1) have been unequivocally demonstrated. The n.m.r. solvent shift data and observation of nuclear Overhauser effects support an s-cisconformation for the more stable isomer2bearing acetyltransto methoxyl while indicating an s-transconformation for the less stable enol ether3having acetylcisto methoxyl. The facile acid-catalyzed isomerization of3to2apparently proceeds by reversible protonation of carbonyl oxygen since no deuterium incorporation is observed when the isomerization is performed in acetic acid-d4.

ISSN:0008-4042    

DOI:10.1139/v71-443

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

On treatment of cardenolides with ammonia or methylamine two isomers are obtained, 21-amino-14β,21-oxidonorcholan-23-oic acid lactam and 21-amino-14β-hydroxy-16β,21-oxidonorcholan-23-oic acid lactam. The assignment of stereochemistry to each isomer is based on the n.m.r. spectra and the correlation with the structure of isodigitoxigenin or isogitoxigenin.

ISSN:0008-4042    

DOI:10.1139/v71-444

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

The electrolysis of α-chlorovaleric, α-chlorocaproic, and α-chloroisobutyric acids in methanol gave none of the Kolbe dimer; the main products were chloroester and hydrogen ester with aldehydes and acetals formed in lesser amounts. In water, straight chain α-chloroacids gave dimeric esters as the major product. However, Kolbe dimer was formed in fairly good yields together with small amounts of fluoroester and acetal, when α-fluorocaproic and α-fluoroheptanoic acids were electrolyzed in methanol. No Kolbe dimer was produced from 2-fluoro-2-ethylbutanoic and α-fluorophenylacetic acids; the corresponding ketone or aldehyde was the major product.

ISSN:0008-4042    

DOI:10.1139/v71-445

出版商:NRC Research Press    

年代:1971

数据来源: NRC