摘要:

Total deactivation rate constants have been determined for N2+(B2Σu+) and the (A2Πu) and (B2Σu+) states of CO2+with a number of quenchers. The energy specific total deactivation rate constant is compared to the total radiative lifetime of the excited species. A particular novelty of the technique is that it does not require a complete knowledge of the formation modes for the excited species. The results are compared with theoretical values obtained from the ion-induced dipole model. Individual deactivation rate constants are presented for N2+(B2Σu+) ions in thev = 0, 1, and 2 vibrational levels quenched by N2, O2, H2, and CO2; and for the(A2Πu) and (B2Σu+) states of CO2+quenched byCO2, N2, O2, NO, and H2. Charge transfer is the most probable mode of deactivation except in the CO2+–H2reactions where H-atom abstraction is more probable.

ISSN:0008-4042    

DOI:10.1139/v72-001

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Pure samples2of Re(hfac)3and Re(acac)3have been prepared and their physical properties studied by ultraviolet–visible and infrared spectroscopy, mass spectrometry, magnetic susceptibility measurements, and X-ray diffraction. The compounds are monomeric and the physical properties may be explained if the rhenium atom sits in an essentially octahedral ligand field. Re(hfac)3has a hexagonal unit cell and the acetyl-acetone complex adopts the monoclinic cell of the α-form of the three typical crystal structure types which Astbury (1) observed for trispentane-2,4-dionatometal(III) compounds. The properties observed for trispentane-2,4-dionatorhenium(III) differ from those reported previously (2, 3). The difficulties experienced in obtaining pure Re(C5H7O2)3were caused by the ease with which the material is oxidized.

ISSN:0008-4042    

DOI:10.1139/v72-002

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

The alkylation of indol-2(3H)-one (oxindole) and of some of its mono and dialkyl derivatives has been investigated.Chromatographic methods for preparative separation and quantitative determination of the five compounds formed in the reaction between oxindole and benzyl chloride in the presence of a base are reported.A kinetic approach to these reactions shows that in unsubstituted indol-2(3H)-one the 3-position is twice as reactive as the 1-position. In the already 3-monosubstituted compound the reactivity of the 3-position is about 30 times greater than that of the 1-position.

ISSN:0008-4042    

DOI:10.1139/v72-003

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

The second-order rate constants have been measured over a range of temperatures for the proton-transter reactions from di-(4-nitrophenyl)methane to ethoxide, isopropoxide, andt-butoxide ions in solvents consisting of the corresponding alcohols containing 10% toluene by volume. The activation parameters ΔH≠and ΔS≠have been calculated and an interpretation of them is given in terms of solvation effects during the activation process. A comparison between the activation parameters for proton transfers and E2 olefin-forming β-elimination reactions is made and discussed with respect to transition state character of the latter reactions.

ISSN:0008-4042    

DOI:10.1139/v72-004

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Diffusion coefficients in air at 298.2 °K and 1 atm pressure are reported for ethane, ethene, ethyne, cyclopropane, propene, propadiene, propyne, butane, 1-butene, 2-methylpropene,cis-2-butene,trans-2-butene, 1,3-butadiene, 1-butyne, 2-methylbutane, 2,2-dimethylpropane, cyclopentane, and 1-pentene.A linear relationship, valid for alkanes and alkenes, has been found between the diffusion coefficient and the reduced molecular weight of the members of a homologous series and air.Diffusion coefficients calculated by ten prediction equations were generally lower than those observed.

ISSN:0008-4042    

DOI:10.1139/v72-005

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

The i.r. and Raman spectra of liquid and crystalline SiH4and SiD4–SiH4mixtures have been recorded. The spectra show striking changes when the crystal undergoes the solid–solid phase transition. Phase I is disordered. Possible site, and factor groups for the low temperature crystalline phase are proposed.

ISSN:0008-4042    

DOI:10.1139/v72-006

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

The 9.5 GHz electron spin resonance (e.s.r.) spectra of single crystal and powder samples of γ-irradiated taurine,, have been recorded. Overlapping spectra from three distinct radicals are present. The first of these is the species SO3−with an isotropicg-value of 2.0035 and a33S hyperfine coupling tensor with principal values 135.2, 99.2, and 97.9 G. The second radical is a π-electron species with the unpaired electron mainly on carbon and exhibiting hyperfine interaction from at least four protons, probablyand with principalg-values 2.0021, 2.0027, and 2.0034. The third radical has principalg-values 2.0024, 2.0056, and 2.0097 and principal values of the33S hyperfine tensor of 49.6, 9.1, and 1.2 G. The proposed structure for this radical is

ISSN:0008-4042    

DOI:10.1139/v72-007

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

The pyrolysis of tetramethyltin has been studied in a toluene carrier flow system from 803–941 °K using total pressures of 10.6 to 52.4 mm. Contact times varied from 0.49 to 13.8 s and the amount of decomposition from 1.35–98.7%. The progress of the reaction was followed by measuring the amount of methane, ethane, ethylene, and ethylbenzene formed. No appreciable heterogeneous reaction was detected and the first order rates constants appear to have been determined at the high pressure limit. The quantity of undecomposed alkyl was also measured and was found to be in agreement with the product analysis if four methyl radicals are released for each molecule undergoing reaction.Least squares analysis giveswith an estimated uncertainty inEof ± 1 kcal mol−1. The activation energy should be a good approximation toD[(CH3)3Sn—CH3].

ISSN:0008-4042    

DOI:10.1139/v72-008

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

The photodecomposition of 1,1,1-trichloro-2,2-bis(5′-chloro-2′-methoxyphenyl)ethane (MPA) has been carried out both in solution and solid phase with exciting light > 300 nm. The major products of the solid phase photolyses are HCl and 1,1-dichloro-2,2-bis(5′-chloro-2′-methoxyphenyl)ethylene (MPE), 5,5′-chloro-2,2′-methoxybenzophenone (MPO), 1,1-dichloro-2,2-bis(5′-chloro-2′-methoxyphenyl)ethane (MPD), and 1-chloro-2,2-bis(5′-chloro-2′-methoxyphenyl)ethane (MPC). In liquid phase and in the presence of O2the photodecomposition yields many products, the major ones, in addition to HCl, being MPE, MPD, MPC, and MPO. In the absence of O2in liquid phase only HCl, MPD, MPC, and MPE were observed. In the O2free photolysis MPD and MPC are produced in larger quantity than MPE. A preliminary investigation has shown that MPE irradiated at λ > 300 nm also photodecomposes. A check carried out by the Canada Department of Agriculture indicates that MPA is a pesticide although it may not be as effective as DDT.

ISSN:0008-4042    

DOI:10.1139/v72-009

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

The isomerization of α-pinene in the vapor phase over alumina catalysts of varying acid strength has been studied. The isomerization proceeds via two parallel paths, one giving bi- and tricyclic products such as camphene, β-pinene, tricyclene, and bornylene and the other giving rise to monocyclic compounds such as dipentene, terpinolene, α-terpinene, γ-terpinene,p-cymene, andp-menthene. Dependence of the distribution of reaction products on space time reveals that camphene, β-pinene, tricyclene, dipentene, and terpinolene are the primary products. The acid strength of alumina catalysts has a remarkable influence on the selectivity ratio of bi- and tricyclic to monocyclic products, the strong acid sites favoring the formation of monocyclic products. From the study of the reactions of camphene and tricyclene over the same catalysts under similar conditions it has been concluded that the decrease in the selectivity ratio with increasing acid strength of the catalysts is mainly due to the further isomerization of the bi- and tricyclic compounds to monocyclic products which takes place only on the strong acid sites.

ISSN:0008-4042    

DOI:10.1139/v72-010

出版商:NRC Research Press    

年代:1972

数据来源: NRC