摘要:

The surface tensions, viscosities, and vapor pressures, total and partial, have been determined as functions of concentration for the following systems: (a) acetone – acetic anhydride; (b) acetone – carbon disulfide; (c) acetic anhydride – carbon disulfide; and (d) pseudo-binary mixtures of (a) and (b), whose compositions lie on a straight line tangential to the plait point of the ternary system.The general behavior of ideal and non-ideal systems, in regard to surface tension and viscosity is discussed. For the system acetone – carbon disulfide, whose vapor phase can be considered ideal, the activities, activity coefficients, excess free energies, enthalpies and entropies of mixing have been obtained from the vapor pressures. The vapor phase of the other three systems contains acetic anhydride which is associated in the vapor state, and for these systems the experimental data are reported without further calculation.

ISSN:0008-4042    

DOI:10.1139/v71-357

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Photolysis of CO2/neopentane mixtures with a bromine lamp was studied at room temperature to obtain chemical evidence for primary formation of O(1D2) atoms in the photolysis of CO2at close to 1600 Å. The trends in the effects of various added gases on the yield of neopentanol agreed well with those reported in the literature for the rates of deactivation of O(1D2) atoms. This agreement demonstrated O(1D2) formation in the photolysis of CO2at the wavelength used.

ISSN:0008-4042    

DOI:10.1139/v71-358

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

A free radical chain mechanism is presented to describe the kinetics of the pyrolysis of acetylene over the temperature range 700–2400 °K. The mechanism is based on the following initiation reactionand subsequent addition, abstraction, and decomposition reactions of the radicals involved are shown to account for the products observed and for the kinetic characteristics of the reaction.

ISSN:0008-4042    

DOI:10.1139/v71-359

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Independent formation cross sections of129Cs,130Cs,131Cs,134Csm,134Csm+g,136Cs,139Ce, and cumulative formation cross sections of141Ce and143Ce were obtained when235U was caused to fission with protons of energies varying between 20 and 85 MeV. The energies at which the excitation functions reached their maxima were related to the neutron-to-proton ratio of the fission products. These were compared with other fissioning systems. Charge dispersion curves were obtained from the cross section data. The variation of (ZA − Zp) with energy, both in magnitude and in trend, agrees extremely well with predictions made by Saha and Yaffe for nuclides in this mass range. Calculations forZpshow that good agreement is obtained with the unchanged charge division hypothesis. An estimate has been made of the total number of neutrons emitted in fission at these energies.

ISSN:0008-4042    

DOI:10.1139/v71-360

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

The reactions of the molecular ion have been studied as a function of the ion kinetic energy for methyl fluoride and methyl chloride. The following reactions are observedFor methyl fluoride (X = F) reactionscanddhave kinetic energy thresholds and become significant at high ion energies. For CH3Cl (X = Cl) reactionais not observed and reactionscanddare of only minor importance at high ion energies. Rate coefficients for the molecular ions and a number of fragment ions as well as rate coefficients for further reaction of CH4X+are reported.

ISSN:0008-4042    

DOI:10.1139/v71-361

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Alkyllithium reagents (RLi: R = methyl,n-butyl,t-butyl) add to norbornen-7-one either without stereochemical preference (R = n-butyl) or withsynattack favored. This addition selectivity is qualitatively the same as that shown by corresponding alkylmagnesium reagents but competition from reduction is much less important in the case of alkyllithium reagents.Phenyllithium and vinyllithium add preferentially from theantiface, although the corresponding Grignard reagents add selectively from thesynface. Possible causes of the stereoselectivities are considered. Solvent effects on the stereochemistry of addition are small.

ISSN:0008-4042    

DOI:10.1139/v71-362

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Normal coordinate calculations for methylene cyclopropane-h6and -d6have been carried out using two models. In the first model 31 internal coordinates were used, and in the second model 25 internal coordinates were used. The force constants were, in each case, refined to the 40 frequencies observed for the two molecules. Using the first model 26 force constants, of which four were constrained, fitted the frequencies with an average error of 1.2% for C4H6and 2.8% for C4D6. Using the second model 24 force constants, of which two were constrained, fitted the frequencies with an average error of 1.4% for C4H6and 2.8% for C4D6.The very low isotopic shift of the C=C stretching mode can be explained by an interaction with the ethylenic CH2deformation, which is best assigned at 1047 m−1, rather than at 1139 cm−1, in C4D6. The calculations indicate that the experimental assignment for theA1ring breathing mode and theA1methylenic wag in C4H6should probably be reversed. For theA1and theB1modes with frequencies between 500 and 1300 cm−1, the normal coordinates change considerably on deuteration. The symmetry coordinates are mixed in the normal modes of C4D6to a much greater extent than in those of C4H6.

ISSN:0008-4042    

DOI:10.1139/v71-363

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

The condensed products (at – 180 °C) of electrically dissociated water vapor and other related systems were examined by means of laser Raman spectroscopy. A new type of total reflection cell had to be developed for the study of metastable species trapped in an amorphous matrix. Besides the characteristic O—O stretching band of hydrogen peroxide at 878 cm−1, always the strongest, another fairly strong band at 500 cm−1, and a third one at about 760 cm−1were present in all cases. A couple of weaker bands around 820–830 cm−1and 430–440 cm−1occurred only in oxygen-rich system (H2O2vapor or H2O–O2mixtures). In the latter, the presence of condensed ozone was confirmed by a band at 1025 cm−1, and occasionally another faint one around 1120 cm−1.The relative intensities of the bands varied locally in a given sample, indicating uneven composition.Isotopic shifts with18O confirmed that these Raman bands arise from vibrations of oxygen atoms. Essentially the same results were obtained in hydrogen as in deuterium systems, except that in the latter case the new bands were appreciably stronger and sharper. The present results support the assignment of previous infrared spectra to hydrogen polyoxides, H2O3and H2O4.

ISSN:0008-4042    

DOI:10.1139/v71-364

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Dimethylsulfoxide is a dipolar aprotic solvent of high basicity having a large dielectric constant (ϵ = 48) but very low solvating power for negative ions. The radiation yield of "free ions" in this liquid is in accord with the dielectric constant,G(free ions) = 1.8 ± 0.2, but these "free ions" do not resemble the strongly solvated electrons found in other polar media such as water and aliphatic alcohols. Evidence for this conclusion is based principally on competitive reactions involving a wide range of scavengers in competition with nitrous oxide. The radiation yields of gaseous products from pure liquid dimethylsulfoxide areG(H2) = 0.20 ± 0.01,G(CH4) = 3.3 ± 0.1, andG(C2H6) = 0.49 ± 0.03.

ISSN:0008-4042    

DOI:10.1139/v71-365

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

The 4- and 5-monodeuterio and 4,5-dideuterio isothiazoles were prepared and their i.r. spectra recorded in different states, vapor particularly.The Raman spectrum of isothiazole was also measured; its analysis leads to the modification of the assignment of two of the fundamental modes previously described for this compound. The analysis of the i.r. spectra of the three deuterio isothiazoles is discussed.

ISSN:0008-4042    

DOI:10.1139/v71-366

出版商:NRC Research Press    

年代:1971

数据来源: NRC