摘要:

The kinetics of the addition of hydrogen fluoride to vinyl fluoride have been measured in the vapor phase at temperatures of 100 and 150 °C and under pressures of 170, 308, and 446 N/m2. The rate equation was found to be a typical second order expression, −dx/dt = k[CHF=CH2] [HF]. The energy of activation was calculated to be 17 ± 2 kcal/mol, and the frequency factor, logA(l/mol s) was 6 ± 1. Based on reaction data from the literature, equilibrium constants and a value for ΔH298were calculated. For this reaction, ΔH298is about −12 kcal/mol.

ISSN:0008-4042    

DOI:10.1139/v71-407

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

The phenomenon of chemiluminescent emission from atoms introduced into hydrocarbon flames has been studied in a basic hydrogen-oxygen diffusion flame at low hydrocarbon concentrations. Emissions from several atoms are first order in methane concentration and examination of the relative populations of the excited states of arsenic suggests a single excitation mechanism with available energy in excess of 8.5 eV. Previously proposed mechanisms are discussed and the available evidence favors the processas the origin of the energy of excitation.

ISSN:0008-4042    

DOI:10.1139/v71-408

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Molar excess enthalpies and volumes of the systems cyclopentane –cis-decalin and cyclopentane –trans-decalin at 25 °C were determined by direct calorimetric and dilatometric measurements. Excess Gibbs free energies, also at 25 °C, were obtained from a study of the vapor–liquid equilibria. The excess properties of these cyclopentane systems are compared with those of their cyclohexane counterparts, and are interpreted in terms of the theory of Flory.

ISSN:0008-4042    

DOI:10.1139/v71-409

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Kinetic and thermodynamic parameters have been determined for the σ-complex formation reactions between 1,3,5-trinitrobenzene and the lyate ions of water, methanol, ethanol,n- andi-propanol andn-,i-, andt-butanol in their respective solvents. Trends in these values are interpreted in terms of specific solvation effects associated with both the base and the σ-complex. Solvent and kinetic isotope effects associated with the σ-complex formation reactions of ethoxide with 1,3,5-trinitrobenzene and 1,3,5-trinitrobenzene-d3in ethanol and ethanol-O-dhave also been evaluated.

ISSN:0008-4042    

DOI:10.1139/v71-410

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

The molecular structure of 2-bromo-11-ethyl-5,9-dimethoxytetracyclo[5.4.1.14,12•18,11]tetradecan-3-one, C18H27BrO3, synthesized in an attempt to develop a method of conversion from an advanced relay compound to the alkaloid delphinine, has been determined by the heavy atom method. The compound crystallizes in the monoclinic system, space groupP21/c, with unit cell dimensionsa = 9.684(9),b = 13.481(15),c = 12.988(14) Å, β = 99.47(7)°, and four molecules in the unit cell. The atomic parameters were refined by block-diagonal least squares using anisotropic thermal parameters. The hydrogen atom positions were established but the parameters were not refined. The final agreement residual for 816 observed reflections isR = 0.044.The stereochemistry of the compound was found to be unsuitable for the delphinine synthesis.

ISSN:0008-4042    

DOI:10.1139/v71-411

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

The dichromate oxidation of methyl-7-methyl-6,8,11,13-podocarpatetraen-19-oate, (5), is reported.

ISSN:0008-4042    

DOI:10.1139/v71-412

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Combination of the Lewis bases Cp2MH2(where M = W or Mo) with the Group III Lewis acids AlR3(where R = Me, Et, or Ph) and AlMe2H has yielded a series of 1:1 complexes of the type Cp2MH2•AlR3. A number of the complexes undergoes a slow elimination of hydrogen or alkane in benzene solution. Attempts to isolate mixed hydride adducts of the type, Cp2MH2•M′H3(where M′ = Al or Ga), were unsuccessful.

ISSN:0008-4042    

DOI:10.1139/v71-413

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

The35Cl nuclear quadrupole resonance (n.q.r.) frequencies at 77 °K of twenty-two chloroformates, twenty-eight acid chlorides, two thiocarbonyl molecules, and five carbamyl chlorides are reported.

ISSN:0008-4042    

DOI:10.1139/v71-414

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

The X-band e.s.r. spectra of single crystal and powder samples of γ-irradiated dicyandiamide, (H2N)2CNCN have been observed. The results show that three radical species are formed on irradiation at room temperature. One of these radicals, which gives a single broad line spectrum of width 8.5 G and g = 2.0040, has not been identified. The other two species are considered both to have the same chemical formulabut one is a π-electron radical whereas the other is a σ-electron radical with a very large proton hyperfine splitting in the range of 73–81 G. The production of two types of radicals by radiation damage to the same —NH2group of dicyandiamide is explained in terms of the ease of formation of π- and σ-electron radicals as influenced by geometrical considerations stemming from the hydrogen bonding in the dicyandiamide crystal.

ISSN:0008-4042    

DOI:10.1139/v71-415

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Tin arsines which contain an As—H bond, namely trimethylstannylarsine, bis-trimethylstannylarsine, and phenyl(trimethylstannyl)arsine, have been prepared and characterized. Alternative preparations of other trimethylstannylarsines are also discussed.

ISSN:0008-4042    

DOI:10.1139/v71-416

出版商:NRC Research Press    

年代:1971

数据来源: NRC