Showing papers on "Vapours published in 1976"

Reactions of transition-metal vapours with cycloheptatriene and cyclo-octatetraene

Abstract: The co-ordination of cycloheptatriene in reactions with transition-metal atoms in the condensed phase at low temperature is accompanied by extensive hydrogen migration. Thus, condensation of C7H8 with the vapours of Ti, V, Cr, Fe, and Co affords [Ti(η-C7H7)(η5-C7H9)], V(C14H16), [Cr(η-C7H7)(η4-C7H10)], [Fe(η5-C7H7)(η5-C7H9)] or FeC14H18, and CoC14Hn(n= 15, 17, or 19) respectively. No organometallic products have been isolated from vapours of Mn, Ni or Pd. Condensation of a PF3–C7H8 mixture with vapours of Cr or Co affords [Cr(C7H8)(PF3)3] or [Co(C7H7)(PF3)3] respectively. Condensation of C8H8 with vapours of Ti, Fe, and Co gives intractable polymers, but with chromium vapour [Cr2(C8H8)3] is obtained. The use of metal atoms in the preparation of olefinic metal complexes is compared with conventional reductive methods.

Apparatus for the continuous purification of exhaust gas containing solvent vapours

Abstract: An apparatus for purifying an exhaust gas containing solvent vapours by bringing the exhaust gas and adsorbent particles into continuous mutual contact to adsorb the solvent vapours onto the adsorbent particles and subsequently regenerating the adsorbent particles containing the solvent vapours thus adsorbed and simultaneously recovering the solvent vapours. In regenerating the adsorbent particles containing the solvent vapours, the apparatus is capable of advantageously using an incondensable inert gas as a carrier gas for regenerating the adsorbent particles.

Condensation of binary mixtures of vapours of immiscible liquids

Abstract: The condensation of mixtures of vapours of immiscible liquids is a process which occurs frequently in the oil and chemical process industries, particularly where such processes as steam distillation, heterogeneous azeotropic distillation and solvent drying are used. Yet the process is not understood. The discrepancies between the heat transfer coefficients reported by previous workers in this field are so large that none of the published correlations can be confidently used for design purposes. The relationships found between heat transfer coefficient and temperature driving force differ so widely that it is impossible to predict., without prior experimentation, the behaviour of condensers when operating conditions are changed. The present state of knowledge in this field is such that it is not known whether the factor controlling heat transfer rate during condensation is simply the conductive resistance of the condensate layer, or whether the conditions at the vapour–liquid interface are of importance. A need for further work in this field is obvious. The work described in this thesis covers the design and development of an apparatus to investigate the process of condensation of mixtures of vapours of immiscible liquids and an experimental study in which local heat transfer coefficients have been measured and related to visual observations of the condensate flow pattern.

Populations of excited states in flash-heated vapours

Abstract: The populations of excited states in the vapours of barium and calcium produced by the flash pyrolysis technique have been investigated by means of the hook method. For low-lying states (within about 2 eV of the ground state) the populations some 500 mu s after the beginning of the pyrolysis flash were found to follow the Boltzmann distribution at a temperature which for our particular experimental conditions was about 5000 K. The reproducibility is such as to make this a suitable source for the determination of relative oscillator strengths for lines originating on these low-lying levels. The degree of ionization, however, is significantly below that to be expected in thermal equilibrium at this temperature.