Isomerization of butenes on some ZnO-, NiO- and Cr2O3- containing catalysts and the effect of controlled impurities and of potash additions

Cvetanović, R. J.; Foster, NR

doi:10.1039/df9592800201

Cited by 7 publications

(3 citation statements)

References 4 publications

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“…The average distance between Cz and An can be calculated using the F€ orster mechanism. 17 By measuring the energy transfer efficiency, we were able to determine the average distance between the Cz and the An in the powders prepared using a mixture of the two molecules. If the PS chains are coupled with one another, this average distance should be short.…”

Section: Articlementioning

confidence: 99%

“…This effect is due to the proximity of the Cz to the An, which permits the transfer of excitation energy between them. The average distance between Cz and An can be calculated using the Förster mechanism . By measuring the energy transfer efficiency, we were able to determine the average distance between the Cz and the An in the powders prepared using a mixture of the two molecules.…”

Section: Introductionmentioning

confidence: 99%

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Detection of Interchain Proximity and Segmental Motion of Polymer Glass

Chen

et al. 2011

Macromolecules

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We used fluorescence nonradiative energy transfer (NRET) to detect the interchain distances r at the overlapping regions of polymer chains. Freeze-dried polystyrene (PS) is found to have an increased r value and thus a reduced chain packing density, which shows an increased segmental mobility under uniaxial compression. We clarify that it is the interchain coupling that restricts the chain motion in a glassy oligomer in which chain entanglement is absent.

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Section: Articlementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Detection of Interchain Proximity and Segmental Motion of Polymer Glass

Chen

et al. 2011

Macromolecules

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“…As a possible alternative to leaching out "active sites" we attenlpted to block them. (a) Unsupported nickel oxide is considered to be inactive as a butene isornerization catalyst below 400" (11). We found that when 1-butene was adsorbed on Vycor impregnated with -2% nickel oxide, neither the isomerization nor the polymerization rates were significantly affected and the system behaved in every respect like that shown in Ethylene, which did not polymerize on Vycor alone, did so when nickel oxide was present, giving rise to a trans-2-butene spectruin (4).…”

Section: (V) Adsorption Sites Strllctzlre Of Adsorbed Butenesmentioning

confidence: 99%

An Infrared Study of the Adsorption of Butenes on Surfaces of Porous Vycor Glass

Little¹,

Klauser²,

Amberg³

1961

Can. J. Chem.

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The adsorption and reactions of the four butenes on porous Vycor glass a t room temperature have been studied by infrared spectroscopy. Initial adsorption was rapid and was found to perturb the surface hydroxyl groups of the glass. In the case of the n-butenes rapid isomerization took place a t room temperature. In addition to this the adsorbate spectra showed the occurrence of a slower reaction which led to an increase in saturated C-H groupings. Cs and higher con~pounds were shown to have formed; on outgassing a t room temperature small amounts of cracking products were collected. The polymerization of isobutene was particularly rapid. Experimeilts a t low coverage (0 -0.001-0.002) gave identical initial spectra for the n-butenes. These were discussed in terms of possible models for butene adsorption. A reduction in the alumina and zirconia content of the glass by acid leaching resulted in decreased rates of isomerization and polymerization, suggesting that one or both of these oxides are a t least partially responsible for the activity of the glass. A pure silica aerogel was almost completely inactive. Quantitative measurements of the spectra of several monoolefins in solutioil were made for comparison with the surface species, in particular with respect to their inolar intensities of absorption.

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