Showing papers in "Journal of Catalysis in 1968"

TL;DR: In this article, the infrared spectra of pyridine adsorbed on the alkali and alkaline earth cation forms of Y zeolite have been studied and the results show that the number of Bronsted acid sites increases with decreasing cation radius and increasing electrostatic potential and field.

TL;DR: In this paper, the surface area and hydrogen chemisorption measurements made on palladium-black samples were used to determine surface areas of particles of a size where other techniques, such as electron microscopy, X-ray linebroadening and small-angle scattering, often fail through interference of the support.

TL;DR: In this article, the authors used the uncorrected Kelvin equation to calculate cylindrical pore distributions from the desorption branch of nitrogen sorption isotherms with the aid of a corrected form of the Kelvin equation.

TL;DR: In this paper, supported platinum consisting of 15-A crystallites has been prepared by reduction of platinum ammine ions adsorbed on the surface of silica gel, which has been carried out by hydrogen chemisorption, X-ray diffraction, and electron microscope techniques.

TL;DR: In this paper, the surface state changes in supported chromia catalysts were studied and a method was extended to determine the oxidation state of the surface in situ during reaction, and a tentative explanation was offered for the selectivity for oxygen over nitric oxide in the oxidation-reduction reactions on commonly employed catalysts.

TL;DR: In this paper, the reaction of neopentane on supported platinum and platinum powder catalysts has been obtained at 300 °C, 1 atm total pressure, and a hydrogen-to-neopentanes ratio of 10.

TL;DR: In this article, carbon dioxide chemisorption studies at 0 °C were used to determine the relative basicities of alkali-promoted reduced magnetite catalysts, showing that a higher surface basicity correlates with a lower methane selectivity in the Fischer-Tropsch synthesis.

TL;DR: In this paper, the authors extended the analysis of the adsorption branch of a nitrogen sorption isotherm to the model of spheroidal cavities, and the results of the cumulative calculations were shown to be satisfactory in appropriate cases.

TL;DR: In this article, the curvature of the meniscus is dependent on the distance to the walls of the pore and taking into account this dependence leads to a different shape of the maniscus from the hemispherical shape generally assumed for cylindrical pores.

TL;DR: In this article, a new method to prepare Bi 2 O 3 -MoO 3 catalysts consisting in boiling slurries of mixtures of freshly prepared and thoroughly washed bismuth hydroxide and molybdic acid has been developed.

TL;DR: In this article, the specific catalytic activity of rhenium and technetium was investigated for hydrogenation of benzene to cyclohexane. But the performance of the catalysts was not analyzed.

TL;DR: In this article, the phase distribution of equilibrated copper-nickel films with equal surface compositions has been analyzed and shown to be a constant multiplicity over the alloys of equal surface composition.

TL;DR: In this article, the authors studied the chemisorption of hydrogen sulfide on some nickel catalysts in the temperature range 550-645 °C and showed that a saturation layer was formed at ratios above 5 × 10−6, approximately, and at ratios at 10−3 bulk sulfide (Ni2S3) was formed.

TL;DR: In this article, the activities of synthetic Y faujasites, mordenites, and L zeolite for cracking n -hexane n -heptane, and ethylbenzene were determined using a pulse microreactor.

TL;DR: In this paper, the influence of chemical structure of the hydrocarbon molecule on the catalytic process is discussed, and the conditions required for heterogeneous thermal ignition are studied. But the results of the analysis are limited.

TL;DR: In this article, it was found that SnO 2, contacted around 450 °C with a gas saturated with MoO 2 (OH) 2, sorbs MoO 3 (or a hydrated form) to its surface.

TL;DR: The decomposition of rhodium, indium, and ruthenium chloride hydrates in air and in hydrogen has been studied by means of thermogravimetric analysis; additional studies have been made of their reduction when dispersed on low and high-area substrates as discussed by the authors.

TL;DR: In this article, it was shown that the reaction rate of SO2 on a sodium-potassium-vanadium catalyst also proceeds via rapid establishment of the equilibrium, SO2 + 2V5+ + O2− SO3+ 2V4+ (equilibrium constant K) and the reaction of oxygen with V4+ is the rate determining step.

TL;DR: In this article, a steady state mechanism involving simultaneous reduction and reoxidation of the catalyst surface with gaseous oxygen is suggested for the catalytic ammoxidation from propylene to acrylonitrile.

TL;DR: In this paper, the influence of adsorption on capillary evaporation of nitrogen from slit-shaped pores is discussed quantitatively and the application of the corrected Kelvin equation to the calculation of pore-size distribution functions from nitrogen sorption isotherms is discussed.

TL;DR: The influence of small amounts of water on the acidity of several alkali, alkaline earth, hydrogen, and mixed cation zeolites has been studied by observing changes in the infrared spectrum of chemisorbed pyridine as mentioned in this paper.

TL;DR: In this paper, the volume and size of interparticle pore systems are shown to be directly dependent on the size of the ultimate particles. But the size and volume of the pore system formed by larger particles can be affected by extrusion and tableting techniques.

TL;DR: In this article, the same rate equation was found empirically in the case of methanol and ethanol to ether and of tert-butanol to olefin, and the selectivity with respect to both types of compounds was regarded as a function of the thermal stability of the respective surface alkoxides.

TL;DR: The most active catalysts were those prepared from calcium hydroxide and calcined at 500 ° as discussed by the authors, which showed no catalytic activity towards the isomerization of olefins, the activity however could be restored when the catalyst was annealed at 500°.

TL;DR: In this article, a procedure for determining the reduction characteristics of metal oxide-promoted catalysts is described, which involves circulating a measured volume of hydrogen in a closed system that includes a suitable tube for the catalyst, an absorption tube for removing the water formed, and a manometer for measuring the consumption of hydrogen.

TL;DR: In this article, a comparison between microcatalytic and steady state flow reactor data for the dehydration of 2-butanol over a series of hydroxyapatite catalysts is made.

TL;DR: The infrared spectra of magnesium ammonium y zeolite have been observed after calcination at temperatures up to 800 °C as mentioned in this paper, where the concentration of pyridinium ion parallels that of the hydroxyl groups represented by the 3643-cm −1 absorption band and is a measure of the Bronsted acid site concentration.

TL;DR: In this article, a new type of activity was found to set in at the 60% level of exchange (Ca2+ for Na2+) for high Ca2+ (>60%) catalysts.