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Zero-field NMR studies of physically admixed Co/Co-ThO2 ZSM-5 catalysts (1987)

Murty, A. N. ; Williams, A. A. ; Obermyer, R. T. ; [et al.]

[S.l.] : American Institute of Physics (AIP)

Journal of Applied Physics 61 (1987), S. 4361-4363

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ISSN: 1089-7550

Source: AIP Digital Archive

Topics: Physics

Notes: The Co-ZSM-5 and Co-ThO2-ZSM-5 catalysts are a particularly promising group of bifunctional zeolite catalysts used for the conversion of synthesis gas to gasoline-range hydrocarbons. Catalytic properties of these materials, such as activity and selectivity, depend upon the amount of the cobalt on the medium-pore zeolite ZSM-5, as well as upon the presence of promoters such as ThO2. These studies were undertaken to ascertain the effect of thoria upon the magnetic and structural nature of these catalysts. Zero-field nuclear magnetic resonance measurements have been made on a series of zeolite cobalt and cobalt-thoria catalysts with three different concentrations of Co (3, 6, and 9 wt. %). The catalysts were prepared by making physical admixtures of precipitated cobalt, or cobalt-thoria, and ZSM-5. The amount of thoria introduced ranged from 0.5 to 1.5 wt. %. After reduction of the catalyst samples, the normal metallic cobalt resonance line at 213.0 MHz (fcc) and the fault lines at 215.5 and 218.6 MHz were observed. In the unpromoted catalysts, a line at 210.7 MHz, which is lower than the fcc line frequency, and another line at 221.6 MHz, which is higher than the hcp line frequency, were observed. When the promoter thoria was added, there was a systematic absence of the hcp line in the unused catalyst. Previous catalytic tests had shown that small amounts of the promoter thoria (0.4 wt. %) significantly increase the liquid hydrocarbon yields. The change in catalytic behavior can be related to the changes in crystallite species and crystallite size.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1063/1.338421

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Optimization of colour in commercial port blends (1986)

WILLIAMS, A. A. ; BAINES, C. R. ; FINNIE, M. S.

Oxford, UK : Blackwell Publishing Ltd

International journal of food science & technology 21 (1986), S. 0

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ISSN: 1365-2621

Source: Blackwell Publishing Journal Backfiles 1879-2005

Topics: Process Engineering, Biotechnology, Nutrition Technology

Notes: Simple quantitative descriptive analysis coupled with ratio scaling techniques were used by a consumer panel for the objective assessment of fifteen ports, derived from blending Ruby, Tawny and White ports in varying proportions, for redness, brownness and intensity of colour. Deviation of the amounts of these attributes from those in the consumer's concept of an ideal port, both for Ruby and Tawny drinkers, was determined in relation to blend composition and L*, a* and b* values. Inverse simultaneous regression procedures showed the ports which best satisfied the two consumer subsets (Ruby and Tawny drinkers), in respect to all the sensory attributes, had chroma values of 23.0 and 21.8, and hue angles of 37.3 and 45.1° respectively. This corresponded to L*, a* and b* values of 86.13, 18.24 and 13.9 for the Ruby drinkers, and 92.1,15.3 and 15.4 for the Tawny drinkers.