Methane adsorbed

Ventura, S. C., Hum, G.P. and Narang, S.C., Novel Strategies for the Synthesis of Methane Adsorbents with Controlled Porosity and High Surface Area", Gas Research Institute Report GRl-93/0018, 1993... 

The authors showed that the Grabke-type kinetic model can explain the results at a low carbon activity for Ni-Cu catalysts, but that at higher carbon activities, the rates for the Ni0 9Cu0 j catalysts are higher than the model-predicted rates. Low-temperature decomposition of methane over the silica-supported Ni catalyst has been reported by Kuijpers et al. [101]. It was demonstrated that at temperatures as low as 175°C, methane adsorbed on the Ni catalysts dissociates completely into adsorbed carbon atoms and hydrogen. 

Nuclear magnetic resonance measurements of methane adsorbed to various coverages on titanium dioxide have been made by Fuschillo and Renton 16). At a coverage of 0.95 monolayer and at 20.4°K, the X-point for solid bulk methane, these authors observed an abrupt change in the proton resonance line width, presumably due to translational and rotational diffusion of methane molecules. For pure, bulk methane no change has been observed in the line width at the X-point. 

The spectra of methane, adsorbed at 90° K., showed a weak band at 2,899 cm.", in addition to a strong band (vt) at 3,006 cm. h This weak band was assigned to the I l symmetrical breathing frequency of methane, which is normally observed only in the bulk state in the Raman spectrum at 2,916 cm. h No over-all dipole change is associated with the vi vibration consequently, it is forbidden in the infrared spectra of liquid and gaseous methane. The appearance of this band is a direct measure of the... 

In Mordenite. Smit and den Ouden (60, 144) reported a Monte Carlo investigation of methane adsorbed in mordenite of varying Si/Al ratios. In their calculations, both the zeolite and sorbate were held rigid, infinite dilution was assumed, and sorbate-zeolite interaction parameters were taken from Kiselev et al. (79). Electronic neutrality of the zeolite framework was preserved by compensating the trivalent aluminum exactly with sodium cations, located in experimentally determined crystallographic locations. 

Logarithmic plots of the Freundlich equation, Q = kpn, where Q is the amount of methane adsorbed at a pressure p, and k and n are constants, for methane adsorption at 0°, 30° and 50°C. in Figures 6 and 7 indicate that the equation is valid up to at least 1000 torr. Equilibrium sorption points obtained on different samples in a manostatic adsorption apparatus are shown as solid points in Figures 6 and 7. The exponent n varied from 0.72 at 0° to 0.87 at 50°C. for the Pocahontas coal and from 0.78 at 0° to 0.94 at 50°C. for Pittsburgh coal (Table III). 

As an example of the extreme energy resolution possible with inelastic neutron sattering, we include some recent experiments of Newbery et (17) on methane adsorbed on graphitized carbon blacks. Using a time-of-flight spectrometer and an incident... 

Fig. 8. IR spectra in the C-H stretching region of methane adsorbed on MgO at 80 K (MgO pretreated in 02 at 773 K, followed by evacuation at 773 K) [reproduced from Knozinger (15) with permission of VCH],...

Fig. 30. Self-diffusion coefficient of methane adsorbed on ZSM-5 as a function of coadsorbed benzene (3 CH4 per u.c., 293 K) (86).

A. Molecular Self-Diffusion of Methane Adsorbed on ZSM-5 Containing Coadsorbed Benzene... 

A. Alavi, Molecular Dynamics Simulation of Methane Adsorbed in MgO Evidence for a Kosterlitz-Thouless Transition, Mol. Phys. 71 (1990) 1173-1191 Evidence for a Kosterlitz-Thouless Transition in a Simulation of CD4 Adsorbed on MgO, Phys. Rev. Lett. 64 (1990), 2289-2292. A. Alavi and I. R. McDonald, Molecular Dynamics Simulation of Argon Physisorbed on Magnesium Oxide, Mol. Phys. 69 (1990) 703-713. 

J. M. Phillips and T. R. Story, Commensurability Transitions in Multilayers A Response to Substrate-Induced Elastic Stress, Phys. Rev. B 42 (1990) 6944-6953 C. D. Hruska and J. Phillips, Observed Microscopic Structure in the Simulation of Multilayers, Phys. Rev. B 37 (1988) 3801-3804 J. M. Phillips and C. D. I oiska, Methane Adsorbed on Graphite. IV. Multilayer Growth at Low Temperatures, Phys. Rev. B 39 (1989) 5425-5435 J. M. Phillips, Layer by Layer Melting of Argon Films on Graphite A Computer Simulation Study, Phys. Lett. A 147 (1990) 54-58 J. M. Phillips, The Structure near Transitions in Thin Films, Langmuir 5 (1989) 571-575. 

---