Various metal-modified HMOR catalysts for the carbonylation of dimethyl ether (DME) were prepared by ion exchange with Cu, Ni, Co, Zn, or Ag. The catalysts were characterized by the Brunauer−Emmett−Teller method, X-ray diffraction measurements, transmission electron microscopy, X-ray photoelectron spectroscopy, nuclear magnetic resonance spectroscopy, temperature-programmed desorption of ammonia, and temperature-programmed oxidation. We found that the pore structure of mordenite (HMOR) was well maintained and that the metal species were highly dispersed on the zeolite. On HMOR subjected to ion exchange with Cu, Ni, Co, or Zn, the metal ions were mainly at the zeolite exchange sites with some corresponding metal oxides. Some Brønsted acid sites were converted to Lewis acid sites, and some strong acid sites were formed together. HMOR modified with Cu, Ni, or Co showed good catalytic performance, with Cu/HMOR exhibiting the highest performance. DME conversion and methyl acetate selectivity were close to 100% under the optimum reaction conditions, which is attributed to the joint participation of Brønsted acid sites contributing to DME conversion and metal Lewis acid sites contributing to CO binding, along with the appropriate coordination structure. Modification with Cu not only improved the catalytic activity, but also suppressed carbon deposition and extended the catalyst lifetime.

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Experimental measurements of thermal conductivity of wood were performed using the heat flow meter and transient plane source technique. The specimens were prepared from five species of both softwoods and hardwoods widely available and used in China, with a wide range of density and moisture content. The transverse thermal conductivity of ovendry specimens is presented as a function of density and temperature up to 90°C and is compared with that along the grain direction for two select species. The influence of moisture content up to 23 percent, which is below the typical fiber saturation point of wood, on the transverse thermal conductivity is presented as well. It is shown that the transverse thermal conductivity of wood increases with density, temperature, and moisture content. Linear correlating equations are proposed in terms of these factors.