Sulfated zirconia (SZ), unpromoted and promoted with 0.5–2.0 wt% Mn or Fe, was investigated by in situ IR and UV–vis spectroscopy during activation at 723–773 K and interaction with n-butane at 298–323 K. During start-up of the catalysts, the isomerization rate increases with the amount of water that is being formed, consistent with an activation of n-butane via oxidative dehydrogenation. Sulfa...

Two sulfated zirconia catalysts were prepared via sulfation and calcination at 873 K of zirconium hydroxide aged at room temperature for 1 h (SZ-1) or aged at 373 K for 24 h (SZ-2). SZ-1 was active for n-butane isomerisation at 373 K; SZ-2 reached similar performance only at 473 K. Both materials contained about 9 wt% sulfate and were tetragonal. Due to a BET lower surface area (105 m/g vs. 148...

Recently, dimethyl ether (DME) has been paid much attention as a clean fuel. DME has many advantages as a substitute for liquefied petroleum gas (LPG). Sulfur oxides (SOx), and particulate matters (PM) are not produced at the combustion. Infrastructures and equipments for LPG can be used with slight improvements, because physical properties of DME are similar to those of light hydrocarbons, pro...

A method to characterize the surface sites of catalysts in their active state by adsorption microcalorimetry was developed. A calorimeter cell was used as a flow-type reactor, and the skeletal isomerization of n-butane (1 kPa) at 378 K and atmospheric pressure proceeded at comparable rates and with the same states of induction period, maximum and deactivation phase as in a tubular reactor. The ...

To efficiently recover the waste heat from a diesel engine exhaust, a regenerative organic Rankine cycle (RORC) system was employed, and butane, R124, R416A, and R134a were used as the working fluids. The resulting diesel engine-RORC combined system was defined and the relevant evaluation indexes were proposed. First, the variation tendency of the exhaust energy rate under various diesel engine...

BACKGROUND Bacterial production of anionic sulphide is increased in the colon of ulcerative colitis and sulphides can cause metabolic damage to colonocytes. AIMS To assess the reversal of the damaging effect of sulphide to isolated colonocytes by methionine and methionine derivatives. METHODS AND SUBJECTS Isolated colonocytes were prepared from rat colons and 12 human colectomy specimens. I...

The selective oxidation of n-butane to maleic anhydride over V-P-O mixed oxides was studied under oxygen deficient conditions. The mixed oxides were prepared with P/V atomic ratios ranging from 0.7 to 1.0. Catalysts with P/V (1.0 did not show any selectivity to maleic anhydride formation, regardless of whether or not (VO)2P207 was present. For catalysts with P/V = 1.0, containing by &e actual s...