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Full-Text Articles in Engineering
Sio2-Included Cesium Polyoxotungstate Catalysts For Oxidation, W Trakarnpruk, W Kanjina
Sio2-Included Cesium Polyoxotungstate Catalysts For Oxidation, W Trakarnpruk, W Kanjina
Journal of Metals, Materials and Minerals
SiO2-included cesium polyoxotungstate catalysts were synthesized by a sol-gel method and characterizied by FTIR, XRD and N2 adsorption isotherms. XRD patterns prove that the cesium polyoxotungstate is uniformly dispersed in the silica network. The catalysts were used in oxidation of cyclohexane with H2O2. The products are cyclohexanol and cyclohexanone. The catalysts prepared by using a copolymer surfactant show higher surface area and exhibit higher activity. These catalysts are truly heterogeneous and can be reused at least 3 times.
Preparation And Catalytic Property Of High Surface Area Mixed Oxides From Calcination Of Mgcucr- And Mgcual-Layered Double Hydroxides, W. Trakarnpruk
Preparation And Catalytic Property Of High Surface Area Mixed Oxides From Calcination Of Mgcucr- And Mgcual-Layered Double Hydroxides, W. Trakarnpruk
Journal of Metals, Materials and Minerals
In this research work layered double hydroxides (LDHs) containing Mg, Cu and Cr(or Al) were prepared with starting Mg:Cu:Cr (or Al) molar ratio of 2:1:1. They were calcined at 500 ºC for 5 h to convert into corresponding mixed oxides possessing high surface area. The catalysts were characterized by chemical analysis (ICP), infrared spectroscopy (FTIR), thermal analysis (TGA/DTA), powder X-ray diffraction (XRD), surface area measurements and H2 temperature programmed reduction (TPR). Catalytic property of these mixed oxides catalysts were tested in the oxidation of ethylbenzene using tertbutylhydroperoxide as an oxidant without added solvent. The experimental results show that high conversion …
Extraction Of Tin From Hardhead By Oxidation And Fusion With Sodium Hydroxide, C Bunnakkha, C Jarupisitthorn
Extraction Of Tin From Hardhead By Oxidation And Fusion With Sodium Hydroxide, C Bunnakkha, C Jarupisitthorn
Journal of Metals, Materials and Minerals
In this research work, the extraction of tin from tin-iron alloy or hardhead which is the intermediate product obtained during tin smelting was investigated. The hardhead containing 32.40 wt% Sn and 45.81 wt% Fe was ground to different sizes and oxidized at 500 to 800 °C for 1 to 6 hours to form SnO2 and Fe2O3. The results indicated that an increase in oxidation temperature decreased the required oxidation time. However using too high oxidation temperature (800 °C) resulted in sintering of the oxide product.In sodium hydroxide fusion stage, effects of fusion temperature, fusion time, NaOH quantity and oxide product …
Oxidation Of Cyclohexane And Ethylbenzene By Hydrogen Peroxide Over Co-Substituted Heteropolytungstate Catalyst, W Kanjina, W Trakarnpruk
Oxidation Of Cyclohexane And Ethylbenzene By Hydrogen Peroxide Over Co-Substituted Heteropolytungstate Catalyst, W Kanjina, W Trakarnpruk
Journal of Metals, Materials and Minerals
The tetrabutylammonium salt of Co-substituted heteropolytungstate, [(n-C4H9)4N]4 HPW11Co(H2O)O39.3H2O was synthesized and characterized. It was shown to be an active catalyst for the oxidation of cyclohexane and ethylbenzene. The oxidation reactions were performed using green oxidant hydrogen peroxide and acetonitrile as solvent. The major products of the oxidation of cyclohexane were cyclohexanone (K) and cyclohexanol (A). High selectivity towards K-A oil was achieved. At longer time cyclohexanol was converted to cyclohexanone. Ethylbenzene was also selectively oxidized to acetophenone. These oxidation reactions appear to be radical processes since they were totally inhibited in the presence of radical scavenger.