High purity mesoporous gamma-al(2)o(3) from kano kaolin in the presence of polyethylene glycol 6000 (peg-6000) surfactant

Mesoporous gamma-Al2O3 with large surface area and narrow pore size was synthesized from acid-leachates of calcined kaolin in the presence of polyethylene glycol 6000 (PEG-6000) surfactant at room temperature. The synthesized alumina was characterized by X-ray diffraction (XRD), Nitrogen adsorption-desorption, Fourier transform infra-red spectroscopy (FTIR), field emission scanning electron microscopy (FESEM) with energy-dispersive X-ray analysis (EDX), and thermogravimetric-Derivative thermal analysis (TG-DTA). High-purity mesoporous gamma-Al2O3 with large surface area of 365.1 m(2)/g, narrow pore size distribution centred at 5.3 nm and pore volume of 0.46 cm(3)/g was obtained at 500 degrees C. When the calcination temperature has increased to 700 degrees C, the surface area decreased to 272.9 m(2)/g. Crystallite size calculated using Scherer's equation revealed the average size of 4.33 and 4.12 nm for alumina calcined at 500 and 700 degrees C, respectively. The excellent pore structural properties (high surface area and large pore volume) of the synthesized mesoporous gamma-alumina in the present study will allow for higher loading of active catalytic phases, as such it can be used as catalyst support

Ab initio vs molecular mechanics thermochemistry: Homocubanes

10.1021/ci0300285Journal of Chemical Information and Computer Sciences443903-906JCIS

BBD optimization of K-ZnO catalyst modification process for heterogeneous transesterification of rice bran oil to biodiesel

Environmentally benign zinc oxide (ZnO) was modified with 0-15% (wt.) potassium through wet impregnation and used in transesterification of rice bran oil (RBO) to form biodiesel. The catalyst was characterized by X-Ray powder Diffraction (XRD), its basic sites determined by back titration and Response Surface Methodology (RSM) Box-Behnken Design (BBD) was used to optimize the modification process variables on the basic sites of the catalyst. The transesterification product, biodiesel was analyzed by Nuclear Magnetic Resonance (NMR) spectroscopy. The result reveals K-modified ZnO with highly increased basic sites. Quadratic model with high regression R2 = 0.9995 was obtained from the ANOVA of modification process, optimization at maximum basic sites criterion gave optimum modification conditions of K-loading = 8.5% (wt.), calcination temperature = 480 oC and time = 4 hours with response and basic sites = 8.14 mmol/g which is in close agreement with the experimental value of 7.64 mmol/g. The catalyst was used and a value of 95.53% biodiesel conversion was obtained and effect of potassium leaching was not significant in the process