Iron, Copper And Tin Incorporated Rice Husk Ash Silica : Preparation, Characterization And Application As Catalysts For Friedel-Crafts Benzoylation Reactions

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dc.contributor.authorHassan, Ishraga Abdelmoniem
dc.date.accessioned2018-08-07T08:21:23Z
dc.date.available2018-08-07T08:21:23Z
dc.date.issued2011-07
dc.description.abstractIron, copper and tin incorporated silica catalysts were prepared via sol-gel method using the silica extracted from rice husk ash. The modified catalysts were denoted as RHA-xFe (x = 5, 10, 15 and 20 wt.%), RHA-10Cu and RHA-10Sn. Prepared catalysts were characterized by various physico-chemical techniques such as XRD, FT-IR, N2-sorption, AAS, SEM-EDX, TEM, DR UV/Vis, solid state 29Si MAS NMR, EPR, TGA-FT-IR and FT-IR-pyridine adsorption. The catalysts were found to be amorphous. Elemental analysis confirmed the presence of the metals in the silica framework. The acidity studies on the catalysts by using FT-IR-pyridine adsorption demonstrated that, there is no Brønsted acid sites. However, it has mainly Lewis acid sites. The catalytic activity of RHA-xFe with different iron loadings was studied for liquid-phase benzoylation of p-xylene, anisole and toluene with benzoyl chloride as benzoylating agent. The effect of various reaction parameters such as iron loadings, catalyst mass, molar ratio of the reactants, reaction temperature, catalyst type, leaching of metal and catalyst reusability was discussed. Compared to other iron loadings, RHA-10Fe was found to be the most efficient catalyst in terms of conversion and selectivity. Comparison of catalytic activity of RHA-10Fe, RHA- 10Cu and RHA-10Sn in the benzoylation reaction of the aromatic compounds under the optimized reaction conditions was found to be in the order: RHA-10Fe >> RHA- 10Sn > RHA-10Cu. However, the products selectivity followed the order: RHA- 10Fe >> RHA-10Cu > RHA-10Sn for the benzoylation of p-xylene and toluene, while for the benzoylation of anisole as in the order: RHA-10Fe >> RHA-10Sn > RHA-10Cu. The homogeneous iron salt (Fe(NO3)3.9H2O) was tested for the reaction under the optimized conditions, and it showed higher activity over the heterogeneous catalysts (RHA-10Fe and RHA-10Fe(Cal)), whereas the highest desired product selectivity was obtained using RHA-10Fe(Cal) in the benzoylation reaction.en_US
dc.identifier.urihttp://hdl.handle.net/123456789/6232
dc.language.isoenen_US
dc.subjectIron, copper and tin incorporated silica catalystsen_US
dc.subjectsilica extracted from rice husk ashen_US
dc.titleIron, Copper And Tin Incorporated Rice Husk Ash Silica : Preparation, Characterization And Application As Catalysts For Friedel-Crafts Benzoylation Reactionsen_US
dc.typeThesisen_US
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