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Title: Synthesis of ZSM 5 in alkaline and fluoride media characterization and catalytic activity
Researcher: Hariharan S
Guide(s): Sarojadevi, M.
Keywords: Zeolites, fluoride media, catalytic activity, p-diethyl benzene, o-diethyl benzene, crystallinity, p-dialkyl benzene
Upload Date: 30-Jan-2014
University: Anna University
Completed Date: 
Abstract: Zeolites, an important class of micro porous materials, have been used as catalysts, ion exchangers and adsorbents. They are built with SiO4 and AlO4 tetrahedra. Cerium AlPO-5 molecular sieves were synthesized and reported for oxidation of ethyl benzene and toluene. Since cerium entered the framework of AlPO-5, it was expected same entry in the framework of Silicalite-1. With this logic, in the present study Ce-Silicalite-1 molecular sieves and study of their activity for vapour phase oxidation of ethyl benzene and p- xylene were attempted in air. The major products were p-diethyl benzene (p-DEB) and ethyl benzene (EB), and minor products m- and o-diethyl benzene (m-DEB and o-DEB). The study of time on stream indicated very slow decrease in conversion with the increase in time on stream, but the selectivity of p-DEB increased due to partial blocking of pore with coke. Hence for selective formation of p-dialkyl benzene, high crystallinity and large crystal size were proved crucial. The WHSV was 5.776 h-1 and air flow rate 8ml h-1, acetophenone was 99 % selectivity at 300 °C. Cerium silicalite-1 (50) was more active (48 % conversion) than others. The study of time on stream indicated steady conversion with high selectivity to acetophenone for 6 h. It established absence of coke formations. The major product was p-methyl benzaldehyde. The conversion of p-xylene was 59 % at 300 °C. The other product p-methyl benzyl alcohol was very insignificant. The activity of the catalyst followed the order Ce-Silicalite-1, (50gt75gt100). The study of time on stream indicated study p-xylene conversion and p-methyl benzaldehyde selectivity. Hence the study indicated feasibility of incorporating cerium in the framework of Silicalite-1. Hence ZSM-5 synthesized in fluoride medium was established to have high p-selectivity in alkylation and disproportionation. Ce-Silicalite-1 molecular sieves, synthesized in the fluoride medium, also exhibited high selectivity in the oxidation of alkyl aromatics in air. newline newline newline
Pagination: xxi, 140
Appears in Departments:Faculty of Science and Humanities

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07_chapter 2.pdf194.31 kBAdobe PDFView/Open
08_chapter 3.pdf561.12 kBAdobe PDFView/Open
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10_chapter 5.pdf45.26 kBAdobe PDFView/Open
11_chapter 6.pdf54.26 kBAdobe PDFView/Open
12_chapter 7.pdf46.61 kBAdobe PDFView/Open
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14_chapter 9.pdf29.26 kBAdobe PDFView/Open
15_references.pdf79.49 kBAdobe PDFView/Open
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17_vitae.pdf13.33 kBAdobe PDFView/Open

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