Characterization of the acidic properties of zeolites and their catalytic behavior in the synthesis ...

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" Characterization of the acidic properties of zeolites and their catalytic behavior in the synthesis of MTBE "
Z. S. Seddigi

Document Type	:	Latin Dissertation
Language of Document	:	English
Record Number	:	1113393
Doc. No	:	TLpq230982492
Main Entry	:	Z. S. Seddigi
Title & Author	:	Characterization of the acidic properties of zeolites and their catalytic behavior in the synthesis of MTBE\ Z. S. Seddigi
College	:	King Fahd University of Petroleum and Minerals (Saudi Arabia)
Date	:	1994
student score	:	1994
Degree	:	M.S.
Page No	:	202
Abstract	:	The synthesis of high silica medium acid MFI zeolites in the laboratory was successfully achieved by using the rapid crystallization method. These zeolites with medium acidic strengths are good catalysts for the MTBE synthesis. The synthesized samples were characterized by FTIR, X-ray diffraction technique and thermal analysis. It was found that these catalysts are 100% crystalline. The catalyst to 1 M usd\rm NH\sb4NO\sb3usd solution ratio of 1g: 150 ml, a temperature of 80C and a duration of 1 hour were found as optimum conditions for ion-exchanging process. The modification of the commercial Y zeolite by impregnation with barium oxide was successful. However, the modification of the same catalyst by dealumination requires more investigation in the range of 0.1-0.5 M HCl. Characterization of some commercial, synthesized and modified zeolite catalysts in terms of their acidity was accomplished using: (1) TPD of ammonia, (2) FTIR of adsorbed pyridine and (3) XPS of adsorbed pyridine. It was found that the TPD of ammonia is the most versatile technique in investigating the acidic properties of the different catalysts employed in this study. Three different cells were designed and used for conducting the FTIR study efficiently. The catalytic performance for the MTBE synthesis over some selected catalysts was evaluated. The reaction of isobutene and methanol to produce MTBE was carried over commercial HY zeolite, Ba-modified HY zeolite, commercial Ti-silicalite, commercial HZSM-5 and laboratory synthesized high silica MFI zeolites. The MTBE reaction was studied in a fixed-bed tubular reaction system. Experiments were carried out under atmospheric pressure at various temperatures, space velocity of 32 hr and methanol to isobutene ratio of 2. The temperature was optimized to 100C with the highest percent yield of MTBE.
Subject	:	Chemistry
	:	Pure sciences