dc.contributor.author |
Nicolaides, CP
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en_US |
dc.date.accessioned |
2007-03-26T11:52:51Z |
en_US |
dc.date.accessioned |
2007-06-07T10:07:01Z |
|
dc.date.available |
2007-03-26T11:52:51Z |
en_US |
dc.date.available |
2007-06-07T10:07:01Z |
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dc.date.copyright |
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en_US |
dc.date.issued |
1999 |
en_US |
dc.identifier.citation |
Nicolaides, CP. 1999. Novel family of solid acid catalysts: substantially amorphous or partially crystalline zeolitic materials. Applied Catalysis A: General, vol. 185(2), pp 211-217 |
en_US |
dc.identifier.issn |
0926-860X |
en_US |
dc.identifier.uri |
http://hdl.handle.net/10204/2059
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en_US |
dc.identifier.uri |
http://hdl.handle.net/10204/2059
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dc.description.abstract |
Hydrogels, typically used for the synthesis of highly crystalline ZSM-5 samples at 150 degrees C and under autogenous pressure, were subjected to lower hydrothermal synthesis temperatures, i.e., from 25 degrees C to 130 degrees C. XRD analysis of the samples obtained at the various temperatures showed that for synthesis temperatures of up to 70 degrees C, X-ray amorphous aluminosilicates were obtained, whereas treatment at 90 degrees C produced a material exhibiting a 2% XRD crystallinity. Higher synthesis temperatures resulted in higher levels of % crystallinity. Evaluation of the samples as catalysts for the skeletal isomerisation of linear butenes was carried out in a flow reactor at 500 degrees C, MHSV=3 and a butene: nitrogen dilution of 1:10. The results showed that the % conversion of the linear butenes increases and the % selectivity to isobutene decreases with increasing autoclave synthesis temperature, with the highest yield of isobutene (23.4%) being achieved with the 2% XRD crystallinity sample. Higher crystallinities produced considerably lower yields of the branched alkene. The catalytic properties of the 2% XRD crystallinity sample were further evaluated as a function of reaction temperature, 350-500 degrees C, at MHSV=1 and a dilution of 1:10. Highest yield of isobutene was obtained at 500 degrees C and under these reaction conditions, the sample exhibited stable catalytic performance (31% yields) for up to 40 h on-stream. In contrast, under the same reaction conditions, an 86% crystalline ZSM-5 sample gave a 4.9% yield of isobutene. Work on partially crystalline ferrierite-based materials as catalysts for the same reaction was also carried out. |
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dc.format.extent |
132772 bytes |
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dc.format.mimetype |
application/pdf |
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dc.language.iso |
en |
en_US |
dc.publisher |
Elsevier Science BV |
en_US |
dc.rights |
Copyright: 1999 Elsevier Science BV |
en_US |
dc.source |
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en_US |
dc.subject |
Amorphous zeolites Materials |
en_US |
dc.subject |
Crystalline zeolites materials |
en_US |
dc.subject |
ZSM-5 Zeolites |
en_US |
dc.subject |
Ferrierite |
en_US |
dc.subject |
Skeletal isomerization |
en_US |
dc.subject |
Isobutene |
en_US |
dc.subject |
Physical chemistry |
en_US |
dc.subject |
Environmental sciences |
en_US |
dc.title |
Novel family of solid acid catalysts: substantially amorphous or partially crystalline zeolitic materials |
en_US |
dc.type |
Article |
en_US |
dc.identifier.apacitation |
Nicolaides, C. (1999). Novel family of solid acid catalysts: substantially amorphous or partially crystalline zeolitic materials. http://hdl.handle.net/10204/2059 |
en_ZA |
dc.identifier.chicagocitation |
Nicolaides, CP "Novel family of solid acid catalysts: substantially amorphous or partially crystalline zeolitic materials." (1999) http://hdl.handle.net/10204/2059 |
en_ZA |
dc.identifier.vancouvercitation |
Nicolaides C. Novel family of solid acid catalysts: substantially amorphous or partially crystalline zeolitic materials. 1999; http://hdl.handle.net/10204/2059. |
en_ZA |
dc.identifier.ris |
TY - Article
AU - Nicolaides, CP
AB - Hydrogels, typically used for the synthesis of highly crystalline ZSM-5 samples at 150 degrees C and under autogenous pressure, were subjected to lower hydrothermal synthesis temperatures, i.e., from 25 degrees C to 130 degrees C. XRD analysis of the samples obtained at the various temperatures showed that for synthesis temperatures of up to 70 degrees C, X-ray amorphous aluminosilicates were obtained, whereas treatment at 90 degrees C produced a material exhibiting a 2% XRD crystallinity. Higher synthesis temperatures resulted in higher levels of % crystallinity. Evaluation of the samples as catalysts for the skeletal isomerisation of linear butenes was carried out in a flow reactor at 500 degrees C, MHSV=3 and a butene: nitrogen dilution of 1:10. The results showed that the % conversion of the linear butenes increases and the % selectivity to isobutene decreases with increasing autoclave synthesis temperature, with the highest yield of isobutene (23.4%) being achieved with the 2% XRD crystallinity sample. Higher crystallinities produced considerably lower yields of the branched alkene. The catalytic properties of the 2% XRD crystallinity sample were further evaluated as a function of reaction temperature, 350-500 degrees C, at MHSV=1 and a dilution of 1:10. Highest yield of isobutene was obtained at 500 degrees C and under these reaction conditions, the sample exhibited stable catalytic performance (31% yields) for up to 40 h on-stream. In contrast, under the same reaction conditions, an 86% crystalline ZSM-5 sample gave a 4.9% yield of isobutene. Work on partially crystalline ferrierite-based materials as catalysts for the same reaction was also carried out.
DA - 1999
DB - ResearchSpace
DP - CSIR
KW - Amorphous zeolites Materials
KW - Crystalline zeolites materials
KW - ZSM-5 Zeolites
KW - Ferrierite
KW - Skeletal isomerization
KW - Isobutene
KW - Physical chemistry
KW - Environmental sciences
LK - https://researchspace.csir.co.za
PY - 1999
SM - 0926-860X
T1 - Novel family of solid acid catalysts: substantially amorphous or partially crystalline zeolitic materials
TI - Novel family of solid acid catalysts: substantially amorphous or partially crystalline zeolitic materials
UR - http://hdl.handle.net/10204/2059
ER -
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en_ZA |