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Characterization of surface sulfate species on mixed metal oxide catalysts

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TitleInfo
Title
Characterization of surface sulfate species on mixed metal oxide catalysts
SubTitle
insights from spectroscopic studies
Name (type = personal)
NamePart (type = family)
Acharya
NamePart (type = given)
Shreyas
NamePart (type = date)
1993-
DisplayForm
Shreyas Acharya
Role
RoleTerm (authority = RULIB)
author
Name (type = personal)
NamePart (type = family)
Tsilomelekis
NamePart (type = given)
George
DisplayForm
George Tsilomelekis
Affiliation
Advisory Committee
Role
RoleTerm (authority = RULIB)
chair
Name (type = corporate)
NamePart
Rutgers University
Role
RoleTerm (authority = RULIB)
degree grantor
Name (type = corporate)
NamePart
School of Graduate Studies
Role
RoleTerm (authority = RULIB)
school
TypeOfResource
Text
Genre (authority = marcgt)
theses
OriginInfo
DateCreated (qualifier = exact)
2017
DateOther (qualifier = exact); (type = degree)
2017-10
CopyrightDate (encoding = w3cdtf); (qualifier = exact)
2017
Place
PlaceTerm (type = code)
xx
Language
LanguageTerm (authority = ISO639-2b); (type = code)
eng
Abstract (type = abstract)
Solid acid and super acid catalysts are promising alternatives for very important reactions usually catalyzed industrially by homogeneous acid reactions. Sulfated metal oxides are among many examples of solid super acids which work well for acid catalyzed reactions. These catalysts have applications in isomerization, alkylation, acylation and oxidative dehydrogenation reaction. A characteristic example encompasses products from tert-butylation of phenol which have tremendous importance in chemical, petrochemical as well as pharmaceutical industry. In spite of significant amount of work devoted in this area, the catalysts being commercially used have low yields. Hence we channel our efforts in enhancing the productivity of the alkylation of phenol reaction by using sulfated metal oxides as it has shown in our preliminary work improved catalytic activity. In this work, we focus on the preparation and characterization of sulfated mixed metal oxides. Specifically, sulfated-Tin-Zirconium oxides (STZ) are produced by coprecipitation method using hydrated Zirconium Oxychloride(ZrOCl2.8H2O) and Tin Chloride(SnCl4.5H2O) as metal precursors and ammonia as the precipitating agent. Different proportions of hydrous tin and zirconium oxides (molar ratios of 1:10,1:1 and 10:1) are synthesized. Sulfation of the prepared hydrous oxides is performed using wet impregnation method with 1M and 0.5M sulfuric acid solution. Calcination of the prepared sulfate mixed hydroxides follows at 600oC. Our work focuses on the incorporation of vibrational spectroscopic teqniques at the individual steps of the synthesis procedure. To that end, first we utilize Raman spectroscopy to study the speciation of the metal salts precursors in water and at various pH range. The broad spectral envelope is assigned to specific vibational modes of the various species. XRD analysis is done to understand the crystalline phases of the catalyst. Additionally, we study the temperature evolution of the deposited sulfated species by means of in-situ Attenuated Total Reflection (ATR-FTIR) and in-situ Raman spectroscopy using high temperature reaction chamber. The results show that the molecular structure of the surface sulfate species varies significantly with increasing temperature as underscored by the changes of S=O vibrational bands. It was found that the sulfated species getting attached to the catalyst support can majorly be present as bidentate, tridentate and polymeric species and are a function of the temperature as well as the Sn:Zr ratio. Tuning the molecular structure of the sulfated species could potentially alter the acidic properties of the catalysts as indicated by the Lewis/Bronsted acid sites. Lastly, it was found that the crystalline phases of the the regenerated catalyst remain unaffected along with the sulfated groups.
Subject (authority = RUETD)
Topic
Chemical and Biochemical Engineering
Subject (authority = ETD-LCSH)
Topic
Raman spectroscopy
Subject (authority = ETD-LCSH)
Topic
Oxides
RelatedItem (type = host)
TitleInfo
Title
Rutgers University Electronic Theses and Dissertations
Identifier (type = RULIB)
ETD
Identifier
ETD_8424
PhysicalDescription
Form (authority = gmd)
electronic resource
InternetMediaType
application/pdf
InternetMediaType
text/xml
Extent
1 online resource (x, 52 p. : ill.)
Note (type = degree)
M.S.
Note (type = bibliography)
Includes bibliographical references
Note (type = statement of responsibility)
by Shreyas Acharya
RelatedItem (type = host)
TitleInfo
Title
School of Graduate Studies Electronic Theses and Dissertations
Identifier (type = local)
rucore10001600001
Location
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NjNbRU
Identifier (type = doi)
doi:10.7282/T37M0C2X
Genre (authority = ExL-Esploro)
ETD graduate
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Rights

RightsDeclaration (ID = rulibRdec0006)
The author owns the copyright to this work.
RightsHolder (type = personal)
Name
FamilyName
Acharya
GivenName
Shreyas
Role
Copyright Holder
RightsEvent
Type
Permission or license
DateTime (encoding = w3cdtf); (qualifier = exact); (point = start)
2017-09-27 11:58:45
AssociatedEntity
Name
SHREYAS ACHARYA
Role
Copyright holder
Affiliation
Rutgers University. School of Graduate Studies
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Type
License
Name
Author Agreement License
Detail
I hereby grant to the Rutgers University Libraries and to my school the non-exclusive right to archive, reproduce and distribute my thesis or dissertation, in whole or in part, and/or my abstract, in whole or in part, in and from an electronic format, subject to the release date subsequently stipulated in this submittal form and approved by my school. I represent and stipulate that the thesis or dissertation and its abstract are my original work, that they do not infringe or violate any rights of others, and that I make these grants as the sole owner of the rights to my thesis or dissertation and its abstract. I represent that I have obtained written permissions, when necessary, from the owner(s) of each third party copyrighted matter to be included in my thesis or dissertation and will supply copies of such upon request by my school. I acknowledge that RU ETD and my school will not distribute my thesis or dissertation or its abstract if, in their reasonable judgment, they believe all such rights have not been secured. I acknowledge that I retain ownership rights to the copyright of my work. I also retain the right to use all or part of this thesis or dissertation in future works, such as articles or books.
RightsEvent
DateTime (encoding = w3cdtf); (qualifier = exact); (point = start)
2017-10-31
DateTime (encoding = w3cdtf); (qualifier = exact); (point = end)
2019-10-31
Type
Embargo
Detail
Access to this PDF has been restricted at the author's request. It will be publicly available after October 31st, 2019.
Copyright
Status
Copyright protected
Availability
Status
Open
Reason
Permission or license
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2017-09-29T13:27:43
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2017-09-29T13:27:43
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