Thesis (MSc)--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: In this thesis the synthesis of a wide range of model and siloxane functionalized
N-(n-propyl)-1-(2-pyridyl and quinolyl)-imine ligands (L1-L6) are described.
Functionalized ligands (L4-L6) were obtained by the reaction of the pyridyl and quinolyl
aldehydes with 3-aminopropyltriethoxysilane. Model ligands were characterized by
FT-IR and 1H NMR spectroscopy while 13C{1H} NMR spectroscopy was additionally used
for functional ligand characterization. Functionalized complexes of both Pd(II) and Cu(I)
were found to be more thermally stable than their model counterparts. Overall the
model Pd(II) complexes showed a higher thermal stability than the model Cu(I)
complexes.
Ligands (L1-L6) were reacted with either Pd(II) or Cu(I) metal precursors to produce
both the model and functionalized Pd(II) (C1-C6) and Cu(I) (C7-C12) metal complexes.
These metal complexes were all characterized by FT-IR spectroscopy, 1H NMR and
UV/Vis spectroscopy for the model Cu(I) complexes. Functionalized complexes were
additionally characterized with 13C{1H} NMR spectroscopy.
Siloxane functionalized complexes of Pd(II) and Cu(I) were immobilized on MCM-41 and
SBA-15 silica materials to produce heterogenized immobilized catalysts. These
immobilized catalysts were characterized by a wide range of solid state techniques
including: BET nitrogen adsorption/desorption, scanning electron microscopy (SEM),
thermal gravimetric analysis (TGA), ICP-AES, FT-IR spectroscopy, powder XRD and
solid state 13C{1H} NMR spectroscopy. ICP-AES and BET surface analysis showed that
better complex immobilization occurred for SBA-15 supported materials despite SBA-15 having a significantly lower surface area than MCM-41. This higher immobilization was
ascribed to the larger pore sizes of SBA-15 (50 Å) vs. that of MCM-41 (26 Å).
Immobilized catalysts were tested for the oxidation of benzyl alcohol to benzaldehyde.
Immobilization had a positive effect on the catalytic activity of the Pd(II) complexes with
higher conversions being observed for immobilized Pd(II) catalysts when compared to
their model analogues. Overall the MCM-41 immobilized Pd(II) catalysts showed a
higher increase in activity than SBA-15 immobilized catalysts. For Ti-doped supports a
generally higher activity was seen for the Ti-SBA-15 system. The Cu(I) systems
however were not as effective in the oxidation reactions. / AFRIKAANSE OPSOMMING: In hierdie tesis word die sintese van `n wye reeks model sowel as gefunksioneerde
N-(n-propiel)-1-(2-piridiel en kinoliel)-imien ligande (L1-L6) beskryf. Gefunksioneerde
ligande (L4-L6) is gevorm deur die reaksie van piridiel en kinoliel aldehied met
3-amniopropieltriëtoksiesilaan. Model ligande is gekaraktariseer deur FT-IR en 1H KMR
spektroskopie terwyl 13C{1H} KMR spektroskopie addisioneel gebruik is vir die
karaktarisering van die gefunksioneerde ligande.
Ligande (L1-L6) is gereageer met Pd(II) of Cu(I) metaal voorgangers om beide model
sowel as gefunksioneerde Pd(II) (C1-C6) en Cu(I) (C7-C12) metaal komplekse op te
lewer. Hierdie metaal komplekse is almal gekaraktariseer deur FT-IR, 1H KMR en
UV/Vis spektroskopie vir die model Cu(I) komplekse. Gefunksionalseerde komplekse is
addisioneel gekaraktariseer deur gebruik te maak van 13C{1H} KMR spektroskopie. Dit
is gevind dat gefunksionaliseerde komplekse van beide Pd(II) sowel as Cu(I) termies
meer stabiel was as hulle ooreenstemmende model komplekse. Oor die algemeen het
die Pd(II) komplekse hoër termiese stabiliteit as die Cu(I) komplekse getoon.
Siloksaan gefunksioneerde komplekse van Pd(II) en Cu(I) is geimmobiliseer op MCM-41
en SBA-15 silika materiale om heterogene geimmobiliseerde katalisatore op te lewer.
Hierdie geimmobiliseerde katalisatore is gekaraktariseer deur van `n wye reeks vaste
toestand tegnieke gebruik te maak. Hierdie suit in: SEM, TGA, ICP-AES, FT-IR, poeier
XRD en vaste toestand 13C{1H} KMR spektroskopie. ICP-AES en BET oppervlak
analieses het getoon dat beter kompleks immobilisering vir die SBA-15 silika material
plaas gevind het, ondanks die feit dat SBA-15 `n laer oppervlak area beskik. Hierdie hoër graad van immobilisering is toegeskryf aan die groter poriegrootte van SBA-15 (50
Å) teenoor die van MCM-41 (26 Å).
Geimmobiliseerde katalisatore is getoets in die oksidasie van bensielalkohol na
bensaldehied. Dit is gevind dat die immobilisering van die Pd(II) komplekse op die silika
materiaal `n positiewe uitwerking op die aktiwiteit van die katalitiese van die komplekse
gehad het. Die hoogste toename in aktiwiteit is gesien vir geimmobiliseerde Pd(II)
katalisatore wanneer hulle met hul ooreenstemmende model komplekse vergelyk is.
Oor die algemeen is gevind dat MCM-41 geimmobiliseerde Pd(II) katalisatore n hoër
toename in aktiwiteit getoon het as die van SBA-15. Vir die Ti-gedokterde silika
materiale het die Ti-SBA-15 sisteem oor die algemeen `n hoër aktiviteit getoon as die
Ti-MCM-41 sisteem. Die Cu(I) sisteme was egter nie so effektief in oksidasie reaksies
nie.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/6721 |
| Date | 03 1900 |
| Creators | Kotze, Hendrik de Vries |
| Contributors | Mapolie, Selwyn, University of Stellenbosch. Faculty of Engineering. Dept. of Chemistry and Polymer Science. |
| Publisher | Stellenbosch : University of Stellenbosch |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | Unknown |
| Type | Thesis |
Page generated in 0.0036 seconds