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dc.contributor.advisorLangner, E. H. G
dc.contributor.authorTsai, Chih-Wei
dc.date.accessioned2017-07-03T09:39:12Z
dc.date.available2017-07-03T09:39:12Z
dc.date.issued2017
dc.identifier.urihttp://hdl.handle.net/11660/6444
dc.description.abstractEnglish: Zeolitic Imidazolate Framework-8 nanoparticles (nZIF-8) were successfully synthesized during isothermal benchtop reactions, with different reagent concentrations in methanol. At an optimal concentration, an average particle size of 22 nm was achieved for nZIF-81500 with an external surface area of 320 m2 g-1. Addition of triethylamine (TEA) in different molar ratios during synthesis, increased the yield of nZIF-8 from 40 to 85 %. Particle sizes decreased to 16 nm at high TEA concentrations. Time resolved Solvent Assisted Ligand Exchange (SALE) of nZIF-8 with 2-mercaptobenzimidazole, 2-aminobenzimidazole, 2-phenylimidazole and presynthetic modified benzimidazole-thioesters, resulted in a ~13% exchange of the 2-methylimidazolate linkers of nZIF-8. Following an identical SALE procedure, the exchange with imidazole and 2-nitroimidazole, both without any attached benzene rings, reached a maximum exchange of 86 and 66 %, resulting in new zni and frl topologies respectively. All the SALE processes gave particle sizes below 100 nm, except when 2-mercaptobenzimidazole and 2-nitroimidazole were used. All nZIF-8 materials with SOD topologies remained microporous throughout the SALE process. Four different post synthetic modification (PSM) techniques were developed for aminoand ester functionalised nZIF-8 particles. PSM of lithiated SALEM-2 with (PPh3)2PdCl2, gave a 1.2 wt % Pd content, with an improved BET surface area (100 m2 g-1 larger). An iron content of 8.3 wt % was achieved via amidation of amino functionalised nZIF-8 with ferrocenecarboxylic acid. Sebacoyl chloride and polyacrylic acid were successfully anchored to the surface of amino functionalised nZIF-8. The SALE products of nZIF-8 were screened for catalysis of the Knoevenagel condensation between ferrocenecarboxaldehyde and malononitrile. Amine-containing nZIF-8 gave a lower TOF than nZIF-81500, suggesting a different catalytic pathway via an imine route. CO2 adsorption of nZIF-8 was doubled to 77 cm3 g-1, after SALE with imidazole derivatives containing NO2 and SH electron withdrawing groups. H2 uptake of all nZIF-8 derivatives was on par with the Chahine rule, with SALEM-216h-Pd adsorbing 3.07 wt % of H2 at 77 K.en_ZA
dc.description.abstractAfrikaans: Zeolitiese Imidasolaat Netwerk-8 nanodeeltjies (nZIF-8) is suksesvol gesintetiseer tydens isotermiese mengreaksies, met verskillende reagenskonsentrasies in metanol. By ‘n optimale konsentrasie is ‛n gemiddelde deeltjiegrootte van 22 nm vir nZIF-81500 verkry, met ‛n eksterne oppervlakarea van 320 m2 g-1. Byvoeging van trietielamien (TEA) in verskillende molverhoudings tydens sintese, het die opbrengs van nZIF-8 van 40 na 85% verhoog. Die deeltjiegrootte het afgeneem tot 16 nm by hoë TEA konsentrasies. Tydsveranderlike, oplosmiddelgesteunde liganduitruiling (SALE) van nZIF-8 met 2-merkaptobensimidasool, 2-aminobensimidasool, 2-fenielimidasool en pre-sinteties gemodifiseerde bensimidasool-tioësters, het ‛n ~13 % uitruiling van die 2-metielimidasool skakels van nZIF-8 tot gevolg gehad. Tydens ‘n identiese SALE proses, het die liganduitruiling met imidasool en 2-nitroimidasool, beide sonder enige aangehegde benseenringe, ‘n maksimum uitruiling van 86 en 66 % bereik, met nuwe zni en frl topologieë onderskeidelik. Al die SALE prosesse het deeltjiegroottes onder 100 nm tot gevolg gehad, buiten wanneer 2- merkaptobensimidasool en 2-nitroimidasool gebruik is. Alle nZIF-8 materiale met SOD topologieë het regdeur die SALE proses mikroporeus gebly. Vier verskillende na-sintese modifikasietegnieke (PSM) is ontwikkel vir amino- en estergefunksionaliseerde nZIF-8 deeltjies. PSM van gelitieerde SALEM-2 met (PPh3)2PDCl2, het `n 1.2 wt % Pd inhoud, met `n verbeterde BET oppervlak area (100 m2 g-1 groter) tot gevolg gehad. `n Ysterinhoud van 8.3 wt % is bereik via amidasie van die amino-gefunksionaliseerde nZIF-8 met ferroseenkarboksielsuur. Sebakoïelchloried en poli-akrielsuur is suksesvol geanker aan die oppervlakte van aminogefunksionaliseerde nZIF-8. Die SALE produkte van nZIF-8 is ondersoek as kataliste vir die Knoevenagel kondensasie tussen ferroseenkarboksaldehied en malonnitriel. Amienbevattende nZIF-8 het `n laer TOF as nZIF- 81500 getoon, wat op `n ander katalitiese roete, via `n imien, gedui het. CO2 adsorpsie van nZIF-8 het verdubbel tot 77 cm3 g-1, na SALE met imidasool derivate wat NO2 en SH elektronontrekkende groepe bevat. H2 opname van alle nZIF-8 derivate het die Chahine reël gevolg, met SALEM-216h-Pd wat 3.07 wt % H2 by 77 K geabsorbeer het.af
dc.description.sponsorshipNational Research Foundation (NRF)en_ZA
dc.language.isoenen_ZA
dc.publisherUniversity of the Free Stateen_ZA
dc.subjectZIF-8en_ZA
dc.subjectNanoparticlesen_ZA
dc.subjectParticle sizeen_ZA
dc.subjectSurface areaen_ZA
dc.subjectSolvent assisted ligand exchangeen_ZA
dc.subjectPost synthetic modificationen_ZA
dc.subjectFerroceneen_ZA
dc.subjectGas storageen_ZA
dc.subjectHeterogeneous catalysisen_ZA
dc.subjectKnoevenagel condensationen_ZA
dc.subjectThesis (Ph.D. (Chemistry))--University of the Free State, 2017en_ZA
dc.titleModification of nano-sized zinc zeolitic 2-methylimidazolate frameworks (zif-8) by solvent assisted ligand exchange and post-sythetic modification to enhance functionality towards catalysis, gas storage and drug deliveryen_ZA
dc.typeThesisen_ZA
dc.rights.holderUniversity of the Free Stateen_ZA


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