Acid monolayer functionalized iron oxide nanoparticle catalysts

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dc.contributor.author Ikenberry, Myles
dc.date.accessioned 2014-01-27T19:20:02Z
dc.date.available 2014-01-27T19:20:02Z
dc.date.issued 2014-01-27
dc.identifier.uri http://hdl.handle.net/2097/17060
dc.description.abstract Superparamagnetic iron oxide nanoparticle functionalization is an area of intensely active research, with applications across disciplines such as biomedical science and heterogeneous catalysis. This work demonstrates the functionalization of iron oxide nanoparticles with a quasi-monolayer of 11-sulfoundecanoic acid, 10-phosphono-1-decanesulfonic acid, and 11-aminoundecanoic acid. The carboxylic and phosphonic moieties form bonds to the iron oxide particle core, while the sulfonic acid groups face outward where they are available for catalysis. The particles were characterized by thermogravimetric analysis (TGA), transmission electron microscopy (TEM), potentiometric titration, diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), inductively coupled plasma optical emission spectrometry (ICP-OES), X-ray photoelectron spectrometry (XPS), and dynamic light scattering (DLS). The sulfonic acid functionalized particles were used to catalyze the hydrolysis of sucrose at 80˚C and starch at 130˚C, showing a higher activity per acid site than the traditional solid acid catalyst Amberlyst-15, and comparing well against results reported in the literature for sulfonic acid functionalized mesoporous silicas. In sucrose catalysis reactions, the phosphonic-sulfonic nanoparticles (PSNPs) were seen to be incompletely recovered by an external magnetic field, while the carboxylic-sulfonic nanoparticles (CSNPs) showed a trend of increasing activity over the first four recycle runs. Between the two sulfonic ligands, the phosphonates produced a more tightly packed monolayer, which corresponded to a higher sulfonic acid loading, lower agglomeration, lower recoverability through application of an external magnetic field, and higher activity per acid site for the hydrolysis of starch. Functionalizations with 11-aminoundecanoic acid resulted in some amine groups binding to the surfaces of iron oxide nanoparticles. This amine binding is commonly ignored in iron oxide nanoparticle syntheses and functionalizations for biomedical and catalytic applications, affecting understandings of surface charge and other material properties. en_US
dc.description.sponsorship Kansas National Science Foundation's Experimental Program for Stimulating Competitive Research, National Science Foundation, Kansas State Center for Sustainable Energy, en_US
dc.language.iso en_US en_US
dc.publisher Kansas State University en
dc.subject Iron oxide nanoparticle en_US
dc.subject Green chemistry en_US
dc.subject Carbohydrate hydrolysis en_US
dc.subject Solid acid catalyst en_US
dc.title Acid monolayer functionalized iron oxide nanoparticle catalysts en_US
dc.type Dissertation en_US
dc.description.degree Doctor of Philosophy en_US
dc.description.level Doctoral en_US
dc.description.department Department of Chemical Engineering en_US
dc.description.advisor Keith L. Hohn en_US
dc.subject.umi Chemical Engineering (0542) en_US
dc.subject.umi Chemistry (0485) en_US
dc.date.published 2014 en_US
dc.date.graduationmonth May en_US


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