Ionic liquids (ILs) were studied as solvents for electrochemical reactions with the intent to devise metallurgical processes for Al, Mg and Ti that are less energy intensive and operate at lower temperatures than current industrial practice. Tetra-alkyl phosphonium ILs are on the low end of the IL cost spectrum and are regarded as understudied compared with imidazolium and pyridinium ILs. They are also known to be more thermally stable. The density, viscosity and conductivity of the phosphonium ILs and metal salt-IL mixtures were measured. The conductivity of the phosphonium ILs tested were found to be roughly an order of magnitude lower than imidazolium ILs; this is attributed to the relatively large cation size and localized charge. Linear density-temperature functions are presented. The viscosity and conductivity temperature relationship was modeled using the Vogel-Tamman-Fulcher (VTF) equation. The electrochemical window of A10341'14,6,6,610 was studied on a Pt substrate over a wide range of A1C13 concentrations using cyclic voltammetry (CV). It was found that the tetra-alkyl phosphonium cation is on the order of 800 mV more electrochemically stable than the 1-ethyl-3-methyl imidazolium (EMI+). Cathodic and anodic polarization of Al in A1C13-[P14,6,6,6]C1 (Xmc13 = 0.67) was studied at temperatures ranging from 347 to 423 K. The Butler-Volmer equation was fitted to the plots by varying the kinetic parameters. The cathodic reaction was found to be diffusion limited and the anodic reaction is limited by passivation at lower temperatures. The overpotential required for electrodissolution of Al was found to be higher than for electrodeposition. Aluminium was electrodeposited using both an electrowinning setup (chlorine evolution anode reaction) and electrorefining setup (Al dissolution anode reaction). The deposits were characterized in terms of morphology, current efficiency and power consumption. A variety of deposit morphologies were observed ranging from smooth, to spherical to dendritic, and in some cases, the IL was occluded in the deposit. The current efficiency and power consumption were negatively impacted by the presence of H2O and HCl present in the as-received ILs and by C12(g) generated by the anode reaction in the case of the electrowinning setup. HC1 was removed by cyclic polarization or corrosion of pure Al, resulting in current efficiencies above 90%. Aluminium was electrodeposited using the electrorefining setup with anode-cathode spacing of 2 mm at power consumption as low as 0.6 kWhr/kg-Al. This is very low compared with industrial Al electrorefining and Al electroplating using the National Bureau of Standards bath, which require 15-18 kWhr/kg-Al and 18 kWhr/kg-Al, respectively. However, due to low solution conductivity the power consumption increases significantly with increased anode-cathode spacing. Titanium tetrachloride was found to be soluble in [P14,6,6,6]Cl and increases the conductivity of the solution. Attempts to reduce the Ti(IV) included corrosion of titanium metal, corrosion of magnesium metal powder and cathodic polarization. Despite a few attempts, the electro-deposition of Ti was not observed. At this point, titanium electrodeposition from phosphonium based ILs does not appear feasible.

Thesis (Ph.D.)--Civil and Environmental Engineering, Georgia Institute of Technology, 2008. / Committee Chair: Löffler, Frank E.; Committee Member: Hughes, Joseph B.; Committee Member: Pennell, Kurt D.; Committee Member: Spain, Jim C.; Committee Member: Taillefert, Martial

Thesis (Ph.D.)--Kent State University, 2009. / Title from PDF t.p. (viewed April 9, 2010). Advisor: Michael Lee. Includes bibliographical references (p. 97-101).

Thesis (Ph. D.)--Catholic University of America, 1934. / Vita.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1969. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Texas at Austin, 1998. / Vita. Includes bibliographical references (leaves 469-477). Available also in a digital version from Dissertation Abstracts.

Thesis (PH. D.)--Catholic University of America, 1934. / Vita.

Οι ζεόλιθοι είναι μικροπορώδεις αργιλοπυριτικές κρυσταλλικές ενώσεις οι οποίες αποτελούνται απο τετράεδρα SiO4 και AlO4 που σχηματίζουν κρυσταλλικά πλέγματα σε μία, δύο ή τρείς διαστάσεις. Εξαιτίας των μοναδικών φυσικοχημικών ιδιοτήτων τους, οι ζεόλιθοι σήμερα χρησιμοποιούνται σε ένα μεγάλο πλήθος εφαρμογών τόσο σε βιομηχανικό όσο και σε εργαστηριακό επίπεδο. Από την άλλη μεριά, ώς ιονικά υγρά ορίζονται οι ιοντικές ενώσεις (άλατα) εκείνες οι οποίες στη θερμοκρασία δωματίου βρίσκονται στην υγρή φάση. Η αμελητέα τάση ατμών, το χαμηλό σημείο τήξεως και οι εξαιρετικές ηλεκτρικές ιδιότητες τους έχουν οδηγήσει στην ολοένα και πιο ευρεία εφαρμογή τους. Ο σκοπός της παρούσας διατριβής είναι η μελέτη του εγκλωβισμού Ιονικών Υγρών σε ζεόλιθο και ο χαρακτηρισμός των παραγόμενων σύνθετων υλικών. Στο πρώτο μέρος της παρούσα διατριβής συνετέθησαν δύο διαφορετικοί ζεόλιθοι και πιο συγκεκριμένα NaY-FAU και BEA με τρείς διαφορετικές αναλογίες Si/Al (250, 50 και 25). Οι παραγόμενοι ζεόλιθοι χαρακτηρίστηκαν με Φασματοσκοπία Περίθλασης Ακτίνων-Χ (XRD), Ηλεκτρονική Μικροσκοπία Σάρωσης (SEM) και φυσιορόφηση Ν2. Στο δεύτερο μέρος της παρούσας διατριβής έγινε μελέτη του εγκλωβισμού ΙΥ σε ζεόλιθο. Πιο συγκεκριμένα μελετήθηκε ο εγκλωβισμός του 1-Η-3-μεθυλιμιδαζολο τριφθορομεθανοσουλφόνυλο ιμιδίου στο ζεόλιθο NaY-FAU. Tα προκύπτοντα σύνθετα υλικά ΙΥ/Ζ τόσο ως προς τις φυσικοχημικές αλλά και ως προς τις ηλεκτροχημικές τους ιδιότητες. Πιο συγκεκριμένα, μελετήθηκαν 2 διαφορετικές μέθοδοι εγκλωβισμού του ΙΥ στο ζεόλιθο NaY-FAU: απευθείας προσθήκη του ΙΥ στον απαερωμένο ζεόλιθο (Μέθοδος 1) και με διάλυση αρχικά του ΙΥ σε MeOH και προσθήκη του ζεόλιθου στο διάλυμα (Μέθοδος 2) και μελετήθηκε η επίδραση της αρχική αναλογία ΙΥ/Ζ και της επίδρασης της διάρκειας της εκχύλισης Soxhlet στη ποσότητα του ΙΥ που παραμένει εγκλωβισμένο και στη δομή του τελικού προϊόντος. Τέλος τα προκύπτοντα συστήματα ΙΥ/Ζ χαρακτηρίστηκαν ως προς την ιοντική τους αγωγιμότητα με Φασματοσκοπίa Σύνθετης Αντίστασης (Α. C. Impedance Spectroscopy). / Zeolites are microporous crystalline compounds that are cosntituted by SiO4 and AlO4 tetrahedra thus forming crystalline structures in one, two or three dimensions. Due to their unique physicochemical properties zeolites are widely used in industrial and laboratory applications. On the other hand, Ionic Liquids are liquids that are liquids at room temperature. Their negligible vapour pressure, the low melting point and their unique electrochemical properties have caused their extensive use in different applications. The scope of this thesis is to study the encapsulation of Ionic Liquids into zeolite structure and the characterization of the obtained composite materials. The first part presents the synthesis and characterization of two different zeolites: NaY-FAU and BEA with three different Si/Al ratio (250, 50 and 25). The obtained zeolites were characterized using X-Ray Diffraction Spectroscopy, Scanning Electron Microscopy, N2 physisorption and Thermogravimetric Analysis. In the second part, the encapsulation of 1-H-3-methylimidazolium bis(trifluoromethane sulfonyl) imide into NaY-FAU was studied. The obtained composite materials were characterized in both physicochemical and electrochemical terms. Thus, two different encapsulation methods were tested: the first on with direct addition of the ionic liquid to the zeolite (Method 1) or by preparation of a Ionic Liquid/Methanol solution and addition of the zeolite. The initial weight ratio and the duration of Soxhlet extraction influence on the properties of the final composite material were studied. Finally, the electrochemical properties of the obtained composite materials were evaluated using A. C. Impedance Spectroscopy measurements.

A systematic study of the excess thermodynamic properties of two-ring compounds and n-alkanes was conducted. The excess enthalpies were determined at 288,15 K and 298,15 K by using a flow microcalorimetric technique. The excess volumes of tetralin and cycloalkanes, and tetralin and --alkans at 288,15 K and 298,15 K were determined by using a vibrating tube densitometer. The results showed trends relating to the size and shape of the n-alkane and cycloalkan molecules. The theory developed by Flory was applied to the decalin + cycloalkane and + n-alkane systems and this gave qualitative predictions of the excess enthalpies from the excess volumes and vice versa. / KMBT_363 / Adobe Acrobat 9.53 Paper Capture Plug-in

abstract: Structural details of phosphonic acid functionalized nanomaterials and protic ionic liquids (PILs) were characterized using nuclear magnetic resonance (NMR) spectroscopy. It is well known that ligands play a critical role in the synthesis and properties of nanomaterials. Therefore, elucidating the details of ligand-surface and ligand-ligand interactions is crucial to understanding nanomaterial systems more completely. In an effort to further the understanding of ligand-surface interactions, a combination of multi-nuclear (1H, 29Si, 31P) and multi-dimensional solid-state NMR techniques were utilized to characterize the phosphonic acid functionalization of fumed silica nanoparticles using methyl phosphonic acid (MPA) and phenyl phosphonic acid (PPA). Quantitative 31P MAS solid-state NMR measurements indicate that ligands favor a monodentate binding mode. Furthermore, 1H-1H single quantum-double quantum (SQ-DQ) back-to-back (BABA) 2D NMR spectra of silica functionalized with MPA and PPA indicate that the MPA and PPA are within 4.2±0.2 Å on the surface of the nanomaterial. The ligand capping of phosphonic acid (PA) functionalized CdSe/ZnS core-shell quantum dots (QDs) was investigated with a combination of ligand exchange, solution and solid-state 31P NMR spectroscopy. In order to quantify the ligand populations on the surface of the QDs, ligand exchange facilitated by PPA resulted in the displacement of the PAs, and allowed for quantification of the free ligands using 31P liquid state NMR. In addition to characterizing nanomaterials, the ionicity and transport properties of a series of diethylmethylamine (DEMA) based protic ionic liquids (PILs) were characterized, principally utilizing NMR. Gas phase proton affinity was shown to be a better predictor for the extent of proton transfer, and in turn the ionicity of the PIL, than using ∆pKa. Furthermore, pulsed field gradient (PFG) NMR was used to determine that the exchangeable proton diffuses with the cation or the anion based on the strength of the acid used to generate the PILs. / Dissertation/Thesis / Doctoral Dissertation Chemistry 2015