TThe disruption of the aluminosilioate crystal lattice by aqueous fluoride solutions has been studied, The effect of reaction time, fluoride concentration, pH, and temperature on the reaction have been investigated« The stoichiometric exchange of hydroxyls by fluoride ions in kaolinite and muscovite at pH 7 below? was extremely doubtful., Disruption of the aluminosil ate crystallattice was thought t o be the predominant reaction over the acid pH range• Fluoride ions were found t react preferentially with the aluminium in the cry s tallattice to form AlP especially at the high e r temperature w

Abstract Lignins have polyphenolic structures, making them candidates to replace phenols and polyphenols in polymers. Lignins are highly recalcitrant, making their refining challenging, requiring harsh temperatures and pressures. Lignins could be partially modified under milder conditions for their use in biopolymers. The main purpose of this research was to upgrade Indulin AT, a kraft pine lignin, to enhance its properties. The first part of this thesis dealt with formic acid aided pressurized hot water extraction (FAPHWE) of hemicelluloses from birch hardwood as the first step in separating the components of a lignocellulosic feedstock (LCF). More than half of the hemicelluloses were extracted as hydrolysis products, while keeping the cellulose hydrolysis products in the extract under 5% and the lignin under 3%. In the second part of this work, a method to determine the amount of phenolic hydroxyl groups (OHph) in lignins was assessed. The Δε IDUS method was found to be useful for comparing the OHph of pine kraft and birch milox lignins, albeit not as precise as carbon-13 nuclear magnetic resonance spectroscopy (13C-NMR). The third part of this thesis explored the tuning of the molar mass (MM) and OHph of Indulin AT by aqueous ethanol fractionation. The results showed that a higher water content favored the extraction of fractions with low MM and low OHph. A high ethanol content favored the extraction of fractions with medium MM and high OHph. A 50–60 wt% ethanol content allowed for near complete solubilization of Indulin AT, which could be beneficial for a single-phase chemical reaction. The fourth part of this research dealt with the depolymerization of Indulin AT in an ethanol-water solvent with formic acid as hydrogen donor. The properties of interest were MM, polydispersity (PDI), OHph, and formaldehyde uptake capability (FUC). The results of the reaction were affected predominantly by temperature. Higher temperatures led to lower MM and PDI, and higher OHph and FUC. The results of this thesis suggest that, in a biorefinery, the first step before delignification of an LCF could be FAPHWE. It was found that the properties of Indulin AT (OHph, FUC, and MM) could be enhanced by chemical depolymerization and physical fractionation. Modified lignins with higher OHph and FUC could be utilized in biopolymer applications such as phenolic resins and polyurethanes. / Tiivistelmä Ligniini on rakenteeltaan polyfenoli, mikä tekee siitä mahdollisen fenolien korvaajan polyfenolien valmistuksessa. Ligniinin rakenne on hyvin kestävä, mikä tekee sen jalostuksesta haastavaa vaatien usein korkean lämpötilan ja paineen käyttöä. Tästä huolimatta ligniiniä voidaan tietyssä määrin muokata miedommissa olosuhteissa, mikä lisää sen käyttökelpoisuutta biopolymeerien raaka-aineena. Tämän tutkimuksen tarkoitus oli jalostaa Indulin AT -kraft ligniiniä siten, että sen ominaisuudet paranevat. Aluksi väitöstyössä tarkasteltiin puun hemiselluloosan muurahaishappokatalysoidun kuumavesiuutton soveltuvuutta lignoselluloosaraaka-aineiden fraktioinnin ensimmäiseksi vaiheeksi. Yli puolet hemiselluloosasta voitiin uuttaa monosakkarideiksi samalla, kun selluloosasta uuttui alle 5 % ja ligniinistä alle 3 %. Seuraavaksi arvioitiin fenolisten hydroksyyliryhmien määritysmenetelmää. Δε IDUS metodin havaittiin olevan hyödyllinen ainakin sulfaattimenetelmän havupuuligniinien ja Milox-prosessin koivuligniininäytteiden vertailussa, vaikkakaan se ei ole yhtä tarkka kuin ydinmagneettiseen resonanssispektroskopiaan (NMR) perustuva analyysi. Tämän jälkeen tutkittiin mahdollisuuksia tuottaa etanoli-vesiliuosfraktioinnilla jakeita, joissa ligniinillä on haluttu molekyylikoko ja fenolisten hydroksyyliryhmien pitoisuus. Tulokset näyttivät, että korkea vesipitoisuus suosii pienen molekyylikoon ja matalan OHph -pitoisuuden sisältäviä jakeiden uuttumista. Korkea etanolipitoisuus suosii keskikokoisen molekyylikoon jaetta, jossa ligniinillä on korkea OHph -pitoisuus. 50–60 m-% etanolipitoisuudessa Indulin AT liukenee lähes täydellisesti, mikä voi olla edullista kemiallisten reaktioiden toteuttamiseen yhdessä faasissa. Lopuksi tutkimuksessa tarkasteltiin ligniinin osittaista depolymerisointia etanoli-vesiliottimessa muurahaishapon toimiessa vetylähteenä. Tarkasteltavat tuotteen ominaisuudet olivat molekyylikoko, polydispersiteetti, fenolisten hydroksyyliryhmien määrä ja formaldehydin sitomiskapasiteetti. Lämpötilan havaittiin olevan merkittävin depolymerisointireaktioon vaikuttava tekijä. Korkea lämpötila johtaa pienempään molekyylikokoon ja kapeampaan molekyylikokojakaumaan sekä suurempaan hydroksyyliryhmien määrään ja formaldehydin sitomiskykyyn. Tämän työn tulokset viittaavat siihen, että hemiselluloosan vesiuutto happamissa olosuhteissa voi olla biojalostamon ensimmäinen vaihe, ennen delignifiointia. Lisäksi havaittiin, että ligniinin ominaisuuksia voidaan muokata kemiallisella depolymerisoinnilla ja fysikaalisella fraktioinnilla. Korkeamman hydroksyyliryhmäpitoisuuden ja formaldehydin sitomiskyvyn muokattuja ligniinejä voidaan hyödyntää biopolymeerisovellutuksissa, kuten fenolisissa hartseissa ja polyuretaaneissa.

Die grundlegenden Aspekte chemischer Reaktionen auf Oberflächen können anhand von geeigneten Modelsystemen unter Vakuumbedingungen untersucht werden. Siliciumdioxid (SiO2) als wichtiges Material für hochmoderne Technologieanwendungen in der Mikroelektronik, Photonik und Katalyse, war Gegenstand zahlreicher Studien, um die Beziehungen zwischen der atomaren Struktur und funktionalen Eigenschaften von Silizium-basierten Materialien zu erklären. Diese Arbeit untersucht die Wechselwirkung von Gasen mit epitaktisch gewachsenen Silikat-Dünnschichten auf einem Ru(0001) Einkristall. Unter Verwendung von Infrarot-Reflexions-Absorptions-Spektroskopie (IRAS) und temperaturprogrammierter Desorptionspektroskopie (TPD) konnten die Hydroxy-Spezies auf reinen Silikatfilmen als isolierte Silanole (Si-OH) identifiziert werden. Isotopenexperimente haben gezeigt, dass sich thermisch stabile Oberflächenhydroxylate hauptsächlich aus der Adsorption von Wassermolekülen bilden. Ein Austausch der Silanole mit Sauerstoffatomen im Kristallgitter während des Dehydroxylierungsprozesses wurde nicht beobachtet. Durch die Adsorption von Gasen wie CO, H2 und O2 bei erhöhtem Druck, lässt sich auf komplexere Prozesse schließen. Dies beinhaltet Gastransport durch Poren im Film, was mit strukturellen Defekten in dem Silikatfilm verbunden ist, sowie nachfolgende Adsorption und Diffusion auf dem unterliegenden Ru(0001)-Substrat. Während der Einlagerung der Moleküle in die Silikatschicht bleibt der Oxidfilm auch unter hohem Druck (~ 10 mbar) sowie hoher Temperatur (~900 K) intakt. Solch ein Hybridsystem, welches eine robuste Siliciumdioxidmembran mit einem sich darunter befindlichen, chemisch aktiven Metall kombiniert, könnte ein interessantes Materialsystem für technische Anwendungen darstellen, insbesondere zur Herstellung von Katalysatoren und Sensoren sowie für Korrosionsanwendungen. / The fundamental aspects of the chemical reactions at surfaces can be elucidated by using well-defined model systems under the controlled conditions provided by vacuum-based techniques. Silicon dioxide (SiO2) as one of the crucial materials in modern technological applications, including microelectronics, photonics, and catalysis, has been subjected to numerous studies in order to rationalize relationships between the atomic structure and functional properties of silica-based materials. This work marks the attempt to understand interaction of ambient gases with a well-ordered, ultrathin silicate film grown on a Ru(0001) substrate. Using infrared reflection absorption spectroscopy (IRAS) and temperature programmed desorption (TPD), hydroxo species, primarily in the form of isolated silanols (Si-OH), were identified on pristine silicate films. Isotopic experiments demonstrated that surface hydroxyls form primarily from the water molecules. Silanols do not undergo scrambling with the lattice oxygen atoms upon dehydroxylation. Steps on a silicate sheet and/or “holes” in these ultrathin films are proposed as active sites for hydroxylation. Adsorption of gases such as CO, H2 and O2 at elevated pressures revealed a more complex behavior. It involves gas transport through the pores, associated with structural defects in the silicate film, subsequent adsorption, and diffusion across the Ru(0001) surface underneath. During this intercalation, the silicate film stays intact even under high pressure (~10 mbar) and high temperature conditions (~900 K). The silicate layer does however strongly passivate the Ru surface towards RuO2(110) formation that readily occurs on bare Ru(0001) under the same conditions. Such a hybrid system, which combines a robust silica “membrane” and a chemically active metal underneath, could become an interesting material for technological applications, in particular in catalysis, sensors and anti-corrosion applications.

With the increasing importance of hand-held devices with touch displays, the need for flat panel displays (FPDs) will likely increase in the future. Glass is the most important substrate for FPD manufacturing, where both its bulk and surface properties are critical for its performance. Many properties of the glass used in FPDs are controlled by its surface chemistry. Surface hydroxyls are the most important functional groups on a glass surface, which control processes that occurs on oxide surfaces, including wetting, adhesion, electrostatic charging and discharge, and the rate of contamination. In this dissertation, I present a new approach for determining surface silanol densities on planar surfaces. This methodology consists of tagging surface silanols using atomic layer deposition (ALD) followed by low energy ion scattering (LEIS) analysis of the tags. The LEIS signal is limited to the outermost atomic layer, i.e., LEIS is an extremely surface sensitive technique. Quantification in LEIS is straightforward in the presence of suitable reference materials. An essential part of any LEIS measurement is the preparation and characterization of the sample and appropriate reference materials that best represent the samples. My tag-and-count method was applied to chemically and thermally treated fused silica. In this work, I determined the silanol density of a fully hydroxylated fused silica surface to be 4.67 OH/nm2. This value agrees with the literature value for high surface area silica powder. My methodology should be important in future glass studies. Surface Science Spectra (SSS) is an important, peer-reviewed database of spectra from surfaces. Recently, SSS has been expanding to accept spectra from new surface techniques. I created the first SSS submission form for LEIS spectra (see appendix 5), and used it to create the first SSS LEIS paper (on CaF2 and Au reference materials, see chapter 3). I also show LEIS reference spectra for ZnO, and copper in the appendix 1. The rest of my dissertation focuses on my chemometrics/informatics and data analysis work. For example, I showed the performance and capabilities of a series of summary statistics as new tools for unsupervised exploratory data analysis (EDA) (see chapter 4). Unsupervised EDA is often the first step in understanding complex data sets because it can group, and even classify, samples according to their spectral similarities and differences. Pattern recognition entropy (PRE) and other summary statistics are direct methods for analyzing data - they are not factor-based approaches like principal component analysis (PCA) or multivariate curve resolution (MCR). I show that, in general, PRE outperforms the other summary statistics, especially in image analysis, although I recommend a suite of summary statistics be used in exploring complex data sets. In addition, I introduce the concept of divided spectrum-PRE (DS-PRE) as a new EDA method and use it to analyze multiple data sets. DS-PRE increases the discrimination power of PRE. I have also prepared a guide that discusses the vital aspects and considerations for chemometrics/informatics analyses of XPS data along with specific EDA tools that can be used to probe XPS data sets, including PRE, PCA, MCR, and cluster analysis (see chapter 5). I emphasize the importance of an initial evaluation/plotting of raw data, data preprocessing, returning to the original data after a chemometrics/informatics analysis, and determining the number of abstract factors to keep in an analysis, including reconstructing the data using PCA. In my thesis, I also show the analysis of commercial automotive lubricant oils (ALOs) with various chemometrics techniques (see chapter 6). Using these methods, the ALO samples were readily differentiated according to their American Petroleum Institute (API) classification and base oil types: mineral, semi-synthetic, and synthetic.