Energy issues in the United States are currently receiving a very high priority. There is a strong desire to replace fossil fuels with alternative sources of energy since fuel prices are rising dramatically, and for the harming effect on the environment. Biomass is one of the most promising alternative sources of energy. In this study, hydrothermal liquefaction with alcohol co-solvents was applied on giant miscanthus (Miscanthus giganteus) feedstock. All liquefaction experiments were conducted in 5500 series Parr® reactor. The most important parameters that affect the liquefaction process were studied. The yield of the liquefaction process was determined gravimetrically and the produced bio-oils were characterized. Bio-oil obtained at the optimum conditions was upgraded using different solid acid catalysts and the chemical composition for the upgraded bio-oil was determined. In a new study, the solid acids were added directly during the liquefaction process to produce upgraded bio-oil in one liquefaction/upgrading step.

The use of heterogeneous catalysis is well established in chemical synthesis, energy, and environmental engineering applications. Supported Pt nanoparticles have been widely reported to act as catalysts in a vast number of chemical reactions. In this report, the performance of Pt/ZrO2 nanocatalyst for the decomposition of methanol, ethanol, 2-propanol, and 2-butanol is investigated. The potential of each alcohol for the production of H2 and other relevant products in the presence of a catalyst is studied. All the alcohols studied show some decomposition activity below 200°C which increased with increasing temperature. In all cases, high selectivity towards H2 formation is observed. With the exception of methanol, all alcohol conversion reactions lead to catalyst deactivation at high temperatures (T > 250°C for 2-propanol and 2- butanol, T > 325°C for ethanol) due to carbon poisoning. However, long-term catalyst deactivation can be avoided by optimizing reaction conditions such as operating temperature. In addition, the performance of Pt/γ-Al2O3 is evaluated in the oxidation of 2-propanol. Pt nanoclusters of similar size (~1 nm diameter) but different structure (shape) were found to display distinctively different catalytic properties. All the systems studied achieve high conversion (~ 90%) below 100°C. However, flatter particles display a lower reaction onset temperature, demonstrating superior catalytic performance. Acetone, CO2, and water are generated as products indicating that both partial and complete oxidation are taking place. A number of techniques including AFM, XPS, TEM, HAADF-TEM, XAFS as well as packed-bed reactor experiments were used for sample characterization and evaluation of catalytic performance.

Submitted in fulfilment of the academic requirements for the Masters Degree in Technology: Chemistry, Durban University of Technology,2013. / The thermodynamic properties of binary liquid mixtures using an ionic liquid (IL) with alcohols were determined at different temperatures. The ionic liquid used was 1-butyl-3- methylimidazolium methylsulphate [BMIM]+[MeSO4]-. Densities, speed of sound, and refractive indices for the binary mixtures ([BMIM]+[MeSO4]- + methanol, or 1-propanol, or 2-propanol, or 1-butanol) were experimentally measured over the whole range of composition at T = (298.15, E 303.15, 308.15, and 313.15) K. From the experimental data, excess molar volumes, V m , E , deviations in refractive isentropic compressibilities, κ s , excess isentropic compressibilities, κ S indices, ∆n, and molar refractions, R, were calculated. The excess partial molar volumes were also calculated at T = 298.15 K. For the binary systems, ([BMIM]+[MeSO4]- + methanol, or 1-propanol, or 2-propanol, or E E E 1-butanol) V m and κ S are always negative and V m decrease slightly when the temperature increases. The refractive index deviation at T = (298.15, 303.15, 308.15, and 313.15) K is positive over the whole composition range. The measured negative values for excess molar volume of these mixtures ([BMIM]+[MeSO4]- + methanol, or 1-propanol, or 2-propanol, or 1-butanol) indicate strong ion-dipole interactions and packing between alcohols and IL are present. The Redlich-Kister smoothing polynomial equation was satisfactorily applied for the E E fitting of the V m , κ S , and ∆n data to give the fitting parameters and the root-mean-square deviations. The Lorentz-Lorenz (L-L) equation was also used to correlate the volumetric property and predict the density or refractive index of the binary mixtures of ionic liquid and the organic solvents. The Lorentz-Lorenz approximation gives a higher σ when used to correlate the iiiexcess molar volumes for the mixtures ([BMIM]+[MeSO4]- + methanol, or 1-propanol, or 2-propanol, or 1-butanol). The L-L equation gives good results for the prediction of density and refractive index. The results are discussed in terms of solute-solute, solute-solvent and solvent- solvent interactions. / National Research Foundation

published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy

No description available.

The initial aim of this research project was to oxidise Cr C4 alcohols to their respective aldehydes. However, isolation of these aldehydes was impossible due to their low boiling points. Another problem was the proximity of the boiling points of these aldehydes with the boiling points of solvents used in reactions. As a result, the alcohols investigated in this project were changed to C4-C6 alcohols. Different oxidising reagents are known that oxidise oxidise primary alcohols to aldehydes. Of these, chromium (VI) has been used the most. In this project, Chromium (VI) supported on different inert: inorganic supports was chosen as the oxidising reagent. The first task was therefore to synthesise these supported oxidants. The synthesis of some of these oxidants was lengthy. This is advantage the preparation of supported oxidants. Unsupported oxidants like PCC and chromium trioxide were only used as a basis of comparison to emphasise the usefulness of supported oxidants. Pyridinium chlorochromate was used to oxidise primary alcohols to aldehydes in moderate yields. The reaction was found to be moisture sensitive. The yield and the duration of the reaction was found to be better with the use of molecular sieves. Silica gel-supported pyridinium chromate was also used to oxidise alcohols to aldehydes in good yields. Poly[vinyl(pyridinium chlorochromate)] was used to oxidise I-hexanol and I-pentanol to their respective aldehydes also in good yields. The duration of these reactions ranged from 30 min. to 3 days. During the oxidation of alcohols using silica gel-supported chromium trioxide and diethyI ether/chromium trioxide it was found that the reaction conditions can be changed so that either aldehydes or symmetrical esters were the products. This was achieved by varying the duration of the reaction. Silica gel-supported chromium trioxide resulted in both the aldehydes and esters in good yields while the diethyl iii Aluminium-supported chromium trioxide, kieselguhr-supported chromic acid, alumium silicate-supported chromic acid and alumina-supported pyridinium chlorochromate were used to oxidise primary alcohols to symmetrical and unsymmetrical esters in good to excellent yields. The duration of these reactions varied from 1 hour to 48 hours depending on the conditions employed and the chain length of the reagents. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 1998.

The overall aim of this thesis was to assess the potential of developing specific quantifiable assays of pollutant damage based on changes on the in vivo optical properties of macroalgae, applicable to laboratory and remote systems. The green macroalgae, E. intestinalis, was exposed to selected trace metals (copper and zinc), triazine herbicides (Irgarol 1051 and atrazine) and a series of alcohols (n =1- 9). The algal in vivo spectral properties, measured using a spectrophotometer fitted with an integrating sphere, determined changes due to exposure, and results were compared with established methods, including growth and fluorescence, to assess algal health status. Each pollutant, except zinc, had a significant (P < 0.05) effect on in vivo spectral properties at the range of concentrations used. The results indicated that the technique has potential to identify the algal systems affected by the pollutant, as signatures obtained appeared to indicate whether change was due to structure or pigments. The technique was sensitive, repeatable, and could detect individual pollutants in a copper/Irgarol 1051 mixture. The results were mathematically interpreted to provide ratios, individual wavelengths, sensitivity figures, web diagrams and QSARs to highlight differences between pollutant effect. The QSAR, obtained from Eintestinalis exposed to a series of alcohols, had a R2 value of 0.9682 using in vivo absorptance at 680 nm and Log Kow, which corresponds with published values of 0.97 using ion leakage with the same species. However, the technique of in vivo spectral properties has the advantage of being non-invasive. Samples of E. intestinalis were collected from different field sites and their in vivo spectral responses could be grouped according to potential pollutants to which they had been exposed. In addition, the potential of extending the technique for use in remote sensing is discussed. It was concluded that the technique of monitoring in vivo spectral properties is an appropriate biomonitor to add to the expanding range of current biomonitors.

Thesis advisor: Marc L. Snapper / Chapter 1 Review of methodology developments in the area of selective tosylation of alcohols. Chapter 2 Development of a catalytic enantioselective tosylation of alcohols with an amino-acid-based organocatalyst. / Thesis (MS) — Boston College, 2011. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Chemistry.

No description available.

<p>The major part of this thesis describes the synthesis of enantiopure alcohols and diols by combining ruthenium-catalyzed redox reactions that lead to racemization or epimerization and lipase-catalyzed asymmetric trans-formations in one-pot.</p><p>A mechanistic study of the unexpected facile formation of <i>meso</i>-diacetate products found in enzyme-catalyzed acetylations of alkanediols with <i>Candida antarctica</i> lipase B (CALB) was first performed. By deuterium labeling it was found that the formation of <i>meso</i>-diacetates proceeds via different mechanisms for 2,4-pentanediol and 2,5-hexanediol. Whereas the first reacts via an intramolecular acyl migration, the latter proceeds via a direct, anomalous S-acylation of the alcohol. The acyl migration occurring in the 2,4-pentanediol monoacetate was taken advantage of in asymmetric transformations of substituted 1,3-diols by combining it with a ruthenium-catalyzed epimerization and an enzymatic transesterification using CALB. The in situ coupling of these three processes results in de-epimerization and deracemization of acyclic, unsymmetrical 1,3-diols and constitutes a novel dynamic kinetic asymmetric transformation (DYKAT) concept.</p><p>Racemization of secondary alcohols effected by a new ruthenium complex was combined in one-pot with an enzyme-catalyzed transesterification, leading to a chemoenzymatic dynamic kinetic resolution (DKR) operating at room temperature. Aromatic, aliphatic, heterocyclic and functionalized alcohols were subjected to the procedure. A mechanism for racemization by this ruthenium complex has been proposed and experimental indications for hydrogen transfer within the coordination sphere of ruthenium were found. The same ruthenium catalyst was used for epimerization in DYKAT of 1,2-diols, and a very similar complex was employed in isomerization of allylic alcohols to saturated ketones. The former method is a substrate extension of the above principle applied for DYKAT of 1,3-diols. The combination of a lipase and an organocatalyst was demonstrated by linking a lipase-catalyzed transesterification to a proline-mediated aldol reaction for the production of enantiopure (<i>S</i>)-<i>β</i>-hydroxy ketones and acetylated (<i>R</i>)-aldols.</p>