With the aim of finding alternative reaction media for the synthesis of subvalent main group and transition metal cluster compounds, traditionally made through solid state reactions or in superacidic media, different alternative reaction media have been explored in this work. Room-temperature ionic liquids are amongst the more unconventional reaction media used. The syntheses performed have been aimed at both anionic and cationic cluster and the main tools used for characterization have been different X-ray diffraction and spectroscopic techniques. Selected ionic liquids have along with dichloromethane been shown to work as alternative reaction media for room temperature synthesis of the Bi5[GaCl4]3 salt. The salt containing the subvalent naked bismuth polycation Bi5 3+ was isolated from reduction reactions of BiCl3 in Ga/GaCl3-dichloromethane respectively Ga/GaCl3-ioinc liquid media. Three different classes of ionic liquids based on phosphonium-, imidazolium- and pyrrolidinium- salts have been used in synthesis. Homopolyatomic clusters from the lighter Group 15 element arsenic have also been studied. Solutions from the oxidative and reductive reaction routes of arsenic and AsCl3 in Lewis acidic toluene media were studied by EXAFS spectroscopy. The results were evaluated using molecular dynamics simulations of arsenic clusters. A discussion on how the calculated As4 cluster model relates to the experimental data resulted from this study. In terms of homopolyatomic anionic clusters the [K+(2,2,2-crypt)]2Ge9 2- compound containing the naked Ge9 2- anionic cluster has been isolated. The crystallographic investigation of [K+(2,2,2-crypt)]2Ge9 2- shows Zintl cluster anion Ge9 2- to be tricapped trigonal-prismatic with a symmetry very close to D3h. A chemical bonding analysis reveals two local minima of D3h symmetry and the cluster interaction scheme to be based on highly delocalised bonding. Ligand supported transition metal clusters from tungsten and palladium have also been prepared. Reduction of WCl6 in a reaction mixture of ionic liquid and co-solvent toluene resulted in tritungsten decachloride; W3Cl10(MeCN)3, being formed. Furthermore, palladium sandwich compounds; [Pd2(Ga2Cl7)(C7H8)2], [Pd2(GaCl4)(C9H12)2]∙C9H12 and [Pd2(Ga2Cl7)(C6H5Cl)2] have been prepared using GaCl3-arene reaction media. / <p>QC 20121212</p>

This thesis deals with the development of catalytic oxidation reactions utilizing hydrogen peroxide as terminal oxidant. The main focus has been to find flavin catalysts that are easy to handle and stable to store but still able to perform the desired reaction. A variety of dihydroflavins were prepared and the electrochemical oxidation potentials were measured and compared with their catalytic activity. A flavin catalyst was applied in the sulfoxidation of allylic and vinylic sulfides by H2O2. This transformation was highly chemoselective and the sulfoxides were obtained without formation of other oxidation products. The scope of the reaction was demonstrated by applying the method on substrates with a wide range of functional groups such as a tertiary amine. Another flavin catalyst was immobilized in the ionic liquid [BMIm]PF6 and used for sulfoxidations by H2O2. The chemoselectivity was maintained in this system and the catalyst-ionic liquid system could be recycled several times. Finally two bimetallic catalyst systems for the dihydroxylation of alkenes by H2O2 were immobilized in the ionic liquid. These systems employed either vanadium acetylacetonate VO(acac)2 or methyl trioxorhenium (MTO) as co-catalysts together with the substrate-selective osmium catalyst. Good to excellent yields of the diols were obtained.

This study aims efficient conversion of cotton stalks to cellulosic ethanol through ionic liquid pretreatment and enhanced enzymatic hydrolysis. Among several ionic liquids, EMIMAc exhibited the most striking impact on cotton stalks with respect to the changes in biomass structure and digestibility. Cotton stalks, which were subjected to EMIMAc pretreatment at 10% (w cotton stalks/w EMIMAc) of biomass loading and 150&deg / C for 30 minutes, were found to be 9 times more digestible than untreated cotton stalks. Besides, glucose and ethanol yields, which were based on the cellulose content of untreated cotton stalks, were found as 67% and 66%, respectively. These yields were insufficient regarding efficient conversion of the cellulosic portion of cotton stalks to glucose and ethanol which is linked to the superior solvation capability of EMIMAc towards biomass. In order to enhance aforementioned yields, EMIMAc pretreatment was conducted at 30% of biomass loading. Though lignin extracted was much lower, higher yields were obtained compared to the former case since 96% of cellulose was recovered upon EMIMAc pretreatment and reduced crystallinity was observed for pretreated biomass. Glucose yield was achieved as 84% even at a substrate loading of 15% (w/v). Additionally, 76% of ethanol yield and 3% (v/v) of ethanol titer were obtained upon fermentation. Accordingly, reduction in biomass crystallinity was satisfactory to improve enzymatic accessibility of the biomass. Besides, EMIMAc maintained its effectiveness as a pretreatment agent upon recycling since no change in terms of hydrolysis of pretreated samples was observed upon EMIMAc recycling for three times.

Silylated amines, also known as reversible ionic liquids (RevILs), have been designed and structurally modified by our group for potential use as solvents for CO₂ capture from flue gas. An ideal CO₂ capture ionic liquid should be able to selectively and reversibly capture CO₂ and have tolerance for other components in flue gas, including SO₂, NO₂, and O₂. In this project, we study the reactivity, selectivity, uptake capacity, and reversibility of RevILs in the presence of pure SO₂ and mixed gas streams tosimulate flue gas compositions. Tripropylsilylamine (TPSA), a candidate CO₂ capture RevIL, reacts with pure SO₂ to form an ionic liquid consisting of an ammonium group and a salfamate group, supported by IR and NMR results. The resulting IL with pure SO₂ partially reverses when heated to temperatures of upto 500 C in the TGA. TGA analysis of the ionic liquid formed from a 4 vol% SO₂ in CO₂ mixture indicates a possible reversal temperature in the 86-163 C range.

A novel ionic liquid crystal (ILC) system (C18IMCNBr) with a liquid crystal alignment used as an electrolyte for a dye-sensitized solar cell (DSSC) showed the higher short-circuit current density (Jsc) and the higher light-to-electricity conversion efficiency than the system using the non- alignment liquid crystalline ionic liquid (C18IMCNBr),due to the higher conductivity of liquid crystal alignment. The larger Jsc and efficiency value of liquid crystal alignment supported that the higher conductivity of liquid crystal alignment is attributed to the enhancement of the exchange reaction between iodide species. As a result of formation of the two-dimensional electron conductive pathways organized by the localized I3- and I- at liquid crystal alignment layers, the concentration of polyiodide species exemplified by Im- (m =5,7, ...) was higher in alignment C18IMCNBr. However, in the two-dimensional electron conductive pathways of C18IMCNBr, more collision frequencies between iodide species (I-,I3-, and Im-) could be achieved than that in the three-dimensional space of C18IMCNBr, which could lead to the promotion of the exchange reaction between iodide species, the contribution of a two-dimensional structure of the conductive pathway through the increase of collision frequency between iodide species was proposed.

This study used jatropha oil, waste cooing oil, and soybean oil as the raw materials for investigating effects of catalyst concentration, reaction time, reaction temperature, methanol-to-oil ratio, and catalyst types on biodiesel yield. The authors also heated up the oil to speed up the transesterification and to make the reaction more complete. Jatropha oil, waste cooing oil, and soybean oil were used as the raw materials, and three types of ionic liquid or zwitterionic liquid, [PyrMe][HSO4], [PyrMeBuS][HSO4], and [MorMeA][Br], were added as catalysts for co-catalysis while heating the oil raw materials to create the best operational condition for biodiesel production. For soybean oil used as the raw material, the best catalyzing effect (a 99.4% yield) was achieved by adding [MorMeA][Br] while the reaction time was 6min, reaction temperature was 70 ¢J, and the methanol-to-oil ratio was 9:1. Under the best reaction condition, catalyzing effect was compared between the addition of sulfate-containing ionic liquid and sulfate-containing zwitterionic liquid. The yield of the addition of sulfate-containing ionic liquid and sulfate-containing zwitterionic liquid were 97.2% and 98.7% respectively. It can be found from this study that for increasing biodiesel yield, the addition of zwitterionic liquid for co-catalysis is more effective than the addition of homogeneous ionic liquid. Comparing the best operational condition between jatropha oil and soybean oil, the best yield of jatropha oil and soybean oil was 98.5% and 99.4% respectively, while the concentration of sodium hydroxide was 0.75 wt%, [MorMeA][Br] of 1.00 wt% was added, the methanol-to-oil ratio was 9:1, the reaction time was 6 min, and the reaction temperature was 70¢J. As for disposed cooking oil, the best operational condition rendered a yield of 98.1% when the concentration of sodium hydroxide was 0.75 wt%, [MorMeA][Br] of 1.00 wt% was added, the methanol-to-oil ratio was 9:1, the reaction time was 7 min, and the reaction temperature was 70¢J. For waste cooking oil, because of the containing of impurities from frying, the yield was slightly lower and the reaction time was longer.

The electrochemical behavior of a poly(2,2,6,6-tetramethylpiperidin- 1-oxyl-4-yl methacrylate) (PTMA) cathode in organic radical batteries with lithium bis(trifluoromethylsulfonyl)imide in N-butyl-N-methyl- pyrrolidinium bis(trifluoromethylsulfonyl)imide (LiTFSI/BMPTFSI) ionic liquid electrolytes is investigated. The ionic liquid electrolytes containing a high concentration of the LiTFSI salt have a high polarity, preventing the dissolution of the polyvinylidene fluoride (PVdF) binder and PTMA in the electrolytes. The results of cyclic voltammetry and AC impedance indicate that an increase in the LiTFSI concentration results in a decrease in the impedance of the lithium electrode, which affects the C-rate performance of batteries. The discharge capacity of the PTMA composite electrode in a 0.6 m LiTFSI/BMPTFSI electrolyte is 92.9 mAh g−1 at 1 C; its C-rate performance exhibits a capacity retention, 100 C/1 C, of 88.3%. Moreover, the battery with the 0.6-m LiTFSI/BMPTFSI electrolyte has very good cycle-life performance.

This thesis focuses on the development of new compounds or new processes that are more environmentally friendly and economical than those currently in use. The decomposition of hydrazine, a well established liquid rocket fuel for both the aerospace and defense industries, to the product ammonia is studied. Control of this reaction will allow hydrazine to be used as a propellant for both chemical and electric propulsion. From this a dual stage thruster will be developed that will be more efficient than current systems decreasing the amount of propellant needed and allowing for either a larger mission payload or a longer duration of individual missions. Hydrazine, while beneficial and well established, is also highly toxic, so other work in this thesis focuses on the synthesis of the novel molecule 1,1-dimethyl-2-[2-azidoethyl]hydrazine or DMAEH and its hydrazone intermediate 1,1-dimethyl-2-[2-azidoethyl]hydrazone or De-DMAEH as less toxic hydrazine replacements. Novel "switchable" ionic liquids have been investigated in this research. These are solvents that can change from molecular liquids to ionic liquids and back, simply with the addition or removal of CO₂ from the system. They can be used for a variety of applications, including as solvents for a reaction and separation system. Due to the recyclable nature of these solvents, waste is decreased making their development and implementation both environmentally and economically beneficial. Finally, the grafting reaction of vinyl silanes onto a hydrocarbon backbone is investigated. Fundamental work is being performed to study the graft distribution, selectivity and mechanism by which this reaction occurs. A more thorough understanding of how this reaction proceeds will allow for the development of a more efficient industrial process.

New catalytic synthetic methods in organic chemistry that satisfy increasingly stringent environmental constraints are in great demand by the pharmaceutical and chemical industries. Studies over last 15 years have revealed that activity of enzymes can be increased in organic solvents rather than their natural aqueous environment. Because of their ease of use, high selectivity and environment friendliness, enzymes are enjoying increasing popularity in today's synthesis world. Chapter 1 describes chemo-enzymatic synthesis of various glycolipid analogs. A highly regioselective macrolactonization was achieved using lipase from Candida antarctica as a catalyst. It also describes evaluation of lipases from different source and their efficiency in catalyzing the macrolactonization reaction. These analogs were synthesized using commercially available agriculture based disaccharides (maltose, lactose, cellobiose, melibiose). These glycolipid analogues have potential applications in the cosmetic industry, formulation, food production, and pharmaceutical industry.In Chapter 2, ring opening polymerization of epsilon-caprolactone in ionic liquid, [bmim][PF6] was investigated. A comparative study of ROP in different solvents (toluene, Ionic liquid, and bulk condition) was conducted. Effect of time and enzyme concentration on molecular weight and % yield was investigated. It was concluded that enzymatic ring opening polymerization of epsilon-caprolactone in ionic liquid, [bmim][PF6 ] is a very competitive and environmental friendly way of synthesizing high molecular weight polyesters.

The objectives of the research are to establish the process of obtaining regenerated fibers and films from wood pulp and bagasse pulp with the ionic liquid 1-Butyl-3-methylimidazolium Chloride (BMIMCl) as a solvent; to study the impacts on tensile strength of different spinning parameters; to find the optimal spinning condition, and to obtain regenerated cellulose products with flame retardant properties. Solutions were obtained by dissolving cellulose (wood/bagasse) pulp into the BMIMCl. The solutions were extruded in a dry-jet and wet-spinning method using water as a coagulation bath. The obtained fibers were tested to evaluate the properties such as tensile strength, thermal property, thermal mechanical property, crystal order, and ionic liquid residue in obtained fiber. The orthogonal experiments were designed to find out the strongest affective variable and the optimal condition of the spinning process. The regenerated cellulose films with melamine resin or zinc oxide were obtained. Their flame retardant properties were tested. Cellulose fiber with melamine resin was also obtained. Thermo-gravimetric analyzer (TGA) was used to measure the thermal properties of obtained products, and to calculate their activation energies. Dynamic mechanical analysis (DMA) was used to determine the thermal mechanical properties of obtained fibers. Wide angle X-ray diffraction (WAXD) was used to measure the degree of crystallinity and degree of crystal orientation. The tensile strength was tested by a tensile machine. To evaluate the quantity of ionic liquid residue in the regenerated fibers, the instrumental methods of FT-IR and Mass Spectrometry were applied. Research results indicated increases in the degree of crystallinity and storage modulus under a higher fiber drawing speed. Both regenerated bagasse fibers and regenerated wood fibers had similar thermal properties. However, the regenerated bagasse fibers showed a higher degree of crystallinity and a higher tenacity than the regenerated wood fibers obtained under the same condition. The study also revealed water treatment would be helpful for eliminating the ionic residue in regenerated fibers. It was also found the concentration of cellulose in the BMIMCl solution affected the tensile strength of regenerated fiber mostly. Certain amount of melamine or zinc oxide nanoparticles contained in the cellulose matrix could improve the flame retardant property effectively. / text