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Typescript (photocopy). / Digitized by Kansas Correctional Industries

Molecular dynamics (MD) is a computer simulation of physical movements of atoms and molecules. MD has now been widely used in materials, biochemical and pharmaceutical research. In recent years, zirconium phosphate (ZrP) compounds developed a new type of multi-function mediated porous materials, which the crystalline £\-zirconium phosphate (£\-ZrP) is a cationic layered compounds, with a neat layer structure and easy to design. Cetyl trimethyl ammonium bromide (CTAB) is a cationic surfactant, it¡¦s one kind of ammonium salt of a long carbon chain as hydrophobic groups. Ion exchange can occur with other exchangeable cations. In this study, we first use CTAB inserted into £\-ZrP interlayer to prepare £\-ZrP-CTAB material. Second, we add phenol solution in the system, and use molecular dynamics simulations to observe the solution¡¦s penetration and adsorption. The result shows that pure water can permeate through £\-ZrP CTAB membrane, and pure phenol will be adsorbed by the £\-ZrP-CTAB membrane. If we add phenol solution, the water molecules can pass through the £\-ZrP-CTAB membrane but phenol molecule can¡¦t. It can achieve the effect of separation of the mixed solution. Last we simulate phenolate solution system. The result shows that the number of phenolate molecule enter the membrane is less than phenol molecule in phenol solution. This result is also consistent with the experiments mentioned in the literature.

Crystalline TiO2 nanoparticles were synthesized by hydrolysis of titanium (IV) isopropoxide (TTIP) in the Aerosol OT (AOT)¡Ðcyclohexane microemulsion at controlled temperature. The influence of various reaction conditions, such as mixing energy ( ), [AOT] concentration (W), [TTIP] concentration (R), temperature (T), and aging (t) on the particle size were investigated. The nano-TiO2 particles were characterized for specific surface area (Brunauer-Emmett-Teller, BET) in addition to X-ray diffraction (XRD) and X-ray spectroscopy (XPS) as to determine the particle size, crystalline state, chemical composition, surface charge, and binding energy. The photocatalytic activity was assessed using methylene blue as probe. Results showed that the particle size was in the range from 13.7 to 31.4 nm based on BET measurements. The size of the particle grows with mixing energy until log ( ) = 2.02; further increase in mixing rate caused particle breakup. In micelle solution, the particle size decreased with increase in W. In true solution the particle size increased with W. However, increase in R increased the particle size which reached a maximum value at a critical value of log R = -0.26, then decreased upon further increase in R. The activation energy (Ea) was calculated using Arrenhius plot and a value of -5.96 and -2.17 kJ mol-1 was obtained. Results of particle size analysis from XRD and BET were consistent with each other. Crystalline pattern was proved to be anatase. Furthermore, the photocatalytic activity appeared to optimum with particle size between 22.0-25.1 nm and best crystalline pattern. Titanium dioxide (TiO2) synthesized using the thermal hydrolysis method in our laboratory was used as the photocatalyst in this study to degrade low concentration phenol in aqueous solution. A 150 mL batch reactor was used to carry out the degradation of 0.385 mM phenol solution (pH = 6.5) in room temperature (25 oC) with 0.5 g L-1 TiO2 and irradiated with 10.8 mW cm-2 light intensity for 8 hours. Major intermediate products include hydroquinone (HQ) with the highest quantity followed by catechol (CA), p-benzoquinone (BQ), resorcinol (RES); tri-hydroquinone (THQ) is the secondary intermediate. The by-products consist of 6 organic acids including the six-carbon trans, trans-muconic acid (t,t-MA), the four-carbon maleic acid (MA), the three-carbon propionic acid (PA), the two-carbon oxalic acid (OA) and acetic acid (AA) as well as the one-carbon formic acid (FA). Among these acids, oxalic acid is the most abundant followed by formic acid; the six-carbon t,t-MA is one of the by-products with a lagged formation period. The pathway of intermediate product formation was mathematically calculated and simulated using first-order reaction kinetics models. The reaction rate constants were statistically calculated using functions provided in Microsoft Excel 2003; the simulated results show that the predicted and measured concentrations of the reactant and products in samples collected at various times are consistent.

Thesis (M.S.)--Central Connecticut State University, 1999. / Thesis advisor: James V. Arena, Ph. D. " ... in partial fulfillment of the requirements for the degree of Master of Science in Chemistry." Includes bibliographical references (leaf 48).

Thesis (Ph. D.)--Illinois State University, 1975. / Title from title page screen, viewed Nov. 15, 2004. Dissertation Committee: Anthony E. Liberta (chair), Robert Chasson, Derek McCracken, Fritz Schwalm, David Weber. Includes bibliographical references (leaves 84-90) and abstract. Also available in print.

Thesis (doctoral)--Helsinki University of Technology, 2008. / Includes bibliographical references. Also available on the World Wide Web.

Submitted in fulfilment of the academic requirements for the Degree of Master's in Chemistry, Durban University of Technology, 2017. / Hydrotalcites (HT) and hydrotalcites-like (HTLc) compounds were synthesized by the co-precipitation method under low supersaturation. The synthesized binary Mg-Al hydrotalcites and ternary Cu/Mg-Al hydrotalcite-like compounds were characterized by various physico-chemical techniques such as inductively coupled plasma-optical emission spectroscopy (ICP-OES), powder X-ray diffraction (XRD), Fourier transform- infrared spectroscopy (FT-IR), ultraviolet-visible (UV-VIS) spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and BET surface area analysis. Elemental composition generated from ICP-OES data revealed a value of x in the region of 0.25 to 0.33 for all the compounds except for the MgAl-11 sample which revealed an x value of 0.5 while XRD patterns exhibited characteristic features indicative of an ordered layered material. FT-IR spectra confirmed the presence of characteristic functional groups and interlayer anions. Only Cu2+ which has a d9 configuration was accountable for the bands identified in UV-VIS spectra, whereas both Mg and Al with their d0 electron configurations showed no absorptive bands in the UV-VIS spectra. During thermal treatment by TGA, typical weight loss of Cu-Mg/Al HTLcs with temperature elevation was observed. The SEM images clearly demonstrated that all the Cu-Mg/Al HTLcs retained their characteristically layered structure morphologies. The BET surface area measurements showed no trend, however the surface area decreased with an increase in the copper concentration in some cases. For the heterogeneous hydroxylation of phenol using H2O2 as an oxidant, several reaction parameters such as solvent systems, catalyst amount, temperature, substrate/oxidant ratio, time and solvent volume were investigated. The product stream, monitored by gas chromatography showed that catechol (CAT) and hydroquinone (HQ) were the main products. Non-catalytic (blank) experiments were investigated to determine whether the reactants and the internal standard contributes to the conversion of phenol without the use of a catalyst. All blank reactions showed very low phenol conversions which were less than 1%, whereas the Mg/Al HTs showed low phenol conversions as well. All the Cu-Mg/Al catalysts showed measurable phenol conversion with Cu-Mg/Al-51a giving the highest conversion of 29.9% and a 56 and 44% selectivity towards CAT and HQ, respectively. The Cu-Mg/Al-15b catalyst, which had the lowest copper concentration, showed the lowest phenol conversion of 8.3% with a 55 % CAT selectivity and 45% HQ selectivity. In general, the phenol conversion increased with an increase in copper concentration. This reinforced the hypothesis that copper was the active centre in this reaction, since no measurable conversion was observed with Mg/Al HTs. / M

The objective of this study is to develop a fast curing phenolic formaldehyde (PF) and polymeric diphenyl methane isocyanate (MDI) based hybrid resin system for wood products applications. Various formulas of PF resins were synthesized with different formaldehyde to phenol ratio, sodium hydroxide to phenol and isocyanate group (-NCO) to hydroxyl group (-OH) molar ratios. The shear bonding strength property was used to evaluate and optimize the formulations by appropriate sample preparation. The optimized resins were characterized by rheometer, Fourier transform infrared spectroscopy (FTIR) and other methods. In order to eliminate the influence of hydroxyl groups from water in the PF resin, a frozen dried method was applied to remove the water while keeping PF resin in liquid state. Acetone was used to disperse the hybrid co-polymer to improve the mobility of the mixture of frozen dried PF resins and MDI. An unexpected phenomenon was observed when the two resins were mixed in acetone and a sharp reaction occurred. This led to an assumption that acetone promoted the curing of hybrid resin. The effect of acetone on the curing behavior of hybrid resin was studied by differential scanning calorimetry (DSC), confocal laser scanning microscope (CLSM) and other techniques. It was confirmed that acetone promoted the curing of the co-polymer system. The gel time of hybrid resin with acetone decreases sharply compared to that of pure phenolic resin and original hybrid resin. Acetone also helped the hybrid resin to have better penetration behavior by improving the mobility and this also resulted in less variation of the strength distribution. Finally, lap shear samples were prepared at room temperature curing commercial polyurethane (PU), phenol-resorcinolormaldehyde resin (PRF) and laboratory made hybrid resins based on PF and MDI to compare the shear strength of different resins under different application conditions. The strength reduction of frozen dried PF with acetone/MDI is the lowest in humidity, temperature and humidity-temperature conditions. With just humidity condition, its shear strength reduction is significantly lower than that of any other resins including the solid wood control.