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The mechanism of RAPRENOx reactions - RAPid REduction of Nitrogen Oxides using Isocyanic acid - proposed by Robert A. Perry1 in an attempt to help control the emission of nitrogen oxides pollutant into the atmosphere, has been re-investigated theoretically. The study of reaction mechanisms was carried out using Chemist software2. All mathematically possible elementary steps have been evaluated and the chemically reasonable ones have been considered to propose new sets of reaction mechanisms. Density Functional Theory (B3LYP/6-31 G**) calculations using Gaussian 983 were made in order to study the relative energies of all species and to predict the energy barrier of each elementary step. As a consequence of our study, there are two more sets of reaction mechanisms (in addition to Perry’s mechanism), that could be possible for the propagation step of RAPRENOx process.

This research, focusing mainly on tocotrienols, includes two parts. The first part concerns the uptake and growth inhibition of tocotrienols in PC-3 cells. The second part is a study of the physiochemical properties of Vitamin E. In the cellular study our results suggested that position 5 of chroman head and side-chain are very important in determining the uptake of tocotrienols and growth inhibition of PC-3 cells. The uptake and growth inhibition are not necessarily related to the antioxidant properties of tocotrienols. Of the physiochemical studies, the results suggested that the antioxidant properties of vitamin E are due to the phenolic O-H group. In ethanol solution, each tocotrienol has a higher oxidation potential than its corresponding tocopherol. The oxidation potentials of vitamin E are in the order ofα-form < γform < δ-form. The theoretical calculations show that the side chains of tocotrienols are less ordered than those of tocopherols.

The formation of the tropylium ion, C7H7+, in the mass spectrum of toluene is a chemical process that has been studied extensively in the past. The advances in computational power of personal computers have made the investigation of the pathway to form this ion and its subsequent decomposition feasible at a fairly high level of theory. The calculations that we performed were at the HF/6-31G (d, p) and the B3LYP/6-311++G (2d) levels. This work will show areas of the potential energy surface around the highly symmetric tropylium ion to give a glance of possible mechanisms for its formation and decomposition. Our results have confirmed some of the mechanisms reported in the literature, and in addition new areas are explored in the report.

Several recent studies that have proposed MUSIC models for gibbsite surfaces have purported to achieve a very good fit with potentiometric titration data. However, in order to achieve such results, several significant parameters, such as the number of surface sites, site densities, and pKa values were sometimes re-introduced in the model as fitted parameters, and physically unrealistic modeling assumptions were sometimes used. In addition, recent evidence supports the idea that some of the gibbsite potentiometric titration data from these studies may be unreliable. In order to re-interpret the potentiometric titration data, we used several recently published methods. In order to detect possible problems with estimates of gibbsite basal and edge surface area, we synthesized two gibbsite samples with different aspect ratios and characterized their surface areas using BET, AFM, and computerized image analysis routines. We also estimated pKa values for acid/base reactions at gibbsite surfaces by applying a new bond-valence method to gibbsite (001)-type and (100)-type surface structures based on ab initio calculations. The resulting pKa estimates are not to be taken as precise values due to difficulties and assumptions associated with calculating reasonable ab initio surface structures. Instead, we believe they represent a more reasonable range than has been previously estimated. Using these estimates, we propose an improved MUSIC model for gibbsite, which seems to predict surface adsorption, not perfectly, but within a reasonable range for a number of titration data sets without re-introducing any of our estimated parameters as adjustable parameters. Discrepancies that exist between model predictions and various potentiometric titration data sets are likely due to error associated with potentiometric titrations and pKa predictions.

京都大学 / 新制・課程博士 / 博士(工学) / 甲第24634号 / 工博第5140号 / 新制||工||1982(附属図書館) / 京都大学大学院工学研究科分子工学専攻 / (主査)教授 佐藤 啓文, 教授 佐藤 徹, 教授 松田 建児 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

京都大学 / 新制・課程博士 / 博士(理学) / 甲第24176号 / 理博第4867号 / 新制||理||1696(附属図書館) / 京都大学大学院理学研究科化学専攻 / (主査)准教授 倉重 佑輝, 教授 谷村 吉隆, 教授 吉村 一良 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

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