Chlorination of 2-methyl-2-aryloxypropanoic acids with aqueous hypochlorous acid gives spiro chloro adducts in moderate to high yields. In chlorination of 2-methyl-2-(2-methylphenoxy)propanoic acids, 1,2-adducts are formed, while in the case of 2-methyl-2-(4-methylphenoxy)propanoic acids, 1,4-adducts are obtained. In addition to the spiro adducts, 2-methyl-2-(4-chlorophenoxy)propanoic acids in the former case, and 2-methyl-2-(2-chlorophenoxy)propanoic acids in the latter case are formed, respectively. No 6-chlorosubstituted products are detected on chlorination of any of the substrates. Chlorination of 2-methyl-2-(2,4-dimethylphenoxy)propanoic acid affords only the 1,4-adduct. However, chlorination of 2-methyl-2-(5-chloro-2,4-dimethylphenoxy)propanoic acid gives both the 1,2- and the 1,4-adduct. 2-Methyl-2-(3,5-di-t-butylphenoxyl)propanoic acid on chlorination yields the diastereomeric secondary chloro adduct, 8-chloro-7,9-di-t-butyl-3,3-dimethyl-1,4-dioxaspiro (4,5) deca-6,9-dien-2-one. Under neutral and non-polar conditions, most of the 1,2-adducts undergo a thermal rearrangement of the chlorine which is shown to be a (1,5) sigmatropic chlorine shift. The rearrangement rates are highly dependent on the nature of the substituents in the diene systems. Under acidic and non-nucleophilic conditions, most of the 1,4-adducts undergo an intramolecular 1,2 chlorine shift followed by aromatization to give the 3-chloro-substituted products. For the dienes in which the 3-position is originally substituted, successive 1,2 chlorine migrations and/or side chain substitution are observed. On the other hand, the 1,2-adducts under similar reaction conditions undergo an intermolecular 1,4 chlorine shift to give the 5-chlorosubstituted products. In the case that the 5-position is substituted by a methyl group, side chain substitution at the 5-methyl takes place. In the presence of added base, solvolyses of the 1,4-adducts in methanol affords simple solvolysis products and/or 1,2 carboxyl rearranged products. The kinetic studies of the solvolyses of the 1,4-adducts have been carried out. The results reveal the substituent effects on both the simple solvolysis displacement and the rearrangement reactions. / Graduate

Abstract Washing during kraft pulping can be divided into two separate areas each with its own distinct features: namely brownstock washing and washing in bleaching. Research interest has so far concentrated mostly on investigating brownstock washing and factors affecting its efficiency. Pulp washing in bleaching, however, has been practically neglected. The basic phenomena are the same as in brownstock washing, but there are differences which have not been taken into consideration to a sufficient extent. This less explored area is the focus of this research. In this thesis, it is shown that brownstock washing and pulp washing between bleaching stages are distinct areas with their own specific features. They differ for example in terms of the composition and molecular size of the impurities in the pulp suspension. Various process conditions, pH, temperature and so on cause further differences between washing in bleaching and brownstock washing. The removal of specific compounds can be clearly affected by the appropriate selection of wash liquor. It is shown that the dynamic behaviour during washing is different for different compounds and depends on the properties of the wash water. The key element is to find the most harmful compounds in specific positions in bleaching and on the basis of that finding, to determine the most suitable wash liquor system. Chemical oxygen demand (COD) is a widely used method for evaluating the washing result, but as a collective measurement variable it does not describe the actual compounds that cause the "loss" of bleaching chemicals. Studies have shown that many compounds contribute to COD load but ultimately most of them have no real effect on the bleaching result. A suggestion for more precise definition of wash loss is offered than COD.

The reaction between o-phenylenediamine and 2,3-dichloromaleic anhydride has been probed and found to give 2,3-dichloropyrrolo[1,2-a]- benzimidazol-1-one as the major product. Chlorine substitution in 2,3-dichloropyrrolo[1,2-a]benzimidazol-1-one by added benzylthiol occurs in the presence of pyridine to provide the corresponding monosulfide and disulfide derivatives. The first benzylthiol ligand undergoes reaction at the C-3 position of the five-membered pyrrolo-1-one ring, with the addition of the second benzylthiol ligand occurring at the remaining chlorine-substituted carbon. The mono- and disulfide derivatives have been isolated and characterized in solution by NMR, IR, and UV-vis spectroscopies, and the solid-state structure of 2,3-di(benzylthio)pyrrolo[1,2-a]benzimidazol-1-one has been established by X-ray crystallography.

In order to determine how solvents control the stereochemical course of the hot substitution reactions, the stereochemistry of the energetic ³⁸Cl for Cl was studied in diastereomeric 1,2-dichloro-1,2-difluoroethane and the geometric isomers of 1,2-dichlorohexa-fluorocyclobutane. In each system, the conformer population was determined by NMR and dipole moment techniques. A comparison was made between the changes of the stereochemical course of the substitution reaction and the concentration and nature of the solvent. The results presented in this investigation indicate that the stereochemical course of a hot atom substitution reaction is directly controlled by solvents participating in the de-excitation stabilization of excited compounds or in the relaxation process of intermediate radicals. This work also indicates that the nature of the solvent cage wall can control the progress of the hot reaction. Abstraction reactions of the Cl can occur in the cage with the compounds composing the cage wall. These reactions can effectively change the stereochemical course of the hot substitution reaction. It appears that the liquid phase hot atom substitution reactions observed in this investigation are best explained by the caged radical-radical combination model. Strong solute-solvent interactions reduce the time for relaxation of the radicals in the solvent cage thus preventing the radicals from obtaining planarity and consequently retention products. On the other hand, weak solute-solvent interactions increase the time for relaxation of the intermediate which leads to a racemization of reaction products. / Ph. D.

In soils spiked with gamma-HCH & DDT, and transplanted with wheat, the differences of gamma-HCH between the rhizosphere and non-rhizosphere soils increased with time, reached the peak on 30th sampling day, and then decreased with time. In the rhizosphere and non-rhizosphere soils, pp'-DDE/SigmaDDTs, op'-DDD/SigmaDDTs and pp'-DDD/SigmaDDTs increased with time; whilst op'-DDT/SigmaDDT and pp'-DDT/SigmaDDT decreased with time. The wheat, corn and soybean rhizosphere soils differed greatly in soil properties, but it was hard to conclude the effect of crop roots on the variation in concentration of gamma-HCH, p,p'-DDE, p,p'-DDD and p,p'-DDT in the rhizosphere soils except for root accumulation and translocation. / In the control, wheat and corn rhizosphere soils, the n-hexane extracted fraction of gamma-HCH, DDE, DDD and DDT decreased with time whereas the hexane/acetone extracted fraction increased with time after the 20th sampling day. The n-hexane extracted forms were higher in the rhizosphere soils than those in the non-rhizosphere soils, while the hexane/acetone extracted forms were lower in the rhizosphere soils than in the non-rhizosphere soils. / In the wheat, corn rhizosphere soils and the control, the concentration of NO3-N showed a significant negative correlation with n-hexane extracted DDE, DDD and DDT residues and a significant positive correlation with hexane/acetone extracted residues. The concentration of ammonium nitrogen (NH4-N) showed a significant negative correlation with hexane extracted gamma-HCH, DDE, DDD and DDT residues in the control, corn and wheat rhizosphere soils: but only had significant positive correlation with the n-hexane/acetone extracted fraction in the corn rhizosphere soil. The positive correlations between the n-hexane extracted residues of the target pesticides and soil OC were seldom significant in the control, sometimes significant in the wheat rhizosphere soils, and always strong and significant in the corn rhizosphere soils. The correlation of the n-hexane/acetone extracted residues with soil OC was positive and sometimes significant in the wheat rhizosphere soils, and significant and negative in the corn rhizosphere soils. The results indicated that the concentrations of different OCPs extracted from were strongly influenced by nutritional conditions and soil organic carbon. / Organic carbon (OC), dissolved organic carbon (DOC) and cultivation period were tested to explore their potential effects on target OCPs in the rhizosphere soils. The concentration of the target OCPs in the wheat rhizosphere soils increased proportionally to soil OC, whilst the uptake of OCPs by wheat roots and further translocation to the aboveground part were inversely proportional to soil OC. DOC only showed a negative correlation with concentration of p,p'-DDE and p,p'-DDT in the corn rhizosphere soils. After a longer root-soil interaction, roots had a more significant effect on the concentration of OCPs in the rhizosphere soils closer to the root surface. / The variation of different forms of OCPs in rhizosphere soils and their relationships with nitrogen nutrients and organic carbon were studied. / Variations in concentrations of organochlorine pesticide (OCP) residues in the rhizosphere soils were evaluated using rhizoboxes. A sequential extraction method was developed to study the fractionation and extractability of OCPs in rhizosphere soils. The key findings are as follows: / Zhu Xuemei. / "September 2006." / Adviser: Kin Che Lam. / Source: Dissertation Abstracts International, Volume: 68-03, Section: B, page: 1532. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (p. 265-288). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

Thesis (M. Sc)--York University, 2000. Graduate Programme in Physics and Astronomy. / Typescript. Includes bibliographical references (leaves 128-135). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://wwwlib.umi.com/cr/yorku/fullcit?pMQ59206.

Thesis (doctoral)--Lund University, 1997. / Added t.p. with thesis statement inserted.

Thesis (doctoral)--Lund University, 1997. / Added t.p. with thesis statement inserted.

Thesis (Ph.D.) -- McMaster University, 2001. / Includes bibliographical references (leaves 237-281). Also available via World Wide Web.

Thesis (Ph. D.)--Earth and Atmospheric Sciences, Georgia Institute of Technology, 2007. / Robert Dickinson, Committee Member ; Athanasios Nenes, Committee Member ; David Tan, Committee Member ; Armistead Russell, Committee Member ; Yuhang Wang, Committee Chair.