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<p> The thermolysis of 2-diphenylmethylenehydrazono-5,5-dimethyl-Δ^3-1,3,4-oxadiazoline in vacuum and in chlorobenzene was studied. In both cases a stable 1-(diphenylmethylene)-4, 4-dimethyl-3-oxo-1,2-diazetidinium inner salt was obtained as the major product. The corresponding imino-oxirane, an isomer of the diazetidinium inner salt, is believed to be a precursor of the above product. Thermolysis of the same oxadiazoline in methanol gave benzophenone methyl carbazate and methyl isopropyl ether, probably involving the initial formation of an isocyanate as an intermediate.</p> / Thesis / Master of Science (MSc)

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My current thesis is regarding the application of Gel Permeation Chromatography (GPC) equipment and principles to the study of polyelectrolyte configuration in solution. The main focus of this study is the effect of salt on the hydrodynamic volume/solution properties of polyelectrolytes and the ability of GPC to effectively determine the degree of variation. This involves the comparison of different salt types and concentrations in aqueous solution. The specific polyelectrolyte examined is poly (2-methacryloyloxyethyl phosphorylcholine) (PMPC), a zwitterionic polymer (i.e. one having both positive and negative charges on the monomer). PMPC is a fairly new and promising polyelectrolyte for use in protein drug delivery and biomaterial surface applications. Understanding the effects of salt on this polyelectrolyte will aid in the development of technologies involving this polymer as well as other zwitterionic polymers. Different salts were utilized to formulate an effect of salt ions so that a systematic analysis could be performed. Using a control as reference it was determined that the salt does have an effect on the solution properties of the polyelectrolytes, as expected. The specific properties examined were characterized into two categories; solution properties and ion properties. Solution properties involved the investigation of salt concentration, solution ionic strength and solution pH effects. For ion properties, salts were selected on the basis of ion charge, charge type and ion size, so that the effects of both the cation and anion components could be analyzed. Two parameters, namely, ion size/type and ion valency were examined for both the cation and the anion. In addition the configuration of the anion was also investigated. vSpecific conclusions found in this study were as follows: 1) The salt concentration has an effect up to a certain "saturation" point. 2) The ionic strength has no visible effect (any effect is related to the concentration component). 3) There is no observable solution pH effect. 4) There is no observable cation effect. This includes no cation type/size or cation valency effect. 5) There is a significant anion effect. 6) A smaller anion has a greater effect than a larger anion. 7) A divalent anion has a greater effect than a monovalent anion. 8) A monatomic anion has a greater effect than a polyatomic anion. It was found that the effect of ion properties is related to mechanisms associated with the geometry of the polyelectrolyte. The negative charge group of the polyelectrolyte which is situated closer to the backbone (inside) is less important to the change in hydrodynamic volume resulting from ionic interactions with the salts since it is shielded by the positive charge group situated at the end of the side chain (outside). The observed phenomena were also explained by other chemical and physical properties such as charge density and ionic potential. In addition to the original plan of study, other phenomena were observed and later explained, such as the presence of four distinct regions associated with salt concentration and the variation m the degree of hydrodynamic volume change with different molecular weight samples. The application of aqueous GPC equipment (including a differential refractive index detector (DRI)) and principles to the study of polyelectrolyte solution effects minimizes the detection equipment required and, provides sufficient resolution and accuracy for examination of solution properties while remaining time and cost effective. The project discoveries have shown that size exclusion chromatography provides an excellent means of obtaining a complete and accurate set of correlations between polyelectrolyte charge and salt effects. / Thesis / Master of Applied Science (MASc)

One of the most common environmental exposures that nylon undergoes, when used for automotive applications, is that of salt splash, which commonly occurs during winter driving. This study looks at the effect of various salts (NaCl, KCl, CaCl2) on the thermal and mechanical properties of nylon when exposed to one and four molar aqueous salt solutions. It was found that the diffusion of salt solutions into nylon 6,6 occurred in a pseudo-Fickian manner. Also, it was found that the presence of salt had an effect on the rate of decrease of yield stress with increasing exposure time. The presence of residual salt was found to accelerated deterioration of nylon 6,6, possibly via hydrolysis. In addition, it was found that residual salt was left after water was removed from the system and that this salt was removable. / Master of Science

Soil salinity affects over 20% of the worlds irrigated land. Potato (Solanum tuberosum L.), the most important vegetable crop worldwide, is relatively salt sensitive. However, relatively little work has been done on salt tolerance of the potato plant. This thesis investigated the methodology of treatment application and scion/rootstock effects on subsequent salt stress responses of four contrasting potato genotypes: Norland, 9506, 9120-05 [ABA-deficient mutant], and 9120-18 [ABA-normal sibling] grown hydroponically in sand. The effect of incremental salt stress were studied, using NaCl, CaCl2 and combined NaCl + CaCl2 pre- treatments as well as varying methods of ABA application with a specific focus on the role of rootstock and scion. Physiological responses of various potato genotypes to salt stress differed depending on how the salt stress was applied. An incremental salt stress regime was able to more effectively differentiate genotypes based on salt stress resistance and greater salt tolerance compared to a sudden salt shock. Generally, the ability to produce ABA was positively related to the degree of salt stress resistance, with higher ABA levels induced under incremental salt stress treatments compared to salt shock. The method of ABA application also had a marked effect on potato responses to salt stress. Slowly increasing concentrations of exogenous ABA maintained growth rates, enhanced root water content and induced more lateral shoot growth compared to a single ABA dose. The degree of salt tolerance induced by the grafted rootstock was primarily modulated by salt acclimation and was manifested in the scion as increased water content, stem diameter, dry matter accumulation, stomatal conductivity, and osmotic potential and was associated with reduced leaf necrosis. Using the salt-resistant 9506 line as a scion also significantly increased root fresh and dry weight and stem diameter as well as root water content of salt-sensitive ABA-deficient mutant rootstocks. Exogenous ABA appeared to enhance plant water status via the roots under salt stress beyond that of grafting alone. This was verified by more positive stomatal conductivity and greater upward water flow in ABA treated grafted and non-grafted plants as compared to the absence of upward water flow in non-treated grafted plants as measured via micro NMR imaging. NaCl pre-treatment produced greater salt stress resistance compared to pre-treatment with CaCl2 and was associated with a specific Na+ ion effect rather than a non-specific EC-dependent response. However, the presence of both ABA and CaCl2 appears to be necessary in order to enhance Na+ exclusion from the shoot and increases the K+/Na+ ratio.

Soil salinity affects over 20% of the worlds irrigated land. Potato (Solanum tuberosum L.), the most important vegetable crop worldwide, is relatively salt sensitive. However, relatively little work has been done on salt tolerance of the potato plant. This thesis investigated the methodology of treatment application and scion/rootstock effects on subsequent salt stress responses of four contrasting potato genotypes: Norland, 9506, 9120-05 [ABA-deficient mutant], and 9120-18 [ABA-normal sibling] grown hydroponically in sand. The effect of incremental salt stress were studied, using NaCl, CaCl2 and combined NaCl + CaCl2 pre- treatments as well as varying methods of ABA application with a specific focus on the role of rootstock and scion. Physiological responses of various potato genotypes to salt stress differed depending on how the salt stress was applied. An incremental salt stress regime was able to more effectively differentiate genotypes based on salt stress resistance and greater salt tolerance compared to a sudden salt shock. Generally, the ability to produce ABA was positively related to the degree of salt stress resistance, with higher ABA levels induced under incremental salt stress treatments compared to salt shock. The method of ABA application also had a marked effect on potato responses to salt stress. Slowly increasing concentrations of exogenous ABA maintained growth rates, enhanced root water content and induced more lateral shoot growth compared to a single ABA dose. The degree of salt tolerance induced by the grafted rootstock was primarily modulated by salt acclimation and was manifested in the scion as increased water content, stem diameter, dry matter accumulation, stomatal conductivity, and osmotic potential and was associated with reduced leaf necrosis. Using the salt-resistant 9506 line as a scion also significantly increased root fresh and dry weight and stem diameter as well as root water content of salt-sensitive ABA-deficient mutant rootstocks. Exogenous ABA appeared to enhance plant water status via the roots under salt stress beyond that of grafting alone. This was verified by more positive stomatal conductivity and greater upward water flow in ABA treated grafted and non-grafted plants as compared to the absence of upward water flow in non-treated grafted plants as measured via micro NMR imaging. NaCl pre-treatment produced greater salt stress resistance compared to pre-treatment with CaCl2 and was associated with a specific Na+ ion effect rather than a non-specific EC-dependent response. However, the presence of both ABA and CaCl2 appears to be necessary in order to enhance Na+ exclusion from the shoot and increases the K+/Na+ ratio.