Thin film composite membranes were prepared by coating the surface of polyethersulfone ultrafilnation membranes with dilute solutions of sulfonated poly(2,6-dimethyl-1,4-phenylene oxide) polymer. Poly(2,6-dimethyl-1,4-phenylene oxide) was first sulfonated to different degrees, thus obtaining polymers of different ion exchange capacities, from which the coating solutions in methanol or methanol/chloroform mixtures were prepared. The reverse osmosis performance of the thin film composite membranes was studied using electrolyte solutes of different valences and ionic radii. The effect of the solvent used for the preparation of the polymer solution for surface coating was also investigated through testing the performance of the composite membranes in separating different electrolyte solutions as well as by micrographic techniques using a Scanning Electron Microscope and an Atomic Force Microscope. It was found that the preparation of thin film composite membranes with high selectivity and high flux was possible by adjusting properly the ion exchange capacity and the solvent used in making the coating solution. It was also found that the membrane performance was governed primarily by the ion exchange reaction between the solute cation and the proton in-SO$\sb3\sp{-}$H$\sp{+},$ as well as by the Donnan equilibrium. An attempt was also made to investigate the effect of changing the microporous substrate of the thin film composite membrane on the membrane permeation rate and selectivity. The porosity and the structure of the substrate play a significant role in determining the performance of the composit membrane.

A regenerable polystyrylboronic acid resin has been prepared for the selective functionalization of polyols. The resin reacts with a diol group of a polyol to form a resin-bound cyclic boronate. Both the coupling and cleavage steps are performed under very mild conditions (removal or addition of water) and the resin is regenerated directly by the cleavage step. Monoacyl derivatives of some acyclic polyols and some partially acylated carbohydrate derivatives have been prepared efficiently on the resin without the need for any purification of intermediates. In addition, the polystyrylboronic acid resin which exhibits a high selectivity for cis diol systems, can be used in the separation of cis and trans diol mixtures such as the cyclohexanediols by affinity chromatography.

Heat of polymerization. With the use of a Tian-Calvet microcalorimeter, the heats of polymerization of a number of monomers have been measured in aqueous emulsion systems; the emulsifying agent was cetyltrimethylammonium bromide, and initiation was by Fenton's reagent (Fe++ + H 2O2). The monomers employed were acrylic acid, methyl, ethyl and butyl acrylates, hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, methacrylic acid, and methyl, ethyl, butyl and hexyl methacrylates. The heats of polymerization lie in the range from 13 to 19 kcal per mole, the experimental standard deviation being 40 to 110 cal per mole. A steady increase was observed for acrylic acids and its CH3, C2H5 and C 4H9 esters, and for methacrylic acid and its CH3, C2H5, C4H9 C6H 13 esters. This change is attributed to a steady increase in the proportion of head to head, tail to tail polymers, leading to a decrease in steric hindrance in the polymer. Abnormally low heats observed with hydroxyethyl methacrylate and 2-hydroxypropyl methacrylate are attributed to the solvation of the monomer, less solvation being possible in the polymer as a result of shielding. Kinetics of polymerization. The microcalorimeter has been used to obtain rates of polymerization of a number of monomers in emulsion systems. The rates with the acrylates are consistently higher than those with the methacrylates, and this is attributed to there being less steric hindrance in the acrylate polymerization. Low rates found with the monomers containing a hydroxyl groups are explained as due to solvation in the initial monomer state. In both the acrylates and methacrylates the rates go through a maximum as one goes up the series methyl: ethyl: butyl: hexyl. This is discussed in terms of inductive and steric effects. Heats of vaporization. Heats of vaporization of fourteen alcohols, having from one to five carbon atoms, have been determined in a Calvet microcalorimeter, using a special technique. The method consisted of allowing the alcohol to vaporize into a vacuum, the heat required for the vaporization being provided by passing a current through a resistance wire which was immersed in oil in a U-tube surrounded by the alcohol. The additivity scheme previously devised by Laidler for heats of formation and related properties was applied to the results, and the agreement with experiment was within a few tenth of a percent. Additivity. An empirical bond energy scheme has been derived and applied to several physico-chemical properties of several families of compounds. The scheme proposed is a modification of Tatevskii's scheme. It defines three types of C-H bonds and several types of C-C bonds depending on their multiplicity and their environment. Other functional groups (e.g. -CHO, -COH) have been considered as a group and have been treated as such. They are assigned group symbols and their contribution to the physico-chemical property is a group contribution. The scheme has been applied to alkanes, alkenes, dienes and cylic hydrocarbons for the following properties; molar volume, molar refraction, entropy of formation and heat of atomization, all at 25°C. Molar sound velocities and diamagnetic susceptibilities are two other properties treated for several families of compounds.

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This thesis describes a variety of synthetic attempts to prepare dendrimer-metal complexes anchored to silica. The new complexes were obtained by immobilization of a tridentate diphosphinoaryl ligand (PCP-type) palladium(II) complex onto silica and silica supported dendrimers which combine the advantages of heterogeneous and homogeneous catalysts. They are thermally stable and they are also stable towards oxygen and moisture. These complexes show high catalytic activity for the Heck reaction of aryl iodides with styrene and n-butyl acrylate, resulting in high yields of stilbene and cinnamate ester. They are also active in the reactions of a variety of aryl bromides with n-butyl and methyl acrylate, providing para-substituted cinnamate esters in good yields. These complexes are also effective catalysts for the cyclocarbonylation reaction of 2-allylphenol yielding five- or seven-membered ring lactones in good selectivity and in high yields. In addition, these complexes can be recycled by simple filtration in air and reused with little to moderate loss of activity. In both kinds of reactions, the dendritic systems show higher activity compared to the non-dendritic systems.

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