A series of ferrocenylimine [(£b5-C5H5)Fe(£b5-C5H4-C(Me)=N-R)]¡AR= nhexyl(1a)¡Acyclohexyl(1b)¡Aphenyl(1c)¡AN,N-dimethylethylamino(1d) ¡A4-methoxyphenyl(1e)¡A4-nitrophenyl(1f)¡Aand 2-methoxyethyl(1g)¡Ahave been synthesized by reaction of acetylferrocene and the corresponding amines through condensation reaction. Also 1,1¡¦-ferrocenyldiimines [Fe{(£b5-C5H4)-C(Me)=N-R}2]¡AR= nhexyl(2a)¡Acyclohexyl(2b)¡Aphenyl(2c)¡AN,N-dimethylethylamino(2d)¡A4-methoxyphenyl(2e)¡A4-nitrophenyl(2f)¡A3-nitrophenyl(2g)¡A2-methoxyethyl(2h) have been synthesized by reaction of 1,1¡¦-diacetylferoocene and the corresponding amines through condensation reaction. Solid state crystal X-ray structural analysis revealed the geometry of the ferrocene derivatives are various with the different substituents . In addition, these ferrocene derivatives might coordinate with CuBr to form a series of iminoferrcenyl copper(¢¹) complexes. Solid state crystal X-ray structural analysis revealed the iminoferrcenyl copper(¢¹) complexes 3a~3d showed monomeric or dimeric geometry and diiminoferrcenyl copper(¢¹) complexes 4a~4d exhibited polymeric or dimeric geometry. All synthesized ferrocenylimine and1,1¡¦-ferrocenyldiimines derivatives exhibited a reversible one ¡Velectron redox process in their cyclic voltammograms, and the values of their redox potentials relied on the R groups. The correlation between the redox potential and the Hammett substituent constant, £mp was quite well, with a correlation coefficient of 0.96 in CH2Cl2 and CH3CN. According to the cyclic voltammograms, iminoferrocenyl copper complexes showed that the substituents on the imino parts strongly affect the redox potentials of the iron centers in the ferrocenyl segments as well as the copper metal center. The Cu+/Cu2+ couple redox potentials are in the range of 0.269V and 0.719V dependent on solvent effect. The iminoferrocenyl copper complexes¡¦s UV-vis absorption seems to be red shift comparing with iminoferrocene. In the CH2Cl2, compound 3a¡B3b¡B4d shows emission at £fmax ~ 408 nm . In the CH3CN, compound 3a¡B3b¡B3c¡B3d¡B4a¡B4b and 4c show the blue shift emission band comparing with iminoferrocenyl copper complexes in CH2Cl2. In addition, complex 4d in CH2Cl2 and complex complex 3d in CH3CN showed higher quantum yield value. Moreover, compound 1a and 2a combined with CuBr exhibit good catalytic activity and controlling ability in the MMA ATRP process.

A new method for polybenzoxazine synthesis was developed and carried out throughout this work. Bisphenol-A, hexamethylenediamine, and paraformaldehyde were reacted through Mannich condensation reaction forming polybenzoxazine precursors. The reaction was followed by Gel Permeation Chromatography (GPC) as a molecular weight determination method in order to decide the end of reaction. The synthesized product, polybenzoxazine precursors, was polymerized thermally. Polybenzoxazine precursors were also characterized by using spectroscopic methods, 1H-NMR and FTIR, giving an approximation to structural determinations. Thermal characterization of precursors and polybenzoxazine showed that the materials had two exotherms at around 220&ordm / C and 260&ordm / C. The first exothermic peak was an indication of polymerization and preliminary crosslinking reactions while the second peak was due to the final polymerization of polybenzoxazine precursors. These precursors showed no significant structural change in isothermal period of 20 minutes at 200, 220, 225, 235&ordm / C. Mechanical tests were performed on the polybenzoxazine films. The films cured at 180&ordm / C possessed a tensile strength at break 21.04 (&plusmn / 3.56) MPa and an average elongation of 2.7 (&plusmn / 0.93) %. Young&rsquo / s modulus was calculated as 0.93 (&plusmn / 0.05) GPa for polybenzoxazine films.

Les lignines ne sont pas suffisamment considérées dans les procédés de bioraffinerie. Pourtant, elles sont une source abondante de synthons aromatiques, et éléments essentiels de la rentabilité de transformation des lignocelluloses. A ce jour, les perspectives de production de synthons à partir des lignines se heurtent aux réactions de condensations des lignines, limitant leurs conversions en produits de faibles masses. Cette étude nous a permis de cerner les conditions propices à l’hydrolyse et/ou aux condensations grâce à l’étude de différentes lignines modèles soumises aux conditions d’acidolyse. D’une part, les conditions propices à l’hydrolyse des liaisons -O-4 sont l’utilisation d’une catalyse homogène (HCl), pour des températures comprises entre 120 et 140°C et une acidité de l’ordre de 0.05 M. A l’inverse, l’emploi d’une catalyse hétérogène (Montmorillonite K10) est peu efficace car elle doit s’affranchir des phénomènes d’adsorption du substrat tout en lui permettant d’accéder à ses sites actifs. D’autre part, les réactions de condensation secondaires sont exacerbées par l’emploi de l’argile de Montmorillonite, mais aussi par l’augmentation de l’acidité et de la température, elles mêmes nécessaires pour une bonne hydrolyse. La substitution de l’alcool coniférylique par le coniféraldéhyde permet de minimiser ces condensations secondaires du fait de sa forte stabilité dans les conditions d’acidolyse. Toutefois, l’incorporation de ce type de précurseur dans les lignines provoque une diminution de la fréquence des liaisons -O-4. Cette réduction du potentiel d’hydrolyse des lignines est compensée par l’exacerbation des réactions de rétroaldolisation. Pour les condensations primaires, l’acidolyse des lignines pures -O-4 nous permet d’affirmer que celles-ci, constantes face à l’augmentation de la concentration en acide et en nucléophiles aromatiques, seraient plutôt de type intramoléculaire. / Lignins are not sufficiently considered in the biorefinery processes. However, they are a rich source of aromatic building blocks, and essential elements of lignocellulose processing viability. Although the production prospects of building blocks from lignins exist, their strong affinities for condensation reactions limit the conversion into low molecular weight products. This study allowed us to identify hydrolysis or condensation suitable conditions by studying different models lignins subjected to acidolysis conditions. On the one hand, suitable conditions for the -O-4 bonds hydrolysis are the use of homogeneous catalysis (HCl), for temperatures and HCl concentration ranged from 120 to 140 ° C and from 0.05 M to 0.1M. In contrast, the use of heterogeneous catalysis (Montmorillonite K10) is inefficient because it has to overcome the substrate adsorption and allow an access to its active sites. On the other hand, secondary condensation reactions are exacerbated by the use of Montmorillonite clay, but also by acidity and temperature increases, themselves necessary for an efficient hydrolysis.The substitution of coniferyl alcohol by coniferaldehyde minimizes these condensation reactions due to its high stability in acid conditions. However, the incorporation of this precursor in lignin leads to a decrease of -O-4 bond frequency. This reduction of lignin hydrolysis potential is compensated for the exacerbation of retroaldolisation reactions. About primary condensations, pure -O-4 lignins acidolysis allows us to claim that this kind of reactions, unchanged at the hand of acid or aromatic nuclei concentration increase, are intramolecular.

Atmospheric aldol self-reactions of octanal, heptanal and hexanal in a range of aqueous H2SO4 w/v% concentrations as a catalyst were studied in both bulk liquid-liquid experiments and gas-liquid experiments. Initially, a new practical methodology was developed and enhanced to monitor aldol reactions in aqueous acidic media. The evaluation of a quenching and extracting method were performed, confirming the suitability, reliability and reproducibility of the extraction method. In bulk studies, aldol products of the three aldehydes were separated and identified by preparative HPLC, GC-MS and NMR. The major aldol products observed at high acid concentrations were alpha,β-unsaturated aldehyde (dimer), trialkyl benzene (trimer) and tetraalkylcycloocta-tetraene (tetramer). The trimer of octanal was formed as trioxane in low sulfuric acid concentration and the possible mechanism accretion reaction pathways of high and low acid concentrations are proposed in this study. A systematic kinetic study of octanal, heptanal and hexanal in the bulk experiments at 65, 60 and 55 w/v% H2SO4 at 294 K were monitored using gas chromatographic equipped with a flame ionisation detector (GC-FID). The rate constants were generally estimated using second order kinetics and observed to increase as a function of sulfuric acid concentrations and also as the chain length of aliphatic aldehyde increased. The aldol self-reaction in the bulk experiment was too fast at room temperature to be easily measured using a quenching method therefore attempts were made to follow the reaction at low temperature (0 °C). The result at low temperature indicated that the rate constant of aldehyde was reduced but there was an issue of rapid rise in temperature as a result of mixing concentrated sulfuric acid with aqueous solution of the aldehyde. A gas bubbling system was developed which better simulates atmospheric reality, and which also resolves the issue of temperature rise on mixing. Two different methodologies were used: one in which the aldehyde was continually added, and one where a fixed amount was added from the gas phase and the reaction was then allowed to proceed, monitored at selected time intervals. The precision and accuracy of the fixed method was then further improved by the addition of an internal standard (IS). Using this, the concentrations of aliphatic aldehydes (C6-C8) were calibrated using an experimentally determined response factor and used to follow the loss of the reactant aldehydes. Similar methods were applied to the aldol dimers (C6-C8), which were purified and used to calibrate the chromatographic response. The rate constant for octanal, heptanal and hexanal at 76 wt% and 294 K were 0.0969 M-1 s-1, 0.1497 M-1 s-1 and 0.2622 M-1 s-1 respectively. There are some observations based upon the results presented in this thesis that may be of atmospheric significance: (i) phase separation between organic and aqueous layers in both the bulk experiment and in the bubbling system; (ii) the acid strength dependence and concentration-dependence of the various products; (iii) the faster rates than previously reported, and variation between bulk and bubbling; and (v) the time-dependent colour changes. Further work to explore these observations is proposed.

M.Sc. (Chemistry) / Please refer to full text to view abstract

Résumé anglais uniquement / Nowadays there is an urgent need to develop green chemical processes, where the use and generation of toxic substances can be avoided. Indeed, the lignocellulose feedstock destructuration will produce aqueous solutions of ketones or aldehydes and it would be an important breakthrough to develop solid base catalysts capable to promote the aldol condensation. In this thesis, the main results are shown as follows: Magnesium and rare earth mixed oxides (MgReOx), rare earth modified MgAl-HT catalyst were prepared and were evaluated in liquid phase acetone self-aldolization. Rare earth modified MgAl catalysts show enhanced catalystic activity than MgReOx catalysts. Rehydrated MgAl-HT modified with Y and La, also present a higher water tolerance for aldol reaction. The same catalysts were also applied to acetone gas phase self-condensation reaction. At low temperature, the mesityl oxide is the main product for all the catalysts. At high temperatures, deactivation rate is lowered over MgAlCe(Y)O catalysts, and the presence of trimers (selectivity of IP over 50%) is much more noticeable for the MgAlY(Ce)O catalysts. A good balance between basicity and acidity is proposed to increase the selectivity of IP. In the cross condensation of citral and acetone, the citral conversion and pseudoionone yield were significantly enhanced over Mg3AlaY1-aOx catalysts. A general mechanism of reaction was proposed that the Y modified MgAl mixed oxides undergoes the rehydration by the water formed during the reaction, and the rehydrated catalysts with active Brønsted basic sites are responsible for the significantly improvement of catalytic activity