One of today’s world's main challenges is access to a clean environment. The release of hazardous and toxic gases from burning fossil fuels is of critical concern due to these gases' destructive effects on the nearby atmosphere. Among these, acid rain is one of the most severe consequences of air pollution caused by sulfur dioxide (SO2) gas and still needs to be better addressed. One of the solutions is the adsorption-based technologies because of their ease of use, possible high adsorption capacity, minimum environmental impact, low cost, and efficient sorbate recovery possibilities. Gas separation via adsorption is not yet widely employed commercially since it needs regenerable, high-durable, high-performance, and cost-effective adsorbents. One of the common methods of absorbing acid gases is the use of amino absorbents that have disadvantages such as create many waste materials challenging to regenerate, wastewater, and waste gas. Therefore, incorporating amine groups on the surface of solids to overcome the problem of regeneration has attracted considerable attention in gas uptake. In this project, we proposed to functionalize nanocrystalline cellulose (NCC) using a solvent-free method to boost their SO2 interactions and thus their adsorption capability. Therefore, a commercial NCC material was modified using ethylenediamine (EDA) in green and straightforward amination approach in order to tune its surface basicity and obtain an efficient green-biobased adsorbent. Since the substitution process of amines with hydroxyl groups on the cellulose surface is carried out through dangerous halogen solvents, we used the solvent-free one-step method and investigated the synthetic parameters. Amination conditions of NCC adsorbents were optimized via the effects of the amination temperature, the amination time, and the amount of EDA on their physical properties and their performance for SO2 adsorption. The sorbents were characterized using attenuated total reflection-Fourier-transform infrared spectroscopy (ATR-FTIR), solid carbon nuclear magnetic resonance (13CNMR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and scanning electron microscopy- energy-dispersive X-ray spectroscopy (SEM-EDS) to see if EDA was incorporated into the NCC and investigate the changes in thermal stability of adsorbents by changing synthesis conditions. Sorbents were then tested for SO2 capture at the same conditions of room temperature (RT), atmospheric pressure, and a flow rate of 20 ml/min, which was selected based on previous studies to optimize flow rate in the same research group. The optimal conditions to create an effective sulfur dioxide adsorbent were found to be 70 oC for 8 hours of amination. At ideal conditions, the NCC modified had an SO2 adsorption capacity value of 0.030 mg/100 mg. The promising properties of EDA-NCC in terms of adsorption capacity (showing a significant increase in capacity when compared to the NCC at atmospheric pressure and ambient temperature) make them potential adsorbent candidates. In addition, the impacts of SO2 capture operating conditions on adsorption capacity were evaluated. By varying the adsorption temperature from room temperature to 60 °C and the feed flow rate from 10 to 30 ml min-1, fixed-bed breakthrough studies for SO2 adsorption onto NCC and modified-NCC adsorbent (prepared at 70oC, 3hr, and EDA/NCC=25) were carried out. Over the range of operating parameters studied, the greatest SO2 capacity and breakthrough time values were obtained with adsorbent at room temperature and 20 ml min-1 input flow rate. As expected, due to the exothermic nature of the adsorption process, the amount of SO2 adsorbed at equilibrium decreased with increasing temperature. It was also observed that as the flow rate increases, the breakthrough time decreases due to the higher flow rate of the feed gas was accompanied by the faster transport of the adsorbate molecules and leading to a shorter breakthrough time, as expected. Finally, another EDA functionalization method was tested, using a two-step method. First, cellulose was functionalized using citric acid (CA), and then the EDA was incorporated via carboxylic acid functional groups in the CA to obtain both amide and amine groups on the NCC’s surface. This approach aimed to compare EDA deposition on cellulose surface via a different method by adding one more functional group and evaluating their performance in SO2 gas adsorption. It was concluded that oxygenated functional groups and groups with low alkalinities, such as carboxylic acid and amide, can negatively affect gas adsorption. These results were concluded by comparing two adsorbents, one containing only amine groups and the other adsorbent containing amide and carboxylic acid groups in addition to the amine group, although the amine content of the two adsorbents was different. Future research will explore the mechanisms and capturing phenomena to improve capturing capacity and process applicability as well as the material optimal regeneration operating conditions.

Chemical processes and reactions are never perfect; there are always some problems in scope, scalability, applicability or safety. Sometimes, if these limitations pose a seemingly insurmountable barrier to the chemistry’s overall usefulness, decades can go by without a single new development even in fields that were initially very promising or popular in their infancy. By looking back on these forgotten topics through the lens of modern technology, new cutting-edge materials and methods can be applied to solve the problems that posed too great a challenge in previous decades. In this thesis, two such examples of reactions initially discovered and developed around the late 1960’s and remained largely untouched ever since will be explored. Chapter 1 will describe the use of ozone as an oxidant to transform amines into the corresponding alkyl nitro species. Ozone is a very powerful oxidant but tends to overreact with most organic substrates, which significantly reduces its potential as a commonplace synthetic tool. These limitations in applicability stem from an inherent lack of control over the reaction, which is the issue that we sought out to address. By applying modern principles of flow chemistry, the functional group tolerance of this oxidation reaction has been drastically increased from its initial state of simple small hydrocarbons. Chapter 2 will follow a similar narrative involving the use of ‘super-bases’ to activate benzylic C-H bonds and generate a variety of benzyllithium species. Organolithiums have also had historic issues with tolerance in transition metal-catalyzed cross coupling reactions. With a surge of new publications addressing this issue by using principles of flow chemistry, there remains a lack of easy methods to generate organolithium nucleophiles as coupling partners. Generation of benzyllithiums from toluene derivatives has historically been limited to require solvent quantities of substrate, along with unreasonably long reaction times at cryogenic temperatures. By utilizing modern tools and synthetic strategies, an easy and streamlined path from toluene derivatives to organolithiums for direct use in cross coupling has been developed.

No description available.

published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy

Thesis--Ph. D., University of Hong Kong, 1982. / Cover title.

Thesis--Ph. D., University of Hong Kong, 1982.

Thermodynamics is important for the design of amine scrubbing CO₂ capture processes. CO₂ solubility and amine volatility in aqueous amines were measured at high temperature and pressure. A rigorous thermodynamic model was developed for MEA-CO₂-H₂O in Aspen Plus®. CO₂ solubility at 80-190°C was obtained from total pressure measurements. Empirical models as a function of temperature and loading were developed for CO₂ solubility from 40 to 160°C in aqueous monoethanolamine (MEA), piperazine (PZ), 1-methylpiperazine (1MPZ), 2-methylpiperazine (2MPZ), PZ/2MPZ, diglycolamine® (DGA®), PZ/1MPZ/1,4-dimethylpiperazine (1,4-DMPZ), and PZ/methyldiethanolamine (MDEA). The high temperature CO₂ solubility data for MEA is comparable to literature and compatible with previous low temperature data. For MEA and PZ, amine concentration does not have obvious effects on the CO₂ solubility. The heat of CO₂ absorption derived from these models varies from 66 kJ/mol for 4 m (molal) PZ/4 m 2MPZ and to 72, 72, and 73 kJ/mol for MEA, 7 m MDEA/2 m PZ, and DGA. The heat of absorption estimated from the total pressure data does not vary significantly with temperature. At 0-0.5 loading ([alpha]), 313-413 K, 3.5-11 m MEA (mol fraction x is 0.059-0.165), the empirical model of MEA volatility is ln(PMEA/xMEA) = 30.0-8153/T-2594[alpha]²/T. In 7 m MEA with 0.2 and 0.5 loading, PMEA is 920 and 230 Pa at 120°C. At 0.3-0.5 loading, the enthalpy of MEA vaporization, -[Delta]Hvap,MEA, is about 70-73 kJ/mol MEA. At 0.25-0.4 loading, 313-423 K, 4.7-11.3 m PZ (x is 0.078-0.169), the empirical model of PZ volatility is ln(PPZ/xPZ) = -123+21.6lnT+20.2[alpha]-18174[alpha]²/T. In 8 m PZ with 0.3 and 0.4 loading, PPZ is 400 and 120 Pa at 120°C, and 2620 and 980 Pa at 150°C. At 0.25-0.4 loading, -[Delta]Hvap,PZ is about 85-100 kJ/mol PZ at 150°C and 66-80 kJ/mol PZ at 40°C. [Delta]Hvap,PZ has a larger dependence on CO₂ loading than [Delta]Hvap,MEA in rich solution because of the more complex speciation/reactions in PZ at rich loading. Specific heat capacity of 8 m PZ is 3.43-3.81 J/(g•K) at 70-150°C. Two new thermodynamic models of MEA-CO₂-H₂O were developed in Aspen Plus® starting with the Hilliard (2008) MEA model. One (Model B) includes a new species MEACOOH and it gets a better prediction than the other (Model A) for CO₂ solubility, MEA volatility, heat of absorption, and other thermodynamic results. The Model B prediction matches the experimental pKa of MEACOOH, and the measured concentration of MEACOO-/MEACOOH by NMR. In the prediction the concentration of MEACOOH is 0.1-3% in 7 m MEA at high temperature or high loading, where the heat of formation of MEACOOH has effects on PCO₂ and CO₂ heat of absorption. Model B solved the problems of Model A by adding MEACOOH and matched the experimental data of pKa and speciation, therefore MEACOOH may be considered an important species at high temperature or high loading. Although mostly developed from 7 m MEA data, Model B also gives a good profile for 11 m (40 wt%) MEA. / text

published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy

Hormis la préparation de l’acide salicylique et de l’urée, peu de tentatives ont été réalisées jusqu’à présent pour promouvoir la formation de liaisons C–C et C–N à partir du CO₂. Cette thèse présente de nouveaux procédés catalytiques permettant la formation de molécules organiques azotées grâce à la création de liaisons C–N et C–C par transformation catalytique du CO et du CO₂. Les cibles retenues sont les amides ainsi que les alkylamines qui sont essentiels en chimie organique fine et sont souvent d’origine pétrosourcés. Dans un premier temps, la synthèse d’amide par carbonylation formelle de la liaison C–N d'amine sera étudiée grâce à des catalyseurs à base de métaux carbonyles. Dans un second temps, des procédés d’homologation des amines seront décrits grâce à l’utilisation de catalyseurs métalliques. La première stratégie impliquera l’utilisation de catalyseur de cobalt, en présence de CO et de silanes et permettra l’homologation sélective des liaisons N-méthyle en N-éthyle sous de faible pression de CO (P = 8 bar) et jusqu’au N-pentyle sous de fortes pressions. Dans un second temps, l’utilisation d’un catalyseur de ruthénium en présence d’un gaz de synthèse (CO/H₂) nous permettra de démontrer la possibilité de l’homologation de la diphénylamine. Enfin, la compréhension de ce système nous permettra de transposer cette réaction à l’utilisation du CO₂ comme substitut du CO. / Apart from the preparation of salicylic acid and urea, few attempts have been made so far to promote the formation of C-C and C-N bonds from CO₂. This thesis describes new catalytic processes allowing the formation of nitrogen compounds through the creation of C-N and C-C bonds by catalytic transformations of CO and CO₂. The chosen targets are the amides and the alkylamines which are essential in fine organic chemistry and yet prepared from petrochemicals. In a first part, the amide synthesis by formal carbonylation of the C-N bond HAS been studied using catalysts based on first row transition metal carbonyl complexes. In a second part, methods enabling homologation of amines are described through the use of metal catalysts. The first strategy involved the use of cobalt catalysts in presence of CO and hydrosilanes which allow the selective homologation of N-methyl into N-ethyl derivatives under a low CO pressure (P= 8 bar). Also, the alkyl chain can be homologated under elevated CO pressures to reach N-pentyl derivatives. Finally, the use of a ruthenium catalyst in presence of a synthesis gas (CO / H₂) allowed us to demonstrate the possibility of the homologation of the diphenylamine. Understanding this system led to translate the amine homologation with syngas to the use of CO₂ as a substitute for CO.

Depuis le début du 21ème siècle, les liquides ioniques (LIs) représentent une importante source d'innovation dans la recherche académique et industrielle en chimie puisqu'ils peuvent être synthétisés, modulés puis utilisés dans de nombreuses applications. De par leurs avantages, les LIs font l'objet d'un véritable engouement dans le domaine des matériaux polymères. Ainsi, ce travail décrit la synthèse de sels organiques originaux pour le développement de polyélectrolytes inédits. Pour cela, nous avons développé de nouvelles voies d'accès à des imidazoliums fonctionnalisés par des fonctions époxydes par l’utilisation d'une méthodologie d'oxydation efficace, flexible et transposable sur une échelle de plusieurs grammes. L'analyse thermique de ces sels a dévoilé une excellente stabilité thermique jusqu'à 400 °C et une température de transition vitreuse basse généralement comprise entre -60 °C et -26 °C. A la suite de ces résultats, la stratégie a été élargie aux anions afin de proposer des fonctions époxydes associées à des sulfonimides inédits. Au cours de cette deuxième phase, l'insertion de fonctions époxydes sur l'anion sulfonimide a été réalisée avec succès permettant un accès à différents prépolymères comme un cation/anion triépoxyde. Dans une deuxième partie, nous avons réalisé une étude mécanistique en utilisant un sel monoépoxyde en présence de différentes amines pour identifier les principaux sites actifs lors de la polymérisation. Grace à ces informations, nous avons confirmé la stabilité de l’imidazolium et la très bonne réactivité de l’époxyde vis-à-vis de diverses amines conduisant à une meilleure compréhension de l'architecture globale du réseau. A partir de ces travaux, un réseau époxy inédit a été mis en œuvre en collaboration avec le laboratoire d'ingénierie des matériaux polymères (IMP) de l'INSA de Lyon. Pour cela, un sel diépoxyde a été sélectionné puis copolymérisé avec un durcisseur diamine (Jeffamine D230) afin de concevoir des réseaux époxy/amine flexibles présentant des propriétés très intéressantes par rapport aux réseaux époxy classiques. / Since the beginning of the 21th century, Ionic liquids (ILs) have been an important source of innovation in chemical academic and industrial research because they can be synthesized, modulated and used then in many applications. Because of their advantages, ILs are of great interest in the field of polymer materials. Thus, this work describes the synthesis of original organic salts to develop innovative polyelectrolytes. For this, we have developed new routes to access to imidazolium salts functionalized by reactive epoxide functions thanks to the development of an effective and flexible oxidative methodology, feasible on a large scale. The thermal analysis of this salts revealed a very good thermal stability up to 400°C and a low glass transition temperature between -60 °C and -26 °C generally. Following these results, the study was extended to anions to provide epoxides associated with novel sulfonimides. During this second phase, the insertion of epoxide functions on the sulfonimide anion was successfully carried out allowing access to different prepolymers such as a triepoxide cation/anion. In a second part, we carried out a mechanistic study using a monoepoxide salt in the presence of different amines to identify the main active sites during the polymerization. According to this information, we have confirmed the stability of the imidazolium and the very good reactivity of the epoxide with various amines leading to a better understanding of the overall architecture of the network. From this work, a novel epoxy network was prepared in collaboration with the polymer materials engineering laboratory (IMP) of INSA of Lyon. For this, a diepoxide salt was selected and copolymerized in the presence of a diamine hardener (Jeffamine D230) in order to design flexible epoxy/amine networks having very interesting properties in comparison with conventional epoxy networks.