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Dimethyl ether (DME), as a solution to environmental pollution and diminishing energy supplies, can be synthesized more efficiently, compared to conventional methods, using a catalytic distillation column for methanol dehydration to DME over an active and selective catalyst. In current work, using an autoclave batch reactor, a variety of commercial catalysts are investigated to find a proper catalyst for this reaction at 110-135 C and 900 kPa. Among the -Alumina, Zeolites (HY, HZSM-5 and HM) and ion exchange resins (Amberlyst 15, Amberlyst 35, Amberlyst 36 and Amberlyst 70), Amberlyst 35 and 36 demonstrate good activity for the studied reaction at the desired temperature and pressure. Then, the kinetics of the reaction over Amberlyst 35 is determined. The experimental data are described well by Langmuir-Hinshelwood kinetic expression, for which the surface reaction is the rate determining step. The calculated apparent activation energy for this study is 98 kJ/mol. / Chemical Engineering

The chemical industry of today is under increased pressure to develop novel green materials, bio-fuels as well as sustainable chemicals for the chemical industry. Indeed, the endeavour is to move towards more eco-friendly cost efficient production processes and technologies and chemical transformation of renewables has a central role considering the future sustainable supply of chemicals and energy needed for societies. In the Nordic countries, the importance of pulping and paper industry has been particularly pronounced and the declining European demand on these products as a result of our digitalizing world has forced the industry to look at alternative sources of revenue and profitability. In this thesis, the production of levulinic and formic acid from biomass and macromolecules has been studied. Further, the optimum reaction conditions as well as the influence of the catalyst and biomass type were also discussed. Nordic sulphite and sulphate (Kraft) cellulose originating from two Nordic pulp mills were used as raw materials in the catalytic synthesis of green platform chemicals, levulinic and formic acids, respectively. The catalyst of choice used in this study was a macro-porous, cationic ion-exchange resin, Amberlyst 70, for which the optimal reaction conditions leading to best yields were determined. Cellulose from Nordic pulp mills were used as raw materials in the catalytic one-pot synthesis of ‘green’ levulinic and formic acid. The kinetic experiments were performed in a temperature range of 150–200 °C and an initial substrate concentration regime ranging from 0.7 to 6.0 wt %. It was concluded that the most important parameters in the one-pot hydrolysis of biomass were the reaction temperature, initial reactant concentration, acid type as well as the raw material applied. The reaction route includes dehydration of glucose to hydroxymethylfurfural as well as its further rehydration to formic and levulinic acids. The theoretical maximum yield can hardly be obtained due to formation of humins. For this system, maximum yields of 59 mol % and 68 mol % were obtained for formic and levulinic acid, respectively. The maximum yields were separately obtained in a straight-forward conversion system only containing cellulose, water and the heterogeneous catalyst. These yields were achieved at a reaction temperature of 180 °C and an initial cellulose intake of 0.7 wt % and belong to the upper range for solid catalysts so far presented in the literature. The reaction network of the various chemical species involved was investigated and a simple mechanistic approach involving first order reaction kinetics was developed. The concept introduces a one-pot procedure providing a feasible route to green platform chemicals obtained via conversion of coniferous soft wood pulp to levulinic and formic acids, respectively. The model was able to describe the behaviour of the system in a satisfactory manner (degree of explanation 97.8 %). Since the solid catalyst proved to exhibit good mechanical strength under the experimental conditions applied here and a one-pot procedure providing a route to green platform chemicals was developed. A simplified reaction network of the various chemical species involved was investigated and a mechanistic approach involving first order reaction kinetics was developed.

Thesis (MTech (Chemistry))--Cape Peninsula University of Technology, 2016. / The main purpose of this study is to understand the application of ion exchange chromatography on separation of charged ions of elements. Ion exchange chromatography is an analytical method, which is used for the separation of elements, quantitation and qualitation. The use of Amberlyst 15 resin as a source of separation for metal ions has been investigated and studies in various academic disciplines such as chemistry and material science. In this research study, Amberlyst 15 resin was investigated in order to understand the separation of positively charged divalent elements ions (Zn2+, Cu2+, Co2+ and Ni2+). The use of nitric acid and methanol mixture enhanced separation of these metal ions by ensuring that nitric acid is constant and varying methanol concentration. In this study, it was found that the resin has a high affinity for the metal ions at high methanol concentration, hence the distribution coefficient values increase but decreases at low methanol concentrations. The complexities of molecular structure of the salts of the elements provide the more understanding of the metal ion interaction with the resin particle. Furthermore, the role and strength of nitric acid to break the structural bonds and release the metal ions to get sorbed on the resin remains the most essential factor of understanding distribution coefficient values. Method validation parameters such as linearity, precision and accuracy of the method were determined. The method precision and accuracy were determined from the QC samples which is expressed as relative error (%RE) with the total coefficient of variation (%CV’s) were < 20%.

The price of crude glycerol has significantly decreased worldwide because of its oversupply. Many chemical and biological processes have been proposed to transform glycerol into numerous value-added products, such as glycolic acid, 1,3-propanediol (1,3-PDO), 1,2-propanediol (1,2-PDO), glyceric acid, and lactic acid. However, these processes suffer from several drawbacks, including high production cost. Therefore, in this study, a simple and robust electrochemical synthesiswas developed to convert glycerol into various value-added compounds. This study reports for the first time the use of Amberlyst-15 as a reaction mediumand redox catalyst for electrochemical conversion of glycerol. In the first part, the electrochemical performance of Amberlyst-15 over platinum (Pt)electrode was compared with that of conventional acidic (H2SO4) and alkaline (NaOH) media. Other parameters such as reaction temperature [room temperature (27°C) to 80 °C] and applied current (1.0 A to 3.0 A) were also examined. Under the optimized experimental condition, this novel electrocatalytic method successfully converted glycerol into glycolic acid after 8 h of electrolysis, with a yield of 45% and selectivity of 65%, as well as to glyceric acid after 3 h of electrolysis, with a yield of 27% and selectivity of 38%. In the second part of this study, two types of cathode electrodes, namely, activated carbon composite(ACC) and carbon black diamond (CBD) electrodes, were used in electrochemical conversion of glycerol. To the best of our knowledge, electrochemical studies of glycerol conversion using these electrodes have not been reported yet. Glycerol was also successfully reduced to lactic acid, 1,2-PDO, and 1,3-PDO, in addition to oxidation compounds (e.g. glycolic acid). Three operating parameters, namely, catalyst amount (6.4% to 12.8% w/v), reaction temperature [room temperature (27 °C) to 80 °C], and applied current (1.0 A to 3.0 A), were tested. In the presence of 9.6% w/v Amberlyst-15 at 2.0 A and 80 °C, the selectivity of glycolic acid can reach 72% and 68% (with yield of 66% and 58%) for ACC and CBD electrodes, respectively. Lactic acid was obtained as the second largest compound, withselectivity of 16% and yield of 15% for the ACC electrode and 27% selectivity and 21% yield for the CBD electrode. Finally, electro-oxidation and electroreduction of glycerol were performed in a two-compartment cell separated by a cation exchange membrane (Nafion 117). This study only focused on the electroreduction region. Three cathode electrodes (Pt, ACC, and CBD) were evaluated under the following conditions: 2.0 A, 80 °C, and 9.6% w/v Amberlyst-15. ACC demonstrated excellent performance in the electroreduction study and successfully reduced glycerol to 1,2-PDO, with a high selectivity of 85%. The selectivity of 1,2-PDO on Pt and CBD was 61% and 68%, respectively. Acetol and diethylene glycol were also obtained. The reaction mechanisms underlying the formation of these products are then proposed.

Au cours des dernières années, la production excédentaire et sans cesse croissante de bioglycérol a provoqué une chute spectaculaire de son prix. Au cours des dernières années, un grand nombre de processus chimiques et biologiques ont été élaborés pour transformer le bioglycérol en divers produits à haute valeur ajoutée, tels que la dihydroxyacétone, l'acide glycolique, le 1,3-propanediol (1,3-PDO), 1,2-propanediol (1,2-PDO), l'acide glycérique, l'acide lactique, le carbonate de glycérol etc. Malheureusement, ces procédés souffrent de nombreux inconvénients comme par exemple, un coût élevé de production. Par conséquent, dans cette étude, une synthèse simple et robuste, basée sur un processus électrochimique a été introduite afin de convertir le bioglycérol en une grande variété de composés à haute valeur ajoutée. Cette étude rapporte pour la première fois l'utilisation de la résine Amberlyst-15 comme milieu réactionnel et comme catalyseur d'oxydo-réduction pour la conversion électrochimique du glycérol. La performance électrochimique du système composé par la résine Amberlyst-15 et l’électrode au platine (Pt), a été comparée à celle utilisant un milieu électrolytique conventionnel acide (H2SO4) ou alcalin (NaOH). D'autres paramètres tels que la température de réaction (température ambiante à 80 °C) et l’intensité du courant appliqué (1,0 A à 3,0 A) ont également été examinés. Dans les conditions expérimentales optimales, ce nouveau procédé électrocatalytique permet de convertir le glycérol, soit en acide glycolique, avec un rendement de 45% et une sélectivité élevée de 65%, soit en acide glycérique, avec un rendement de 27% et une sélectivité de 38%. D’autre part, deux autres électrodes ont été préparées et testées dans la réaction de transformation du glycérol : une électrode au charbon actif (ACC) et une électrode composite au noir de carbone et diamant CBD). A notre connaissance, il n’existe pas dans la littérature d’étude de transformation électrochimique du glycérol utilisant ce type d’électrodes. Dans ce travail, nous avons montré que le glycérol peut être oxydé en divers composés d’oxydation mais peut également être réduit avec succès en acide lactique,1,2-PDO et 1,3-PDO. Trois paramètres de fonctionnement, tels que la quantité de catalyseur (6.4 -12.8% w/v), la température de réaction [température ambiante (27°C) à 80 °C] et l’intensité du courant appliqué (1,0 A à 3,0 A), ont été testés. L'étude a révélé que, pour une quantité de catalyseur 9.6% w/v Amberlyst-15, un courant de 2,0 A et une température de 80 °C, la sélectivité en acide glycolique peut atteindre jusqu'à 72% et 68% (avec un rendement de 66% et 58%) en utilisant respectivement l’électrode ACC et l’électrode CBD. L'acide lactique a aussi été obtenu avec une sélectivité de 16% et un rendement de 15% en utilisant l’électrode ACC et une sélectivité de 27% pour un rendement de 21% dans le cas de l'électrode CBD. Enfin, l'électrooxydation et l'électro-réduction du glycérol a été effectuée dans une cellule à deux compartiments séparés par une membrane échangeuse de cations (Nafion 117). L’étude s’est focalisée sur l’électro-réduction. Trois cathodes (Pt, ACC et CDB) ont été évaluées dans les conditions suivantes : 2.0 A, 80 °C et 9.6% w/v Amberlyst-15. Les trois électrodes ont permis de réduire le glycérol en 1,2-PDO. Nous avons obtenu une sélectivité de 61% avec l’électrode au Pt et une sélectivité de 68% avec L’électrode CBD. En fait, c’est l’électrode ACC qui a démontré les meilleures performances puisqu’elle a permis de réduire le glycérol en 1,2-PDO avec une sélectivité élevée de 85%. Enfin, la réaction conduit aussi à la formation d’acétol et de diéthylèneglycol. Les mécanismes de formation des différents produits obtenus à partir de chaque réaction sont proposés. / The price of crude glycerol has significantly decreased worldwide because of its oversupply. Many chemical and biological processes have been proposed to transform glycerol into numerous value-added products, such as glycolic acid, 1,3-propanediol (1,3-PDO), 1,2-propanediol (1,2-PDO), glyceric acid, and lactic acid. However, these processes suffer from several drawbacks, including high production cost. Therefore, in this study, a simple and robust electrochemical synthesiswas developed to convert glycerol into various value-added compounds. This study reports for the first time the use of Amberlyst-15 as a reaction mediumand redox catalyst for electrochemical conversion of glycerol. In the first part, the electrochemical performance of Amberlyst-15 over platinum (Pt)electrode was compared with that of conventional acidic (H2SO4) and alkaline (NaOH) media. Other parameters such as reaction temperature [room temperature (27°C) to 80 °C] and applied current (1.0 A to 3.0 A) were also examined. Under the optimized experimental condition, this novel electrocatalytic method successfully converted glycerol into glycolic acid after 8 h of electrolysis, with a yield of 45% and selectivity of 65%, as well as to glyceric acid after 3 h of electrolysis, with a yield of 27% and selectivity of 38%. In the second part of this study, two types of cathode electrodes, namely, activated carbon composite(ACC) and carbon black diamond (CBD) electrodes, were used in electrochemical conversion of glycerol. To the best of our knowledge, electrochemical studies of glycerol conversion using these electrodes have not been reported yet. Glycerol was also successfully reduced to lactic acid, 1,2-PDO, and 1,3-PDO, in addition to oxidation compounds (e.g. glycolic acid). Three operating parameters, namely, catalyst amount (6.4% to 12.8% w/v), reaction temperature [room temperature (27 °C) to 80 °C], and applied current (1.0 A to 3.0 A), were tested. In the presence of 9.6% w/v Amberlyst-15 at 2.0 A and 80 °C, the selectivity of glycolic acid can reach 72% and 68% (with yield of 66% and 58%) for ACC and CBD electrodes, respectively. Lactic acid was obtained as the second largest compound, withselectivity of 16% and yield of 15% for the ACC electrode and 27% selectivity and 21% yield for the CBD electrode. Finally, electro-oxidation and electroreduction of glycerol were performed in a two-compartment cell separated by a cation exchange membrane (Nafion 117). This study only focused on the electroreduction region. Three cathode electrodes (Pt, ACC, and CBD) were evaluated under the following conditions: 2.0 A, 80 °C, and 9.6% w/v Amberlyst-15. ACC demonstrated excellent performance in the electroreduction study and successfully reduced glycerol to 1,2-PDO, with a high selectivity of 85%. The selectivity of 1,2-PDO on Pt and CBD was 61% and 68%, respectively. Acetol and diethylene glycol were also obtained. The reaction mechanisms underlying the formation of these products are then proposed.

ABSTRACT KINETIC STUDIES FOR THE PRODUCTION OF TERTIARY ETHERS USED AS GASOLINE ADDITIVES Boz, Nezahat Ph. D., Department of Chemical Engineering Supervisor: Prof. Dr. Timur Dogu Co-supervisor: Prof. Dr. G&uuml / lSen Dogu June 2004, 174 pages In the present study, the kinetics studies for etherification reactions were investigated in detail. In the first phase of present study, different acidic resin catalysts were prepared by the heat treatment of Amberlyst-15 catalysts at 220&deg / C at different durations of time and also by the synthesis of sulfonated styrene divinylbenzene cross-linked resins at different conditions. A linear dependence of reaction rate on hydrogen ion-exchange capacity was in 2M2B+ethanol reaction. However, in the case of 2M1B+ethanol reaction hydrogen ion-exchange capacities over 2.8 meq.H+/g did not cause further increase in reaction rate, which was concluded to be majorly due to significance of diffusional resistances. DRIFTS experiments carried out with alcohols, isobutylene, isoamylenes and TAME (tert-amyl-methyl-ether) in a temperature range of 333-353 K supported a Langmuir-Hinshelwood type reaction mechanism involving adsorbed isoolefins molecules forming a bridged structure between &ndash / SO3H sites of the catalyst and adsorbed alcohol molecules. A rate expression derived basing on the mechanism proposed from the DRIFTS results gave good agreement with the published data. Reaction rate was found to give a sharp maximum at ethanol activity of around 0.1. The third phase of this work included evaluation of effective diffusivities and adsorption equilibrium constants of methanol, ethanol and 2M2B, in Amberlyst-15 from moment analysis of batch adsorber dynamic results. Models proposed for monodisperse and bidisperse pore structures were used for the evaluation of effective diffusivities. It was shown that surface diffusion contribution was quite significant. In the last phase of the work, a batch Reflux-Recycle-Reactor (RRR) was proposed, modeled and constructed to achieve high yields and selectivities in equilibrium limited reactions. The batch reflux recycle reactor was modeled by assuming plug flow in the reactor section, perfect mixing in the reboiler and vapor-liquid equilibria between the liquid in the reboiler and reactor inlet stream. In this system conversion values of isoamylenes reaching to 0.91 were achieved at 82&deg / C with almost 100% selectivity. Such conversion values were shown to be much higher than the corresponding equilibrium values that could be obtained in vapor phase fixed bed reactors. The activation energies evaluated in this system were found to be much less than the activation energies evaluated in the fixed bed reactor studies. This was concluded to be majorly due to the significance of transport resistant in the batch Reflux-Recycle-Reactor in which catalyst particles are partially wet. As a result of catalyst development, characterization, kinetic and reactor development studies carried out in this study, it was concluded that tert-amyl-ethyl-ether (TAEE) could be effectively produced and used as a gasoline blending oxygenate.

This master thesis deals with an optimization of processes of isolation of ferulic acid from wheat bran. Process of isolation based on alkaline hydrolysis from the substance and its adsorption was tested. In the theoretical part were described wheat bran, adsorption proces and used methods. For adsorption were tested five types of adsorbents. Especially these adsorbents: activation carbon (2,53 ± 1,16 mg.l-1), Amberlyst A-21 (105,73 ± 11,87 mg.l-1, Amberlit XAD-16 (241,55 ± 10,42 mg.l-1), Amberlit IRA-900Cl (5,90 ± 0,68 mg.l-1) and Amberlit IRA-96 (189,16 ± 6,49 mg.l-1). As the most efficient adsorbent was determine Amberlit XAD-16. The whole process has underwent detailed optimization in order to maximize the purity of the final product. The isolate was characterized by HPLC and FTIR techniques for ferulic acid and related phenolic acids. Based on FTIR analysis was discovered that the isolate was contamined by proteins. A purification procedure based on deproteination of the raw material before the hydrolysis itself was proposed. As the ultimate solution that eliminated the presence of proteins in the isolate was determine ultrafiltration with capture of molecules with Mw > 10 KDa. Ferulic acid yield from one kilo of wheat bran was 1,00 ± 0,22 g.