Direct Activation of Light Alkanes to Value-Added Chemicals Using Supported Metal Oxide Catalysts

One of the most challenging aspects of modern-day catalysis is the conversion of methane. Direct conversion of methane via dehydroaromatization (MDHA) is a well-known process which can produce valuable hydrocarbons. Mo oxide supported on ZSM-5/MCM-22 has been studied extensively in recent years for MDHA. Mo carbides are responsible for activating methane by forming CHx species. These are dimerized into C2Hy and oligomerized on ZSM-5/MCM-22 Brønsted acid sites to form aromatics. Sulfated zirconia (SZ) supported Mo catalyst contains the acid sites necessary to produce benzene in MDHA. Here, sulfated hafnia (SH), a homologous oxide like SZ, has been proposed to provide the necessary acid sites as a novel support for Mo in MDHA. Conversion increased with higher temperature and lower space velocity and gradually deactivated with time. This can be attribute to catalytic surface coking, confirmed with subsequent TPO analysis. Benzene product selectivity increased with higher Mo loading, lower temperature and lower space velocity, while gradually decreasing with time. A direct comparison of conventional Mo/HZSM-5 synthesized here and under identical reaction conditions showed lower activity compared to the Mo-SH catalyst. To address catalytic coking and improve aromatics selectivity, several extensions of this project were carried out in this work. Additional of promoters like Pt, Cr, Pd to Mo-SZ catalysts showed improved benzene selectivity and overall activity of the modified catalysts. MDHA studies using group VIB metals (Cr, Mo, W) supported on SZ were also carried out to understand the effect of these active metals on SZ, which showed the superiority of Mo in terms of catalytic activity and benzene selectivity. Direct conversion of methane to C2 hydrocarbons using W/SZ is another demonstration of the versatility of this catalytic process. Additionally, Mo/SH was used to directly activate ethane and propane and selectively produce important industrial feedstocks like ethylene and propylene. Few alternate routes were suggested for low temperature conversion of methane using CO2 via bimetallic catalytic approaches to produce high value oxygenates. Based on thermodynamic analysis, prospective catalytic reaction mechanisms are discussed to overcome the thermodynamic energy constraints for CO2 and methane activation at low temperature with selective production of target oxygenates

Design of novel well-defined organorhenium heterogeneous catalyst for unsaturated fatty acid derivatives self-metathesis

La formation des liaisons C-C est parmi les cibles les plus élevés de la science et de la technologie de la catalyse. Dans ce cadre, la réaction de métathèse catalytique a gagné une importance considérable en raison de l'efficacité du processus de transformation. Par conséquent, un grand progrès a été réalisé dans ce domaine avec le développement de plusieurs catalyseurs homogènes et hétérogènes, ainsi que les différentes approches de métathèse. Cette formule a permis une conception plus facile et plus durable de diverses stratégies de synthèse dans différents domaines, y compris la synthèse organique, la science des polymères, etc. Cependant, le développement des catalyseurs de métathèse robustes pour les applications à grande échelle est encore une tâche difficile. Tenant compte de cela, les résultats de recherche présentés dans cette thèse de doctorat se concentrent sur la synthèse d'un nouveau catalyseur hétérogène de métathèse. Par conséquent, le méthyltrioxorhénium (MTO) a été supporté sur différents matériaux à base d'alumine. La performance des catalyseurs synthétisés a été étudié par l'auto-métathèse de l'oléate de méthyle, choisi comme substrat modèle; volumineux et fonctionnalisé, afin d'évaluer la tolérance des espèces actives aux groupements fonctionnels, ainsi que d'évaluer sa diffusion à l'intérieur des canaux mésoporeux. Tout d'abord, des supports très organisés à base alumine mésoporeux organisée modifiée avec le chlorure de zinc (ZnCl2-AMO) ont été préparés avec succès grâce à un procédé sol-gel puis une imprégnation post-synthèse. Le MTO supporté sur ces supports catalytiques est très actif pour l'auto-métathèse de l'oléate de méthyle, avec des vitesses de réaction plus élevées et une meilleure sélectivité par rapport aux catalyseurs à base d'alumine classiques. Cette amélioration est attribuée à des meilleurs phénomènes de transfert de masse à l'intérieur du réseau mésoporeux organisé. Ensuite, nous avons développé une voie de synthèse efficace en une seule étape pour la préparation des matériaux ZnCl2-AMO. Cette approche a permis l'accès à des supports ZnCl2-AMO très ordonnés avec de meilleurs rendements de synthèse ainsi que de meilleures propriétés physiques et de surface. En outre, ces fonctionnalités améliorées ont permis aux catalyseurs à base de MTO supportés sur ces matériaux préparés en une seule étape de manifester une meilleure performance catalytique par rapport à celle de ZnCl2-AMO préparé par le processus en plusieurs étapes. Toutefois, des études spectroscopiques ont révélé la formation d'espèces actives semblables sur la surface pour tous les supports catalytiques préparées. Ces caractérisations nous ont guidés pour étudier et proposer un mécanisme complet pour les voies de formation des produits de métathèse, ainsi que le cycle catalytique de métathèse, démontrant l'effet d'encombrement stérique sur l'interface de catalyseurs qui contrôle la sélectivité de la réaction. La synthèse des catalyseurs de métathèse MTO/ZnCl2-AMO nous a permis d'effectuer efficacement les transformations de métathèse utilisant des matières premières renouvelables (par exemple des acides gras estérifiés provenant des huiles végétales), offrant un accès à une variété de monomères fonctionnalisés, qui pourraient éventuellement être utilisés pour d'autres transformations telles que la synthèse des bio-polymères à valeur ajoutée à base (par exemple, les bioplastiques, biosurfactants).Sustainable C-C bond forming reactions have been among the highest target of catalysis science and technology. In this scope, metathesis reaction has been gaining enormous attention due to the efficiency of the transformation process. Therefore, a great progress has been made in this area by developing several homogeneous and heterogeneous catalysts as well as distinct metathesis reaction approaches. This allows an easier and more sustainable design for various synthesis strategies in different fields including organic synthesis, polymer science, etc. However, the development of robust metathesis catalysts for large scale applications is still a challenging task. Taking this into account, this research presented in this doctoral dissertation is focusing on the synthesis of new heterogeneous metathesis catalysts. Therefore, methyltrioxorhenium (MTO) was supported on various alumina-based materials. The synthesized catalysts' performance was studied though methyl oleate self-metathesis, chosen as a model bulky functionalized substrate, in order to evaluate the active species tolerance to functional groups as well as to evaluate its diffusion inside the mesoporous channels. First, highly organized ZnCl2-modified OMA supports were successfully prepared through a sol-gel method followed by a post-synthesis modification via wet-impregnation process. MTO supported on these catalytic supports were found o be highly active for methyl oleate self-metathesis, displaying higher reaction rate and products selectivity compared to the conventional wormhole-like alumina-based catalysts. This improvement is ascribed to enhanced mass transfer phenomena inside the organized mesoporous network. Afterwards, we have developed efficient one-pot synthesis route ZnCl2-modified OMA supports. Interestingly, this approaches allowed access to numerous highly ordered ZnCl2-modified OMA supports with better synthesis yields and improved textural and surface properties. Moreover, these enhanced features allowed the MTO-based catalyst supported on these one-step prepared materials to exhibit higher metathesis reaction performance compared to ZnCl2-modified OMA supports prepared via the two-steps processes. However, spectroscopic investigations revealed the formation of similar surface active species for all the prepared catalytic supports. These characterizations guided us to study and propose a comprehensive mechanism of metathesis products formation pathways as well as the metathesis catalytic cycle, demonstrating the steric hindrance effect on the catalysts interface that governed the reaction selectivity. The synthesis of the 3 wt.% MTO/ZnCl2-OMA catalysts allowed us to efficiently perform metathesis reaction using renewable feedstock (e.g. fatty acid esters derived from vegetable oils), offering access to a variety of functionalized monomers which could be used for further transformations such as the synthesis of value-added bio-based polymers (e.g. bioplastics, biosurfactants)

Heteropolycompounds as catalysts for biomass product transformations

[EN] In the present review we show a variety of biomass product transformations through catalysis by both bulk and supported heteropolycompounds. The biomass sources considered include carbohydrates, oils and fats, and terpenes as main starting material groups. The products obtained and their applications are presented.We thank CONICET (PIP 003), Agencia Nacional de Promocion Cientifica y Tecnologica (Argentina) (PICT 0406), and Universidad Nacional de La Plata for financial support. GPR and HJT are members of CONICET. MJC and SI thank to Spanish Government-MINECO through Consolider Ingenio 2010-Multicat project for financial support.Sanchez, LM.; Thomas, HJ.; Climent Olmedo, MJ.; Romanelli, GP.; Iborra Chornet, S. (2016). Heteropolycompounds as catalysts for biomass product transformations. Catalysis Reviews: Science and Engineering. 58(4):497-586. doi:10.1080/01614940.2016.1248721S49758658

CATALYSIS OF ETHANOL SYNTHESIS FROM SYNGAS

Catalytic synthesis of ethanol and other higher alcohols from CO hydrogenation has been a subject of significant research since the 1980s. The focus of this research is to establish a better fundamental insight into heterogeneous catalysis for CO hydrogenation reactions, in an attempt to design the best catalysts for ethanol synthesis. It has been reported widely that promoted Rh-based catalysts can exhibit high selectivity to C2+ oxygenates during CO hydrogenation. The doubly promoted Rh-La-V/SiO2 catalysts exhibited higher activity and selectivity for ethanol and other C2+ oxygenates than singly promoted catalysts. The better performance appears to be due to a synergistic promoting effect of the combined La and V additions through intimate contact with Rh. The kinetic study carried out in this study shows that, in general, increasing H2 pressure resulted in increased activities while increasing CO partial pressure had an opposite effect. Langmuir-Hinshelwood rate expressions for the formation of methane and of ethanol were derived and compared to the experimentally derived power law parameters. It was found that the addition of different promoters appeared to result in different rate limiting steps. Strong metal-oxide interactions (SMOI) of Rh and vanadium oxide (as a promoter) supported on SiO2 was studied. It was found by SSITKA (steady-state isotopic transient kinetic analysis) that the concentration of surface reaction intermediates decreased on Rh/V/SiO2 as the reduction temperature increased, but the activities of the reaction sites increased. The results suggest that Rh being covered by VOx species is probably the main reason for the decreased overall activity induced by high reduction temperature, but more active sites appear to be formed probably at the Rh-VOx interface. The mechanism of C1 and C2 hydrocarbon and oxygenate formation during CO hydrogenation on Rh/SiO2 was for the first time investigated in detail using multiproduct SSITKA. Based on SSITKA results, methanol and CH4 appeared to be produced on different active sites. It is possible that C2 products share at least one intermediate with CH4, but not with methanol. Moreover, C2 hydrocarbons are not likely to be formed from adsorbed acetaldehyde

Zeolites and related materials as catalyst supports for hydrocarbon oxidation reactions

Catalytic oxidation is a key technology for the conversion of petroleum-based feedstocks into useful chemicals (e.g., adipic acid, caprolactam, glycols, acrylates, and vinyl acetate) since this chemical transformation is always involved in synthesis processes. Millions of tons of these compounds are annually produced worldwide and find applications in all areas of chemical industries, ranging from pharmaceutical to large-scale commodities. The traditional industrial methods to produce large amounts of those compounds involve over-stoichiometric quantities of toxic inorganic reactants and homogeneous catalysts that operate at high temperature, originating large amounts of effluents, often leading to expensive downstream processes, along with nonrecovery of valuable catalysts that are loss within the reactant effluent. Due to the increasingly stringent environmental legislation nowadays, there is considerable pressure to replace these antiquate technologies, focusing on heterogeneous catalysts that can operate under mild reactions conditions, easily recovered, and reused. Parallelly, recent advances in the synthesis and characterization of metal complexes and metal clusters on support surfaces have brought new insights to catalysis and highlight ways to systematic catalysts design. This review aims to provide a comprehensive bibliographic examination over the last 10 years on the development of heterogeneous catalysts, i.e., organometallic complexes or metal clusters immobilized in distinct inorganic supports such as zeolites, hierarchical zeolites, silicas, and clays. The methodologies used to prepare and/or modify the supports are critically reviewed, as well as the methods used for the immobilization of the active species. The applications of the heterogenized catalysts are presented, and some case-studies are discussed in detail.info:eu-repo/semantics/publishedVersio

Microporous Zeolites and Related Nanoporous Materials: Synthesis, Characterization and Applications in Catalysis

Microporous zeolites and nanoporous materials are important from an academic and industrial research perspective. These inorganic materials have found application as catalysts in several industrial processes in oil refinery, petro-chemical reactions, fine chemicals, speciality, drug discovery and pharmaceutical synthesis, exhaust emission control for stationary and mobile engines and industrial wastewater treatment. The reasons for their versatile applications in several industrial processes are their unique properties of microporous zeolites and nanoporous materials such as uniform pores, channel systems, shape selectivity, resistance to coke formation, thermal and hydrothermal stability. Furthermore, the possibility to tune the amount and strength of Brønsted and Lewis acid sites and their crystal size, as well as the possibility of modification with transition and noble metals, are key to their success as efficient, high selectivity and stable catalysts

Monometallic cerium layered double hydroxide supported Pd-Ni nanoparticles as high performance catalysts for lignin hydrogenolysis

Monometallic cerium layered double hydroxides (Ce-LDH) supports were successfully synthesized by a homogeneous alkalization route driven by hexamethylenetetramine (HMT). The formation of the Ce-LDH was confirmed and its structural and compositional properties studied by XRD, SEM, XPS, iodometric analyses and TGA. HT-XRD, N-2-sorption and XRF analyses revealed that by increasing the calcination temperature from 200 to 800 degrees C, the Ce-LDH material transforms to ceria (CeO2) in four distinct phases, i.e., the loss of intramolecular water, dehydroxylation, removal of nitrate groups and removal of sulfate groups. When loaded with 2.5 wt% palladium (Pd) and 2.5 wt% nickel (Ni) and calcined at 500 degrees C, the PdNi-Ce-LDH-derived catalysts strongly outperform the PdNi-CeO2 benchmark catalyst in terms of conversion as well as selectivity for the hydrogenolysis of benzyl phenyl ether (BPE), a model compound for the alpha-O-4 ether linkage in lignin. The PdNi-Ce-LDH catalysts showed full selectivity towards phenol and toluene while the PdNi-CeO2 catalysts showed additional oxidation of toluene to benzoic acid. The highest BPE conversion was observed with the PdNi-Ce-LDH catalyst calcined at 600 degrees C, which could be related to an optimum in morphological and compositional characteristics of the support

Iron-based Nanomaterials in the Catalysis

Available data on catalytic applications of the iron-containing nanomaterials are reviewed. Main synthesis methods of nZVI, nano-sized iron oxides and hydroxides, core-shell and alloy structures, ferrites, iron-containing supported forms, and composites are described. Supported structures include those coated and on the basis of polymers or inert inorganic materials (i.e., carbon, titania or silica). Description of catalytic processes includes the decomposition reactions (in particular photocatalytic processes), reactions of dehydrogenation, oxidation, alkylation, C–C coupling, among a series of other processes. Certain attention is paid to magnetic recovery of catalysts from reaction systems and their reuse up to several runs almost without loss of catalytic activity

Acid catalyzed carbohydrate degradation and dehydration

Facile commercial production of versatile polyfunctional compounds from biomass constitutes a great challenge for establishing a sustainable chemical industry. One such example is the production of furfural and hydroxymethyl furfural via dehydration of pentoses and hexoses. Identified as primary building blocks in polymer industry, their massive production is highly desired, yet suffers from several problems, such as feedstock availability, low product yields due to excessive side reactions and lack of an industrially feasible heterogeneous catalyst. Organic acid functional groups incorporated onto mesoporous silica offer well defined catalytic sites beside their unique textural properties and therefore could be considered as promising catalysts. However, a rational approach for fine tuning of the catalyst to meet the reaction system requirements entails detailed understanding of the nature of the catalytic sites in condensed phase under similar conditions mimicking the reaction environment. For the characterization in condensed phase, a methodology was developed using potentiometric titration, and the acidic strength and total acid capacity of the organic acid functionalized materials were determined. Organic acid moieties of different strength were able to display their own acidity without being leveled in water, strongest being arene sulfonic group followed by propyl sulfonic, ethyl phosphonic and butyl carboxylic. When compared to literature, some discrepancy was noticed about the acidic strength of propyl sulfonic and arene sulfonic groups. Because most of these studies were focused on examining the interaction of the acidic group with a gas phase probe molecule, the effect of solvation was neglected. The effect of solvation on the acidic strength of these moieties was investigated via quantum chemical simulations. A change in the acidic strength trend was observed with the increasing number of water molecules, indicating that one-to-one interaction in the gas phase does not necessarily represent the interaction of the moiety with the solvent molecules. The difference in the acidic strength for these organic acid groups incorporated into mesoporous silica was not observed when they were tested for their activity on hexose and pentose dehydration due to poor hydrothermal stability of the materials at elevated temperatures. Doping of sulfated zirconia onto mesoporous silica materials was another alternative due to their high activity in cellobiose hydrolysis, but these materials did not provide hydrothermal stability either. Monosaccharide decomposition parameters with mesoporous silica materials could not be thoroughly validated with previously reported data due to the lack of systematic studies in literature. A systematic study with mineral and organic homogeneous acids of varying strength built the platform for catalyst comparison and revealed that different mechanisms were dominating for glucose decomposition in the presence of weak acids according to the pH value of the solution. Although lower acid concentration leads to higher selectivity toward HMF, this could not be considered as an industrially viable solution. Alternatively, addition of alkaline earth metals and appliance of pressure in the presence of acid catalyst activated the glucose ring and resulted in high HMF yields. Further enhancement was obtained by addition of an organic phase for HMF extraction. This process also allows for combining it with polysaccharides hydrolysis and one pot HMF production from biomass. By further optimization of the parameters, an industrially feasible process for HMF production can be achieved

Value-added Chemicals from Biomass by Heterogeneous Catalysis

I den samtidige debat om ressourceudnyttelse har anvendelsen af biomasse været diskuteret som en alternativ carbon-kilde til de fossile reserver med henblik på at reducere CO2-emissionen til atmosfæren. Erstatningen eller supplementet til de oliebaserede transportbrændstoffer gennem konversion af biomasse er allerede etableret. Fremstilling af kemikalier fra biomasse har haft ringere bevågenhed. Denne afhandling beskriver og evaluerer en søgen efter en alternativ konversionsrute, baseret på biomasseføde og under anvendelse af en heterogen katalysator, som er i stand til at omsætte føden til et merværdi-kemikalie. Projektarbejdet i denne forbindelse er udført med en tværfaglig tilgang omfattende fra fundamentale katalysatorundersøgelser, gennem eksperimenter, karakterisering og procesevalueringer til markedsanalyse. Rationalet herfor er søgt gennem aktiverne i den opnåede bæredygtige ressourceudnyttelse for sådan en proces og under hypotesen, at lønsomheden af processen, i sammenligning med de konventionelle teknologier, yderligere kan opnås gennem fordelen ved bevarelsen af kemiske C-C bindinger i biomasse-baserede føder. Med udgangspunkt i ethanol som eksempel på en biomasse-baseret føde, som har beholdt en C-C binding fra det oprindelige biomasse-udgangsstof, bliver aspekterne for at udnytte heterogen katalyse til dets omsætning til merværdi-kemikalier undeersøgt. Gennem en simpel analyse af kendte, men ikke-industraliserede procesruter, bliver ethanol til eddikesyre-ruten identificeret som én, der viser gode perspektiver. Inkorporeringen af en nyttig katalysator i en effektiv proces er afgørende for potentialet af den overordnede procesinnovation. En gruppe Cu baserede katalysatorer, som viser sig aktive i pågældende konversion, bliver identificeret i en forundersøgelseseksperimentrække. Under hensynet til handlefriheden bliver endvidere procesudviklingsmuligheder afdækket, baseret på de opnåede eksperimentelle vidnesbyrd, teori og proceselementer beskrevet i litteraturen (fortrinsvis patent-). Der bliver søgt beskyttelse af de relaterede opfindelser gennem indlevering af tre patentansøgninger. Afhandlingens vigtigste bidrag er afspejlet i den endelige konklusion, at en ethanol til eddikesyreproces og tilhørende katalysator, begge genstande for videreudvikling, er identificeret. Forståelsen af den katalytiske opførsel af udvalgte katalysatorer, Cu spinel (CuAl2O4) og Cu/SiO2, bliver opnået gennem karakterisering heraf såvel som målinger af aktivitet, selektivitet og stabilitet bl.a. i formålsudviklede testopstillinger. Gennem adskillige karakteriseringsanalyser (XAFS, XRPD, SEM, TEM, TPR, carbon analysis etc.) kan det konkluderes, at den hurtige deaktivering af Cu spinel katalysatoren skyldes dannelsen af højmolekylære kulholdige stoffer som dækker katalysatoroverfladen, katalyseret af sure alumina sites, der opstår under katalysatoraktiveringen. Denne forklaring er i overensstemmelse med adskillige observerede fænomener for katalysatoren. Cu/SiO2 - katalysatoren, som har en inert support, viser langt højere robusthed over for procesvariationer, men udviser umiddelbart en for lav katalytisk aktivitet set fra en industriel vinkel. Adskillige måder til forbedring af aktiviteten bliver belyst. F.eks. indikeres en aktivitetsafhængighed af Cu-krystalstørrelsen ved en sammenligning af aktivitet og XRPD analyser for nedknuste og hele katalysatorpiller. Der bliver udledt empiriske kinetiske modeller, i god overensstemmelse med de opnåede eksperimentelle data for Cu/SiO2-katalysatoren, for at understøtte etableringen af en forbedret økonomisk vurdering af den undersøgte proces. Ekstrapolation af de udledte modeller indikerer tilfredsstillende aktivitet i det industrielle trykområde. Cu/SiO2-katalysatoren er endvidere i stand til at klare delvist oxidative dehydrogeneringsbetingelser, som tillader betydelige procesforbedringer. Slutteligt bliver ethanol til eddikesyre processen sat i en større sammenhæng ved i et tilbageblik at revurdere de i arbejdet anvendte metoder, markedets indflydelse på processens chancer, konklusioner og forbedringsmuligheder for processen. Endeligt, i betragtning af nogle fremadrettede alternative procesmuligheder, gives mine konkluderende anbefalinger under hensynet til det oprindelige projektformål. Afhandlingens resultater viser, med udgangspunkt i et enkelt eksempel på biomassekonversion, at udnyttelsen af biomasse i produktionen af kemikalier er lovende fra et teknisk synspunkt. Men risikoen for markedsprisudsving, domineret af fossilt baserede kemikalier, stiller endvidere kriteriet om en pålidelig økonomisk margin. Derfor bør man under markedshensyn undersøge alternativer. I tillæg til de tekniske konklusioner forekommer det, at en tvær-disciplinær tilgang til procesinnovation er fordelagtig.In the contemporary debate on resource utilisation, biomass has been discussed as an alternative carbon source to fossil reserves in order to reduce the emission of CO2 to the atmosphere. The replacement or supplement of oil based transportation fuels through biomass based conversions has already been implemented. The subject on chemical production has received less attention. This thesis describes and evaluates the quest for an alternative conversion route, based on a biomass feedstock and employing a heterogeneous catalyst capable of converting the feedstock, to a value-added chemical. The project work to fulfil the above objective has been conducted with a multi-disciplinary approach ranging from fundamental catalyst research, through experiments, characterisation and process evaluation to market analysis. The motivation herein is sought in the assets of sustainable resource utilisation obtained for such a process and the hypothesis that process feasibility in comparison with the conventional synthesis gas based technologies may further be attainable, taking advantage of the conservation of chemical C-C bonds in biomass based feedstocks. With ethanol as one example of a biomass based feedstock, having retained one C-C bond originating from the biomass precursor, the aspects of utilising heterogeneous catalysis for its conversion to value added chemicals is investigated. Through a simple analysis of known, but not industrialised catalytic routes, the direct conversion of ethanol to acetic acid product is identified to show good perspectives. The nesting of a useful catalyst and an effective process is crucial to the potential of the overall process innovation. In a pre-screening study, a group of Cu based catalysts active in the conversion have been identified. Considering the freedom to operate, the prospects of process development are further identified through process calculations based on the experimental evidence attained, theory and the process elements described in literature (primarily patent-related). The protection of the process inventions made in relation to this is sought through the filing of three patent applications. The most important contributions of this thesis are reflected in the eventual conclusion that an ethanol to acetic acid process and a related catalyst, both subject to further development, are identified. The understanding of the catalytic behaviour of down-selected catalysts, Cu spinel (CuAl2O4) and Cu/SiO2, is obtained through characterisation as well as activity, selectivity and stability studies in appropriately developed experimental set-ups. Through numerous characterisation analyses (XAFS, XRPD, SEM, TEM, TPR, carbon analysis etc.) the rapid deactivation of the Cu spinel catalyst may be concluded to be attributed to the formation of high molecular carbonaceous compounds covering the catalytic surface, being catalysed by acidic alumina sites present during and after catalyst activation. This theory explains several phenomena observed for this catalyst. The Cu/SiO2 catalyst, having an inert support, shows far higher robustness to process variations, but immediately exhibits a too low activity from an industrial angle. Several means of improving its activity are elucidated. For example an activity dependence on the Cu crystal size is indicated by the comparison of the activity and XRPD analyses obtained for crushed and whole catalyst pellets. Empirical kinetic models, in good agreement with the experimental data obtained for the Cu/SiO2 catalyst, are developed in order to support the establishment of an improved economic evaluation of the investigated process. Extrapolation of the derived model to the industrial pressure regime indicates a satisfactory activity. The Cu/SiO2 catalyst is further able to withstand partly oxidative dehydrogenation conditions, allowing for immense process improvements. Finally, the ethanol to acetic acid process is put into a broader context, by reviewing the methods used in this work, the market influence on its fate, the conclusions and suggested improvements listed. Eventually, with an outlook on some alternative process possibilities, my recommendations are given under the consideration of the initial project objective. The results of the thesis, taking one example of biomass conversion, show that the utilisation of biomass in the production of chemicals by heterogeneous catalysis is promising from a technical point of view. But risks of market price excursions dominated by fossil based chemicals further set a criterion of a solid economic margin. Therefore, under market considerations other alternatives are to be investigated. In addition to the technical conclusions it appears that a multi-disciplinary approach to process innovation is advantageous