Kinetics of hydroformylation of 1-octene in ionic liquid-organic biphasic media using rhodium sulfoxantphos catalyst

Biphasic hydroformylation of 1-octene was performed using rhodium sulfoxantphos catalyst dissolved in [BuPy][BF4] ionic liquid. Preliminary experiments proved this system to retain the catalytic complex within the ionic liquid phase and to maintain a high selectivity towards the linear aldehyde (n:iso ratio of 30) over several cycles. Process parameter investigation showed a first order dependence of the initial rate with respect to the catalyst and 1-octene concentrations, but a more complex behavior with respect to hydrogen (fractional order) and carbon monoxide partial pressures (inhibition at high pressures). Different mathematical models were selected based on the trends observed and evaluated for data fitting. Also, rate models were derived from a proposed mechanism, using Christiansen matrix approach. To calculate concentrations of substrates in the catalytic phase as required by this kinetic modeling, solubility measurements were preformed for the gases (pressure drop technique), as well as for 1-octene and n-nonanal (thermogravimetry analysis)

Current State of the Art of the Solid Rh-Based Catalyzed Hydroformylation of Short-Chain Olefins

The hydroformylation of olefins is one of the most important homogeneously catalyzed processes in industry to produce bulk chemicals. Despite the high catalytic activities and selectivity’s using rhodium-based homogeneous hydroformylation catalysts, catalyst recovery and recycling from the reaction mixture remain a challenging topic on a process level. Therefore, technical solutions involving alternate approaches with heterogeneous catalysts for the conversion of olefins into aldehydes have been considered and research activities have addressed the synthesis and development of heterogeneous rhodium-based hydroformylation catalysts. Different strategies were pursued by different groups of authors, such as the deposition of molecular rhodium complexes, metallic rhodium nanoparticles and single-atom catalysts on a solid support as well as rhodium complexes present in supported liquids. An overview of the recent developments made in the area of the heterogenization of homogeneous rhodium catalysts and their application in the hydroformylation of short-chain olefins is given. A special focus is laid on the mechanistic understanding of the heterogeneously catalyzed reactions at a molecular level in order to provide a guide for the future design of rhodium-based heterogeneous hydroformylation catalysts

Rh-catalyzed carbonylation of disubstituted olefins: asymmetric catalysis, continuous flow and tandem hydroaminomethylation reaction

La present tesi doctoral tracta sobre la carbonilació asimètrica d'olefines disubstituïdes. S'hi descriu la importància de les reaccions de carbonilació d'alquens, especialment es detalla els resultats més recents en la hidroformilació asimètrica i hidroaminometilación d'olefines catalitzada per rodi, a més de la importància de la implementació de sistemes en flux continu per a la millora de l'eficiència de processos catalítics. En el capítol 3 es descriu la hidroformilació de norborneno en sistema tancat i en flux continu mitjançant catalitzadors heterogeneizados. Aquests han estat preparats mitjançant la immobilització de catalitzadors de rodi quirals sobre suports de carboni. En el capítol 4 es detalla la hidroaminometilación asimètrica d'acrilats catalitzada per complexos de rodi per a la síntesi de gamma amino èsters quirals. Aquesta investigació constitueix el primer exemple de hidroaminometilación asimètrica d'alquens catalitzada per un únic precursor de rodi. A més es descriuen els resultats obtinguts en l'estudi de la reactivitat del sistema catalític via experiments de ressonància magnètica nuclear d'alta pressió. Finalment, el capítol 5 presenta els resultats obtinguts en la hidroaminometilación regioselectiva d'acrilats catalitzada per complexos de rodi per a la síntesi de beta amino èsters. Es discuteixen les diferents optimitzacions realitzades, així com els diferents efectes observats quan es van usar amines primàries i secundàriesLa presente tesis doctoral trata sobre la carbonilación asimétrica de olefinas disustituidas. En ella se describe la importancia de las reacciones de carbonilación de alquenos, en especial se detalla los resultados más recientes en la hidroformilación asimétrica y hidroaminometilación de olefinas catalizada por rodio, además de la importancia de la implementación de sistemas en flujo continuo para la mejora de la eficiencia de procesos catalíticos. En el capítulo 3 se describe la hidroformilación de norborneno en sistema cerrado y en flujo continuo mediante catalizadores heterogeneizados. Estos han sido preparados mediante la immobilización de catalizadores de rodio quirales sobre soportes de carbono. En el capítulo 4 se detalla la hidroaminometilación asimétrica de acrilatos catalizada por complejos de rodio para la síntesis de gamma amino ésteres quirales. Esta investigación constituye el primer ejemplo de hidroaminometilación asimétrica de alquenos catalizada por un único precursor de rodio. Además se describen los resultados obtenidos en el estudio de la reactividad del sistema catalítico vía experimentos de resonancia magnética nuclear de alta presión. Finalmente, el capítulo 5 presenta los resultados obtenidos en la hidroaminometilación regioselectiva de acrilatos catalizada por complejos de rodio para la síntesis de beta amino ésteres. Se discuten las diferentes optimizaciones realizadas, así como los diferentes efectos observados cuando se usaron aminas primarias y secundarias.The current Ph. D. Thesis deals with the carbonylation of disubstituted olefins. The impact of the alkene carbonylation reactions is stressed; especially the most important results in asymmetric hydroformylation and hydroaminomethylation reported in the literature are described. Furthermore, a description of flow systems and the benefits of its implementation to catalytic processes are detailed. In Chapter 3 the rhodium catalyzed asymmetric hydroformylation of norbornene in batch and under flow conditions using heterogenized catalysts is described. In Chapter 4 it is detailed the rhodium catalyzed asymmetric hydroaminomethylation of acrylates for the efficient synthesis of chiral gamma-aminobutyric esters. This system constitutes the first example of asymmetric hydroaminomethylation of olefins catalyzed by one single rhodium precursor. Furthermore, the results obtained via high pressure NMR in the study of the reactivity of the catalytic systems are described. Finally, the Chapter 5 presents the results obtained in the rhodium catalyzed regioselective hydroaminomethylation of acrylates for the synthesis of beta-amino esters, as well as the different effects observed when primary and secondary amines area applied

Hydroformylation of synthetic naphtha catalyzed by a dinuclear gem-dithiolato-bridged rhodium(I) complex

This work focuses on the use of a gem-dithiolato-bridged rhodium(I) Rh 2(µ-S 2CBn 2)(cod) 2 complex (cod = 1,5-cyclooctadiene, Bn 2CS 2 2- = 1,3-diphenyl-2,2-dithiolatopropane) dissolved in toluene in the presence of monodentate phosphite P-donor ligand (P(OPh) 3) under carbon monoxide/hydrogen (1:1, syngas) atmosphere as an effective catalyst for hydroformylation of some olefins (oxo-reactions). The capability of this system to catalyze the hydroformylation of hex-1-ene, cyclohexene, 2,3-dimethyl-but-1-ene and 2-methyl-pent-2-ene and their quaternary mixture (synthetic naphtha) has been demonstrated. This innovative method to perform the in situ hydroformylation of the olefins present in naphthas to oxygenated products would be a promissory work for a future industrial catalytic process applicable to gasoline improving based on oxo-reactions. An important observation is that variation of CO/H 2 pressure (6.8-34.0 atm), temperature (60-80 oC), reaction time (2-10 h), rhodium concentration ((1.0-1.8)x10 -3 mol/L) affect hydroformylation reaction rates. Optimal conversion to oxygenated products were achieved under Rh = 1.8 x10 -2 mol/L, P(CO/H 2) = 34 atm (CO/H 2 = 1:1) at 80 oC for 10 h

Catalysis with porous MOFs: structure-catalytic property-relationships in the hydroformylation of olefins over Rh supported metal-organic frameworks

It deals with preparation, characterization, and catalytic testing of Rh supported catalysts based on MOFs using hydroformylation as a model reaction. The influence of the MOF support on the catalytic performance (Structure-Catalytic Property-Relationships) is emphasized. Different MOF structures and pore sizes were synthesized, Rh immobilized, characterized, and tested. Results show that single site catalysts are achieved. The catalytic performance is affected by the structure, texture, and porosity of the MOF support. The linker orientation is of importance leading to single-file diffusion

Synthesis of chiral furanoside diphosphinite and thioether-phosphinite compounds derived from d-(+)-xylose. Application as ligands in asymmetric catalytic processes

En els últims anys, la creixent demanda de compostos enantiomèricament purs (fàrmacs, agroquímics, additius.) ha impulsat el desenvolupament de la catàlisi asimètrica, sobretot emprant compostos organometàl·lics quirals com a catalitzadors. En aquest context, la síntesi de nous lligands quirals és essencial per descobrir bons sistemes catalítics en catàlisi asimètrica. Els sucres són una font important de lligands per l'elevada disponibilitat i baix preu. A més, són compostos altament funcionalitzats amb centres estereogènics. Això permet la síntesi de sèries sistemàtiques de lligands amb l'objectiu d'obtenir altes activitats i selectivitats per cada reacció en particular.Aquesta tesi s'ha centrat en la síntesi de compostos derivats de la D-(+)-xilosa i l'aplicació com a lligands de catalitzadors homogenis quirals en quatre reaccions asimètriques d'interès industrial: hidrogenació, substitució al·lílica, addició 1,4 i hidroformilació. Per assolir aquest objectiu s'ha plantejat la síntesi de dues famílies de compostos: difosfinits i tioèter-fosfinit (figura 1). Els difosfinits es diferencien en la configuració del carboni-3 de l'esquelet furanòsid (els dos esquelets resultants són xilofuranòsid i ribofuranòsid). Els tioèter-fosfinits es diferencien dels anteriors per la introducció d'un grup tioèter al carboni-5 de l'anell furanòsid i contenen tres grups tioèters amb diferents propietats electròniques i estèriques. Figura 1. Compostos sintetitzats a partir de la D-(+)-xilosa.Després de la introducció (capítol 1) i els objectius (capítol 2), al capítol 3 es discuteix la síntesi i caracterització de les dues famílies de compostos. També s'estudia la coordinació d'aquests compostos a Rh i Ir, la reactivitat respecte a l'hidrogen i l'aplicació en la hidrogenació d'olefines proquirals.Per sintetitzar els compostos difosfinit i tioèter-fosfinit s'ha realitzat un ampli estudi explorant i avaluant diferents condicions de reacció. Els compostos difosfinit s'han preparat per reacció del corresponent diol amb clorur de difenilfosfina en presència de piridina i 4-dimetilaminopiridina. Els compostos tioèter-fosfinits s'han obtingut a partir del corresponent tioèter-alcohol per reacció amb clorur de difenilfosfina en presència de piridina i 4-dimetilaminopiridina. Els compostos intermedis diols i tioèter-alcohols s'han sintetitzat prèviament seguint rutes descrites a la bibliografia a partir de la D-(+)-xilosa. Els compostos s'han caracteritzat per espectroscòpia de ressonància magnètica nuclear (RMN) monodimensional de 1H, 13C i 31P i bidimensional de 13C-1H i 31P-1H.Aquests compostos s'han fet reaccionar amb [M(cod)2]BF4 (M= Rh i Ir, cod= 1,5-ciclooctadiè). Els complexos organometàl·lics resultants [M(cod)(P-P)]BF4 i [M(cod)(P-SR)]BF4 (P-P=difosfinit i P-SR=tioèter-fosfinit) s'han caracteritzat per RMN monodimensional de 1H, 13C i 31P i bidimensional de 1H-1H, 13C-1H i 31P-1H. La caracterització dels complexos M/difosfinit ha mostrat que tots, excepte el complex Ir/difosfinit amb esquelet xilofuranòsid, presenten un únic isòmer. La caracterització dels complexos M/tioèter-fosfinit ha mostrat la presència d'un únic diastereoisòmer en què el substituent del sofre té una disposició pseudoaxial, que és important per obtenir una elevada enantioselectivitat en hidrogenació asimètrica. L'addició d'hidrogen als complexos d'iridi/tioèter-fosfinit ha permès formar les espècies cis-dihidruriridi (III) en les quals el substituent del sofre manté la disposició pseudoaxial.Els sistemes M/difosfinit i M/tioèter-fosfinit (M= Rh i Ir) s'han provat com a catalitzadors quirals en la reacció d'hidrogenació asimètrica d'olefines proquirals. Els sistemes M/disfosfinit han proporcionat elevades activitats i excessos enantiomèrics de fins al 81%. S'ha observat un important efecte de la configuració del carboni-3 de l'esquelet furanòsid, del metall i del substrat que s'ha d'hidrogenar. Així, les millors enantioselectivitats s'obtenen en la hidrogenació del N-acetoamidoacrilat de metil amb el sistemes Rh/ribofuranòsid i Ir/xilofuranòsid. Els sistemes M/tioèter-fosfinit han proporcionat elevades activitats i millors enantioselectivitats (96%) que els sistemes M/difosfinit. Els resultats mostren que l'excés enantiomèric depèn de les propietats estèriques del substituent del grup tioèter, del metall i del substrat. Les millors enantioselectivitats s'obtenen en la hidrogenació del N-acetoamidoacrilat de metil i del N-acetoamidocinamat de metil amb el sistema de rodi que conté el lligand amb el substituent isopropil en la funció tioèter. El capítol 4 descriu l'ús dels compostos difosfinit i tioèter-fosfinit com a lligands en reaccions de substitució al·lílica asimètrica (alquilació i aminació) catalitzades per pal·ladi. Concretament s'ha estudiat la reacció d'alquilació al·lílica de dos substrats amb propietats estèriques diferents: el substrat lineal rac-1,3-difenil-3-acetoxi-1-propè i el substrat cíclic rac-3-acetoxiciclohexè. El sistemes Pd-difosfinit han presentat bones activitats però baixa enantioselectivitat (fins al 31%). Els resultats indiquen que la configuració del carboni-3 de l'esquelet furanòsid controla el sentit de l'enantioselectivitat i que l'atac nucleofílic té lloc en posició trans al grup fosfinit unit al carboni-5 de l'esquelet furanòsid. Els sistemes Pd/tioèter-fosfinit han presentat millors activitats i enantioselectivitats més grans (93%) que els sistemes Pd/difosfinit. Els resultats mostren que l'excés enantiomèric depèn de les propietats estèriques del substituent del grup tioèter i del substrat. Així, les millors enantioselectivitats s'han assolit en la substitució al·lílica del substrat lineal amb el sistema de Pd que conté el lligand tioèter-fosfinit amb el grup voluminós isopropil. Els resultats també indiquen que l'atac nucleofílic, a diferència dels sistemes Pd/difosfinit, té lloc en posició trans al carboni al·lílic unit al grup fosfinit (carboni-3). D'altra banda, aquests lligands són més actius en alquilació al·lílica que en aminació al·lílica. El capítol 5 descriu l'aplicació dels compostos difosfinits i tioèter-fosfinits com a lligands en la reacció d'addició 1,4 de compostos organometàl·lics a la 2-ciclohexenona catalitzada per coure. S'han obtingut bones enantioselectivitats (72%), elevades activitats (TOF > 1225 mols producte x (mol precursor catalític x h)-1) i excel·lents regioselectivitats en el producte d'addició 1,4 (100%)). Els resultats mostren que l'activitat i l'enantioselectivitat depenen del tipus de grup funcional unit al carboni-5 de l'esquelet furanòsid, de les propietats estèriques del substituent tioèter, del precursor de catalitzador i de l'agent alquilant. Les millors enantioselectivitats s'obtenen amb el sistema Cu/tioèter-fosfinit que conté el grup isopropil. No obstant això, l'activitat és millor amb els sistemes Cu/difosfinit. La utilització d'AlEt3 com a agent alquilant condueix a millors activitats però pitjors enantioselectivitats que el ZnEt2. El capítol 6 exposa l'aplicació dels compostos difosfinits amb esquelet furanòsid com a auxiliars quirals en la reacció d'hidroformilació asimètrica de vinilarens catalitzada per rodi. Aquests sistemes han proporcionat elevades regioselectivitats en l'aldehid ramificat (99%) i moderats excessos enantiomèrics (fins al 63%). La presència de substituents para-metoxi i naftil al substrat té un efecte positiu sobre l'enantioselectivitat. Per primera vegada, s'ha determinat l'estructura de les espècies formades sota condicions d'hidroformilació amb lligands difosfinit mitjançant infraroig i RMN a alta pressió. L'estudi indica la presència d'un únic diastereoisòmer [HRh(P-P)(CO)2] on el lligand difosfinit es coordina en una estructura de bipiràmide trigonal en forma equatorial-equatorial. No obstant això, aquesta forma diastereoisomèrica no permet assolir una enantioselectivitat elevada.In the last years, the growing demand of enantiomerically pure compounds (pharmacs, agrochemicals, additives...) has captured the interest of asymmetric catalysis. Asymmetric processes catalyzed by chiral transition-metal complexes have found many applications in this field. In this context, the synthesis of new chiral ligands is important to develop good catalytic systems in asymmetric catalysis. Carbohydrates have many advantages: they are readily available, are highly functionalized and have several stereogenic centers. This enables series of chiral ligands to be synthesized in the search for high activities and selectivities for each particular reaction.This thesis has focused on the synthesis of compounds derived from D-(+)-xylose and their application as ligands of chiral homogeneous catalyst in four asymmetric industrial processes: hydrogenation, allylic substitution, 1,4-addition and hydroformylation. Thus, new diphosphinite and thioeter-phosphinite compounds have developed (figure 1). Diphosphinites have the opposite configuration at C-3 (two backbones are xylofuranoside and ribofuranoside). Thioether-phosphinites have a thiother moiety at C-5 bearing substituents with different steric and electronic properties. Figura 1. Compounds synthetized from D-(+)-xylose.After the introduction (chapter 1) and the objectives (chapter 2), chapter 3 contains the synthesis and characterization of the two families of compounds. This chapter also discusses the characterization of their Rh(I) and Ir(I) catalytic precursors and their application in the asymmetric hydrogenation of prochiral olefins.Diphosphinite and thioether-phosphinite compounds have been synthesized from the corresponding alcohols. The reaction of diols with chlorodiphenylphosphine in the presence of pyridine and 4-(dimethylamino)-pyridine has provided the corresponding phosphinite ligands. The reaction of thioether-alcohols with chlorodiphenylphosphine in the presence of pyridine and 4-(dimethylamino)-pyridine has provided the corresponding thioether-phosphinite ligands. Diol and thioether-alcohol intermediates have been prepared on a large scales from D-(+)-xylose using standard procedures. Diphosphinites and thioether-phosphinites have been characterized by 1H, 13C and 31P and 13C-1H i 31P-1H MNR spectroscopy.The reaction of these compounds with [M(cod)2]BF4 (M = Rh and Ir, cod = 1,5-ciclooctadiene) has led to [M(cod)(P-P)]BF4 and [M(cod)(P-SR)]BF4 (P-P = diphosphinite and P-SR = thioether-phosphinite) complexes. These complexes have been characterized by 1H, 13C and 31P and 13C-1H i 31P-1H MNR spectroscopy.The characterization of M/diphosphinite complexes has showed that all, except Ir/diphosphinite complex with xylofuranoside backbone, have only one isomer. The characterization of M/thioether-phosphinite complexes has indicated that only one diastereomer, with pseudoaxial location of the sulfur substituents, is present in solution. Adding hydrogen to the iridium complexes has given cis-dihydridoiridium(III) complexes with pseudoaxial location of the sulfur substituents.The M/diphosphinite and M/thioether-phosphinite systems have been tested as chiral catalysts in the asymmetric hydrogenation of prochiral olefins. Enantiomeric excesses of up to 81% with moderate to high activities have been obtained with M/diphosphinite systems. Our results have shown that enantioselectivity is dependent on the absolute configuration of the C-3 stereocenter of the carbohydrate bakcbone, on the metal source and on the substrate. Enantiomeric excesses of up to 96% with good activities have been obtained with M/thioether-phosphinite systems. Our results have shown that enantioselectivity depends on the steric properties of the substituent in the thioether moiety, the metal source and the substrate structure.Chapter 4 reports the use of dihosphinite and thioether-phoshinite compounds as ligands in the palladium-catalyzed asymmetric allylic substitution reactions (alkylation and amination) of hindered linear and unhindered cyclic substrates. The use of diphosphinite ligands has provided good activity but low enantioselectivity (ee's up to 31%). Our results have indicated that the absolute configuration at carbon C-3 of the carbohydrate backbone controlles the sense of enantioselectivity and that the nucleophilic attack takes place trans to the phosphinite moiety attached to C-5. The Pd/thioether-phosphinite systems have led to best activities and enantioselectivities (ee's up to 93%) than the Pd/diphosphinite systems. Our results have shown that enantiomeric excesses depend on the steric properties of the substituent in the thioether moiety and the structure of substrate. Our results have showed that the nucleophilic attack takes place trans to the phosphinite moiety attached to C-3. Moreover, these ligands are more actives in allylic alkylation than allylic amination.Chapter 5 contains the application of diphosphinite and thioether-phoshinite compounds as ligands in the asymmetric copper-catalyzed asymmetric 1,4-addition to 2-cyclohexenone. Good enantioselectivities (ee's up to 72%), high activities (TOF > 1225 mol product x (mol catalytic precursor x h)-1) and excellent regioselectivities in 1,4 product (100%) have been obtained. Our results show that activity and selectivity (chemo- and enantioselectivity) depend strongly on the type of functional group at C-5 position of the carbohydrate backbone, the steric properties of the substituent in the thioether moiety, the catalyst precursor and the alkylating agent. The best enantioselectivities have been obtained with Cu/thioether-phosphinite system containing isopropyl substituent. However, activity is better with Cu/diphosphinite systems. The use of AlEt3 as alkylating agent has led to better activities but worse enantioselectivities than the use of ZnEt2.Chapter 6 discuss the application of diphosphinite compounds as chiral auxiliares in the rhodium-catalyzed asymmetric hydroformylation of vinyl arenes. These catalytic systems have led to high regioselectivities in the branched aldehyde (99%) and moderate enantiomeric excesses (up to 63%). The results have shown a remarkable substrate effect on enantioselectivity. Thus, the presence of para-methoxy and naphthyl substituents in the substrate has a positive effect on enantioselectivities. For the first time, the structure in solution of the species formed under hydroformylation conditions with diphosphinite ligands has been determined. The characterization of these rhodium complexes by NMR techniques and in situ IR spectroscopy have shown that the hydridorhodium dicarbonyl species exist in one diastereosiomeric equatorial-equatorial form. However, this strong coordination preference does not allow high enantioselectivity

Hydroformylation of Higher Olefins Using Radium Phosphite Complex Catalyst

Hydroformylation of olefins with CO and Hz at total pressure of IS to 50 bar and temperature of 80 to l20°C, in presence of rhodium (Rh)-based homogeneous catalysts for production of aldehydes has demonstrated high yields and selectivity. Rh-based catalysts are expensive and the commercial viability of a process that uses such catalysts substantially depends on the efficiency of catalyst recovery and product separation. In this work, a novel temperature dependent multi-component solvent (TMS) or 'thermomorphic solvent' system has been used as the reaction medium to investigate hydroformylation of two higher olefins - 1-octene and 1-dodecene - to synthesize the corresponding aldehydes at a lower pressure of 15-25 bar and temperature of 80 to 100°C. Such a solvent mixture changes thermally from biphasic to monophasic with distribution of the products and of the catalyst in the non-polar and polar phases thus simplifying the process of separation and recycling of the catalyst. A TMS- system consisting of three components - propylene carbonate (PC), ndodecane and 1,4-dioxane was used in this study. The presence of 1,4-dioxane imparts the thermomorphic character to the solvent mixture. For a gas-liquid reaction, the solubility of the reactant gas in the liquid medium is an important parameter required for the interpretation of reaction kinetics. Therefore experimental measurement of solubility of the gaseous reactants - CO and Hz - in the individual components of the solvent as well as in their mixtures was performed up to a pressure of 1.5 MPa and temperature range of 298-343 K. The effects of solvent composition, partial pressures of the gaseous reactants - CO and Hz, reaction temperature and catalyst loading on the rate, yield and selectivity of the linear aldehydes were also investigated. At a reaction temperature of 363 K and total pressure of 1.5 MPa and 0.68 mM HRh(CO)(PPh3)3, the conversion of 1- octene and the yield of aldehyde were 97 % and 95 %, respectively. The aldehyde product was recovered in the non polar phase whereas the catalyst remained in the polar phase with low catalyst loss of 3 %. With a reaction-time of 2 h and a selectivity of 89 %, this catalytic system can be considered as highly reactive and selective. The rate was found to be first order with respect to catalyst, 1-octene and PH, . The rate vs. Pco resembled a typical case of substrate inhibited kinetics. Hydroformylation of Higher Olefins Using Radium Phosphite Complex Catalys

Catalytic carbonylative functionalization of multiple carbon-carbon bonds

Diese Arbeit ist hauptsächlich auf die carbonylierende Funktionalisierung ungesättigter organischer Substrate in Gegenwart homogener Katalysatoren gerichtet. Speziell werden sowohl Alkoxycarbonylierungs- und Amino-carbonylierungsreaktionen als auch Hydroformylierungen von Alkinen, Alkenen und 1,3- Dienen präsentiert. Die resultierenden α,β-ungesättigten Aldehyde, gesättigte Ester und Amide, β,γ-ungesättigte Ester und Amide sind wichtige Zwischenprodukte für die organische Synthese und für die chemische Industrie

Towards a Benign and Viable Rhodium Catalyzed Hydroformylation of Higher Olefins: Economic and Environmental Impact Analyses, Solvent Effects and Membrane-based Catalyst Separation

Researchers at the Center for Environmentally Beneficial Catalysis (CEBC) had previously reported a novel rhodium-based hydroformylation process concept based on the use of CO2-expanded liquids (CXLs) to intensify rates and obtain higher linear/branched aldehydes selectivity at relatively mild temperatures (30-60 °C) and pressures (~4 MPa). This dissertation continues investigations aimed at addressing the fundamental and practical issues associated with this concept. ReactIR studies of Rh/triphenylphosphine-catalyzed 1-octene hydroformylation, complemented by microkinetic and reactor modeling investigations revealed that the intrinsic kinetic rate constants are of similar magnitude with or without CO2 addition to the reaction mixture. This implies that the enhanced reaction rate observed in CXL is due to the increased hydrogen solubility in that medium. Environmental impact analysis revealed that the overall toxicity index for the CEBC process is approximately 40 times less than the Exxon process against which the CEBC process was benchmarked. Economic analysis of the CXL concept revealed that at an aldehyde production rate of 19,900 kg / (kg Rh h), 99.8% rhodium has to be recovered per pass for the CEBC process to be competitive with the Exxon process. Assuming a similar hydroformylation turnover frequency, rhodium recovery levels that exceed this criterion for economic viability were successfully demonstrated in a membrane-based nano/ultra-filtration reactor system using polymer supported phosphorus ligands, synthesized and provided by researchers from the Department of Chemistry. During continuous filtration of a toluene-based solution containing polymer-supported Rh complexes, the Rh and P concentrations in the permeate, quantified using ICP analysis, were on the order of a few tens of ppb. During continuous 1-octene hydroformylation studies in the membrane reactor at a syngas pressure of 0.6 MPa and 60 °C, the 1-octene conversion and product (mostly aldehydes) concentrations reached a steady state with the Rh concentrations in the permeate stream being lower than 120 ppb. However, the conversions and product concentrations during the continuous run are lower than those obtained in a batch ReactIR under identical operating conditions. This is attributed to syngas starvation in the membrane reactor that might be caused by inadequate mixing. In complementary investigations, it was found that the dissolution of CO2 in the organic phase (to create CO2-expanded liquids) decreases the viscosities of the mixtures with increasing CO2 pressure. This offers an opportunity to enhance mixing and also tune the membrane flux so as to increase the throughput of the membrane filter. The demonstrated technology concept, when fully optimized, should find applications in a variety of other applications in homogeneous catalysis, including hydrogenation and carbonylation of conventional and biomass-based substrates

Greener Hydroformylation with Nanofilterable Rhodium Catalysts in A Stirred Membrane Reactor

Hydroformylation for producing industrial chemical intermediates such as aldehydes and alcohols from olefinic substrates is a 15 billion lb/year industry and a potential route for increasing the carbon chain of light olefins such as ethylene and propylene to produce longer chain olefins. Novel, resource-efficient technologies that conserve feedstock and energy while producing the desired product continue to be interest to industry. This dissertation advances a novel continuous reactor concept involving gas-expanded liquids and nanofilterable catalysts with potential for practical viability. It has been shown by previous researchers in our group that the use of simple homogeneous Rh/TPP catalyst for 1-octene hydroformylation in CO2-expanded liquid (CXL) media provides exceptional TOF (~316 h-1) and regioselectivity (n/i ~9) at mild pressure (~40 bar) and temperature (30-60 °C) when compared to conventional media. Systematic phase equilibrium and reaction studies performed in this dissertation show that CXLs provide a way of increasing (i.e., tuning) H2/CO ratio in the liquid phase at fixed syngas feed composition, low syngas partial pressures (i.e. avoiding syngas inhibition) and mild conditions (40-60 °C, tens of bars). A novel process concept for continuous hydroformylation in CXLs was demonstrated using bulky phosphite ligands that are effectively retained in the stirred reactor by a nanofiltration membrane. The reactor was operated at 50 °C with a syngas pressure of 6 bar to avoid CO inhibition of reaction rate and selectivity. The nanofiltration pressure was provided by ~32 bar CO2 that also created CXL phase resulting in enhanced turnover frequency (~340 h-1), aldehydes selectivity (>90%) and high regioselectivity (90%) and high regioselectivity (n/i ~8) at nearly steady operation for up to 50 h (cumulative TON of 17,680). Further, the use of pressurized CO2 also reduced the viscosity of the conventional liquid phase by 30 to 50% thereby improving the mass transfer properties. Constant permeate flux was maintained during the 50 h run with Rh leakage being less than 0.5 ppm. Novel Rh complex catalysts bound to soluble versions of inexpensive functionalized polysiloxanes ligands were also investigated for the hydroformylation of higher olefins (C5+) to enable nanofiltration in a continuous membrane reactor. Polysiloxanes containing two different functional groups (amine- and phosphine-) were used for Rh complexation. Both types of Rh complexes, when tested in batch and continuous hydroformylation experiments, show good activity and chemoselectivity for a variety of olefinic substrates. The phosphine-functionalized ligand exhibited higher activity (TOF = 165 h-1) than the amine-functionalized one (TOF = 17 h-1) at 6 bar and 50 °C. Continuous operation with Rh complexes (with the phosphine-functionalized ligand) lasting several days in a stirred reactor equipped with nanofiltration membrane showed steady hydroformylation activity (TOF = 103 h-1; cumulative TON = 12,240 after 120 hours) and high chemoselectivity ( 91%) towards the aldehydes. The Rh concentrations in the reactor effluent were less than a few ppm, which can be easily recovered by absorption and exceeds the economic viability criterion established by earlier work in our group. This technology concept has potential applications in homogeneous catalytic processes to improve resource utilization and catalyst containment for practical viability