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Sodium ethoxide, a cost-effective catalyst, completely outperforms the hitherto studied catalysts making large-scale PET depolymerization processes possibly far more sustainable.

Aqueous hydroaminomethylation (HAM) is an atom economical route for the efficient production of amines in one reaction step, starting from basic chemicals like alkenes. Herein we present the first successful establishment of a continuous process for HAM in an aqueous multiphase system. The green mass transfer agents randomly methylated-β-cyclodextrins (CD) enabled the catalytic system consisting of rhodium/sulfoXantphos to achieve high yields of up to 70% with selectivities of up to 80% in several continuous experiments with a total run time of more than 220 h. The key here is that water and products have large polarity differences, but the reaction still proceeds effectively due to the addition of cyclodextrin, which made the application of solvents obsolete. The main achievements in this way were the investigation of the influence of the randomly methylated-β-cyclodextrin concentration on the reaction rate and the selectivity in batch studies and finding promising operating points in the first continuous experiments. In a final experiment, the separation temperature was investigated. It was shown that the catalyst loss in the product phase is enormously small at 0.003% h−1 of the initial mass (0.24% in total), which is the lowest ever reported value for the HAM on this scale. Within a run time of 78 hours, 2.87 kg of tertiary amine were produced using only 0.2 g (>14 000 : 1) of transition metal, while the loss of rhodium per kg of product produced was mostly around 0.15 mg kg−1, suggesting possible economical applicability. 25;9

For the first time, palladium-catalyzed carbonylative telomerization enables the one-step synthesis of mixed carboxylic anhydrides directly from butadiene. These anhydrides are versatile intermediates and were used to form amides.

Glycolysis of post-consumer polyethylene terephthalate (PET) waste is a promising chemical recycling technique, back to the monomer, bis(2-hydroxyethyl) terephthalate (BHET). This work presents sodium methoxide (MeONa) as a low-cost catalyst for this purpose. BHET product was confirmed by gas chromatography-mass spectrometry (GCMS), Nuclear Magnetic Resonance (NMR) Spectroscopy, melting point, and Differential Scanning Calorimetry (DSC). It was shown, not surprisingly, that PET conversion increases with the glycolysis temperature. At a fixed temperature of 190 °C, the response surface methodology (RSM) based on the Box-Behnken design was applied. Four independent factors, namely the molar ratio of PET: MeONa (50–150), the molar ratio of ethylene glycol to PET (EG: PET) (3–7), the reaction time (2–6 h), and the particle size (0.25–1 mm) were studied. Based on the experimental results, regression models as a function of significant process factors were obtained and evaluated by analysis of variance (ANOVA), to predict the depolymerization performance of MeONa in terms of PET conversion. Coefficient of determination, R2 of 95% indicated the adequacy for predicted model. Afterward, the regression model was validated and optimized within the design space with a prediction of 87% PET conversion at the optimum conditions demonstrating a deviation of less than 5% from predicted response. A van ‘t Hoff plot confirmed the endothermic nature of the depolymerization reaction. The ceiling temperature (TC = 160 °C) was calculated from Gibbs’ free energy. A kinetic study for the depolymerization reaction was performed and the activation energy for MeONa was estimated from the Arrhenius plot (EA = 130 kJ/mol). The catalytic depolymerization efficiency of MeONa was compared under similar conditions with widely studied zinc acetate and cobalt acetate. This study shows that MeONa’s performance, as a glycolysis catalyst is promising; in addition, it is much cheaper and environmentally more benign than heavy metal salts. These findings make a valuable contribution towards the chemical recycling of post-consumer PET waste to meet future recycling demands of a circular economy.

Solvents have an enormous impact on yield and turnover of chemical reactions in complex media. There is, however, a lack of consistent model-based tools to a priori identify the appropriate solvent...

A reactive ionic liquid was successfully applied in the homogeneous ruthenium-catalyzed alcohol amination for the first time. Through detailed investigation of the phase behavior and the applicatio...

We present the development of catalytic auto-tandem reactions into continuous flow processes on the example of homogeneously catalyzed hydroaminomethylation (HAM, consisting of hydroformylation and...

Homogeneous transition metal catalysts allow for high selectivity at mild reaction conditions. However, very high recoveries of the precious catalyst are decisive for the development of economic processes, especially in case of reactions with an atom economy below 100% since co-products and their potential accumulation have to be considered. To address this issue, an innovative process concept is investigated, which exploits thermomorphic multiphase systems combined with organic solvent nanofiltration for homogeneous catalyst recovery and co-product removal. In this concept, the reaction takes place at elevated temperature in a homogeneous liquid phase, while the reactor effluent is cooled down, inducing a phase split. This allows for the separation of a product-rich non-polar and a catalyst-rich polar phase that is recycled into the reactor. The current article investigates this concept considering a reductive amination reaction as case study based on an experimental membrane screening and a model-based evaluation. DuraMem 150 (T1) proved to be the best membrane for all tested solvents as catalyst ligand rejections higher than 99% and a removal of the co-product water were achieved. The model-based evaluation indicated a final OSN-process of three stages for the solvent methanol and the requirement of a subsequent solvent recovery that is realized by distillation.

Transmission infrared in situ measurement technique was used to assess its feasibility for real-time process analysis. In particular, the advanced chemometric analysis by band-target entropy minimi...

For the first time, the reactive ionic liquid N,N-dimethyl ammonium N,N-dimethyl carbamate (dimcarb) was used as a polar solvent in the palladium-catalyzed telomerisation of the renewable monoterpene β-myrcene. By doing so, it was possible to avoid any volatile organic solvents. Moreover, the special decomposition behaviour of the reactive ionic liquid dimcarb could be exploited to the extent that dimethyl amine was used as a reagent in the reaction. Accordingly, non-symmetrical C20-chain dimethyl amines were produced from β-myrcene and dimethylamine liberated by dimcarb, achieving selectivities higher than 80%. Detailed investigations revealed the thermomorphic behaviour of the reaction mixture consisting only of dimcarb, β-myrcene and the catalytic system. The advantageous temperature-dependent phase behaviour resulted in one liquid phase occurring at the reaction temperature and two liquid phases upon cooling. Consequently, a virtually pure organic product phase could be separated from the polar catalyst-containing dimcarb phase. Immobilization of the catalyst in the polar reactive ionic liquid phase was ensured by the use of sulfonated triphenylphosphine derivatives. Subsequently, the separated catalyst-containing dimcarb phase was successfully reused in 14 consecutive recycling runs with only minimal leaching of both the catalyst and dimcarb, reaching a total turnover number of 12 000.

For the first time, the successful application of the homogeneously catalyzed reductive amination in a thermomorphic multiphase system (TMS) and the first reported scale-up of this reaction into a ...

Over the past 20 years, thermomorphic multiphase systems (TMS) have been used as a versatile and elegant strategy for the recovery and recycling of homogeneous transition-metal catalysts, in both batch-scale experiments and continuously operated processes. TMS ensure a homogeneous reaction in a monophasic reaction mixture at reaction temperature and the recovery of the homogeneous transition-metal catalyst through liquid-liquid separation at a lower separation temperature. This is achieved by using at least two solvents, which have a highly temperature-sensitive miscibility gap. The suitability of commercially available solvents makes this approach highly interesting from an industrial point of view. For the first time, herein, all studies in the area of TMS are reviewed, with the aim of providing a concise and integral representation of this approach for homogeneous catalyst recovery. In addition to the discussion of examples from the literature, the thermodynamic fundamentals of the temperature-dependent miscibility of solvents are also presented. This review also gives key indicators to compare different TMS approaches, for instance. In this way, new solvent combinations and in-depth research, as well as improvements to existing approaches, can be addressed and promoted.

Nanosized polyhedral oligomeric silsesquioxanes (POSS) have been employed as molecular weight enlarged structures for different purposes owing to their ease of synthesis and modification. In this work, the commercially available compound octaphenyl-POSS has been modified with chlorosulfonic acid to obtain multifunctional acidic materials (H-Sulfo-POSS) with different degrees of functionality in the structure. The synthesized materials have been characterized by ion exchange capacity, degree of sulfonation, 1H-NMR, ATR-IR spectroscopy and SEM. These H-Sulfo-POSS nanocomposites were then applied to the acetalization of glycerol with 2-butanone to yield the corresponding ketal, which is a product of interest as an oxygenate fuel additive. The catalytic activity in dynamic experiments of the H-Sulfo-POSS (2601 h−1) material with the highest degree of sulfonation was even higher than that shown by the molecular catalyst para-toluene sulfonic acid (PTSA) (2256 h−1) and better than Amberlyst 36 (213 h−1); however, upon recycling by centrifugation of the catalyst, the activity of this material was not very stable. On the other hand, the material with the lowest degree of sulfonation showed not only higher activity than Amberlyst 36, but also very stable activity after reutilization throughout 10 runs.

International audience; Hydroaminomethylation (HAM) is a highly efficient homogeneously catalyzed autotandem reaction converting alkenes into valuable amine products with water being the only coproduct. This work reports for the first time the scale-up of the highly regioselective HAM of 1-decene with diethylamine for a potential continuous process application in a green and sustainable aqueous biphasic medium. The catalytic system Rh/SulfoXantphos and randomly methylated β-cyclodextrin (RAME-β-CD) were herein dissolved in the plain aqueous phase. The addition of cyclodextrins as a green mass transfer agent remarkably increases the reaction rate as well as the selectivity toward linear amines, but they can also support solid content precipitation in this reaction system due to up-scaling effects. Therefore, parameters such as catalyst concentration, organic volume fraction, cyclodextrin concentration, and recyclability were investigated regarding the stability and activity of the system. Especially the organic volume fraction had a decisive influence on solid content precipitation. High regio- and chemoselectivities of 35 and 82%, respectively, at nearly full conversion were achieved toward the linear product amine. The catalytic system was further recycled in batch and scaled up into a 2100 mL autoclave without loss in activity and selectivity. Finally, a continuous process concept was proposed for an extensive investigation regarding long-term stability of the catalytic system.

For the first time, randomly methylated β-cyclodextrin was applied as the mass transfer agent in a continuous process. Considering the example of the Rh-catalyzed hydroformylation of 1-decene, process development was shown, where cyclodextrin was used together with a catalyst system that was continuously recovered and recycled using an aqueous biphasic system. In initial experiments, water-soluble and commercially available Rh/TPPTS and Rh/sulfoxantphos catalyst systems were scaled up from 50 ml into 1000 ml high-pressure autoclave systems to demonstrate their scalability. Both these systems were compared, and they afforded excellent chemoselectivity (>99%) toward the desired linear aldehyde product. In particular, higher regioselectivity (up to 31) was achieved for the Rh/sulfoxantphos system. Investigations regarding the long-term stability of the mass transfer agent and both catalyst systems were carried out in a continuously operated miniplant process. It was shown that the process could be successfully operated under the steady state for over 200 h with chemoselectivity of >97% toward the desired aldehyde product. Simultaneously, extremely low Rh leaching (total: 0.59%) was observed over the entire period of 200 h.

An alternative strategy for the Rh-catalysed hydroformylation of technical-grade methyl oleate in aqueous-media has been developed. This is achieved with the water-soluble Rh/NaTPPTS catalyst dissolved in a green polar phase consisting only of the safe and benign solvents water and 2-propanol. This approach allows to completely avoid the use of additional auxiliaries like surfactants, cyclodextrins, or other phase-transfer agents. Along with efficient immobilization and recycling of the catalyst, excellent chemo- (>96%) and regioselectivity (>98%) to the desired branched aldehyde products is achieved. Investigations on the composition- and temperature-dependent phase-behaviour of the multicomponent liquid system water/2-propanol/methyl oleate are carried out in order to optimise all reaction parameters. Beneficially, a pure nonpolar aldehyde product phase is obtained after reaction, containing only low amounts of 2-propanol (

Via an all‐catalytic route, long‐chain diamines were prepared by the catalytic direct amination of long‐chain diols, derived from plant oils. High conversion was achieved with good selectivity, with the amount of nitrile impurities formed suppressed to a low level. From the lignocellulose‐based 5‐hydroxymethylfurfural (5‐HMF), or from bis(hydroxymethyl)furan, 2,5‐bis(aminomethyl)furan (BAMF) was generated. 5‐HMF was converted in a one‐pot, one‐step direct amination and reductive amination using ammonia. In both cases, the reaction proceeded very efficiently. In the combined amination and reductive amination, the H2 concentration is a rate‐limiting factor. Reducing the partial pressure of H2 also shortened the reaction time required significantly. Polycondensation of the long‐chain diamines with long‐chain diacids led to higher molecular weight polyamides, illustrating the quality of the diamines obtained by this synthetic approach as monomers. published

We herein report the synthesis, application and recycling of stable, polyhedral oligomeric silsesquioxane (POSS)-modified ruthenium complexes. The efficiency of all catalysts was evaluated in the ring closing metathesis of a test system relative to the commercially available Grubbs–Hoveyda second generation catalyst. Recycling experiments were carried out with a ceramic membrane in a cat-in-a-cup setup, where the necessity of two POSS units, one on the N-heterocyclic carbene, as well as one on the benzylidene moiety, was shown. ICP analyses were carried out to prove the low levels of ruthenium contamination in the product solutions and thus the high retention of catalyst by the membrane.

The catalytic activity of a series of Ru-PNP pincer ligand complexes was studied in the direct amination of alcohols with ammonia. It turned out that all complexes of PNP ligands bearing a secondary amine showed no activity in this hydrogen-shuttling reaction sequence, while all complexes of homologous ligands bearing a tertiary amine gave active catalysts. Further comparative studies on catalysts bearing an acridine-based PNP pincer ligand and a PNP ligand of the Xantphos family provided valuable mechanistic insight that led to the design of a highly active catalyst. It appears that in the group of ligands studied here only ligands that do not form stable Ru-amido complexes are active alcohol amination catalysts.

Aldoxime synthesis directly starting from alkenes was successfully achieved through the combination of hydroformylation and subsequent condensation of the aldehyde intermediate with aqueous hydroxylamine in a one-pot process. The metal complex Rh(acac)(CO)(2) and the water-soluble ligand sulfoxantphos were used as the catalyst system, providing high regioselectivities in the initial hydroformylation. A mixture of water and 1-butanol was used as an environmentally benign solvent system, ensuring sufficient contact of the aqueous catalyst phase and the organic substrate phase. The reaction conditions were systematically optimised by Design of Experiments (DoE) using 1-octene as a model substrate. A yield of 85% of the desired linear, terminal aldoxime ((E/Z)-nonanal oxime) at 95% regioselectivity was achieved. Other terminal alkenes were also converted successfully under the optimised conditions to the corresponding linear aldoximes, including renewable substrates. Differences of the reaction rate have been investigated by recording the gas consumption, whereby turnover frequencies (TOFs) >2000 h(-1) were observed for 4-vinylcyclohexene and styrene, respectively. The high potential of aldoximes as platform intermediates was shown by their subsequent transformation into the corresponding linear nitriles using aldoxime dehydratases as biocatalysts. The overall reaction sequence thus allows for a straightforward synthesis of linear nitriles from alkenes with water being the only by-product, which formally represents an anti-Markovnikov hydrocyanation of readily available 1-alkenes.

While homogeneous catalysts can be used to efficiently produce intermediate and specialty chemicals, the separation of the precious catalyst from products, by-products or co-products can be a major challenge. Consequently, novel processes need to be developed to effectively separate and reuse the active catalyst, while avoiding accumulation of the various reaction products. Therefore, this work presents the development and demonstration of a hybrid, continuous reaction and separation process for the catalytic auto-tandem hydroaminomethylation (HAM) reaction. Herein, long-chain alkenes are converted to valuable higher aliphatic amines with high atom economy, while producing only water as co-product. Since the HAM is a rhodium-catalyzed reaction, a thermomorphic multiphase system is used as an integrated catalyst recycling strategy, which is further combined with a membrane-based separation of the co-product via organic solvent nanofiltration. Based on initial screening of various membranes and investigation on the water influence on the phase separation after the reactor, the full process for the HAM of 1-decene with diethylamine with separation of the co-product water was operated continuously for 75 h in a miniplant. The continuous operation of the process successfully demonstrated stable process operation, avoiding a steady accumulation of water while maintaining high catalyst rejection between 97% and 99.3%. The overall leaching of rhodium was kept below 3% of the total amount supplied. This corresponds to a loss of only 11 mg of catalyst per kg of product.

Innovative reactor concepts show evidence to significantly improve the reaction performance in comparison to conventional reactor systems. To evaluate the reactor concepts, experimental investigati...

Micelle-like polymer particles have been applied in aqueous multiphasic hydroformylation reactions of long chain alkenes. These colloids act as phase transfer agents for the nonpolar substrates and as carriers for the catalyst bearing sulfonated ligands by electrostatic attraction. The catalyst performance and the phase separation were optimized with special focus on the conversion, selectivity and catalyst recovery, as those are key points in multiphasic systems to achieve a feasible industrial process. The effect on the catalyst performance of the number of sulfonate groups and electron withdrawing trifluoromethyl groups in the ligand has been studied. The approach was successfully demonstrated for 1-alkenes from 1-hexene to 1-dodecene. For 1-octene, a TOF of more than 3000 h−1 could be achieved at a substrate to catalyst ratio of 80 000, while keeping the rhodium and phosphorous leaching below 1 ppm. In repetitive batch experiments the catalyst was recycled four times, yielding an accumulated TON of more than 100 000 for 1-octene.

The asymmetric hydrocyanation of vinylarenes was investigated using hydrogen cyanide (HCN) in the presence of 5 mol% of a catalyst prepared from a phenol-derived chiral phosphine-phosphite ligand and bis(cyclooctadiene)nickel [Ni(cod)2]. The reactions were performed in tetrahydrofuran (THF) at room temperature to give exclusively the branched nitriles with superior enantioselectivities of 88–99% ee for vinylarenes and 74–94% ee for vinylheteroarenes, respectively. Using styrene as a model substrate it was shown that the catalyst loading could be decreased to 0.42 mol% without any loss of selectivity (88% ee). The structure of the pre-catalyst, i.e., a tetrahedral Ni(0)(P,P-chelate)(cod) complex, was proven by X-ray and NMR analysis. Additional insight into the reaction course was gained by monitoring the hydrocyanation of styrene-d8 by means of 2D NMR spectroscopy.

A supported Pt nanoparticle-based catalyst was used in the chemoselective hydrogenation of nitroarenes to N-arylhydroxylamines (N-AHA). Optimization of NB hydrogenation conditions showed that substantially higher N-PHA yields can be obtained at low temperature. Especially, the influence of an increased hydrogen pressure on selectivity is remarkable. Maximum yields increase from 55% N-PHA at 4 bar H2 to 80% at 23 bar H2 in ethanol. Further optimization led to the use of small amounts of amine additive, TMEDA, with 50 bar H2 raising the maximum yield to 97% N-PHA. The decreased N-PHA hydrogenation rate at high H2 pressure and the presence of TMEDA allow for selective transformation of a range of other nitroarenes containing electron-withdrawing and -donating (reducible) functional groups to their N-AHAs in excellent (more than 90%) yields.

Hypothesis Colloidal particles have been used to covalently bind ligands for the heterogenization of homogeneous catalysts. The replacement of the covalent bonds by electrostatic interactions between particles and the catalyst could preserve the selectivity of a truly homogeneous catalytic process. Experiments Functionalized polymer particles with trimethylammonium moieties, dispersed in water, with a hydrophobic core and a hydrophilic shell have been synthesized by emulsion polymerization and have been thoroughly characterized. The ability of the particles with different monomer compositions to act as catalyst carriers has been studied. Finally, the colloidal dispersions have been applied as phase transfer agents in the multiphasic rhodium-catalyzed hydroformylation of 1-octene. Findings The hydrodynamic radius of the particles has been shown to be around 100 nm, and a core-shell structure could be observed by atomic force microscopy. The polymer particles were proven to act as carriers for the water-soluble hydroformylation catalyst, due to electrostatic interaction between the functionalized particles bearing ammonium groups and the sulfonated ligands of the catalyst. The particles were stable under the hydroformylation conditions and the aqueous catalyst phase could be recycled three times.

As catalysis spans a wide range and involves many disciplines, this chapter does not aim to line out all current challenges. Many of those challenges are related to environmental issues and the urgent need for more sustainable production methods, next to important persisting fundamental questions. We want to create the mindset that is needed to tackle those challenges and give examples of recent developments. A common feature is the integration of knowledge and disciplines that goes along with vanishing disciplinary boundaries that, anyway, only exist in our heads.

The performance of homogeneous catalysts is largely controlled by the ligands bound to the central metal. This chapter presents the most common concepts in Homogeneous Catalysis to rationalize and predict typical ligand influences. Those concepts and their particular predictive power are demonstrated based on selected examples.

Although homogeneous catalysis provides advantages, such as high activity, selectivity and tunability of a catalyst, applications in industry will always require efficient solutions for the intrinsic separation problem. The major drawback results from the difficult recovery and recycling of these expensive and mostly toxic transition metal complexes. Multiple approaches tackle this issue by immobilising homogeneous catalysts. Typically, catalysts can be anchored to suitable supports or immobilised using multiphasic techniques. More elaborate approaches combine size-exclusion filtration with continuous flow catalysis, enabling simultaneous catalyst and product separation through nanofiltration membranes. This chapter will give an overview of these methods and critically discuss their advantages, drawbacks and distinguish between established and more recent achievements.

In two case studies, the reaction performance of the aqueous biphasic hydroformylation of two industrially relevant oleochemicals, namely methyl 10‐undecenoate (case 1) and methyl oleate (case 2), is significantly improved by the use of a Jet‐Loop Reactor concept. Based on previously reported studies, only the two green and benign co‐solvents, 1‐butanol and isopropanol are applied, respectively, in the absence of any additional auxiliary. Both reactions benefit highly from using this special piece of equipment, specifically designed for improving gas–liquid–liquid mixing to create large interfacial areas with no moving internals. In case 1, the loading of the co‐solvent 1‐butanol is successfully reduced. For the first time significant yields (>40% after 1 h) are obtained in the absence of any co‐solvent, which is very beneficial, since aldehyde products and substrate form a pure product phase enabling straightforward separation. In case 2, the loading of the substrate methyl oleate is successfully increased from 6 to 30 wt% still showing satisfying productivity. At 15 wt%, the yield of the desired internal aldehydes in the jet‐loop reactor is increased by a factor of five compared to a stirred tank reactor after 3 h. Practical Applications: The production of aldehydes from hydroformylation of olefins is highly relevant for the chemical industry, since these can undergo numerous subsequent reactions, to form for instance alcohols, amines, and carboxylic acids. Generally, aldehydes from oleochemicals can serve as platform chemicals for gaining access to bifunctional molecules, which are interesting as polymer precursors. Performing hydroformylation with a water‐based solvent system enables efficient product separation from the aqueous catalyst phase for the realzation of more sustainable processes. By using the Jet‐Loop Reactor, the performance of the reaction system can be greatly improved addressing its practical relevance.

The overall productivity of the aqueous biphasic hydroformylation of the castor oil‐derived methyl 10‐undecenoate is increased. To increase the reaction rate, the miscibility of water and the fatty compound is increased by addition of the green solvent 1‐butanol as co‐solvent. For the first time, the concentration of solvents, substrate, and product within the reaction process is experimentally examined in a biphasic system under 20 bar pressure of synthesis gas and 140 °C. A reactor to get samples of both phases is developed to determine the quarternary mixture of the reaction system presented in a four‐dimensional tetrahedron diagram. With the knowledge gained about the reaction and its drivers, it is possible to increase the efficiency of the reaction process reported so far. With simultaneously high reaction rates (turn over frequency = >5000 h⁻¹), the space–time yield of the reaction reaches values of >120 g L⁻¹h⁻¹ and can be improved significantly without negatively affecting catalyst leaching. Practical Applications: Most polymers are made of petrochemicals. Here, the development of a highly efficient process for the formation of bifunctional molecules starting from technical grade methyl 10‐undecenoate made from castor oil in an aqueous biphasic reaction system is presented. By rhodium catalyzed hydroformylation, an aldehyde ester is formed which can be used to create alcohols, carboxylic acids, and amines. Subsequently, these molecules can be used as polymer precursors in polycondensation reactions.

The kinetics of Rh-catalyzed neohexene hydroformylation were investigated with the bulky monodentate ligand tris(2,4-di-tert-butylphenyl)phosphite. The hydrogenolysis of the Rh–acyl intermediate was identified as the rate-limiting step for both the linear and the branched aldehydes. Rate equations for both aldehydes were derived and kinetic parameters were estimated. Increased aldehyde linearity at higher temperatures, frequently observed in hydroformylation, was elucidated by deuterioformylation experiments. These showed that at 100 °C the formation of linear Rh–alkyl was more reversible than the formation of the branched derivative. The ratio of linear to branched Rh–acyl species was determined by in situ high-pressure IR spectroscopy experiments, which allowed the difference in the activation energies for the hydrogenolysis steps towards the aldehyde isomers to be quantified. The hydrogenolysis of Rh–acyl was found to be the step that caused the greatest temperature effect on the regioselectivity.

Effective and modular synthetic approaches toward phosphine-phosphite ligands and phosphine-phosphonite ligands featuring a diphenyl ether backbone have been developed. The phosphine-phosphite ligands are obtained by a two-step protocol from 2-bromo-2-methoxydiphenyl ether. The phosphine-phosphonite ligands are prepared in a four-step synthetic protocol that involves a novel, unsymmetrical diphenyl ether derived phosphine-phosphorusdiamide as key building block. Structural studies on Pt-II complexes with either phosphine-phosphite or phosphine-phosphonite ligands indicate strict cis coordination for these ligand systems. High-pressure NMR spectroscopy studies of Rh complexes under syngas indicate the presence of two ea isomers for Rh(H)(CO)(2)(PP). The existence of this mixture is further supported by high-pressure IR spectroscopy studies. In order to benchmark the activity and selectivity of these novel, wide-bite-angle, mixed-donor ligands, they were screened in Pd-catalyzed asymmetric allylic alkylation as well as Rh-catalyzed hydrogenation and hydroformylation reactions. The ligands give 100% conversion and low-to-moderate enantioselectivity in the allylic alkylation of 1,3-diphenyl-2-propenyl acetate and cyclohexyl-2-enyl acetate with dimethyl malonate. In the hydroformylation of styrene, good conversion and regioselectivities are achieved but only moderate enantioselectivity. The ligands give good conversions in asymmetric hydrogenation of typical substrates, with good-to-excellent enantioselectivities of up to 97% depending on the substrate.

The kinetics of Rh-catalysed cyclooctene hydroformylation were investigated, based on the mechanism described for a single tris(2,4-di-tert-butylphenyl)phosphite ligand coordinated to a rhodium center. The rate limiting step was found to be the coordination of cyclooctene to the metal center as suggested in literature. Parameters of the corresponding rate equation were estimated by nonlinear regression. Experimental data obtained from semi-batch reactions were compared with model predictions and shown to be in good agreement. A continuous jet-loop reactor with coupled nanofiltration was designed and the kinetics were validated.

A slightly adapted catalyst system has been successfully applied in the direct amination of primary and secondary alcohols. Moreover, the applicability to diols has been shown, giving high selectivity towards the primary diamines. It was found that the Ru/P ratio as well as the amount of ammonia used are highly important in this system, especially for higher substrate loadings. The catalyst was employed on a larger batch scale for the conversion of isomannide to the corresponding diamine. Additionally, it was shown that the catalyst is stable for at least six consecutive runs. No significant loss of activity and selectivity was observed.

A variety of 5-, 6- and 8-(4-aminobutyloxy)quinolines as novel oxygen analogues of known 4- and 8-(4-aminobutylamino)quinoline antimalarial drugs was generated from hydroxyquinolines through a three-step approach with a rhodium-catalyzed hydroformylation as the key step. Antiplasmodial assays of these new quinolines revealed micromolar potency for all representatives against a chloroquine-sensitive strain of Plasmodium falciparum, and three compounds showed submicromolar activity against a chloroquine-resistant strain of P. falciparum with IC(50)-values ranging between 150 and 680 nM.

Hydroformylation of terminal alkenes in alcohol solvents leads to the selective formation of the corresponding acetals. The Xantphos ligand gave the best results as well as acetal selectivities higher than 99% and linear/branched ratios of up to 52 were obtained. The scope of the reaction was studied. Acetals were found to be unreactive under hydroaminomethylation conditions.

An innovative BASF catalyst manufacturing technology (NanoSelect (TM)) is introduced which allows production of heterogeneous catalysts with excellent control over metal crystallite sizes. NanoSelect (TM) technology enabled the development of Pd catalysts which are lead-free Lindlar catalyst replacements in alkyne-to-cis-alkene hydrogenations. NanoSelect (TM) Pt catalysts showed excellent chemoselectivity in substituted nitro-arene hydrogenation reactions without build-up of hydroxylamine intermediates. All NanoSelect (TM) produced catalysts show markedly higher activity per gram of metal leading to ten-fold less use of precious metal

Optimisation of the reaction conditions for the rhodium-catalysed aldehyde hydrogenation under hydroformylation conditions showed that water used as co-solvent enhances both rate and selectivity towards primary alcohols. One-pot hydroformylation–hydrogenation using rhodium as the only transition metal yielded alcohols in excellent selectivities and good linearities.