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Herein, we report an efficient metal-free system for the transfer hydrogenation of esters and carbonates with ammonia borane as hydrogen donor, by-passing the otherwise ubiquitous formation of transesterification side-products.

In this article, we describe the benefits of sublimation for natural product and food chemistry. The direct sublimation of substances from dried plant powders has not received much attention in research in the past, just like the sublimation of substances from dried plant extracts. We used sublimation to study dried sea buckthorn berry powders and dried sea buckthorn berry extracts. The results of the powder sublimations were compared to that of dried chokeberry, wolfberry, and European cornel powder. 52 marker substances of which 27 are specific for sea buckthorn were found in the sea buckthorn powder sublimates using LC/MS. The majority of them are not described in the literature and were obtained by direct sublimation. Accordingly, sublimation can help to identify new plant constituents. Our identification method was validated by the analysis of four commercially available fruit powders. The sea buckthorn powder showed an almost 80% correlation with the determined marker substances, whereas the other fruit powders did not achieve more than 38% correlation. The sublimates of sea buckthorn extracts show additional marker substances compared to the fruit powder sublimate, and we think that both techniques can be used to fight food fraud.

Herein, we report an efficient metal-free system for the transfer hydrogenation of esters and carbonates by-passing the otherwise ubiquitous formation of transesterification side-products. The Lewis acid B(C

Hydrogels have become an increasingly interesting topic in numerous fields of application. In addition to their use as immobilization matrixes in (bio)catalysis, they are widely used in the medical sector, e.g., in drug delivery systems, contact lenses, biosensors, electrodes, and tissue engineering. Cartilage tissue engineering hydrogels from natural origins, such as collagen, hyaluronic acid, and gelatin, are widely known for their good biocompatibility. However, they often lack stability, reproducibility, and mechanical strength. Synthetic hydrogels, on the other hand, can have the advantage of tunable swelling and mechanical properties, as well as good reproducibility and lower costs. In this study, we investigated the swelling and mechanical properties of synthetic polyelectrolyte hydrogels. The resulting characteristics such as swelling degree, stiffness, stress, as well as stress-relaxation and cyclic loading behavior, were compared to a commercially available biomaterial, the ChondroFiller® liquid, which is already used to treat articular cartilage lesions. Worth mentioning are the observed good reproducibility and high mechanical strength of the synthetic hydrogels. We managed to synthesize hydrogels with a wide range of compressive moduli from 2.5 ± 0.1 to 1708.7 ± 67.7 kPa, which addresses the span of human articular cartilage.

Regenerated cellulose is a natural, renewable and biodegradable material but is commonly obtained via environmentally hazardous processes. Here, a simple, environmentally friendly route is presented involving rapid coagulation of dissolved cellulose by nontoxic organic carbonates.

Furanic di-carboxylate derivatives of 5-Hydroxymethylfurfural (HMF) are nowadays important in the polymer industry as they are used as building blocks for bio-based polyesters. The high reactivity of HMF compels to avoid harsh synthetic conditions. Therefore, developing mild catalytic processes for its selective oxidation is a challenging task. Herein, we report the first oxidative esterification of HMF to dimethyl furan-2,5-dicarboxylate (FDCM) under flow conditions using oxygen as oxidant. For that purpose, a new series of nitrogen-doped carbon-supported bimetallic Co/Ru heterogeneous catalysts were prepared and characterized by XRD, XPS and N2 physisorption. These analyses revealed that the porosity of the materials and order of impregnation of the metals to the carbon supports lead to varying catalytic activities. Under optimized conditions the flow reactor showed a 15-fold increase on the production of FDCM compared to batch conditions. �� 2020 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

Die Katalyse ist ein sehr komplexes und interdisziplinäres wissenschaftliches Gebiet, das die effiziente Herstellung einer Vielzahl von Produkten für verschiedene Branchen und in unterschiedlichen Produktionsgrößen ermöglicht. Somit ist die Katalyse eine der Schlüsseltechnologien zur Bewältigung wesentlicher Herausforderungen wie einer nachhaltigen Energieversorgung oder des Klimawandels. Das Datenmanagement in der Katalyse ist derzeit überwiegend auf institutioneller oder Arbeitsgruppenebene organisiert und basiert auf lokalen Konventionen. Übergreifende Repositorien und Standards, wie Daten inklusive Metadaten gespeichert werden sollen, existieren nur in rudimentärer Form. Um den höchstmöglichen Mehrwert aus der Katalyseforschung zu generieren, ist ein grundlegender Wandel in der Katalyseforschung und den katalyseverwandten Wissenschaften wie Chemieingenieurwesen und Verfahrenstechnik erforderlich. Die verschiedenen Disziplinen der Katalyse im Hinblick auf das Datenmanagement zusammenzuführen, ist die zentrale Herausforderung. Aus all diesen Notwendigkeiten heraus wurde im Rahmen der Initiative zur Nationalen Forschungsdateninfrastruktur (NFDI) das NFDI4Cat-Konsortium gegründet. Als eines von derzeit neun geförderten Konsortien konzentriert sich NFDI4Cat auf die Wissenschaften rund um die Katalyse. Dieser Artikel beschreibt die Motivation der Gründungsmitglieder für dieses im Oktober 2020 gestartete Konsortium und wie die Ziele in Bezug auf die Fachcommunity, die technische Infrastruktur und insbesondere das Forschungsdatenmanagement erreicht werden sollen. Darüber hinaus eröffnet die dynamische Entwicklung moderner Technologien zur Erfassung, Bereitstellung und zur Analyse großer Datenmengen neue Möglichkeiten für wissenschaftlichen Fortschritt in den Einzeldisziplinen und insbesondere an deren Nahtstellen.

An electrolyte solution of tetrabutylphosphonium hydroxide (TBPH) in water can dissolve over 20 wt % of cellulose in minutes and therefore constitutes a promising alternative green solvent system compared to known imidazolium- or dimethylacetamide-based systems. Overcoming the disadvantage of the extremely high viscosity of TBPH/cellulose solutions can facilitate their use for various applications. In this study, the application of cosolvents for the reduction, and thus adjustability, of the viscosity is addressed. Even well-known antisolvents can be easily deployed, resulting in a dramatic drop in viscosity. High concentrations of cosolvents (excluding ethanol) are tolerated without precipitation of the dissolved cellulose. Furthermore, the effect of the cosolvents on the additional dissolution of cellulose is discussed. The amount of dissolved cellulose is quantified by 13 C NMR spectroscopy.

Hydrogels are one of the emerging classes of materials in current research. Besides their numerous applications in the medical sector as a drug delivery system or in tissue replacement, they are also suitable as irrigation components or as immobilization matrices in catalysis. For optimal application of these compounds, knowledge of the swelling properties and the diffusion mechanisms occurring in the gels is mandatory. This study is focused on hydrogels synthesized by radical polymerization of imidazolium-based ionic liquids. Both the swelling and diffusion behavior of these hydrogels were investigated via gravimetric swelling as well as sorption experiments implemented in water, ethanol, n-heptane, and tetrahydrofuran. In water and ethanol, strong swelling was observed while the transport mechanism deviated from Fickian-type behavior. By varying the counterion and the chain length of the cation, their influences on the processes were observed. The calculation of the diffusion coefficients delivered values in the range of 10−10 to 10−12 m2 s−1. The gravimetric results were supported by apparent diffusion coefficients measured through diffusion-weighted magnetic resonance imaging. A visualization of the water diffusion front within the hydrogel should help to further elucidate the diffusion processes in the imidazolium-based hydrogels.

Ionic liquids are highly charged compounds with increasing applications in material science. A universal approach to synthesize free-standing, vinylalkylimidazolium bromide-containing membranes with an adjustable thickness is presented. By the variation of alkyl side chains, membrane characteristics such as flux and mechanical properties can be adjusted. The simultaneous use of different ionic liquids (ILs) in the synthesis can also improve the membrane properties. In separation application, these charged materials allowed us to retain charged sugars, such as calcium gluconate, by up to 95%, while similar neutral compounds such as glucose passed the membrane. An analysis of the surface conditions using atomic force microscopy (AFM) confirmed the experimental data and explains the decreasing permeance and increased retention of the charged sugars.

This short review highlights the role of reaction engineering as a tool for bioprocess development. Selected examples are discussed that demonstrate the need to understand thermodynamic and kinetic properties of the reaction system in order to identify potential bottlenecks. For coupled enzyme systems and reaction cascades modelling as well as selection of suitable reactor configurations is discussed. For the problem of overcoming product inhibition examples are given, followed by selected examples for in situ product removal. Finally, two reactor concepts for oxidation reactions requiring oxygen are briefly presented.

In this work ion functionalized hydrogels as potent drug delivery systems are presented. The ion functionalization of the hydrogel enables the retention of ionic drug molecules and thus a reduction of burst release effects. Timolol maleate in combination with polymerized anionic 3-sulfopropylmethacrylate potassium and ibuprofen combined with cationic poly-[2-(methacryloyloxy)ethyl] trimethylammonium chloride are investigated in respect to their drug release profile. The results are showing an ion exchange depending release behavior instead of a diffusion-controlled drug release as it is known from common drug delivery systems. Furthermore, the suitability of such hydrogels for standard methods for sterilization is investigated.

The large pool of naturally occurring carbohydrates with their diversity in chirality and structure led to the idea of a systematic investigation of carbohydrate based ILs. To this end, we investigated the influence of different ether groups, mainly methyl or ethyl ether, on the secondary OH groups as well as different configurations on physical properties such as melting point, thermostability and especially the influence on cell toxicity. For this investigation we chose α- and β-methyl-, β-allyl- and β-phenyl d-glucopyranose as well as four 1-deoxy-pentoses. In order to be able to classify the results, more ionic liquids with different structural motives were examined for cytotoxicity. Here, we present data that confirm the biocompatibility of such ILs consisting of naturally occurring molecules or their derivatives. The synthesized carbohydrate based ILs were tested for their suitability as additives in coatings for medical applications such as drug-eluting balloons.

New derivatives of serinol, 3-[4-(2-chloroethoxy)benzyloxy]-2-phthalimidopropan-1-ol and 3-[4-(2-azidoethoxy)phenoxy]-2-phthalimidopropan-1-ol, were synthesized and tested as glycosyl acceptors in stereoselective 1,2-cis-galactosylation in the benzyl-free synthesis of analogs of α-linked galactosylceramides. It was found that NIS/AgOTf-promoted glycosylation of 3-[4-(2-chloroethoxy)benzyloxy]-2-phthalimidopropan-1-ol with ethyl 4,6-O-(di-tert-butylsilylene)-1-thio-β-D-galactoside resulted in both the expected α-linked diastereomeric glycosides and the product of iodination of the benzyl group of the aglycon. This process was avoided by using the corresponding galactosyl imidate under Et3SiOTf promotion to give exclusively α-linked diastereometic serinol glycosides.

Ionic liquids are well known and frequently used 'designer solvents' for biocatalytic reactions. This review highlights recent achievements in the field of multiphasic ionic liquid-based reaction concepts. It covers classical biphasic systems including supported ionic liquid phases, thermo-regulated multi-component solvent systems (TMS) and polymerized ionic liquids. These powerful concepts combine unique reaction conditions with a high potential for future applications on a laboratory and industrial scale. The presence of a multiphasic system simplifies downstream processing due to the distribution of the catalyst and reactants in different phases.

Enzyme immobilization in polymerized ionic liquids (PILs) promises to be a versatile tool for simple recovery and reuse of catalysts. In this study, a raw extract of CalB was encapsulated in poly(VEImBr) and assessed with respect to solvent, temperature, amount of enzyme, leaching behavior, and reusability on the example of the kinetic resolution of rac-1-phenylethanol with vinyl acetate. This immobilization method increased the enzyme activity of the CalB raw extract in comparison to the non-immobilized enzyme. The desired product was synthesized with high enantiomeric excess (ee) and no leaching of active enzyme was observed in the experiments. The immobilization method was compared to Novozyme 435 and Lipozyme RM IM, as commercially available immobilisates. Nonpolar solvents, including n-heptane and n-dodecane, proved to be the best reaction solvents, showing nearly full conversion and high catalytic activities. The encapsulated ­lipase was easily recovered from the reaction mixture and reused for ten cycles.

Aqueous two-phase systems (ATPS) occur by the mixture of two polymers or a polymer and an inorganic salt in water. It was shown that not only polymers but also ionic liquids in combination with inorganic cosmotrophic salts are able to build ATPS. Suitable for the formation of ionic liquid-based ATPS systems are hydrophilic water miscible ionic liquids. To understand the driving force for amino acid and peptide distribution in IL-ATPS at different pH values, the ionic liquid Ammoeng 110™ and K2HPO4 have been chosen as a test system. To quantify the concentration of amino acids and peptides in the different phases, liquid chromatography and mass spectrometry (LC–MS) technologies were used. Therefore the peptides and amino acids have been processed with EZ:faast™-Kit from Phenomenex for an easy and reliable quantification method even in complex sample matrices. Partitioning is a surface-dependent phenomenon, investigations were focused on surface-related amino acid respectively peptide properties such as charge and hydrophobicity. Only a very low dependence between the amino acids or peptides hydrophobicity and the partition coefficient was found. Nevertheless, the presented results show that electrostatic respectively ionic interactions between the ionic liquid and the amino acids or peptides have a strong impact on their partitioning behavior.

Herein we report the synthesis of isotactically enriched poly(cyclohexene carbonate) (PCHC) by the bulk alternating copolymerization of meso-cyclohexene oxide and carbon dioxide using dialkylmagnesium compounds as catalyst. These simple achiral catalysts showed good activity for the isoselective copolymerization, with high yield and high carbonate-linkage contents, in a controlled manner under mild conditions and atmospheric CO2 pressure. The triad sequences in the 13C NMR spectra of these polymers were assigned using Bernoullian statistical methods in order to determine the tacticity of the copolymer. Differential scanning calorimetry analysis confirmed the formation of highly isotactic polycarbonate. Furthermore, kinetic studies and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry investigations allowed us to shed light on the reaction mechanism of the polymerization process.

In the past decades, ionic liquids (IL) evolved from a “designer solvent” to a well-known and well-characterized class of compounds useful in reactions, extractions, and other applications. By an increasing number of synthesized ILs also new fields of application were uncovered. The todayʼs research interest covers a range for direct use of ILs, application as embedding material or as catalyst. In this brief review, we present diverse applications of pure native ILs as well as these of polymerized ionic liquids (PILs). These charged polymers unite the presented advantages of both, ionic liquids and solid polymer structures. We also show the recent developments in the areas of drug delivery, catalysis and catalyst immobilization where these particular compositions demonstrate improvements compared to existing solutions. Besides the advantages, we likewise discuss some limitations and drawbacks.

For the development of intelligent implant systems hydrogels (HG) from crosslinked ionic liquids feature a high potential to be utilised as a drug depot. Biocompatibility of the HGs is one key prerequisite for biomedical applications. HGs were polymerised from a variety of different ionic monomers based on methacrylate, methacrylamide, styrene or vinyl imidazolium derivatives in aqueous solution. N,N'-methylenebisacrylamide was used as crosslinker. CellQuanti-Blue™ Cell Viability Assay Kit was implemented to proof viability of L929 mouse fibroblasts. The predominant part of the HG eluates generated only a marginal reduction of less than 15% cell viability at 100% eluate concentration. This underlines the excellent suitability of these HGs for biomedical applications and revealed some promising candidates for the development of drug depots for implants.

BACKGROUND Spray congealing is investigated as new innovative immobilization technique for biocatalysts. The immobilization is realized by atomization of a mixture of a melted carrier and the enzyme, which is re-solidifyed due to temperature decrease. This method needs neither organic solvents, nor a difficult downstream processing after preparation. For the encapsulation different matrices, like long chain alcohols and glyceryl derivatives, with melting points below 86 °C and environmentally friendly properties, are chosen and tested for their suitability for enzyme encapsulation. RESULTS The immobilization of a laccase (EC 1.10.3.2, Novozym 51003, from Myceliophthora thermophila) was investigated and the produced microparticles were characterized. The obtained particles showed a mean particle size around 40 µm and a spherical surface with different structures depending on the used matrix. Spray congealing with the laccase reached yields of 80% and residual activities up to 56%. Furthermore, 4 consecutive reactions could be realized with cetyl alcohol as carrier and an activity of 20% could be retained. CONCLUSION Cetyl alcohol was found to be the most appropriate carrier for the immobilization of the investigated laccase, due to an easy handling and high yields. In addition, the best retained activities were obtained compared to other tested carriers and a recycling of the biocatalyst could be realized.

This Focus Review describes state-of-the-art methods for the preparation of antimicrobial silicones. Given the diversity of antimicrobial activity and their mechanisms, the performance of these materials is highly dependent on the characteristics of the polymeric matrix. Therefore, different synthetic routes have been developed, such as 1) physical treatments, 2) chemical transformations, and 3) copolymerization. This classification is not exclusive, so some products belong to more than one class. Herein, we attempt to present a handy overview of the development of antimicrobial silicones, their most important application fields, the most relevant antimicrobial assays, and, as the title suggests, an overview of the most relevant preparation methods.

CO2 -induced switchable tertiary amine-based organocatalysts were investigated for an efficient catalyst and product separation by its different partitioning between an organic and carbonated water phase. In this case study, the switching ability of eight tertiary amine-based catalysts between the organic and water phase by addition or removal of CO2 was investigated. Here, the catalyst switched both nearly completely (99.9 %) into the aqueous phase by addition of CO2 and effectively back into the organic phase (99.3 %) by expelling CO2 . With this technique, the organocatalyst was successfully recovered and reused twelve times without significant loss of activity (up to 90 % enantiomeric excess) for the asymmetric nitroaldol (Henry) reaction. After the first catalyst switch, evaporation of the solvent affords the product in 98 % purity without any further purification steps.

Several bifunctional phosphonium salt catalysts were prepared and immobilized on silica and polystyrene supports. The immobilized systems were compared with their homogeneous analogs in cyclic carbonate synthesis. Interestingly, in some cases, higher activities were observed for the immobilized catalysts. The most active system was a phenol-functionalized phosphonium salt supported on a silica surface. The covalent linkage of the phosphonium unit to the silica was verified by solid-state NMR and FT-IR. SEM and EDX measurements revealed a homogeneous distribution of the phosphonium salt on the particle surface. This catalyst facilitated the addition of CO2 to epoxides under mild conditions. The evaluation of the substrate scope and the catalyst recycling were combined in one set of experiments. In 15 consecutive runs, the synthesis of 12 cyclic carbonates in yields of up to 98% was achieved. The investigation of the catalyst after the recycling experiments revealed the loss of the original anion (bromide) as well as a decrease in the number of phosphonium units, which explained the observed deactivation of the catalyst during the recycling experiments.

A fundamental electrochemical study of several highly diluted ionic liquids (ILs) at the interface between two immiscible electrolyte solutions (ITIES) is reported to evaluate the electrochemical and the solvation properties of [BMIM]Cl, [BMIM]BF4, [BMIM]OTf, [EMIM]Br and [AMIM]Cl. The interface is formed between a hydrophilic electrolyte dissolved in water and a hydrophobic electrolyte dissolved in an organic solvent, here 1,2-dichloroethane (DCE). The transfer of the highly diluted ionic species from the water phase into the organic phase occurs when an electrical potential difference is applied across the interface. Standard Gibbs energy of transfer, the relative hydrophilicity/hydrophobicity and transfer coefficients across the interface of the selected ILs are determined by cyclic voltammetry at large ITIES.

The applicability of ionic liquid-water-based thermomorphic solvent (TMS)-systems with an upper critical solution temperature for homogeneous biocatalysis is investigated. Cholinium- and imidazolium-based ionic liquids are used to facilitate a temperature-dependent phase change, which can be easily fine-tuned by adding salts or polar organic solvents. Within the TMS-system, a high enzymatic activity and subsequent full conversion is achieved in the intermittent monophasic reaction system of the TMS-system. Therefore, the biocatalyst can be easily recycled after separating the phases at lower temperatures.

The synthesis of more than 10 new magnetic ionic liquids with [MnX4]2&minus, anions, X = Cl, NCS, NCO, is presented. Detailed structural information through single-crystal X-ray diffraction is given for (DMDIm)[Mn(NCS)4], (BnEt3N)2[Mn(NCS)4], and {(Ph3P)2N}2[Mn(NCO4)]&middot, 0.6H2O, respectively. All compounds consist of discrete anions and cations with tetrahedrally coordinated Mn (II) atoms. They show paramagnetic behavior as expected for spin-only systems. Melting points are found for several systems below 100 &deg, C classifying them as ionic liquids. Thermal properties are investigated using differential scanning calorimetry (DSC) measurements. The physicochemical properties of density, dynamic viscosity, electrolytic conductivity, and surface tension were measured temperature-dependent of selected samples. These properties are discussed in comparison to similar Co containing systems. An increasing amount of bromide impurity is found to affect the surface tension only up to 3.3%.

Hydrogels, based on polymerized ionic liquids, are increasingly used in the medical and pharmaceutical industry as implants, drug delivery systems, contact lens material, bone substitutes and stent coatings. Therefore they need to be biocompatible, flexible and resistant to external stress. In order to meet these requirements, there is a large interest in design, synthesis and characterization of these interesting polymers. In this work, mechanical properties such as gelation kinetics, shear strain resistance, and response to compression and stretching of ten different polymerized ionic liquid-based hydrogels were examined, completing the picture of the rheological behavior of these materials. Interestingly, the investigations of stretching measurements showed a wide range of critical strains leading to failure from 4.8 ± 1.1 to 47.9 ± 15.1%and in compression measurements critical strain from 7.8 ± 3.6 to higher than 59.8 ± 17.3%, as well as a linear viscoelastic range in shear from 14 ± 8 to 267 ± 26%. These results allow improved design with a “choose-the-best-material”-toolbox for medical applications.

A possible application of glycerol, which is produced in large amounts as by-product from the biodiesel industry, is its fermentation to serinol (2-amino-1,3-propanediol), a glycerol derivative. The downstream processing of this glycerol-based fermentation broth was investigated. The challenge of the isolation of serinol was the complex media and the solubility of the desired substance in aqueous media. In this study, the isolation of serinol was investigated by an appropriate reversible derivatization method. Serinol was isolated by protecting the amino group with diethyl ethoxymethylenemalonate directly in the aqueous phase, followed by extraction of the 2,2-bis(ethoxycarbonyl)vinyl-serinol (BECV-serinol) with ethyl acetate resulting in an isolated yield of 63%. We demonstrate the possibility of isolation of a hydroscopic amino alcohol from the fermentation broth and the comparison of the products in water as well as the cleavage of the 2,2-bis(ethoxycarbonyl)vinyl group (BECV group). The procedure can also be used for other amino group containing molecules such as serine, glucosamine, hexylamine and amino methyl laureate. This article is protected by copyright. All rights reserved

We describe a method of observing collisions of single femtoliter (fL) oil (i.e., toluene) droplets that are dispersed in water on an ultramicroelectrode (UME) to probe the ion transfer across the oil/water interface. The oil-in-water emulsion was stabilized by an ionic liquid, in which the oil droplet trapped a highly hydrophobic redox probe, rubrene. The ionic liquid also functions as the supporting electrolyte in toluene. When the potential of the UME was biased such that rubrene oxidation would be possible when a droplet collided with the electrode, no current spikes were observed. This implies that the rubrene radical cation is not hydrophilic enough to transfer into the aqueous phase. We show that current spikes are observed when tetrabutylammonium trifluoromethanesulfonate or tetrahexylammonium hexafluorophosphate are introduced into the toluene phase and when tetrabutylammonium perchlorate is introduced into the water phase, implying that the ion transfer facilitates electron transfer in the droplet collisions. The current (i)-time (t) behavior was evaluated quantitatively, which indicated the ion transfer is fast and reversible. Furthermore, the size of these emulsion droplets can also be calculated from the electrochemical collision. We further investigated the potential dependence on the electrochemical collision response in the presence of tetrabutylammonium trifluoromethanesulfonate in toluene to obtain the formal ion transfer potential of tetrabutylammonium across the toluene/water interface, which was determined to be 0.754 V in the inner potential scale. The results yield new physical insights into the charge balance mechanism in emulsion droplet collisions and indicate that the electrochemical collision technique can be used to probe formal ion transfer potentials between water and solvents with very low (ε5) dielectric constants.

For an alternative synthetic approach toward the heterocyclic industrial chemical e-caprolactone, which is based on a biocatalytic oxidation of readily available cyclohexanol with air in aqueous media (using an alcohol dehydrogenase and a Baeyer–Villiger monooxygenase as enzyme components), a solvent engineering has been carried out identifying isooctane as a suitable co-solvent. Biotransformations in an aqueous-isooctane biphasic solvent system were found to proceed faster at both investigated substrate concentrations of 40 and 80 mm, respectively, compared with the analogous enzymatic reactions in pure aqueous medium. In addition, in all cases quantitative conversions were observed after a reaction time of 23 h when using isolated enzymes. The achievements indicate a high compatibility of isooctane [10%(v/v)] with the enzymes as well as the potential for an in situ removal of the organic reaction components, thus decreasing inhibition and/or destabilization effects of these organic components on the enzymes used. In contrast, so far, the use of recombinant whole-cells gave less satisfactory results, which might be due to limitations of the permeation of, for example, the substrate through the cell membrane.

The electrochemical initiated heterocoupling of 3-methylcatechol and n-hexylamine was investigated. The oxidation of 3-methylcatechol was performed in an electrochemical flow cell with glassy carbon as the working electrode. As a result, the two-electron, two-proton oxidised chinone intermediate undergoes a C-N coupling reaction in the presence of an amine (Michael addition). This mono coupling product can undergo a second two-electron, two-proton oxidation depending on acidic or basic conditions and substrate ratios. This flow cell was coupled on-line with electrospray ionisation mass spectrometry to identify the possible coupling products. Higher substrate concentrations were performed off-line as first scale-up experiments in a two-step procedure.

The very low vapor pressure of ionic liquids is challenging to measure. At elevated temperatures the liquids might start to decompose, and at relatively low temperatures the vapor pressure becomes too low to be measured by conventional methods. In this work we developed a highly sensitive method for mass loss determination at temperatures starting from 350 K. This technique is based on an alternating current calorimeter equipped with a chip sensor that consists of a free-standing SiNx-membrane (thickness1 μm) and a measuring area with lateral dimensions of the order of 1 mm. A small droplet (diameter ca. 600 μm) of an ionic liquid is vaporized isothermally from the chip sensor in a vacuum-chamber. The surface-to-volume-ratio of such a droplet is large and the relative mass loss due to evaporation is therefore easy to monitor by the changing heat capacity (J K(-1)) of the remaining liquid. The vapor pressure is determined from the measured mass loss rates using the Langmuir equation. The method was successfully tested for the determination of the vapor pressure and the vaporization enthalpy of an archetypical ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIm][NTf2]). The data set created in this way in an extremely broad temperature range from 358 K to 780 K has allowed the estimation of the boiling temperature of [EMIm][NTf2]. The value (1120 ± 50) K should be considered as the first reliable boiling point of the archetypical ionic liquid obtained from experimental vapor pressures measured in the most possible close proximity to the normal boiling temperature.

Biologically active compounds from pharmaceuticals cause concern due to their common occurrence in water and sediments of urbanized coasts and potential threat to marine organisms. Atorvastatin (ATO), a globally prescribed drug, is environmentally stable and bioavailable to marine organisms; however, the physiological and toxic effects of this drug on ecologically important coastal species are yet to be elucidated. We studied the effect of ATO (˜1.2 μg L−1) on bioenergetics (including whole-organism and mitochondrial respiration, as well as tissue energy reserves and mRNA expression of genes involved in mitochondrial biogenesis and fatty acid metabolism in the gills and the digestive gland) of a keystone bivalve Mytulis edulis (the blue mussel) from the Baltic Sea. Xenobiotic detoxification systems including activity and mRNA expression of P-glycoprotein, and Phase I and II biotransformation enzymes (cytochrome P450 monooxygenase CYP1A and glutathione transferase, GST) were also assessed in the gill and digestive gland of the mussels. Exposure to ATO caused rapid uptake and biotransformation of the drug by the mussels. Standard metabolic rate of ATO-exposed mussels increased by 56% indicating higher maintenance costs, yet no changes were detected in the respiratory capacity of isolated mitochondria. ATO exposure led to ˜60% decrease in the lysosomal membrane stability of hemocytes and ˜3-fold decrease in the whole-organism P-glycoprotein-driven and diffusional efflux of xenobiotics indicating altered membrane properties. The digestive gland was a major target of ATO toxicity in the mussels. Exposure of mussels to ATO led to depletion of lipid, carbohydrate and protein pools, and suppressed transcription of key enzymes involved in mitochondrial biogenesis (peroxisome proliferator-activated receptor gamma coactivator 1-alpha PGC-1α) and fatty acid metabolism (acetyl-CoA carboxylase and CYP4Y1) in the digestive gland. No bioenergetic disturbances were observed in the gills of ATO-exposed mussels, and elevated GST activity indicated enhanced ATO detoxification in this tissue. These data demonstrate that ATO can act as a metabolic disruptor and chemosensitizer in keystone marine bivalves and warrant further investigations of statins as emerging pollutants of concern in coastal marine ecosystems.

The endoplasmic reticulum (ER) is the site of synthesis and folding of membrane and secretory proteins. The fraction of protein passing through the ER represents a large proportion of the total protein in the cell. Protein folding, glycosylation, sorting and transport are essential tasks of the ER and a compromised ER folding network has been recognized to be a key component in the disease pathogenicity of common neurodegenerative, metabolic and malignant diseases. On the other hand, the ER protein folding machinery also holds significant potential for therapeutic interventions. Many causes can lead to ER stress. A disturbed calcium homeostasis, the generation of reactive oxygen species (ROS) and a persistent overload of misfolded proteins within the ER can drive the course of adisease. In this review the role of ER-stress in diseases of the liver and pancreas will be examined using pancreatitis and Wilson´s disease as examples. Potential therapeutic targets in ER-stress pathways will also be discussed.

Flavonols, a class of flavonoids, are jointly responsible for antioxidant activities as free radical acceptors in flowers, fruits and vegetables. Due to their electroactive behaviour, the oxidation of chrysin, flavonol, kaempferol, morin, quercetin and myricetin in methanol was performed in an electrochemical flow cell with glassy carbon as the working electrode. This flow cell was coupled online with electrospray ionisation mass spectrometry to identify the possible oxidation products. Based on these experiments, it was concluded that when certain structural requirement are present, the initial electrode reaction of flavonols involves an electron delivery electrochemical step followed by a chemical step via methanol addition. The redox activity of the selected species explains the number of observed multiple methoxylation. Moreover, we identified a second two-electron, two-proton oxidation of the formed oxidation products of quercetin and myricetin for the first time.

A novel strategy for the embedding of quinine-based organocatalysts in polymerized ionic liquids-based hydrogels is presented. With this technique, the encapsulated organocatalyst was successfully recovered and reused for four cycles without any loss of enantioselectivity (up to 91% ee) for the asymmetric nitroaldol (Henry) reaction. In this study, high catalyst leaching was significantly reduced (

In this study, the successful use of organic solvent nanofiltration for the purification of three highly enantioselective quinine-based organocatalysts was demonstrated. Commercially available solvent-resistant membranes (DuraMem series) were utilized to remove specific impurities that originated from their respective synthesis pathways. DuraMem 200 exhibited the highest catalyst retention of 99 %, which facilitated catalyst purification at the gram scale with a purity >99 %.

In this work, the development of a chemoenzymatic process for the production of (1S,2R)-1-(methoxycarbonyl)cyclohex-4-ene-2-carboxylic acid by ECS-PLE06 (recombinant pig liver esterase) is presente...

The palladium-catalyzed aminocarbonylation of aliphatic alkenes is presented for the first time without the need for external CO pressure. N,N-dimethylformamide (DMF) is used as an in situ source of both the required carbon monoxide and the amine substrate. The applied palladium catalytic system is well-known for a number of carbonylation reactions, including those with CO surrogates and tandem isomerizing carbonylations. The reaction pathway was investigated and proved to proceed by an acid-catalyzed DMF decomposition to CO and dimethyl amine with subsequent aminocarbonylation of the alkene. Pressure-versus-time curves gave more insight into the correlation between acid concentration and aminocarbonylation activity. Aliphatic alkenes (terminal and internal) are transformed, also in commercial glassware, into the corresponding linear N,N-dimethylamides with excellent selectivities. Hence, amide synthesis by aminocarbonylation moves closer to application in standard organic laboratories.

Organic solvent nanofiltration has been studied as an efficient and mild tool for the separation of phosphorus-based organocatalysts and their subsequent recycling. The atom-economic conversion of butylene oxide with carbon dioxide has been chosen as a test reaction, yielding the desired cyclic carbonate in excellent yields under mild conditions. The utilization of modern solvent-resistant membranes to separate and recycle the organocatalyst from reaction media was established. Commercially available membranes with molecular weight cut-offs between 150 and 500 g·mol–1 were employed. DuraMem 300 proved to be the best membrane, showing excellent rejections of up to 99% for the organocatalyst in the recycling experiments. The catalyst and the membrane were reused in four consecutive reactions without the loss of activity and selectivity, respectively.

In this study the fungal laccase from Myceliophthora thermophila (Novozym® 51003) was investigated for oxidative CC couplings of phenolic compounds. This enzyme requires only molecular oxygen as oxidant, which represents a great advantage for oxidative coupling reactions. However, such couplings are typically considered as highly unselective, due to the radical reaction mechanism of laccases. Based on different analytical techniques we gained detailed insights into laccase initiated coupling reactions. A preselection of potential substrates was realized via oxygen measurement during laccase initiated oxidations. Furthermore in situ FT-IR spectroscopy facilitated analyses in-depth, due to feasibility to detect dissolved as well as solid compounds. This technique allowed the detection of the grade of couplings of various laccase substrates, depending on different conditions. As a result oxidative dimerizations of 2,6-disubstituted phenols could be identified as highly selective and were scaled-up to multigram scale. Thereby the oxidation product of 2,6-diisopropyl phenol can be easily reduced to the corresponding biphenol, the antibacterial agent dipropofol. The presented techniques open up new biocatalytical approaches receiving quinoid units as key elements of many natural compounds and pharmaceuticals.

Quenching in vaporising liquids is mostly affected by the Leidenfrost effect, causing avoidable residual stresses and distortion. Molten salts and molten metals provide a quenching without any Leidenfrost effect, but need to be operated at high bath temperatures with a high effort for cleaning the quenched components. In this work ionic liquids (salts with melting temperatures below 100 °C) are investigated as quenching media with respect to cooling power, homogeneity and thermal stability. Aluminium and steel cylinders have been quenched in baths of different ionic liquids with varying compositions and bath temperatures showing almost no Leidenfrost effect. The time-temperature curves have been recorded and the heat transfer coefficients were determined. It was shown, that the cooling power of ionic liquids could be increased by limited water addition without any Leidenfrost effect and is sufficiently fast even for quench sensitive alloys. Further investigations on aluminium samples with a complex profile show that quenching in ionic liquids causes less distortion compared to water quenching.

The polysaccharide laminarin (β-1,3-glucan) is used as a long-term carbon storage compound in brown algae. This chemical storage form of carbon enables perennial brown algae in seasonally fluctuating ecosystems to uncouple growth from photosynthesis, i.e., most of these plants grow as seasonal anticipators in winter based on remobilization of laminarin, while in summer, growth typically ceased to fill up the storage pool. Because of this high ecological relevance, a reliable and precise method for determination and quantification of laminarin is needed. Therefore, a simple, efficient, cold water extraction method coupled to a new quantitative liquid chromatography-mass spectrometrical method (LC-MS) was developed. Laminarin was determined in 9 out of 12 brown algal species, and its expected typical molar mass distribution of 2000–7000 Da was confirmed. Furthermore, laminarin consisted of a complex mixture of different chemical forms, since 15 chemical laminarin species with distinct molecular weights were measured in 9 species of brown algae. Differences in chain length and number of laminarin species seem to be species specific and hence may indicate some chemotaxonomic value. Laminarin concentrations in the algal tissues ranged from 0.03 to 0.86 % dry weight (DW). The direct chemical characterization and quantification of laminarin by LC-MS represents a powerful method to verify the biochemical and ecological importance of laminarin for brown algae.

Drug-coated balloon catheters are a novel clinical treatment alternative for coronary and peripheral artery diseases. Calcium alginate, poly(vinylethylimidazolium bromide) and polyacrylamide hydrogels were used as vessel models in this in vitro study. In comparison to a simple silicone tube their properties can be easily modified simulating different types of tissue. Local drug delivery after balloon dilation in the first crucial minute was determined in a vessel-simulating flow-through cell by a simulated blood stream. Balloon catheters were coated with paclitaxel using the ionic liquid cetylpyridinium salicylate as a novel carrier. Drug transfer from coated balloon catheters to different simulated vessel walls was evaluated and compared to a silicone tube. The highest paclitaxel delivery upon dilation was achieved with calcium alginate as the vessel model (60%) compared to polyacrylamide with 20% drug transfer. The silicone tube showed the least amount of wash-off (

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Application of light as a trigger for remote control of enzyme activation offers high temporal and spatial resolution. A known enzymatic system based on an acid phosphatase and 6-chloro-8-fluoro-4-methylumbelliferone phosphate as substrate is employed to study different strategies for improving the time resolution of enzyme activation by a light-induced pH jump. Hence, a single laser pulse excitation with a pulse duration of 6 ns resulted in a 4-fold enzyme activation by instantaneous proton release through the rearrangement of 2-nitrobenzaldehyde. The time resolution of the activation experiment is now limited only by the detection system, no longer by the excitation step. In addition, halogenated 2-nitrobenzaldehydes are tested for their suitability as phototriggers and a detailed study of the pH-dependent kinetics of the enzymatic reaction is performed, which reveals that the substrate can probably only bind to the enzyme in its monoanionic form.

Recovery of carbohydrates from aqueous solution represents a problem due to their large, multivalent and flexible structure and their high hydrophilicity. Organic solvents as well as alternative solvents such as ionic liquids are able to extract carbohydrates from aqueous media by the aid of primary amines. The mechanism of the extraction process has been explored by using galactose and its corresponding O -methyl galactoside. The results indicate that the mechanism is based on formation of an adduct between the aldo -structure of the monosaccharide and the primary amine to provide a hemiaminal, which is extracted into the organic phase. The extraction rate can be influenced by variation of temperature, time, and the amount of amine and depends on the structure of the carbohydrate. The selectivity can also be tuned using different types of ionic liquids. This procedure opens the possibility to recover a carbohydrate selectively from a mixture of different carbohydrates.

Enzymes on carriers can be easily recycled or used in fixed bed reactors. The immobilization often results in an improved stability. Depending on the support used and the method of coupling, this is a time-consuming process. While the wide applicability of microwaves (MWs) within organic synthesis is known since the 1980s, proteins (including enzymes) are generally considered as too sensitive toward MW irradiation. In this article, MW methods were investigated to improve the processing speed of covalent enzyme immobilization on inorganic supports. Herein two laccases from Trametes versicolor and Myceliophthora thermophilia (Novozyme 51003®) and the glucose oxidase from Aspergillus niger were immobilized onto samples of ceramic honeycomb and porous glass (TRISOPERL® 1000 AMINO). The enzymes showed different sensitivity to MW irradiation, but all were suitable for MW-assisted immobilization. Subsequent stability tests were conducted to compare conventional immobilization methods with those with MW irradiation. The glucose oxidase provided the best results. For all cases, a successful MW irradiation assisted covalent enzyme immobilization on solid support was obtained with a total 20-fold reduction of the time necessary.