The implementation of the hydroformylation reaction for the conversion of long-chain alkenes into aldehydes still remains challenging on an industrial scale. One possible approach to overcoming this challenge is to apply tunable systems employing surfactants. Therefore, a novel process concept for the hydroformylation of long-chain alkenes to aldehydes in microemulsions is being investigated and developed at Technische Universität Berlin, Germany. To test the applicability of this concept for the hydroformylation in microemulsions on a larger scale, a miniplant has been constructed and operated. This contribution presents the proof of concept for hydroformylation in microemulsions carried out during a 200 h miniplant operation. Throughout the operation a stable aldehyde yield of 21% and a catalyst loss in the product phase below 0.1 ppm were achieved, which confirms previous lab scale findings. Additionally, solution strategies for a stable continuous operation to overcome challenges such as foaming, phase separation issues, and coalescence dynamics are discussed herein.

Nowadays, the development of chemical processes using environmentally friendly solvents is of high importance. As an alternative to conventional reaction media based on organic solvents, we show a novel aqueous surfactant-based process concept which is used for the three step synthesis of the fungicide Boscalid®. By applying three phase microemulsion systems for the Suzuki coupling reaction, the first step within the Boscalid® synthesis, a simple product and catalyst separation can be achieved, whereby the water-soluble homogeneous Pd/SPhos catalyst complex can be reused several times.Together with an easily recyclable heterogeneous PtIr@TiO 2 catalyst, which is applied for the hydrogenation reaction in the second step, followed by base-assisted condensation to the final product Boscalid® in the third step, overall yields up to 90% are achievable for the whole reaction sequence. This result was obtained without any purification step in between that requires the use of further solvents. In this way the total synthesis costs can be reduced and solvent wastage can be avoided.

The application of microemulsion systems as switchable reaction media for the rhodium-catalyzed hydroformylation of 1dodecene is being reported. The influence of temperature, phase behavior, and the selected nonionic surfactant on the reaction has been investigated. The results revealed that the structure and the hydrophilicity (degree of ethoxylation) of the applied surfactant can have a strong impact on the performance of the catalytic reaction in microemulsion systems, in particular on the reaction rate. The surfactant determines the boundary conditions for catalysis (interfacial area, local concentrations) and can also interact with the catalyst at the oil−water interface and hinder the reaction. In addition to the discussion of the experimental results, we present a proposal for the impact of surfactantbased reaction media on the reaction mechanism of the catalyst reaction.

No abstract

Electron capture dissociation (ECD) has recently been shown in some cases to produce abundant N-terminal b-ion peptide fragments. These product ions are usually only observed when activation occurs via vibrational excitation as in collision-induced dissociation (CID). Here, we show that occurrence of b-ions in the ECD spectra of synthetic peptides are correlated with low gas-phase basicity and that the observed b-ion fragments are N-terminal products. Furthermore, all ECD spectra containing b-ions also had abundant losses of hydrogen and ammonia from the charge-reduced species.

Emulsions stabilized by solid particles are so called Pickering emulsions which are characterized by their high stability against coalescence. This type of emulsion can be used for a lot of applications. Very little is known about how reaction conditions affect their properties. In this study the influence of important reaction conditions like shear stress, pressure, temperature, and the influence of synthesis gas on Pickering emulsions is investigated. It is shown that the emulsions remain stable in terms of coalescence in a broad range of the reaction conditions and are suitable as reaction media for industrial processes and for a reaction optimization with a subsequent separation step.

For the first time, a significant boost in catalytic activity in the rhodium-catalysed hydroformylation of an alkene by using a bidentate bis(N-heterocyclic silylene) ligand is reported. This is shown by the hydroformylation of styrene at 30 bar CO/H 2 pressure in the presence of [HRh(CO)(PPh 3 ) 3 ] with an excess of the ferrocenediyl-based bis-NHSi ligand 4, [({η 5 -C 5 H 4 {PhC(NtBu) 2 }Si}) 2 Fe], which results in superior catalytic activity, compared with the bidentate diphosphines DPPF (3a) and xantphos (3b). In contrast, the hydroformylation of styrene in the presence of [HRh(CO)(PPh 3 ) 3 ] with excesses of the monodentate NHSi ligands [{PhC(NtBu) 2 }SiNMe 2 ] (1) and [{C 2 H 2 (NtBu) 2 }Si:] (2) at 30 bar CO/H 2 pressure revealed consid-[a]

Luminescent erbium-based inorganic-organic hybrid materials play an important role in many frontier nano-sized applications, such as amplifiers, detectors and OLEDs. Here, we demonstrate the possibility to fabricate high-quality thin films comprising both erbium and an appropriate organic molecule as a luminescence sensitizer utilizing the combined atomic layer deposition and molecular layer deposition (ALD/MLD) technique. We employ tris(N,N'diisopropyl-2-dimethylamido guanidinato)erbium(III) [Er(DPDMG)3] together with 3,5pyridine dicarboxylic acid (3,5-PDA) as precursors. With the appreciably high film deposition rate achieved (6.4 Å/cycle), the guanidinate precursor indeed appears as an interesting new addition to the ALD/MLD precursor variety towards novel materials. Our erbium-organic thin films showed highly promising UV absorption properties and a photoluminescence at 1535 nm for a 325 nm excitation, relevant to possible future luminescence applications.