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.

Hydrophilic silica nanoparticles (100 nm in length and of 20 nm diameter) and larger hollow Halloysite nanotubes (HNTs; 800 nm in length with an outer diameter of 50 nm and an inner diameter of 15 nm) are used to stabilize an oil-in-water emulsion. These particle-stabilized Pickering emulsions (PEs) are used for the hydroformylation of a long-chain olefin (1-dodecene). Rhodium (Rh) and the water-soluble ligand sulfonated 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene are used as catalyst. The emulsions are prepared by sonication and Ultra-Turrax in a specially designed vessel to protect the catalyst from oxygenation and to control the temperature of each sample during the preparation process. The Rh catalyst shows interfacial active behavior and strongly influences the mean droplet size of the emulsions, stability, wettability, and energy of detachment. Further, the Rh catalyst stabilizes an emulsion even in the absence of particles. In a mixture of Rh catalyst and particles, both attach at the interface if the droplet size is in a magnitude of micrometers. These PEs show a monotonous droplet decrease with increasing particle concentration. It is shown that hydroformylation is possible in all emulsions stabilized by the Rh catalyst, silica nanoparticles, or HNTs. However, the conversions in the emulsions are different. The highest conversion is observed in silica-stabilized emulsions with above 40 wt % after a reaction time of only 5 h. Further, high selectivity for aldehyde was observed for all emulsions. A model for the behavior of the emulsions in the reactor is postulated. Interestingly, the emulsions stabilized by the Rh catalyst and silica nanoparticles are destroyed after the reaction, but the HNTs-stabilized PEs remained stable.

The hydroformylation of 1-dodecene was performed in microemulsion systems using rhodium sulfoxantphos as a catalyst. Preliminary experiments proved these aqueous multiphase systems to enable the reaction with good yield and very high selectivity toward the linear aldehyde (about 60% yield with n:iso ratio of 98:2 after 24 h reaction time). Catalyst recycling is easily possible by simple phase separation after the reaction, maintaining the activity and very high selectivity. The investigation of process parameters showed a first-order dependence of the initial rate with respect to the 1-dodecene concentration, and a more complex behavior with respect to catalyst concentration and syngas pressure. On the basis of an earlier proposed mechanism and the gained experimental data, an adapted kinetic model has been derived, including the unique influences of the regarded multiphase system on the reaction (in particular the surfactant concentration and ligand to metal ratio). The identified model formulation and parameter set for the reaction system enabled the calculation of reaction trajectories that are in good accordance to the observed trends from experimental data.

Demand response is a viable concept to deal with and benefit from fluctuating electricity prices and is of growing interest to the electrochemical industry. To assess the flexibility potential of such processes, a generic, interdisciplinary methodology is required. We propose such a methodology, in which the electrochemical fundamentals and the theoretical potential are determined first by analyzing strengths, weaknesses, opportunities, and threats. Afterward, experiments are conducted to determine selectivity and yield under varying loads and to assess the additional long-term costs associated with flexible operation. An industrial-scale electrochemical process is assessed regarding its technical, economic, and practical potential. The required steps include a flow sheet analysis, the formulation and solution of a simplified model for operation scheduling under various business options, and a dynamic optimization based on rigorous, dynamic process models. We apply the methodology to three electrochemical processes of different technology readiness levelsthe syntheses of hydrogen peroxide, adiponitrile, and 1,2-dichloroethane via chloralkali electrolysisto illustrate the individual steps of the proposed methodology.

In this study, first-row transition metal-doped calcium oxide materials (Mn, Ni, Cr, Co., and Zn) were synthesized, characterized, and tested for the OCM reaction. Doped carbonate precursors were prepared by a co-precipitation method. The synthesis parameters were optimized to yield materials with a pure calcite phase, which was verified by XRD. EPR measurements on the doped CaO materials indicate a successful substitution of Ca2+ with transition metal ions in the CaO lattice. The materials were tested for their performance in the OCM reaction, where a beneficial effect towards selectivity and activity effect could be observed for Mn, Ni, and Zn-doped samples, where the selectivity of Co- and Cr-doped CaO was strongly reduced. The optimum doping concentration could be identified in the range of 0.04-0.10 atom%, showing the strongest decrease in the apparent activation energy, as well as the maximum increase in selectivity.

In this paper, a finite element (FE) modeling is used to model effects of the arterial stiffness on the different signal patterns of the pulse transit time (PTT). Several different breathing patterns of the three subjects are measured with PTT signal and corresponding finite element model of the straight elastic artery is applied. The computational fluid-structure model provides arterial elastic behavior and fitting procedure was applied in order to estimate Young?s module of stiffness of the artery. It was found that approximately same elastic Young?s module can be fitted for specific subject with different breathing patterns which validate this methodology for possible noninvasive determination of the arterial stiffness. [Projekat Ministarstva nauke Republike Srbije, br. III-41007 i br. OI-174028 and FP7 ICT-2007-2-5.3 (224297) ARTreat project]

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Margaret Atwood's Maddaddam trilogy depicts a civilization devastated by a lethal virus developed in a laboratory. The portrayal of isolated and marginalized individuals who perpetrate the construction of the virus, as well as the state of crisis and fear immanent to the apocalyptic narrative, lead to the analysis of the trilogy in reference to the social conditions following the 9/11 terrorist attacks. The New historical conception of literature as an equal participant of the process of circulation of the historical and cultural practices provides grounds for the interpretation of the novels within the field of a public imaginary which stems from the equalization of the terrorist threat with undefeatable contagious diseases. However, the trilogy's cooperation with the system it attempts to uncover will hinder its subversive property and a critical distance. Despite its employment of parody in order to unveil the system, the trilogy (re)enforces the space where fear and apocalyptic thought dwell, therefore obstructing its separation and corroborating the culture of fear and terror it originated from.