Polyethylene glycol clicked Co(II) Schiff base and its catalytic activity for the oxidative dehydrogenation of secondary amines

Copper catalyzed [3+2] cycloaddition "click method" provided an efficient and high yielding immobilization of cobalt(II) Schiff base to the azido-functionalized MeOPEG(5000); whereas the direct reaction between MeOPEG(5000) and Co(II) Schiff base did not produce any immobilization. The prepared catalyst was tested for the oxidative dehydrogenation of various secondary amines using TBHP as oxidant and could be easily recovered by precipitation with diethyl ether at the end of the reaction.     

Investigation of the Three-Nucleon System Dynamics in the Deuteron–Proton Breakup Reaction

Precise and large sets of cross section, vector A _x , A _y and tensor A _xx , A _xy , A _yy analyzing power data for the ¹ H(d, pp)n breakup reactions were measured at 100 and 130 MeV deuteron beam energies with the SALAD and BINA detectors at KVI and the Germanium Wall setup at FZ-Jülich. Results are compared with various theoretical approaches which model the three-nucleon system dynamics. The cross section data reveal a sizable three-nucleon force (3NF) and Coulomb force influence. In case of the analyzing powers very low sensitivity to these effects was found and the data are well describe by 2N models only. For A _xy at 130 MeV, serious disagreements were observed when 3NF models are included in the calculations.     

Interaction of highly nonlinear solitary waves with thin plates

We investigate the reflection of highly nonlinear solitary waves in one-dimensional granular crystals interacting with large plates. We observe significant changes in the reflected waves’ properties in terms of wave amplitude and time of flight in association with the intrinsic inelasticity of large plates, which are governed by the plate thickness and the size of the granular constituents. We also study the effects of fixed plate boundaries in the formation of reflected waves, and find the existence of a critical distance, within which the interaction between the granular chain and plate is strongly modified. We explain the effects of intrinsic inelasticity and of boundaries in the large plates by using plate theory and the contact mechanics between a plate and a spherical striker. We find that experimental results are in excellent agreement with the analytical predictions and numerical simulations based on the combined discrete element and spectral element models. The findings in this study can be useful for the nondestructive evaluation of plate structures using granular crystals, which can improve the resolution of in-situ, portable measurement instruments leveraging high acoustic energy and sensitivity of solitary waves.     

Effect of feedstock water leaching on ignition and PM1.0 emission during biomass combustion in a flat-flame burner reactor

In this work, the effects of feedstock water leaching on ignition and PM_1.0 emission during biomass combustion were studied, for the first time, in a Hencken flat-flame burner reactor (HFFBR). A high-speed video camera and high-resolution electrical low-pressure impactor were respectively employed to diagnose ignition and PM_1.0 along the height of the burner. The mineral composition of PM₁₀₊ was measured as a function of height to demonstrate the potassium release during the early stage of biomass combustion. The results show that water leaching does not change the functional group of the biomass (straw), but increases the BET surface area and pore volume. Water leaching removes 90% of the potassium and all the chlorine, reducing the same amount of PM_1.0 emission. The effect of water leaching on ignition delay observed in the flat-flame burner reactor agrees with the delay of biomass-devolatilization in TGA. Profiles of mineral composition in the PM₁₀₊ with height shows that a large amount of the potassium is released before biomass ignition. This indicates that, at realistic heating rates, the catalytic promotion of water-soluble minerals on biomass ignition is primarily through promoting devolatilization. The ignition delay of biomass particles caused by water leaching is more significant at lower temperature, e.g., ignition is delayed from 20 to 24?ms at 1000?°C, and from 9.2 to 10.2?ms at 1300?°C.     

Graphene Oxide Supported Molybdenum Cluster: First Heterogenized Homogeneous Catalyst for the Synthesis of Dimethylcarbonate from CO2 and Methanol

The octahedral molybdenum cluster‐based compound, Cs₂Mo₆Brⁱ₈Br^a₆ was immobilized on graphene oxide (GO) by using a facile approach. High resolution transmission electron microscopy results revealed that molybdenum clusters were uniformly distributed on the GO nanosheets. Cs₂Mo₆Brⁱ₈Br^a₆ was attached to the GO support via chemical interaction between apical ligands of Mo₆Brⁱ₈Br^a₆ cluster units and oxygen functionalities of GO, as revealed by XPS studies. The developed material was used for the synthesis of dimethyl carbonate by reduction of carbon dioxide. The synthesized catalyst, that is, GO–Cs₂Mo₆Brⁱ₈Br^a_x, exhibited higher catalytic efficiency than its homogeneous analogue without using dehydrating agent. The catalyst was found to be efficiently recyclable without significant loss of catalytic activity.     

Investigations of Few-Nucleon System Dynamics in Medium Energy Domain

Precise and large set of cross sections, vector A _x , A _y and tensor A _xx , A _xy , A _yy analyzing powers for the ¹ H(d, pp)n breakup reactions were measured at 100 and 130 MeV deuteron beam energies with the use of the SALAD and BINA detectors at KVI and Germanium Wall setup at FZ-Jülich. Results are compared with various theoretical approaches which model the three-nucleon (3N) system dynamics. The calculations are based on different two-nucleon (2N) potentials which can be combined with models of the three-nucleon force (3NF) and other pieces of the dynamics can also be included like the Coulomb interaction and relativistic effects. The cross sections data reveal seizable 3NF and Coulomb force influence. In case of analyzing powers very low sensitivity to the effects was found and the data are well describe by 2N models only. At 130 MeV for A _xy serious disagreements appear when 3NF models are included into calculations.     

Cyclotriphosphazene grafted silica: a novel support for immobilizing the oxo-vanadium Schiff base moieties for hydroxylation of benzene

The first report on the use of chlorotriphosphazenyl anchored mesoporous silica as a novel support for the immobilization of oxo-vanadium Schiff base moieties is described. The resulting heterogeneous material showed better catalytic activity than homogeneous as well as silica immobilized oxo-vanadium Schiff base for the hydroxylation of benzene with hydrogen peroxide.