Deep oxidative desulfurization of benzothiophene and dibenzothiophene with a peroxophosphotungstate–ionic liquid brush assembly

A novel, efficient and reusable heterogeneous catalytic assembly of peroxophosphotungstate held in an ionic liquid brush was synthesized and an extraction and catalytic oxidative desulfurization (ECODS) procedure was developed for a model oil of benzothiophene (BT) and dibenzothiophene (DBT) using 30 wt% hydrogen peroxide as terminal oxidant and methanol as solvent under mild conditions. Several factors that affect sulfur removal were investigated in detail. The highest sulfur removal can reach 100% for BT in 7 h at 70 °C when the molar ratio of H₂O₂, S and catalyst is 10:1:0.025. The sulfur removal for DBT can also reach 100% in 4 h at 50 °C with the same molar ratio of H₂O₂, S and catalyst. The experimental results demonstrate that this ECODS process has no apparent scale‐up effect. The catalyst can be easily recovered (via simple filtration) and recycled five times without a significant decrease in activity. Copyright © 2015 John Wiley & Sons, Ltd.     

Electrochemical determination of trypsin using a heptapeptide substrate self-assembled on a gold electrode

Microchimica Acta - A simple and sensitive electrochemical method was developed for the determination of trypsin by employing a specific heptapeptide (CRRRRRR) as a substrate. The positively...     

An upper bound for the generalized adiabatic approximation error with a superposition initial state

The classical adiabatic approximation theory gives an adiabatic approximate solution to the Schr¨odinger equation(SE)by choosing a single eigenstate of the Hamiltonian as the initial state.The superposition principle of quantum states enables us to mathematically discuss the exact solution to the SE starting from a superposition of two different eigenstates of the time-dependent Hamiltonian H(0).Also,we can construct an approximate solution to the SE in terms of the corresponding instantaneous eigenstates of H(t).On the other hand,any physical experiment may bring errors so that the initial state(input state)may be a superposition of different eigenstates,not just at the desired eigenstate.In this paper,we consider the generalized adiabatic evolution of a quantum system starting from a superposition of two different eigenstates of the Hamiltonian at t=0.A generalized adiabatic approximate solution(GAAS)is constructed and an upper bound for the generalized adiabatic approximation error is given.As an application,the fidelity of the exact solution and the GAAS is estimated.     

Synthesis,structure and photoluminescence properties of Ho3+ doped TTB–BaTa2O6 phosphors

Ho³⁺ doped TTB–BaTa₂O₆ phosphors were produced by the solid state reaction method. XRD analysis confirmed the formation of BaTa₂O₆ single phase which was accomplished by heat treatment at 1425 °C for 20 h. The crystal structure of TTB–BaTa₂O₆ allowed doping concentration of Ho³⁺ ions up to 10 mol%, maintaining a single phase composition. A second phase of HoTaO₄ begins to appear at 15 mol%. The lattice structure and the crystallite sizes changed with the concentration of Ho³⁺. In SEM analysis, it was also shown that BaTa₂O₆ grain sizes changed with the concentration of Ho³⁺. EDS analysis revealed that the Ta/Ba ratio increased on the grains depending on Ho³⁺ concentration. Charge balance of the structure was formulated through the EDS results. In fluorometer analysis, a strong green emission (λ_em = 546.9 nm) was observed in the visible spectral region. The emission increased with the doping concentration of up to 2.5 mol%, and above this level decreased due to concentration quenching.