Chemical Oxidation of Dibenzothiophene with a Directly Combined Amphiphilic Catalyst for Deep Desulfurization

Probing the Catalytic Activity of Sulfate-Derived Pristine and Post-Treated Porous TiO2(101) Anatase Mesocrystals by the Oxidative Desulfurization of Dibenzothiophenes

Mesocrystals (basically nanostructures showing alignment of nanocrystals well beyond crystal size) are attracting considerable attention for modeling and optimization of functionalities. However, for surface-driven applications (heterogeneous catalysis), only those mesocrystals with excellent textural properties are expected to fulfill their potential. This is especially true for oxidative desulfuration of dibenzothiophenes (hard to desulfurize organosulfur compounds found in fossil fuels). Here, we probe the catalytic activity of anatases for the oxidative desulfuration of dibenzothiophenes under atmospheric pressure and mild temperatures. Specifically, for this study, we have taken advantage of the high stability of the (101) anatase surface to obtain a variety of uniform colloidal mesocrystals (approximately 50 nm) with adequate orientational order and good textural properties (pores around 3-4 nm and surface areas around 200 m²/g). Ultimately, this stability has allowed us to compare the catalytic activity of anatases that expose a high number of aligned single crystal-like surfaces while differing in controllable surface characteristics. Thus, we have established that the type of tetrahedral coordination observed in these anatase mesocrystals is not essential for oxidative desulfuration and that both elimination of sulfates and good textural properties significantly improve the catalytic activity. Furthermore, the most active mesocrystals have been used to model the catalytic reaction in three-(oil-solvent-catalyst) and two-phase (solvent-catalyst) systems. Thus, we have been able to observe that the transfer of DBT from the oil to the solvent phase partially limits the oxidative process and to estimate an apparent activation energy for the oxidative desulfuration reaction of approximately 40 kJ/mol in the two-phase system to avoid mass transfer limitations. Our results clearly establish that (101) anatase mesocrystals with excellent textural properties show adequate stability to withstand several post-treatments without losing their initial mesocrystalline character and therefore could serve as models for catalytic processes different from the one studied here.

Direct preparation of [(CH3)3NC16H33]4Mo8O26 and its catalytic performance in oxidative desulfurization

The catalyst [(CH₃)₃NC₁₆H₃₃]₄Mo₈O₂₆ has been synthesized by a direct precipitation method and shows efficient oxidative desulfurization performance.

Performances, kinetics and mechanisms of catalytic oxidative desulfurization from oils

Ultra-deep desulfurization technologies are critical for cleaner oils and consequent better air quality.

Surfactant encapsulated palladium-polyoxometalates: controlled assembly and their application as single-atom catalysts

Two kinds of assembly structures (nanorolls and hollow spindles) based on the palladium substituted Wells–Dawson polyoxometalate (Pd-POM) were synthesised and showed high catalytic activity for both the Suzuki–Miyaura coupling reaction and semihydrogenation reaction.

The challenge with single-atom catalysts (SACs) is in designing a highly definite structure with accurate location of the single atom and high catalytic efficiency. The noble metal substituted polyoxometalates seem to be a kind of SAC because of their well resolved crystal structure. Here, we got two kinds of assembly structures (nanorolls and hollow spindles) based on the palladium substituted Wells–Dawson polyoxometalate (Pd-POM), which consists of isolated Pd atoms. Both the nanorolls and hollow spindles showed high catalytic activity for both the Suzuki–Miyaura coupling reaction and semihydrogenation reaction. The difference of the chemical surroundings between the nanorolls and hollow spindles leads to their discrepancy in the catalytic activity of semihydrogenation.

Polyoxometalate-based metal–organic coordination networks for heterogeneous catalytic desulfurization

Single crystals and nanocrystals of polyoxometalate-based metal-organic coordination networks for heterogeneous catalytic desulfurization.

Review of Advanced Technology of Flue Gas Desulphurization

Sulfur dioxide is a strong pungent odor and astringency of the colorless gas. The human being health will be threatened as the concentration of sulfur dioxide at atmosphere achieve-ups to 1.4 mg/m3. The technology of flue gas desulphurization will more and more be concerned because of "coal-fog" discharged onto the air in China. This paper demonstrated the latest research results of technology of flue gas desulphurization based on SO2 controlled approaches which can be divided into three stages for combustion that are the prior, middle and later. The advantages and disadvantages of various methods were also described. The three techniques had been reviewed according to the needs and conditions of recovery, comprehensive utilization of sulfur resource. The research results show that the technique of desulphurization after combustion is a large-scale commercial application means to the control of SO2 pollution around world.

Study on the heterogeneous degradation of chitosan with H(2)O(2) catalyzed by a new supermolecular assembly crystal: [C(6)H(8)N(2)](6)H(3)[PW(12)O(40)].2H(2)O

A new supermolecular assembly crystal, [C(6)H(8)N(2)](6)H(3)[PW(12)O(40)].2H(2)O (DMB-PWA), was synthesized with phosphotungstic acid (PWA) and 1,2-diaminobenzene (DMB) under hydrothermal conditions and was characterized by Fourier-transform infrared spectra (FTIR) and single-crystal X-ray diffraction analysis. DMB-PWA could effectively catalyze oxidative degradation of chitosan with H(2)O(2) in the heterogeneous phase. The optimum degradation conditions were determined by orthogonal tests as follows: amount of chitosan 1.00 g, 30% (wt %); H(2)O(2), 3.0 mL; dosage of catalyst, 0.06 g; reaction temperature, 85 degrees C; and reaction time, 30 min. The water-soluble chitosan with a viscosity-average molecular weight (M(v)) of 4900 was obtained under the optimum degradation conditions and was characterized by FTIR, ultraviolet-visible diffuse reflection spectra (UV-vis DRS), and X-ray powder diffraction analysis.