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This work unveils a route for a new generation of heterogeneous polyoxometalate (POMs) based catalysts associated to the preparation of hybrid materials as a triad of POMs, mesoporous silica (SBA‐15) and microporous MOF structures (MOF‐808). The prepared catalyst, PMo12@MOF‐808@SBA‐15, with the main active center the phosphomolybdic acid (PMo12), was successfully applied for the desulfurization of a multicomponent fuel. Its oxidative catalytic performance showed to be considerable superior to the isolated POM@MOF and able to be recycled for more catalytic cycles without active loss. The higher catalytic performance seems to be directly related with the preparation of a more amorphous MOF structure within the channels of SBA‐15, in the presence of active POM guests. [ABSTRACT FROM AUTHOR]

The composites of heteropolyacids (H3PW12, H3PMo12) incorporated into amine-functionalized silica materials were used for the first time as heterogeneous catalysts in the valorization of glycerol (a major waste from the biodiesel industry) through acetalization reaction with acetone. The polyoxotungstate catalyst H3PW12@AptesSBA-15 exhibited higher catalytic efficiency than the phosphomolybdate, achieving 97% conversion and 97% of solketal selectivity, after 60 min at 25 °C, or 91% glycerol conversion and the same selectivity, after 5 min, performing the reaction at 60 °C. A correlation between catalytic performance and catalyst acidity is presented here. Furthermore, the stability of the solid catalyst was investigated and discussed. [ABSTRACT FROM AUTHOR]

The improvement of sustainable chemical processes plays a pivotal role in safe environmental and societal development, for example, by reducing the use of hazardous substances, preventing chemical waste, and improving the efficiency of chemical reactions to obtain added-value compounds. In this context, the porous coordination polymer MOF-808 (MOF, metal–organic framework) was prepared by a straightforward method in water, at room temperature, and was unequivocally characterized by powder X-ray diffraction, vibrational spectroscopy, thermogravimetric analysis, and scanning electron microscopy. MOF-808 material was applied for the first time as catalysts in ring-opening aminolysis reactions of epoxides. It demonstrated high activity and selectivity for reactions of styrene oxide and cyclohexene oxide with aniline, using a very low amount of an eco-sustainable solvent (0.5 mL of EtOH), at 70 °C. Moreover, MOF-808 demonstrated high stability in the catalytic reaction conditions applied, and a notable reuse capacity of up to 20 consecutive reaction cycles, without significant variation in its catalytic performance. In fact, this Zr-based porous coordination polymer prepared by environment-friendly conditions proved to be a novel efficient heterogeneous catalyst, promoting the ring-opening reaction of epoxides under more sustainable conditions, and using a very low amount of catalyst. [ABSTRACT FROM AUTHOR]

An effective and sustainable oxidative desulfurization process for treating a multicomponent model fuel was successfully developed using as a heterogeneous catalyst a composite material containing as an active center the europium Lindqvist [Eu(W5O18)2]9− (abbreviated as EuW10) encapsulated into the nanoporous ZIF-8 (zeolitic imidazolate framework) support. The EuW10@ZIF-8 composite was obtained through an impregnation procedure, and its successful preparation was confirmed by various characterization techniques (FT-IR, XRD, SEM/EDS, ICP-OES). The catalytic activity of the composite and the isolated EuW10 was evaluated in the desulfurization of a multicomponent model fuel containing dibenzothiophene derivatives (DBT, 4-MDBT and 4,6-DMDBT) with a total sulfur concentration of 1500 ppm. Oxidative desulfurization was performed using an ionic liquid as extraction solvent and aqueous hydrogen peroxide as oxidant. The catalytic results showed a remarkable desulfurization performance, with 99.5 and 94.7% sulfur removal in the first 180 min, for the homogeneous active center EuW10 and the heterogeneous EuW10@ZIF-8 catalysts, respectively. Furthermore, the stability of the nanocomposite catalyst was investigated by reusing and recycling processes. A superior retention of catalyst activity in consecutive desulfurization cycles was observed in the recycling studies when compared with the reusing experiments. Nevertheless, the nanostructure of ZIF-8 incorporating the active POM (polyoxometalate) was shown to be highly suitable for guaranteeing the absence of POM leaching, although structural modification was found for ZIF-8 after catalytic use that did not influenced catalytic performance. [ABSTRACT FROM AUTHOR]

The high costs associated with commercially available desulfurization technologies in the refinery industry urge for the development of novel, highly efficient and sustainable alternative processes. On the other hand, the presence of nitrogen compounds significantly decreases the efficiency of the process. Therefore, effective alternative methodologies capable of removing simultaneously sulfur and nitrogen compounds from fuels under economic and sustainable procedures are desirable and needed for the petroleum industry. This work reports a sustainable catalytic process that conciliates oxidation and liquid-liquid extraction to efficiently remove sulfur and nitrogen from fuels. The effective catalytic oxidation was achieved by using a MIL-100(Fe)-based composite encapsulating the phosphomolybdic acid (PMo 12) active center. Complete desulfurization of a multicomponent model fuel containing the most refractory sulfur and nitrogen compounds was achieved after only 30 min. Also, the nitrogen compounds were able to be removed after this short period, mainly by extraction using strategic solvents. The S/N removal process was faster when the expensive ionic liquid [BMIM]PF 6 was replaced by the cost-effective ethanol. Furthermore, the catalyst could be reused in several consecutive desulfurization and denitrogenation cycles, as well as the ethanol extraction solvent was reused for at least four cycles without loss of efficiency. [Display omitted] • PMo 12 @MIL-100(Fe) composite was prepared by the "bottle-around-the ship" approach. • Application as heterogeneous catalyst for simultaneous S/N removal from model fuel. • Remarkable efficiency in simultaneous desulfurization/denitrogenation of model fuel. • Replacement of ionic liquid by ethanol extraction solvent without efficiency loss. • High reusability and stability of heterogeneous catalyst without leaching. [ABSTRACT FROM AUTHOR]