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Although research in renewables is growing at a tremendous rate, the world will still be greatly dependent on fossil fuels for at least the first half of this century. In the quest for more efficient and clean fuels, oil refining companies have turned their attention to processes such as reforming and alkylation technologies; in the latter process, isobutane is reacted with butenes and/or propylenes to produce, among others, branched isooctane, which is the main high-octane component of the gasoline pool. The main benefit of this process is the possibility to produce sulfur-free high-octane fuels, so important economic and environmental advantages are foreseen if investments in this area are realized. This Review analyzes and discusses the most recent progress on catalyst technologies, starting from the traditional sulfuric acid process and proceeding to newly emerging catalyst technologies such as solid acid and ionic liquid-based catalysts. We start with basic mechanistic analyses and conclude this Review with the new nonliquid acid-based commercial and emerging technologies for isobutane alkylation. Emphasis is given to the structure−activity relationships and the advantages and disadvantages present in every discussed catalyst material.

Much has been written about the fundamental aspects of the metal–organic frameworks (MOFs). Still, details concerning the MOFs with structural flexibility are not comprehensively understood. However, a dramatic increase in research activities concerning rigid MOFs over the years has brought deeper levels of understanding for their properties and applications. Nonetheless, robustness and flexibility of such smart frameworks are intriguing for different research areas such as catalysis, adsorption, etc. This manuscript overviews the different aspects of framework flexibility. The review has touched lightly on several ideas and proposals, which have been demonstrated within the selected examples to provide a logical basis to obtain a fundamental understanding of their synthesis and behavior to external stimuli.

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This paper deals with an advanced colorimetric method used to determine the catalase mimetic activity of V2O5 nanoparticles by measuring the decrease in potassium permanganate concentration in a mixture containing V2O5 and hydrogen peroxide. The experiments were carried out in batch reactor at room temperature for 3 min at wavelength number of 525 nm. Vanadium pentoxide was synthesized by hydrothermal method (reflux) from ammonium metavanadate (NH4VO3) as a precursor and cetyltrimethylammonium bromide as a surfactant. The annealing of the product was carried out for 2 h, at temperatures of 250, 500 and 750 °C. In order to determine the structure and the chemical nature of the nanoparticles prepared, the characterization was carried out by X-ray diffraction and scanning electron microscopic techniques. Atomic force microscopic and thermal gravimetric investigations have shown the decomposition steps of V2O5 at different temperatures. UV–visible spectroscopic technique and Fourier transform spectrometry were used to further characterize the nanoparticles. Advanced colorimetric method was used to study the catalase mimetic activity of the newly synthesized vanadium pentoxide (V2O5) nanoparticles using hydrogen peroxide (H2O2) as substrate. V2O5 nanoparticles resulted in an increase in the catalase mimetic activity with increasing the annealing temperature of the V2O5 nanoparticles. The maximum activity was found at 500 °C, which subsequently decreased with further increase in the annealing temperature.

In this research, manganese oxides (MnO 2 ) nanoparticles were prepared by hydrothermal method using KMnO 4 as a precursor. The final brown-black precipitate MnO 2 nanoparticles as prepared, and annealed at different temperatures (250, 450, and 750 °C) were characterized. The nanoparticles prepared were tested for removal of methylene blue (MB), used as a model dye from water. In order to determine the structure and the chemical nature of the MnO 2 nanoparticles prepared, the characterization was carried out by X-ray diffraction. For the surface morphological studies of nanoparticles, field emission scanning electron microscopy was used. In order to study the surface roughness atomic force microscopy was used for determination of the imaging surface structures in the nm scale. Fourier transform infrared spectrometry was used to investigate the vibrations of functional groups in MnO 2 . The tests for dye removal from water using MnO 2 nanoparticles have been carried out for MnO 2 nanoparticles as prepared and annealed at different temperatures. The process parameters such as speed of shaking, reaction time, and MB concentration were studied at 25 °C temperature to determine the best removal efficiency of methylene blue from water. UV/Visible spectrophotometer was used to follow the MB removal. MnO 2 annealed at 750 °C exhibited the highest MB removal efficiency, 89%, as compared with MnO 2 nanoparticles as prepared and annealed at 250 and 450 °C.

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