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A very ecofriendly heterogeneous catalytic method has been used for the highly selective synthesis of octahydroaminoacridine/1,2,3,4,5,6,7,8-octahydroacridin-9-amine (OA) by a single-step vapor pha...

An environmentally friendly and efficient hydrothermal method has been used for the synthesis of mesoporous NbSBA-15 materials. To find better hydrothermal stability, the synthesized NbSBA-15 materials have been treated in boiling water and water steam at different temperatures with various times. The NbSBA-15 materials have been characterized by inductively coupled plasma atomic emission spectroscopy (ICP-AES), X-ray diffraction (XRD), N2 adsorption, UV-visible diffuse reflectance spectroscopy (UV−vis DRS), field emission-scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS). To investigate the effect of structural and textural properties with a higher Nb incorporation, NbSBA-15 has also been synthesized at different pH in sol−gel solution. The results of ICP-AES, TEM-EDS, and XPS show that a nSi/nNb ratio up to 6.7 is successfully prepared by changing the nSi/nNb ratio in the synthesis gel at ...

Mesoporous silica molecular sieves MCM-41 containing zinc and aluminum ions (Zn−Al−MCM-41) with Si/(Zn + Al) ratios equal to 75, 151, 228, 304, and 380 and only aluminum ions with Si/Al ratios equal to 21, 42, 62, 83, and 104 were synthesized under hydrothermal conditions using cetyltrimethylammonium (CTMA+) surfactants as templates in the absence of auxiliary organics. The mesoporous materials, viz., Zn−Al−MCM-41 and Al−MCM-41, were characterized using several techniques, e.g., ICP-AES, XRD, FTIR, TG/DTA, nitrogen adsorption, 27Al MAS NMR, SEM, TEM, XPS, and pyridine acidity (TPD and FTIR) measurements. The number of acid sites in Zn−Al−MCM-41 is higher than that in Al−MCM-41 due to the aluminum ion nonframework by the introduction of zinc ions. However, tetrahedral aluminum is replaced by zinc, producing two negative ions with a tetrahedral environment. The ions are associated with Bronsted acid sites, and the tetrahedral aluminum ions become octahedral aluminum ions and are associated with Lewis acid s...