سیلیس سیلیکا مزوزوپور بزرگ به عنوان کاتالیزور پایدار برای واکنش هنری Modulated large-pore mesoporous silica as an efficient base catalyst for the Henry reaction

Introduction Nanostructured materials have attracted great interest because of their tunable structures and broad applications [1–5]. Among variable nanostructures, the development of porous nanostructures is an important research area because of their unique physicochemical properties and applicability such as for adsorption, biomedicine, chromatography, catalysis, energy convergence, and gas storage [6–10]. Variable porous nanostructured materials have been applied in catalysis research areas for elevating the efficiency of the catalytic transformations [11–14]. For instance, mesoporous silica and alumina materials have been used as supports for precious nanoparticles (NPs) catalysts due to their low cost, large surface area and porosity, chemical and thermal stability, mechanical strength, and simple synthesis [15–17]. Mesoporous inorganic materials that supported palladium NPs catalysts have expedited various important reactions [18–20]. Another interesting feature of mesoporous silica is the multitude of possible modifications that can be used for easy organics functionalization to present the desired properties [21, 22]. Mesoporous silica materials functionalized with acidic groups (e.g., –COOH, – SO3H, –SH) and/or basic groups (e.g., –NH2, –NRH, –NR2) have been utilized as non-metallic solid catalysts in various reactions such as cascade reactions [23–25]. These heterogeneous catalysts have the benefits of simple recovery and reuse after the accomplishment of reactions and present green chemical processes in comparison to their homogeneous counterparts [26–28]. Although great efforts have been achieved to develop highly stable and sustainable solid acid/base catalysts, there are still major deficiencies with most matrixes needing rectification including available active catalytic sites, catalytic efficiency, and substrates diffusion [29, 30]. In addition, reactants adsorption and interaction with the functional groups in small pore-size supports restrict the effectiveness of these heterogeneous catalysts [31].