Facile in situ Syntheses of Highly Water‐Stable Acidic Sulfonated Mesoporous Silica without Surfactant or Template

Abstract

A new simple method to prepare acidic mesoporous sulfonated silica in situ without any surfactant is reported. The prepared catalysts were characterized by XRD, nitrogen adsorption, thermogravimetric analysis (TGA), and elemental analysis. The concentration of –SO3H groups was measured by titration, and FTIR was applied to confirm the successful incorporation of the strong acid sites. The in situ sulfonated silica (ISS) has a large surface area with a narrow range of mesoporosity and good thermal stability. Moreover, the preparation method has the advantage of easy control of the acid concentration and versatile synthesis. The ISS was used in catalytic hydrolysis and showed remarkable reusability even under very harsh conditions. The butylation of phenol was conducted over ISS to utilize the mesoporosity of the catalysts. Finally, the ISS catalysts might be used in various acid catalyses owing to the advantages of their simple/inexpensive preparation, reusability, and mesoporosity.

A Series of UiO-66(Zr)-Structured Materials with Defects as Heterogeneous Catalysts for Biodiesel Production

“…Biodiesel production applying solid catalysts could enable the establishment of an effective and continuous procedure and improve the economy of biodiesel production . In this regard, some heterogeneous catalysts have been synthesized to enhance transesterification reactions including earth metal oxides, single and mixed oxides, zeolites, hydrotalcites, zirconium oxides, ion-exchange resins with (−SO 3 H) groups, and acid-functionalized silica . Although the abovementioned catalysts in the biodiesel synthesis are active, they possess some drawbacks like the required high temperature and long reaction time, low mass transfer of reactant owing to the smallest surface area, the small pore diameter, and less active sites …”

“…10 In this regard, some heterogeneous catalysts have been synthesized to enhance transesterification reactions including earth metal oxides, 14 single and mixed oxides, 15 zeolites, 16 hydrotalcites, 17 zirconium oxides, 18 ion-exchange resins with (−SO 3 H) groups, 19 and acid-functionalized silica. 20 Although the abovementioned catalysts in the biodiesel synthesis are active, they possess some drawbacks like the required high temperature and long reaction time, low mass transfer of reactant owing to the smallest surface area, the small pore diameter, and less active sites. 21 In view of these obstacles, metal−organic frameworks (MOFs) can be described as crystalline porous solid materials have received significant consideration as of late because of their points of interest, for example, high surface area, permanent porosity, and rich metal sites.…”

Expanded perlite: an inexpensive natural efficient heterogeneous catalyst for the green and highly accelerated solvent-free synthesis of 5-substituted-1H-tetrazoles using [bmim]N3 and nitriles

“…Therefore, replacement of environmentally hazardous catalysts with non-toxic, effectual and reusable catalysts that have been associated with great reactivity, operational simplicity and noncorrosive nature is highly desired. [1][2][3][4][5][6][7][8][9][10][11] On the other hand removing solvent from the reaction medium is a safety subject, while solvents are potentially toxic. Hence, utilizing the solventfree procedures is one of the proper options, particularly with respect to the E-factor.…”

Natural Phosphate Supported Titania as a Novel Solid Acid Catalyst for Oleic Acid Esterification

“…Ion-exchange resins such as Amberlyst-15 and Nafion-NR50 had been successfully demonstrated as excellent acid catalysts for FFA esterification. However, these catalysts are expensive and show bad stability. , Several other solid acid catalysts were investigated in biodiesel production by esterification of fatty acids; some examples include clays, heteropolyacids, , metal-containing molecular sieves, , metal–organic framework based solid acids, , acid functionalized silica/mesoporous silica, , mesoporous carbon based solid acids, − and zeolites . Unfortunately, many of the aforementioned catalysts encounter several issues such as low surface area and small pore size and serious catalyst leaching. , …”