Spectroscopic study and catalytic evaluation of mesostructured Al-MCM-41 and Pt/H3PW12O40/Al-MCM-41 catalysts

Environmentally benign and highly regioselective ring opening of epoxides accelerated by ultrasound irradiation

“…On the other hand, introducing chromium and manganese ions into the MCM-41 surface led to reduce surface area of catalysts and as shown in Table 1, these catalysts afforded the desired products only in moderate yields ( Table 1, entries 5 and 6). The higher catalytic activity of Al-MCM-41 is attributed to the presence of acidic sites arising from the AlO 4 tetrahedral units in the framework (14) and the desired product 3a could be obtained in isolated yields of 64% (Table 1, entry 4). However, MCM-41 could efficiently catalyze the ring opening reaction of epoxides to afford the desired products in higher yields and relatively shorter reaction time (Table 1, entry 3).…”

“…This heterogeneous solid acid catalyst has shown versatile usage and widely applied in the synthesis of various chemicals due to their well-defined micro-structure which forms the basis of uniform active sites and well-controlled steric effects, high acid strength, hydrophilic and hydrophobic properties and reusability that make them promising candidates for catalytic applications (8,9). Therefore, several derivatives of MCM-41 including Mn(bpdo) 2 Cl 2 /MCM-41 (10), Mn-MCM-41 (11,12), Cr-MCM-41 (13) and Al-MCM-41 (14) have been prepared and utilized to catalyze various reactions.…”

Esterification of levulinic acid into hexyl levulinate over dodecatungstophosphoric acid anchored to Al-MCM-41

“…[21À25] Till now, several groups have worked on the heterogeneous catalysts consisting of 12-tungstophosphoric heteropoly acid (H 3 PW 12 O 40 , HPW) and Al-MCM-41. For example, Wang et al [26] prepared Al-MCM-41 from tetraethylorthosilicate (TEOS) and aluminum tri-sec-butoxide and then used it to prepare Pt/H 3 PW 12 O 40 /Al-MCM-41 catalysts. Yang et al [27] also prepared Pt/H 3 PW 12 O 40 /Al-MCM-41 catalysts, in which Al-MCM-41 was prepared from fumed silica and aluminium sulphate.…”

Influence of Cs Substitution on the Structural Properties and Catalytic Performance of Ni-H₃PW₁₂O₄₀/SiO₂ Catalysts

“…Heteropolyacids (HPAs) with Keggin structure and their salts have been widely investigated as catalysts in many oxidation and acid-catalyzed reactions due to their strong acidity, high oxidation potential, and redox character. [8][9][10][11][12] The tungstophosphoric acid (H3PW12O40) (HPW) is among the most extensively studied, [13][14][15] since it possesses the highest Brønsted acidity. Nevertheless, the main drawback of such materials for catalytic application is their low specific surface area (<10 m 2 • g -1 ).…”