Benzylsulfonic acid functionalized mesoporous Zr-TMS catalysts: An efficient and recyclable catalyst for the preparation of coumarin derivatives by Pechmann condensation reaction

Integrated Catalytic Process to Directly Convert Furfural to Levulinate Ester with High Selectivity

“…Reaction conditions: to a 100 mL autoclave with Teflon liner were added furfural (1.5 mL), Pt supported on ZrNb binary phosphate (Zr/Nb, 1:1; treated at 673 K in air; Pt loading: 2.0 wt %; 0.2 g), and absolute ethanol (8.5 mL). Solid acid catalysts have been extensively explored based on various solid materials such as zeolites, [16] nafion-H, [17] amberlyst, [18] montmorillonite K 10, [19] poly(anilinesulfate) salt, [20] heteropoly acids, [21] functionalized mesoporous silica, [22] and metal oxides or modified metal oxides. Results of screening experiments over various alcohol solvents.…”

Coumarins Preparation by Pechmann Reaction Under Ultrasound Irradiation. Synthesis of Hymecromone as Insecticide Intermediate

“…For these reasons, there have been some attempts to find alternative, environmentally benign synthetic routes using a simple, cheap and reusable catalyst for the synthesis of coumarins [8]. With regard to that, a large variety of heterogeneous solid acids such as zeolite Beta, Nafion-H, Amberlyst [9], functionalized mesoporous Zr-TMS [10], [13] and heteropolyacids [14], [15] have been investigated. Ionic liquids [16] or microwave irradiation under solvent-less conditions have also been reported [17].…”

Melamine trisulfonic acid as a new, efficient and reusable catalyst for the solvent free synthesis of coumarins

“…Generally, the Pechmann reaction is carried out by the [24], polyaniline supported acid catalyst [25], ZrCl 4 [26], TiCl 4 [27], Wells-Dawson hetropolyacid [28], nano-crystalline sulfated zirconia-microwave [29] and benzylsulfonic acid functionallized mesoporous Zr-TMS [30]. The main disadvantages of the processes using these catalysts are, long reaction times, low yields, harsh reaction conditions, nonreusability of the catalyst, use of excess amounts of the reagent, strictly reactive conditions (N 2 atmosphere), special efforts required to prepare the catalyst and tedious work-up procedures.…”