Activity of supported Re2O7 catalysts for the metathesis of methyl oleate

Comparison of metathesis activity of catalysts prepared by anchoring of MoO2(acac)2 on various supports

“…Thus, the efficiency of the latter two systems can be even improved and, without doubts, the MoO 3 /SiO 2 AEAl 2 O 3 -SnMe 4 system exhibits higher specific activity than the MoO 3 / Al 2 O 3 -SnMe 4 one. Better performance after replacing alumina by silica-alumina was also reported for rhenium [3,5] and tungsten [18] systems treated with tetraalkyltin.…”

“…This effect is well recognised for supported rhenium catalysts. Re 2 O 7 /Al 2 O 3 AESiO 2 systems are known to be more active than Re 2 O 7 /Al 2 O 3 ones, whereas Re 2 O 7 /SiO 2 catalyst is inactive in olefin metathesis [1][2][3][4][5][6]. The difference between the activity of rhenium oxide supported on alumina and silica-alumina is explained by different local electronic properties of the carrier [6].…”

On the Product Formation in 1-Butene Metathesis over Supported Tungsten Catalysts

“…They attributed the enhanced performance to the change in the Brønsted acidity of the catalyst and a modification of the interaction between the tungsten species and the support. Similar results have been claimed for supported Re 2 O 7 metathesis catalysts [8,9]. Higher turn-over frequencies have been obtained in Re 2 O 7 -catalysed metathesis using ordered mesoporous alumina (OMA) as a support material rather than conventional aluminas [10][11][12][13].…”

Characterization and catalytic performance of rhenium oxide-based catalysts supported on borated silica-alumina

“…A calculated volume of SnBu 4 (Fluka) dissolved in ca. 0.3 cm 3 of n-heptane (Merck, distilled over Na/benzophenone), was added to the catalyst via a syringe through a rubber septum, always keeping a molar ratio [Sn]:[Re] = 0.55 [13]. Then, 1.5 cm 3 of methyl oleate (Aldrich) was added to the reaction vessel, via syringe.…”

“…18 wt.% Re 2 O 7 ) are needed. On silica-alumina, the most acidic hydroxyl groups (bridging hydroxyl groups) react firstly, and high rhenium loadings (>3 wt.% Re 2 O 7 ) would lead to three-dimensional clusters [12] or to ≡Si-O-ReO 3 sites [13], inactive in metathesis reactions [14].…”