Role of acid centers of Sn/Mo oxide catalyst in propylene conversion to acetone

Effects of tetrahedral molybdenum oxide species and MoOx domains on the selective oxidation of dimethyl ether under mild conditions

“…We have also investigated the effects of whereas its Lewis acidity is ascribed to Sn ions. 35,39,40 Fig. 10 shows that the total amount of acidic sites of the MoO 3 -SnO 2 catalysts are obviously increased from Mo3Sn1 to Mo1Sn3, which was consistent with the NH 3 -IR results.…”

“…Fig.9and 10 show the NH 3 -IR and NH 3 -TPD profiles of the MoO 3 -SnO 2 catalysts with different SnO 2 contents, respectively. Many research studies concerning the acidic properties of oxide catalysts show that the Brønsted acidity of MoO 3 -SnO 2 catalysts is determined by the existence of Mo ions, whereas its Lewis acidity is ascribed to Sn ions 35,39,40. Fig.10shows that the total amount of acidic sites of the MoO 3 -SnO 2 catalysts are obviously increased from Mo3Sn1 to Mo1Sn3, which was consistent with the NH 3 -IR results.…”

FT-IR study of methanol, formaldehyde and methyl formate adsorption on the surface of Mo/Sn oxide catalyst

“…Many papers related to acidic properties of oxide catalysts show that the Brönsted acidity of MoO 3 -SnO 2 catalyst is determined by the presence of Mo ions, whereas its Lewis acidity is attributed to Sn ions [9,10]. According to Ai [4], methanol oxidation to formaldehyde needs the presence of strong Brönsted acidic sites whereas the other surface reactions (dimerization of formaldehyde, disproporcionation of dioxymethylene species and esterification of methoxy group by the formate complex) require the presence of Lewis acid sites and the basic sites.…”

Interaction of hydrocarbons with partial oxidation catalysts

“…The Lewis centres on oxides can adsorb hydrocarbons in two ways: by abstracting a hydride ion from the alkane with formation of a carbonium ion or from the olefin with formation of a radical-cation. 102 The interaction of hydrocarbons with Lewis and Brùnsted centres has been examined, the mechanism of the activation of propene on bismuth molybdate has been discussed, and the role of the acid centres in the activation of the olefin has been demonstrated. 9,11,102,103 The role of the acid centres in the oxidation of propene on the MoO 3 ± Sb 2 O 4 system has been investigated by a spectroscopic method and by the method involving the adsorption of pyridine and ammonia.…”

“…102 The interaction of hydrocarbons with Lewis and Brùnsted centres has been examined, the mechanism of the activation of propene on bismuth molybdate has been discussed, and the role of the acid centres in the activation of the olefin has been demonstrated. 9,11,102,103 The role of the acid centres in the oxidation of propene on the MoO 3 ± Sb 2 O 4 system has been investigated by a spectroscopic method and by the method involving the adsorption of pyridine and ammonia. 104 The relation between the degree of conversion of propene on Brùnsted centres and between the selectivity and the ratio of the concentrations of the Lewis (N L ) and Brùnsted (N B ) centres has been demonstrated.…”