The partial oxidation of C4–C6 alkanes to maleic anhydride, 2-methyl maleic anhydride, and acetic acid over MoVO catalysts

Abstract

Alkanes such as iso-butane, n-pentane, and cyclohexane have been converted effectively to maleic anhydride, 2-methyl maleic anhydride, and acetic acid over MoVO catalysts below 330°C. In order to explore the possible reaction pathways, the oxidation of iso-butene, cyclohexene, 2-methyl-1-propanol, tert-butanol, and 2-methylacrylic acid were examined over the catalysts. In isobutene oxidation, acetic acid and 2-methyl maleic anhydride were detected but not maleic anhydride. In cyclohexene oxidation, benzene and phenol were detected as major products but it was not the case in cyclohexane oxidation. The results of our investigation indicate that the oxidation pathway of iso-butane is different from that of iso-butene, 2-methyl-1-propanol, tertbutanol, and 2-methylacrylic acid, whereas the oxidation pathway of cyclohexane is different from that of cyclohexene.

Mo-V-O Based Electrocatalysts for Low Temperature Alcohol Oxidation

“…Hydrothermal conditions utilized in this synthesis were necessary for the complete rearrangement of the reactants in order to ensure that phase pure materials were obtained . Many variants of the Mo-V-O system have been reported. − , However, the products from the hydrothermal approach used here were matched to Mo 0.97 V 0.95 O 5 (JCPDS 00–050–0535) with a triclinic unit cell, TeO 0.33 Mo 0.75 V 0.25 O x (JCPDS 00–055–0700) with an orthorhombic unit cell, and (TeO) 0.39 (Mo 3.52 V 1.06 Nb 0.42 )­O 14 (JCPDS 00–058–0789) with an orthorhombic unit cell. The orthorhombic structure in these Mo-V-(M)-O systems correspond to the M1 phase which has been previously shown to be the active phase for the high temperature alkane oxidation reactions .…”

“…8−11 Mo-V-(M)-O based catalysts have been utilized in oxidation reactions, such as benzene to maleic anhydride, acrolein to acrylic acid, and propane to acrylic acid. 10 Selective alkane oxidation has been observed at elevated temperatures above 300 °C on these catalysts. Due to this relatively high reaction temperature, there is a low selectivity for the targeted products accompanied by the formation of many byproducts.…”

“…Currently, the catalytic oxidation is not commercialized due to the low selectivity of the desired products with the presence of byproducts that are difficult to separate. 10 This study examines the use of Mo-V-(Te,Nb)-O catalysts to perform low-temperature electrooxidation of cyclohexanol. Hydrothermal conditions were used in the synthesis of the Mo-V-(Te,Nb)-O based catalyst to facilitate the isolation of the single pure orthorhombic M1 phase.…”

“…Due to this relatively high reaction temperature, there is a low selectivity for the targeted products accompanied by the formation of many byproducts . Also scale up is difficult, and economically unacceptable …”

“…Molybdenum-based oxides have been extensively researched for the selective oxidation of alkanes over several decades. − Mo-V-(M)-O based catalysts have been utilized in oxidation reactions, such as benzene to maleic anhydride, acrolein to acrylic acid, and propane to acrylic acid . Selective alkane oxidation has been observed at elevated temperatures above 300 °C on these catalysts.…”