Kinetic investigation of propane oxidation on diluted Mo1–V0.3–Te0.23–Nb0.125–O x mixed-oxide catalysts

Abstract

Reaction kinetics and proposed mechanism for the oxidation of propane over diluted Mo 1 -V 0.3 -Te 0.23 -Nb 0.125 -O x are described. The kinetic study allowed determination of the orders of propane disappearance, propene formation, CO x formation, and acids formation. The results show that selective oxidation of propane to propylene over this catalyst follows the Langmuir-Hinshelwood mechanism. Deep oxidation of propane to carbon dioxide is first order with respect to hydrocarbon, and partial order (0.21) with respect to oxygen. The selective oxidation of propane to acrylic acid is half order with respect to hydrocarbon and partial order (0.11) with respect to oxygen, while water does not participate directly in propane transformation. The result also shows that the overall reaction consists of three parallel process channels. One main sequence of consecutive reactions leads to the desired product.

Partial Oxidation of Propane Over Mo1V0.3Te0.23Nb0.12OxCatalyst in a Fluidized Bed Reactor

“…Table 4 worthy indicates that gas phase oxygen concentration has little effects on the acrylic acid selectivity. This agrees with the conclusions of other authors who studied the propane partial oxidation in the fixed bed (Widi et al 2009;Novakova et al 2002).Moreover, table 4 shows that the overall process is only slightly influenced by steam concentration; denoting that water do not participate directly in propane conversion (Zhu et al 2004). …”

“…In this case, in the first step, the hydrocarbon reacts with A c c e p t e d M a n u s c r i p t 14 the lattice oxygen to form products and then the reduced sites of the catalyst are reoxidized by the gas phase oxygen (Mazloom and Alavi 2013). Based on the welldocumented literature (Widi et al 2009;Ramos et al 2000), the reaction order of oxygen in the selective oxidation of propane to oxygenated products was near zero, whereas the oxygen reaction order in the non-selective total oxidation of propane was found to be greater. The experimental data collected in this work in the fluidized bed and fixed bed reactorsalso confirm this observation.…”

Constructing A Rational Kinetic Model of the Selective Propane Oxidation Over A Mixed Metal Oxide Catalyst

“…The Mars-van-Krevelen (MvK) mechanism is widely accepted for selective oxidation reactions over mixed metal oxide catalysts [1,2,36,37]. Further significant inspiration to our mechanistic development was provided by different concepts: (i) the site isolation concept by Grasselli [19][20][21]; (ii) the concept of an ensemble of atoms forming an active site by Schlögl [22]; (iii) the proposed multi-route parallel reaction pathways by Schlögl et al [8] and Barrault et al [3]; and (iv) the change in product distribution upon surface acidity by Barrault et al [3] and Luo et al [46].…”

KINETIC INVESTIGATION OF CARBON DIOXIDE, ACETIC ACID, ACRYLIC ACID FORMATION ON DILUTED AND LEACHED MoVTeNb CATALYST

“…Finally, for the water dependence, water concentration was varied and concentrations of the others were maintained. The effect of reactant concentration was studied at four different temperatures, i.e., 653, 663, 673, and 683 K. Particle size of catalytic material was 212-425m or less [6,9]. (2) where, %vol is concentration of product in % (v/v); total gas flow is the total flow of product stream from the reactor in mLN/min; Mr and d are molecular weight and density of the product; and catalyst weight is the weight of catalyst in gram.…”

“…A number of assumptions on how the MoVTeNb catalyst works suggested [3][4][5] In the previous article, it has been described the reaction kinetics and mechanism of propane partial oxidation to acrylic acid on diluted MoVTeNbOx mixedoxide catalysts using high-throughput system (nanoflow reactor) [6]. This article more focus and deals with the similar reaction oxidation over diluted and leached MoVTeNbOx mixed-oxide catalysts.…”