V2O5 catalyst

V2O5 with promoters is used in a variety of industrial processes, for example the oxidation of ethylene. Recently, catalysts, such as supported M0O3 and 1 wt% 

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Phthalic anhydride will, in the presence of the V2O5 catalyst of Example 9.1, undergo complete oxidation with A772 = — 760kcal/mol. Suppose the complete oxidation is pseudo-first-order in phthalic anhydride concentration and that ln( k//) = 12.300—10,000/T. 

An alternative route to phthalic anhydride is the partial oxidation of naphthalene. The heat of reaction is — 430 kcal/mol. This reaction can be performed using a promoted V2O5 catalyst on silica, much like that considered in Example 9.1. Suppose In(fik) = 31.6800—19,100/T for the naphthalene oxidation reaction and that the subsequent, complete oxidation of phthalic anhydride follows the kinetics of Problem 9.3. Suppose it is desired to use the same reactor as in Example 9.1 but with a,>, = 53g/ m. Determine values for and T aii that maximize the output of phthalic anhydride from naphthalene. 

Influence of reducing power on selective oxidation of H2S over V2O5 catalyst in IGCC system... 

It can be suggested that the lower activity of V2O5 under the influence of water vapor was caused not only by the shift of thermodynamic equilibrium but also by the reduction of V2O5. It was believed that the decrease of the V2O5 reduction property, caused by the decrease of the reducing power, leaded to the deterioration of the activity of V2O5 catalyst in the selective oxidation of H2S under the influence of water vapor. 

The V2O5 catalyst was suitable for the hydrated reactant flows. 

The effect of forced concentration cycling was investigated on the oxidation of CO over industrial V2O5 catalyst. The resulting rate, when time-averaged, exhibited frequency-dependent harmonic behavior, with multiple extrema. Some preliminary interpretation is provided by analogy to an electrical network containing resistance and inductance. 

An experimental gradientless reactor (similar to that in Figure 1.2), which acts as a CSTR operating adiabatically, was used to measure the rate of oxidation of SO2, to S03 with a V2O5 catalyst (Thurier, 1977). The catalyst is present as a fixed bed (200 g) of solid particles within... 

Clarks Third Law could apply to the highly selective V2O5 catalyst for manufacturing MA- Name two other catalysts that might fall under Clarks Third Law. 

C. Zhao and l.E. Wachs, Selective oxidation of propylene over model supported V2O5 catalysts Influence of surface vanadia coverage and oxide support, J. Catal, 257, 181-189 (2008). 

Sulfur and oxygen are burned to SO2, (Fig. 2.4, about 10% SO2 by volume) at 1000°C and then cooled to 420 °C. The SO2 and O2 enter the converter, which contains four different chambers of V2O5 catalyst. About 60-65% SO2 is converted to SO3 in the first layer with a 2-4 sec contact time. It is an exothermic reaction so the gas leaves at 600 °C. It is cooled to 400 °C with a heat exchanger (Fig. 2.5) and enters the second layer of catalyst. 

The V2O5 catalyst has been the catalyst of choice since the 1920s. It is absorbed on an inert silicate support. It is not subject to poisoning and has about a 20-year lifetime. 

Three well known examples of processes employing fluidised-bed operations are the oxidations of naphthalene and xylene to phthalic anhydride using a supported V2O5 catalyst and ammoxidation of propylene utilising a mixed oxide composition containing bismuth molybdate. Typically, this latter reaction is executed by passing a mixture of ammonia, air and propylene to a fluidised bed operating at about 0.2 MPa pressure, 400—500°C and a few seconds contact time between gas and fluidised catalyst peirticles. 

A series of 1% V2O5 catalysts was prepared by non aqueous impregnation of vanadium tri- isopropoxide oxide (final calcination in oxygen at 450/500 C) in order to investigate the influence of different oxide supports... 

Previous studies indicate that O ion is the oxidizing agent in the pai tial oxidation of ethane on supported M0O3 and V2O5 catalysts, and this is the surface species which... 

We first discuss EM studies of M0O3 and V2O5 catalysts. M0O3 is used along with other catalysts in the selective catalyzation of hydrocarbons. The wealth of novel information revealed by EM studies is key to understanding the... 

Figure 3.9. A structural model of the V2O5 catalyst (a) square pyramids and the idealized octahedral model in the (001) (b) (010) (c) and (100) (d) projections.

Conversion I First pass conversion of SO2 to SO3 in three beds of V2O5 catalyst and intermediate heat removal in uaste heat boiler, economiser and heat exchangers. 

The ammoxidation of benzene is described in some papers and patents [124, 128, 131, 132]. Whilst benzene has been reported to remain unconverted in the presence of ammonia and oxygen with a V2O5 catalyst [124], it was efficiently transformed to nitriles with catalysts based on mixed molybdates [128]. 

Although platinum catalysts once were used in the manufactme of sulfuric acid, the only catalysts presently in use employ supported vanadia. ° For om problem we shall use a catalyst studied by Eklimd, whose work was echoed extensively by Donovan" in his description of the kinetics of SO, oxidation. The catalyst studied by Eklimd was a Reymersholm V2O5 catalyst deposited on a pumice carrier. The cylindrical pellets had a diameter of 8 mm and a length of 8 mm, with a bulk density of 33.8 Ib/ft. Between 818 and 1029°F, the rate law for SO, oxidation over this particular catalyst was... 

V2O5 catalysts are structure-sensitive for various reactions. The V=0 group located in the (010) plane plays an essential role in many reactions. Another aspect of these catalysts is the nature of the active site that leads to the SCR reaction or the oxidation of ammonia when ammonia is used as reductant. 

Kotter et al. [79] prepared V and Ti-containing catalysts by dissolving appropriate amounts of ammonium vanadate in a titanium oxychloride solution followed by hydrolysis and evaporation. The 20 wt.-% V2O5 catalyst thus formed showed a decrease in BET specific surface area from 85 to 20 m g after heating the sample at 713 K for 100 h. 

C to form sulfur dioxide, which then reacts with oxygen to form sulfur trioxide over a V2O5 catalyst at 500°C. Because sulfur trioxide forms a corrosive acid with water, it is absorbed in 98% concentrated sulfuric acid to give a dense, oily liquid called oleum, H2S2O7. 

A key feature of the chamber process is that nitrous acid in the vapor state is the oxidant used to convert sulfurous acid to sulfuric acid (Eq. 9.32). Unlike platinum, or V2O5 catalysts of the... 

When more than one reaction occurs the calculation procedures are similar to those illustrated in Example 13-6. A difference equation is written for each component, and these equations are solved simultaneously with the difference equation for the conservation of energy. Froment has used one- and two-dimensional models to predict conversion and temperatures in a fixed-bed reactor for the oxidation of o-xylene to phthalic anhydride, CO, and COj, with a V2O5 catalyst. The reaction scheme is... 

Dehydrogenation of alkanes with oxidized diamond supported Cr203 and V2O5 catalysts. 

We applied this technique to the preparation of VaOs/TiOz catalysts and here report the effect of organosilane on the thermal stability of a TiOa support with a large surface area, the adsorption properties of metavanadate anion (VO3 ), and the SCR activities of supported V2O5 catalysts prepared from VOj -adsorbing TiOa supports. 

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