Vanadium Phosphorus Oxide Catalyst Modified by Niobium Doping for Mild Oxidation of n-Butane to Maleic Anhydride

Farias, Andréa M. Duarte de; Gonzalez, Wilma de Araújo; Oliveira, P.G. Pries de; Eon, Jean‐Guillaume; Herrmann, Jean-Marie; Aouine, M.; Loridant, S.; Volta, J.C.

doi:10.1006/jcat.2002.3562

Cited by 51 publications

(29 citation statements)

References 31 publications

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“…Recently, some of us discovered that doping a VPO catalyst with niobium (Nb/V = 0.01) induced defects at the periphery of (VO) 2 P 2 O 7 crystals while Nb was simultaneously concentrating at the periphery. This fact was associated with an increase of the n-butane conversion for mild oxidation to maleic anhydride [4]. On the other hand, NbMCM-41 materials appeared to be active in both ODH (oxidative dehydrogenation) of propane [5] and in the liquid-phase oxidation of cyclohexene [6].…”

Section: Introductionmentioning

confidence: 84%

The role of niobium in the gas- and liquid-phase oxidation on metallosilicate MCM-41-type materials

Kilos

Aouine

Nowak

et al. 2004

Journal of Catalysis

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Section: Introductionmentioning

confidence: 84%

The role of niobium in the gas- and liquid-phase oxidation on metallosilicate MCM-41-type materials

Kilos

Aouine

Nowak

et al. 2004

Journal of Catalysis

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“…28 Shortly, V 2 O 5 was suspended into isobutanol containing H 3 PO 4 obtaining a formal P/V ratio of 1.15. The dopant Nb 5+ was included by solving niobium(V) ethoxide into the isobutanol/V 2 O 5 suspension with a Nb/V ratio of 0.2.…”

Section: Methodsmentioning

confidence: 99%

“…Furthermore, it was reported that Nb 5+ can act as an n-type dopant upon increasing the activity of the catalyst. 28 As already mentioned in the introductory remarks the selective oxidation of butane to maleic anhydride demands the transfer of 14 electrons and 3 oxygen atoms in a single pass. As a consequence it seems reasonable that a certain electrical conductivity is desirable for a high product yield.…”

Section: 4mentioning

confidence: 97%

The microwave cavity perturbation technique for contact-free and in situ electrical conductivity measurements in catalysis and materials science

Eichelbaum

Stößer

Karpov

et al. 2012

Phys. Chem. Chem. Phys.

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We have developed a noncontact method to probe the electrical conductivity and complex permittivity of single and polycrystalline samples in a flow-through reactor in the temperature range of 20-500 1C and in various gas atmospheres. The method is based on the microwave cavity perturbation technique and allows the simultaneous measurement of microwave conductivity, permittivity and of the catalytic performance of heterogeneous catalysts without any need for contacting the sample with electrodes. The sensitivity of the method towards changes in bulk properties was proven by the investigation of characteristic first-order phase transitions of the ionic conductor rubidium nitrate in the temperature range between 20 and 320 1C, and by studying the temperature dependence of the complex permittivity and conductivity of a niobium(V)-doped vanadium-phosphorous-oxide catalyst for the selective oxidation of n-butane to maleic anhydride. Simultaneously, the catalytic performance was probed by on line GC analysis of evolving product gases making the technique a real in situ method enabling the noninvasive investigation of electronic structure-function relationships.

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“…This is the case of Co and Fe [33][34][35][36][37][38][39][40], and of Bi [41]. A new type of promoter for VPO, mentioned in an early ICI patent [42] and later on claimed by Matsuura et al [43], is Nb [44][45][46]. This element promotes the catalyst activity through generation of surface defects, to which Lewis acid sites are likely associated, that participate in the activation of the alkane.…”

Section: The Modification Of Vpp Properties By the Addition Of Dopantsmentioning

confidence: 97%

“…The re-oxidation rate is increased [48,49] Ga, Ga/V 0.10 C 22 fi 73% and S 55 fi 51% Increase of surface area + increase of intrinsic activity (electronic effect) [50] Nb, 0.25 wt% C 20 fi 17% and S 35 fi 53% Increase of surface acidity promotes desorption of MA [44] Nb, Nb/V 0.01 C 58 fi 75% and S 70 fi 70% Nb concentrates at the surface, where defects are generated. Nb acts a n-type dopant; development of a more oxidised surface [45] a C ¼ conversion; Y ¼ yield; S ¼ selectivity for the undoped fi doped catalysts, at fixed reaction conditions. importance of the reactant size is also demonstrated by the much lower amount of alcohol that is retained when only isobutanol (a branched-chain compound) is used (sample 1 in table 2).…”

Section: Other Options For Modifications Of Vpp Chemical-physical Promentioning

confidence: 99%

VPO catalyst for n-butane oxidation to maleic anhydride: A goal achieved, or a still open challenge?

et al. 2006

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A Partner of Concorde CA and of Idecat NoE, 6FP of the EU) b Lonza SpA, via E. Fermi 51, 24020 Scanzorosciate (BG), ItalyThis review describes recent findings in the oxidation of n-butane to maleic anhydride. The process is commercial since the 80's, but yet the yield is far from being optimised. Therefore, it represents an emblematic example of how several scientific disciplines, from solid-state science to reactor technology, can contribute to the improvement of the process performance.KEY WORDS: Vanadyl pyrophosphate; n-butane; selective oxidation; maleic anhydride 1. The oxidation of n-butane catalysed by VPO: How to improve process performance?The activation of light alkanes by high-temperature contact with a redox catalyst represents one way to transform these hydrocarbons to valuable chemicals (a few reviews and books dealing with this topic, published after 1998, are refs [1-18]). The most successful example is the oxidation of n-butane to maleic anhydride (MA), catalysed by a V/P/O-based catalyst (VPO), which starting from the 80's has been replacing in part the commercial synthesis from benzene. This reaction, and the unique chemical-physical properties of the vanadyl pyrophosphate (VO) 2 P 2 O 7 (VPP), the active and selective phase for this reaction, are amongst the most studied topics in catalysis during the latest decades, initially with the aim of understanding which catalyst peculiarities make this complex transformation possible, and later on with the aim of improving the process performance.MA finds its major use in the production of unsaturated polyesters and of butanediol. The yearly world consumption exceeds 1.3 · 10 6 metric tons [19]. Approximately 70% is produced by n-butane oxidation, the remaining still being obtained from benzene. There are several reactor technologies available, including fixed-bed (Scientific Design, Huntsman, BASF, Pantochim), fluidised-bed (Lonza, BP, Mitsubishi), and transported-bed (DuPont). Best process performances reported in patent literature range from 53 to 65% molar yield to MA [20][21][22][23][24][25], with a conversion of the hydrocarbon not higher than 85-86%. An excellent result of more than 70% yield is reported [26], which however refers to a recycle process. In lab reactors best yields reported are lower than 50%.The best performance for a fixed-bed reactor does not exceed 65% per-pass yield, while that in a fluidised-bed is typically somewhat lower; in fact, back-mixing phenomena are responsible for the consecutive combustion of MA. Moreover, with fluidised-bed operation n-butane-richer conditions can be used (up to 5 molar % in feed); under the latter conditions, a worsening of selectivity is expected, which however is compensated by a considerable improvement in MA productivity. In the fluidised-bed process developed by Lonza and Lummus (shown in figure 1), the loss of selectivity is also compensated by the higher amount of high-pressure steam produced, due to the more efficient removal of the reaction heat and to the more CO x produced.The maximu...

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Vanadium Phosphorus Oxide Catalyst Modified by Niobium Doping for Mild Oxidation of n-Butane to Maleic Anhydride

Cited by 51 publications

References 31 publications

The role of niobium in the gas- and liquid-phase oxidation on metallosilicate MCM-41-type materials

The role of niobium in the gas- and liquid-phase oxidation on metallosilicate MCM-41-type materials

The microwave cavity perturbation technique for contact-free and in situ electrical conductivity measurements in catalysis and materials science

VPO catalyst for n-butane oxidation to maleic anhydride: A goal achieved, or a still open challenge?

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