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Fait, Martin; Kubias, B.; Eberle, Hans-Jürgen; Estenfelder, M.; Steinike, U.; Schneider, Mat­thias

doi:10.1023/a:1019042311089

Cited by 15 publications

(11 citation statements)

References 8 publications

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“…The surface area of milled precursor (9.8 m 2 ⋅g -1 ) is higher than unmilled precursor (6.4 m 2 ⋅g -1 ), indicating ball milling process increased surface area as reported by previous literatures [7][8][9]. This result also in agreement with the results obtained from XRD and SEM, which indicated that crystallite size of the catalyst was reduced.…”

Section: Bet Surface Area Measurementssupporting

confidence: 91%

“…Zazhigalov et al [8] reported that mechanochemical treatment could cause repeated fracture of the solids, reducing its particle size and corresponding increase of the specific area. This observation was agreed by Fait et al, [9] which also reported that a decreased particle size and increased of microstrain in the VOHPO 4 • ½H 2 O precursor would improved catalytic properties of the V-P-O catalysts. Ji et al [10] have prepared V-P-O catalysts doped by combined components (Zn+Zr+Mo, Zr+Zn and Zr+Mo) through impregnation and then followed by ball milling process.…”

Section: Introductionsupporting

confidence: 87%

“…These patterns show that the intensities of the peaks after milled are drastically decreased and FWHM values are increased. This indicates that particle size is reduced whereas the microstrain is increased [9].…”

Section: X-ray Diffraction (Xrd)mentioning

confidence: 94%

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Characterization of Mn-Doped Vanadium Phosphorus Oxide (VPO) Catalyst: Effect of Ball Milling

Taufiq‐Yap

Goh

2016

Eur Chem Tech J

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The effect of ball milling on the structure and surface reactivity of the Mn-doped vanadium phosphorus oxide (V–P–O) catalyst is discussed. Mn-doped VOHPO4·½H2O precursor was prepared via organic method. The precursor was ball milled in isopropyl alcohol using agate balls for 60 min at 800 rpm. XRD, BET surface area measurements, SEM, O2-TPD, H2-TPR and TPD of NH3 were used to characterize properties of the final catalysts. The results revealed that mechanical treatment of Mn-doped V–P–O catalyst increased surface area as well as reduced particle size of the material. Furthermore, process also increased exposure of (001) crystallographic plane of VOHPO4·½H2O precursor. The secondary structure of the milled material is also lost. The total amount of oxygen desorbed (from O2-TPD) and removed (by H2-TPR) from milled material is higher compared to the unmilled one. The surface acidity of the catalyst was also increased after milling process, as evidenced by lower desorption temperature and higher total amount of the ammonia desorbed.

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Section: Bet Surface Area Measurementssupporting

confidence: 91%

Section: Introductionsupporting

confidence: 87%

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Characterization of Mn-Doped Vanadium Phosphorus Oxide (VPO) Catalyst: Effect of Ball Milling

Taufiq‐Yap

Goh

2016

Eur Chem Tech J

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“…Ball-milling of the precursor is carried out with the aim of increasing the surface area by reducing particle size; this results in higher catalyst activity [67]. However, also lattice imperfections are introduced, as a consequence of the high energy used for milling; these defects are transferred to the VPP during transformation of the precursor, and finally affect the catalytic performance [68]. This leads to an improvement of the activity and selectivity.…”

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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“…Among numerous compounds formed in VPO system, vanadyl pyrophosphate, (VO) 2 P 2 O 7 is known to be the most efficient catalyst for partial oxidation of n-butane to maleic anhydride and this phase is usually obtained by activating the precursor, VOHPO 4 ÁH 2 O in an n-butane/air gas mixture at about 673 K for an extended time period [3]. It has been shown that the mechanochemical treatment of VOHPO 4 ÁH 2 O could impair the structure and morphology of the final VPO catalysts and, accordingly the catalytic properties [4]. One of the factors affected the effectiveness of ball milling is the media in which the miling takes place [5].…”

Section: Introductionmentioning

confidence: 99%

Influence of Milling Media on the Physicochemicals and Catalytic Properties of Mechanochemical Treated Vanadium Phosphate Catalysts

et al. 2010

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VOHPO 4 Á0.5H 2 O synthesized via the alcohol reduction of VOPO 4 Á2H 2 O was mechanochemical treated for 30 min in three different media, i.e. cyclohexane, ethanol and air. XRD results revealed that their structure became less crystalline compared to the unmilled material. SEM showed that the particles for the milled materials become smaller and unique features were observed in the different type of media used. The reactivity of the oxygen species linked to V 5? and V 4? were also affected by the milling process. The selectivity to maleic anhydride from n-butane oxidation were observed to increase in line with the increase in the oxygen species associated with V 5? and the presence of isolated V 5? phase. A correlation was observed between the crystallite size of the pyrophosphate phase at (020) plane with the maleic anhydride selectivity.

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Cited by 15 publications

References 8 publications

Characterization of Mn-Doped Vanadium Phosphorus Oxide (VPO) Catalyst: Effect of Ball Milling

Characterization of Mn-Doped Vanadium Phosphorus Oxide (VPO) Catalyst: Effect of Ball Milling

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

Influence of Milling Media on the Physicochemicals and Catalytic Properties of Mechanochemical Treated Vanadium Phosphate Catalysts

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