research article revisiting oxidative dehydrogenation of...

Research ArticleRevisiting Oxidative Dehydrogenation of Ethane byW Doping into MoVMn Mixed Oxides at Low Temperature

Mohammed H Al-Hazmi1 Taiwo Odedairo12 Adel S Al-Dossari1 and YongMan Choi1

1SABIC Technology Center Riyadh 11551 Saudi Arabia2School of Chemical Engineering The University of Queensland St Lucia Brisbane QLD 4072 Australia

Correspondence should be addressed to Mohammed H Al-Hazmi hazmimhsabiccom and YongMan Choi choiysabiccom

Received 9 November 2014 Revised 17 December 2014 Accepted 31 December 2014

Academic Editor Jinlong Gong

Copyright copy 2015 Mohammed H Al-Hazmi et al This is an open access article distributed under the Creative CommonsAttribution License which permits unrestricted use distribution and reproduction in any medium provided the original work isproperly cited

The catalytic performance ofMoVMnWmixed oxides was investigated in the oxidative dehydrogenation of ethane at three differentreaction temperatures (235 255 and 275∘C) using oxygen as an oxidantThe catalysts were characterized by using X-ray diffractiontemperature-programmed reduction and scanning electron microscopyTheMoVMnWmixed oxide catalyst showed the 70ndash90of ethylene selectivity at the reaction temperatures However a significant decrease in the selectivity of ethylene was observed byincreasing the reaction temperature from 235∘C to 275∘C

1 Introduction

Ethylene (C2H4) is an important building block used in the

petrochemical industry [1] Its primary production methodis the energy-intensive steam cracking process [2] which isusually carried out at 119879 gt 800∘C [3] Over 100 million metrictons of ethylene is produced annually by means of the steamcracking of long carbon-chain hydrocarbons In additionto the high energy cost unavoidable side reactions andthe deactivation of catalysts by carbon deposition are othertechnical shortcomings of the process Increasing attentionhas been directed towards the oxidative dehydrogenation(ODH) of alkanes because of its potential benefit of usingabundant and inexpensive raw materials [4ndash6] The ODH oflight alkanes offers a potentially attractive route to alkenessince the reaction is exothermic [2] and avoids the ther-modynamic constraints of nonoxidative routes by formingby-product water [7] However a low yield and selectivityof olefins still retard the industrial application of the ODHTo date about a 20 yield of ethylene was reported inthe literature and for industrial applications it requires theethylene productivity of above 1 kgC

2H4

kgcatminus1 hminus1 [8] The

ODH of ethane to ethylene has received less attention thanthe nonoxidative cracking [9] However ethane is the second-largest component of natural gas and the primary product

of the methane conversion by oxidative coupling Thus alarge number of catalysts have been investigated for theODH of ethane and propane for example using Mo-V basedcatalysts [10ndash13] It was reported that a V based catalyst isone of the most active and selective single metal catalystsin the ODH [14 15] while V [10 16ndash18] Mo [12 13 19ndash21] Pt [22ndash25] based catalysts and MoV mixed oxides [26ndash28] are the most widely studied transition-metal catalystsfor the ODH of ethane Furthermore a more complicatedmaterial (ie Mo

1V025

Nb012

Pd00005

Ox [29ndash31]) with twodifferent catalytic centers such as the ODH of ethane and theheterogeneous Wacker oxidation of ethylene to acetic acidwas reported The catalytic activity of MoV based catalystssupported on TiO

2and Al

2O3was investigated in the ODH

of both ethane and propane [32] Recently the catalyticproperties of the acidic and basic forms of Ni- Cu- and Fe-loaded Y zeolites were investigated in the ODH of ethane toethylene [33] As discussed above although numerous studieson the ODH of ethane using MoV based mixed oxides werereported [29 31 32 34 35] to the best of our knowledge littlestudies usingW doping into MoVmixed oxide catalysts havebeen reported in the literature [35 36] demonstrating theethane conversion is the best using a 63mol W doping toMoVMnmixed oxide catalysts In this study to obtain amoresystematic optimal condition of MoVMnW based catalysts

Hindawi Publishing CorporationAdvances in Physical ChemistryVolume 2015 Article ID 102583 9 pageshttpdxdoiorg1011552015102583

2 Advances in Physical Chemistry

for the ODH of ethane we investigated the effect of variousreaction conditions (ie contact time reaction temperatureand conversion) on the selectivities of ethylene acetic acidand COx

2 Experimental

21 Catalyst Preparation Asmentioned 63mol ofW dop-ing toMoVMnmixed oxide catalysts showed the best conver-sion of ethane by the ODH [35] Based on the previous studywe applied three materials of MoV

04Mn018

W0Ox (W

0)

MoV04Mn018

W0063

Ox (W006

) and MoV04Mn018

W014

Ox(W014

) We considered W0and W

014as the extreme cases

without W and the highest doping respectively andW006

asthe optimal one in terms of the ethane conversion from theODH The synthesis method is described in detail elsewhere[36] Briefly ammoniummetavanadate (FlukaChemical) wasadded to deionized water and heated to 85∘C with a constantstirring A yellow colored solution was obtained Oxalic acid(Riedel-de Haen Chemicals) was added with water to thesolution with constant stirring while the required amountof ammonium tungstate (BDH Chemicals) and manganeseacetate (Riedel-de Haen Chemicals resp) was slowly addedto themixtureThen ammoniumheptamolybdate (Riedel-deHaen Chemicals) was added to the solution Precipitates weredried in an oven at 120∘C and calcined at 350∘C for 4 hoursThe calcined catalysts were screened into uniform particles ofa 4060mesh

22 Characterization of Catalysts The samples were char-acterized using several characterization tools including X-ray diffraction (XRD) It was recorded on a Mac ScienceMX18XHF-SRA powder diffractometer with monochroma-tized Cu K120572 radiation (120582 = 0154 nm) at 40 kV and 30mAA Micromeritics AutoChem II 2920 with a thermal con-ductivity detector (TCD) was used for the H

2temperature-

programmed reduction (TPR) analysis to study the reductionproperties of the samples 15ndash20mg of the catalyst sampleswas heated from 40∘C to 1000∘C at a heating rate of 10∘Cminin 10 H

2in Ar Before the H

2-TPR analysis the samples

were heated for 60min in Ar flow at 100∘C The profile ofconsumed H

2was recorded by the TCD Scanning electron

microscopy (SEM) images were recorded using a JEOL JSM-5500LV Surface area calculations were carried out usingThe Brunauer-Emmett-Teller (BET) method Adsorptionisotherms were measured in Quantachrome AUTO-SORB-1at minus196∘C

23 Reaction Apparatus and Procedures Catalytic experi-ments were carried out in a fixed-bed reactor (ID = 078 cm)with the contact times of 008 012 016 024 032 049and 065 sec The contact time was changed by varying theweight of the catalyst in the range of 50ndash400mg and at atotal flow of 30mLmin All experiments were carried out at235 255 and 275∘C and at 200 psi The gas feed compositionused in this study was fixed at 15 vol ethane in 85 vol airTo avoid any mass resistance problem of feed the preparedpowder was pressed to pellets then crushed and sieved to

(a)

6 6 123 3 3 42 2 2 5 2 77

(b)

(c)

10 20 30 40 50 60

Inte

nsity

(au

)

2120579 (deg)

Figure 1 XRD patterns of (a) W0

(b) W006

and (c) W014

calcinedat 400∘C The numbers (1 2 3 4 5 6 and 7) on the top 119909-axiscorrespond toWO

3

orWO4

MoO3

Mo suboxide such asMo8

O23

orMo9

O26

(MxMo1minusx)5O14 (M=V orMn orW)W

3

OV095

Mo097

O5

and Mn

2

O3

respectively

200 400 600 800 1000

Temperature (∘C)

H2

cons

umpt

ion

(au

)

677∘C

769∘C

772∘C

(a)

(b)

(c)

Figure 2 H2

-TPR profiles of (a) W0

(b) W006

and (c) W014

cata-lysts The dashed lines are the reduction peaks

40ndash60mesh particles Reactants and products were analyzedusing an online gas chromatograph equipped with a doubledetector (ie thermal conductivity detector (TCD) and flameionization detector (FID)) and two columns of HayeSep D80100mesh and LAC446 We confirmed the reproducibilityof the experiment results within the uncertainty of plusmn2Then we obtained the conversion (119883ethane) selectivity toproduct 119894 (119878

119894) and yield to product 119894 (119884

119894)

3 Results and Discussion

31 Characterization of Samples Crystalline phases of thethree catalysts were characterized by XRD Figure 1 showsXRD patterns of W

0 W006

and W014

calcined at 400∘CMo suboxides (ie Mo

8O23

(or Mo9O26) MoO

3 and

(VxMo1minusx)5O14) were noticed as the major phases (Figure 1)

Advances in Physical Chemistry 3

(a)

(b)

(c)

Figure 3 SEM images of (a) W0

(b) W006

and (c) W014

Also (MxMo1minusx)5O14 (M = V Mn or W) was observed

as one of the major phases The reason that most lines ofMoO3are shifted compared to the standard pattern (JCPDS

76-1003) may be due to a modification by vanadium (ieorthorhombic 120572-VxMo

1minusxO3minus05x) or the formation of oxygenvacancies in MoO

3minusx Also triclinic V095

Mo097

O5(JCPDS

77-0649) whose XRD patterns are close to that proposed forVMo3O11

[37] was observed The BET surface areas of W0

W006

and W014

are 156m2g 139 and 153 respectivelyindicating that theW doping shows an insignificant effort onthe textural properties of the materials

TPR in H2was performed to examine reduction charac-

teristics of the mixed oxide catalysts as displayed in Figure 2There are two reduction peaks observed for W

0at 587∘C

and 677∘C which correspond to the reduction of isolated V5+species in the bulk structure of the catalyst [38 39] andMo6+species [40] respectively In addition the observed shoulderat a temperature around 470∘C is assumed to be H

2uptake

associated with the reduction of MnO2to Mn

2O3[41] The

position of the peak at 677∘C is shifted to higher temperaturesof 769∘C (W

006) and 772∘C (W

014) and becomes broadened

without a significant change in peak intensities Solsona andcoworkers [42] reported a similar shift whenWwas added to

NiO and proposed that the shift was related to an interactionbetween NiO and tungsten oxide nanoparticles As shownin the peaks of W

006 the H

2consumption at 470∘C and

587∘Cwas enhanced by the addition ofW loading (W0versus

W006

) We observed that the reduction occurred slightly athigher temperatures by adding more W into the MoVMnbased catalysts (W

006versus W

014)

Figure 3 shows typical SEM images of W0 W006

andW014

doped catalysts displaying that all samples have irreg-ular shaped particles The SEM image of W

0without W

ascertains a rough surface with variable shapes and sizes anda few regions show a stack of fine crystallites (Figure 3(a))Similarly W

006has a rough surface with variable shapes and

sizes but without a stack of fine crystallites (Figure 3(b))TheSEM images of W

014determine a stack of fine crystallites

leading to a flower-like morphology (Figure 3(c))

32 Catalytic Performance from the ODH of Ethane Figure 4shows the effect of W loading on the ethane conversionand product selectivity from the ODH of ethane at 275∘Cand at a reaction time of 065 sec Ethylene is observed asthe major product from the ODH of ethane while aceticacid CO and CO

2are also detected The highest ethane


25

20

15

10

5

Xet

hane

()

0 2 4 6 8 10 12 14

60

30

0

C2H4

CH3COOH

CO

CO2

Si

()

W ()

Figure 4 Influence ofW loading intoMoVMnmixed oxide samplesat 275∘C and at a reaction time of 065 sec

conversion (sim210) is observed from the MoVMn samplewith W = 0063 The increase in the amount of W over theMoVMn sample leads to a reduction in the conversion ofethane Similarly the addition of W results in an increasein the selectivity of ethylene with a maximum selectivity (sim74) achieved at W = 0063 The lowest selectivity of aceticacid (sim12) is detected at W = 014 The ODH experimentof ethane was carried out at two more temperatures of 235and 255∘C using the W

006catalyst with the contact times

of 008 012 016 024 032 049 and 065 sec (Figure 5)As shown in Figure 5 ethane conversions of approximately70 113 and 210 are achieved at 235 255 and 275∘Crespectively at a contact time of 065 sec The conversion ofethane is improved as the contact time increases In this studythe maximum ethane conversion was obtained at 275∘CThe product distribution from the ODH of ethane on theW006

catalyst at 235 255 and 275∘C is presented in Figure 6At all temperatures studied ethylene is the major productwhile acetic acid and carbon oxides are also observed (iesim35 and sim17 resp at 275∘C) Figure 7 presents theinfluence of reaction temperatures and contact times forthe selectivities of ethylene acetic acid and carbon oxides(CO and CO

2) The selectivities of ethylene decrease by

the increase of contact times at all temperatures studiedThe highest selectivity of ethylene is observed at a reactiontemperature of 235∘C Increasing the reaction temperaturefrom 235∘C to 275∘C leads to a reduction in the selectivityof ethylene while an enhancement of selectivities of aceticacid CO and CO

2are observed (Figure 7(b) and Table 1)

Table 1 compiles theoretical selectivities of ethylene and COxat each reaction temperature The trend of the reactionproducts over the W

006catalyst indicates that ethylene is a

key source of acetic acid and carbon oxides Furthermorethe reduction of the selectivity of ethylene along with thecorresponding increase of the by-products (acetic acid andcarbon oxides) clearly manifests that acetic acid and carbonoxides are the secondary products from the consecutiveoxidation of ethylene The effect of ethane conversion on theselectivities of ethylene acetic acid CO and CO

2at 235 255

and 275∘C over W006

is plotted in Figure 8 demonstrating

25

20

15

10

5

0

00 01 02 03 04 05 06 07

Time (s)

235∘C

255∘C

275∘C

Xet

hane

()

Figure 5 Variation of ethane conversion against contact timeachieved over the W

006

catalyst at 235 (◼) 255 (e) and 275∘C (998771)The solid curves are predicted results based on the kinetic modeling

Reaction temperature (∘C)235

18

16

14

12

10

8

6

4

2

0255 275

C2H4

CH3COOHCOx

Yi

()

Figure 6 Yield from the OHD of ethane over the W006

catalyst(reaction temperatures = 235 255 and 275∘C and a contact time =065 sec)

a strong dependence of ethane conversion and selectivity Itis observed that the selectivity decreases as ethane conversionincreases Also the selectivity of by-products (ie acetic acidCO2 and CO) shows a linear relation with the conversion of

ethane As the reaction temperature increases the selectivityof ethylene decreases Our experimental data suggest thatethylene undergoes substantial further oxidation and theODH of ethane can be described by the parallel consecutivescheme [43]

33 Kinetic Studies A kinetic model was developed tounderstand the ODH of ethane on MoVMnW mixed oxidecatalysts A generally accepted scheme for the ODHof ethane


00 01 02 03 04 05 06 07

0

5

10

15

20

COCO2

CH3COOH

Si

()

Time (s)

(a)

00 01 02 03 04 05 06 07

Time (s)

95

90

85

80

75

70

Set

hyle

ne(

)

235∘C

255∘C

275∘C

(b)

Figure 7 Contact-time dependence of selectivities for (a) CH3

COOH CO and CO2

at 275∘C and (b) ethylene at 235 255 and 275∘C in theODH of ethane over the W

006

catalyst

Table 1 Theoretical selectivitiesa of ethylene and CO119909

Reaction temperature (∘C) 119878ethylene () 119878CO119909 ()235 905 14255 859 20275 840 19aThey were obtained by linear regression analyses at their zero conversion

is shown in Scheme 1 [3 33 44] The kinetic parameters 1198960119894

119864119894 and 120572 for the ODH of ethane over the W

006catalyst

were obtained using a nonlinear regression To develop akineticmodel for theODHof ethane three assumptions weremade (1) the ODH is isothermal (2) a catalyst deactivationis a function of time-on-stream (TOS) and (3) a singledeactivation function is defined for all reactions and athermal conversion is neglected Based on the assumptionsrates of the disappearance of ethane (119903C

2H6

) and the formationof ethylene (119903C

2H4

) acetic acid (119903CH3COOH) and carbon oxides

(119903CO119909

) respectively are described as follows

minus119889119862C

2H6

119889119905120591

= (1198961119862C2H6

119862O2

+ 1198962119862C2H6

119862O2

) sdot 120593 (1)

119889119862C2H4

119889119905120591

= (1198961119862C2H6

119862O2

minus 1198963119862C2H4

119862O2

minus 1198964119862C2H4

119862O2

) sdot 120593

(2)

119889119862CH3COOH

119889119905120591

= (1198964119862C2H4

119862O2

) sdot 120593 (3)

119889119862CO119909

119889119905120591

= (1198962119862C2H6

119862O2

+ 1198963119862C2H4

119862O2

) sdot 120593 (4)

C2H6 C2H4 + H2O+O2+O2

CH3COOH

COx

k1

k2 k3

k4

Scheme 1 Schematic of catalytic reactions of the ODH of ethane

where119862119894is a concentration of species 119894 in the units ofmolm3

119905120591is a reaction in the unit of time (ie at inlet of the catalyst

bed 119905120591= 0 and at the outlet of the catalyst bed 119905

120591= 120591)

119896119894is an apparent rate constant for the 119894th reaction in the

unit of sminus1 and 120593 is the apparent deactivation function Themeasurable variables from our chromatographic analysis arethe weight fraction of the species 119910

119909 in the system By

definition themolar concentration119862119909 of every species in the

system can be related to its mass fraction 119910119909by the following

relation

119862119909=

119910119909119865TM

120592119900MW119909

(5)

where 119865TM is the total mass flow rate (kgmin) MW119909is the

molecular weight of species 119909 in the system and 120592119900is the total

volumetric flow rate (m3min)Regarding catalyst deactivation as deactivation functions

can be expressed in terms of the catalyst time-on-stream(120593 = exp(minus120572119905)) deactivation can also be related to theprogress of the reaction [45] where120572 is a catalyst deactivationconstantThe deactivation function based on time-on-streamwas initially suggested by Voorhies [46]


0 5 10 15 20

0

5

10

15

20Si

()

Xethane ()

COCO2

CH3COOH

(a)

70

75

80

85

90

95

Set

hyle

ne(

)

235∘C

255∘C

275∘C

0 5 10 15 20

Xethane ()

(b)

Figure 8 Dependence of ethane conversion versus selectivity for (a) CH3

COOH CO and CO2

at 275∘C and (b) ethylene at 235 255 and275∘C in the ODH of ethane over the W

006

catalyst The data sets are from different contact times

Substituting (5) into (1)ndash(4) we have the following firstorder differential equations which are in terms of weightfractions of the species

minus119889119910C2H6

119889119905120591

= 1198691(1198961119910C2H6

119910O2

+ 1198962119910C2H6

119910O2

) exp (minus120572119905) (6)

119889119910C2H4

119889119905120591

= (11986921198961119910C2H6

119910O2

minus 11986911198963119910C2H4

119910O2

minus 11986911198964119910C2H4

119910O2

)

sdot exp (minus120572119905)(7)

119889119910CH3COOH

119889119905120591

= (11986931198964119910C2H4

119910O2

) exp (minus120572119905) (8)

119889119910CO119909

119889119905120591

= (11986941198962119910C2H6

119910O2

+ 11986951198963119910C2H4

119910O2

) exp (minus120572119905) (9)

where 1198691 1198692 1198693 1198694 and 119869

5 respectively are given by 119869

1=

119865TM120592119900MWO2

1198692= 119865TMMWC

2H4

120592119900MWC

2H6

MWO2

1198693=

119865TMMWCH3COOH120592119900MWC

2H4

MWO2

1198694

= 119865TMMWCO119909

120592119900MWC

2H6

MWO2

and 1198695= 119865TMMWCO

119909

120592119900MWC

2H4

MWO2

The temperature dependence of the rate constants was repre-sented with the centered temperature form of the Arrheniusequation that is

119896119894= 119896119900119894exp [

minus119864119894

119877(1

119879minus

1

119879119900

)] (10)

where 119879119900is an average temperature introduced to reduce

parameter interaction in the unit of K [47] 119896119900119894is the rate

constant for reaction 119894 at 119879119900(sminus1) and 119864

119894is the activation

energy for reaction 119894 (kJmol) Since the experimental runswere done at 235 255 and 275∘C To was calculated to be255∘C The values of the model parameters along with their

Table 2 Estimated kinetic parameters for theODHof ethane on theW006 catalyst

Parameters Values1198961

1198962

1198963

1198964

120572

119864119894

(kJmol) 605 1396 924 241 00395 CL 80 157 139 22119896119900119894

times 104 (sminus1) 0670 0045 0310 0810

95 CL times 104 0005 0016 0012 0053

corresponding 95 confidence limits (CLs) are shown inTable 2 while the resulting cross-correlationmatrices are alsogiven in Table 3 The cross-correlation matrices give goodresults as indicated by a low correlation between most of theparameters with only a few exceptions From the results ofthe kinetic parameters presented in Table 2 it was observedthat the catalyst deactivation was found to be small 120572 =003 indicating a low coke formation As mentioned theODH of ethane can occur via the reaction network as shownin Scheme 1 in which ethane reacts with oxygen to formethylene with a rate constant 119896

1 or carbon oxides (COx) with

a rate constant 1198962 Ethylene then undergoes a subsequent

oxidation to COx and CH3COOH with rate constants 1198963and

1198964 respectively Rate constants 119896

1and 119896

2can be used to

determine the ODH of ethane activities while the ratios ofrate constants (ie 119896

11198962and 119896

11198963) are used to determine

the ethylene selectivity High ethylene yields at a reasonablecontact time apparently require high values of 119896

1and low val-

ues of 11989621198961and 11989631198961The kinetic parameters (119896

1 1198962 1198963 and

1198964) summarized in Table 2 confirms the high selectivity of

ethylene noticed in theODHof ethane over theW006

catalystApparent activation energies of 605plusmn80 1396plusmn157 924plusmn139 and 241plusmn22 kJmol were obtained for the ethane ODH(1198641) ethane combustion (119864

2) alkene combustion (119864

3) and


Table 3 Correlation matrix for the ODH of ethane on the W006 catalyst

1198961

1198641

1198962

1198642

1198963

1198643

1198964

1198644

1198961

10000 minus00418 minus01419 00091 minus08099 06532 minus08724 057091198641

minus00418 10000 00134 minus00920 02143 minus04422 01922 minus060741198962







the formation of CH3COOH from C

2H4(1198644) respectively

following the order of 1198644lt 1198641lt 1198643lt 1198642 Recently Lin et

al [33] reported apparent activation energy of sim515 kJmolfor the formation of ethylene over a K-Y zeolite Similarly anapparent activation energy (119864

1) of sim632 kJmol was reported

for the formation of ethylene over VOxSiO2 catalyst [6]These values are in good agreement with that calculatedover the W

006catalyst Argyle and coworkers [7] reported

apparent activation energies sim115 kJmol and sim60ndash90 kJmolfor ethane combustion (119864

2) and alkene combustion (119864

3)

respectively over an alumina-supported vanadia catalystTheapparent activation energies obtained for ethane and ethylenecombustion to form carbon oxides in this present studyshow a similar order of magnitude with those reported inthe literature Using the estimated kinetic parameters wecarried out kinetic modeling to examine the validity of thesimulated results and compared them with our experimentsfinding (ie Figures 5 and 9) The fitted parameters weresubstituted into the comprehensive model developed for thisscheme and the equations were solved numerically by usingthe 4th-order-Runge-Kutta routine It was found that ourprediction is in good agreement with experiment (Figures 5and 9) demonstrating the validity of the proposed kineticmodel It is assumed that the slight deviation observed inFigure 9 at 275∘Cmight be due to the significant side productsgenerated at this reaction temperature It is proposed tocarry out microkinetic modeling based on a mechanisticstudy using density functional theory (DFT) simulations [4849] providing more detailed information of the conversionselectivity and yield of C

2H4 CH3COOH CO and CO

2

on W-doped surfaces The DFT based study would facilitaterationally design of novel MoVMnWmixed oxide catalysts

4 Conclusions

MoVMnW mixed oxide catalysts were revisited to examinethe ODH of ethane It was found that the addition ofW to MoVMn mixed oxide catalysts improves the cat-alytic activity toward C

2H4 while lowering the formation

of by-products (CH3COOH CO and CO

2) Using the

MoV04Mn018

W0063

Ox (W006) catalyst we observed that theprimary product of ethane oxidation is ethylene which maygo through consecutive reactions to CH

3COOH CO and

CO2The best selectivity of ethylene on the catalyst wassim90

at 235∘C However a significant decrease in the selectivity of

0

5

10

15

20

0 5 10 15 20 25

Yet

hyle

ne(

)

Xethane ()

235∘C

255∘C

275∘C

Figure 9 Ethylene yield versus ethane conversion at the reactiontemperatures of 235 255 and 275∘C The solid dashed and dottedcurves are predicted results based on the kinetic model

ethylenewas observed by increasing the reaction temperaturefrom 235∘C to 275∘C

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgments

The authors highly appreciated the financial support bySABIC YongMan Choi acknowledges the technical discus-sion with Professor Ming-Kang Tsai The authors thank thereviewersrsquo valuable comments which have improved theirpaper substantially

References

[1] S Seifzadeh Haghighi M R Rahimpour S Raeissi and ODehghani ldquoInvestigation of ethylene production in naphthathermal cracking plant in presence of steam and carbon diox-iderdquo Chemical Engineering Journal vol 228 pp 1158ndash1167 2013


[2] C A Gartner A C vanVeen and J A Lercher ldquoOxidativedehydrogenation of ethane common principles and mechanis-tic aspectsrdquo ChemCatChem vol 5 no 11 pp 3196ndash3217 2013

[3] X Lin C A Hoel W M H Sachtler K R Poeppelmeier andEWeitz ldquoOxidative dehydrogenation (ODH) of ethane withO

2

as oxidant on selected transition metal-loaded zeolitesrdquo Journalof Catalysis vol 265 no 1 pp 54ndash62 2009

[4] M L Rodriguez D E Ardissone E Heracleous et al ldquoOxida-tive dehydrogenation of ethane to ethylene in a membranereactor a theoretical studyrdquo Catalysis Today vol 157 no 1ndash4pp 303ndash309 2010

[5] AMachocki andA Denis ldquoSimultaneous oxidative coupling ofmethane and oxidative dehydrogenation of ethane on the Na+CaO catalystrdquoChemical Engineering Journal vol 90 no 1-2 pp165ndash172 2002

[6] R Grabowski and J Słoczynski ldquoKinetics of oxidative dehy-drogenation of propane and ethane on VO

119909

SiO2

pure andwith potassium additiverdquo Chemical Engineering and ProcessingProcess Intensification vol 44 no 10 pp 1082ndash1093 2005

[7] M D Argyle K Chen A T Bell and E Iglesia ldquoEffect ofcatalyst structure on oxidative dehydrogenation of ethane andpropane on alumina-supported vanadiardquo Journal of Catalysisvol 208 no 1 pp 139ndash149 2002

[8] F Cavani N Ballarini and A Cericola ldquoOxidative dehydro-genation of ethane and propane how far from commercialimplementationrdquo Catalysis Today vol 127 no 1ndash4 pp 113ndash1312007

[9] C SatterfieldHeterogeneous Catalysis in PracticeMcGraw-HillNew York NY USA 1980

[10] L Capek J Adam T Grygar et al ldquoOxidative dehydrogenationof ethane over vanadium supported on mesoporous materialsof M41S familyrdquo Applied Catalysis A General vol 342 no 1-2pp 99ndash106 2008

[11] T Blasco A Galli J M Lopez Nieto and F Trifiro ldquoOxidativedehydrogenation of ethane and n-butane on VOxAl

2

O3

cata-lystsrdquo Journal of Catalysis vol 169 no 1 pp 203ndash211 1997

[12] G Tsilomelekis A Christodoulakis and S Boghosian ldquoSup-port effects on structure and activity of molybdenum oxidecatalysts for the oxidative dehydrogenation of ethanerdquo CatalysisToday vol 127 no 1ndash4 pp 139ndash147 2007

[13] C Liu and U S Ozkan ldquoEffect of chlorine on redox andadsorption characteristics of MoSiTi catalysts in the oxidativedehydrogenation of ethanerdquo Journal of Molecular Catalysis AChemical vol 220 no 1 pp 53ndash65 2004

[14] A Khodakov B Olthof A T Bell and E Iglesia ldquoStructureand catalytic properties of supported vanadium oxides supporteffects on oxidative dehydrogenation reactionsrdquo Journal ofCatalysis vol 181 no 2 pp 205ndash216 1999

[15] A Corma J M L Nieto and N Paredes ldquoInfluence of thepreparation methods of V-Mg-O catalysts on their catalyticproperties for the oxidative dehydrogenation of propanerdquo Jour-nal of Catalysis vol 144 no 2 pp 425ndash438 1993

[16] P Botella A Dejoz J M L Nieto P Concepcion and M IVazquez ldquoSelective oxidative dehydrogenation of ethane overMoVSbO mixed oxide catalystsrdquo Applied Catalysis A Generalvol 298 no 1-2 pp 16ndash23 2006

[17] M V Martınez-Huerta X Gao H Tian I E Wachs J LG Fierro and M A Banares ldquoOxidative dehydrogenation ofethane to ethylene over alumina-supported vanadium oxidecatalysts relationship between molecular structures and chem-ical reactivityrdquo Catalysis Today vol 118 no 3-4 pp 279ndash2872006

[18] Z-S Chao and E Ruckenstein ldquoNoncatalytic and catalyticconversion of ethane over V-Mg oxide catalysts prepared viasolid reaction or mesoporous precursorsrdquo Journal of Catalysisvol 222 no 1 pp 17ndash31 2004

[19] R B Watson S L Lashbrook and U S Ozkan ldquoChlorinemodification of Mosilica-titania mixed-oxide catalysts for theoxidative dehydrogenation of ethanerdquo Journal of MolecularCatalysis A Chemical vol 208 no 1-2 pp 233ndash244 2004

[20] R B Watson and U S Ozkan ldquoMo loading effects over MoSiTi catalysts in the oxidative dehydrogenation of ethanerdquo Journalof Catalysis vol 208 no 1 pp 124ndash138 2002

[21] G Grubert E Kondratenko S Kolf M Baerns P VanGeem and R Parton ldquoFundamental insights into the oxidativedehydrogenation of ethane to ethylene over catalytic materialsdiscovered by an evolutionary approachrdquo Catalysis Today vol81 no 3 pp 337ndash345 2003

[22] C Yokoyama S S Bharadwaj and L D Schmidt ldquoPlatinum-tin and platinum-copper catalysts for autothermal oxidativedehydrogenation of ethane to ethylenerdquo Catalysis Letters vol38 no 3-4 pp 181ndash188 1996

[23] D W Flick and M C Huff ldquoOxidative dehydrogenationof ethane over supported chromium oxide and Pt modifiedchromium oxiderdquo Applied Catalysis A General vol 187 no 1pp 13ndash24 1999

[24] G D Claycomb P M A Sherwood B E Traxel and K LHohn ldquoX-ray photoelectron spectroscopic study of the surfacestate during ethane oxidative dehydrogenation at millisecondcontact timesrdquoThe Journal of Physical Chemistry C vol 111 no50 pp 18724ndash18730 2007

[25] E A de Graaf G Rothenberg P J Kooyman A Andreini andA Bliek ldquoPt002Sn0003Mg006 on 120574-alumina a stable catalystfor oxidative dehydrogenation of ethanerdquo Applied Catalysis AGeneral vol 278 no 2 pp 187ndash194 2005

[26] B Solsona A Dejoz T Garcia et al ldquoMolybdenum-vanadiumsupported on mesoporous alumina catalysts for the oxidativedehydrogenation of ethanerdquoCatalysis Today vol 117 no 1-3 pp228ndash233 2006

[27] MRousselM Bouchard K Karim S Al-Sayari andE Bordes-Richard ldquoMoVO-based catalysts for the oxidation of ethane toethylene and acetic acid influence of niobium andor palladiumon physicochemical and catalytic propertiesrdquo Applied CatalysisA General vol 308 pp 62ndash74 2006

[28] Q Xie L Chen W Weng and H Wan ldquoPreparation ofMoVTe(Sb)Nb mixed oxide catalysts using a slurry methodfor selective oxidative dehydrogenation of ethanerdquo Journal ofMolecular Catalysis A Chemical vol 240 no 1-2 pp 191ndash1962005

[29] D Linke D Wolf M Baerns et al ldquoCatalytic partial oxidationof ethane to acetic acid over Mo

1

V025

Nb012Pd00005

O119909

ICatalyst performance and reaction mechanismrdquo Journal ofCatalysis vol 205 no 1 pp 16ndash31 2002

[30] D Linke D Wolf M Baerns S Zeyszlig U Dingerdissen and LMleczko ldquoCatalytic partial oxidation of ethane to acetic acidover Mo

1

V025

Nb012

Pd00005

O119909

reactor operationrdquo ChemicalEngineering Science vol 57 no 1 pp 39ndash51 2002

[31] D Linke D Wolf M Baerns S Zeyszlig and U Dingerdis-sen ldquoCatalytic partial oxidation of ethane to acetic acid overMo1

V025

Nb012

Pd00005

O119909

II Kinetic modellingrdquo Journal ofCatalysis vol 205 no 1 pp 32ndash43 2002


[32] E M Thorsteinson T P Wilson F G Young and P H KasaildquoThe oxidative dehydrogenation of ethane over catalysts con-taining mixed oxides of molybdenum and vanadiumrdquo Journalof Catalysis vol 52 no 1 pp 116ndash132 1978

[33] X Lin K R Poeppelmeier and E Weitz ldquoOxidative dehy-drogenation of ethane with oxygen catalyzed by K-Y zeolitesupported first-row transition metalsrdquo Applied Catalysis AGeneral vol 381 no 1-2 pp 114ndash120 2010

[34] D Vitry Y Morikawa J L Dubois and W Ueda ldquoMo-V-Te-(Nb)-O mixed metal oxides prepared by hydrothermal synthe-sis for catalytic selective oxidations of propane and propene toacrylic acidrdquo Applied Catalysis A General vol 251 no 2 pp411ndash424 2003

[35] K Karim A Mamedov M H Al-Hazmi and N Al-AndisldquoOxidative dehydrogenation of ethane over MoVMnW oxidecatalystsrdquo Reaction Kinetics and Catalysis Letters vol 80 no 1pp 3ndash11 2003

[36] K S Karim M H Al-Hazmi and N Al-Andis ldquoCatalystsfor oxidative dehydrogenation of ethanerdquo Arabian Journal forScience and Engineering vol 24 no 1 pp 41ndash48 1999

[37] J Tichy ldquoOxidation of acrolein to acrylic acid over vanadium-molybdenum oxide catalystsrdquo Applied Catalysis A General vol157 no 1-2 pp 363ndash385 1997

[38] T Blasco J M L Nieto A Dejoz andM I Vazquez ldquoInfluenceof the acid-base character of supported vanadium catalysts ontheir catalytic properties for the oxidative dehydrogenation ofn-butanerdquo Journal of Catalysis vol 157 no 2 pp 271ndash282 1995

[39] A Dejoz J M Lopez Nieto F Marquez and M I VazquezldquoThe role of molybdenum in Mo-doped V-Mg-O catalystsduring the oxidative dehydrogenation of 119899-butanerdquo AppliedCatalysis A General vol 180 no 1-2 pp 83ndash94 1999

[40] J Guan H Xu K Song et al ldquoSelective oxidation and oxidativedehydrogenation of isobutane over hydrothermally synthesizedMo-V-O mixed oxide catalystsrdquo Catalysis Letters vol 126 no3-4 pp 293ndash300 2008

[41] E R Stobbe B A de Boer and J W Geus ldquoThe reduction andoxidation behaviour of manganese oxidesrdquoCatalysis Today vol47 no 1ndash4 pp 161ndash167 1999

[42] B Solsona J M Lopez Nieto P Concepcion A Dejoz F Ivarsand M I Vazquez ldquoOxidative dehydrogenation of ethane overNi-W-O mixed metal oxide catalystsrdquo Journal of Catalysis vol280 no 1 pp 28ndash39 2011

[43] P Botella E Garcıa-Gonzalez A Dejoz J M Lopez NietoM I Vazquez and J Gonzalez-Calbet ldquoSelective oxidativedehydrogenation of ethane on MoVTeNbO mixed metal oxidecatalystsrdquo Journal of Catalysis vol 225 no 2 pp 428ndash438 2004

[44] M D Argyle K Chen A T Bell and E Iglesia ldquoEthane oxida-tive dehydrogenation pathways on vanadium oxide catalystsrdquoJournal of Physical Chemistry B vol 106 no 21 pp 5421ndash54272002

[45] S Al-Khattaf J A Atias K Jarosch and H de Lasa ldquoDiffusionand catalytic cracking of 135 tri-iso-propyl-benzene in FCCcatalystsrdquo Chemical Engineering Science vol 57 no 22-23 pp4909ndash4920 2002

[46] A Voorhies ldquoCarbon formation in catalytic crackingrdquo Indus-trial amp Engineering Chemistry vol 37 no 4 pp 318ndash322 1945

[47] A K Agarwal andM L Brisk ldquoSequential experimental designfor precise parameter estimation 1 Use of reparameterizationrdquoIndustrial amp Engineering Chemistry Process Design and Develop-ment vol 24 pp 203ndash207 1986

[48] Y Choi and P Liu ldquoMechanism of ethanol synthesis fromsyngas on Rh(111)rdquo Journal of the American Chemical Societyvol 131 no 36 pp 13054ndash13061 2009

[49] Y Choi and P Liu ldquoUnderstanding of ethanol decompositionon Rh(1 1 1) from density functional theory and kinetic MonteCarlo simulationsrdquo Catalysis Today vol 165 no 1 pp 64ndash702011

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy


Carbohydrate Chemistry

International Journal of


Journal of

Chemistry


Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of


Chromatography Research International


Applied ChemistryJournal of



Theoretical ChemistryJournal of


Journal of

Spectroscopy

Analytical ChemistryInternational Journal of


Journal of


Quantum Chemistry


Organic Chemistry International

ElectrochemistryInternational Journal of



CatalystsJournal of


for the ODH of ethane we investigated the effect of variousreaction conditions (ie contact time reaction temperatureand conversion) on the selectivities of ethylene acetic acidand COx

2 Experimental

21 Catalyst Preparation Asmentioned 63mol ofW dop-ing toMoVMnmixed oxide catalysts showed the best conver-sion of ethane by the ODH [35] Based on the previous studywe applied three materials of MoV

04Mn018

W0Ox (W

0)

MoV04Mn018

W0063

Ox (W006

) and MoV04Mn018

W014

Ox(W014

) We considered W0and W

014as the extreme cases

without W and the highest doping respectively andW006

asthe optimal one in terms of the ethane conversion from theODH The synthesis method is described in detail elsewhere[36] Briefly ammoniummetavanadate (FlukaChemical) wasadded to deionized water and heated to 85∘C with a constantstirring A yellow colored solution was obtained Oxalic acid(Riedel-de Haen Chemicals) was added with water to thesolution with constant stirring while the required amountof ammonium tungstate (BDH Chemicals) and manganeseacetate (Riedel-de Haen Chemicals resp) was slowly addedto themixtureThen ammoniumheptamolybdate (Riedel-deHaen Chemicals) was added to the solution Precipitates weredried in an oven at 120∘C and calcined at 350∘C for 4 hoursThe calcined catalysts were screened into uniform particles ofa 4060mesh

22 Characterization of Catalysts The samples were char-acterized using several characterization tools including X-ray diffraction (XRD) It was recorded on a Mac ScienceMX18XHF-SRA powder diffractometer with monochroma-tized Cu K120572 radiation (120582 = 0154 nm) at 40 kV and 30mAA Micromeritics AutoChem II 2920 with a thermal con-ductivity detector (TCD) was used for the H

2temperature-

programmed reduction (TPR) analysis to study the reductionproperties of the samples 15ndash20mg of the catalyst sampleswas heated from 40∘C to 1000∘C at a heating rate of 10∘Cminin 10 H

2in Ar Before the H

2-TPR analysis the samples

were heated for 60min in Ar flow at 100∘C The profile ofconsumed H

2was recorded by the TCD Scanning electron

microscopy (SEM) images were recorded using a JEOL JSM-5500LV Surface area calculations were carried out usingThe Brunauer-Emmett-Teller (BET) method Adsorptionisotherms were measured in Quantachrome AUTO-SORB-1at minus196∘C

23 Reaction Apparatus and Procedures Catalytic experi-ments were carried out in a fixed-bed reactor (ID = 078 cm)with the contact times of 008 012 016 024 032 049and 065 sec The contact time was changed by varying theweight of the catalyst in the range of 50ndash400mg and at atotal flow of 30mLmin All experiments were carried out at235 255 and 275∘C and at 200 psi The gas feed compositionused in this study was fixed at 15 vol ethane in 85 vol airTo avoid any mass resistance problem of feed the preparedpowder was pressed to pellets then crushed and sieved to

(a)

6 6 123 3 3 42 2 2 5 2 77

(b)

(c)

10 20 30 40 50 60

Inte

nsity

(au

)

2120579 (deg)

Figure 1 XRD patterns of (a) W0

(b) W006

and (c) W014

calcinedat 400∘C The numbers (1 2 3 4 5 6 and 7) on the top 119909-axiscorrespond toWO

3

orWO4

MoO3

Mo suboxide such asMo8

O23

orMo9

O26

(MxMo1minusx)5O14 (M=V orMn orW)W

3

OV095

Mo097

O5

and Mn

2

O3

respectively

200 400 600 800 1000

Temperature (∘C)

H2

cons

umpt

ion

(au

)

677∘C

769∘C

772∘C

(a)

(b)

(c)

Figure 2 H2

-TPR profiles of (a) W0

(b) W006

and (c) W014

cata-lysts The dashed lines are the reduction peaks

40ndash60mesh particles Reactants and products were analyzedusing an online gas chromatograph equipped with a doubledetector (ie thermal conductivity detector (TCD) and flameionization detector (FID)) and two columns of HayeSep D80100mesh and LAC446 We confirmed the reproducibilityof the experiment results within the uncertainty of plusmn2Then we obtained the conversion (119883ethane) selectivity toproduct 119894 (119878

119894) and yield to product 119894 (119884

119894)

3 Results and Discussion

31 Characterization of Samples Crystalline phases of thethree catalysts were characterized by XRD Figure 1 showsXRD patterns of W

0 W006

and W014

calcined at 400∘CMo suboxides (ie Mo

8O23

(or Mo9O26) MoO

3 and

(VxMo1minusx)5O14) were noticed as the major phases (Figure 1)


(a)

(b)

(c)


(b) W006

and (c) W014






Mo097

O5(JCPDS



W006

and W014




0at 587∘C


2uptake


2O3[41] The


006) and 772∘C (W




006 the H



W006


006versus W

014)


andW014


0without W









25

20

15

10

5

Xet

hane

()

0 2 4 6 8 10 12 14

60

30

0

C2H4

CH3COOH

CO

CO2

Si

()

W ()












2at 235 255



25

20

15

10

5

0

00 01 02 03 04 05 06 07

Time (s)

235∘C

255∘C

275∘C

Xet

hane

()


006



18

16

14

12

10

8

6

4

2

0255 275

C2H4

CH3COOHCOx

Yi

()







00 01 02 03 04 05 06 07

0

5

10

15

20

COCO2

CH3COOH

Si

()

Time (s)

(a)

00 01 02 03 04 05 06 07

Time (s)

95

90

85

80

75

70

Set

hyle

ne(

)

235∘C

255∘C

275∘C

(b)


COOH CO and CO2


006

catalyst





006catalyst


2H6


2H4


(119903CO119909


minus119889119862C

2H6

119889119905120591

= (1198961119862C2H6

119862O2

+ 1198962119862C2H6

119862O2

) sdot 120593 (1)

119889119862C2H4

119889119905120591

= (1198961119862C2H6

119862O2

minus 1198963119862C2H4

119862O2

minus 1198964119862C2H4

119862O2

) sdot 120593

(2)

119889119862CH3COOH

119889119905120591

= (1198964119862C2H4

119862O2

) sdot 120593 (3)

119889119862CO119909

119889119905120591

= (1198962119862C2H6

119862O2

+ 1198963119862C2H4

119862O2

) sdot 120593 (4)

C2H6 C2H4 + H2O+O2+O2

CH3COOH

COx

k1

k2 k3

k4





120591= 120591)






relation

119862119909=

119910119909119865TM

120592119900MW119909

(5)






0 5 10 15 20

0

5

10

15

20Si

()

Xethane ()

COCO2

CH3COOH

(a)

70

75

80

85

90

95

Set

hyle

ne(

)

235∘C

255∘C

275∘C

0 5 10 15 20

Xethane ()

(b)


COOH CO and CO2


006



minus119889119910C2H6

119889119905120591

= 1198691(1198961119910C2H6

119910O2

+ 1198962119910C2H6

119910O2

) exp (minus120572119905) (6)

119889119910C2H4

119889119905120591

= (11986921198961119910C2H6

119910O2

minus 11986911198963119910C2H4

119910O2

minus 11986911198964119910C2H4

119910O2

)

sdot exp (minus120572119905)(7)

119889119910CH3COOH

119889119905120591

= (11986931198964119910C2H4

119910O2

) exp (minus120572119905) (8)

119889119910CO119909

119889119905120591

= (11986941198962119910C2H6

119910O2

+ 11986951198963119910C2H4

119910O2

) exp (minus120572119905) (9)

where 1198691 1198692 1198693 1198694 and 119869


1=

119865TM120592119900MWO2

1198692= 119865TMMWC

2H4

120592119900MWC

2H6

MWO2

1198693=


2H4

MWO2

1198694

= 119865TMMWCO119909

120592119900MWC

2H6

MWO2

and 1198695= 119865TMMWCO

119909

120592119900MWC

2H4

MWO2


119896119894= 119896119900119894exp [

minus119864119894

119877(1

119879minus

1

119879119900

)] (10)








1198962

1198963

1198964

120572

119864119894

(kJmol) 605 1396 924 241 00395 CL 80 157 139 22119896119900119894

times 104 (sminus1) 0670 0045 0310 0810

95 CL times 104 0005 0016 0012 0053






1and 119896

2can be used to


11198962and 119896



1and low val-


1 1198962 1198963 and





3) and



1198961

1198641

1198962

1198642

1198963

1198643

1198964

1198644

1198961


















3)



2


4 Conclusions




2) Using the

MoV04Mn018

W0063


3COOH CO and



0

5

10

15

20

0 5 10 15 20 25

Yet

hyle

ne(

)

Xethane ()

235∘C

255∘C

275∘C





Acknowledgments


References





2





119909

SiO2







2

O3




















1

V025

Nb012Pd00005

O119909



1

V025

Nb012

Pd00005

O119909



V025

Nb012

Pd00005

O119909






























Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


(a)

(b)

(c)


(b) W006

and (c) W014






Mo097

O5(JCPDS



W006

and W014




0at 587∘C


2uptake


2O3[41] The


006) and 772∘C (W




006 the H



W006


006versus W

014)


andW014


0without W









25

20

15

10

5

Xet

hane

()

0 2 4 6 8 10 12 14

60

30

0

C2H4

CH3COOH

CO

CO2

Si

()

W ()












2at 235 255



25

20

15

10

5

0

00 01 02 03 04 05 06 07

Time (s)

235∘C

255∘C

275∘C

Xet

hane

()


006



18

16

14

12

10

8

6

4

2

0255 275

C2H4

CH3COOHCOx

Yi

()







00 01 02 03 04 05 06 07

0

5

10

15

20

COCO2

CH3COOH

Si

()

Time (s)

(a)

00 01 02 03 04 05 06 07

Time (s)

95

90

85

80

75

70

Set

hyle

ne(

)

235∘C

255∘C

275∘C

(b)


COOH CO and CO2


006

catalyst





006catalyst


2H6


2H4


(119903CO119909


minus119889119862C

2H6

119889119905120591

= (1198961119862C2H6

119862O2

+ 1198962119862C2H6

119862O2

) sdot 120593 (1)

119889119862C2H4

119889119905120591

= (1198961119862C2H6

119862O2

minus 1198963119862C2H4

119862O2

minus 1198964119862C2H4

119862O2

) sdot 120593

(2)

119889119862CH3COOH

119889119905120591

= (1198964119862C2H4

119862O2

) sdot 120593 (3)

119889119862CO119909

119889119905120591

= (1198962119862C2H6

119862O2

+ 1198963119862C2H4

119862O2

) sdot 120593 (4)

C2H6 C2H4 + H2O+O2+O2

CH3COOH

COx

k1

k2 k3

k4





120591= 120591)






relation

119862119909=

119910119909119865TM

120592119900MW119909

(5)






0 5 10 15 20

0

5

10

15

20Si

()

Xethane ()

COCO2

CH3COOH

(a)

70

75

80

85

90

95

Set

hyle

ne(

)

235∘C

255∘C

275∘C

0 5 10 15 20

Xethane ()

(b)


COOH CO and CO2


006



minus119889119910C2H6

119889119905120591

= 1198691(1198961119910C2H6

119910O2

+ 1198962119910C2H6

119910O2

) exp (minus120572119905) (6)

119889119910C2H4

119889119905120591

= (11986921198961119910C2H6

119910O2

minus 11986911198963119910C2H4

119910O2

minus 11986911198964119910C2H4

119910O2

)

sdot exp (minus120572119905)(7)

119889119910CH3COOH

119889119905120591

= (11986931198964119910C2H4

119910O2

) exp (minus120572119905) (8)

119889119910CO119909

119889119905120591

= (11986941198962119910C2H6

119910O2

+ 11986951198963119910C2H4

119910O2

) exp (minus120572119905) (9)

where 1198691 1198692 1198693 1198694 and 119869


1=

119865TM120592119900MWO2

1198692= 119865TMMWC

2H4

120592119900MWC

2H6

MWO2

1198693=


2H4

MWO2

1198694

= 119865TMMWCO119909

120592119900MWC

2H6

MWO2

and 1198695= 119865TMMWCO

119909

120592119900MWC

2H4

MWO2


119896119894= 119896119900119894exp [

minus119864119894

119877(1

119879minus

1

119879119900

)] (10)








1198962

1198963

1198964

120572

119864119894

(kJmol) 605 1396 924 241 00395 CL 80 157 139 22119896119900119894

times 104 (sminus1) 0670 0045 0310 0810

95 CL times 104 0005 0016 0012 0053






1and 119896

2can be used to


11198962and 119896



1and low val-


1 1198962 1198963 and





3) and



1198961

1198641

1198962

1198642

1198963

1198643

1198964

1198644

1198961


















3)



2


4 Conclusions




2) Using the

MoV04Mn018

W0063


3COOH CO and



0

5

10

15

20

0 5 10 15 20 25

Yet

hyle

ne(

)

Xethane ()

235∘C

255∘C

275∘C





Acknowledgments


References





2





119909

SiO2







2

O3




















1

V025

Nb012Pd00005

O119909



1

V025

Nb012

Pd00005

O119909



V025

Nb012

Pd00005

O119909






























Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


25

20

15

10

5

Xet

hane

()

0 2 4 6 8 10 12 14

60

30

0

C2H4

CH3COOH

CO

CO2

Si

()

W ()












2at 235 255



25

20

15

10

5

0

00 01 02 03 04 05 06 07

Time (s)

235∘C

255∘C

275∘C

Xet

hane

()


006



18

16

14

12

10

8

6

4

2

0255 275

C2H4

CH3COOHCOx

Yi

()







00 01 02 03 04 05 06 07

0

5

10

15

20

COCO2

CH3COOH

Si

()

Time (s)

(a)

00 01 02 03 04 05 06 07

Time (s)

95

90

85

80

75

70

Set

hyle

ne(

)

235∘C

255∘C

275∘C

(b)


COOH CO and CO2


006

catalyst





006catalyst


2H6


2H4


(119903CO119909


minus119889119862C

2H6

119889119905120591

= (1198961119862C2H6

119862O2

+ 1198962119862C2H6

119862O2

) sdot 120593 (1)

119889119862C2H4

119889119905120591

= (1198961119862C2H6

119862O2

minus 1198963119862C2H4

119862O2

minus 1198964119862C2H4

119862O2

) sdot 120593

(2)

119889119862CH3COOH

119889119905120591

= (1198964119862C2H4

119862O2

) sdot 120593 (3)

119889119862CO119909

119889119905120591

= (1198962119862C2H6

119862O2

+ 1198963119862C2H4

119862O2

) sdot 120593 (4)

C2H6 C2H4 + H2O+O2+O2

CH3COOH

COx

k1

k2 k3

k4





120591= 120591)






relation

119862119909=

119910119909119865TM

120592119900MW119909

(5)






0 5 10 15 20

0

5

10

15

20Si

()

Xethane ()

COCO2

CH3COOH

(a)

70

75

80

85

90

95

Set

hyle

ne(

)

235∘C

255∘C

275∘C

0 5 10 15 20

Xethane ()

(b)


COOH CO and CO2


006



minus119889119910C2H6

119889119905120591

= 1198691(1198961119910C2H6

119910O2

+ 1198962119910C2H6

119910O2

) exp (minus120572119905) (6)

119889119910C2H4

119889119905120591

= (11986921198961119910C2H6

119910O2

minus 11986911198963119910C2H4

119910O2

minus 11986911198964119910C2H4

119910O2

)

sdot exp (minus120572119905)(7)

119889119910CH3COOH

119889119905120591

= (11986931198964119910C2H4

119910O2

) exp (minus120572119905) (8)

119889119910CO119909

119889119905120591

= (11986941198962119910C2H6

119910O2

+ 11986951198963119910C2H4

119910O2

) exp (minus120572119905) (9)

where 1198691 1198692 1198693 1198694 and 119869


1=

119865TM120592119900MWO2

1198692= 119865TMMWC

2H4

120592119900MWC

2H6

MWO2

1198693=


2H4

MWO2

1198694

= 119865TMMWCO119909

120592119900MWC

2H6

MWO2

and 1198695= 119865TMMWCO

119909

120592119900MWC

2H4

MWO2


119896119894= 119896119900119894exp [

minus119864119894

119877(1

119879minus

1

119879119900

)] (10)








1198962

1198963

1198964

120572

119864119894

(kJmol) 605 1396 924 241 00395 CL 80 157 139 22119896119900119894

times 104 (sminus1) 0670 0045 0310 0810

95 CL times 104 0005 0016 0012 0053






1and 119896

2can be used to


11198962and 119896



1and low val-


1 1198962 1198963 and





3) and



1198961

1198641

1198962

1198642

1198963

1198643

1198964

1198644

1198961


















3)



2


4 Conclusions




2) Using the

MoV04Mn018

W0063


3COOH CO and



0

5

10

15

20

0 5 10 15 20 25

Yet

hyle

ne(

)

Xethane ()

235∘C

255∘C

275∘C





Acknowledgments


References





2





119909

SiO2







2

O3




















1

V025

Nb012Pd00005

O119909



1

V025

Nb012

Pd00005

O119909



V025

Nb012

Pd00005

O119909






























Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


00 01 02 03 04 05 06 07

0

5

10

15

20

COCO2

CH3COOH

Si

()

Time (s)

(a)

00 01 02 03 04 05 06 07

Time (s)

95

90

85

80

75

70

Set

hyle

ne(

)

235∘C

255∘C

275∘C

(b)


COOH CO and CO2


006

catalyst





006catalyst


2H6


2H4


(119903CO119909


minus119889119862C

2H6

119889119905120591

= (1198961119862C2H6

119862O2

+ 1198962119862C2H6

119862O2

) sdot 120593 (1)

119889119862C2H4

119889119905120591

= (1198961119862C2H6

119862O2

minus 1198963119862C2H4

119862O2

minus 1198964119862C2H4

119862O2

) sdot 120593

(2)

119889119862CH3COOH

119889119905120591

= (1198964119862C2H4

119862O2

) sdot 120593 (3)

119889119862CO119909

119889119905120591

= (1198962119862C2H6

119862O2

+ 1198963119862C2H4

119862O2

) sdot 120593 (4)

C2H6 C2H4 + H2O+O2+O2

CH3COOH

COx

k1

k2 k3

k4





120591= 120591)






relation

119862119909=

119910119909119865TM

120592119900MW119909

(5)






0 5 10 15 20

0

5

10

15

20Si

()

Xethane ()

COCO2

CH3COOH

(a)

70

75

80

85

90

95

Set

hyle

ne(

)

235∘C

255∘C

275∘C

0 5 10 15 20

Xethane ()

(b)


COOH CO and CO2


006



minus119889119910C2H6

119889119905120591

= 1198691(1198961119910C2H6

119910O2

+ 1198962119910C2H6

119910O2

) exp (minus120572119905) (6)

119889119910C2H4

119889119905120591

= (11986921198961119910C2H6

119910O2

minus 11986911198963119910C2H4

119910O2

minus 11986911198964119910C2H4

119910O2

)

sdot exp (minus120572119905)(7)

119889119910CH3COOH

119889119905120591

= (11986931198964119910C2H4

119910O2

) exp (minus120572119905) (8)

119889119910CO119909

119889119905120591

= (11986941198962119910C2H6

119910O2

+ 11986951198963119910C2H4

119910O2

) exp (minus120572119905) (9)

where 1198691 1198692 1198693 1198694 and 119869


1=

119865TM120592119900MWO2

1198692= 119865TMMWC

2H4

120592119900MWC

2H6

MWO2

1198693=


2H4

MWO2

1198694

= 119865TMMWCO119909

120592119900MWC

2H6

MWO2

and 1198695= 119865TMMWCO

119909

120592119900MWC

2H4

MWO2


119896119894= 119896119900119894exp [

minus119864119894

119877(1

119879minus

1

119879119900

)] (10)








1198962

1198963

1198964

120572

119864119894

(kJmol) 605 1396 924 241 00395 CL 80 157 139 22119896119900119894

times 104 (sminus1) 0670 0045 0310 0810

95 CL times 104 0005 0016 0012 0053






1and 119896

2can be used to


11198962and 119896



1and low val-


1 1198962 1198963 and





3) and



1198961

1198641

1198962

1198642

1198963

1198643

1198964

1198644

1198961


















3)



2


4 Conclusions




2) Using the

MoV04Mn018

W0063


3COOH CO and



0

5

10

15

20

0 5 10 15 20 25

Yet

hyle

ne(

)

Xethane ()

235∘C

255∘C

275∘C





Acknowledgments


References





2





119909

SiO2







2

O3




















1

V025

Nb012Pd00005

O119909



1

V025

Nb012

Pd00005

O119909



V025

Nb012

Pd00005

O119909






























Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


0 5 10 15 20

0

5

10

15

20Si

()

Xethane ()

COCO2

CH3COOH

(a)

70

75

80

85

90

95

Set

hyle

ne(

)

235∘C

255∘C

275∘C

0 5 10 15 20

Xethane ()

(b)


COOH CO and CO2


006



minus119889119910C2H6

119889119905120591

= 1198691(1198961119910C2H6

119910O2

+ 1198962119910C2H6

119910O2

) exp (minus120572119905) (6)

119889119910C2H4

119889119905120591

= (11986921198961119910C2H6

119910O2

minus 11986911198963119910C2H4

119910O2

minus 11986911198964119910C2H4

119910O2

)

sdot exp (minus120572119905)(7)

119889119910CH3COOH

119889119905120591

= (11986931198964119910C2H4

119910O2

) exp (minus120572119905) (8)

119889119910CO119909

119889119905120591

= (11986941198962119910C2H6

119910O2

+ 11986951198963119910C2H4

119910O2

) exp (minus120572119905) (9)

where 1198691 1198692 1198693 1198694 and 119869


1=

119865TM120592119900MWO2

1198692= 119865TMMWC

2H4

120592119900MWC

2H6

MWO2

1198693=


2H4

MWO2

1198694

= 119865TMMWCO119909

120592119900MWC

2H6

MWO2

and 1198695= 119865TMMWCO

119909

120592119900MWC

2H4

MWO2


119896119894= 119896119900119894exp [

minus119864119894

119877(1

119879minus

1

119879119900

)] (10)








1198962

1198963

1198964

120572

119864119894

(kJmol) 605 1396 924 241 00395 CL 80 157 139 22119896119900119894

times 104 (sminus1) 0670 0045 0310 0810

95 CL times 104 0005 0016 0012 0053






1and 119896

2can be used to


11198962and 119896



1and low val-


1 1198962 1198963 and





3) and



1198961

1198641

1198962

1198642

1198963

1198643

1198964

1198644

1198961


















3)



2


4 Conclusions




2) Using the

MoV04Mn018

W0063


3COOH CO and



0

5

10

15

20

0 5 10 15 20 25

Yet

hyle

ne(

)

Xethane ()

235∘C

255∘C

275∘C





Acknowledgments


References





2





119909

SiO2







2

O3




















1

V025

Nb012Pd00005

O119909



1

V025

Nb012

Pd00005

O119909



V025

Nb012

Pd00005

O119909






























Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of



1198961

1198641

1198962

1198642

1198963

1198643

1198964

1198644

1198961


















3)



2


4 Conclusions




2) Using the

MoV04Mn018

W0063


3COOH CO and



0

5

10

15

20

0 5 10 15 20 25

Yet

hyle

ne(

)

Xethane ()

235∘C

255∘C

275∘C





Acknowledgments


References





2





119909

SiO2







2

O3




















1

V025

Nb012Pd00005

O119909



1

V025

Nb012

Pd00005

O119909



V025

Nb012

Pd00005

O119909






























Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of




2





119909

SiO2







2

O3




















1

V025

Nb012Pd00005

O119909



1

V025

Nb012

Pd00005

O119909



V025

Nb012

Pd00005

O119909






























Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of





























Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of

research article revisiting oxidative dehydrogenation of...

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