Synthesis of anisole by vapor phase methylation of phenol with methanol over catalysts supported on activated alumina

Article abstract of DOI:10.1016/S1872-2067(15)61074-9

The synthesis of anisole by vapor phase methylation of phenol with methanol over activated alumina (AA) supported catalysts was investigated in a fixed bed reactor. KH₂PO₄/AA gave the best performance among the eight tested catalysts. The catalyst was prepared by loading KH₂PO₄ on AA and then calcining at the optimized temperature of 700 °C for 8 h. In the vapor phase reaction, the level of anisole yield (LAY) has a maximum at 400-450 °C when the temperature varied from 300 to 500 °C, which decreased slightly with increasing WHSV and increased distinctly with increasing mole fraction of methanol. On comparing O-methylation and C-methylation of phenol, a low temperature, high WHSV (short residence time), and a low methanol concentration over the KH₂PO₄/AA catalyst with higher K contents were found to increase anisole selectivity by O-methylation of phenol. The reaction routes to the major products and the catalytic mechanism were suggested, and a 'K-acid' bifunctional process may be a critical factor to the formation of anisole.

Full text of DOI:10.1016/S1872-2067(15)61074-9

ChineseꢀJournalꢀofꢀCatalysisꢀ37ꢀ(2016)ꢀ720–726
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ꢀ ꢀ ꢀ
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a v a i l a b l e a t w w w . s c i e n c e d i r e c t . c o m
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j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / c h n j c
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Article
Synthesisꢀofꢀanisoleꢀbyꢀvaporꢀphaseꢀmethylationꢀofꢀphenolꢀwithꢀ
methanolꢀoverꢀcatalystsꢀsupportedꢀonꢀactivatedꢀaluminaꢀ
ꢀ
DanꢀDang,ꢀZeꢀWang*,ꢀWeigangꢀLin,ꢀWenliꢀSong
ꢀ
StateꢀKeyꢀLaboratoryꢀofꢀMulti‐PhaseꢀComplexꢀSystems,ꢀInstituteꢀofꢀProcessꢀEngineering,ꢀChineseꢀAcademyꢀofꢀSciences,ꢀBeijingꢀ100190,ꢀChinaꢀ
A R T I C L E ꢀ I N F O ꢀ
A B S T R A C T ꢀ
Articleꢀhistory:ꢀ
Theꢀsynthesisꢀofꢀanisoleꢀbyꢀvaporꢀphaseꢀmethylationꢀofꢀphenolꢀwithꢀmethanolꢀoverꢀactivatedꢀalumi‐
Receivedꢀ19ꢀFebruaryꢀ2016ꢀ
Acceptedꢀ25ꢀFebruaryꢀ2016ꢀ
Publishedꢀ5ꢀMayꢀ2016ꢀ
naꢀ(AA)ꢀsupportedꢀcatalystsꢀwasꢀinvestigatedꢀinꢀaꢀfixedꢀbedꢀreactor.ꢀKH
formanceꢀamongꢀtheꢀeightꢀtestedꢀcatalysts.ꢀTheꢀcatalystꢀwasꢀpreparedꢀbyꢀloadingꢀKH
thenꢀcalciningꢀatꢀtheꢀoptimizedꢀtemperatureꢀofꢀ700ꢀ°Cꢀforꢀ8ꢀh.ꢀInꢀtheꢀvaporꢀphaseꢀreaction,ꢀtheꢀlevelꢀ
ofꢀanisoleꢀyieldꢀ(LAY)ꢀhasꢀaꢀmaximumꢀatꢀ400–450ꢀ°Cꢀwhenꢀtheꢀtemperatureꢀvariedꢀfromꢀ300ꢀtoꢀ500
2
PO
4
/AAꢀgaveꢀtheꢀbestꢀper‐
2
PO ꢀonꢀAAꢀandꢀ
4
°
C,ꢀwhichꢀdecreasedꢀslightlyꢀwithꢀincreasingꢀWHSVꢀandꢀincreasedꢀdistinctlyꢀwithꢀincreasingꢀmoleꢀ
fractionꢀofꢀmethanol.ꢀOnꢀcomparingꢀO‐methylationꢀandꢀC‐methylationꢀofꢀphenol,ꢀaꢀlowꢀtemperature,ꢀ
highꢀWHSVꢀ(shortꢀresidenceꢀtime),ꢀandꢀaꢀlowꢀmethanolꢀconcentrationꢀoverꢀtheꢀKH PO /AAꢀcatalystꢀ
Keywords:ꢀ
Phenolꢀ
Methanolꢀ
Catalysisꢀ
Anisoleꢀ
2
4
withꢀhigherꢀKꢀcontentsꢀwereꢀfoundꢀtoꢀincreaseꢀanisoleꢀselectivityꢀbyꢀO‐methylationꢀofꢀphenol.ꢀTheꢀ
reactionꢀroutesꢀtoꢀtheꢀmajorꢀproductsꢀandꢀtheꢀcatalyticꢀmechanismꢀwereꢀsuggested,ꢀandꢀaꢀ‘K‐acid’ꢀ
bifunctionalꢀprocessꢀmayꢀbeꢀaꢀcriticalꢀfactorꢀtoꢀtheꢀformationꢀofꢀanisole.ꢀ
Methylation
©ꢀ2016,ꢀDalianꢀInstituteꢀofꢀChemicalꢀPhysics,ꢀChineseꢀAcademyꢀofꢀSciences.
PublishedꢀbyꢀElsevierꢀB.V.ꢀAllꢀrightsꢀreserved.
1.ꢀ ꢀ Introductionꢀ
phenolꢀ andꢀ dimethylꢀ carbonateꢀ (DMC)ꢀ hasꢀ beenꢀ investigatedꢀ
[2–5].ꢀDMC,ꢀaꢀgreenꢀchemicalꢀmaterialꢀthatꢀisꢀusedꢀforꢀmethyla‐
Anisoleꢀisꢀanꢀimportantꢀindustrialꢀchemicalꢀandꢀintermedi‐
tion,ꢀ canꢀ beꢀ synthesizedꢀ fromꢀ theꢀ oxidativeꢀ carbonylationꢀ ofꢀ
methanolꢀ[6],ꢀbutꢀtheꢀsynthesisꢀofꢀDMCꢀincreasesꢀtheꢀcomplexi‐
tyꢀandꢀcostꢀofꢀtheꢀanisoleꢀsyntheticꢀprocess.ꢀSo,ꢀanotherꢀmethodꢀ
thatꢀusesꢀmethanolꢀforꢀdirectꢀmethylationꢀtoꢀreplaceꢀDMCꢀwasꢀ
studiedꢀ[1,7–9].ꢀHowever,ꢀinꢀtheꢀreactionꢀbetweenꢀphenolꢀandꢀ
methanol,ꢀ theꢀ productꢀ compositionꢀ isꢀ moreꢀ complicated,ꢀ andꢀ
theꢀ productꢀ fromꢀ O‐methylationꢀ (methylationꢀ onꢀ theꢀ oxygenꢀ
atomꢀofꢀtheꢀphenolicꢀhydroxylꢀgroup)ꢀofꢀphenolꢀisꢀmoreꢀdifficultꢀ
toꢀobtainꢀcomparedꢀtoꢀthatꢀfromꢀC‐methylationꢀ(methylationꢀonꢀ
theꢀcarbonꢀatomꢀofꢀtheꢀaromaticꢀring)ꢀ[10–16].ꢀKirichenkoꢀetꢀal.ꢀ
[1]ꢀobtainedꢀaꢀhighꢀanisoleꢀselectivityꢀofꢀ93.9%ꢀwithꢀaꢀphenolꢀ
conversionꢀ rateꢀ ofꢀ 81%ꢀ withꢀ theꢀ catalysisꢀ ofꢀ NaXꢀ atꢀ 320ꢀ °C.ꢀ
Saralaꢀetꢀal.ꢀ[16]ꢀfoundꢀthatꢀtheꢀexistenceꢀofꢀcesiumꢀinꢀsamari‐
umꢀ phosphateꢀ enhancedꢀ anisoleꢀ selectivityꢀ byꢀ suppressingꢀ
ateꢀ productꢀ usedꢀ forꢀ perfumes,ꢀ flavoringꢀ agents,ꢀ andꢀ organicꢀ
synthesisꢀ[1,2].ꢀAnisoleꢀisꢀusuallyꢀsynthesizedꢀbyꢀaꢀliquidꢀphaseꢀ
processꢀ inꢀ anꢀ alkalineꢀ environment,ꢀ suchꢀ asꢀ theꢀ reactionꢀ be‐
tweenꢀ sodiumꢀ phenolateꢀ andꢀ dimethylꢀ sulfate,ꢀ theꢀ reactionꢀ
betweenꢀ bromobenzeneꢀ andꢀ methanol,ꢀ andꢀ theꢀ reactionꢀ be‐
tweenꢀ sodiumꢀ phenolateꢀ andꢀ chloromethaneꢀ [2].ꢀ However,ꢀ
theseꢀprocessesꢀhaveꢀbeenꢀseverelyꢀrestrictedꢀinꢀrecentꢀyearsꢀ
becauseꢀtheꢀalkaliꢀusedꢀareꢀharmfulꢀtoꢀtheꢀenvironmentꢀandꢀtheꢀ
extremelyꢀ toxicꢀ rawꢀ materialsꢀ likeꢀ dimethylꢀ sulfateꢀ andꢀ bro‐
mobenzeneꢀareꢀdangerousꢀtoꢀhumanꢀhealth.ꢀSo,ꢀaꢀgreenꢀprocessꢀ
forꢀ anisoleꢀ synthesisꢀ isꢀ needed,ꢀ andꢀ aꢀ vaporꢀ phaseꢀ catalyticꢀ
reactionꢀwasꢀproposed.ꢀ ꢀ
Theꢀsynthesisꢀofꢀanisoleꢀbyꢀaꢀvaporꢀphaseꢀreactionꢀbetweenꢀ
*ꢀCorrespondingꢀauthor.ꢀTel:ꢀ+86‐10‐82544963;ꢀFax:ꢀ+86‐10‐82622893;ꢀE‐mail:ꢀwangze@ipe.ac.cnꢀ
ThisꢀworkꢀwasꢀsupportedꢀbyꢀtheꢀNationalꢀNaturalꢀScienceꢀFoundationꢀofꢀChinaꢀ(51476180)ꢀandꢀtheꢀNationalꢀBasicꢀResearchꢀProgramꢀofꢀChinaꢀ(973ꢀ
Program,ꢀ2014CB744304).ꢀ
DOI:ꢀ10.1016/S1872‐2067(15)61074‐9ꢀ|ꢀhttp://www.sciencedirect.com/science/journal/18722067ꢀ|ꢀChin.ꢀJ.ꢀCatal.,ꢀVol.ꢀ37,ꢀNo.ꢀ5,ꢀMayꢀ2016ꢀ ꢀ ꢀ

ꢀ
DanꢀDangꢀetꢀal.ꢀ/ꢀChineseꢀJournalꢀofꢀCatalysisꢀ37ꢀ(2016)ꢀ720–726ꢀ
721ꢀ
C‐alkylatedꢀsideꢀproducts.ꢀAꢀhighꢀanisoleꢀyieldꢀofꢀ83%ꢀwasꢀob‐
tainedꢀatꢀ350ꢀ°C.ꢀGenerally,ꢀcomparedꢀtoꢀtheꢀDMCꢀapproach,ꢀtheꢀ
synthesisꢀ ofꢀ anisoleꢀ fromꢀ theꢀ methylationꢀ ofꢀ phenolꢀ withꢀ
methanolꢀ isꢀ lessꢀ satisfactory,ꢀ andꢀ theꢀ mechanismꢀ isꢀ ratherꢀ
vague.ꢀ Therefore,ꢀ furtherꢀ studyꢀ onꢀ theꢀ vaporꢀ phaseꢀ catalyticꢀ
reactionꢀforꢀanisoleꢀpreparationꢀisꢀofꢀgreatꢀsignificance.ꢀ ꢀ
Inꢀthisꢀpaper,ꢀtheꢀsynthesisꢀofꢀanisoleꢀbyꢀvaporꢀphaseꢀmeth‐
ylationꢀofꢀphenolꢀwithꢀmethanolꢀoverꢀaꢀγ‐Al
2
O ꢀsupportedꢀcata‐
3
lystꢀwasꢀstudied.ꢀTheꢀvaporꢀphaseꢀreactionꢀconditionsꢀofꢀtem‐
perature,ꢀspaceꢀvelocity,ꢀfeedꢀratioꢀofꢀphenolꢀtoꢀmethanol,ꢀandꢀ
catalystꢀ synthesisꢀ conditionsꢀ includingꢀ theꢀ typeꢀ andꢀ loadingꢀ
amountꢀ ofꢀ theꢀ metalꢀ salts,ꢀ andꢀ theꢀ calcinationꢀ temperatureꢀ
wereꢀexaminedꢀforꢀlevelꢀofꢀanisoleꢀyieldꢀoptimization.ꢀAꢀcata‐
lyticꢀmechanismꢀwasꢀdeduced.ꢀ ꢀ
2.ꢀ ꢀ Experimentalꢀ
2.1.ꢀ ꢀ Catalystꢀpreparationꢀ
Fig.ꢀ1.ꢀSchematicꢀofꢀtheꢀlabꢀscaleꢀapparatusꢀforꢀvaporꢀphaseꢀsynthesisꢀofꢀ
anisole.
Theꢀcatalystꢀwasꢀpreparedꢀbyꢀtheꢀimpregnationꢀmethodꢀinꢀ
whichꢀaꢀmetalꢀsaltꢀwasꢀloadedꢀonꢀtheꢀsupportꢀofꢀactivatedꢀalu‐
minaꢀ(AA,ꢀγ‐Al )ꢀgranulesꢀ(diameterꢀaroundꢀ2ꢀmm).ꢀγ‐Al O ꢀ
2.4.ꢀ ꢀ Productꢀanalysisꢀ
O
2 3
2
3
granulesꢀwasꢀwashedꢀwithꢀdistilledꢀwaterꢀandꢀdriedꢀatꢀ120ꢀ°Cꢀ
forꢀ12ꢀhꢀfirst,ꢀandꢀthenꢀcooledꢀtoꢀroomꢀtemperatureꢀforꢀuse.ꢀAꢀ
Toꢀgetꢀtheꢀconversionꢀofꢀphenolꢀandꢀselectivityꢀforꢀanisole,ꢀ
theꢀtotalꢀliquidꢀ inꢀtheꢀtwoꢀbottlesꢀ wereꢀ weighedꢀafterꢀtheꢀex‐
periment.ꢀTheꢀliquidꢀcompositionꢀwasꢀanalyzedꢀbyꢀGC/MSꢀ(gasꢀ
chromatographyꢀcombinedꢀwithꢀmassꢀspectrometry).ꢀTheꢀab‐
soluteꢀamountꢀofꢀphenolꢀremainingꢀinꢀtheꢀliquidꢀproductꢀwasꢀ
determinedꢀbyꢀtheꢀinternalꢀstandardꢀmethod.ꢀTheꢀcompoundꢀofꢀ
isoamylꢀ acetateꢀ(IAA)ꢀ wasꢀusedꢀ asꢀtheꢀinternalꢀ standard.ꢀTheꢀ
conversionꢀofꢀphenolꢀwasꢀdefinedꢀasꢀtheꢀratioꢀofꢀtheꢀmassꢀofꢀ
convertedꢀ phenolꢀ toꢀ theꢀ originalꢀ massꢀ ofꢀ phenolꢀ fedꢀ intoꢀ theꢀ
reactionꢀ system.ꢀ However,ꢀ theꢀ amountsꢀ ofꢀ otherꢀ componentsꢀ
wereꢀnotꢀquantifiedꢀbyꢀtheꢀinternalꢀstandardꢀbecauseꢀtheꢀcor‐
relationꢀwasꢀnotꢀasꢀgoodꢀasꢀthatꢀforꢀphenol.ꢀTherefore,ꢀtheꢀse‐
lectivityꢀofꢀaꢀliquidꢀproductꢀwasꢀdenotedꢀbyꢀitsꢀareaꢀpercentageꢀ
amongꢀ theꢀ majorꢀ products,ꢀ andꢀ accordinglyꢀ theꢀ arithmeticꢀ
productꢀbyꢀmultiplicationꢀbetweenꢀtheꢀphenolꢀconversionꢀrateꢀ
(wt%)ꢀandꢀtheꢀanisoleꢀselectivityꢀ(area%)ꢀwasꢀusedꢀtoꢀrepre‐
sentꢀtheꢀlevelꢀofꢀanisoleꢀyieldꢀ(LAY).ꢀTheꢀanalyticalꢀconditionsꢀ
byꢀ GC/MSꢀ (Varianꢀ 3800GC/300MSꢀ withꢀ FFAPꢀ columnꢀ ofꢀ ꢀ ꢀ ꢀ ꢀ
saltꢀsolutionꢀwasꢀslowlyꢀaddedꢀtoꢀaꢀknownꢀamountꢀofꢀγ‐Al
granulesꢀ accordingꢀ toꢀ theꢀ isopyknicꢀ impregnationꢀ rules.ꢀ Theꢀ
impregnatedꢀγ‐Al ꢀgranulesꢀwereꢀthenꢀplacedꢀinꢀopenꢀairꢀatꢀ
2 3
O ꢀ
O
2 3
roomꢀtemperatureꢀforꢀ24ꢀh,ꢀandꢀfinallyꢀcalcinedꢀinꢀaꢀmuffleꢀfur‐
naceꢀforꢀ8ꢀhꢀ(theꢀcalciningꢀtemperatureꢀwasꢀ700ꢀ°Cꢀunlessꢀoth‐
erwiseꢀspecified).ꢀ ꢀ
2.2.ꢀ ꢀ Catalystꢀcharacterizationꢀ
Theꢀmetalꢀcontentꢀonꢀtheꢀγ‐Al
2
O ꢀsupportꢀwasꢀmeasuredꢀbyꢀ
3
inductivelyꢀ coupledꢀ plasma‐atomicꢀ emissionꢀ spectrometryꢀ
ICP‐AES,ꢀIRISꢀIntrepidꢀIIꢀXSP).ꢀTheꢀchemicalꢀphaseꢀofꢀtheꢀcata‐
lystꢀwasꢀanalyzedꢀbyꢀX‐rayꢀdiffractionꢀ(XRD)ꢀwithꢀaꢀD/teX‐Ultraꢀ
detectorꢀandꢀCuꢀK ꢀradiation.ꢀ ꢀ
(
α
2.3.ꢀ ꢀ Apparatusꢀandꢀprocedureꢀforꢀtheꢀvaporꢀphaseꢀreactionꢀ
25ꢀmmꢀꢀ0.25ꢀmmꢀꢀ0.2ꢀμm)ꢀwereꢀasꢀfollows:ꢀovenꢀtemperatureꢀ
TheꢀschematicꢀofꢀtheꢀexperimentalꢀsystemꢀisꢀshownꢀinꢀFig.ꢀ1.ꢀ
startedꢀfromꢀ40ꢀ°C,ꢀholdꢀforꢀ3ꢀmin,ꢀthenꢀincreasedꢀbyꢀ4ꢀ°C/minꢀ
toꢀ100ꢀ°C,ꢀholdꢀforꢀ3ꢀmin,ꢀandꢀfinallyꢀincreasedꢀtoꢀ240ꢀ°Cꢀbyꢀ6ꢀ
°C/minꢀandꢀholdꢀforꢀ10ꢀmin;ꢀtheꢀinjectorꢀtemperatureꢀwasꢀ240ꢀ
°Cꢀandꢀtheꢀionꢀsourceꢀtemperatureꢀwasꢀ250ꢀ°C.ꢀTheꢀerrorꢀanaly‐
sisꢀofꢀtheꢀexperimentalꢀsystemꢀwasꢀconductedꢀbyꢀthreeꢀrepeat‐
edꢀexperiments.ꢀTheꢀstandardꢀdeviationꢀofꢀphenolꢀconversionꢀ
rateꢀ wasꢀ 1.88%.ꢀ Theꢀ standardꢀ deviationꢀ ofꢀ anisoleꢀ selectivityꢀ
wasꢀ0.42%.ꢀ ꢀ ꢀ
Theꢀ liquidꢀ reactantꢀ mixtureꢀ ofꢀ phenolꢀ andꢀ methanolꢀ andꢀ aꢀ
streamꢀofꢀnitrogenꢀasꢀcarrierꢀgasꢀwereꢀintroducedꢀintoꢀaꢀfixedꢀ
bedꢀreactorꢀbyꢀaꢀperistalticꢀpumpꢀandꢀmassꢀflowmeter,ꢀrespec‐
tively.ꢀTheꢀfixedꢀbedꢀreactorꢀwasꢀaꢀquartzꢀtubeꢀ(lengthꢀofꢀ600ꢀ
mmꢀandꢀinnerꢀdiameterꢀofꢀ27ꢀmm)ꢀplacedꢀcoaxiallyꢀinꢀanꢀelec‐
tricꢀ furnace.ꢀ Aboutꢀ 20ꢀ gꢀ catalystꢀ granulesꢀ wereꢀ loadedꢀ insideꢀ
theꢀreactor.ꢀWhenꢀtheꢀsetꢀtemperatureꢀwasꢀreached,ꢀtheꢀcarrierꢀ
gasꢀofꢀnitrogenꢀ(100ꢀmL/min)ꢀwasꢀintroducedꢀintoꢀtheꢀreactorꢀ
toꢀ purgeꢀ outꢀ air.ꢀ Thenꢀ theꢀ liquidꢀ reactantsꢀ wereꢀ fedꢀ intoꢀ theꢀ
reactor.ꢀTheꢀproductsꢀwereꢀtakenꢀoutꢀofꢀtheꢀreactorꢀandꢀsentꢀtoꢀ
aꢀcondensingꢀunit,ꢀwhichꢀcomprisedꢀaꢀGrahamꢀcondenserꢀandꢀ
twoꢀbottlesꢀlocatedꢀinꢀanꢀice‐waterꢀbath.ꢀTheꢀproductꢀwasꢀcon‐
densedꢀtoꢀliquidꢀandꢀcollectedꢀinꢀtheꢀbottles.ꢀInꢀeachꢀrun,ꢀtheꢀ
timeꢀonꢀstreamꢀwasꢀ3ꢀh.ꢀ ꢀ
3.ꢀ ꢀ Resultsꢀandꢀdiscussionꢀ
3.1.ꢀ ꢀ Catalystꢀpreparationꢀconditionsꢀ
3.1.1.ꢀ ꢀ Influenceꢀofꢀtheꢀtypeꢀofꢀmetalꢀsaltꢀonꢀcatalystꢀ ꢀ
performanceꢀ

722ꢀ
DanꢀDangꢀetꢀal.ꢀ/ꢀChineseꢀJournalꢀofꢀCatalysisꢀ37ꢀ(2016)ꢀ720–726ꢀ
Tableꢀ1ꢀ
Catalyticꢀperformanceꢀdueꢀtoꢀtheꢀtypeꢀofꢀmetalꢀsaltꢀimpregnatedꢀinꢀγ‐Al
2
O .ꢀ
3
Metalꢀcontentꢀ ꢀ
Phenolꢀconversionꢀ ꢀ
(wt%)ꢀ
Selectivityꢀ(area%)ꢀ
Saltꢀ
(wt%)ꢀ
Anisoleꢀ
—ꢀ
27.68ꢀ
90.04ꢀ
—ꢀ
—ꢀ
ꢀ 0.62ꢀ
—ꢀ
Methylꢀanisoleꢀ
BTXꢀ
45.01ꢀ
—ꢀ
Methylꢀphenolꢀ
Othersꢀ
42.52ꢀ
ꢀ 0.91ꢀ
ꢀ 5.81ꢀ
35.87ꢀ
19.85ꢀ
ꢀ 9.77ꢀ
31.49ꢀ
21.77ꢀ
18.27ꢀ
Noneꢀ
NaClꢀ
0ꢀ
100ꢀ
ꢀ ꢀ ꢀ ꢀ 72.76ꢀ
ꢀ ꢀ ꢀ ꢀ 75.12ꢀ
ꢀ ꢀ ꢀ ꢀ 97.94ꢀ
100ꢀ
—ꢀ
6.58ꢀ
2.13ꢀ
—ꢀ
—ꢀ
—ꢀ
—ꢀ
3.10ꢀ
—ꢀ
12.47ꢀ
64.73ꢀ
ꢀ 2.02ꢀ
23.82ꢀ
60.92ꢀ
49.03ꢀ
28.11ꢀ
58.64ꢀ
59.97ꢀ
5.23ꢀ
4.44ꢀ
1.11ꢀ
3.20ꢀ
7.47ꢀ
6.76ꢀ
1.45ꢀ
2.55ꢀ
KH
MgCl
Fe (SO
Co(NO
ZnCl
La(NO
Ce(NO
2
PO
4
ꢀ
—ꢀ
2
ꢀ
40.31ꢀ
19.24ꢀ
40.58ꢀ
40.40ꢀ
16.49ꢀ
20.98ꢀ
2
4
)
3
ꢀ
ꢀ
3
)
2
100ꢀ
100ꢀ
100ꢀ
2
ꢀ
3
)
3
ꢀ
—ꢀ
3
)
3
ꢀ
100ꢀ
ꢀ 0.78ꢀ
BTX:ꢀBenzene‐toluene‐xylene.ꢀ
ꢀ
Theꢀ typeꢀ ofꢀ metalꢀ saltꢀ impregnatedꢀ onꢀ theꢀ Al
wasꢀfirstꢀinvestigatedꢀunderꢀreactionꢀconditionsꢀofꢀaꢀtempera‐
tureꢀofꢀ400ꢀ°C,ꢀweightꢀhourlyꢀspaceꢀvelocityꢀ(WHSV)ꢀofꢀ0.21ꢀh ,ꢀ
andꢀmoleꢀratioꢀofꢀphenolꢀtoꢀmethanolꢀofꢀ1:5.ꢀTableꢀ1ꢀsumma‐
rizesꢀtheꢀconversionꢀofꢀphenolꢀandꢀselectivitiesꢀforꢀsomeꢀmainꢀ
productꢀ components.ꢀ Theꢀ metalꢀ contentꢀ wasꢀ obtainedꢀ fromꢀ
2
O
3
ꢀ supportꢀ
soleꢀ selectivityꢀ andꢀ significantꢀ changeꢀ ofꢀ phenolꢀ conversionꢀ
gaveꢀaꢀsimilarꢀtrendꢀofꢀLAYꢀtoꢀthatꢀofꢀphenolꢀconversionꢀwithꢀ
increasingꢀ calcinationꢀ temperature.ꢀ Aꢀ highestꢀ LAYꢀ ofꢀ 70.92%ꢀ
appearedꢀatꢀ700ꢀ°Cꢀasꢀwell.ꢀ
–1
XRDꢀ analysisꢀ ofꢀ KH
turesꢀareꢀshownꢀinꢀFig.ꢀ3.ꢀItꢀcanꢀbeꢀseenꢀthatꢀaꢀnewꢀchemicalꢀ
phaseꢀofꢀK Al (PO 3ꢀwasꢀgeneratedꢀonꢀtheꢀγ‐Al ꢀsupport.ꢀInꢀ
particular,ꢀtheꢀpeakꢀintensityꢀofꢀK Al (PO 3ꢀwasꢀmoreꢀdistinctꢀ
2 4
PO /AAꢀ calcinedꢀatꢀdifferentꢀtempera‐
ICP‐AESꢀanalysis.ꢀItꢀcanꢀbeꢀseenꢀfromꢀTableꢀ1ꢀthatꢀKH
enhancedꢀbothꢀphenolꢀconversionꢀandꢀanisoleꢀselectivity.ꢀSo,ꢀinꢀ
2 4
PO /AAꢀ
3
2
4
)
O
2 3
3
2
4
)
theꢀ followingꢀ work,ꢀ theꢀ catalystꢀ ofꢀ KH
furtherꢀinvestigation.ꢀ ꢀ ꢀ
2 4
PO /AAꢀ wasꢀ usedꢀ forꢀ
atꢀtheꢀcalcinationꢀtemperatureꢀofꢀ600ꢀandꢀ800ꢀ°C,ꢀwhichꢀwasꢀ
oppositeꢀtoꢀtheꢀbetterꢀperformancesꢀofꢀtheꢀcatalystsꢀcalcinedꢀatꢀ
5
00ꢀandꢀ700ꢀ°Cꢀonꢀtheꢀphenolꢀconversion.ꢀThisꢀindicatedꢀthatꢀ
tooꢀmuchꢀK Al (PO ꢀgeneratedꢀwasꢀdisadvantageousꢀforꢀtheꢀ
catalystꢀactivity.ꢀ ꢀ ꢀ ꢀ ꢀ
3
.1.2.ꢀ ꢀ Influenceꢀofꢀcalcinationꢀtemperatureꢀonꢀtheꢀperformanceꢀ
ofꢀKH PO /AAꢀ
Theꢀ effectꢀ ofꢀ calcinationꢀ temperatureꢀ onꢀ theꢀ catalyticꢀ per‐
formanceꢀofꢀKH PO /AAꢀ(Kꢀcontentꢀofꢀ8.75ꢀwt%)ꢀisꢀshownꢀinꢀ
3
2
)
4 3
2
4
2
4
3.1.3.ꢀ ꢀ EffectꢀofꢀKꢀcontentꢀonꢀtheꢀperformanceꢀofꢀKH
Underꢀtheꢀsameꢀreactionꢀconditionsꢀgivenꢀabove,ꢀtheꢀeffectꢀ
ofꢀ Kꢀ contentꢀ onꢀ theꢀ performanceꢀ ofꢀ KH PO /AAꢀ wasꢀ investi‐
2 4
PO /AAꢀ
Fig.ꢀ2.ꢀTheꢀvaporꢀphaseꢀreactionꢀwasꢀconductedꢀunderꢀtheꢀsameꢀ
conditionsꢀasꢀgivenꢀbefore.ꢀItꢀcanꢀbeꢀseenꢀthatꢀtheꢀphenolꢀcon‐
versionꢀwasꢀhigherꢀatꢀtheꢀcalcinationꢀtemperaturesꢀofꢀ500ꢀandꢀ
2
4
gatedꢀasꢀshownꢀinꢀFig.ꢀ4.ꢀItꢀcanꢀbeꢀseenꢀthatꢀtheꢀphenolꢀconver‐
sionꢀgenerallyꢀdecreasedꢀwithꢀincreasingꢀKꢀcontentꢀandꢀinꢀpar‐
ticularꢀ decreasedꢀ fasterꢀ withꢀ Kꢀ contentꢀ ofꢀ overꢀ 7.53ꢀ wt%.ꢀ Inꢀ
contrast,ꢀtheꢀselectivityꢀtoꢀanisoleꢀincreasedꢀrapidlyꢀwithꢀaꢀlowꢀ
Kꢀ contentꢀ andꢀ becameꢀ stableꢀ withꢀ increasingꢀ Kꢀ contentꢀ afterꢀ
4.44ꢀwt%.ꢀTheꢀselectivitiesꢀofꢀtheꢀotherꢀcomponentsꢀexhibitedꢀaꢀ
7
00ꢀ°C,ꢀandꢀreachedꢀtheꢀhighestꢀvalueꢀofꢀ72.34%ꢀatꢀ700ꢀ°C.ꢀAn‐
isoleꢀisꢀtheꢀmainꢀproductꢀandꢀtheꢀotherꢀproductsꢀwereꢀmethyl‐
anisole,ꢀmethylphenol,ꢀandꢀdimethylphenol,ꢀwithꢀaꢀhighꢀanisoleꢀ
selectivityꢀofꢀoverꢀ98%.ꢀTheꢀselectivityꢀtoꢀanisoleꢀvariedꢀslightlyꢀ
inꢀaꢀreverseꢀtrendꢀtoꢀthatꢀofꢀmethylanisole.ꢀThisꢀindicatedꢀthatꢀ
theꢀconsecutiveꢀconversionꢀofꢀanisoleꢀtoꢀmethylanisoleꢀisꢀaꢀma‐
jorꢀcauseꢀofꢀtheꢀdecreaseꢀofꢀanisole.ꢀTheꢀslightꢀvariationꢀofꢀani‐
★
★
★
K3Al2(PO
4
)3
2 3
Al O
o
1
00
100
80
500 C
9
9
9
9
9
8
6
4
2
0
★★
★
★
★
Phenol conversion
Level of anisole yield
★
o
6
00 C
60
★★
★
★
Anisole
4
0
4
3
2
1
0
o
Methylanisole
Methylphenol
Dimethylphenol
700 C
★
★
★
★
★
20
0
★
o
8
00 C
500
600
700
o
800
20
40
60
80
Temprature ( C)
o
2
/( )
Fig.ꢀ 2.ꢀ Effectꢀ ofꢀ calcinationꢀ temperatureꢀ onꢀ theꢀ performanceꢀ of
KH PO /AA.ꢀ
Fig.ꢀ 3.ꢀ XRDꢀ patternsꢀ ofꢀ KH
tures.ꢀ
2 4
PO /AAꢀ atꢀ differentꢀ calcinationꢀ tempera‐
2
4

ꢀ
DanꢀDangꢀetꢀal.ꢀ/ꢀChineseꢀJournalꢀofꢀCatalysisꢀ37ꢀ(2016)ꢀ720–726ꢀ
723ꢀ
WHSV,ꢀandꢀmolarꢀratioꢀofꢀphenolꢀtoꢀmethanolꢀonꢀtheꢀconver‐
sionꢀofꢀphenol,ꢀselectivityꢀtoꢀanisole,ꢀandꢀlevelꢀofꢀanisoleꢀyieldꢀ
wereꢀinvestigated.ꢀ ꢀ
1
00
100
80
60
40
20
0
Phenol conversion
Level of anisole yield
8
6
4
2
0
0
0
0
0
3.2.1.ꢀ ꢀ Influenceꢀofꢀtemperatureꢀ
Fig.ꢀ6ꢀ showsꢀtheꢀinfluenceꢀofꢀreactionꢀtemperatureꢀonꢀtheꢀ
performanceꢀofꢀKH
2
PO /AAꢀ(Kꢀcontentꢀ7.72ꢀwt%).ꢀTheꢀreactionꢀ
4
Anisole
wasꢀconductedꢀatꢀtemperaturesꢀfromꢀ300ꢀtoꢀ500ꢀ°Cꢀwithꢀaꢀcon‐
Methylanisole
Methylphenol
Dimethylphenol
stantꢀWHSVꢀofꢀ0.21ꢀh ꢀandꢀmoleꢀratioꢀofꢀphenolꢀtoꢀmethanolꢀofꢀ
:5.ꢀItꢀcanꢀbeꢀseenꢀthatꢀtheꢀphenolꢀconversionꢀincreasedꢀwithꢀ
–1
1
increasingꢀ temperatureꢀ fromꢀ 300ꢀ toꢀ 500ꢀ °C.ꢀ Anisoleꢀ wasꢀ theꢀ
mainꢀproductꢀatꢀlowꢀtemperatures,ꢀandꢀitsꢀamountꢀdecreasedꢀ
slowlyꢀwithꢀincreasingꢀtemperatureꢀandꢀdecreasedꢀmuchꢀfasterꢀ
atꢀhighꢀtemperaturesꢀoverꢀ450ꢀ°C.ꢀTheꢀselectivitiesꢀofꢀtheꢀotherꢀ
threeꢀcomponentsꢀincreasedꢀwithꢀincreasingꢀtemperature,ꢀandꢀ
inꢀ particular,ꢀ theꢀ formationꢀ ofꢀ methylphenolꢀ wasꢀ promotedꢀ
mostꢀ significantlyꢀ atꢀ highꢀ temperatures.ꢀ Thisꢀ indicatedꢀ thatꢀ aꢀ
lowꢀtemperatureꢀfavoredꢀtheꢀO‐methylationꢀofꢀphenol,ꢀandꢀtheꢀ
C‐methylationꢀ ofꢀ phenolꢀ wasꢀ prevalentꢀ atꢀ highꢀ temperatures.ꢀ
Asꢀ theꢀ arithmeticꢀ productꢀ ofꢀ phenolꢀ conversionꢀ andꢀ anisoleꢀ
selectivity,ꢀtheꢀLAYꢀreachedꢀtheꢀhighestꢀvalueꢀofꢀ77.5%ꢀatꢀtheꢀ
temperatureꢀ ofꢀ 400–450ꢀ °C,ꢀ indicatingꢀ anꢀ optimalꢀ operatingꢀ
temperatureꢀrange.ꢀ
3
6
9
12
15
18
K content (wt%)
Fig.ꢀ4.ꢀEffectꢀofꢀKꢀcontentꢀonꢀtheꢀperformanceꢀofꢀKH
2
4
PO /AA.ꢀ
commonꢀreverseꢀtrendꢀtoꢀthatꢀofꢀanisole.ꢀInꢀparticular,ꢀtheꢀse‐
lectivityꢀofꢀmethyphenolꢀwasꢀtheꢀhighestꢀandꢀevenꢀhigherꢀthanꢀ
thatꢀofꢀanisoleꢀatꢀtheꢀlowestꢀKꢀcontent.ꢀThisꢀindicatedꢀthatꢀaꢀlowꢀ
Kꢀ contentꢀ wasꢀ advantageousꢀ forꢀ C‐methylationꢀ conversionꢀ ofꢀ
phenol,ꢀ whileꢀ aꢀ highꢀ contentꢀ ofꢀ Kꢀ favoredꢀ theꢀ conversionꢀ ofꢀ
phenolꢀ byꢀ O‐methylation,ꢀ illustratingꢀ theꢀ importanceꢀ ofꢀ Kꢀ onꢀ
theꢀ formationꢀ ofꢀ anisole.ꢀ Byꢀ multiplicationꢀ betweenꢀ theꢀ twoꢀ
factorsꢀofꢀconversionꢀandꢀselectivityꢀofꢀanisole,ꢀtheꢀLAYꢀreachedꢀ
theꢀhighestꢀofꢀ80.06%ꢀatꢀtheꢀKꢀcontentꢀofꢀ7.53ꢀwt%.ꢀ ꢀ
3.2.2.ꢀ ꢀ InfluenceꢀofꢀWHSVꢀ
TheꢀKH
alyzedꢀbyꢀXRD,ꢀasꢀshownꢀinꢀFig.ꢀ5.ꢀItꢀcanꢀbeꢀseenꢀthatꢀonlyꢀtheꢀ
peaksꢀ ofꢀ Al ꢀ couldꢀ beꢀ detectedꢀ onꢀ theꢀ catalystsꢀ withꢀ lowꢀ Kꢀ
contents.ꢀForꢀtheꢀcatalystsꢀwithꢀKꢀcontentsꢀatꢀ7.53–12.48ꢀwt%,ꢀ
theꢀpeaksꢀofꢀAl ꢀwereꢀreducedꢀandꢀsimultaneouslyꢀtheꢀpeaksꢀ
ofꢀK Al (PO 3ꢀappearedꢀdistinctlyꢀwithꢀincreasingꢀKꢀcontent.ꢀByꢀ
consideringꢀtheꢀperformanceꢀofꢀtheꢀcatalyst,ꢀtheꢀmiddleꢀvalueꢀofꢀ
.53ꢀwt%ꢀwasꢀtheꢀoptimumꢀKꢀcontentꢀforꢀtheꢀhighestꢀselectivityꢀ
toꢀanisole.ꢀ ꢀ ꢀ ꢀ
2
PO
4
/AAꢀcatalystsꢀwithꢀdifferentꢀKꢀloadingsꢀwereꢀan‐
TheꢀinfluenceꢀofꢀWHSVꢀonꢀtheꢀperformanceꢀofꢀKH
2
PO /AAꢀ
4
(Kꢀcontentꢀ8.45ꢀwt%)ꢀwasꢀinvestigatedꢀasꢀshownꢀinꢀFig.ꢀ7.ꢀTheꢀ
reactionꢀ wasꢀ conductedꢀ underꢀ differentꢀ WHSVs,ꢀ whichꢀ wereꢀ
controlledꢀ byꢀ aꢀ variedꢀ feedingꢀ rateꢀ ofꢀ theꢀ reactantꢀ mixture,ꢀ
whileꢀtheꢀotherꢀconditionsꢀwereꢀconstantꢀatꢀ400ꢀ°Cꢀandꢀmoleꢀ
ratioꢀofꢀphenolꢀtoꢀmethanolꢀofꢀ1:5.ꢀItꢀcanꢀbeꢀseenꢀthatꢀphenolꢀ
conversionꢀdecreasedꢀwithꢀincreasingꢀWHSV.ꢀAnisoleꢀselectivi‐
tyꢀincreasedꢀslightlyꢀwithꢀtheꢀincreaseꢀofꢀWHSV,ꢀwhileꢀtheꢀotherꢀ
productsꢀslightlyꢀdecreased.ꢀThisꢀindicatedꢀthatꢀanisoleꢀwasꢀaꢀ
primaryꢀ product,ꢀ andꢀ thusꢀ aꢀ shorterꢀ residenceꢀ timeꢀ wasꢀ ad‐
vantageousꢀ forꢀ aꢀ higherꢀ selectivityꢀ toꢀ anisole.ꢀ Theꢀ decreasedꢀ
phenolꢀ conversionꢀ andꢀ theꢀ slightlyꢀ variedꢀ anisoleꢀ selectivityꢀ
determinedꢀaꢀdecreasingꢀtrendꢀofꢀLAYꢀwithꢀaꢀsimilarꢀtrendꢀtoꢀ
thatꢀ ofꢀ phenolꢀ conversionꢀ withꢀ increasingꢀ WHSV,ꢀ andꢀ aꢀ highꢀ
O
2 3
O
2 3
3
2
4
)
7
3.2.ꢀ ꢀ Influenceꢀofꢀvaporꢀphaseꢀreactionꢀconditionsꢀonꢀtheꢀ ꢀ
performanceꢀofꢀKH PO /AAꢀ
2
4
Underꢀ theꢀ catalysisꢀ ofꢀ KH
2
PO /AA,ꢀ theꢀ influenceꢀ ofꢀ vaporꢀ
4
–1
phaseꢀreactionꢀconditionsꢀincludingꢀtheꢀreactionꢀtemperature,ꢀ
LAYꢀoverꢀ70%ꢀwasꢀobtainedꢀatꢀaꢀlowꢀWHSVꢀlessꢀthanꢀ0.18ꢀh .ꢀ
Al O
100
100
80
60
40
20
0
2
3

-Al O
★
K Al (PO )
2 3
Phenol conversion
Level of anisole yield
3
2
4 3
80
60
40
2
.00 wt%
4
.44 wt%
Anisole
Methylanisole
Methylphenol
Dimethylphenol
7
.53 wt%
★
★★
20
0
★
★
★
9
.82 wt%
★
★★
★
1
2.48 wt%
300
350
400
450
500
o
2
0
40
60
80
Temperature ( C)
o
2
 /( )
Fig.ꢀ 6.ꢀ Effectꢀ ofꢀ reactionꢀ temperatureꢀ onꢀ theꢀ performanceꢀ ofꢀ
Fig.ꢀ5.ꢀXRDꢀpatternsꢀofꢀKH
2
PO /AAꢀwithꢀdifferentꢀKꢀcontents.ꢀ
4
KH PO /AA.ꢀ
2
4

724ꢀ
DanꢀDangꢀetꢀal.ꢀ/ꢀChineseꢀJournalꢀofꢀCatalysisꢀ37ꢀ(2016)ꢀ720–726ꢀ
OH
OH
1
00
100
80
CH
3
H
3
C
CH
3
C-Methylation
(d)
Phenol conversion
Level of anisole yield
9
0
0
OH
8
60
Anisole
Methylanisole
Methylphenol
(e)
OCH
3
OCH
3
40
CH
3
Dimethylphenol
(c)
5
C-Methylation
20
Fig.ꢀ9.ꢀReactionsꢀroutesꢀtoꢀtheꢀmajorꢀproducts.ꢀ
0
0
0
.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40
1
3.3.ꢀ ꢀ Reactionsꢀroutesꢀtoꢀtheꢀmajorꢀproductsꢀ ꢀ
WHSV (h )
Fig.ꢀ7.ꢀEffectꢀofꢀWHSVꢀonꢀtheꢀperformanceꢀofꢀKH
2
PO
4
/AA.ꢀ
PhenolꢀcanꢀbeꢀconvertedꢀtoꢀarylꢀethersꢀbyꢀO‐methylationꢀorꢀ
toꢀ methylꢀ phenolsꢀ byꢀ C‐methylationꢀ overꢀ differentꢀ catalystsꢀ
underꢀdifferentꢀconditions.ꢀAꢀsummaryꢀofꢀtheꢀaboveꢀresultsꢀisꢀ
thatꢀaꢀlowꢀreactionꢀtemperature,ꢀhighꢀWHSVꢀmeaningꢀaꢀshorterꢀ
AnꢀevenꢀlowerꢀWHSVꢀwillꢀcauseꢀanꢀevenꢀlongerꢀresidenceꢀtimeꢀ
andꢀthusꢀreducingꢀtheꢀtimeꢀefficiencyꢀofꢀtheꢀprocess,ꢀthoughꢀitꢀ
favorsꢀtheꢀincreaseꢀofꢀLAYꢀfurther.ꢀSo,ꢀaꢀpreferredꢀWHSVꢀshouldꢀ
beꢀ determinedꢀ byꢀ optimizingꢀ betweenꢀ anisoleꢀ yieldꢀ andꢀ timeꢀ
efficiency.ꢀ ꢀ ꢀ ꢀ
residenceꢀ time,ꢀ andꢀ lowꢀ methanolꢀ fractionꢀ overꢀ KH
2
PO /AAꢀ
4
withꢀaꢀhigherꢀKꢀcontentꢀfavoredꢀtheꢀincreaseꢀofꢀanisoleꢀselectiv‐
ityꢀbyꢀO‐methylationꢀofꢀphenol.ꢀRelatively,ꢀtheꢀreactionꢀtemper‐
atureꢀandꢀKꢀcontentꢀofꢀtheꢀcatalystꢀwereꢀtheꢀmoreꢀsignificantꢀ
influencingꢀfactors.ꢀ ꢀ
3
.2.3.ꢀ ꢀ Influenceꢀofꢀreactantꢀcompositionꢀ
Accordingꢀ toꢀ theꢀ aboveꢀ results,ꢀ theꢀ reactionꢀ routesꢀ toꢀ theꢀ
majorꢀproductsꢀcanꢀbeꢀdeduced.ꢀAsꢀshownꢀinꢀFig.ꢀ9,ꢀphenolꢀisꢀ
firstꢀconvertedꢀtoꢀanisoleꢀbyꢀO‐methylationꢀandꢀtoꢀmethylphe‐
nolꢀbyꢀC‐methylationꢀinꢀparallel.ꢀRouteꢀ(a)ꢀisꢀtheꢀdominantꢀoneꢀ
underꢀ theꢀ optimizedꢀ reactionꢀ conditionsꢀ asꢀ discussedꢀ above.ꢀ
Theꢀobtainedꢀmethylphenolꢀandꢀanisoleꢀareꢀfurtherꢀconvertedꢀ
toꢀ dimethylphenolꢀ andꢀ methylanisoleꢀ byꢀ C‐methylation.ꢀ
Methylanisoleꢀ mayꢀ alsoꢀ beꢀ generatedꢀ fromꢀ methylphenolꢀ byꢀ
routeꢀ(e)ꢀbeyondꢀrouteꢀ(c),ꢀwhileꢀrouteꢀ(c)ꢀwouldꢀbeꢀtheꢀpre‐
ferredꢀoneꢀforꢀtheꢀformationꢀofꢀmethylanisoleꢀsinceꢀtheꢀamountꢀ
ofꢀanisoleꢀwasꢀmuchꢀhigherꢀthanꢀthatꢀofꢀmethylphenol.ꢀ ꢀ
Fig.ꢀ8ꢀdisplaysꢀtheꢀeffectꢀofꢀreactantꢀcompositionꢀonꢀtheꢀper‐
formanceꢀ ofꢀ KH
2
PO /AAꢀ (Kꢀ contentꢀ 7.34ꢀ wt%).ꢀ Theꢀ reactionꢀ
4
wasꢀconductedꢀunderꢀaꢀvariedꢀmolarꢀratioꢀofꢀphenolꢀtoꢀmetha‐
nolꢀwithꢀaꢀconstantꢀtemperatureꢀofꢀ400ꢀ°CꢀandꢀaꢀWHSVꢀofꢀ0.21ꢀ
–1
h .ꢀItꢀcanꢀbeꢀseenꢀthatꢀphenolꢀconversionꢀincreasedꢀdistinctlyꢀ
withꢀincreasingꢀmoleꢀfractionꢀofꢀmethanol.ꢀTheꢀselectivitiesꢀofꢀ
allꢀ products,ꢀ includingꢀ theꢀ mainꢀ productꢀ ofꢀ anisole,ꢀ generallyꢀ
variedꢀveryꢀlittleꢀwithꢀtheꢀincreaseꢀofꢀmoleꢀfractionꢀofꢀmethanol.ꢀ
Aꢀ lowꢀ methanolꢀ fractionꢀ favoredꢀ highꢀ anisoleꢀ selectivity.ꢀ LAYꢀ
increasedꢀwithꢀincreasingꢀmethanolꢀfractionꢀinꢀaꢀsimilarꢀtrendꢀ
toꢀ thatꢀ ofꢀ phenolꢀ conversion,ꢀ andꢀ aꢀ highꢀ LAYꢀ overꢀ 80%ꢀ wasꢀ
obtainedꢀwhenꢀtheꢀmethanolꢀfractionꢀwasꢀ5ꢀtimesꢀhigherꢀthanꢀ
theꢀphenolꢀfraction.ꢀTheꢀreactionꢀbetweenꢀphenolꢀandꢀmethanolꢀ
toꢀ anisoleꢀ isꢀ aꢀ processꢀ withꢀ equalꢀ stoichiometricꢀ coefficients,ꢀ
andꢀthusꢀanꢀexcessꢀofꢀmethanolꢀcanꢀpromoteꢀtheꢀreactionꢀinꢀtheꢀ
forwardꢀdirection.ꢀ ꢀ
3.4.ꢀ ꢀ Catalyticꢀmechanismꢀ
Basedꢀonꢀtheꢀresultsꢀgivenꢀabove,ꢀtheꢀreactionꢀmechanismꢀ
overꢀKH
2
PO /AAꢀwasꢀdeducedꢀandꢀshownꢀinꢀFig.ꢀ10.ꢀInꢀtheꢀva‐
4
porꢀphaseꢀreaction,ꢀphenolꢀwasꢀadsorbedꢀonꢀtheꢀKꢀsitesꢀofꢀtheꢀ
catalystꢀsurface.ꢀMethanolꢀwasꢀadsorbedꢀonꢀtheꢀLewisꢀacidꢀsitesꢀ
ofꢀalumina.ꢀTheꢀanionꢀofꢀ OHꢀwasꢀremovedꢀfromꢀmethanolꢀbyꢀ
1
00
100
80
60
40
20
0
–
theꢀacidicꢀalumina,ꢀgeneratingꢀaꢀseparatedꢀcationꢀofꢀCH
presenceꢀofꢀK,ꢀtheꢀH ꢀcationꢀofꢀphenolꢀwasꢀreplacedꢀbyꢀtheꢀK ꢀ
3
+.ꢀInꢀtheꢀ
Phenol conversion
Level of anisol yield
8
6
4
2
0
0
0
0
0
+
+
CH
3
3
H C
O
O
H
O
O
H
H
H
O
K
O
Al
O
O
K
O
Cat.
Al
O
Anisole
Methylanisole
Methylphenol
Dimethylphenol
Cat.
CH
3
1:1
1:2
1:3
1:4
1:5
CH
3
O
O
H
O
O
H
H
H
Molar ratio of phenol to methanol
O
K
O
Al
O
O
K
O
Al
O
Cat.
Cat.
Fig.ꢀ8.ꢀEffectꢀofꢀmoleꢀratioꢀofꢀphenolꢀtoꢀmethanolꢀonꢀtheꢀperformanceꢀof
KH PO /AA.ꢀ
Fig.ꢀ10.ꢀCatalyticꢀmechanismꢀforꢀtheꢀvaporꢀphaseꢀmethylationꢀofꢀphenolꢀ
withꢀmethanolꢀoverꢀKH PO /AA.ꢀ
2
4
2
4

ꢀ
DanꢀDangꢀetꢀal.ꢀ/ꢀChineseꢀJournalꢀofꢀCatalysisꢀ37ꢀ(2016)ꢀ720–726ꢀ
725ꢀ
+
–
cationꢀofꢀtheꢀcatalyst.ꢀCH
3
ꢀfromꢀmethanolꢀandꢀtheꢀPh–O ꢀfromꢀ
phenolꢀgaveꢀanisole.ꢀ ꢀ
phenolꢀthenꢀcombinedꢀtoꢀgiveꢀanisole,ꢀandꢀwaterꢀwasꢀalsoꢀgen‐
+
–
eratedꢀ byꢀ theꢀ combinationꢀ ofꢀ H ꢀ andꢀ OH.ꢀ So,ꢀ theꢀ catalyticꢀ
mechanismꢀcanꢀbeꢀattributedꢀtoꢀaꢀ‘K‐acid’ꢀbifunctionalꢀprocess.ꢀ
Accordingꢀ toꢀ thisꢀ mechanism,ꢀ anꢀ excessꢀ ofꢀ Kꢀ canꢀ occupyꢀ theꢀ
Lewisꢀacidꢀsites,ꢀandꢀthusꢀdecreaseꢀtheꢀactivationꢀofꢀmethanol,ꢀ
whileꢀaꢀlowꢀKꢀloadingꢀwouldꢀgiveꢀdecreasedꢀactivationꢀofꢀphe‐
nol.ꢀ Thisꢀ explainsꢀ theꢀ phenomenonꢀ thatꢀ theꢀ catalystꢀ withꢀ theꢀ
bestꢀperformanceꢀhasꢀaꢀmediumꢀloading.ꢀ ꢀ
Referencesꢀ
[1] G.ꢀ N.ꢀ Kirichenko,ꢀ V.ꢀ I.ꢀ Glazunova,ꢀ A.ꢀ V.ꢀ Balaev,ꢀ U.ꢀ M.ꢀ Dzhemilev,ꢀ
Petrol.ꢀChem.,ꢀ2008,ꢀ48,ꢀ389–392.ꢀ
[
[
[
2] X.ꢀJ.ꢀSong,ꢀC.ꢀS.ꢀWang,ꢀFineꢀChem.,ꢀ2000,ꢀ17,ꢀ42–44.ꢀ
3] Z.ꢀH.ꢀFu,ꢀY.ꢀOno,ꢀCatal.ꢀLett.,ꢀ1993,ꢀ21,ꢀ43–47.ꢀ
4] S.ꢀOuk,ꢀS.ꢀThiebaud,ꢀE.ꢀBorredon,ꢀP.ꢀLeꢀGars,ꢀGreenꢀChem.,ꢀ2002,ꢀ4,ꢀ
431–435.ꢀ
[5] G.ꢀD.ꢀWu,ꢀX.ꢀL.ꢀWang,ꢀB.ꢀChen,ꢀJ.ꢀP.ꢀLi,ꢀN.ꢀZhao,ꢀW.ꢀWei,ꢀY.ꢀH.ꢀSun,ꢀ
Appl.ꢀCatal.ꢀA,ꢀ2007,ꢀ329,ꢀ106–111.ꢀ
4.ꢀ ꢀ Conclusionsꢀ
[
6] Y.ꢀOno,ꢀCatal.ꢀToday,ꢀ1997,ꢀ35,ꢀ15–25.ꢀ
7] M.ꢀRenavd,ꢀP.ꢀD.ꢀChantal,ꢀS.ꢀKaliaguine,ꢀCan.ꢀJ.ꢀChem.ꢀEng.,ꢀ1986,ꢀ64,ꢀ
787–791.ꢀ
Synthesisꢀofꢀanisoleꢀbyꢀvaporꢀphaseꢀmethylationꢀofꢀphenolꢀ
[
withꢀ methanolꢀ overꢀ activatedꢀ aluminaꢀ supportedꢀ catalystsꢀ
wereꢀinvestigatedꢀinꢀaꢀfixedꢀbedꢀreactor.ꢀTheꢀKH PO /AAꢀcata‐
2
4
[8] S.ꢀR.ꢀKirumakki,ꢀN.ꢀNagaraju,ꢀK.ꢀV.ꢀR.ꢀChary,ꢀS.ꢀNarayanan,ꢀJ.ꢀCatal.,ꢀ
2004,ꢀ221,ꢀ549–559.ꢀ
lystꢀwithꢀtheꢀcalcinationꢀtemperatureꢀofꢀ700ꢀ°Cꢀforꢀ8ꢀhꢀgaveꢀtheꢀ
bestꢀ performance.ꢀ Theꢀ optimalꢀ Kꢀ contentꢀ wasꢀ 7.53ꢀ wt%.ꢀ Theꢀ
levelꢀofꢀanisoleꢀyieldꢀhasꢀaꢀmaximumꢀvalueꢀatꢀ400–450ꢀ°Cꢀinꢀtheꢀ
rangeꢀ fromꢀ 300ꢀ toꢀ 500ꢀ °C,ꢀ decreasedꢀ slightlyꢀ withꢀ increasingꢀ
WHSV,ꢀandꢀincreasedꢀwithꢀincreasingꢀmoleꢀfractionꢀofꢀmetha‐
nol.ꢀ Onꢀ comparingꢀ theꢀ O‐methylationꢀ andꢀ C‐methylationꢀ ofꢀ
phenol,ꢀ aꢀ lowꢀ reactionꢀ temperature,ꢀ highꢀ WHSV,ꢀ andꢀ lowꢀ
[9] S.ꢀC.ꢀLee,ꢀS.ꢀW.ꢀLee,ꢀK.ꢀS.ꢀKim,ꢀT.ꢀJ.ꢀLee,ꢀD.ꢀH.ꢀKim,ꢀJ.ꢀC.ꢀKim,ꢀCatal.ꢀ
Today,ꢀ1998,ꢀ44,ꢀ253–258.ꢀ
[
[
[
[
10] M.ꢀE.ꢀSad,ꢀC.ꢀL.ꢀPadró,ꢀC.ꢀR.ꢀApesteguía,ꢀJ.ꢀMol.ꢀCatal.ꢀA,ꢀ2010,ꢀ327,ꢀ
63–72.ꢀ
11] K.ꢀG.ꢀBhattacharyya,ꢀ A.ꢀK.ꢀ Talukdar,ꢀP.ꢀDas,ꢀ S.ꢀ Sivasanker,ꢀ J.ꢀMol.ꢀ
Catal.ꢀA,ꢀ2003,ꢀ197,ꢀ255–262.ꢀ
12] M.ꢀE.ꢀSad,ꢀC,ꢀL,ꢀPadró,ꢀC.ꢀR.ꢀApesteguía,ꢀAppl.ꢀCatal.ꢀA,ꢀ2008,ꢀ342,ꢀ
methanolꢀ fractionꢀ overꢀ aꢀ KH
2
PO /AAꢀ catalystꢀ withꢀ higherꢀ Kꢀ
4
40–48.ꢀ
contentꢀ favoredꢀ theꢀ increaseꢀ ofꢀ anisoleꢀ selectivityꢀ byꢀ
O‐methylationꢀofꢀphenol.ꢀTheꢀlevelꢀofꢀanisoleꢀyieldꢀwasꢀmaxim‐
izedꢀ underꢀ theꢀ optimizedꢀ reactionꢀ conditionsꢀ ofꢀ aroundꢀ
13] K.ꢀSreekumar,ꢀS.ꢀSugunan,ꢀJ.ꢀMol.ꢀCatal.ꢀA,ꢀ2002,ꢀ185,ꢀ259–268.ꢀ
[14] Q.ꢀY.ꢀYu,ꢀX.ꢀY.ꢀChou,ꢀC.ꢀH.ꢀXu,ꢀZ.ꢀL.ꢀXu,ꢀSpecialityꢀPetrochem.,ꢀ2009,ꢀ
26,ꢀ12–14.ꢀ
–1
[15] L.ꢀXu,ꢀS.ꢀJ.ꢀWu,ꢀW.ꢀX.ꢀZhang,ꢀM.ꢀJ.ꢀJia,ꢀG.ꢀLiu,ꢀActaꢀPhys.ꢀChim.ꢀSin.,ꢀ
4
00–450ꢀ°C,ꢀlowꢀWHSVꢀbelowꢀ0.18ꢀh ,ꢀandꢀhighꢀmolarꢀratioꢀofꢀ
2
009,ꢀ25,ꢀ242–246.ꢀ
16] G.ꢀSaralaꢀDevi,ꢀD.ꢀGiridhar,ꢀB.ꢀM.ꢀReddy,ꢀJ.ꢀMol.ꢀCatal.ꢀA,ꢀ2002,ꢀ181,ꢀ
73–178.ꢀ
methanolꢀtoꢀphenolꢀofꢀ5.ꢀTheꢀcatalystꢀpreparationꢀandꢀanisoleꢀ
synthesisꢀprocessꢀareꢀveryꢀsimpleꢀwithꢀlowꢀcostꢀandꢀaꢀrelativelyꢀ
goodꢀresult,ꢀandꢀthusꢀisꢀadvantageousꢀforꢀpracticalꢀapplication.ꢀ
Theꢀcatalyticꢀmechanismꢀwasꢀdeducedꢀtoꢀbeꢀthatꢀtheꢀadsorptionꢀ
[
1
Pageꢀnumbersꢀreferꢀtoꢀtheꢀcontentsꢀinꢀtheꢀprintꢀversion,ꢀwhichꢀincludeꢀ
2 4
ofꢀ phenolꢀ onꢀ theꢀ Kꢀ siteꢀ ofꢀ KH PO /AAꢀ andꢀ theꢀ adsorptionꢀ ofꢀ
bothꢀtheꢀEnglishꢀversionꢀandꢀextendedꢀChineseꢀabstractꢀofꢀtheꢀpaper.ꢀTheꢀ
onlineꢀversionꢀonlyꢀhasꢀtheꢀEnglishꢀversion.ꢀTheꢀpagesꢀwithꢀtheꢀextendedꢀ
Chineseꢀabstractꢀareꢀonlyꢀavailableꢀinꢀtheꢀprintꢀversion.ꢀ
methanolꢀonꢀtheꢀLewisꢀacidꢀsiteꢀasꢀtheꢀfirstꢀreactionꢀsteps.ꢀTheꢀ
+
–
followingꢀcombinationꢀofꢀtheꢀCH ꢀofꢀmethanolꢀandꢀtheꢀPh–O ꢀofꢀ
3
GraphicalꢀAbstractꢀ
Chin.ꢀJ.ꢀCatal.,ꢀ2016,ꢀ37:ꢀ720–726ꢀ ꢀ ꢀ doi:ꢀ10.1016/S1872‐2067(15)61074‐9
Synthesisꢀofꢀanisoleꢀbyꢀvaporꢀphaseꢀmethylationꢀofꢀphenolꢀwithꢀmethanolꢀoverꢀcatalystsꢀsupportedꢀonꢀactivatedꢀaluminaꢀ
ꢀ
DanꢀDang,ꢀZeꢀWang*,ꢀWeigangꢀLin,ꢀWenliꢀSongꢀ
InstituteꢀofꢀProcessꢀEngineering,ꢀChineseꢀAcademyꢀofꢀSciencesꢀ
H
CH
3
H C
3
O
O
+
H O
2
+
O
H
H
3
H C
H
O
O
K
Al
UnderꢀcatalysisꢀofꢀKH
2
PO
4
/Al
2
O ,ꢀphenolꢀandꢀmethanolꢀwasꢀactivatedꢀbyꢀKꢀandꢀAlꢀsitesꢀrespectively.ꢀAnisoleꢀyieldꢀdecreasedꢀwithꢀincreas‐
3
ingꢀspaceꢀvelocity,ꢀincreasedꢀwithꢀincreasingꢀmethanolꢀfraction,ꢀandꢀappearedꢀaꢀmaximumꢀvalueꢀwithꢀincreasingꢀtemperature.ꢀ