Ｏ−ｌCarbenyReactorによるＰＥ,PRＰＳの触媒分解
CatalyticdegradationofPE,
PPandPSbyCarber
TyReactor
正村田勝英（豊橋商工会議所）

Katsuhide
Murata,Toyohashi
Chamberof
CommerceandIndustr
yCatalyticdegmdationofpolyolefinswasperfbrmedinacont
inuou
snow
r
eactorthatallow
sthestu
dyofthe
degr
adat
ionpr
oce
sse
satst
cadyst
at
e
､
T
he
cont
inuou
sflow
Car
ber
Tyr
eactｏｒ
ｗ
ａｓｏｐｅ
魁te
datat
mospher
icpr
essur
eandatfｂｅｄｍｔｅｏｆＯ‐
１．
５kghF
1polyolefinsov
ertw
osilica‑aluminacatalystshav
ingdiffe
唾ntSi
O
2
1Al
2
03moleratio・
Polyethylene(PE),polypropylene(PP)andpolystyrene(PS)weredegradedat
420，

380ａｎｄ360℃r
espe
ctiv
c
ly､
Molar
rateofdegr
adationw
asincreasedinthepresenceofcatalys
ts,
how
ev
e
r
t
hc
massr
ateofdeg
r
adat
ionw
asde
cr
e
ased，
The
se
inte
r
estingr
esultsmightopennewperspectiv
esinunde『standingthe
macrosco
picmechanismfbr
cata
lyticdegradationofpolyolefins．
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1．Introduction

reactorcontent，Thevolatileproductsleavingthereactorwere
passedthroughawater壱cooledvcntcondenser・Thecondensed

Sincethelateofl97０，s，alotofworkoncatalytic
degradatiｏｎｏｆｐｏｌｙｍｅｒｓｗａｓｃａｒｒｉｅｄｏｕｔｂｙｕｓingbatchreactor
systemstoinvestigatethee雄ctivenessand/orthemechanism
duringdegradationovcrvariouscatalyticsystems・Thesesystemscouldactasrealcatalystsor/andasreactantｓ(oxygcndonor)．Ｉｎｍｏｓｔｏｆｔｈｅｐｒｅｖｉｏｕｓｓｔｕｄｉｅｓｏｎｔｈｅcatalytic
degradationofpolymers，researchershavenotdistinguishedbetweenthetwofimctionsofthecataIyticsystemsbecausethis
isdifficulttobeanalyzedinabatchreactor,Carberryreactor(acontinuousflowoperation）isasuitablctechniquetostudythc
catalyticdegradationof
polymersbecausetheexper
imentaldataarcobtainedatsteadystate，ｔｈａｔｉｓ，atconstanttcmperaturc，

liqu
idpr
odu
cts
(oils)
w
er
ecollectedinar
eceiv
er
hav
ingaglasslevelgaugewhilethegaseousproductspassedthroughasealpotandagasmeterbefbrecollcctionfbranalysis，Thccatalyst/polymermassratiowasofaboutl/lOinour

experimentalprocedur
ethatismuchs
mallercom
paredtootherprocedureswherehigheramountsofcatalystsareused（evencatalyst/
polymermassr
atioofl/1)．

ドL
雲童

constantpressureandconstantamountofreactorcontcnt・The
authorpreviouslyreportedonthethermaldegradationofPE,PPandPSinacontinuousflowreactorI),
aswellasontheefYectof

鐘reactionpressure2)．
InthepresentstudytheauthorcarriedoutthecatalyticdegradationoｆＰＥ,ＰＰａｎｄＰＳｏｖｅｒｔｗｏｔｙｐｅｓｏｆ
ｓｉｌｉｃａ−ａｌuminacatalystwithdi賑rentSiOz/Al203ratio，ina
continuousflowreactor．

Ｌuq品…

2.Experimental

FiglCarberryreactorfbrcatalyticdegradationofPE,PPandPSinacontinuousnowoperation．

PE（highdensity),ＰＰａｎｄＰＳｗｅｒｅｏｂｔａｉｎｅｄｆｒｏｍＭｉｔｓｕｉ
Ｃhemicals,Inc,ThecatalystsemployedinthisstudｙｗｅｒｅＳＡ−ｌ3.ResultsandDiscUssion

ａｎｄＳＡ−４ｃｏｍｍｅｒｃｉａｌｓｉｌｉca‑aluminafomMizusawaChemicalThemassrateofvolatilizationincreasedwithdegradationtemperature(Fig.
２a),thevariationdecreasingintheP
S＞
ＰＰ＞ＰＥｏｒｄｅｒｔｈａｔｍｉｇｈｔｂｅｅｘｐｌａｉｎｅｄｂｙｔheoppositetrendfbr
thermalstabilityofthese
polymers・T
hecatalyt
icdegradationdecreasedthemassrateo
fvolatilizat
ion,thee
f
Ibct
be
ings
mall
fbrPETheactivationenergieswerecalculatedけomArrhenius
plotsdraw
nbasedonthemassrateofvolatilization（Fig.
２b)．
TheyincreasedfbrcatalyticdegradationonSA‑
lcomparedto
thermaldegradationasfbllowing:from220.9ｔｏ230.5kJfbrPE，

lndustriesCo・
Ltd・
Japan，
hav
ingSiO2/Ａｌ２０３ｍｏｌｅｒａｔｉｏｏｆ５､
０and0.
42andBETsPecificsurfhceareaof
420and2
40m2
g1rcspectiv
eIy･
Fig.１ｓｈｏｗsaschematicdiagramoftheexperimentalset‑up
uscdfbrcatalyticdegradationofPE，PPandPSundercontinuousflowOperation・Thedegradationwasperfbrmcdina
stainlesssteelvesselreactorof51ｖｏｌｕｍｅinwhicharotating

cagcthatcontainedlOOgofcatalystwasinstalled・The

polymerswereheatｅｄａｎｄｍｅｌｔｅｄａｔ２００−２２０℃insidean

ｆｏｍ２１６３ｔｏ２１８,okJfbrPPandfrom207､５ｔｏ221.0kJfbrPS

extruderthcnfbdintothereactoratdesired企edingrate

intothereactor・Ｔｈｅｎｔｈｅｒｅａｃｔｏｒｗａｓｈｅａｔｅｄｕｐｔｏｔｈｅfinal

Itisclearthattheactivationenergiesofthermaldegradation
wereincreasingwiththethermalstabilityofthepolymersand
werchigherfbrcatalyticdegradation、Ｔｗｏｄｉｓｔｉｎｃｔｅ鮭cts

degradationtemperaturcof420,380ａｎｄ360℃fbrPE,PPanddecr
easethcmassr
atco
fvolatilizationfbrcatalyticdegr
adatio、PSrespectively・Whenvolatileproductsbegantobeobserved，comparedtothethermaldegradation．

betwcenOandl､
Ｓｋｇｈ.
'、Firstly,ａｂｏｕｔｌｋｇｏｆ
ｐｏｌｙｍｅｒｗａｓ企danaliquotamountofraw
polymercorrespondingtotheoutput

ＥｎＥｃｔｌ：(liquidproduct＋gases）wascontinuously企dintothereactor
bytheextruder・Therateoffbedinputwasgraduallyadjustcdto
thatofproductoutputinordertokeepconstanttheamountｏｆ

Intheprecedingpapers[1,2]theauthorproposedamacroscopicmechanismfbrthermaldegradationofpolyolefinsbychainreactionsinvolv
ingfr
eer
adicals．

１
１w
eightside・S
incctherateofchain‑ends
cissionisproportionalF2錦

influenced
凶Ｐ

じｒ︑

●０ｈ句、

１

EfYbct2：

つ銘ＡＣトムＳＡ−０Accordingtotheabovementionedmacroscopicmechanismthe
molcculesinsidethereactorcontenthavealongpartofthechainanchoredintheliquidphaseandashorter
partattheendＰＥ

ofthechainthatshiftstothevaporphaseduetothestrong

伽．

﹄二・哩砦軍二・一三一一罵這言一︷︾・こ匡含胃﹄芳舞一一

tothenumbcrofmolecules，themassrateofvolatilizationis

kineticenergy，Thevehementmovementsofthechain‑endin／：(:ｉ４ｃ300thevaporphasecausethescissionofthe
chainatgas‑
liqu
idintcr
face・
Mor
eov
er，thechain‑
ends
ci
s
s
ionat
g
as‑
liq
u
i
dinte
r
f
lce
cau
se
ate
mpe
r
atu
r
edr
opbetw
e
cnthe
l
iq
u
i
dandv
apor
phasethatu
suallyexceed５０℃.
[2]Long‑chainmoleculescould

380４００４２０４４０

１﹄一一・謹二へ麺二・富邑窒男電一一富雷一己．Ｐ・一︽︾︾一君﹄α雲二〆０１０Ｔｒｍｐ
どr
8Qq
Mr
＆．
⑥
Ｃ

beproducedhavingtheboilingpointhigherthanthe
tempcratureofthcvaporphase・Assoonastheyjumpupinto
thevaporphase，theycondenseinliquiddroplets（veryfineparticlelikeafbg)
duetoatemperaturedrophomtheliquidtothevaporphaseinreactor・Ｔｈｅverysmallliquiddropletsarc
transportedoutofreactorbytheupwardhighstreamofvolatileｕ 、 罰

products､Thistransportphenomenonincreasesthemassrateof
volatilizationandexplainsthepresenceinIiquidproductsof
compoundswithhighboilingpointsthatnormallyshouldnot
leavethereactor・

ＦｏｒｅｘａｍｐｌｅｔｈｅｖａｐorphascfromdegradationofPPat

380℃hadatempcraturebelow330℃thatisequivalentto
n‑C20,however,theNPgramoftheliquidproductofPPshows
theliquidproductcontainSSigni
ficantamountsofcompounds・AndtheNPgramoftheliquidproductｏｆＰＥｓｈｏｗｓａｓｗｅｌｌｉｎｇ

０００．００１３５0.00145

Ｗ､Ｋと，000155０００１６５

ｏｎｔｈｅｃａｒｂｏｎnumberdistributionaroundn‑C20resultedfi｢omFig2VariationofmassrateofvolatilizationwithtcmperatureandArrheniusplotsfbrcatalyticdcgradaｔｉｏｎｏｆＰＥ,PPandtheabove‑mentionedcfYEct、

PSoversilica‑alumina．

Meanwhilethesupplementarychain‑endscissionsoccurring
duringcatalyticdegradationdecreasetheｓｉｚｅａｎｄｔｈｃｂoilingpointofthemolecules，Thefbrmationofliquiddropletsinthevapor
phaseandthe
irtrans
portoutofreactor
inthe
pyrolysisoil
isdiminishedcomparedtothermaldcgradation・ForPP
degradationthisisobservedbyalmosttotaldisappearanceof
compoundsaboven‑C20inpyrolysisoi1s、Ｔｈｉｓｃａｕｓｅｓａ
ｄｅｃｒｅａｓｅｉｎｔｈｅｍａｓｓｒａｔｅｏｆｖolatilizationduringcatalytic
degradationcomparingwiththermaldegradationofpolymers・
Thelattercffbctrclatestothedisputeconcemingtheactivationenergyofdegradationcalculatedfomthemassrateof
volatilization・Athighertemperaturestherearｅｌｅｓｓａｍｏｕｎｔｓ(relativeamountsinmassrate）ofdropletcomponcntsfbrthe
thermaldcgradationduetoasmallerdropintemperature
betweenliquidandvaporphase.[2］Conscquentlythcincrease
ofmassratcofvolatilizationduetotransportphcnomenonofd『opletsbecomesneglig
ible､
Ｔ
ｈｉｓe
xplainst
helower
differences

TwomaintypesofC‑Cbondscissionsimultaneouslyoccur
dur
ingt
her
maldegradat
ionandarcresponsiblefbrthereduction
ofthemolecularweightoftheproducts・OneisarandomscissionofC‑Cbondswhichcausesamolecularweight
reductionofraw
polymerintos
malleroligomer
s
incr
eas
ingt
h
e
reactorcontentTheotheroneisachain‑endscissionofC‑Cbondsgencr
atingvolatileproductsw
hichcau
sesthedissipationofr
eactorcontent,
Thevo
lati
lepr
oductsarenot
fbr
meddirectl
yfromthcinitialmacromoleculesbuttheyresultfmmthc

degr
adat
iono
foli
gomer
sinr
eactor
cont
ent､
T
her
at
iobetｗｅｅｎ
ｔｈｅｔｗｏｔｙｐｅｓｏｆＣ−Ｃｂｏｎｄｓｃｉｓｓｉonsdependsonthepolymer
typeandaffbctsthepropertiesofthereactorcontentand
volatiles,asdescribedabove,Thechain‑endscissiontakesplace

atthcgas‑liquidinterfaceinwor
kingr
eactor,Consequcnt
ly,thevolatilizationofproductsduringthermaldegradationof
polymcrsisaheterogeneousreactioninwhichthereactantisin
aliquidphaseandtheproductisinagasphase，Forthecatalyticdegradationofpolymersthereaction
systemismuchmorecomplicatedthantheabovementioncd
reactionsystemfbrthethermaldegradationofpolymers，
bccauseitinvolvesthreephase(gas,liquidandsolid),namely，
threephasereactor・Silica‑aluminacatalysthasaremarkablee鮭ctontheproductdistribution，ｂｕｔ、otonthemassrateof(approachingtozeroat440℃）inmassratcofdegradation
betweenthcrmalandcatalyticprocedurcfbｒＰＥｃｏｍｐａｒｅｄｔｏＰＰ
ａｎｄＰＳ．

RefErences[1］Ｋ､Murata,Ｙ・Hirano,Ｙ・Sakata,Ｍｄ.Ａ,Uddin,Ｊ､AnaL
Appl,Pyro１．６５(2002)７１−９０．
[2］Ｋ､Murata,Ｋ，Sato，Ｙ､Sakata,Ｊ,Anal・Appl、Pyro１．７１

volatilizatio､，asshowninthepreviouspaper［3]・Thisexperimentalobservationsuggcststhatthecatalystaccelerates（2004)569‑589．

[3］KMurata，Ｍ・Brebu，Ｙ・Sakata，Ｊ・Anal・Appl、Pyro１．

thechain‑endscission，butnottherandomone､Asaresultthe

６(2009)354‑359.

distributionofreactorcontcntshifistothehighermolecular1２