研究論文川

(1)

研究論文川

^‖‖‖

川 ‖

‖‖

‖ l ‖ l ‖

Theexotherm al decom po8ition ofnitrocenul oBein m ixed acids

Hidet8uguNAKAMURA●,NoriakiMATSUtJRA',Miyah A灯 YOSHr andYa8utakeHARA●

Theexothemi cdecompo8itionofmitrocelluloSeina801utionofmiXcdacidwas8tudiedinorder todetemi nethecondition8for88fepzd uctionofnitrocellul08ebymeansOfthenitrationofceuu･

losewithmixture80fmitricacidand8ulphuricacid.Ⅰ80thennaldecompo8itionteStBWere也rried outandatemperature8ughtlyhigherthanthenitrationtemperatureinmanuhcturingwa8adopted a8aneXperimentalcondition.There8ultsobtainedareaBfouow8.

NitroαnulOseinmixedacidunderwentexothemi cdegradationaReralonginductionperiod. whidhwasaqectedbythereactiontemperattwe̲ThSdegradation8howedthemaximumratein themiddleofthereaction,whichindi切tedthereactiontobeauto飴talytiC.TheaCtiqtionener･

gie8ObtainedbyAm heniu8plotsofratecon8tant8fromtheautcNntdyticrateequationwere31.4

‑59.1kJ/mol.Moreover,plot80fthelogaritlm oftheinductionperiodtv8.theizIVerSeOfreac･ tiontemperatureal808howedgoodlinearityaccordingtotheAn rhemiuS･typeequation,andthe obtainedactivationenrgie8Were37.3‑60.4kJ/mol.

Theinductionperioda氏erwhichtheexothem icreactioncommenceddecrea8edwith thein･

creasingNC/nixedacid8ratio.An increa8einthecontentofnitricacidinthem也 dacidthen hadadecreasinge飽ctontheinductionperiod.MoreovezT,thisdegradationwasaffectedbyatmo･ 8phericgaBeS,andnitrogendioxideacceleratedthereaction.

1.(ntrodLJCtjon

Nitro喋11ulose(NC,Nitrccotton)i8OneOfthemo母t reactivechemi Cal畠.Becau8eOfthi卓reactivenature. enornou8丘柁8andincidentalexplo8ion8havebeen reportedinit8manufacturing.Moreover,agingof nitroceLlul08eunderlongterm StorageCauSe8a changeinthepracticalperformanceoraninciden‑

talexplo8ion.Extensivedataontheapngofexpl0‑

8ive8hvebeenaccumulatedfromtheviewpointof SafetyinmiLnu血cturizIg,Storage,andu8eOrOpera‑

tionalreliabilityJ)･2川 .However,fewkineticdata areavailableonnitrocellul08edecompositionin mixedacidwhicharerequiredforSafeproduction.

ⅠnthisPPer,thethem albehaviorofnitro伐Ilu‑

108einasolutionofmixedacidwa卓8t.udiedinorder ReceivedonSeptember3,1999

'DepartmentofAppliedChemistry,FacultyofEtlgi･血eering,Kyushuh8tituteofTeclmology,SetlStli, Tbbata,Kitakyu9hu,804‑8550JAPAN

でEL093‑884‑3319 Fm 093‑884‑3300

todeterninethecondition8for8afeproductionof

nitrweuulOBebymeAZ旭Ofthenitrationofcellul08e w

ithmixtures0fnitricacidand8ulphuricacid.As anexperimentalmethod,iBOthem alde00mpo8ition experiment8WereCarriedoutattemperature8rang･ ingfrom50‑78℃ whichareSlightlyhigherth n thenitrationtemperatureinpracticalmanuLhctur‑ ing.Baaedonthecon8iderationoftheeZrectoftem･

peratu代.NC/acidratio,andacidcompositiononNC deoompo8itioninthemixedacid,thethermal de･ compositionbehaviorandmecha血Bm80fnitroα1‑ lulo8einmixedacid wereinvestigatedtounderl 8tandthethermalbehviorof血trationduringthe practicalnitrationpro0088inordertodetem inethe condition8for組feproduction.

2.Experhenta1 2.1Materials

Fourtypes0findu8trial gradeNC8ample8used intheSee叩erimentSWereSuppuedbyAs atdChemi ‑

‑)08‑ 火薬学会法

(2)

Cal Indu8tryCo.,Ltd.LBtypeNCi8inpowdered form anditsnitrogencontenti8ll.6%.LA type NCiSinacottonflakeformhavingamitrogencon･

tentofll.8%.HBtypeNCiBinapowderedforn havinganll.8%nitrogencontent.HAtypeNCi8 inacottonflakeformhavinga12･1%nitrogencQn‑

tent.

MixedacidshavethecompositionsOrnitricacid (HNO3)/sulphuricacid(H2SO一)/water(H20)≡60/

20/20,50I30/20,40140/20,30/50/20and20/60I20by weight.Thermalanaly8eSWereCarriedoutfor Samplesofthemixture8with960part80fmixed acidaTd4part80rNC,480/4,240/4,96/4and48/4.

2.2111erTTlalanalysis

Thermal analySi8W88performedusingahand‑

mademicrocalorimetricapparatu8underargong舶 atmosphere,inwhichtheheatingratewas2冗/min andtheSampleweightwas900mg(36mgofNC and864mgofmixedacid).PrehJninazyexperiment8 showedthatthetemperatureri8eintheSampleSol 1utionofmixedacidandNCcauBedbyexothermic deoDmpOSitionwa8within1K

Exothernicpropertie8inthei80therTnaldeoDm‑

positionofNCwereexaminedusingthehndJnade microcalorinetricapparattはunderatmo8phere80f argongas,air,andargonwithaboutIvol%Tdtro一節ndioxide.Ⅰ80thermaloperationofthermdanaly‑

seSforNCinmixedacidwasCarriedoutattem‑

peraturesrangingfrom50‑75℃.

3.ResLJlb

3.1TherrTlaldecornpositjonofnitroceltuloseinmixed acid

Fig.18how8anexampleoftheDTAcurve8forNC (4wt%,LBtypeNC)inmixedacid(96wt%,HNOJ H皇SO4III20=60/20/20byweight)underargon.NC begantoundergoexothermicdecompo8itioninthe mixedacidatatemperatureof65℃,evolvingnil trogendioxidep8.Tl血 exothemi crt!actioncea8ed atthetemperatureofabout90℃,producinga browni8hyeuow80lution.Thede00mpoSitiontem･

peratureSdonotdi飴rwiththetypes0fNC.Ptlre nitrooellul08edecompo与edthermaIlyattempera･

tureSrangingibm 180‑ 250℃ inargon.Thus, t

heNCdecompositioninmixedacido∝uTedata lowertemperaturecomparedwithpureNC.

.Oy311V･1.OPUU .OYullVL.OPUU

HA

rlD LlL∧) . t l l t l ●

60 80 l ‑

100

TenTXmtUre(o C)

Fig.1AnexampleofDTAcurves0fNCinmixed

addTemperat ure 50●

6 5

5 60 65

70l l l

0

⁵⁰ ¹⁰

0 150 Fteactlontime

(mln.) Fig.2Ⅰ80thermal decompo8itionofNC(

36mg)in m

ixedacid(864mg,H2SO4/HNOB/w

ater=60/

20/20byweight)obtainedbymicro･Calorim‑

etry

3.2JsotJlermaLdecomposh'Onofnibocelluloseinmixe d acid

Underi80thermalcondition,NCunder

wentexo‑ t

hernicdeconpo8itioninmixedacidat

tempera‑

tu re8rangingfrom50‑75℃ within400

minutes. Fig‑28howSthe柁8ult80fiBOthem dde00

mposition ofNC(36mg,LBtypeNC)inmixedaci

d(864mg, H2SOJHNO3/water=60/20/20byweight)

underar･ Eonobtainedbymicrocalorinetry.Ther

earetwo KayaktJGakkaishi.VoL61.No.3.2000

(3)

Tab一e1Inductionperiodandkineticparameter8at variou8temPZBture8forthethem ddecom･

po8itionofNCinmkedacidundera喝on Tbmp. jRateconStantk,Inductiontime

(℃) (min.‑1) (mh.) 0･009 414 0.018 184

Mixedacid:NCOB typeNC);96:4Qyweight). Mixedacid;HNO3/H2SO一/H20≡60/20/20by weight.)

1/∫ Fig.31ntv臥IFrplotwithrega

rdtoFig.2 chmcteri8ticfeatu柁8

(4)

C(‑t

邑

q

Fi85Apph租bilityoft

heresults0fFig.3totheau‑

tm talyticrateequ

ation(2) OEtenrepresentsanautOCatalyticr

eaction.Fig.5 8how8theapplicabilityofthe柁8ult8

0fFig.4tothe autlocAtalyticrateequation(2).･

n(I/(1‑Ⅹ))≡kt (2) wherexi8thefractionaldecompo

8itionofnitrocell lul08eCalCulatedfrom thet

hermogram inFig.2,k theratecon8tantfortheautoCatalytic

decomposi‑ tionandtthereactiontime.Thispl

ot8how8good l

inearity,Andtheobtainedrateの

n8tant8are8hown inTablel.Am he血 plotsoftherateCOnBtan

t8k obtainedfromFig.4gaveanactivationenergyOf

57 kJ/MamonyNCdel. composition8tudie8indica

tethatthe decompositionofplm dryNCfomow8theaut

ocatal lyticrateequation2lduetothecatalytic

natureof ド:S:W

(bywt.) 60:20:20 50:30:20 40:40:20 30:50:20

20:60:20 theproductnitrt)genoxide8.Our

NCdemmpo8i･

tionexperimentsinmixedacida180f

ollow8the8&me rateequationbutwithalongeri

nductionperiod.

Theactivationenergyofthedryde00mpoSit ionalso diqer8tiom thatinthemixedacid,aJldtho8

eval‑ ueswerereportedtobe

180‑200kJ/mo13).n u8,it canbededucedthtthed

econpo8itionmechniBmB ofNCin thedryconditiona

ndin themixedacdare different.

3.4EffectOf

somefactorsonthedecomposh'onofn卜 trocel

luLoseinmixedacid lnordertocon8idertheeLr

ectofcompo8ition80f m血 acid,isothermalexperimen

t8WereCarriedout f

orthemixedacidwhichconsist

edofnitricacid (HNOa)/Bulphuicacid任Ⅰ2SOJ/w

ater任Ⅰ20)≡60J20/

20,50/30/20,40/40/20,30/50/

20and20/60/20by weight,respectively.Everycompos

itionhadanin･

ductionperiod,and丘actionalde

compositionvB.time curveや8howeda8igmoidalSha

pe.Table2Bhow8 theinductionperiod8andkineticp

arameter8for variousacidcompo8itionS.A8Stated

before,thein･

auctionperioddecrea8edwithanincr

easeinthe NCImixedacidratioorwithaninCrea8

einthecon‑

centrationofnitricacidintllenixe

dacid.Regard‑

ingtheratecon8tant8,the8ame

re8ultSWereOb･

taiJledwithresp

ecttOtheinductiontime.ThatiJB, themteconB

Ltantkfortheautoはtalyticde印mpoSi･ tionincre

asedwithanincreaseintheNC/mixed acidratioorwithanincreaB

ein theconcentration ofmitricacidinthe

mixedacid.

Fractionaldecomposition(x)V8.timecur ves0b･

tainedfmmtheiBOthermaldecompositionof NCin Table2KheticparameterBfortlledccompo8itionofNCinmix

edacid f

orvarioueacidcompoBi

tionB 1bmp.℃ Ratecon8

tant(Inductiontime)

竺̲ , r 一一｣

｣竺0.039(187)0.023(24

0) 0.018(294) 0.01

2(352) 0.008(458) 0.063

(96) 0.044(

129) 0.035

(144) 0.022(159)

0.017(244) 00000.1....0000075436(65(77(87(80(901122967)))))000.1.1.6372(2(10363nl■u)

lot(JI8) Ea(I⁴ndue⁽³^kJ/md)^.¹⁽t⁴i⁶on

t i

^me⁾

.7) 48.0(50.1) 51.3(52.9) 0.075(53); 55.2(55.3)

研究 論文 川