TllE REa't E\c OF PHYSICAL C}IEat[sraY OP JAYAV, VoL. 29, Nu. 2, JIAR STUDIES ON EXPLOSIVE REACTION OF VINYL CHLORIDE MIXED WITH OXYGEN

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1 Ttle Studes on explosve reacton of v oxygen Author(s) Suga, Masao Ctaton The Revew of Physcal Chemstry of 80 Issue Date URL Rght Type Departmental Bulletn Paper Textverson publsher Kyoto Unversty

2 The Revew of Physcal Chemstry of Japan Vol. 29 No. 2 (1959) TllE REa't E\c OF PHYSICAL C}IEat[sraY OP JAYAV, VoL. 29, Nu. 2, JIAR STUDIES ON EXPLOSIVE REACTION OF VINYL CHLORIDE MIXED WITH OXYGEN By MASAU SucA (Receved February IS, 7960) The exploson lmts of vnyl chlorde mxed wth oxygen are determned a[ reduced pressures by the admsson method. Isochors and sotherms of the exploson lmt and also the colors of gnton Homes ace shown. There s no essental dfference between the behavor of vnyl chlorde mned wth oxygen and that of ethylene mxed wth oxygen except the generaton of hydrogen chlorde under the slow reacton. Patterns of these exploson lmts are smlar to each other. The nducton perods n the exploson pennsula of vnyl chlorde mxed wth oxygen have also been measured and [ s found tlmt these perods are shorter than those of ethylene mxed wth oxygen. The apparent actvaton energy o{ the reacton s estmated from the exploson lmts of vnyl chlorde mxed wth oxygen accordng [o Semeno6's theory and ts value, 8, s about 34 kcal. In recent years vnyl chlorde has come to assume commercal mportance as a monomer of ts polymer. There are a few datatl n the lterature n regard [n lm[ of nflammablty", but observatons experenced under certan condtons can hardly 6e accepted as ndcatve of the mnnomer~s safety range n other set of condtons. And wth the ncreasng use n ndustry of monomer vapor at elevated temperatures and pressures, t s mportant for nformaton relevant to these condons to be aa-alable over suffcently wde ranges. In the prevous papers? a +>, the exploson lmt of ethylene mxed wth oxygen and that wth the ar were determned by the "admsson method ". The present author has tontnvally studed the exploson lmt o[ vnyl chlorde mxed wth oxygen by the same method. for the purpose of ganng the knowledge of the explosve reacton. These results are compared avth the results of ethylene mxed wth oxygen and brefly dscussed. In ths case, the results- obtaned are unsatsfactory from the practcal pont of vew. However, t s nterestng to menton [hat the exploson pennsula s found also n the exploson lmt of vnyl chlorde mxed wth oxygen, and t s made sure that the exploson pennsula nvolved n the exploson lmt of ethylene mxed wth oxygen s not the sole nature oc ethylene tself as reported n the prevous works), Expermentals I) Dvson Coatng Techncal Servce Bulletn, I'nyl Chlorde :Ifonorne., The Dow Chemcal Co. plastcs 2) h1. Suga. Dull. Chem. Sac. Japan, 31, 515 (1958) 3) N1. Suga, bd., 32, 425 (1959) 4) \f. Suga, Thr Journal. 2g, 67 (1959)

3 The Revew of Physcal Chemstry of Japan Vol. 29 No. 2 (1959) 74 T1. Saga Materals The vnyl chlorde employed n ths experment was prepared by dehydrochlornatng 1, 1-dchloroethane (b. p. 83S`C) through the anon of alkal n methanol soluton and then stored n a 'small cylnder. When necessary, t tuns fractonated, pur5ed by the acton of concentrated aqueous soluton of sodum hydroxde, ammoncal cuprous chlorde soluton and dlute sulfurc acd. and then dred wth soda lme and phosphorous pentoxde. employed was obtaned from a commercal cylnder (purty: The oxygen 99.4;.). after beng passed through a tran of bottles wntanng a concentrated aqueous soluton of sodum hydroxde, concentrated sulfurc acd and phosphorous pentoxde. Apparatus and procedure The apparatus used and the procedure adopted were of the types descrbed n the prevous paperz> except [he removal of the mercury manometer prevously connected wth the reacton vessel, takng nto consderaton the mercury vapor effects on the exploson lmt. Next, snce [he results were partcularly nfluenced by the prevous hstory of the reacton vessel and these effects not beng reproducble, the followng standard procedure was adopted for the purpose of elmnatng these effects. Alter a prevous run, the reacton vessel was heated [0 600 C and evacuated to 10-ammHg for an hour. Pressure change was measured wth a movable membrane manometer contanng a thn mca or alumnum membrane, wth the object of recordng the pressure-tme curve. Thereupon, the dsplacement of membrane was recorded by an nk oscllograp6 and stran meter` cmmected wth a stran gauge pasted on the membrane. But on the general expermental runs of the determnaton of the occurrence of exploson. all manometers were removed n order to smplfy the operatons. Results and Consderakons Observaton The determnaton of the occurrence of exploson was made drectly by naked eyes. The results of observaton are cla_ss5ed thus: I) After the ]apse of varous nducton perods (usually less than IOsec) lumnous flames (blue, green or yellow flames) were normally preceded by a glow whch rapdly bult up nto a brght Sash 511ng the vessel and accompaned by a sound. 1) After the lapse of relatvely longer nducton perods, pale blue flames were ohserved n the dark room. 3) After the lapse of shorter nducton perods, consecutve glows were observed for several seconds n the dark room. oxygen. 4) No change was observed. Ths s not found n the experments of ethylene mxed wth I[ was notced that the whte products, presumably polymer, adhered sometmes on the nner wall of the vessel after the reacton n case (3). Besdes, after the exploson of case (1) black products contanng carbon were found on the nner wall of the tube connected wth the reacton DS~P type mre resstance stran meter, Shnkoh Communcaton Industry Co., Ltd., Tokyo

4 1 The Revew of Physcal Chemstry of Japan Vol. 29 No. 2 (1959) Studes on Expbsve Reacton of Vnyl Chlorde mxed wth Ozygen 15 vessel. It s ponted nut that [hs phenomenon dffers from the case of ethylene mxed wth oxygen Fne pont asde, cases (1), (2) and (3) are convenently defned to be the explosons. Recordng of pressure varaton wth tme The typcal pressure-tme curves whch were measured by means of the movable membrane manometer are schematcally ndcated n Fg. 1. Curve (A) ndcates a very rapd ncrease of pressure wth lumnous yellow, green or blue lal ~a) ~---- (C7 - ~ ~-- ~---' -.. (D) r s. Tme 1 Schematc pressure-lme curves!lames and ths Corresponds to a normal gnton. Curve (B) shows the pressure change whch appears to be a two-stage gnton and occurs under condtons near the thermal exploson lmt. Dark blue flames whch occured on the vessel wall grew mmedately nto lumnous flames. It s consdered that curve (A) s essentally the same as curve (B). Curve (C) ndcates a feebler and mlder ncrease of pressure due to slower reacton than n the case of curve (B) and s ac U d f00 Fg. 2 soc6ars for ezploson lmt of vnyl ehlorde oxygen mxtures e E v F 550 Curve I-20g', 2-40$b, , 4-80% vn} 1 chlorde 500 a z 3 0 ao zoo Pressure, mmhg

5 The Revew of Physcal Chemstry of Japan Vol. 29 No. 2 (1959) 16 3I. Suga companed wth pale-blue (lames found under the explospn pennsula. Curve (U) ndcates no ncrease of pressure wth no flame. Ths corresponds to the so-called "slow reacton". The exploson lmt of vnyl chlorde mxed wth oxygen Isochors were determned for the mxtures of the varous compostons. 'Some of [he sochors are shown n Fg. 2. Only the sotherm at 600 C s shown n Fg. 3. The curves shown n these fgures exhbt the mnma, t ~, m K ' I c`7r o I S c, 1 ' e'1 Er I E ~ ~ ~ Green flames 1 Yellow (tames ' E CTI q c r ~- ~. 1 1 / G e ~ $ / r. o U / j 3011 l0u \ r 1 / / _ ~ ~ _ / 100 e Clue flmn f0 70 8D Volume.t' of vnyl chlorde n gas mxture wth oxygen Fg. 3 Isotherm for exploson lmt of vnyl chlorde-oxygen mxtures at 600'C at the composton of about 50% vnyl chlorde and the exploson lmt stuated about 3~95p vnyl chlorde (contanng glow range}. The exploson pennsula s found a[ the defnte temperature and n pressure condton s the mxture range o vnyl chlorde as ndcated n the lower closed curve n Fg. 2. The glow whch was observed n the regon of [he mxture of more than 90 a vnyl chlorde could not be recognzed n the case of ethylene, and ts presumed lmt s ndcated wth the broken lne. The exploson pennsula The exploson pennsula les on the range bounded by the frst and second pressure lmts of the explosons wth whch pale blue flames occur. Fg. 4 shows sochor for the exploson lmt o[ 20% vnyl chlorde mxed wth oxygen. Qn, Q and x ndcate respectvely the cases Q), (2) and (4) of the observatons. Also, Q ndcates the case of the lumnous flame propagatng nto the storage bulb through the nduced capllary tube owng to very short nducton perod. The broken lne n Fg. 4 represents the exploson of 20% ethylene mxed wth oxygen. AC ths pont, [he present author frst consders that the exploson pennsula of ethylene mxed wth oxygen was not always related to the nature of ethylene but was caused by carbon monoxde accumulated n the slow reac[ons <). Then, the followng mechansm s supposedr.): 5) C. N. Ilnshelwaod, The 6:nelcr of Chemcal CGange, Oxford (1940), p. lg8

6 The Revew of Physcal Chemstry of Japan Vol. 29 No. 2 (1959) Studes an Explosve Reacton of Vnyl Chlorde mned wth Oxygen ~d6 ~o 1tSa o$ o~ 3b1 0 e u 45'9 ~ ~ m Fg. 4 Exploson lmt of 10 S vnyl x x O O1'0 chlorde mxed wth orygen 174A O G13 O O ~.p (Inducton perods n seconds are O 6r x`~ x ndcated by numbers besde $ SOLI 48b observaton ponts.) E,rte, oa ,2 0, x x x t, o 1D.J zsgo o ; ~ x ' 14 o O x x x ~ X -+( x a~00 50 l0u Pressure, mmhg CH;= HCOH HCOH -~ HCHO ~ HCOOH -~ H:CO, CH.~ HCH ~ HCOH CO+H: CO+A: CO+H-O COo+H:O In analogy to [hs mechansm t s consdered that n the case of vnyl chlorde, carbon monoxde s accumulated and s followed by the generaton of hydrogen chlorde n the process of slow reacton. CH, HCOH HCOH J HCHO --~ HCOOH ~ H.COz CHCI ~ CIA ~ CI(;OH ~ HCI+CO CO+H:O CO:+H:O If [he essental dfference be[a'eea the respectve behavors of ethylene and vnyl chlorde mxed 700 U ~ ~ GO nz ro lox r 6(10 Is~ ~~ 550 n Fg ( U 350 Pressure, mmhg (sochors foc exploson lmts of vnyl chlorde-oxygen mxtures

7 The Revew of Physcal Chemstry of Japan Vol. 29 No. 2 (1959) 7s M. Suxa wth oxygen s the generaton of hydrogen chlorde, the dscrepancy between the exploson lmts s well understood n conformty wth the factsf that hydrogen chlorde s an nhbtor of carbo monoxde oxdaton. Fg. 5 shows the varous sochors far the exploson Iml of amyl chlorde mxed wth oxygen. whch ndcate the carous shapes of the exploson pennsula accordng to [he composton of gas mxtures. That s to say, [he composton of gas mxtures consderably affects the exploson lmt, and partcularly t s notced that the exploson pennsula dsappears at over 2~ vnyl chlorde. It s smlar to the case of ethylene. The exploson lmt and nducton perod The results of the experment wth regard to the nducton perod are shon n by numbers besde the observaton ponts n Fg. 4. The nducton perod was measured by a stopwatch. Fortunately, the nducton perods are farly long n the regon of the exploson pennsula and are reproducble so far as precautons are taken n accord wth the standard procedure. Pg. 6 shows [he relatonshp between the exploson lmt pressure 1~ ` m x e a ~T6e ~ `\ second pressure lmt v w a The 5rst pressure lmt 10 Qb, ~0C 0 o so loo Iso 200 ~0 3ao aso aoo asa Inducton perod, sec Fg. 6 Relatonshp between the exploson lmt pressure and nducton perods at the defnte temperature for 2096 vnyl chlorde mxed wth oxygen Table f The for nducton perods 2096 ethylene or (n sec) at the defnte vnyl chlorde mxed w pressures th oxygen and temperatures Temp.'C Press. mmflg e[hylene vayl chlorde etkyleoe vayl ehlorde ethylene vnyl chlorde IOLI 2t u >os ,6 Izs x x 3S.I 13.1 X X X S.f x :non-exploson 6) D. E. Houre and A, D. Walsh, Trans. Faraday Soc., a0, 3 (1914)

8 The Revew of Physcal Chemstry of Japan Vol. 29 No. 2 (1959) Studes on Cxplosve Reacton of Vnyl Chlorde mxed xah Oxygen 79 and Che nducton perod at varous constant temperatures for 20 m vnyl chlorde mned wth oxygen. In Table 1, the nducton perods n the exploson pennsula of vnyl chlorde mxed wth oxygen are compared wth 2D;b ethylene mxed wth oxygen. It s nterestng to.say that the exploson pennsula s more restrcted but the nducton perods of the exploson are shorter n [he case of vnyl chlorde than n those of ethylene. In other words, t s consdered that hydrogen chlorde s an nbtor of carbon monoxde combuston but wll eventually be a promoter of the slow reacton of vnyl chlorde. The apparent actvaton energy of the reacton In Fg. 7 s shown the relatonshp 5.8., ' Z ~3 S.G 5.4 t on ^ 5.0 Fg. 7 Logro P/T aganst 1/T curves for the exploson lmt of vnyl chlorde oxygen mxtures Curve I=20%. 2=40%, 3=60%, 4=80% vnyl chlorde 4.8 A.f ]/Tx10' between log PJT and 1 JT for the thrd pressure lmt of Fg. 2. These graphs are essentally lnear a[ a lower temperature than 600 C. Ths corresponds to the relatonshp IogsP/T=AJTtB. The case s smlar to that of ethylene mxed wth oxygen. I[ the thrd pressure lmt s thermal n Table 2 Actvaton energes estmated from the exploson lmts of vnyl chlorde-oxygen mxtures CrHxCI g; E-1.303x 2x 1.98xA (kcal/mole) f

9 The Revew of Physcal Chemstry of Japan Vol. 29 No. 2 (1959) 80 \l. Suga character, the gradent of these lnes.:1, wll be equal to E/2.303 x 2 x R. Thus. values for E, the apparent actvaton energy. may be calculated as n Table 2. By comparson wth the values of ethylene mxed wth oxygen?), t s found that the "E" values of vnyl chlorde mred wth oxygen almost.analogous to those of ethylene. Of course, there wll be no drety meanng n the knetc nterpretaton, but the exploson reacton of vnyl chlorde mxed wth oxygen may apparently be consdered as thermal n nature n ths expermental ranges as n the case of ethylene. Summary The exploson lmt of vnyl chlorde mxed wth oxygen was determned at. reduced pressure by the "admsson method". of gnton flames are shown. Isnchors and so[hertcs of the exploson lmt and also the colors t s consdered that there s no esental dfference between the behavours of tny] chlorde mxed wth oxygen and ethylene mxed wth oxygen except the generaton of hydrogen chlorde under the s'imv reacton. The nducton perods n the exploson pennsula of vnyl chlorde mxed wth oxygen have also been measured and t s found that these values are shorter than those of ethylene mxed wth oxygen. The apparent energy of the reacton s estmated from the exploson lmt of vnyl chlorde mxed wth oxygen accordng to Scmenoff's theory and ts mean value "L " s about 34kcal. The author wshes to thank Prof. R'asaburo Jono. Dr. ]ro Osug and the late Prof. Ryo Kyama for ther knd advsed and encouragement throughout ths work. He s grateful to D4r. Hrom[su -Naono and ~Ir. Junch Rzuk for ther assstances of the obsen atons n part of the present experment. Depart racnt of Chemstry Fatally of Scfeuce aad Lteraftrrc Ehme Ua ~~ers+y.ja(suymna, Japan I,