Initiation and Growth of Butadiene Wesinous Polymers
r .
I tie i p o r i t a n e o u s f o r m a t i o n of a n i n s o ~ i ~ einfii-il>lv , 1,utacliene p o p c o r n pol?;merha$ been e n c o u n t e r e d i n c o ~ i i t . o f Lhe c o m m e r c i a l clibtillation u n i t s w h i c h are ic-etl t o purify butadiene f o r the s?;nthetirr u b b e r proprani. On( t' i n i t i a t e d , the p o l > m e r Shows a l o g a r i t h m i c pro\+t h i t i b u t a d i e n e monomer and has caused fouling and etet] hurstiiig of l a r g e scale distillation e q u i p m e n t i n relatit el? short t i m e s . h l t h o u g h it can be i n i t i a t e d in n %arietyof w a y s , iron and a c t i t e oxygen play a11 i m p o r t a n t p a r t i r i its f o r m a t i o n . Its g r o w t h is retarded b u t n o t t e r m i n a t e d by ~ulcanizationaccelerators, n hereas c.on\eritional ' i n t i oxidants h a v e l i t t l e effect.
i ~ i t ~ t l i y l l ); tut \li t . i i t , ]it~i)woriipolyiiii~rbill the vapor phase, \)illr,:wh polyiiier g c v v only ivheii pl:icetI in the vapors of its oii-11 mono1111'1'. lil,\\.c~vl.r, \\.(' h ho\\.ri that 3odium popcorn piiIyiii(,r( i f tJuta:lit~nc~ ivill grow i i a c i d in liquid 2,8-dirni.th?-li)ii~:i(li~,iii,, :til iidiratioii that rigid sc-liartirity of tht. polynicsi, f o r i t 5 own iiioiiotn(~rt1oi.s not alnxys ( I I T U I ~in t h c i liquid pti:Lpecially ' t h t s rc.:ictor 1i:iti not heen thnri,ughly vlcaiied after a previous run. Thr, popcorn polymvr s1uilic.i r t x -
ly ivith tiutndic~nr~ and not. with hiit:itlir~iie-
s
POXTANEOUS formatioil of a rrsiiiou~piilyinrr of hut n-
diene has h e n encounti1rt.d in born(' of the commercial diytillation units which are usrd t o isolattx and purify butadieiit. for the synthetic rubber program. This phenomenon is of interest t o butadiene manufacturers because this insoluble, infurihle hard polymer not only fouls distillation equipment, but has, in some instances, caused hulgiiig and eve11 splitting of steel COW s. While this type of polymer may occur in several physitee1
Copprr Zinc .\laglietic rrerl Lend Chroii.iuiii
015 014 015 016 016 016 015 014
Vol. 39, No. 7
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Sei-era1 Eriiall ,eed-. fortued Sereral s i r i ~ l seeds l iuriiied Poprorn furtried a n d c i i i ered iron bar 'I'ie. 2
lieiizvyl peruwde uddpd. I'ublkhed rare uf diiiierization u f butadiene T U l-viiiy1-3-ry~luliexene = 0.0lti:; per hour s t 60' c'. ( I ) , . Published r a t e f o r wluble rubbery prJlyri!er forriiation = 0.000'; per hnur at 0 p . p . m . a r r i v e o x y g e n , 0 . 0 2 ' , 20 p.p.ni., 0 . 0 6 5 ' ; iit 100 p . p . m . is!. 0
6
:ai
iitui.1i tliv *:me p a t t c m i'racticdly liiicar vurvoq ( J f i&.iitical .>lopi' ~ v e wobtained when the logarithm of the inais ww plotted
against time. It, is poshible that the apparently faster pron.t.h during tmlwfirst few days was ducb to the amount of hutadicrie required t o saturate physically thc initially liutatiienc-free h ~ i i i i i c s c s growth \vas measured b y volume. of mononicr corisunicd. 0thc.1. fwtors wliivh may have affect,c.dthesc groivth data art' ((ti i q o s u r c . of seed to air Ivhich ip knoivn from other \vvork to havc. t'he rfftirt of reducing th(. init,ial activity of the polyrn Formation of dimer and soluble polynicr in the liquid phase which r c d u c ~ ~the s activity of butadiene ninnoniw availalile to thib swd as thc c~sperinientproceeds. ('ori>idt~ringthat t h r loyarithm of the ma%$in grinvtli viirit.x I i l I l ~ ~ Y \\.it11 ly iiml~. 111 / I '
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thc. folloning iliff(~ri:ntialgron-th tquation:
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HATE OF I'OI'CORN POLYJIEK
l'upcurii p o l y i i ~ of ~ r hutatlitme does not prow at it constwrlt ra t t s in c'untact with monomer but rather propagates at a constaiitly accvli~iatingrate, an indication that additional points of growth arc' continuously formed as the mass increases. Thiu o c c u ~it1 an twmmtt~dsystem nit,h no catalyst other than what might t x b
I'cbtLtintd
ti? t h r ,wid. Since active oxygen, which is necessary
for. t , h t b initiation of popcorn polymer, is not required for it- 5 ~ 1 1 scqucxtit growth, this i> in line with the previously mentic,iicd Cart that sodium popc'o~tt polymer !vi11 grow iu t h r ahwii?(~of
sodium (,5). Figurt' 3 show2 thr. ratc: ui' gl'IJ\\-t.hof two resinous p01yiiit.i. w d s in 1)utndient: vapor a t 60' C. .llthougli tho initial swd\ w w r:tdicaIly diffrrrnt in physical form, the growth followd
0.40
e 0
a
I;'
0.20
0 -1
B
0.10
0.08 :S: 0.06 @
TIME, DAYS
3. (;ro\)th of Popcorn I'ol?iner Seed in 5atnrated Butadiene at 60" C:. without Ox?gen
Figure
d
July 1941
INDUSTRIAL AND ENGINEERING CHEMISTRY
829
T ~ R L I\-. E GROWTHO F BCTADIEXER E h 1 X O I . h P O L Y l i E R IS SITT-R~T Bt-TADIESE F,~ VAPORA T 60" C. AFTER VARIOT-s TRE.4TMEYTS
C:roath IrC ,uf Original irtivity
in JVt, c :L after Day*
'Treating .\genr"
C;
Sunr .Arceleraiiir~a n d 7-ulcanization a g e n t i S u l f u r i n petroleum n a p h t h a \[ethyl t u a d s ( t e t r a m e t h y l t h i u r a n i dizulfidpr 1 . 3 3 g . i n 100 ml.benzene 5 0 g in 100 ml. benzene S n n t o r u r e fbenaothiazyl s u l f o n a m i d e ) . 5 0 e!. i n 100 nil. benzene ( ' a p t a x ~niercaprob~nzothiazole), 5 0 K . in 100 n i l . benzene p-Quinoiie dioxime i n iiopropyl alrohol
.?fin ._.
..
132
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1
Chlorine I v a p o r ) Br. ( 2 ) Itiid., 395, 226 (1913). (3) I l o l t , '1..Z . angeu'. Chem., 27, 150 (19111. 14) Koblynnskii. G . G.. and P i o t r o v s k i i . K. H., Sintct. K a u r h i ~ k . No. 2 , 3-7 (1936). 1.51 K o h l y a m k i i , G . G., and Rokityari~kii,I. \ . , I b < L , K O . 6, 2 - i (19361. 10) K o n d a k o v . I., .J. p r a k t . C'hpm., [ 2 ] 62, 172 (1900). ( 7 ) 51atthew.s. F. E . , and Strange, E. IT.. Brit. P a t e n t 94,700 (Oct. 2 5 , 1910). (8) Roheq-. I
