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The additivity principle in pyrolysis—gas chromatography of brown coal
Jourr.eJ o f Anu.~.-ticcJ and .4pp!ied Pyro/ys;a, 3 (1951"1952) 263--269 Elr,e~-ier Scientific Publiahing Company, Ams~ert~m -- Printed in T h e .~e~e.-Iz=ds
263
THE _~DDITIVITY PRINCIPLE Eq PYROLYSIS--G_kS CHRO.~L-~TOGIL~PHY O F B R O ~ . ~ COAL P.-~VEL ~EBE~"YA and VIKTOR DOBAL lr.$tit,-'te o f GeotogF ~nd Geoteehniquez. C-~ec~.os!o.~ A~--e.~..~" o~ Sc;.er.ees. Y H o ~ i o t ~ k ~ c h 41. 182 09 P r ~ u e ~.Czechodo:~.~:)
JAROSLAV KL:B.'-kT D e p ~ t m e n t o f Coke. Gcs end A i r Protectior.. I r J t i t u t e o f Che.~..-c.'~ T e ~ o S'-'-chb~tcroz'= 5, I 6 6 28 .Pc=~'.~e (Czechos~.c:'=~:.cy
".o~..'.
tReeeh'ed April 10th. 19511 accep*.m! J u n e 19¢3.19S1)
SU-~LMARY P.vzoly~s---gas chromatography o f brown co~l e x h - ' b ~ -ddi~s'e prope~ies ~nd iz therefore possible to construct the p x.-rogr~, o f the oHgi.n-', e o ~ ".'r~m z.he : . n ~ h ~ : ~ pyro~'-_ms o f the bitumen, hurn~e ac'ds, l;gn;.n --_n~ hu.-n.L-. fr~c~'o:.s. "l~-..e c o n : e n ~ o f phenols in the p>'rograms are typi~_.,l for ~l] o f "he zboTe c;-..sse$ excep: bi:u.'n.en. -_rid ~_~e in agreemen: with the eontenr.s o f ~he indh'~du~ groups in zhe origL---..-.ic o a l .-r~.e re~-.:'.':s s'-ggest th:tt the separ'~tion does n o t b.'~.ng - - b o u t s ; . g r . i ~ - . n t ehem:,r.~-.] e.h~..n~'.es in =-.,'.d;-~'=~-'-"--.] bro~.-n co-.d frffiet]o.-.s.
LNTRODUCTION C o a l is a s e d i m e n t a ~ . - m ; n e r a l f o r m e d b y t h e a c c u m - 1 ~ f i o n o f ors~_noge.~.;c rn=~s u n d e r f a v o u r a b l e c o n d i t i o r L s . T h e b a s i c c o m p o n e n t s a r e ".he d o m i n z n t v e g e t a t i o n a n d l o w e r a n i m a l o r g a n i s m s a t t h e t i m e o f t_he o r ; . ~ n o f c o a l ~ [ 1 ] . T h e p r o c e s s o f c o a l i f i c a t i o n is a c c o m p a n i e d b y h o m o g e n ~ _ t i o n of the origin~y considerably heterogeneous coal m~. With bross~ coals, where t h i s p r o c e s s o c c u r r e d t o a l e s s e r e x t e n t , it is r e l a t i v e l y ea~.- t o d i s t i n g u i s h i n d i v i d u a l s t r u c t u r a l u n i t s . _~larcusson anal.v.~s [ 2 ] m a k e s it p o s s i b l e t o s e p a r a t e t h e ~ r ~ p l e ~ a x e s , r e s i n s , h u m i c a n d fat~." a c i d s , h u m i n s , lignLn, a n d cellulose present in a brown coal, and it has been used in our work with the aim o f a s c e r ~ q ; n i n g t h e b e h a ~ - i o u r o f t h e i n d i s - i d u a l f r a c t i o n s u n d e r p.~-ro~-.~--gzs c h r o m a t o g r a p h i c ( P y - - G C ) c o n d i t i o n s f r o m t h e s-:ewpoi.nt o f t h e i r inte.--act i o n . I f t h e s e p a r a t i o n p r o c e s s e m p l o y e d l e a d s o n l y t o t h e cleas-age o f b o n d s t h a t a r e w e a k e r t h a n t h e c o ~ m l e n t c h e m ; r = ] b c n d s , i t is p ~ s s i b l e , u n d e r c e r tain conditions, to anticipate the independent beha~-iour of the individual
f~act~.ons.
0165"2370J82.-'0000--0000!$02.75 ~ 1952 ~.se~ier Scientific Pub'-;.ir,h;.ng Comp~.ny
264 EXPERI.MENT-AL All o f t h e results given r e l a t e t o s a m p l e s o f West B o h e m i a n x y l i t i c coal ~ i t h an ash c o n t e n t o f 3.03 ~-t..~ o f t h e t o t a l solids, a c a r b o n c o n t e n t o f T1.45~¢ a n d a h y d r o g e n c o n t e n t o f 6 . 1 1 ~ o n a d r y ash-free basis. T h e c o n t e n t o f ~rater ~ras 26.31 wt.%. F o r g r o u p s e p a r a t i o n a c c o r d i n g t o Marcusson, 1 3 0 g o f coal w e r e used. B i t u m e n , i.e.. w a x e s a n d resins, was s e p a r a t e d b y e x t r a c t i o n w i t h 3 0 0 m l o f ~-._-bon tet_,-achloride in a Gr3fe e x t r a c t o r f o r 8 h. Waxes w e r e n o t s e p a r a t e d f r o m reMns. T h e e x t r a c t e d coal x ~ s d i g e s : e d w i t h a m m o n i a s o l u t i o n a n d free h u m i c avids :-.-~._~.p r e c i p i t a t e d f r o m t h e s o l u t i o n w i t h 0.5 . \ ' h y d r o c h ! o r ~ c acid t o a pH o f 4.9 ( i n d i c a t e d b y m e t h y l orange). T h e solid r e s i d u e ~-as t h e n t r e a t e d w i t h 17-. s o d i u m h y d r o x i d e s o l u t i o n irl a w a t e r - b a t h f o r 1 h. This o p e r a t i o n faci.Titated t h e tr~qsfer o f f a t t y acids a n d b o n d e d h u m i c acids i n t o s o l u ~ o n Ln ~i:e f o r m o f t h e ~ s o d i u m salts. T h e a c i d ~ c a t i o n w i t h 0.5 .\" h y d r o c h l o r i c acid m a d e it p o s ~ b l e t o p r e c i p i t a t e h u m i c acids w h ~ e f a t t y acids r e m a i n e d in ~b.e s o l u t i o n . T h e cellulose was t.mnsferred f r o m s o d i u m hydroxide~_nsolu b l e .-x*s"due i n t o tht* s o l u t i o n w i t h 1 0 0 m! o f 3 6 ~ h y d r o c h l o r i c acid. "l-he L-,.soluble r e m a i n d e r , cont-~:-ning humL~.s, ~,~shes a n d lignin, was f u s e d w i t h resoxx-ino! at 1 7 0 : C for 10 m i n a n d t h e m e l t was d i g e s t e d w i t h e t h a n o l . L"gnL'~ p~ssed i n t o t h e s o l u t i o n a n d t h e L-~soluble pa.~ c o n t a i n e d h u m i n s a.,-.d ashes. T h e s a m p l e s sep-~,-ated in this w a y a n d t h e ~ . m p ! e o f t h e original coal w e r e s u b j e c t e d ~o p y r o l y s ~ in t h e a p p a r a t u s d e s c r i b e d b y R o m o v S ~ e k a n d Kub-~t [ 3 ] . co,--.~.in.~ o f a quarzz r e a c t o r w i t h a m o l t e n t i n b a t h h e a t e d t o 5 7 5 : C . L'v.der s',-,ch c o n d i t i o n s it .~:-possible t o e s t i m a t e t h e s p e e d o f t e m p e r a t u r e rise as ca. 35=C - s - : T h e s a m p l e was w e i g h e d i n t o a h o ~ o w t i n c y l i n d e r wb2ch ~,_s closed by a s m ~ l tL-x plug and fed by an e!ectromag~.etic doser ~_nto the moi.=en bath. T n ~ procedure facilitated a se~es of ~-talyses without interrupt!on o f t h e stream, o f c~Jr':er ~,..,. "une a p p r o x i m a t e s a m p l e sizes w e r e ca. 3 rag f o r coal a n d h u m i n s , 1--2 m g f o r h u m i c acids a n d lignin a n d ca. 0.5 m g f o r bitumen. "Use pyro!ys'-:s p r o d u c t s w e r e s e p a r a t e d o n a 2.5 m X 3 m m I.D. c o l u m n p a c k e d ~s-ith 2 0 ~ DC 2 0 0 o n C h r o m o s o r b P A W ( ~ 0 - - 1 0 0 m e s h ) . T h e car~:er g~,.s ~xts n i t r o g e n at a flow-rate o f 3 0 m l - r a i n - ' . T h e c o l u m n t e m p e r a t u r e was p r o g r a m m e d f r o m 4 0 t o 200=C at 5 " C - rain -t a n d t h e indi~-idual p e a k s w e r e ~_ntegrated w i t h a.n SP 4 1 0 0 c o m p u t i n g i n t e g r a t o r .
R ~ U L T S .AND DISCUSSION T h e results o f t h e M a r c u ~ 0 n g r o u p s e p a r a t i o n are given in T a b l e 1. T h e y i e l d o f cellulose a n d fat~- acids ~-as v e ~ - l o w (ca. 0 . I ~ ) . . M o r e o v e r , t h e f a t t y acid f r a c t i o n y i e l d e d a ve~- p o o r p y r o g r a m t h a t d i d n o t c o r r e s p o n d t o organic ~abstances. A sp_~ctral analysis i n d i c a t e d t.b.~t over 50-% o f this fract i o n w.~ f o r m e d b y inorganic s u b ~ a n c e s , c o n t a i n i n g m a i n l y -~a, K, Ca,.-~lg, _-Xl, Si, F e , etc. For the other fraction, two types of pyrograms were recorded. They differ
265 TABLE
1
Rezults of .Ma.,~"',~uona.,-.~lyslsof brown co~. w~.~ on a c!~"sz..,=p:e b ~ B,:-.u m e n
Hur:'.3cacids FR~ty acids L~gnLn Humins + -..Lh
1.41
10.76 0.49 I0.67 T6.67
f r o m each o t h e r in t h e p r e s e n c e o r a b s e n c e o f a m ~ o r p e a k ~ h a r e t e n t i o n t i m e o f ca. 3 8 m i n (see Figs. 1 a n d 2). P , ~ k R was p r e s e n t ov.ly in t h e s a m p l e o f lignin a n d h u r n ; n s a n d ~ - ~ a b s e n t in t h e s p e c n ' a m o f t h e or~gin~ c o N . F r o m t h e p y r o g r a m o f r e s o r c i n o ! (Fig. 2c) it ;.s c o n c l u d e d thaz ~his p e a k ;.s resorcinol, w h i c h ~ u s e d f o r ~he s e p a r a t i o n c f ]i~.Ln ~ o m hum;_,,_$. FiE- 2c also s h o w s t h a r m o ~ o f t h e r e s o r c i n o l r e m a i n e d u n c h a n g e d . R e s o r c ! n o l p.vro~'~s released o n l y 12.9 wL.~ o f p h e n o l a n d 11.1 ~ _ . ~ o f o t h e r p r o d u c t s (de~erm;_ned b y c o m p a r i s o n ~rith t h e direc~ ges c.hroma~ographic analysis o f s t a n d a r d m i x t u r e s o f p h e n o l a n d r e s o r c i n o ! ) . A f u r [ h e r comp~_~_son o f t h e p e a k area o f r e s o r c i n o l in lignLn a n d h u m i n s w i t h tha-. f o r a kno~.-n a m o u n t o f r e s o r c i n o l s h o w e d tha~ 11.5 w t . ~ o f r e s o r c i n o ! r e m a i n e d Lu !ignin a n d 9.6 wt.-.~ in hum~-.s. T h e i d e n t i f i c a t i o n o f t h e h-;dividu~ c o m p o n e n t s Lu ~he p.~Togrm-ns was irrelevant f o r t h e o b j e c t i v e s o f this stud.v..~evertheT-ess, T~o!e 2 i n d i c a : e s ~he possible p r o d u c t s o f pTrolysis t h a t w e r e i n f e r r e d f r o m ~he r e ~ n ~ i o n t i m e s o f p u r e c o m p o u n d s o r f r o m t h e o b s e r v e d increase in cer-w.in p ~ . k s f o ~ o w i n g t h e a d d i t i o n o f a u t h e n t i c c o m p o u n d s t o t h e .~.mple b e f o r e P y - - G C ~--.z!vs~.s. I n mos~ instances rn~,ced p e a k s are p r o b a b l y involved. F o r ~he ~.'pha-:ic hyd.rocarbons, which are prevalent in the bitumen spec~n~m [4], ~ e compos!;ion according zo the n u m b e r of carbon a-.o--~ in zheir mo!e~.-,!es ~ as -_'o~o~: peaks 1 and 2 correspond to the area hu C~.e p.~-ro~rm-ns r.ha~ belong xo C~, peaks 4---7 to C~, peaks S--12 zo C~, pea.ks 13--16 to C-.,pe-~ks 17--20 :o C,, .ue~
266 -~
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Fig. 1. P:,_-rograms o f (a:. 2.95 mg o f original coal, (b) 0.57 mg of bitumen and (c) 2.06 ~_.g of hu-~.;.c acid.s.
t i o n d e t e r m i n e s t h e c h a r a c t e r o f a/l p3-rograms o w i n g t o its incomplete e x t r a c t i o n f r o m t h e o t h e r f r a c t i o n s . T h i s a p p l i e s e s p e o i u ] l y t o t h o s e parts o f t h e sp. e c ~ m w h i c h p _ , ~ u m a b l y c o n t a i n o n l y a l i p h a t i c h y d r o c a r b o n s ( e . g . , g r o u p o f p e a k s 4--8). P r o n o u n c e d q u a n t i t a t i v e d i f f e r e n c e s are n o t i c e a b l e , h o w e v e r , f o r p e a k s t h a t are p r o b a b l y p h e n o l s ( p ~ k ~ 2 6 a n d 3 0 ) . . M o l - e o v ~ , t h e b i t u m e n s p e c t r u m l a c k s p e a k 3 4 , w h i c h is p r e s e n t in all o t h e r s p e c t r a a n d represents m- and p-ethylphenoL The contribution of each fraction to the i n d i , A d - ~ 1 p ~ "~s o f t h e c o m p o s i t e w a s c~Icular~,d f r o m T a b l e 3 a n d is s h o ~ , ~
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Fi~. 2. l~-rogr~_~.s o f (a) 3.22 mg of hu,~:-~so ~b) 1.26 ~-~ o f l i ~ z~sorc.;nol.
-',".d (c) 0.35 m~ of
in Table 4, which also gives, for the sake of comparison, abund~_,~ces of tb.e coal fractions. Bitumen accounts very" markedly for L~.eabIL~dP.nce of h y d r o c~rbons in the finalrecord. Further interesting circumstances are revee.led on com_~.,ing the ,~lues obtained by .Max~,~-on analysis with those acquired for phenol (pe~-~ 26 in Table 4) and its derh~tth-es(pes~e 29, 30. 33 and 34). It appears that pheno~ constitute the basic structural units in hum~e acids, lignin a.ud humins and are t h e t 3 ~ i c a l p3~'olysis p r o d u c t s . "Fne p r e s e n c e o f p h e n o l s i n s ~ c h c o a l ~--actions, in accordance with the assertions by Flaig [5] and Adier [6], ,vho regard lignin as a po!yphenol, is fox---ed by phen,'Ip.~pane de~s~th-es of the
26S TABLE 2 Qualitative composition of pyrogran~ P e a k .N'o.
Compounds 1-Pentene n-Pentane 2-Me~.hylpentane l-Hexene r. -Hex~,-.e C~-elohexane, 2 , 2 , 3 - ¢ r i m e t h y l b u t a n e , 2 , 4 - d i m e t h y l p e n t a n e Benzene 1-Hep:ene n-Heptane Methylcyclohexane, dirne~hy!hexane 1-Oclene, t o l u e n e
4 5 9
10 13 14 15 16 1-
n-Oc~a.~.e 2,2,5-Trimer.hylbexane m-, p-XFIene, e=hy|~enzene
2O 23 24 26
o-Xy!e=e, 1-nonene Phenol, pse".documene l-Decene
p-Cymene, o-c.,'eso!
29 30 31 32 33 34
m.-. p - C r e s o l l - L ' n d e c e n e . 2,6-c!irneLhylphenol o-E~hylpher.ol 2,4-, 2 , 5 - D i m e t h y l p h e n o l m-, p-Ec~.ylpheno!
TABLE 3 P e a k :~eas f o r brov,'n co~'- .fr=,-c_:='o.'-.s.. adjt~s:e~ ~or the" m a s s presen~ ,n" t h e oHg:.nal co-,~_. sa.-np!e ( i n t e g ~ t i o n u n i t s ) Peak No.
B'::,'men
Iium':e acids
5 13 14
1")61 .86 3"-,.<-z)
436 400 1059
1~
223;
14~36
23 24
1131 873
;'29 445
Z'~o
414
2749
H,'.-n;..,,.s
°5~S 1778 6331
Lgnin
1351 $93 3905 "
coal
Difference (~)
5";36 3~57 14,270
6413 3863 12,T70
--10.6 --0.2 +I!.8
2 -~
720
593
29
194
695
5671
30
425
2604
33
235
602
4145
447
5429
5596
--3.0
34
0
484
")578
896
3958
3883
+1.9
* *
17.900 17,350 *
,t
O~gi.'-.:d
l~ro=:ps
5379 7435 6975 3655 2841 2597 32,786 22,137 3909
*
1$6..~ 3143 2588 1533 1037 865 5~71 3764 1409
Sum of
"
" '~
1040 2828 2 1 6 9 '~
1R.178 14,304 13,286 .047 5154 4883 4] ,820 29,064 6631
~603
~r 13,612 " .120 4336 * 28,211 * 6238
8356
23,760 20,660 2 2 , 5 5 1 '~
= ~,'al._.es a d ] u s : e d t o t h e pyr.olys!s p r o d u c t s o f rer,o r c i n o l .
---4.6 * +5.1 --2.4 * --1.0 "18.9 + 1 2 . 0 ,t +48.2 +3.0 * +6.3
--9.0 +15.0 +9.2 *
269
TABLE 4 ShL-e o,* individual f r a c t i o n s in t h e overall p.~.-rogr.a_,n(%) Peak No.
Bitumen
Humic a~d~
Hu.~. ;..-.s
Li~n..L,~
5 13
22.0 20.3
T.$ 10.4
46.9 46.1
~3 6 23.2
14
31.S
1S 23 24 26 2~ 29 30 33 34
16.S 16.0 1T.9 1.4 10.9 2.6 1.9 4.3
.Or~,~inal coal
44.2
15.3
0.0
11.2 10.3 9.2 9.5 S.9 9.2 11.5 11.2 12.3
S.-1
5°-.5 51.2 55.2 ":6 . 2 55.9 ~'4.5 76.9 :6.3 65.1
1-~.4 21.8 1T.-1 ! 3.0 21.3 13..-~.6 S.2 22.6
1.4
10.8
76.T
! 0.T
coniferyl, sinapyl and p-coumaryl zype of ~coho!. Indi,~:du~ benzene .~.~.~s in lignin are ;linked by ether bonds or by c'e.rbon--c~bon bonds ~izh ~iphztic, hydroxyl and methoxyl side-chains [6]. A similar s:r-~c'.urecan ~ o be found in humic acids [7]. T h e i n d i v i d u a l c o m p o u n d s f o u n d i n p y - r o g r a r n s ~ . n o~.gina~e ei*:~.er f r o m m o l e c u l e s f o r m e d b y t h e r m a l s c i s s i o n o f o r i g i n a l b o n d s L-I t.he m~_cromo'..ec u l e s i n c o a l , o r f r o m t h e s t a b i l i z a t i o n o f l~Toly-=is-forrned radic-,~s o n t h e basis o f t h e i r r e c o m b i n a t i o n i n t h e gas p h a s e . Judgh=.g f r o m t h e a b o v e r e s u l t s ,
r.hefor~ler a l ~ t i ~ - e appears to be operative. This opLnion is furt,her backed by the possibilityof determining sequence distributionsL'~~rio'-~sc o p o l y m e ~ ~]th the help of Py--GC, e.g. see ref. 8. T h e inzerpre+.~on of the re.~.dzs pertaining to the fo.,,,ation of dimez~ and t~_mers from copo!ymer chains i m p l i e s a l o w p r o b a b i l i t y t h a t t h e i r origLn lies i n r~combh~.a~.ion Ln t h e gas phase.
REFERF-~CES
1 2 3 -~ 5 6 T
D.W. van Krevelen, Coal Science, Els~-ier, A.--..s'~.-xiam, 1 9 6 : , 7- ~,5. J- ~-M~-rcu~on,Z. o~agew. Che..-n., 40 (192"i) 1104. J. Romo%~i6ek and J. Kubit, .Anal. Chem., 40 (1965) !119. V. VC-ela~, J. Kub~t and V. Dolml, Fec~e, SeiEen, .A-,~-~~c~__~.,.--5 (1972:, 2T~. W. Fla]g, Geochim. Casmoc.hL, n. Acta, 2S (1964) 1 5 2 3 . E. Adler, Z. Papieer, 15 (1961) 604. BE. Cooper and D.G. Murchison, in G. Eglinzon and M.T.J. 5t.u.--phy (Ed~=o.~), O = ~ c Geoche~,;¢try, S;~inger, Heidelberg, 1969, p. 699. $ "1"..~agaya, Y. Sugh---ura and S. T ~ g e , A~z=~-,,o!ec--"-e~, 13 (1950) 3 5 3 .
263
THE _~DDITIVITY PRINCIPLE Eq PYROLYSIS--G_kS CHRO.~L-~TOGIL~PHY O F B R O ~ . ~ COAL P.-~VEL ~EBE~"YA and VIKTOR DOBAL lr.$tit,-'te o f GeotogF ~nd Geoteehniquez. C-~ec~.os!o.~ A~--e.~..~" o~ Sc;.er.ees. Y H o ~ i o t ~ k ~ c h 41. 182 09 P r ~ u e ~.Czechodo:~.~:)
JAROSLAV KL:B.'-kT D e p ~ t m e n t o f Coke. Gcs end A i r Protectior.. I r J t i t u t e o f Che.~..-c.'~ T e ~ o S'-'-chb~tcroz'= 5, I 6 6 28 .Pc=~'.~e (Czechos~.c:'=~:.cy
".o~..'.
tReeeh'ed April 10th. 19511 accep*.m! J u n e 19¢3.19S1)
SU-~LMARY P.vzoly~s---gas chromatography o f brown co~l e x h - ' b ~ -ddi~s'e prope~ies ~nd iz therefore possible to construct the p x.-rogr~, o f the oHgi.n-', e o ~ ".'r~m z.he : . n ~ h ~ : ~ pyro~'-_ms o f the bitumen, hurn~e ac'ds, l;gn;.n --_n~ hu.-n.L-. fr~c~'o:.s. "l~-..e c o n : e n ~ o f phenols in the p>'rograms are typi~_.,l for ~l] o f "he zboTe c;-..sse$ excep: bi:u.'n.en. -_rid ~_~e in agreemen: with the eontenr.s o f ~he indh'~du~ groups in zhe origL---..-.ic o a l .-r~.e re~-.:'.':s s'-ggest th:tt the separ'~tion does n o t b.'~.ng - - b o u t s ; . g r . i ~ - . n t ehem:,r.~-.] e.h~..n~'.es in =-.,'.d;-~'=~-'-"--.] bro~.-n co-.d frffiet]o.-.s.
LNTRODUCTION C o a l is a s e d i m e n t a ~ . - m ; n e r a l f o r m e d b y t h e a c c u m - 1 ~ f i o n o f ors~_noge.~.;c rn=~s u n d e r f a v o u r a b l e c o n d i t i o r L s . T h e b a s i c c o m p o n e n t s a r e ".he d o m i n z n t v e g e t a t i o n a n d l o w e r a n i m a l o r g a n i s m s a t t h e t i m e o f t_he o r ; . ~ n o f c o a l ~ [ 1 ] . T h e p r o c e s s o f c o a l i f i c a t i o n is a c c o m p a n i e d b y h o m o g e n ~ _ t i o n of the origin~y considerably heterogeneous coal m~. With bross~ coals, where t h i s p r o c e s s o c c u r r e d t o a l e s s e r e x t e n t , it is r e l a t i v e l y ea~.- t o d i s t i n g u i s h i n d i v i d u a l s t r u c t u r a l u n i t s . _~larcusson anal.v.~s [ 2 ] m a k e s it p o s s i b l e t o s e p a r a t e t h e ~ r ~ p l e ~ a x e s , r e s i n s , h u m i c a n d fat~." a c i d s , h u m i n s , lignLn, a n d cellulose present in a brown coal, and it has been used in our work with the aim o f a s c e r ~ q ; n i n g t h e b e h a ~ - i o u r o f t h e i n d i s - i d u a l f r a c t i o n s u n d e r p.~-ro~-.~--gzs c h r o m a t o g r a p h i c ( P y - - G C ) c o n d i t i o n s f r o m t h e s-:ewpoi.nt o f t h e i r inte.--act i o n . I f t h e s e p a r a t i o n p r o c e s s e m p l o y e d l e a d s o n l y t o t h e cleas-age o f b o n d s t h a t a r e w e a k e r t h a n t h e c o ~ m l e n t c h e m ; r = ] b c n d s , i t is p ~ s s i b l e , u n d e r c e r tain conditions, to anticipate the independent beha~-iour of the individual
f~act~.ons.
0165"2370J82.-'0000--0000!$02.75 ~ 1952 ~.se~ier Scientific Pub'-;.ir,h;.ng Comp~.ny
264 EXPERI.MENT-AL All o f t h e results given r e l a t e t o s a m p l e s o f West B o h e m i a n x y l i t i c coal ~ i t h an ash c o n t e n t o f 3.03 ~-t..~ o f t h e t o t a l solids, a c a r b o n c o n t e n t o f T1.45~¢ a n d a h y d r o g e n c o n t e n t o f 6 . 1 1 ~ o n a d r y ash-free basis. T h e c o n t e n t o f ~rater ~ras 26.31 wt.%. F o r g r o u p s e p a r a t i o n a c c o r d i n g t o Marcusson, 1 3 0 g o f coal w e r e used. B i t u m e n , i.e.. w a x e s a n d resins, was s e p a r a t e d b y e x t r a c t i o n w i t h 3 0 0 m l o f ~-._-bon tet_,-achloride in a Gr3fe e x t r a c t o r f o r 8 h. Waxes w e r e n o t s e p a r a t e d f r o m reMns. T h e e x t r a c t e d coal x ~ s d i g e s : e d w i t h a m m o n i a s o l u t i o n a n d free h u m i c avids :-.-~._~.p r e c i p i t a t e d f r o m t h e s o l u t i o n w i t h 0.5 . \ ' h y d r o c h ! o r ~ c acid t o a pH o f 4.9 ( i n d i c a t e d b y m e t h y l orange). T h e solid r e s i d u e ~-as t h e n t r e a t e d w i t h 17-. s o d i u m h y d r o x i d e s o l u t i o n irl a w a t e r - b a t h f o r 1 h. This o p e r a t i o n faci.Titated t h e tr~qsfer o f f a t t y acids a n d b o n d e d h u m i c acids i n t o s o l u ~ o n Ln ~i:e f o r m o f t h e ~ s o d i u m salts. T h e a c i d ~ c a t i o n w i t h 0.5 .\" h y d r o c h l o r i c acid m a d e it p o s ~ b l e t o p r e c i p i t a t e h u m i c acids w h ~ e f a t t y acids r e m a i n e d in ~b.e s o l u t i o n . T h e cellulose was t.mnsferred f r o m s o d i u m hydroxide~_nsolu b l e .-x*s"due i n t o tht* s o l u t i o n w i t h 1 0 0 m! o f 3 6 ~ h y d r o c h l o r i c acid. "l-he L-,.soluble r e m a i n d e r , cont-~:-ning humL~.s, ~,~shes a n d lignin, was f u s e d w i t h resoxx-ino! at 1 7 0 : C for 10 m i n a n d t h e m e l t was d i g e s t e d w i t h e t h a n o l . L"gnL'~ p~ssed i n t o t h e s o l u t i o n a n d t h e L-~soluble pa.~ c o n t a i n e d h u m i n s a.,-.d ashes. T h e s a m p l e s sep-~,-ated in this w a y a n d t h e ~ . m p ! e o f t h e original coal w e r e s u b j e c t e d ~o p y r o l y s ~ in t h e a p p a r a t u s d e s c r i b e d b y R o m o v S ~ e k a n d Kub-~t [ 3 ] . co,--.~.in.~ o f a quarzz r e a c t o r w i t h a m o l t e n t i n b a t h h e a t e d t o 5 7 5 : C . L'v.der s',-,ch c o n d i t i o n s it .~:-possible t o e s t i m a t e t h e s p e e d o f t e m p e r a t u r e rise as ca. 35=C - s - : T h e s a m p l e was w e i g h e d i n t o a h o ~ o w t i n c y l i n d e r wb2ch ~,_s closed by a s m ~ l tL-x plug and fed by an e!ectromag~.etic doser ~_nto the moi.=en bath. T n ~ procedure facilitated a se~es of ~-talyses without interrupt!on o f t h e stream, o f c~Jr':er ~,..,. "une a p p r o x i m a t e s a m p l e sizes w e r e ca. 3 rag f o r coal a n d h u m i n s , 1--2 m g f o r h u m i c acids a n d lignin a n d ca. 0.5 m g f o r bitumen. "Use pyro!ys'-:s p r o d u c t s w e r e s e p a r a t e d o n a 2.5 m X 3 m m I.D. c o l u m n p a c k e d ~s-ith 2 0 ~ DC 2 0 0 o n C h r o m o s o r b P A W ( ~ 0 - - 1 0 0 m e s h ) . T h e car~:er g~,.s ~xts n i t r o g e n at a flow-rate o f 3 0 m l - r a i n - ' . T h e c o l u m n t e m p e r a t u r e was p r o g r a m m e d f r o m 4 0 t o 200=C at 5 " C - rain -t a n d t h e indi~-idual p e a k s w e r e ~_ntegrated w i t h a.n SP 4 1 0 0 c o m p u t i n g i n t e g r a t o r .
R ~ U L T S .AND DISCUSSION T h e results o f t h e M a r c u ~ 0 n g r o u p s e p a r a t i o n are given in T a b l e 1. T h e y i e l d o f cellulose a n d fat~- acids ~-as v e ~ - l o w (ca. 0 . I ~ ) . . M o r e o v e r , t h e f a t t y acid f r a c t i o n y i e l d e d a ve~- p o o r p y r o g r a m t h a t d i d n o t c o r r e s p o n d t o organic ~abstances. A sp_~ctral analysis i n d i c a t e d t.b.~t over 50-% o f this fract i o n w.~ f o r m e d b y inorganic s u b ~ a n c e s , c o n t a i n i n g m a i n l y -~a, K, Ca,.-~lg, _-Xl, Si, F e , etc. For the other fraction, two types of pyrograms were recorded. They differ
265 TABLE
1
Rezults of .Ma.,~"',~uona.,-.~lyslsof brown co~. w~.~ on a c!~"sz..,=p:e b ~ B,:-.u m e n
Hur:'.3cacids FR~ty acids L~gnLn Humins + -..Lh
1.41
10.76 0.49 I0.67 T6.67
f r o m each o t h e r in t h e p r e s e n c e o r a b s e n c e o f a m ~ o r p e a k ~ h a r e t e n t i o n t i m e o f ca. 3 8 m i n (see Figs. 1 a n d 2). P , ~ k R was p r e s e n t ov.ly in t h e s a m p l e o f lignin a n d h u r n ; n s a n d ~ - ~ a b s e n t in t h e s p e c n ' a m o f t h e or~gin~ c o N . F r o m t h e p y r o g r a m o f r e s o r c i n o ! (Fig. 2c) it ;.s c o n c l u d e d thaz ~his p e a k ;.s resorcinol, w h i c h ~ u s e d f o r ~he s e p a r a t i o n c f ]i~.Ln ~ o m hum;_,,_$. FiE- 2c also s h o w s t h a r m o ~ o f t h e r e s o r c i n o l r e m a i n e d u n c h a n g e d . R e s o r c ! n o l p.vro~'~s released o n l y 12.9 wL.~ o f p h e n o l a n d 11.1 ~ _ . ~ o f o t h e r p r o d u c t s (de~erm;_ned b y c o m p a r i s o n ~rith t h e direc~ ges c.hroma~ographic analysis o f s t a n d a r d m i x t u r e s o f p h e n o l a n d r e s o r c i n o ! ) . A f u r [ h e r comp~_~_son o f t h e p e a k area o f r e s o r c i n o l in lignLn a n d h u m i n s w i t h tha-. f o r a kno~.-n a m o u n t o f r e s o r c i n o l s h o w e d tha~ 11.5 w t . ~ o f r e s o r c i n o ! r e m a i n e d Lu !ignin a n d 9.6 wt.-.~ in hum~-.s. T h e i d e n t i f i c a t i o n o f t h e h-;dividu~ c o m p o n e n t s Lu ~he p.~Togrm-ns was irrelevant f o r t h e o b j e c t i v e s o f this stud.v..~evertheT-ess, T~o!e 2 i n d i c a : e s ~he possible p r o d u c t s o f pTrolysis t h a t w e r e i n f e r r e d f r o m ~he r e ~ n ~ i o n t i m e s o f p u r e c o m p o u n d s o r f r o m t h e o b s e r v e d increase in cer-w.in p ~ . k s f o ~ o w i n g t h e a d d i t i o n o f a u t h e n t i c c o m p o u n d s t o t h e .~.mple b e f o r e P y - - G C ~--.z!vs~.s. I n mos~ instances rn~,ced p e a k s are p r o b a b l y involved. F o r ~he ~.'pha-:ic hyd.rocarbons, which are prevalent in the bitumen spec~n~m [4], ~ e compos!;ion according zo the n u m b e r of carbon a-.o--~ in zheir mo!e~.-,!es ~ as -_'o~o~: peaks 1 and 2 correspond to the area hu C~.e p.~-ro~rm-ns r.ha~ belong xo C~, peaks 4---7 to C~, peaks S--12 zo C~, pea.ks 13--16 to C-.,pe-~ks 17--20 :o C,, .ue~
266 -~
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Fig. 1. P:,_-rograms o f (a:. 2.95 mg o f original coal, (b) 0.57 mg of bitumen and (c) 2.06 ~_.g of hu-~.;.c acid.s.
t i o n d e t e r m i n e s t h e c h a r a c t e r o f a/l p3-rograms o w i n g t o its incomplete e x t r a c t i o n f r o m t h e o t h e r f r a c t i o n s . T h i s a p p l i e s e s p e o i u ] l y t o t h o s e parts o f t h e sp. e c ~ m w h i c h p _ , ~ u m a b l y c o n t a i n o n l y a l i p h a t i c h y d r o c a r b o n s ( e . g . , g r o u p o f p e a k s 4--8). P r o n o u n c e d q u a n t i t a t i v e d i f f e r e n c e s are n o t i c e a b l e , h o w e v e r , f o r p e a k s t h a t are p r o b a b l y p h e n o l s ( p ~ k ~ 2 6 a n d 3 0 ) . . M o l - e o v ~ , t h e b i t u m e n s p e c t r u m l a c k s p e a k 3 4 , w h i c h is p r e s e n t in all o t h e r s p e c t r a a n d represents m- and p-ethylphenoL The contribution of each fraction to the i n d i , A d - ~ 1 p ~ "~s o f t h e c o m p o s i t e w a s c~Icular~,d f r o m T a b l e 3 a n d is s h o ~ , ~
267 J|
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Fi~. 2. l~-rogr~_~.s o f (a) 3.22 mg of hu,~:-~so ~b) 1.26 ~-~ o f l i ~ z~sorc.;nol.
-',".d (c) 0.35 m~ of
in Table 4, which also gives, for the sake of comparison, abund~_,~ces of tb.e coal fractions. Bitumen accounts very" markedly for L~.eabIL~dP.nce of h y d r o c~rbons in the finalrecord. Further interesting circumstances are revee.led on com_~.,ing the ,~lues obtained by .Max~,~-on analysis with those acquired for phenol (pe~-~ 26 in Table 4) and its derh~tth-es(pes~e 29, 30. 33 and 34). It appears that pheno~ constitute the basic structural units in hum~e acids, lignin a.ud humins and are t h e t 3 ~ i c a l p3~'olysis p r o d u c t s . "Fne p r e s e n c e o f p h e n o l s i n s ~ c h c o a l ~--actions, in accordance with the assertions by Flaig [5] and Adier [6], ,vho regard lignin as a po!yphenol, is fox---ed by phen,'Ip.~pane de~s~th-es of the
26S TABLE 2 Qualitative composition of pyrogran~ P e a k .N'o.
Compounds 1-Pentene n-Pentane 2-Me~.hylpentane l-Hexene r. -Hex~,-.e C~-elohexane, 2 , 2 , 3 - ¢ r i m e t h y l b u t a n e , 2 , 4 - d i m e t h y l p e n t a n e Benzene 1-Hep:ene n-Heptane Methylcyclohexane, dirne~hy!hexane 1-Oclene, t o l u e n e
4 5 9
10 13 14 15 16 1-
n-Oc~a.~.e 2,2,5-Trimer.hylbexane m-, p-XFIene, e=hy|~enzene
2O 23 24 26
o-Xy!e=e, 1-nonene Phenol, pse".documene l-Decene
p-Cymene, o-c.,'eso!
29 30 31 32 33 34
m.-. p - C r e s o l l - L ' n d e c e n e . 2,6-c!irneLhylphenol o-E~hylpher.ol 2,4-, 2 , 5 - D i m e t h y l p h e n o l m-, p-Ec~.ylpheno!
TABLE 3 P e a k :~eas f o r brov,'n co~'- .fr=,-c_:='o.'-.s.. adjt~s:e~ ~or the" m a s s presen~ ,n" t h e oHg:.nal co-,~_. sa.-np!e ( i n t e g ~ t i o n u n i t s ) Peak No.
B'::,'men
Iium':e acids
5 13 14
1")61 .86 3"-,.<-z)
436 400 1059
1~
223;
14~36
23 24
1131 873
;'29 445
Z'~o
414
2749
H,'.-n;..,,.s
°5~S 1778 6331
Lgnin
1351 $93 3905 "
coal
Difference (~)
5";36 3~57 14,270
6413 3863 12,T70
--10.6 --0.2 +I!.8
2 -~
720
593
29
194
695
5671
30
425
2604
33
235
602
4145
447
5429
5596
--3.0
34
0
484
")578
896
3958
3883
+1.9
* *
17.900 17,350 *
,t
O~gi.'-.:d
l~ro=:ps
5379 7435 6975 3655 2841 2597 32,786 22,137 3909
*
1$6..~ 3143 2588 1533 1037 865 5~71 3764 1409
Sum of
"
" '~
1040 2828 2 1 6 9 '~
1R.178 14,304 13,286 .047 5154 4883 4] ,820 29,064 6631
~603
~r 13,612 " .120 4336 * 28,211 * 6238
8356
23,760 20,660 2 2 , 5 5 1 '~
= ~,'al._.es a d ] u s : e d t o t h e pyr.olys!s p r o d u c t s o f rer,o r c i n o l .
---4.6 * +5.1 --2.4 * --1.0 "18.9 + 1 2 . 0 ,t +48.2 +3.0 * +6.3
--9.0 +15.0 +9.2 *
269
TABLE 4 ShL-e o,* individual f r a c t i o n s in t h e overall p.~.-rogr.a_,n(%) Peak No.
Bitumen
Humic a~d~
Hu.~. ;..-.s
Li~n..L,~
5 13
22.0 20.3
T.$ 10.4
46.9 46.1
~3 6 23.2
14
31.S
1S 23 24 26 2~ 29 30 33 34
16.S 16.0 1T.9 1.4 10.9 2.6 1.9 4.3
.Or~,~inal coal
44.2
15.3
0.0
11.2 10.3 9.2 9.5 S.9 9.2 11.5 11.2 12.3
S.-1
5°-.5 51.2 55.2 ":6 . 2 55.9 ~'4.5 76.9 :6.3 65.1
1-~.4 21.8 1T.-1 ! 3.0 21.3 13..-~.6 S.2 22.6
1.4
10.8
76.T
! 0.T
coniferyl, sinapyl and p-coumaryl zype of ~coho!. Indi,~:du~ benzene .~.~.~s in lignin are ;linked by ether bonds or by c'e.rbon--c~bon bonds ~izh ~iphztic, hydroxyl and methoxyl side-chains [6]. A similar s:r-~c'.urecan ~ o be found in humic acids [7]. T h e i n d i v i d u a l c o m p o u n d s f o u n d i n p y - r o g r a r n s ~ . n o~.gina~e ei*:~.er f r o m m o l e c u l e s f o r m e d b y t h e r m a l s c i s s i o n o f o r i g i n a l b o n d s L-I t.he m~_cromo'..ec u l e s i n c o a l , o r f r o m t h e s t a b i l i z a t i o n o f l~Toly-=is-forrned radic-,~s o n t h e basis o f t h e i r r e c o m b i n a t i o n i n t h e gas p h a s e . Judgh=.g f r o m t h e a b o v e r e s u l t s ,
r.hefor~ler a l ~ t i ~ - e appears to be operative. This opLnion is furt,her backed by the possibilityof determining sequence distributionsL'~~rio'-~sc o p o l y m e ~ ~]th the help of Py--GC, e.g. see ref. 8. T h e inzerpre+.~on of the re.~.dzs pertaining to the fo.,,,ation of dimez~ and t~_mers from copo!ymer chains i m p l i e s a l o w p r o b a b i l i t y t h a t t h e i r origLn lies i n r~combh~.a~.ion Ln t h e gas phase.
REFERF-~CES
1 2 3 -~ 5 6 T
D.W. van Krevelen, Coal Science, Els~-ier, A.--..s'~.-xiam, 1 9 6 : , 7- ~,5. J- ~-M~-rcu~on,Z. o~agew. Che..-n., 40 (192"i) 1104. J. Romo%~i6ek and J. Kubit, .Anal. Chem., 40 (1965) !119. V. VC-ela~, J. Kub~t and V. Dolml, Fec~e, SeiEen, .A-,~-~~c~__~.,.--5 (1972:, 2T~. W. Fla]g, Geochim. Casmoc.hL, n. Acta, 2S (1964) 1 5 2 3 . E. Adler, Z. Papieer, 15 (1961) 604. BE. Cooper and D.G. Murchison, in G. Eglinzon and M.T.J. 5t.u.--phy (Ed~=o.~), O = ~ c Geoche~,;¢try, S;~inger, Heidelberg, 1969, p. 699. $ "1"..~agaya, Y. Sugh---ura and S. T ~ g e , A~z=~-,,o!ec--"-e~, 13 (1950) 3 5 3 .