Cu r v e I — Re a c t i o n Is o t h e r m
pressure of A is o n ly o n e-te n th as larg e as th e p a rtia l pressure of B . In oth er w ords, b y sim p ly c h an g in g th e to ta l pressure on th e syste m and k eep in g all o th er co n d itio n s co n s ta n t, th e ratio of A to -B for th e pressures sho w n h as been d ivid e d b y 100. B y ta k in g th e first d ifferen tial o f th e relatio n sh ip , and e q u a tin g it to o,
B 2 . B 2
in Atm ospheres
T h e ad d itio n of an end p ro d u ct in a n y decomposi
tio n or d issociation process,, su ch as
->■ P C Ij + c i ->• N H i + H C l
2S O2 + o2 - > N i + 311;
ch ecks th e d eco m p o sitio n or d issociation . In other w ord s, less PC I5 w ill d isso ciate in an atm osphere of ch lorin e th a n in an a tm o sp h ere of n itrogen or air.
A m m o n iu m ch lorid e w hen h e a te d in an atm osphere of
r c u ■ ' n h . c i •
2SOa • 2 N H i ■
K A =
K . B = o
A - 3 B , - f £ = K = . l , . - . B = - y i A
d A _ 2B r/B " K ~ 0
one sees th e re is a m axim u m
or m in im u m in th e ra tio of A
0%A,100%B
to B as zero pressu re is
?0-a p p ro ?0-a ch ed . B y ta k in g th e
80-secon d d iffe re n tial 7 0
-d2 A 2
«0-</B2 _ K 50
one finds th e sign to be posi- 40 tiv e , in d ic a tin g th a t th e p a rtia l 30 p ressu re of A as co m p a re d 20
w ith th e p a r tia l p ressu re of 10 B a p p ro a ch es a m inim u m as
100%A,0%B
th e pressu re a p p ro a ch es th e a b so lu te zero ; or co n v e rse ly th e re w o u ld be a m axim u m r e la tiv e y ie ld of B th e closer
one a p p ro a ch ed zero p ressure a b so lu te. T h e ra te of ch an ge can b e st be seen b y d ete rm in in g p o in ts for th e p a ra b o la , B 2 = K A , and p lo ttin g th e re su ltin g c u rv e .1
1 S in c e m o s t o f th e v a lu e s o f K e n c o u n te r e d in th e p r a c t ic a l s t u d y of t h e p r o b le m w e re r e p r e s e n te d b y d e c im a ls , C u r v e s I a n d I I w e re p lo t te d o n th e b a s is o f K =* 0.1.
Total P ressure in Atmospheres
Cu r v e I I — Re a c t i o n Is o t h e r m
a m m o n i a w i l l n o t d i s s o c i a t e t o t h e s a m e e x t e n t as in a v a c u u m o r in a n a t m o s p h e r e c o n t a i n i n g n either a m m o n i a n o r h y d r o c h l o r i c a c i d g a s . L i k e w i s e i t w ould b e e x p e c t e d t h a t e t h y l e n e w o u l d n o t d e c o m p o s e to the s a m e d e g r e e w h e n s u b j e c t e d t o . a h i g h t e m p e r a t u r e m
May, 1914 T H E J O U R N A L O F I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y 389 the presence of h y d ro g e n as w hen s u b je c te d to th e
same te m p e ratu re in an atm o sp h ere of n itrogen . Further, if th e e th y le n e w ere s u b je c te d to th e sam e high te m p eratu re in th e presence of b o th h y d ro g e n and m ethane, th ese tw o co n s titu e n ts in th e c th y le n e - m ethane-hydrogen e q u ilib riu m co u ld be in excess;
as a result, less of th e e th y le n e sh o u ld be d ecom posed in the fo rm atio n o f m eth an e and h y d ro g en . B ro a d ly speaking, to c ra ck p etro leu m in an a tm o sp h ere co n taining all th e h y d ro ca rb o n gases w ith th e ex cep tio n of ethylene, one w ou ld e x p e c t all th e fixed gas com in g from the p e tro leu m to be e th y le n e , a t le a s t u n til th e ethylene co n ten t of th e sy ste m is su fficien t to confo rm to the eq u ilib riu m co n d itio n s. T h e co n sid e ra tio n of these principles seem s to q u estion the n ecessity of usin g valuable gas oil in c o n tin u a lly ge n e ra tin g n ew end products, such as tar- an d h y d ro g e n ; if th e y co u ld be artificially su p p lied th e eq u ilib riu m co n d itio n s w ou ld be satisfied w ith o u t p ro d u cin g new d eco m p o sitio n and polym erization en'd p ro d u cts.
C O M B IN E D I N F L U E N C E O F P R E S S U R E A N D C O N C E N T R A T I O N O N G A S E O U S " R E A C T I O N S
T heoretical co n sid e ratio n of th e effe ct of pressure on gaseous rea ctio n s in d ica te s t h a t an in creased y ie ld of gaseous h y d ro ca rb o n s w ill b e o b ta in e d as th e to t a l pressure on th e s y ste m ap p ro a ch es zero; also an in creased yield of illu m in a n ts w ill b e o b ta in e d b y c ra c k ing the oil in an atm o sp h ere of end p ro d u cts such as hydrogen and m eth an e. On c o m b in atio n th e lo gical conclusion is th a t one sh o u ld o b ta in th e m axim u m yield of illu m in an ts b y c ra ck in g th e p etro leu m a t low pressures and in an a tm o sp h ere of en d p ro d u cts.
Upon first co n sid e ratio n one m ig h t re a so n a b ly qu es
tion the idea of a d d in g h y d ro g e n or m eth an e to a vacuum, b u t th is in v e s tig a tio n deals w ith re la tiv e partial pressures, regardless of w h eth er th e to t a l pressure equals fifty a tm o sp h eres or o n e-fiftieth of one atmosphere abso lu te.
I N F L U E N C E O F C A T A L Y S T S O N G A S E O U S R E A C T I O N S
C ataly tic a gen ts su ch as p la tin u m , p a llad iu m ,
■cobalt and n ickel do n ot, in a n y w a y , in flu en ce final
■conditions of e q u ilib riu m ; th e y m erely h a sten th e ra te
■at which th e s y ste m reach es its final eq u ilib riu m . Whereas eth yle n e an d h y d ro g e n do n o t com bin e to an
•appreciable d egree w h en h e a te d to io o ° C . in th e
•absence of a c a ta ly z e r , th e sam e m ix tu re passed o v er
■colloidal p allad iu m h e a te d to io o ° C . u n ites to fo rm a
•considerable p e rcen ta ge of eth an e. L ik e w ise C O and H2 or C 0 2 and H 2 can be in in tim a te c o n ta c t a t 2000 to 3000 w ith o u t a p p re ciab le re a ctio n in th e fo rm atio n
■of methane, b u t w hen th e sam e p ro p o rtio n s are b ro u g h t together in th e presence o f a c a t a ly tic a g e n t su ch as nickel or co b a lt th e re is a v e ry larg e y ie ld of m eth an e
■and w ater.1 V ig n o n 2 finds th a t lim e h as m uch th e sam e
•effect on the co m b in atio n of C O an d H 2.
TH E V A N ’T H O F F D I F F E R E N T I A L E Q U A T I O N S H O W I N G T H E R E L A T I O N O F K T O k'
To all stu d e n ts of p h y s ic a l ch e m istry th e p ro p o si-.
1 M ay er, H e n s e lin g a n d A lti n a y e r , J o u r . f . G asb., 1 9 0 9 , p p . 166, 1 94;
■ Jockum, 76/d., 1 9 1 4 p p . 73 103, 124, 149; O rlo w , J o u r . R u s s . P h y s . C h em ., ls 08> P - 1588.
* V ignon, L .. C o m p t. r e n d ., 1 9 1 3 , p p . 1 3 1 -1 3 4 .
tio n of B e rth e lo t and T h o m so n t h a t “ e v e r y ch em ical ch an ge g iv e s rise to th e p ro d u ctio n o f th o se su b sta n ces w hich occasion th e g re a te st d e v e lo p m e n t of h e a t ” is fa m ilia r. W ere th is tru e, it w ou ld be e a sy to p re d ict w h ich of tw o g iv e n re a ctio n s w o u ld ta k e p lace a t a g iv e n te m p e ra tu re . C h e m ists to d a y recogn ize th e fa lla c y of th e s ta te m e n t b ecau se in all ch em ical rea ctio n s one deals w ith th e a d d itio n a l so-called
“ la te n t e n e r g y .” B e r th e lo t’s p rin cip le d isregard s th is m o lecu lar en e rg y , and assum es th e free en e rg y , term ed m axim u m w o rk, to be eq u a l to th e to ta l e n e rg y chan ge.
N ern st m a in ta in s th a t th is is tru e o n ly a t th e ab so lu te zero, i. c., th e e n tro p y of liq u id s an d solids a t ab so lu te zero te m p e ra tu re eq u a ls zero.
T h e v a n ’t H off e q u a tio n sh o w in g th e re latio n b e tw e e n K an d K ' is exp ressed b y
/ T d o g <■’ K t ) = or d (log j K P) = ^ U p o n in te g ra tio n th is becom cs
log e K p = + co n stan t
W ere it a sim p le m a tte r to d eterm in e th e va lu e of th is c o n s ta n t o f in te g ra tio n , as w ell as th e v a lu e of q a t th e d ifferen t te m p e ra tu re s (in o th er w ord s in te g ra te th e exp ression to a b so lu te un its) th is w ou ld c o n s ti
tu te a m a th e m a tic a l exp ression for w h a t som e consider a th ird la w of th e rm o d y n a m ics. A s y e t th e re is no su ch a cc e p te d in te g ra tio n , and th e b e st so lu tio n is to use a p p ro x im a te exp ressions, rem em b erin g a t all tim es th a t th e exp ressions are a p p ro x im a te , and m akin g in te llig e n t use o f th e m as such . I t is po ssible to a v o id th e co n s ta n t of in te g ra tio n , h o w e ver, b y in t e g ra tin g b etw e en lim its p ' an d p to
lo g c K P. — lo g e K P = ^
T h is in te g ra te d exp ression is e x tre m e ly im p o rta n t in d ete rm in in g th e v a lu e of K ' fo r a n y desired te m p e ra tu re a fte r th e v a lu e of K fo r a n y o th er te m p e ra tu re h as b een e x p e rim e n ta lly d eterm in ed . I t is also of va lu e in sh o w in g relatio n sh ip s b etw e en K an d K ’ fo r tw o d ifferen t te m p e ratu re s, w here n eith er has b een d eterm in ed , b u t in th is case it expresses re la tio n sh ip s and n o t d ire ct v a lu e s. F o r in stan ce, assum e t h a t one w ish ed to find th e relatio n sh ip b etw e en K a n d K ' fo r th e rea ctio n
2C + H 2 = C2H 2— 58100 cal.
a t th e te m p e ra tu re s 600 ° and 900° C .
lo g e Kp, - log « Kp = ° ° - g J3 ) = 8.49
log e = 8.49 or, logm = 3-69
T i p A p
w hence Keoo = 9°°
4900
T H E N E R N S T A P P R O X I M A T I O N F O R M U L A F O R K E v e n th o u gh co rrect, i f is a v a lu e b ased on th e as
su m p tio n th a t su fficien t tim e elapses to allo w th e s y s te m to reach co m p lete eq u ilib riu m . W hen d ealin g
3 9° T H E J O U R N A L O F I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y V ol. 6, No. 5 w ith h y d ro ca rb o n s a t d ifferen t te m p eratu re s, . th is
m ust n ot be o v erlo o k ed . In fa c t th e tim e elem ent is of such p rim a ry m o m en t th a t n u m erica lly co rrect v a lu e s fo r K w o u ld be of little m ore p ra ctic a l use in gas m a n u fa ctu re th a n a p p ro x im ate va lu es. In th e case of re a c tin g gases one does n o t h a ve th e speed co n d itio n s th a t o rd in a rily ex ist in solutions. On th e o th er h an d , gases b ro u g h t to g e th e r a t su fficien tly h igh te m p e ra tu re s do reach eq u ilib riu m p ra c tic a lly in s ta n tly . I t is im p o rta n t to b rin g o u t th ese lim ita tio n s d esp ite th e v a lu e of a p p ro x im ate q u a n tita tiv e expressions- such as th e N ern st fo rm u la; th e y are of im m en se v a lu e in p re d ictin g th e te n d e n c y of a reactio n . In th is p a p e r th e exp ression is m erely used; its d e riv a tio n w ith co m m en ts can be fou n d in th e sev en th G erm an ed itio n of N e rn s t’s “ T h e o re tica l C h e m is tr y ,”
J e llin e k ’s “ P h y s ik a lis ch e C h em ie der G a sre a k tio n e n ,”
or S a c k u r ’s “ T h erm o ch em ie und T h e r m o d y n a m ik .” 1 log K = — — + 2 d 1.75 log T + 2 vC
4 - 5 7 1 1
w here q is th e h e a t d ev elo p e d a t o rd in a ry te m p e ra tu res and u n der c o n s ta n t pressure, as ta k e n from th e rm o ch e m ica l ta b le s; 2jj rep resents th e vo lu m e ch an ges, an d ^ v C rep resen ts a su m m a tio n o f co n stan ts.
T h ese c o n stan ts are g iv e n as fo llo w s:
I i : 1 .6 C sH s 2 . 6 C2H2 3 . 2 C O 3 . 5 H - 0 3 . 6
C H . 2 . 5 CsH« 2 . 8 C $ H , 3 . 0 C O i 3 . 2 O : 2 . 8
T o use N e rn s t’s w ords, th e eq u a tio n g iv e s a “ fa irly a c c u r a t e ” id ea of th e s ta te of eq u ilib riu m in a syste m .
T h e a p p ro x im atio n is a p p lied in th is fash ion : C + 2H 2 = C H i -f- 18900 cal.
+ 18900 —
lo g Ktoo = 4 S71 - g7~3 — 1 . 7 5 1 o g 8 7 3 — 0 . 7 = — 1 .1 1 - 2 .8 9 ( a )
+ 18900 —
lo g K i m - 4 5 7 i x 1023 ~ 1 ' 75 lo g 1023 ~ 0 7 = — 1 -9 3 - 2 .0 7
+ 18900 —
lo g K900 - 4 5 n x H 7 3 — 1 .7 5 lo g 1173 — 0 .7 = — 2 .5 5 - 3 .4 5 w h e n c e ,
Kcoo = 0 .0 7 7 K iso = 0 .0 1 2 K900 = 0 .003
( a ) N e g a t i v e l o g a r i t h m s m u s t b e c o n v e r t e d i n t o l o g a r i t h m s w i t h p o s i t i v e m a n t i s s a .
In sim ilar m ann er, th e v a lu e s of K , K ' , and K " for E q u a tio n s i , 2, 3, 4, 5, 6, 7, 13, 16, 17, 18, and 22 in T a b le II h a v e been calcu late d . In those rea ctio n s in v o lv in g C O and CO», as 19, 23, and 26, use h as been m ade of th e ap p ro x im atio n form u las for th e sam e as w o rke d o u t b y M a y e r and co -w o rke rs,1 b u t s u b s titu tin g th e v a lu e s ,of q show n in th e ta b le .
C A L C U L A T I O N O F H E A T S O F R E A C T I O N S F O R D I F F E R E N T E Q U I L I B R I A
T h e h ea t abso rb ed or e m itte d in a g iv en rea ctio n w as d ete rm in ed b y m eans of th e o rd in a ry th e rm o ch e m ica l m eth od s of a d d itio n and su b tra c tio n , as in th e fo llo w in g ty p ic a l ex a m p les:
(a) 2 C + 8 1-I - 2 C H t + 3 7 8 0 0 c a l.
2 C + 4 H - C;H < — 14600 c a l.
2C H < = C3H4 + 2 H ; — 5 2 4 0 0 cal.
(¡0 6 C + 6 H = 3 C !Hi— 174300 cal.
6 C + 6 I I - C s H t — 11300 c a l.
3C = H : - C ell« + 163000 cal.
1 M a y e r , H e n s e l i n g a n d A l t m a y e r , J o u r . G asb., 1 9 09, p p . 166, 194, 238.
(c) C + 2 H2 - CH < + 18900 cal.
2 H + 0 = IlaO 4 - 5 8 3 0 0 cal.
CH < + H2O » 3 H i 4- C 4- O — 7 7 2 0 0 cal.
C 4- O = C O + 2 9 0 0 0 cal.
CH< 4- H jO = 3 H i 4- C O — 4 8 2 0 0 cal.
I t is like w ise p o ssible to com bin e th e v a lu e s of K for one rea ctio n w ith K ' for a second reactio n in order to d eterm in e K " for th e re su lta n t reactio n .
C + 2H0 = C H 4 K = ¿ p P 'm .a C + H 2 = C 2H 2 K ' =
P l\3
D iv id in g th e sq u are of th e m eth an e equilibrium by th e a ce ty le n e eq u ilib riu m , one ge ts
rrn _ ( K ) _ Pctm PjU l _ PClHi P3lll
( A ) “ P iu P 'c iw P2 c m
T h is o p eratio n can be rep resen ted b y th e equation 2CH4 = c 2h 2 + 3 h 2
In th is w o rk th e v a lu e s of K an d K ' h a v e been com
b in ed in th e m ann er ju s t show n in order to determine v a lu e s for e q u a tio n s 8, 9, 10, 1 1 , 12, and 14. The N e rn st a p p ro x im atio n fo rm u la co u ld be applied di
re c tly to each of th e se e q u a tio n s w ith th e sam e results.
A ll re a ctio n s in d ic a te d in T a b le II m a y go in either d irectio n . A tte n tio n is again called to th e fa ct that th e rea ctio n s g iv en m u st be used w ith a consideration of all fa cto rs in v o lv e d ; no e q u a tio n b y itse lf repre
sen ts a co m p lete sy ste m . A ll th e gases mentioned,, to g e th e r w ith m a n y oth ers, are te n d in g to reach eq u ilib riu m w ith one a n o th er. T a r com pounds were n o t listed . B en zen e, C 6H 6, h as been used as typical of all ta r fo rm atio n s. In te ch n ica l p ra ctic e one gets benzene and o th er ta r co m p o u n d s from methane h y d ro ca rb o n s; from ex p erim e n ta l evid ence, it is- k n o w n t h a t fro m e th y le n e 1 or a c e ty le n e 2 th e same re
su lts are reach ed . T h ro u g h o u t th e literatu re one finds q u estion s as to w h eth er m eth an e goes to acetylene, or a ce ty le n e to m eth an e, eth an e to e th yle n e , ethylene to eth an e, etc. C on sidered in th e lig h t of this study it ap p ears th a t regardless of w h ich hydrocarbon is- used in itia lly th e re is a pron ou n ced te n d en cy for the sy ste m to reach a com m on e q u ilib riu m dependent upon th e e x istin g te m p e ra tu re . W ith h yd ro carb on s the resu lt seem s to dep end m ore upon co n d itio n s of temper
a tu re , pressure and co n ce n tratio n th a n upon th e initial h y d ro ca rb o n s. In o th er w ords, w ith proper condi
tio n s of te m p e ra tu re , pressure an d concen tratio n, and w ith su fficien t tim e for co m p lete reactio n , the final eq u ilib riu m w’ill be th a t of th e m en tio n ed hydrocarbons and th e ir re a ctio n p ro d u cts, regardless of whether d ecane, h exane, eth an e, m eth an e, e th yle n e or acetylene,5 sin g ly or in m ixtu re s, are used in th e beginning.
T a b le II fu rn ish es th e basis fo r th e e x p e r im e n ta l w o rk o f th is research . Its in te rp re ta tio n serves as- a gu id e in d ete rm in in g th e d irectio n of e x p e rim e n ts .
1 I p a t ie w , B e r., 1 9 11, p . 2 9 7 8 ; I p a t ie w a n d R o n ta la , Ib id .. 1913, p. 1748.
= R . M e y e r , I b id .. 1 9 12, p , 1609; M e y e r a n d T a n z e n , I b id ., 1913, p . 3183.
3 W . A . B o n e , J o u r . f . G asb., 19C8, p . 8 0 3 ; D . T . D a y , A m . Ckem- J o u r ., 1 886, p, 1 53; V . L e w es, Proc. R o y . S o c., 18 94, p . 9 0 ; Worstall a n d B u r w e ll, A m . C hcm . J o u r ., 1 8 9 7 , p . 8 1 5 ; B o n e a n d C o w a rd , Jour.
C h em . S o c., 1 9 08, p . 1197; S a b a t ie r a n d S e n d c r e n s , C o m p t. rend., 130,.
15 5 9 ; C . P a a l , C h cm . Z tg ., 1 9 12, p . 6 0 ; I p a t ie w , B e r., 44, 2987.
May, 1914 T E E J O U R N A L O F I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y 391
Taking E q u a tio n 9 as ty p ic a l, w h ere -fiT6oo = 0.0000001 K»°» K «o k mo
and Kooo = 0.0004, - it seem s a d v isa b le to exceed 16 c + HiO ^— c o + Hi 0.2 3.1 25.0 900° C. in te m p e ra tu re . H o w eve r, referrin g to 19 CH* + H«0 ^ — CO +3H 1.. 0.06 8.7 346.0 Keoo - 0.077 and X 90o = 0.003 fo r E q u a tio n 3, it is and t h a t a te m p e ra tu re of 9000 C . is fa v o r a b le to th e C O evident th a t th e r a te a t w h ich m eth an e w o u ld de- an d H 2 fo rm atio n of 16, b u t u n fa v o ra b le to th e m eth an e compose to carb o n an d h y d ro g e n , in a cco rd an ce w ith p re se rv a tio n in E q u a tio n 19. On th e oth er h and, Equation 3, m ig h t e a sily be su fficien t to offset all * a te m p e ra tu re of 6000 C . is u n fa v o ra b le to p rese rva- C2H4 form ation , in a cco rd an ce w ith E q u a tio n 9. tio n of C O and H 2in E q u a tio n 16 b u t is m ore fa v o ra b le
Considering E q u a tio n s 16 and 19, tw o of th e m ost th a n 900° to h y d ro ca rb o n fo rm atio n or p rese rv atio n , vital in present ca rb u re te d w a te r gas m a n u fa ctu re , one A lso it is m ore fa v o ra b le to fo rm atio n o f C 0 2 as show n
finds • b y E q u a tio n 17. T h ese te m p e ra tu re effe cts can be
Ta b u s I I — Qu a n t i t a t i v e St u d y o f Eq u i l i b r i a
Ap p r o x i m a t e
He a t so p Vo l u m e ( F o r m u la s r e f e r to
N o. Re a c t io n s Re a c t io n.
+ 9 7 6 5 0
— 3 9 6 5 0
Ch a n g e s 1 to 1
1 to 2
p a r t i a l p re s s u re s ) A = 5 ° !
Keoo 6 9 X 1024
K750 Kfloo
2. C O , + r -7^ 2 C O ...
02 K - (C O )!
C O i 0 .1 3 . 9 5 9 . 0
3. C + 2 H , C H . ... + 18900 2 to 1 ,
g|lII
* 0 .0 7 7 0 .0 1 2 0 .0 0 3
4. 2 C + 3 H i C -H « ... + 2 3 3 0 0 3 to 1 * II ¿4' '¿L
2 . 2 X 10-» 1 .7 X 10-8 2 . 5 X 10 »
5. 2 C + 2 H j C3H1... — 14600 2 to 1
( H i) 1 6 . 0 X 10“ 10 1 .6 X 10-» 3 . 2 X 10-8
6. 2 C + H i C i H i ... — 5 8 1 0 0 1 to 1 K = Ci-H =
H i 1 .1 X I 0 “ 1J 1 .5 X IO "” 5 . 7 X IO-10
7. 6 C + -ITT, C . H . ... — 11300 3 to 1 C tH s
( H i) 8 1 .2 X 10-»» 1 .7 X 1 0 - “ 2 . 2 X IO“ “
8. CiH » C iH . + h, ... — 3 7 9 0 0 1 to 2 C iH , X H i
K — — ...
C iH e
0 .0 0 2 7 0 .0 9 4 1 .2 8
9. • 2 C H , v C .H . + 7.11?... — 5 2 4 0 0 2 to 3 C iH , X ( H i) 1 A =
---( C H t)>
0 .0 0 0 0 0 0 1 0 .0 0 0 0 1 0 .0 0 0 4
10. 2 C H , C1H1 + 3 H ; ... — 9 5 9 0 0 2 to 4 C1H1 X (H a )3
( C H , ) 1 1 .8 6 X IO -» 0 .0 0 0 0 0 0 1 0 .0 0 0 0 6
11. C iH , -v C iH i + H i ... — 43500 1 t o 2 C1H1 X H i
A =*
C iH , 0 .0 0 0 1 8 0 .0 0 9 3 0 .1 7 8
12. C iH 6 . C iH i + ? H a ... — 81400 1 to 3 C iH i X ( H i) 1
K = • ...
C iH , 0 .0 0 0 0 0 0 5 0 .0 0 0 8 9 0 .2 2 8
13. C ,H j 2 C i H , ... — 3 1 8 0 0 1 to 2 „ (C1H, ) 1 A =
---C ,H a 1 .4 1 3 1 .6 2 5 8 .0
14. 3 C iH i C «H 6... + 163000 3 to 1 C .H ,
( C iH i) 3 9 X 1 0 « 5 X 101» 1 .2 X 101*
15. 3 C iH , C sH s + 3 H i ... + 3 2 5 0 0 3 to 4 C cH , X ( H i ) 3
( C iH ,) 3 5 . 5 X 1 0 « 4 . 1 X lO ii 6 . 7 X 10i°
16. C + H iO C O + H i ... — 2 9 3 0 0 1 to 2 C O X H i
A. — •
H jO 0 . 2 3 .1 25
17. C + 2 H iO ____ C O : + 2 H s ... — 19000 2 to 3 w C O2 X ( H j) 1 K — ... ..
-(H sO )2 0 . 4 2 .5 11
18. H iO + C O ____ C O i + H i ... + 10350 2 to 2 K _ C O2 X Ha H2O X C O
1 .9 5 0 .8 1 0 .4 2
19. C H , + H iO " 7 ^ C O + 3 H i ... — 4 8 2 0 0 2 to 4 C O X ( H 2)*
C H 4 X H iO
0 . 0 6 8 .7 3 4 6 .0
20. C jH , + 2 H iO 2 C O + 4 H i. . ., — 44000 3 to 6 (C O ) j X ( H2)4
C2H4 X ( H 20 ) =
21. ____ r ( C O ) 2 X ( H2)3
C iH : - f 2H aO ^ --- 2 C O + 3 H i. . . — 5 00 3 to 5
C2H2x (H2O) 2
22. CsHg + 6H1O 6C O + 9 H i. . ,. — 164500 7 to 15 (C O )« X ( H2)9
C elle X ( H2O)« 1 .2 X IO” 7 0 .4 9 4 8 0 0 0
23. , — 3 7 9 0 0 3 to 5 C O2 X (H s)4
0 . 3 16 28 0
C H < X ( H20 ) 2
24. C iH , + 4 H iO 2 C O i + 6H1.. . + 23400 5 to 8 (C O2)2 X ( H2)6
C2H4 X ( H2O) 4
25. C1H1 + 4 H , 0 ' 2 C O i + 5 H i.. , + 20100 (C O2)2 X (H t)s
C2H2 X ( H2O)*
26. C H , + C O , 2 C O + 2 H i . . . — 5 8 5 0 0 2 to 4 r ( C O) 2 X (H i)*
CH < x C O i 0 .0 1 7 5 3 54
27. C iH , + 2 C O i 4 C O + 2 H i . . . . — 6 4 6 0 0 3 to 6 K (C O) 4 X (H i)*
C2H4 X ( C 02) 2
28. C1H1 + 2 C O : ^ ± l 4 C O + H i — 3 1 1 0 0 3 to 5 (C O )« X H i
C2H2X (C O2)2
T H E J O U R N A L O F I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y Vol. 6, No. 5 m ore cle a rly u n dersto o d b y referen ce to t h e . first
n u m erical p ro b lem cited , an d to th e th e o re tic a l m ix
tu re s g iv en for E q u a tio n 19 a t te m p e ratu re s of 6oo°
and 900° C . I t ap p ears im p ossible to find a te m p e ra tu re fa v o ra b le to b o th w hen th e tw o reactio n s are sim u lta n e o u sly carried o u t. In order to p reserve th e h y d ro ca rb o n s it b ecom es n ecessary to fo rm H 20 , CO2 an d d ep o sit carb o n ; or in order to a vo id fo rm in g . w a te r v a p o r, C 0 2 and d ep osit carb o n , it becom es n ecessa ry to d e stro y h y d ro ca rb o n s. T h e tw o can n o t be reconciled.
S U M M A R Y
O n th e o re tic a l grou n d s, th e re fo re , it ap p ears:
I— P o ssib le to so cre ate co n d itio n s th a t th e oil c ra ck in g p rocess can be carried o u t a t a h igh er te m p e ra tu re th a n is n ow used in oil gas processes, and th e re b y g r e a tly in crease th e y ie ld of v a lu a b le h yd ro ca rb o n s.
I I — P ossib le to “ c ra c k ” oil w ith o u t d ep o sitin g carbon, and w ith o u t th e fo rm atio n of w a ter v a p o r an d C 0 2.
I I I — P o ssib le to p a r tia lly co n tro l th e q u a n tity and co m p o sitio n of “ t a r ” p rod u ced in gas m an u factu re .
I V — Im p o ssib le to p rese rv e h y d ro ca rb o n s and a t th e sam e tim e a v o id C 0 2, w a te r v a p o r, and d ep osited carbo n , w hen oil is “ c r a c k e d ” as in th e present c a r
b u re te d w a te r gas process.
In te rp re ta tio n o f T a b le I I an d th e resu lts w hich co u ld be e x p e cte d in gas reactio n s, in v o lv in g th e co n s titu e n ts sh o w n , co u ld be e xp an d ed in d e fin ite ly.
T h a t th e se th e o re tic a l co n sid eratio n s are of m ore th a n aca d em ic in te re st w ill be b ro u g h t o u t in su b seq u en t p apers.
Ch e m i c a l En g i n e e r i n g La b o r a t o r y Co l u m b i a Un i v e r s i t y
Ne w Yo r k
A M E T H O D F O R T H E D E T E R M I N A T IO N O F M A G N E S IU M IN C A L C IU M S A L T S 1
B y J . C . I I O S T E T T E R
In th e course o f th e p rep ara tio n o f som e calciu m silica te s for th e rm a l s tu d y , certain sam ples of calciu m carb o n a te w ere te ste d to d ete rm in e th e ir s u ita b ility as sources o f lim e. A n a ly se s o f th ese sam p les show ed th a t, of th e n o n -v o latile im p u rities d eterm in ed b y th e m akers, th e a m o u n ts rep o rte d b y th e m w ere su b sta n tia lly co rre ct fo r all e le m e n ts2 ex ce p t m agnesium . T h is e lem e n t w as fo u n d to be p rese n t to th e e x te n t of s e v eral te n th s o f a per cen t as oxid e, even th o u gh the sa lts a n a ly z e d w ere of th e v e r y h igh est grad es o b ta in a b le, an d th e m a k e rs’ a n a ly se s h ad sho w n b u t a
“ tr a c e ,” or, a t m ost, 0.005 per cen t M g O . A d is
c re p a n c y of th is large ord er co u ld h a rd ly be passed o v er w ith o u t in v e stig a tio n , ev en th o u gh th e problem th u s p resen ted w as b u t a m ere side issue. T h e w rite r’s resu lts on th ese sam p les h ad b een o b ta in e d b y th e calciu m s u lfa te se p a ra tio n , b u t, sin ce th e la b o ra to ry m an ip u latio n of th is m eth od w as to o in v o lv e d for
c re p a n c y of th is large ord er co u ld h a rd ly be passed o v er w ith o u t in v e stig a tio n , ev en th o u gh th e problem th u s p resen ted w as b u t a m ere side issue. T h e w rite r’s resu lts on th ese sam p les h ad b een o b ta in e d b y th e calciu m s u lfa te se p a ra tio n , b u t, sin ce th e la b o ra to ry m an ip u latio n of th is m eth od w as to o in v o lv e d for