CHEMICAL
Ł M E T A L L U R f l I C A l
ENGINEERING
ESTABLISHED 1902 S. D. KIRKPATRICK, EcJifor
MARCH, 1942
U N C O V ER THE U N O R T H O D O X
C o l o n e l M a u r i c e
E.
B a r k e rof tlie Chemical W arfare Service made headlines all over the United States the other day when he said that what this country needs most now is a non-eomic-strip ray gun. The wide reaction to his chance remark, be
fore a student group at the College of William and Mary, may reflect only the shallow and wishful thinking of those who would like to see this war won by some of Buck Rogers’ 25th century tech
nology. Yet there may be food for more sober thought in the idea that the scientists and engi
neers of this country have got to do more to help the war program. We are pitted against ruthless enemies that are staking their every resource in a desperate effort to conquer the world. So fa r they have .been getting away with it. And they will con
tinue until we have mustered the scientific brains as well as the manpower and materiel to beat them at their own fiendish game.
Lately some of us had the rare privilege of hear
ing C anada’s commanding officer, Lieutenant Gen
eral A. G. L. McNaugliton, address his fellow engi
neers on the occasion of his recent retu rn from the other side. He said bluntly and forcefully that this war was not going to be won by orthodox methods or by mere manpower sent as expeditionary forces to do guard duty in various outposts of the'B ritish Empire. His plea was for the scientists and engi
neers of Canada to develop new and more deadly weapons. He was looking for help, not from the politicians or from the brass hats of the army of yesterday, but from his former colleagues and as
sociates in the National Research Council and in the laboratories of Canadian universities and in
dustries. Judging from the fervor with which the General’s plea was received, our guess is that great things will be forthcoming—developments as im
portant now as once were the Banting discoveries of insulin in more peaceful time.
No one can deny that we have made progress here in mobilizing our research and developmental resources for war work. The various agencies and committees included under the broad program of the National Academy of Science have drafted some of our best scientists and most resourceful engineers. Yet many of us have the impression that there is still a discouraging gap between the lab or tories and drafting boards of some of our war in
dustries, between research and production of new and .better processes, as well as weapons. We still rely too much on the strategy of the past.
Our present need is for output of absolutely necessary equipment—of planes and ships, guns and ammunition. Orthodox methods, standardized designs and other mass production techniques will get quickest results and, of course, there is no time to lose. Nevertheless, we must not be afraid of change and must seek constant improvement—even radical and revolutionary developments in every line of mamifacture. Otherwise we are going to be handicapped in fighting better equipped as well as better prepared enemies.
W ith this in mind we want to urge our govern
ment to give more serious and sympathetic consid
eration to the vital role of research in the war ef
fort. Our Selective Service Director must help to make it clear to the local boards th at the man in the laboratory who is working on a new aviation fuel, a more powerful explosive, or a new alloy or plastic is just as im portant as the man in the plant. And th at both, in their present jobs, might conceivably be more im portant than a whole regiment handi
capped with obsolete equipment.
Given opportunity and support, American engi-
neers and research men can help ■win this war in ways th at
110one can now foresee or predict. They have w hat it takes 'in scientific knowledge and re
sources. They are already on the job, but they need a little encouragement—especially from those in high quarters who can and will p u t to test their ideas—however unorthodox.
THEIR BROTHERS' KEEPERS
A l p h a C h i S ig m a ,
the professional chemical fra ternity with 15,000 members, 46 collegiate chapters, and 25 alumni groups in our principal chemical centers, has again contributed a signal service to the advancement of chemistry and chemical engi
neering. By setting up a comprehensive safety program in cooperation with the National Safety Council, it is going to help get the principles and objectives of the safety movement established in the classrooms and the laboratories of American colleges and universities. Tims will be brought home to the student early in his academic career the vital relation between theory and practice when it comes to accident prevention and the sav
ing of life and property.
Credit for organizing this program goes to H. B.
Stevenson of Procter & Gamble, who, as a district counselor of the fraternity, helped to form ulate systematic instruction in safety at the University of Cincinnati and at Case School of Applied Science.
Now, under the chairmanship of F. R. Holden of Mellon Institute, an active committee is spreading out the program to reach all collegiate chapters.
Meanwhile the national organization of Alpha Chi Sigma is helping to finance memberships in the National Safety Council and is otherwise backing up the work of its committee.
In the past our educational institutions have often been severely indicted because graduate chemists and chemical engineers have been p er
mitted to enter industry without intimate knowl
edge and understanding of the hazards th a t are involved in the use of high tem peratures and pressures and in the handling of toxic and flammable materials. Such indictments have been all too frequent. Let us hope th at the new genera
tions of graduates will become so conscious of safety during their college days th at they can inculcate among - their associates a better under
standing of the human principles
011which modern industry must operate.
ANY IDLE EQUIPMENT?
To
a i din diverting idle and non-essential chemical engineering equipment to direct w ar purposes, there has been set up in the Chemical Branch of W.P.B. a new section on Chemical P la n t Facili
ties. Its chief is C. T. Thompson whose office is in Room 2434, Temporary Building R, in W ashing
ton, D. C. He will serve as a liaison officer between people who may be able to produce some
essential product and people who may have equip
ment not engaged in direct war production or have idle facilities. I t should be noted, however, that this section is concerned only with equipment already installed and not with new equipment.
Also those having such equipment should not only list and describe it and its past usage, b u t should, if possible, suggest applications for which it m ight be adapted. Finally, there is the question of whether the equipment can be used in its present place or would be available for relocation. Here, then, are job specifications for an opportunity to serve your country. Mr. Thompson invites your contacts.
IS YOUR SHOP FULL?
E v e r y
plant in the chemical process industries has a good machine shop for its repair and m ain
tenance work. In some cases these shops may be working on an 8-hour basis only 5 days a week.
The other 75 percent of the week should not find them standing idle in emergency times such as these when every m inute counts.
Have you made any plans to keep all of the machines in your shop busy on a 168-hour week, turning out a needed item of war m aterial when not actually needed for repair? There is no reason why a subcontracting arrangem ent cannot be made with a nearby producer of a war item. I f the shop is really large, a prime contract may be justified.
Provision must, of course, be made for actual repair and maintenance needed in the plant. B ut intensive up-grading of present machine shop employees will quickly develop an adequate, skilled staff which can keep the machines running con
tinuously making th at extra effort which war necessitates.
Subcontracting exhibits of the contract distribu
tion branch, W ar Production Board, are now open at the addresses listed below. Visit the nearest office and see what you can do to help.
City Location
A tla n ta, Ga. H u rt B uilding
Boston, Mass. C ourt S tre et B ranch, First, N ational B ank
Buffalo, N. Y. W hite Building
Chicago, 111. Civic O pera B uilding C incinnati, Ohio U nion C entral L ife
B uilding
Cleveland, Ohio U nion Commerce B uilding D etroit, M ich. B oulevard B uilding H arrisb u rg , P a. Doeline B uilding H elena, Mont. 222 P ow er Block K ansas City, Mo. M utual S ta te B uilding Los Angeles, Calif. W estern Pacific B uilding M emphis, Tenn. S terick B uilding
Newark, N. J . Indem nity B uilding
New Orleans, La. Canal B uilding New Y ork, N. Y. C hanin B uilding
Philadelphia, P a. B road St. S tation Building S an Francisco, Calif. W hitcom b H otel
St. Louis, Mo. B oatm en’s B an k B uilding
70— 3 • M A R C H 19!,2 • CHEM ICAL & M ETALLUR GICAL E N G IN E E R IN G
W A S H I N G T O N H I G H L I G H T S
CON VERSION of industrial plants
must be p ro m p t and thorough. This means th a t m etal-w orking establish
m ents in p a rtic u la r m ust do some
thing o f direct value on the w ar job, or else. . . . Otherwise, they will certainly be w ithout raw m aterials because the. shortage of m etals is tru ly appalling. F o r chemical plants it means th a t the things made m ust be u rgently wanted fo r w ar usage or fo r an absolutely essential civilian activity. H ere com forts or luxuries will no longer qualify.
ERNEST W . REID has been named
chief o f the Chemical and Allied P roducts B ranch o f W .P.B. Thus an outstanding public service rendered by an exceptionally able technical man is signally recognized. E. E . W eidlein, who cannot give fu ll tim e to W ashington activities, continues as an enthusiastic and invaluable con
sultant, giving p a rtic u la r attention to synthetic rubber. Prom otion of Dr. Reid seems to have received u n an imous su p p o rt both w ithin and w ith
out the governm ent. I n view o f the quiet, though very com petent job he has done, this is n o t surprising.
PUBLIC O PIN IO N still has influence.
D uring F e b ru ary it forced reorgan
ization o f the Office o f Civilian De
fense and turned th a t agency back to its original technical job. T hat was a good thing. I t also compelled Con
gress to re tre a t from the proposed retirem ent annuities fo r members of Congress, the C abinet and the P resi
dent. T h at m ay o r m ay not have been so good. I t is easy to under
stand why the general public objected to pensions fo r politicians. B ut the public probably does not realize th a t the nam ing o f lame-duck congressmen to governm ent jobs, lest they be in straiten ed circum stances, already costs us m ore than the whole p ro posed pension system.
TANKER sinkings in dangerous
num bers make certain a shortage of petroleum products in m any sections o f the U nited States. Mr. Tekes’
w orst forecasts o f last F all Trill, ho exceeded, but not fo r the reasons then given. This m eans th a t some process industries m ust substitute coal fo r oil w herever possible. Hence the storage of coal this S p rin g and Summer is being urged. This is one thin g which should be hoarded by industry. Some
firms which require oil m ay have to establish new processing u nits n ea r the source of petroleum . H ighly de
sirable p rojects fo r the N ortheastern S tates may not be p ractical there.
M aking o f butadiene, fo r example, would have to move largely to Texas and the Southwest.
ALCOHOL m aking is still the subject o f b itter controversy in W ashington.
The huge new requirem ents fo r syn
thetic rubber and smokeless pow der caused m ost of the trouble. B ut much more commotion resulted from inac
curate, biased and even erroneous statem ents th a t seemed deliberately distorted. There is no question but th a t the governm ent will give alcohol m akers the very minimum quantity of sugar or edible alcohol which is needed fo r the minimum safe total alcohol production o f the country.
P reference will be given to every other raw m aterial first. B ut the n arrow m argin o f corn supply above dem and is m aking it necessary even to substitute w heat as a raw m aterial in some cases. Meanwhile, the
“pow er alcohol” and “chem urgic”
politicians from the Middlewest are having a field day w ith th eir rum ors o f a sinister control of alcohol, and rubber by international chemical and petroleum interests.
EXPA NSION of industrial produc
tion is 'u rg e n tly wanted with respect to almost every chemical. B u t this expansion m ust be accomplished with presen t m anufacturing facilities if th a t is hum anly possible. Even lower efficiency and m akeshift chemical en
gineering methods are p referre d to the spending of tim e or scarce equip
m ent on p la n t additions.
DELAYS in synthetic rubber produc
tion have already occasioned severe Congressional criticism, and form al inquiry. A lot of folks would like to find out whether the R.F.C. Czar deserves his cocktail p a rty nickname of “Bottleneck” Jones.
BETTER LOAD FACTORS fo r electro
chemical industry are being urged by the engineers o f the F ederal Power Commission. They ask th a t peak de
m ands be curtailed, especially a t peak-load hours on local u tility sys
tems. The curtailm ent of o u tp u t o f a continuous process industry, i f it slows down only two hours each
afternoon five days a week, is n o t serious. Such slowdown often makes available to the o p eratin g com pany pow er which otherwise would not be allocated to it. Then, if priorities fo r equipm ent can be had, one finds the anom aly of low er pow er bills, g rea ter production and lower peak loads 011 the power line. All o f these desirable objectives should be investi
gated by every electrochemical m an
agement.
ALUMINUM and possibly m agne
sium, production from 0-mill pow er is alm ost certain to come. Location o f such p la n ts in the suburbs of the large m etropolitan centers will help to tak e u p the slack in the few areas w here a su rp lu s o f firm pow er is still available. All adm it th a t these are “white elephant” p lan ts, erected only to m eet the presen t emergency.
EXPLOSIVES m aking m ay be slightly curtailed in order to divert some nitrogen products to the fertilize r business. This queer w ar-tim e situ a
tion develops from a com bination of huge new food dem and fo r our Lease- Lend friends a t the same tim e th a t im port o f Chilean n itra te becomes extrem ely difficult because of ship shortage. W e do not dare to tell the B ritish, Russians, o r Chinese th a t we will n o t help to feed them. B ut to feed them, we m ust have more Chilean n itra te or am monium sul
p h ate fo r top and side dressing of both sugar and oil-seed crops. The need fo r more fertilizer nitrogen next y ea r will be much more than an aca
demic facto r in m ilitary planning.
DONALD NELSON says th a t this
(1942) is the crucial year, n o t 1943.
“W e had ou r golden o p p o rtu n ity to expand capacities in steel, chemicals an d other m aterials and neglected it.
T h at o p p o rtu n ity is gone forever, so f a r as this w ar is concerned. This y e a r we have ten silver m onths ahead. W h a t we produce f o r ou r
selves and our Allies now is w orth ten times w hat we produce next J a n u a r y !” M anagem ent holds the key. Think w hat it would m ean if every chemical com pany in the coun
try could im prove the efficiency o f its m anagem ent to reach th a t o f the best ru n enterprises. I t is sa fe to say th a t o u tp u t o f w ar production would go up ‘25 percent w ithout any added equipm ent o r new facilities.
CHEM ICAL & M ETALLURGICAL E N G IN E E R IN G • M A R C H J 2 S— 77
Synthetic Rubber in Industry
H . H . H A R K I N S , U n ited S ta te s R u b b e r Co., P ro v id e n c e , H. i.
— Chem. & Met. I N T E R P R E T A T I O N ...
The rising synthetic rubber production and the rapidly dim inishing supply of the natural m aterial giv e rise to the consideration of how the n ew typ es of rubbers can be u sed for construction of eguipm ent in the process industries. Dr. Harkins d iscusses the peculiar char
acteristics of each of the synthetic rubbers that are now b eing pro
duced com m ercially with sp ecial em phasis on their resistance to heat, oxidation, oil, and ch em icals—
E ditors.D
u k in g the p a s t two o r three y ears there has been much public discussion o f synthetic rubber. M any applications have been found, but the volume o f synthetic ru b b er used thus f a r com pared w ith the volume of n a tu ra l ru b b er consumed is slight.
The to ta l production o f all synthetic rubber in 1941 was only about 1-J p e r
cent o f the crude n a tu ra l rubber con
sum ption. W hile this m ay n o t seem an im pressive figure fo r synthetic rubber, the production has laid the basis fo r possible fu rth e r expansion which is o f g re a t significance in tim e of emergency. Much fu rth e r expan
sion o f the synthetic ru b b er in d u stry is contem plated. M r. Je sse Jones recently announced th a t the Recon
struction F inance C orporation will a p p ro p ria te $400,000,000 f o r the con
struction o f additional synthetic ru b ber p la n ts to bring the annual p ro duction o f synthetic rubber up to 400,000 tons p e r year.
One o f the p rin cip al reasons why the use o f synthetic ru b b er has lagged so f a r behind n a tu ra l ru b b er is due to its being produced in th e F a r E ast w ith cheap labor a t a p rice so low th a t synthetic ru b b er cannot compete.
Ilence, th e only uses fo r synthetic ru b b er thus f a r have been fo r p u r
poses fo r which it is superior in p e r
form ance to the n a tu ra l product.
W ith the sources o f n a tu ra l rubber im periled, o r cut off entirely, synthetic rubber becomes a subject o f v ita l in terest to all of us.
R ubber m an u factu rers are keenly aw are o f th e ir responsibilities to in dustries using this m aterial. U nder
B u n a S c a n b e b o n d e d to m e ta l sa tis fa c to rily a n d h e n c e m a y p r o v e u se fu l a s a lin in g m a te r ia l to r e p la c e r u b b e r in th e p a p e r a n d o th e r p r o c e ss in d u strie s
instructions from the governm ent and also on th eir own initiativ e rubber m an u factu rers are endeavoring to (1) conserve n a tu ra l ru b b er w herever p os
sible, (2) see th a t ru b b e r is allocated to the essential needs of industry, (3) use su bstitute m aterials w here w ar
ra n te d ; fo r example, reclaim ed ru b ber, (4) study intensively the process
ing and the p ro p ertie s o f synthetic rubbers w ith the idea of using them w herever possible when they are available in sufficient quantity.
On the assum ption then th a t in the im m ediate fu tu re we will have little n a tu ra l rubber, b u t a m oderately good su p p ly o f synthetic rubber, to w hat extent can our basic needs be satis
fied? This question is too big fo r an y one to answer definitely a t the present time. H owever, we m ay con
sider the fundam ental p ro p ertie s of the synthetic rubbers and thereby gain some insight into the possibilities of using them fo r various applications in industry.
Before discussing “synthetic ru b ber,’' it is advisable to define this term . M any attem p ts have been m ade to build u p high m olecular weight hydro
carbons to yield a pro d u ct like n a tu ra l rubber. N one o f these efforts has been successful. T herefore, syn
thetic ru b b er does not m ean a product identical w ith n a tu ra l rubber. I t has been possible to build u p o r polym e
rize various substances or m ixture o f substances which can be m ade to yield m aterials o f high stren g th and elas
tic ity resem bling n a tu ra l ru b b er in physical pro p erties. T here are m any synthetic products which exhibit these p ro p ertie s in some degree. I t is in this ra th e r loose sense then th a t the term synthetic ru b b e r will be used.
The m ore im p o rta n t synthetic ru b bers, th e ir chemical and mechanical p roperties, will be discussed and some o f th e ir possible uses will be men
tioned.
F o r detailed inform ation on any
• p a rtic u la r synthetic ru b b er the m anu
fa c tu re r should be consulted. The statem ents which will be m ade are based to a large extent on inform ation received from the m an u factu rers
B a s e d o n a p a p e r p r e s e n t e d b e f o r e t h e r e c e n t a n n u a l m e e t i n g in N e w Y o r k , N . Y., o f t h e T e c h n i c a l A s s o c i a t i o n o f t h e P u l p
& P a p e r I n d u s t r y .
coupled w ith the author’s own obser
vations. They do not necessarily re p resent the views of the com pany w ith which he is connected or of the m anu
fa c tu re r o f the synthetic rubber. In com paring these synthetic rubbers, every effort has been made to be fair.
This com parison is made difficult by the fa c t th a t the pro p erties of any one are largely dependent upon the processing, com pounding, and curing it has received.
I t m ust be m ade clear a t the outset th a t no one synthetic rubber is sa tis
fac to ry fo r all purposes fo r which a rubber-like m aterial is required. B ut by taking advantage o f all o f the various synthetics it m ay be possible, by m aking use of the best p ro p e rty of each, to sa tisfy m ost needs.
According to one authority 29 varieties o f synthetic rubbers were studied in 1941, and th a t one m anu
fa c tu re r has m ade over 200 synthetic rubbers. I t would be impossible to discuss all o f these, even if complete inform ation were available, which it is not,— therefore consideration will be confined to the few types th a t are now commercially available. I t is necessary to p o in t out th a t in the discussion to follow there are num er
ous products u n d er each heading, and therefore no generalizations are valid.
The rubber technologists have been busy form u latin g com pounds which would accom plish certain things which were not supposed to be possible f o r rubber. E xactly the same pos
sibilities exist fo r com pounding each o f the synthetic rubbers. Conse
quently, an y iron-clad ru le concerning synthetics today m ay prove to be er
roneous tom orrow in view o f the de
velopm ent activity wrhich is sure to take place in the field because of presen t conditions.
The first com mercially successful, and best know n synthetic ru b b er is neoprene which is m ade by the d uP o n t com pany (polym ers o f chloro- prene—several im p o rta n t commercial varieties are being p roduced). Neo
pren e can be p ro cessed . on rubber m achinery w ith nearly as m uch ease as n atu ra l rubber. W hen p roperly compounded and heated, it polym er
izes o r “ vulcanizes” to a product resem bling n a tu ra l soft rubber. I t is b etter than ru b b er w ith respect to :
(a ) Oils
(b) D eterioration by heat, oxygen, and sunlight
(c) F lexing life (d) Gas diffusion
Usually it is less resistan t to w ater than is rubber, b u t it can be form u
lated to yield products th a t are bet
te r than ru b b er is in resistance to hot water. These p roperties of neo
p ren e make it useful (sometimes p r e f
erable to rubber) fo r certain products such as,—
(a) Hose, gaskets, packings (b) Transm ission arid conveyor belts
(c) Boots w here oil is a facto r (d) Soles and heels where an oil condition exists
(e) Tank linings where oil or high tem peratures are encountered, o r both
(f) S o ft roll cover, especially p rin te rs’ rolls
Quite recently neoprene has been made available in semi-liquid condi
tion so th a t it m ay be used as a high solids p a in t o r as a troweling coin- pound. This ty p e o f plasticized neo
p ren e may be of value fo r various corrosive conditions in the p u lp and p a p e r and other process industries.
One very im p o rtan t characteristic of neoprene is th a t a good product can be m ade which is light in color o r even white. This is not tru e of some of the other synthetic rubbers.
B utadiene, a hydrocarbon obtain
able from petroleum o r other sources, will polymerize to yield a rubber-like m aterial. However, much better ru b bers are obtained by interpolym eriz- ing butadiene with other compounds containing an active vinyl group, such as styrene, acrylonitrile, vinylidene chloride, o r other vinyl compounds (E. R. B ridgw ater, Chem. <£■ M et. p.
139, Oct. 1941).
P erbunan o r B una N is a copoly
m er o f butadiene and acrylonitrile.
N ext to neoprene it is the best known synthetic rubber. P erbunan will vul
canize with sulphur ju s t as n atu ral rubber will, and can be made to yield compounds of all degrees of hardness ran g in g from soft inking-roll stocks of 5-10 durom eter up to a very hard ebonite. This synthetic rubber is characterized by the fact th a t carbon black m ust be incorporated if high tensile strength is demanded. A ny so-called P erbunan stock which is light colored is likely to have low ten
sile stren g th and the other properties will be poor also.
P erbunan vulcanizates are very, r e sistan t to aliphatic oils, quite resistant to heat, and have low perm anent set o r good cold flow resistance. These properties, coupled with the fa c t th a t a wide range o f hardnesses can be made, indicate th a t P erbunan could be used as a press roll covering m a
terial fo r p a p e r machines. A good roll cover m ust be well bonded to the m etal core, m ust be resilient and re
sistan t to cold flow', and have the p ro p e r hardness. Methods have been
S y n th e tic ru b b e rs m ig h t b e c o n s id e re d b y c h e m ic a l e n g in e e rs for m a n y u s e s w h e re n a tu r a l ru b b e r h a s su ffic e d
devised f o r adhering this ru b b er to metal. Num erous rolls have been m ade o f the m aterial, but it has not been used as a press roll cover fo r the reason th a t rubber is satisfactory, and also because P erbunan is m ore expen
sive, more difficult to process, and adhesion o f plies presents a problem .
Decker couch rolls covered with P erbunan have worked very satisfac
torily. Possibly the same technique would be applicable to large press rolls. I t m ust be appreciated, how
ever, th a t if attem p ts are m ade to use P erb u n an o r any other synthetic ru b ber in large rolls there will be num er
ous delays in delivery. No doubt m any m istakes will be made before a synthetic ru b b er used as a p ress roll cover can approach the p rese n t high sta n d ard of perform ance o f rubber covered press rolls.
I t will take much tim e and effort to ad o p t the synthetic rubbers to all o f the services of the process indus
tries, m eanwhile it is hoped th a t engi
neers will be sym pathetic w ith rubber m anufacturers. Real cooperation will be needed between the producer and user in order to solve the problem s.
P erb u n an has been used as a ta n k lining m aterial as it is resistan t to acids, alkalis, and water. Its elec
trical p ro p ertie s are not outstanding, b u t are good enough fo r m any p u r
poses. This rubber m ay be used fo r p rin te rs ’ rolls, m otor m ountings, con
veyor belts, gasoline hose, packing, gaskets, and other products. The
CHEM ICAL & M ETALLURGICAL E N G IN E E R IN G • M A R C H W , 2 3— 79
D eck e r c o u c h ro lls c o v e re d w ith P e r b u n a n h a v e w o rk e d v e r y s a tis fa c to rily . P o ss ib ly th e s a m e te c h n iq u e w o u ld b e a p p lic a b le to la r g e p r e s s ro lls
Germ ans say B una reinforced with wire makes gaskets which seal better th a n asbestos and w ork well up to 350 dog. F . No doubt fu rth e r uses can be m ade of it as m ore experience is gained. F rom the ru b b er m anufac
tu re r ’s standpoint, the chief draw back to this m aterial is the difficulty in processing it, since it does not “break down” on a rubber mill in the same m anner as rubber. Nevertheless, methods have been devised fo r h a n dling it. I t has excellent molding qualities.
P erb u n an E x tra is sim ilar to P e r
bunan except th a t it is m ore oil re sistant. I t is a copolym er o f b u ta
diene and acrylonitrile in which a lai’gcr am ount of the la tte r is used.
H y car O.K. is derived from b u ta diene and an undisclosed ingredient.
This synthetic rubber is sim ilar to P erb u n an , except th a t it is m ore re sistan t to oil. Like P e rb u n an it will
yield vulcanizates with a wide ran g e o f hardness (G arey, Juve, Sauser, In d . <£- Eng. Ghem., p. 602, 1941).
Specially com pounded H y ca r O.R.
yields so ft vulcanizates with excellent resistance to heat, both wet and dry.
H y ca r is less resilient than rubber but is sufficiently “ru bbery” fo r m any purposes. In sp ite o f its low resili
ency (in g en e ral), the stocks p ro p erly form ulated show excellent resistance to cold flow. I t tends to stiffen a t low tem peratures b u t can be form u
lated to give com pounds which have good flexibility u n d er this condition.
H y ca r O.R. is reported to give better w ear value as a tire tread than n a tu ral rubber. I t is outstanding in resistance to aliphatic oils. I t has excellent m olding qualities, can be calendered quite easily, and can be bonded to m etal. This m aterial has good resistance to acids, alkalis, and salt solutions (except stro n g oxidizing
ag e n ts). H ence it can be used fo r all the applications previously given fo r P erbunan.
B una S is a copolym er o f butadiene and styrene and resembles n a tu ra l ru b b er to some extent. I t is n o t oil resistant, but does have good resist
ance to abrasion and chemicals, and good electrical pro p erties. This syn
thetic rubber has been very little used fo r mechanical rubber goods, since it is n o t oil resistant, the p rin cip al attractio n of synthetic rubbers hereto
fore. W ith a shortage o f n a tu ra l ru b ber, B una S m ay become a very im p o rta n t synthetic rubber. I t is capable o f yielding vulcanizates o f all degrees of hardness. These vulcanizates resem
ble com pounds of sim ilar hardness m ade from rubber with respect to chemical resistance an d electrical properties. The electrical pro p erties are superior to com pounds of sim ilar hardness m ade fro m P erb u n an , P e r
bunan E x tra , H y ca r O.R., and the neoprenes.
H a rd B una S o r B una S-S could p erh a p s replace the usual products made o f h ard ru b b er such as combs, trays, bowling balls, syringe fittings, b attery containers, etc.
B una S can be bonded to m etal satisfacto rily and hence m ay prove useful as a ta n k or p ip e lining m a
terial to replace ru b b er f o r all chemi
cal solutions w here rubber is now used, nam ely:
(a ) A ll inorganic acids except stro n g oxidizing acids such as n itric and chromic
(b) All inorganic salt solutions ex
cept those which are strongly oxi
dizing
(c) P la tin g solutions
(d) In organic bases, such as so
dium hydroxide
(e) M any organic acids, such as acetic, ta rta ric
(f) P ickling solutions
(g) Chlorine w ater and hypochlo
rite solutions
These possibilities fo r synthetic rubber are of interest to m any indus
tries. F o r exam ple, rubber-lined tanks are widely used fo r pickling steel. The rubber is protected by a brick lining. In the case of stainless steel pickling w here n itric acid is used special rubber com pounds are r e quired, and ru b b er coated w ith p la sti
cized polyvinyl chloride is considered superior in perform ance to the con
ventional types o f ru b b er lining.
Synthetic rubbers, especially neoprene and B una S could p erh a p s be adapted to this service either alone or in com
bination w ith other m aterials.
T ran sp o rtatio n and storage of va
rious acids now handled w ith rubber-
Rubber
C o m p a riso n of P ro p e rtie s
Yields soft or Chemical Oil
hard rubber Resistance Resistance
of S y n th e tic R u b b e rs
Electrical Abrasion H eat Cold Flow Properties Resistance Resistance Resistance Aging
N atu ral... .. All hardnesses Good Very poor Good Good Medium Good Fair
N eo p ren e.. . . Soft only Good Fair Fair Good Good Fair Good
P erbunan___ Fair Excellent to Fair Good Good Good Good
H ycar 0.11— .. All hardnesses Fair
aliphatic hydrocarbons
Outstanding Fair Good Good Good Good
Thiokol... .. Soft only Good
toward aliphatic oils
Excellent Fair Poor Poor Poor Excellent
B u ty l... .. Soft only Excellent
toward aro.
and ali.
Poor, fair to Excellent Fair Excellent Fair Excellent
Runa R ,... .. All hardnesses Good
vegetable ofls and fatty acids
Poor Excellent Good Good Good Good
S O ^ S M A R C H 19J,2 . CHEM ICAL & M ETALLUR GICAL E N G IN E E R IN G
CHEM ICAL & M ETALLURGICAL E N G IN E E R IN G • M A R C H 191,2 . lined equipm ent could be handled with
synthetic rubber. D iscoloration of certain acids by contact w ith th e syn
thetics is a problem which should receive special attention:
The p la tin g in d u stry makes exten
sive use o f rubber-lined tanks, while the synthetic rubbers a p p e a r to have been little used fo r these tanks, some o f the synthetics especially neoprene and B una S have the necessary resist
ance to w ater and to the p lating solutions. A dap tin g one or more of the synthetics would involve te st to determ ine w hether or n o t p la tin g baths would be “ poisoned.” I t seems probable th a t in most cases the syn
thetics could be so compounded as to avoid h arm ful contam ination o f the bath.
In general, synthetics have been used in the chemical in d u stry only where an oil or severe heat condition exists. Obviously, they m ight be con
sidered in m any instances where n a tu ra l ru b b er has sufficed. F o r best resistance to hot aqueous solutions, where oil is n o t a factor, neoprene (specially form ulated) or B una S would be p referab le to the oil resist
a n t B una types. Due to its better aging characteristics it is possible th a t B una S m ight prove superior to ru b b er in certain o f the possible applications indicated.
There are a num ber of polysulphide rubbers known u nder the trad e name of Thiokol. They are m ade from an organic dihalide and sodium poly
sulphide. This group is best known fo r its exceptional resistance to oils—
both aliphatic and arom atic. They are quite resilient b u t have poor re sistance to high tem peratures and severe mechanical stresses. Thiokols are excellent fo r hose, p rin te rs’ rolls, gaskets, self-sealing gasoline tanks, and m any other mechanical goods where good resistance to oil is de
manded. T heir use can be greatly extended if necessary d u rin g the p resen t emergency. They are not good a t high tem peratures and will not w ithstand severe mechanical stresses.
F rom this discussion o f the com
m ercial varieties o f synthetic rubber it is a p p a re n t th a t if all were avail
able in quantity, rubber m a n u fa ctu r
ers could make m any of the articles which are now m ade o f rubber. Some of the synthetic articles would be better, and some would be p oorer than the same articles made of n a tu ra l rubber. F u rth e r investigations o f the processing and com pounding will make it possible to meet m ost of the im p o rta n t requirem ent with synthetic rubber.
R u b b e r in th is e q u ip m e n t m u st re sist th e a c tio n of fe rric c h lo rid e , o n e of the m ost co rro siv e of ch e m ic a ls
. «-
1S y n th etic r u b b e r h o se h a s b e e n m a n u fa c tu re d for s e v e r a l y e a r s
F la x s tr a w p u lp is b le a c h e d in th is ru b b e r-lin e d s p h e re in th e c ig a re tte p a p e r m ill of E c u sta P a p e r Co. a t P is g a h F o re st, N . C,
Iii the accom panying table have been listed the p rin cip al rubbers as well as n a tu ra l rubber. F rom this table it should be possible to choose the. synthetic rubber best suited for a given condition. I t m ust be u n d er
stood, o f course, th a t the tabulation o f p ro p ertie s is quite general and specific com pounding o f any one of th e synthetic rubbers m ight give it a different ra tin g w ith respect to the Spécifie p ro p e rty listed.
Synthetic ru b b er hose has been m anufactured fo r several years, and has been used largely fo r handling gas or oil. This same hose could be m ade and used fo r handling water, acids, an d alkalis. N eoprene would be p re fe rre d f o r high tem p eratu re w ork or w here exceptional w ater r e sistance is a fac to r. Thiokol is su it
able fo r low -tem perature w ork fo r m any services. The B una types could p erh a p s be adapted to hose m anufac
tu re if necessary.
Suction hose could be fabricated from the synthetic rubbers.
Conveyor belts are widely used in the p a p e r in d u stry fo r conveying chips, p u lp , and riot infreq u en tly fo r tra n sp o rtin g logs to and from barking drum s. Coal is also moved on con
veyor belts in the p a p e r and other industries. B elts fo r these services are m ade in various w idths and plies and are rubber covered (all around) to p revent w ater from entering the
carcass and in order to p rotect from im pact, gouging, an d tearing, and to provide a surface a t all p oints th a t will give m axim um w ear value. S yn
thetic ru b b er com pounds have been developed out of which good conveyor belts can be made, in fac t m any have already been made, especially with neoprene.
Transm ission belts in the p a p e r in
dustry are used fo r m ain line sh afts of drive and various general pow er transm ission drives such as found on thrashers, pum ps and beaters. H ere again synthetic rubber com pounds can be used in place of n a tu ra l ru b ber; and in cases where oil is present o r where high tem peratures exist the synthetic can be used to advantage.
The continuous bleaching of p u lp has resulted in a very extensive use of rubber in certain p a p e r mills, chlo
rin e and hypochlorite solutions m ay conveniently be handled in . rubber- lined p ip e and tanks in this continu
ous bleaching operation. Vacuum w ashers are rubber covered, usually w ith rubber o f a hardness from 10-20 plastom eter. Com pounds of suitable hardness, resiliency, and w ith suffi
cient resistance to heat and chemicals can readily be fabricated from the B una types of rubber. Some diffi
culties would p erh a p s arise in ap p ly in g synthetics here, but this ty p e of equipm ent could p erh a p s be ade
quately protected w ith synthetics as
m ore is learned about processing.
F rom the foregoing discussion it a p p e a rs th a t it would be possible to m ake m any pieces o f equipiuent from one o r m ore of the synthetic rubbers. W h a t difficulties will be en
countered in producing all o f these articles, and how they will p erfo rm as com pared w ith n a tu ra l rubber, fo r the m ost p a rt, rem ains to be seen.
S tyrene can be produced fo r 30-35c.
p e r lb. arid acrylonitrile a t 35c. On a large tonnage basis; butadiene could be m ade fo r l0-15c. p e r lb. and th e finished B una ty p e rubbers fo r 20-25c.
p e r lb. H . I. C ram er, S harpies Chem
icals, has p rep a re d an in teresting tabulation showing a t w hat prices the various - synthetic ru b b ers will have to sell in order to com pete with n a tu ra l rubber a t prices- prevailing before our entering the w ar ( Chem.
& M et., p. 150, Ja n . 1942).
U nder present conditions a syn
thetic rubber would not have to com
pete in price w ith n a tu ra l rubber. I f suitable fo r a vital in d u stria l need a synthetic ru b b er could sell fo r several tim es the price o f crude n a tu ra l ru b ber and could sell in larg e volume. I t seems likely th a t in a fre e m arket ru b b er could still sell fo r a p rice well below any of the synthetic rubbers.
The au th o r wishes to th a n k his as
sociates, 0 . S. T ru e and E. D. Hoff, fo r assistance in the p re p a ra tio n o f this pap er.
N e o p re n e a n d B u n a S h a v e th e n e c e s s a r y r e s is ta n c e to w a te r a n d to p la tin g so lu tio n s to b e u s e d io r th e ta n k lin in g
5 2 — 3 M A R C H W f i » CHEM ICAL & M ETALLUR GICAL E N G IN E E R IN G
Mobilizing Petroleum Hydrocarbons
GEORGE F. FITZGERALD
C h e m ic a l E n g in e e r, O le a n , N . Y .— — — — — — — C h e m . & M e t I N T E R P R E T A T I O N -
The petroleum industry, mobilizing its hydrocarbons for use in high- octane aviation fuel, synthetic rubbers, toluene and other products, w ill p la y a vital part in the winning of this war. Just how capable and prepared is the country's largest process industry to m eet these new responsibilities? Can the industry supply by 1943 sufficient raw m aterials for som e 600,000 tons of synthetic rubber and 65 million barrels of 100-octane aviation fuel? Herein the author answ ers this question and gives som e interesting aspects of the problem.—
E ditors.D
e m a n d f o b petroleum products in 1941 was the greatest in the 80-year history o f the in d u stry and exceeded the previous y ea r by ten p e r
cent. A t the end of last y ea r, daily crude oil production had reached 4,100,000 bbl. O u tput is expected to reach 4,500,000 bbl. by the middle of this year and five million by Ju ly 1943. In the face of an acute rubber shortage, it is interesting to speculate th a t one day’s crude oil production is equivalent on a hydrocarbon basis to our annual crude ru b b er consumption.
The P a r E astern situation now presents the oil refining in d u stry w ith a form idable proposition. W ill it be possible to guaran tee adequate stocks o f 100-octane aviation gasoline arid, in addition, meet an entirely new de
m and fo r synthetic ru b b er ingredi
ents? I t m u st be remembered th a t A m erican refineries are supplying fuel to all the Allied nations as well as to ou r own g reatly expanded air forces.
The su p erio rity of 100-octane fuel has won it complete acceptance by all fighting forces. W eight fo r weight, it yields 20-25 percent more pow er than 90-octane fuel. This means lighter fuel load and lighter engines p er de
livered horsepower. These advantages p erm it higher operating speeds, big
g er p a y loads and w ider radius o f op eration. I n spite o f these advantages the suggestion has been made th a t aviation fuel quality be dropped to 90-octane to release stocks fo r syn
thetic rubber.
A m erican 100-plus octane fuel is a blend of light straig h t-ru n petroleum
fractions, alkylation products and catalytically cracked gasolines plus tetraethyl lead. A rom atics also m ight come into use as they have been found satisfacto ry in England. According to Refining D irector W . W . Gary, an acceptable fighting grade fuel fo r the A rm y and N avy m ay be 100 o r 100- plus octane ra tin g to be blended a p proxim ately as shown in Table I.
FIG H TIN G GRADE FUEL B efore P earl H arb o r, the Office of Petroleum C oordinator estim ated th a t our defense program would require the expansion of fighting grade fuel capacity to 126,000 bbl. p e r day be
fore the end of 1942. A m onth la ter the figure was raised to 180,000 bbl.
p er day. By contrast, la st y ea r’s out
p u t reached a peak between 45,000 and 50,000 bbl. p e r day, which is more than all th e re st of the world p ro duces. The O PC has concentrated on m aking every move count tow ard in
creasing o utput and capacity a t the utm ost speed. One o f its most im p o rta n t efforts was the Petroleum H ydrocarbon S urvey which deter
mined the quantities and types o f hydrocarbons available from the oil industry. These figures will be of especial value now in locating sources o f high-octane fuel, butadiene and styrene.
The call fo r synthetic ru b b er bases from petroleum sources m om entarily ap p e ars to jeopardize the o u tp u t of 100-octane gasoline. To arriv e a t an understanding o f the situation as it affects the refiners requires an analysis of w artim e dem and fo r ru b
ber and fuel an d a study of po ten tial and actual sources of raw m aterials suitable fo r both. I t is th e purpose of this article to outline the processes and capacities available fo r the m anu
fa c tu re o f butadiene and fighting grad e aviation gasoline.
According to Table I we would need ap proxim ately 90,000 bbl. p e r day o f 80-100 octane blending agents to meet the OPC program . O f this am ount about h alf m ight come from catalytically cracked gasoline and the rest from alkylates and liydroco- dimers. The la tte r two stocks m ust be made from butane bases and conse
quently will be in direct com petition w ith raw m aterials fo r synthetic ru b ber.
P rin c ip a l sources o f butane and isobutane are the n a tu ra l gasoline and gas recycling p la n ts o f the Southwest.
V ast quantities o f petroleum gases from the high pressure fields are passed through absorption towers and fra ctio n atin g columns to remove
“n a tu ra l” gasoline and the C3, C4, and Cr, fractions. T ypical analyses are shown in Table I I . The lean gas from these recycling p la n ts is retu rn ed to the oil-bearing sands to help m aintain reservoir pressure. This country’s 160-odd n a tu ra l gasoline p la n ts alone when o p eratin g a t full capacity can tu rn out approxim ately 2,000,000 gal.1 of b utane-propane m ixture daily.
Refineries also produce large volumes o f these gases b u t usually n o t enough even fo r th eir own blending needs.
Texas has 58 p la n ts which produce 43 percent of the country’s o u tp u t of liquefied petroleum gases. I n 1939 the total was 223,500,000 gal. which rose to 300,000,000 gal. in 1940 o r a gain o f 32 percent. The bulk o f p r o panes and b utane now go to the bot
tled gas m arkets and into in dustrial fuel. I t is in domestic use th a t they are most a p t to be curtailed fo r gov
ernm ent purposes. In 1941 there w ere over a m illion re ta il customers fo r bottled gas. The poten tial liquefied
T a b le I— T y p ic a l 1 0 0 -0 c ta n e G a so lin e B lend
5 0 % b l e n d i n g a g e n t <88-100 o c t a n e ) 4 0 % b a s e s t o c k s (7 5 o c t a n e ) 1 0 % i s o p c n t a n e
T e t r a e t h y l l e a d c o n t e n t n o t to e x c e e d 3 cc.
p e r g a l.
CHEMICAL & M ETALLURGICAL E N G IN E E R IN G • M A R C E 191,2 3— 83
petroleum gas su p p ly is in the neigh
borhood o f 33,000,000 gal. p e r day.
The larg est condensate recovery recycling p la n t in the world’ recently com pleted in Texas handles 225,000,- 000 cu. ft. o f gas daily. The original p la n called fo r recovering 50 percent of the available butane and isobutane content but the expanded arm am ent program m ade it advisable to increase the design yield to 85 percent. B uild
in g ’m ore such p la n ts and g reatly in creasing crude runs are n o t necessarily the answers to w artim e demands.
E x istin g absorption p la n ts could in crease th eir yields by m odernization and im proved supervision. By so do
ing they could m ake available u p w ards of 30,000 bbl. p e r day addi
tional butane. The noticeable decline in domestic consum ption of m otor fuel p lu s the proposed reduction of its butane content will release alm ost twice as much more. As in m ost m a n u fa ctu rin g fields, the system atic reduction o f waste will result in im p o rta n t savings.
MIXED BUTANES
Such m easures could m ake avail
able 90,000-125,000 bbl.3 p e r day of mixed butanes in less tim e and more economically th a n ' by building en
tirely new p lan ts. The technical p ro b lems involved are by no m eans diffi
cult. The chief obstacle is the tim e element in erecting sufficient rectifica
tion and absorption equipm ent to modernize the existing p la n ts and augm ent th e ir o utput. In converting these butanes to alkylates and hydro
codimers fo r aviation fuel heavy losses are encountered. On th e basis of an ap p ro x im ate 60 percent overall yield 75,000 bbl. p e r day would be sufficient f o r 45,000 bbl. o f high- octane blending agents. B y difference, then, there should be from 15,000- 45,000 bbl. p e r day o f butane avail
able fo r ru b b er production.
Am ount o f synthetic ru b b er needed m ay best be gaged by considering o ur norm al consum ption o f crude rubber. In 1940 the value of all m anu
factu red ru b b er goods reached $940,- 000,000 while the crude ru b b er de
m and exceeded 600,000 long tons.*
W ith conservation m easures now in effect, the estim ated maximum of
T a b le II
R a w M id c o n tin en t P e tro le u m G a s T y p ic a l P e r c e n ta g e A n a ly s e s
A B
M e t h a n e ... 2.5 0 2.75 E t h a n e ... 7 .5 0 9.25 P r o p a n e ... 21.6 0 10.70 I s o b u t a n e ... 5.0 0 8.00 n - B u t a n e ... 2 7 .0 0 34.00 P e n t a n e a n d h e a v i e r . . . . 3G.40 35.30
800,000 long tons fo r 1941 is expected to drop to about 400,000 tons by the end o f 1942.
CRUDE RUBBER STOCKS I n a recent statem ent Jesse Jones, S ecretary of Commerce, announced5 th a t our stockpile o f crude ru b b er was over a million tons o r about two y e a r’s su p p ly fo r arm y and navy needs. The U nited S tates received about 114,000 tons from th e P a r E a st in Ja n u a ry and a sim ilar am ount in tra n s it was expected to arriv e here in F eb ru ary . N atu rally no fu rth e r shipm ents from M alaya will be m ade while the J a p s are in possession. R e
claim ed ru b b er u p to 50 p erc en t is used to extend the crude supply, but our scrap pile will la st only 12-18 months w ith tire ratio n in g in effect.
These figures definitely show th a t we have approxim ately a y ea r and a h a lf in which to im prove our rubber output. Guayule from the M exican shrub has been advanced as a possible solution. W e now obtain about 4,000 tons o f guayule annually b u t fo u r to six y ears would elapse before th a t figure could be substantially in creased. South A m erican ru b b er p ro duction likewise calls fo r long-term developm ent w ith no im m ediate in crease in tonnage. W e are brought a b ru p tly to 'th e realization th a t syn
thetic ru b b er m ust m eet the demand and th a t synthetic production m u st be step p ed up to 300,000-400,000 tons fo r w ar purposes alone in m uch less than two years.
SYNTHETIC RUBBERS
I t is outside the scope o f this article to discuss synthetic rubber production from th e process angle.
O ur concern is w ith the types and quantities o f raw m aterials needed with p a rtic u la r em phasis on p e tro leum derivatives. W ith several com
m ercial types o f synthetic ru b b er on the m arket, the governm ent is de
pending largely on th e neoprenes and the butadiene polym ers because of th e ir su p erio r w ear characteristics.
F o r m ilita ry purposes in general ru b ber m ust m eet the requirem ents of good tire tread m aterial. In this respect thiokol, polysulfide rubbers, polyisobutylenes and others, while very im p o rta n t in specialized fields, are not equal to chlorprenes and b u ta
diene polym ers. I n its $400,000,000 building pro g ram , the governm ent is p u ttin g the greatest em phasis on the butadienes. The “B una S ” ty p e has been adopted as sta n d ard fo r w ar production. The butadiene is p ro duced from petroleum , n a tu ra l gas, alcohol o r acetylene. The styrene can
be m ade fro m benzol derived from coke-oven operations.
D r. E. R. W eidlein, C onsultant, Chemicals B ranch o f W P B , an nounced to th e oil in d u stry in F e b ru a ry th a t it was necessary to pool all p aten ts, resources and technical ex
perience with th e rubber an d chemical m an u factu rers i f we are to ca rry out the rubber program . H e stated th a t raw m aterials fo r the first h a lf o f th a t p ro g ra m are in sight and are to come largely from chemical industry. F o r the second 200,000 tons the petroleum in d u stry is expected to fu rn ish the necessary base stocks.
I t is obvious th a t an ab u n d an t su p p ly o f acetylene, butadiene and styrene will be needed to expand syn
thetic ru b b er production from an esti
m ated 90,000 tons before this y e a r is over to 400,000 tons p e r y e a r in the next 18 months. The la tte r quantity is equivalent to a theoretical con
sum ption of 11,000 bbl. of butane p e r day. This is well w ithin the bal
ance o f 15,000-45,000 bbl. le ft a fte r earm arking sufficient am ounts fo r 100-octane gasoline production. As would be expected, however, theo
retical yields are n o t obtained. Higli conversion losses and side reactions will probably b rin g the ultim ate de
m and u p to 35,000 bbl. p e r day3 or very close to ou r w orking balance.
This dem and, o f course, will be r e duced to the extent th a t sizable am ounts of ru b b er will be produced from bases other than butadiene.
Should unforseen circum stances re quire much additional b utane it would be necessary to build additional butane recovery p la n ts and fu rth e r re stric t civilian supplies. One possi
bility which is feasible b u t probably n o t strategically sound is th e reduc
tion of fighting grade gasoline to 90- 95 octane ratin g . This would release 70,000-80,000 bbl. o f butane p e r day.
Such a step would call fo r a m ilita ry choice between ru b b er and 100-octane fuel.
ACETYLENE AND BUTADIENE Acetylene production fro m p e tro leum is u n d er developm ent by re search w orkers a t the U niversity of Texas. They re p o rt th a t it has been m ade experim entally fro m p ro p an e b u t has n o t yet reached the commer
cial stage. E x istin g facilities fo r the synthesis o f butadiene fro m petroleum gases are being rap id ly augm ented.
T ypical of th e new facilities is a 5,000 to n-per-year u n it which w ent into p roduction la te in 1941. S everal more p la n ts are u n d er construction b u t de
tails m ust be considered as m ilitary secrets a t this time.
8 4 — 3 • M A R C H 191,2 . CHEM ICAL & M ETALLUR GICAL E N G IN E E R IN G
CHEM ICAL & M ETALLURGICAL E N G IN E E R IN G • M A R G E 19Ą2 3— 85
Courtctty R obert Y arn all R ichie
100-octane fig h tin g fu e l c a n b e m a d e b y c a ta ly tic a lk y la tio n of iso -b u ta n e a n d b u te n e to iso -o c ta n e in p la n ts lik e th e o n e s h o w n h e re
M any o f the steps involved in butadiene synthesis are fam iliar to m an u factu rers o f 100-octane gasoline, who fo r years have been using a series of therm al and catalytic proc
esses’1. I t m ay be o f in te rest to sum m arize these and note p ara llel a p p li
cations. B oth reform ing and cracking convert b utane to butylene, which may be fu rth e r dehydrogenated to butadiene. Or it m ay be combined w ith an olefin by alkylation fo r a high-octane blending agent. The necessary b utane is obtained by ab
sorption and fractionation from n a tu ral gas and refinery cracking still gases. In the la tte r case isobutane and butylene are also recovered.
H y d ro fo rm in g combines dehydro
genation w ith arom atization, tising s tra ig h t ru n or catalytically cracked nap h th as as charging stock. The con
version takes place in an atm osphere o f hydrogen a t elevated tem peratures an d pressures. The pro d u ct represents an 80 percent yield o f 80-octane gaso
line containing a high percentage o f arom atics. O peratin g conditions can be modified so as to produce 80 p e r
cent arom atics rich in toluene. P o ly form ing is an analogous process which uses butane or p ro p a n e vapors instead of hydrogen.
A lkylation com prises jo in in g an iso-paraffin with an olefin (u n satu ra te d ) hydrocarbon. I f iso-butane and butylene are taken as charging stocks the product is iso-octane, the most im p o rta n t available blending agent fo r 100-octane aviation gaso
line. The cataly st is 100 percent sul
phuric acid and the charge usually consists of the butane-butylene m ix
tu re from a cracking o r dehydrogena
tion p la n t plus additional isobutane from an absorption p la n t or an isom erization process. S ulphuric acid alkylation was developed alm ost sim ultaneously by several companies who have pooled th e ir interests. The process is the best available fo r a high yield o f 100-octane fuel p e r u n it charge of olefin. P y ro ly tic alkylation of ethylene-butane m ixtures yields neohexane which tests 94 octane w ith
out lead and 115 octane num ber a fte r the addition of 3 cc. tetraethyl lead p e r gal. o f gasoline.10
ISOM ERIZATION
Isom erization is a very im p o rta n t ad ju n ct to alkylation. In relation to our presen t discussion, this is the fa c to r which p u ts aviation gasoline in close com petition w ith synthetic ru b ber fo r the available butane supply.
Refinery gases as fed to an alkylation p la n t are usually deficient in isobu
tane and often too rich in n-butane, which acts as a diluent. Norm al butane from m any sources is re la tively ab u n d an t b u t was useless in alkylation until the p erfection o f th e isom erization process fo r converting it to the active branched-chain form . U ntil th a t tim e a lim ited am ount was blended into gasoline and the g rea ter p a r t went to the bottled gas m arket.
I n commercial operation the process results in alm ost com plete conversion of norm al butane to isobutane.
B utane vapors mixed w ith dry hydro
gen chloride gas are passed through a cham ber packed w ith an alum inum chloride catalyst su p p o rted on in e rt g ra n u la r m aterial. The hydrogen chloride serves to activate the catalyst and is entirely removed from the finished product. The reaction p ro d uct is passed through a refrig erate d condenser and thcnce to a hydrogen chloride strip p in g column. The acid vapors are recycled to th e process and the acid-free bottom s are ready fo r alkylation.
CATALYTIC POLYMERIZATION C atalytic polym erization is com
m ercially ap p lied to propylene and the butylenes to form liquids in the gasoline boiling range. Phosphoric acid and copper p y rophosphate are m ost widely used as catalysts. O p erat
ing tem peratures ran g e from 300- 400 deg. F u nder pressures from 700- 1,100 lb. depending upon the p a rtic u la r process in use. The pre-heated charge is fed to the cataly st cham
ber and then to a stabilizer u n it w here the desired p ro d u ct is fractionated.
C atalyst tem peratures m ust be closely controlled. Two catalyst chambers are provided so th a t one m ay be dum ped and recharged while the o ther is in service. E xhausted catalyst is discarded. C atalyst life averages 90 gal. of polym er p e r pound o f catalyst with 85-95 percent conversion to a p ro d u ct which tests 84 octane b u t has a blending value equal to 110-130 octane ratin g .
CATALYTIC CRACKING H o u d ry catalytic cracking gives high yields o f 80-octane gasoline from distillate fuel oil (gas oil). The p ro d uct, which is highly suitable fo r blending to 100-octane, is obtained w ithout draw ing upon our v ita l su p p ly o f butanes and butylenes. C ata
lytic dehydrogenation is ap plicable to both synthetic rubber and aviation fuel. I t is o f immense im portance fo r increasing our su p p ly o f selected olefins. Of these la tte r, ethylene from ethane is therm ally alkylated to neo-.
hexane as already pointed out.
T a b le III— D e riv a tio n of P rin c ip a l S y n th e tic R u b b e rs
P r i n c i p a l S y n t h e t i c R u b b e r R a w M a t e r i a l s B u n a S ... B u ta d ie n e S ty r e n e B u n a N ... B u ta d ie n e
H y c a r ) A c r y lo n itr ile
C b e m lg u m )
B u ty l ... B u ta d ie n e I s o b u ty le n e N e o p re n e ...C h lo ro p re n e V is ta n e x ... Is o b u ty le n e K o ro s c a l ...V in y l c h lo rid e T h io k o l A . . . ... E t h y l e n e d ic h lo rid e S o d iu m te tr a s u l p l i i d e T h io k o l B ... D ie h lo re th y l e t h e r S o d iu m te t r a s u l p h i d e
SG— 3 • M A R C H 19Jß . CHEM ICAL & M ETALLUR GICAL E N G IN E E R IN G
