Benzene—Supply and Demand K. W . S I T L L I V . \ N , J R . , 139 R i d g e d a l e A v e . , M a d i s o n , N . .J.
T h e p r e s e n t s h o r t a g e of b e n z e n e f o c u s e s a t t e n t i o n o n p r o d u c t i o n and u s e o f t h i s b a s i c c o m m o d i t y » . α I t appears t h a t t h i s deficiency is p e r m a n e n t a n d w i l l b e c o m e e v e n m o r e a c u t e . . . A r e v i e w o f t h e s i t u a t i o n is i n order to s h o w h o w t h e shortage h a s c o m e about a n d what s l e p s should be taken to m i n i m i z e future consequences
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Uydroforming unit of the toluene plant* tiny town, Tex., Ordnance Works 1> tlic United Status, the product ion of coal-tar benzene and its derivatives in sig nificant amounts began in 1915. These products provided the raw materials for high explosives and for the dyes and other products which had been obtained from Germany. The figures for the production of light coke-oven by-products and impor tant derivatives from 1915 to 1946 are plotted in Figures 1 and 2, the first present ing the data on coal-tar light oil and crudes, and the second, the data on the most im portant cyclic intermediates. After the first world war, the production of toluene and phenol which had been used almost exclusively for the explosives TNT and picric acid, dropped precipitately al most to nothing and the production of oenzene dropped sharply. After the sec ond world war, while again the production of toluene dropped sharply to the prewar level because it had again been used largely for TNT and other military purposes, the production of aniline, phenol, styrene, and cyclic intermediates generally has con tinued at the wartime level. Although the production of benzene dropped, this was due to strikes in the coal and steel in dustries. Had it not been that almost half of the benzene produced during the war was allocated to aviation gasoline manu facture and that this benzene became avail able for industrial requirements after the war, the supply situation would have been even more critical. The Department of Commerce, Bureau of the Census, published in its "Facts for Industry" series a page on "Benzene in the War Program (/)." This is repro duced in Table I. Table II presents a com parison of the allocations according to this source with the production as reported by the U. S. Tariff Commission. The ratios of actual to theoretical yields for phenol and aniline have been used 2000
later to calculate the benzene required for the production (if these materials. In the case of styrene, a yield of 82 r f of theory is believed to be closer to that actually experienced and this figure has been used in determining the equivalent benzene. The best estimates which can be made on the use of benzene for the production of miscellaneous chemicals from benzene during 1944 are given in Table III. No data are available on the production of the "phthalate piastieizers, anthraquinone, resorcinol, alcohol dénaturant, small orders and other miscellaneous uses" which are said to account for "all other miscellaneous chemical uses" of benzene shown in this table. The consumption of benzene in Germany during the war followed a similar pattern to that which prevailed in this country except that the allocation for fuel was negligible in comparison with the allocation for this purpose here. Using the yield factors given in Table II
and other estimated factors of similar magnitude to determine the benzene equivalents of the benzene derivatives reported in the "Facts for Industry" series of the Tariff Commission and approximating the remainder, the requirements of benzene to yield the derivatives produced in 1946 have been estimated and are given in Table IV. The figures for benzene production, 127 million gallons, and the figure for the amount required to make the products reported, 120 million gallons, are in very satisfactory agreement considering the uncertainties involved in the estimates, and are in accord with the reports of shortage of benzene.
Fig. 1. Production of coal tar9 oily benzene, motor benzol, toluene—1915—46
Fig. 2. Production of cyclic intermediates, aniline, phenol, ami styrene—1917-46
.970
light and
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ENGINEERING
NEWS
blast furnaces and, consequently, there is a close relation between general industrial activity, blast furnace operation, and byproduct production. There has been a surprising uniformity over the years in such figures as the average yield of cob from coal, 70 to 7 1 % ; of coke consumed per ton of pig iron, 1,800 to 1,S40 lb.; and of light oil per ton of coal, about 2.85 gal. The facts that benzene originates from this one source, that statistics are available over a long period, and that the relative amounts of the products are fairly constant make the estimation of benzene production quite reliable. To indicate thesituation during 1947, it has been assumed that blast furnace operation and, consequently, by-product coke production, will proceed at the rate prevailing during July to October 1946, a period of normal postwar production not affeetod by strikes in the steel or coal industries. It has also been assumed that light oil production will be normal and that, under the spur of present high benzene prices, the recovery of benzene from light oil will be as high as it was in 1944 under government allocation—that is, 5 7 % . It has been assumed further that the production of benzene by tar distillers will proceed at the average rate prevailing in July through October 1946. The results of these calculations are presented in Table V and show an estimated production of industrial benzene of 161,300,000 gal. which exceeds 1946 production by over 30 million gal. or about 25%. It appears that this should be adequate to provide for the needs of 1947. While it is anticipated that natural rubber will be imported in increasing quantities with consequent reduction in the requirements of styrene for GR-S synthetic rubber, it seems probable that, for 1947 at least, the production of polystyrene plastics will consume any available styrene. This wiLl mean that benzene requirements for styrene will not decrease in 1947 except to the extent that the catastrophe at Texas City reduces Monsanto's requirement. This may amount to a million gallons per month for as long as a year. The demand for benzene for aniline is fairly stable and no marked increase is expected. The same is true for the chlorinated benzene derivatives and other miscellaneous products derived from benzene. Even if i t is possible to meet the 5 0 % increase in demand for phenol for plastics, an unlikely possibility, there should be sufficient benzene available to supply the approximately 9-million-gallon requirement for this purpose and still meet any anticipated expansion of other demands during 1947.
Table I.
Allocations of B e n z e n e :
2 5,
NO.
28
%
J A N . 1J U N E 30, 1945
J U L Y 1EC. 31, 1944
JAN. 1 J U N E 30. 1944
116.865 100.0 371,846 Total 1 allocations0 118,714 136,267 Direct military 42 0.5 638 1 ,S68 1,188 b S8 Foreign 23 45 20 Other uses 118,649 99.5 369,890 115.632 135,609 c 45,707 Aviation gasoline 47.1 175,630 58.177 71,746 30,830 Styrene 21.7 80,561 22,300 27,431 14,422 PtTenol 10.7 39,911 13.375 12,114 6.0 9,374 Aniline 22,208 6,066 6.768 2 . 5 3,982 OHiorobenzene 9,403 2,213 3,208 2,446 2.2 Solvents 8.124 2,508 3,170 1.0 981 Di phenyls 3,574 1,432 1,161 608 0.6 M edicinals 722 770 2,100 0.4 643 Solvent blends* 1 733 1,376 710 507 401 0.4 Nitrobenzene 1,618 347 Rubber chemicals 300 290 0.3 937 0.1 246 74 Trie hlorobenzene 74 98 6.5 Miscellaneous uses* 8,834 24,202 7.755 7,613 " Knd-use data not available. > 'c Less t h a n 0 . 1 % . Includes military aviation fuel. '' Blends a s defined and controlled b y Order M-150. * Includes benzene used in manufacture of nylon, phthalate plasticizers, tnaleic anhydride, camphor antbracjuinone, resorcinol, alcohol d é n a t u r a n t , small orders, and other miscellaneous uses n o t specified Quantities used in nylon comprise a substantial p a r t of t o t a l . No benzene was allocated for manufacture of a u t o m o t i v e fuel during this period. Source: Facts for I n d u s t r y , Bureau of the Census, Series 6 - 8 - 2 .
Tnfc>le II.
Comparison of Benzene End-Use Allocations with P r o d u c t i o n for 1945 ALLOCATION OF B E N Z K N K "
(Ή KMICAL
PRODUCTIONTHEORETICAL ACTUAL''
RATIO OF ACTUAL TO THEORETICAL YIELD
Lb. Lb. Gal. Lb. 0.72 49.731,000 364,000,000 349.367.000 486,000,000 173,141.000 0.78 25,489,000 185,000.000 222,000,000 Phenol 89,130.000 0.81 12.834,000 93,688,000 111,000,000 A. nil i ne a Facts for Industry, Dept. of Commerce, Bureau of t h e Census, Series G 8 2. Set* also Minerals Year Hook, 1945, Coke and By-Products. C h a p t e r (preprint) page 57. b U. S. Tariff Comm., Synthetic Organic Chemicals, Report 155, Second Series. ί-tt y rent-
Table i l l . CHEMICALS
P r o d u c t i o n of Miscellaneous Chemicals in 1911 PRODUCTION
Nylon* 45,000,000 Dodecylbenzene Sodium sulfonate*» 11,000,000 Maleie anhydride 7,800.000 All other miscellaneous chemicals.
ASSUMED YIELD, %
80 70
ΒENZENt EQUIVALENT
6,200,000 425.000 1.320.000 7,423.000
Total allocation of benzene to miscellaneous chemicals· 15.3 68.000 A'etc York Times: Aug. 22, 1945, p. 26; Aug. 23, 1945, p. 27; Nc 2. 1945. p. 16; M a y 19. 1946. Sec VI. p. 3 8 ; Aug. 7. 1946, p . 7. b Assume t h a t all of the "all other cyclic surface active a g e n t s " produced in 1944 fall in thi* «-ategory giving the maximum possible result. tt
seem to indicate that styrene would con tinue at a high level even at present berizeue prices. For all practical pur poses, styrene is irreplaceable in elasto mers of the GR-S type and polystyrene is a, fundamentally cheap thermoplastic
Long-Term Estimate T h e situation for the longer future with respect to the adequate production of byproduct benzene at prices such as have pie vailed in the past is, however, very dark. Consideration of all available data would V O L U M E
J a n . 1, 1944, to J u n e 30, 1945
(Thousands of gallons) TOTAL Amount
JULY
14
19 47
at any probable price for benzene. In the classes of products where aniline is used, principally rubber chemicals, dyes, and medicinals, the total production is not large and the unit values are high so that increases in cost of benzene will not mark edly affect product costs. It is believed that benzene will always be available in sufficient quantity to meet this require ment. In 1945 phenol-formaldehyde resins constituted only 12%, and all tar acid resins only 24%, of all plastic materi als. Nevertheless, allocations for resins amounted to two thirds of the phenol for domestic nonmilitary uses. It would seem that, in the future, phenol-formaldehyde resins would tend to lose position to other plastic materials where there is no funda mental shortage. While greatly increasing production of nylon is forecast, it seems probable that the raw material for this will be cyclohexane isolated from petroleum rather than as in the past, the product of the hydro génation of coal-tar benzene. There are, of course, alternative syntheses which do not involve cyclic raw materials. Du Pont has contracted with the Quaker 2001
Table IV. P r o d u c t i o n o f B e n z e n ^ a n d P r o d u c t s D e r i v e d f r o m B e n z e n e , 194()'' CHEMICAL
PRODUCTION
Styrene Phenol Aniline Dichlorobenzene DDT All other
1,000 lb. 375,000 199,000 89.000 43,500 (
