The picture story above is symbolic of the sequence of events when a butadiene explosion occurred at Polymer Corp., Ltd. After the explosion (upper left), laboratory detective work was begun to find the cause (upper right). Once cause of the blast was determined, it was duplicated on a laboratory scale (lower left), and precautions were worked out to prevent explosions in new butadiene storage vessels (lower right)
I
D. S. ALEXANDER Research and Development Division, Polymer Corp., Ltd., Sarnia, Canada
Explosions in Butadiene Systems
AT 10:25 on Sunday, May 6, 1951, an explosion ocAPPROXIMATELY
P.M.,
curred in the butadiene extraction plant at Polymer Corp., Sarnia, Ontario. The explosion was heard generally 5 miles from the plant and up to 50 miles in isolated locations. I t was accompanied by a mushroom of flame which ascended approximately 100 feet above ground. Windows were broken in many plant buildings and offices and in some houses up to 2 miles from the center of the explo-
sion. No one was killed or seriously injured ; two men were sent to the hospital for treatment of burns to hands and face after running to safety through patches of flame. Operations in the butadiene extraction plant were resumed May 30, 1951. The final cost of replaciag or repairing damaged equipment was $300,000; loss of hydrocarbons, solvent, and other chemicals was estimated at $200,000.
Butadiene Extraction Plant The butadiene extraction plant uses a conventional countercurrent turbomixer settler system with cuprous ammonium acetate solvent to extract butadiene from a C d hydrocarbon mixture. The butadiene vapor desorbed from the cuprous ammonium acetate is washed to remove ammonia, liquefied by compression, and distilled to remove impurities. During the first 6 years after the plant VOL. 51, NO. 6
JUNE 1959
733
A
h A
Spent C4 Settler
\ B
Solvent Make -up Drum
Butadiene Accumulator
m Rejection Settler
DAMAGE Slight. (Impact)
Complete (Impact and Fire)
Complete (Exploded)
Complete (Impact)
Mixer -Settler Units
Figure 1.
The explosion originated in the partially filled accumulator
was built, the procedure was to accumulate the purified butadiene in one of three 1000-barrel drums ( A , B, and C, Figure l), which were filled and emptied successively in order to measure the butadiene. When one drum was full, the flow of butadiene was diverted to the other drum; the contents of the first drum were sampled, analyzed, and, if sat-
isfactory, transferred to 5000-barrel storage spheres. I n May 1950 the procedure was changed; the purified butadiene was pumped continuously through one of the 1000-barrel drums, C, which was maintained partially filled, and thence to the storage spheres. Drums A and B were used for preparing solvent and handling spent Cq. I t was from the
Figure 2. Rate of flow of butadiene from C increased as the pressure increased rapidly prior to the explosion
7’34
INDUSTRIAL A N D ENGINEERING CHEMISTRY
partially filled accumulator C, that the explosion originated. General Damage
A plot of the area in which damage by blast was severe is shown in Figure 1. Drum C exploded and disintegrated ; B and D were completely demolished by impact; damage to A , E, and F was slight. The head from the east end of accumulator C was blown clear of the unit about 75 feet to the east. This head was expanded into nearly spherical shape and the diameter of the section was found to be 9 inches oversize. A large portion of the 4-inch nozzle of the safety valve on C was hurled 3000 feet north; the paint on this projectile showed no sign of heat. The neighboring drum, settler D, appeared to have been weakened and damaged by impact and disrupted by internal pressure. A hole 12 inches in diameter was punctured in the 3/4-inch thick plate of settler E by a flying piece of piping. Eyewitness Accounts. All sections of the plant were operated under steady and normal conditions during that day, and possibly up to just after 1O:OO P.M., when the last set of readings were logged. At approximately 10: 15 P.M., the pressure in the butadiene accumulator, C, started to rise; the flow of butadiene from the distillation section to C decreased, and the flow of butadiene from the drum to the storage sphere increased (Figure 2). The safety valve on C opened and a heavy discharge of vapor occurred to the flare stack. When the sky lit up from the flare stack, one of the refrigeration engineers was outside approximately 200 feet northwest of drum C. He heard a sharp report like a compressor backfire and saw a nearby line fall, enveloped in small flames. Almost immediately there was a second and much more violent explosion, and flame mushroomed overhead and beyond him, as he ran to the west. He and other witnesses noticed showers of burning particles; next morning pieces of partially burned popcorn polymer were found distributed over a wide area. Major fires in the blast area and two secondary fires raged until midnight and the area near the remains of drum C continued to burn until morning. KOother positive evidence was found. Subsequent examination of fragments indicated no signs of flaws or faulty construction in drum C. Pieces thrown clear of the fire zone showed no signs of exposure to high temperatures. Uninhibited butadiene had been flowing through drum C. Because the vapor space could have trapped traces of oxygen in the reconstructed plant the butadiene was inhibited with tert-butyl catechol in the rerun towers, then pumped directly to storage spheres. As no further progress could be made with available evidence, the laboratory
BUTADIENE EXPLOSIONS staff undertook to determine the means by which explosions with butadiene could be reproduced on a small scale. Three Theories I t was thought that drum Ccould have ruptured by the vapor pressure of butadiene, which had been raised by the heat liberated by rapid polymerization of butadiene initiated by traces of peroxides. Drum C, a 40,000-gallon vessel, contained about 15 volume yoliquid at the time of the explosion. Assuming a heat of polymerization of 17.6 kcal. per mole, adiabatic polymerization would result in a maximum of 430 p.s.i. at 4070 conversion of the butadiene. The rated bursting pressure of the drum was 700 p.s.i. and there was no reason to suspect premature failure of the metal. The second theory was that adiabatic polymerization had raised the temperature and pressure to levels a t which a portion of butadiene itself had decomposed explosively, in a manner similar to that well known for acetylene, and reported for ethylene (73) and propylene (7). A suspicion that butadiene could behave in this manner was expressed in 1940 (72). A destructive explosion in an autoclave containing crotonaldehyde and butadiene was reported in 1948 (4). A 1949 report (70)mentioned unsuccessful attempts by Carbide and Carbon and Du Pont to cause spontaneous decomposition of butadiene, using fulminate detonators and hot wire techniques. Two investigations showed that butadiene a t 800' C. and about 20 mm. of mercury pressure were reasonably stable (8, 74)in the absence of oxygen. Both the above theories assumed the presence of peroxides for initiation of polymerization. Robey, Wiese, and Morrell(9) had shown that butadiene reacts with oxygen to form liquid peroxides, which themselves are unstable and explosive. Butadiene flowed into drum C a t the top of one end and out a t the bottom of the same end. I t seemed possible that peroxidic material could accumulate in a liquid layer a t the bottom of the drum, particularly if it were insoluble and more dense than butadiene. It was decided to construct an apparatus in which butadiene and oxygen could be subjected to a wide range of temperatures and pressures, and the characteristics of the reactions and the products of reaction studied. O n October 24, 1952, the problem was discussed with Kharasch and Nudenberg, University of Chicago, who recommended that the reaction system should include polymerically active and inactive butadiene popcorn polymer. Butadiene popcorn is a highly cross-linked, internally strained, translucent, solid butadiene polymer, waterwhite to yellow. Both oxygen and buta-
I
This is the amazing story of how Polymer Corp., Ltd., chemists and chemical engineers traced the cause of a butadiene explosion to butadiene peroxide formation, reproduced the explosion on a small scale, and finally worked out a method for minimizing the hazard. It may well be a modus operandi for others, in different fields, seeking the causes and methods of preventing similar disasters
diene are soluble in the popcorn, which probably accounts for the internal stress and, depending on the oxygen or peroxide concentration, the polymeric activity of the solid. Butadiene popcorn can grow by polymerization of the butadiene inside the solid with such expansive force as to rupture heavy-walled steel equipment. Experimental Reactions were carried out in a carbon steel vessel (Figure 3) weighing 17,660 grams, having an internal volume of 140 ml., measuring 3.81 cm. in internal diameter, and 12 cm. long. I t was sealed with a rupture disk rated a t 940, 1525, or 4000 p.s.i., depending on the nature of the reaction, and provided with a thinwalled iron-constantan thermocouple and a tube 1.17 mm. in internal diameter to communicate pressure. Temperature was recorded and controlled by a Leeds & Northrup 115-volt, 30-cycleconverter recorder; pressure was recorded on a Leeds & Northrup recorder fed by an American Electronic pressure transmitter from Bourdon tubes of ranges 0 to 400 or 0 to 800 p.s.i. The vessel could be heated as necessary with a 1650-watt Glascol heater, the power to which could be controlled by a voltage regulator and the recorder controller. The assembly was mounted inside a sandbagged enclosure 5l/2 feet high, 52/3 feet wide, and 6 2 / / 3 feet deep, housed in a prefabricated steel shed. Sometimes butadiene of 96 to 98% purity from the butadiene extraction plant, inhibited with p-tert-butyl catechol, was used, the principal impurities being other C d hydrocarbons. More frequently, researchgrade butadiene, of average 99.5y0 purity and containing 0.02y0 p-tert-butyl catechol inhibitor (Phillips Petroleum Co., Bartlesville, Okla.) was employed. The inhibitor was removed before use by washing with aqueous caustic soda solution, by distillation alone, or (the preferred technique) by distilling over caustic pellets or Ascarite (75% sodium hydroxide on asbestos). Oxygen of minimum purity 99.4% was taken directly
from cylinders supplied by the Canadian Liquid Air Co. without further purification. * The reaction vessel was evacuated and chilled in a cold box at -10" F. Butadiene was added (usually 30 to 40 grams) from an aluminum transfer bomb, which was weighed before and after removal of butadiene. The reaction vessel was then installed in the enclosure and connected to the recorders. The temperature was adjusted by the Glascol heater to a figure slightly above that of the room to establish temperature control. Oxygen was forced in to a pressure predetermined by adjusting the control valve on the storage cylinder. After a short time for attainment of uniform temperature, the reaction vessel was isolated from the cylinder. If no change of pressure could be detected in 1 hour, the system was considered free of leaks. T h e temperature of the system was then raised to any required value. Progress of the reaction was followed by observing the pressure gage and chart. Usually, after the temperature was raised to provide the reaction conditions, the pressure rose to a maximum, and then fell to a temporarily constant value; these effects were considered to be due to oxy-
1 1
t RUPTURE
DISC
+.
Figure 3.
The test bomb had a capacity of 140 ml.
-e-
'/s-inch thermowell '/*-inch pressure well Bomb cavity 12 cm. in length, 3.81 cm. in internal diameter 0
VO1. 51, NO. 6
JUNE 1959
735
gen dissolving in the butadiene, overshooting of temperature, or both. After an induction period, the pressure decreased during the reaction period itself, until its value became constant. It never attained the theoretical minimum and some unreacted oxygen was found in the gas phase afterward, in almost all cases. Generally the temperature was then raised as rapidly as possible to induce the decomposition react ion.
Experimental Results
No signs of reaction or explosion have been observed when the pure butadiene was heated to its critical temperature of 308' F. or higher. Neither was any sign of explosion obtained by immediately heating butadiene with 3 to 4 weight oxygen added and before the oxygen had time to react with the diene. At temperatures below approximately 160" F., as observed by Rust ( 7 7 ) on a similar system, a reaction between oxygen and butadiene was observable, and was characterized by an induction period, followed by a fall of pressure. The combined induction and reaction periods range from 8.6 hours at 154' F. to 860 hoursat 80' F.. and both length of induction period and rate of reaction vary with temperature. If the temperature of the reaction vessel was raised rapidly, after oxygen absorption was completed, at a rate of about 2' to 3' F. per minute, to temperatures of 180' to 220' F.. an explosion usually occurred, particularly if the butadiene had previously absorbed more than 0.6 to 0.8 weight yooxygen. The explosions were violent and audible. Pieces of rupture disk were often driven into the wooden shield and structures around the reaction vessel. The remaining parts of the rupture disk were often flattened against the body of the reaction vessel and impressed with the scre\v threads of the fittings.
The undetached portions of the disk were sucked back into the reaction vessel, which suggests the passage of a detonation wave, when a closed 2-foot section of 2-inch pipe was screwed into the outer flange of the bomb to form a gastight expansion chamber of about four times the volume of the bomb. If the temperature was raised slowly, at rates less than 1' F. per minute, explosion often did not occur. I t was then decided to conduct the reaction between butadiene and oxygen in a glass vessel, to permit visual observations. A reactor vessel was constructed of borosilicate glass tubing 1 inch in diameter of 2.4-mm. wall thickness, joined to a ball and socket joint for connection to the oxygen line. When butadiene and oxygen were allowed to react at 140' F., the mixture first turned slightly yellow. After a period roughly corresponding to the induction periods previously mentioned, the mixture became cloudy and then deposited a heavy, sirupy liquid which formed a second layer below the liquid butadiene. Oxygen absorption appeared to be more rapid after the second phase appeared. This liquid product has been observed by Robey and others ( 9 )and Finigan ( 3 ) , and was studied by Kharasch ( 6 ) . Kharasch reported that the molecular weight, as determined by freezing point of solutions in benzene, indicated that it was a polymer containing equal numbers of butadiene and oxygen molecules with 7 to 9 units of butadiene. Handy and Rothrock (5)have recently confirmed this, reporting a predominantly 1. 4 addition product with lesser amounts of the 1, 2 type. This peroxidic material is nearly insoluble in butadiene and probably accounts for the second (heavy) liquid layer. It would appear, therefore. that explosions originate from the second phase formed by reaction between buta-
(IN
40-
1
'
I NOT RECORDEP,
h
I
20-
10-
'
I
I
700
500
300
P. S.I.G.
Figure 4. Temperature and pressure surges recorded when a 900-p.s.i. rupture disk remained intact show heat release was explosive
736
INDUSTRIAL AND ENGINEERING CHEMISTRY
diene and oxygen. I t is presumed that this phase contains peroxide groups in a concentrated and highly reactive form. Figure 4 is a diagrammatic reproduction of the temperature and pressure records obtained with the conventional recorders in a run in which the rupture disk was not shattered. In this experiment 19 grams of butadiene absorbed 0.97 gram of oxygen at 119" F. and was then heated to 203' F. A temperature surge of 600' F. was observed, which was too rapid for the recorder to follow in detail. The pressure recorder pen moved to the edge of the chart (700 p s i . ) and stuck until detached by tapping. It may be readily calculated that complete combustion of this amount of oxygen would liberate heat sufficient only to heat the reaction vessel and contents 1' or 2'. I t is obvious, therefore, that the heat release was of so short a duration as to be explosive. When the rupture disk is shattered, the temperature and pressure rise and fall are so rapid that no record is produced by conventional recorders. At this stage, it was decided to study the explosive reaction with a pressure recorder designed to respond over very short time intervals. +4specially designed strain gage packed with a soft silicone luting )vas connected to a tee in the oxygen line close to the entrance to the reaction vessel, and used to actuate a beam of light directed onto a high speed film recorder. Thirty grams of butadiene were passed, as vapor, through a tube containing Ascarite and condensed in a 100-ml. aluminum transfer bomb. This material was transferred to the reactor and alloived to react a t 140' F. with 0.9 gram of oxygen. If all the oxygen were converted to ( C ~ H ~ O Z ) , , 2.4 grams of such peroxide would form. The temperature was then raised at a rate of 2' to 3' F. per minute. Explosion occurred at 204' F. and produced pressure record 2 (Figure 5). A break in the curve occurs after 0.047 second at a pressure of 120 atm. After a further 0.224 second the pressure had reached 265 atm. (3810 p.s,i.),at which point the high pressure rupture disk failed. From previous calibration work it is estimated that pressures of 120 and 265 atm., in a 140-ml. vessel, would be obtained by explosion of 2.25 and 5.70grams of trinitrotoluene, respectively, assuming a normal flame temperature of 2000" K. The time intervals required for attainment of peak pressures with trinitrotoluene would be much less, and of the order of 0.5 to 0.6 ms. (0.0005 to 0.0006 second). A second experiment was carried out, with the same quantities of butadiene and oxygen. After approximately 7570 of the oxygen had reacted, the residual oxygen and butadiene was allowed to evaporate from rhe reaction vessel until the pressure was permanently reduced to 1 atrn. The maximum possible amount of butadiene
BUTADIENE EXPLOSIONS peroxide in the vessel in this experiment would therefore be 1.8 grams. The reaction vessel was closed and the temperature raised. Explosion occurred a t 175' F., giving the record 4 in Figure 5 . The pressure rose to 147 atm. (2120 p.s.i.) in 0.010 second and the heavy rupture disk held. I t is estimated that this pressure rise could be produced by explosions of 3 grams of trinitrotoluene, although the time intervals to peak pressure would be about 0.6 ms. as above. The actual amount of peroxides present a t the time of explosion would probably be of the order of half the maximum calculated amounts mentioned above, p y sibly because of partial decomposition during the heating period and the nonspecific nature of the oxidation. I t could be concluded that butadiene peroxide has the characteristics of a relatively slowburning explosive or a propellant, and can develop apparent peak pressures during explosion which would be obtained with two to four times its weight of dynamite or trinitrotoluene. Laidler (7) believes that this is only a shock wave phenomenon, however, and that equivalent pressures on a weight to weight basis are much more likely. There is some evidence from record 2 in Figure 5 , that the presence of excess butadiene may increase the force of explosion of butadiene peroxide in a closed vessel, although it is probably a simple volume effect. The composition of the gas mixture following a cool (expanded into a 2-foot, 2-inch pipe extension of the bomb cavity) and a hot (retained in the bomb cavity by a high pressure disk) decomposition is shown in Table I. I n both runs the experimental conditions were nearly duplicated and butadiene was removed from the bomb contents by vacuum pump a t room temperature before the thermally induced decomposition. The relatively
"
0.2
0.4
0.6
TIME
0.8
1.0
1.2
(SEC.)
Figure 5. High speed pressure records were made of peroxide decomposition in the Dresence of residual butadiene (No. 2) and when the butadiene had been removed (No. 4) large increase of methane and hydrogen and the large decrease in carbon dioxide in a hot reaction, as opposed to a cool one, probably demonstrates the role of temperature on the final distribution of gaseous reaction products. The analyses, made by gas chromatography, were responsible for the indefinite split on carbon dioxide and ethylene in the hot reaction. The solid residues were also strikingly different under these two types of experimental conditions. In the expansion-cooled reaction, the solid residues were black and sooty, with some oily components, and it was impossible to obtain a proper composite sample for analysis. The solid from the hot reaction was dry and fluffy with a bulk density of about 0.01 and an empirical formula of CIH. A small amount of hydrogen was generally noted in the vapor space after the reaction of oxygen with the butadiene was complete.
HlBlTFD
59RP.M. T.B.C.
Because the polymeric peroxide in concentrated form has the characteristics of an explosive, the remaining phases of the work were concerned with investigation of the effects of preventing its formation, decomposing it harmlessly after formation, and preventing its separation. Addition of small amounts of tert-butyl catechol to the reaction system prolong the induction period very markedly (Figure 6). If sufficient oxygen is present, once the inhibitor has been consumed the oxidation proceeds in a normal fashion and the reaction product still decomposes violently. It may be argued that destruction of the peroxide as it is formed probably prevents the formation of a second liquid layer in which the oxygen is soluble. This could account for the observed protraction of the induction period. Addition of aqueous caustic soda solution to the reaction vessel effectively de200 P.P.M. T.B.C.
1000 REM. TB.C.
\I
Table 1.
Gaseous Decomposition Reaction Products Run 121 Run 163 (Expansion (Hot Cooled) Reaction) 143 140 Reaction temp., OF. Depressured to p.s.i.g., before decomposition - 12 - 12 Special modifications Pipe exten- 4000-Ib. sion, 900rupture rupture disk disk Component
co
co2 Hz CH4 CzHd C3H6 C4Hs
Mole % ' 39.7 34.4
7.0 3.5 7.9 5.4 2.1
I
Mole % 40.6 2.0 max. 23.5 34.4
(Eluted with COS) 0.1 0.3
100
Figure 6. period
TIME ( H O U R S ) Small amounts of tert-butyl catechol markedly prolong the induction
P.P.M. (T.B.C.) = parts per million by weight, of p-ferf-butyl catechol. Weight butadiene charged = 35.9 grams; weight oxygen charged = 1.1 grams; temperature = 140° F.; initial pressure =
220 p.s.i.g. VOL. 5 1 , NO. 6
JUNE 1 9 5 9
737
Table II. Addition of Sodium Hydroxide Prevents Explosions (Oxygen, 3% by weight of butadiene charged; reaction temp., 140° F.; residual butadiene monomer and uncombined oxygen were vented before raising temperature at 2-3” F./minute) Temperature and Pressure Surges NaOH Temp. Max. Max. Butadiene Soln. NaOH surge temp. press. Charged, Charged, Concn., occurred, recorded, recorded, G. M1. Wt. % F. F. p.s.i. Run 155 35.7 nil 161 460 280 157
5 166 250 5 10 186 325 5 20 10 20 No temperature or pressure surges occurred in runs 160 and 159. 32.8 33.5 33.2 30.8
158 160 159
...
...
stroys the peroxide and also apparently completely prevents explosions, if it is present in excess (Table 11). This reagent has been used by Rust (7 7) to concentrate tertiary hydroperoxides and because it generally destroys primary and secondary peroxides, it probably prevents the formation of a peroxide layer. Water without the caustic soda does not prevent peroxidation and explosion on comparison runs. I t seemed likely that addition of other organic materials which would serve as solvents for butadiene peroxide might maintain the peroxide in a relatively harmless dilute form. This has been confirmed by the use of benzene or styrene. The addition of 0.2 mole fraction of styrene lowers the decomposition pressure surges under standard operating conditions from about 4000 to approximately 100 p s i . Butadiene itself may act as a poor solvent. By allowing unreacted butadiene to evaporate from the reaction vessel, the tempzrature required for explosion was reduced progressively from 178’ F. to as low as 144’ F. in the 140-ml. bomb. A violent decomposition at 120’ F. in a larger (1.5-liter) bomb, where presumably the wall effect was reduced, was noted during investigations after 6 to 7 weight 7 0 oxygen had been incrementally combined with butadiene a t that temperature. By storing reacted butadiene-oxygen mixtures a t various temperatures for varying periods of time before trying to actuate the decomposition thermally, it is possible to get an idea of the approximate storage times for active peroxide. This
Table 111. Approximate Storage Times for Active Butadiene Peroxide Storage Storage Temp., Time, O F. 185 150 140 115
Hours 1 7 10-12 70-100
“Active” butadiene peroxide is defined as that which showed temperature and/or pressure surges on heating.
738
O
.. 10
... ...
50 170
... ...
rough information is of considerable practical significance (Table 111). Observations of a sharp break in the growth rate of butadiene popcorn polymer a t about 80” F., indicate that the peroxide would be stable for extended periods at this and lower temperatures in systems free of activators (2). Styrene reaction rates with oxygen are about equivalent to, and isoprene reacts about ten times as fast as butadiene at 140’ F. in the small bomb. The rate of pressure and temperature rise from decomposition of these oxidized conjugates was much less than that for butadiene and couId be easily observed on standard Leeds & Northrup recorders. The drawoff point from drum C, for liquid butadiene, was at the bottom of the drum, 5 feet from the lower end; there was a 4-inch fall in 48 feet, and it has been calculated that about 1 gallon of a dense liquid could have accumulated at the bottom of the drum at the lower corner. I t seems likely that when a constant level was maintained in the drum, traces of oxygen accumulated in the stagnant vapor space and were gradually absorbed by the butadiene. This situation would be less likely to arise in a drum that was continually emptied and filled. The traces of peroxide formed would gradually polymerize and initiate popcorn polymerization of butadiene itself. The polymeric peroxide could have accumulated in the masses of popcorn polymer, settled to the lower surface of the drums, or been physically retained in pools by masses of the popcorn polymer. After a piece of popcorn, or a pool of peroxide, had grown beyond a certain size, the heat of polymerization would be difficult to dissipate, and the mass would become self-heating. Laboratory work has shown that a small rise of temperature, up to 140’ to 180’ F., would cause rapid decomposition of peroxide, and even lower temperatures of about 120” F. may be sufficient. As soon as the decomposition reaction sets in, the temperature could rapidly rise in a particular location to above the explosive limit for peroxide. Other peroxide in the drum could have then been exploded, by either shock or thermal means. I t is calcu-
INDUSTRIAL AND ENGINEERING CHEMISTRY
lated that only 10 to 50 pounds of butadiene peroxide decomposing over a reasonably short period of time was needed to destroy drum C. Precautions
The precautions now observed in the plant include the addition of 50 p.p.m. of tert-butyl catechol to butadiene leaving the rerun tower, and alternate emptying and filling of all butadiene storage vessels. The vapor spaces of storage spheres and drums are tested regularly a t least once a week. At locations showing appreciable amounts of oxygen, testing is more frequent, up to once per day. If the oxygen content of the vapor is greater than 0.5%, the vapor is vented until the oxygen content is reduced. Butadiene losses are prevented by recovering it from the vented gas by scrubbing with absorption oil containing 800 to 1000 p.p.m. of tert-butyl catechol. Acknowledgment
Several members of the Polymer Corp., in particular Charles Ambridge, C. M. Finigan, Walker Rideout, and M. S. Riley, participated in most of the experimental work. C. E. H. ‘Bawn, E. J. Buckler, K. J. Laidler, and C. A. Winkler contributed much helpful advice. Canadian Armament Research and Development Establishment, Valcartier, Quebec, provided equipment and assistance in making the decomposition rate measurements possible. Polymer Corp., Ltd., gave permission to publish this work. Literature Cited
(1) Chem. Eng. News 30, 1239 (1952). (2) Finigan, C. M., Polymer Corp., Internal Report, “Polymerization Studies on Butadiene-1,3,” PCLM-148 (Aug. 11, 1949). (3) Finigan, C. M., Zbid., PCLM-1011 (July 30, 1953). (4) Greenlee, K. W., Chem. Eng. News 26, 1985 (1948). (5) Handy, T. C., Rothrock, H. S., J . Am. Chem. Sac. 80, 5306 (1958). (6) Kharasch, M. S., private communication, 1952. (7) Laidler, K. J., private communication, Oct. 25, 1957. (8) Murphy, M. T., Duggan, A. C., J. Am. Chem. SOC.71, 3347 (1949). (9) Robey, R. F., Wiese, H. K., Morrell, C. E., IND.ENG.CHEM.36, 3 (1944). ( I O ) Rubber Reserve C o . , “Hazards of Butadiene and Acetylenes,” Dec. 1,
-.
1949
(11) Rust, F. F., J . Am. Chem. SOC.79, 4000 (1957). (12) Scott, D. A., Chem. Eng. News 18, 404 (1940). 113) Wentworth. R. L.. Industrial Liaison
. Officer, MIT, Cambridge, Mass., private
communication, Nov. 12, 1954, to V. Tucker, Lummus Co. (14) Winkler, C. A., private communication, May 1953. RECEIVED for review July 25, 1958 ACCEPTED February 5, 1959
