Berry, T., Cullis, C. F., Saeed, bI., Trimm, D. L., Advan. in Chem. Ser., 76, 86 (1968). Blundell, A., Skirrow, G., Proc. Roy. SOC.A , 244, 331 (1958). Bricker, C. E., Johnson, H. R., Anal. Chem., 17, 400 (1945). Cullis, C. F., Fish, A., Turner, D. W., Proc. Roy. SOC.A , 262, 318 (1961).
Cullis, C. F., Fish, A., Turner, D. W., ibid., 267, 433 (1962). Cullis, C. F., Fish, A., Saeed, M., Trimm, D. L., ibid., 289, 402 (19661. Di man; R. V., Fenske, RI. R., Jones, J. H., Prepr. Div. of Petrol. bhem., ACS, 15, (3) B-28 (1970). Fenske, RI. R., Jones, J. H., Daubert, T. E., J . Znst. Petrol., 52 (505), 1 (1966). Jones, J . H., Ernst, W. R., PTepr. Diu. of Petrol. Chem., ACS, 16 (3) B-5 (1971). Jones, J. H., Fenske, M. R., Znd. Eng. Chem., 51, 262 (1959).
Jones, J. H., Daubert, T. E., Fenske, M. R., Znd. Eng. Chem. Process Des. Develop., 8, 17 (1969a). Jones, J. H., Daubert, T. E., Fenske, 11.R., ibid., 196 (1969b). Mullen, J. D., Skirrow, G., Proc. Roy. SOC.A , 244, 312 (1958). Rust, F. F., Collamer, D. O., J . Amer. Chem. SOC.,76, 1055 llq.i4\ \-__-,.
Skirrow, G., Proe. Roy. Soc. A , 244, 345 (1958). Skirrow, G., Williams, A., ibid., 268, 537 (1962). Travlor. T. G.. J. Amer. Chem. SOC.. , 85., 2411 119631. RECEIVED for review July 9, 1970 ACCEPTED September 21, 1971 "
I
The authors express their appreciation to Esso Research and Engineering Co. for support of this work. Presented at the Division of Physical Chemistry, CIC-ACS Joint Conference, Toronto, Canada, May 1970.
Thermal Stability and Radiolysis of Some Methyl and Ethyl Polyphenyls and Hydrocracked Polyphenyl Mixtures Daniel A. Scolal and John S. Adams, Jr.2 Boston LaboratoriesJaMonsanto Research Corp., Everett, Mass. OW1@
By use of the high-pressure isoteniscope, thermal decomposition temperatures were determined for 4-ethylbiphenyl, 3-methyl-m-terphenyl, 3-ethyl-m-terphenyl, 4-methyl-p-terphenyl, 1,3-diphenyIcyclohexadiene- 1,3, m-terphenyl, Santowax-OMP (isomeric terphenyls), and high-molecular-weight polyphenyl mixtures (reclaimed polyphenyls and hydrocracked reclaimed polyphenyl mixtures). The pure compounds, except 3ethyl-m-terphenyl, were also irradiated with electrons at 400°C to a total dose of 7.2 X l o 9 rads, and the radiolytic gas and polymer yields were compared with m-terphenyl. Reclaimed polyphenyl mixture, hydrocracked partially hydrogenated polyphenyls, and Santowax-OMP were subjected to nuclear reactor irradiation a t 245°C to a total dose of 4.3 X 1 O9 rads, and the radiolytic gas and polymer yields of these were also determined. Electron irradiation of the alkylpolyphenyls resulted in lower radiolytic polymer yields but higher radiolytic gas yields than m-terphenyl. The pure alkylpolyphenyls and hydrocracked polyphenyl mixtures show lower thermal stabilities than either m- or p-terphenyl. Reactor irradiation of hydrocracked reclaimed polyphenyl mixture does not cause extensive polymerization of the mixture relative to the terphenyl mixture.
M i x t u r e s of 0-, m-, and p-terphenyls have found wide use as coolants and heat transfer liquids (Seymour, 1940). Because of excellent thermal and radiolytic stability (DeHalas, 1957 and Bolt and Carrol, 1956, 1963), the terphenyl isomer mixture has also been studied for use as coolaiit and coolant moderator in nuclear power plants (Charlesworth, 1961; Leny et al., 1962; Trilling, 1958). Experience in the operation of a n experimental organic moderated reactor (USAEC Report, 1960) has shown that a t reactor operating temperatures (325-375"C), thermal and radiolytic processes convert the terphenyl coolant t o higher molecular-weight polyphenyls and mixtures (PPM) (also called "high-boilers") . Present address, Research Laboratories, United ilircraft Corp., East Hartford, Conn. 06108. To whom correspondence should be addressed. Present address, Horizons Inc., Cleveland, Ohio. Present address, Dayton, Ohio 45407.
Low-molecular-weight materials such as methane, benzene, and toluene are formed t o a lesser extent. Catalytic hydrocracking was one method investigated for reconstituting PPRI to decrease coolant makeup costs. This method converts the high-molecular-weight pol3 phenyls t o a lower molecular-weight mixture with viscosity and vapor pressure similar to the terphenyl isomer mixture (Scola and Rineman, 1963; Scola and Kafesjian, 1963; Gardiier and Hutchinson, 1964). I n addition to terphenyl and quaterphenyls, this method produces about 20y0 alkylpolyphenyls, which consist mostly of methyl and ethyl derivatives (Scola and Kafesjiaii, 1963; Gardner and Hutchinson, 1964). Therefore, it seemed desirable t o determine t h e thermal and radiolytic resistance of ethyl biphenyl and methyl and ethyl terphenyl compounds, as well as hydrocracked PPlI mixtures for comparison with m-terphenyl and the isomenc terpheiiyls (SaiitowaxO U P ) . The thermal and radiation stabilities of several Ind. Eng. Chem. Prod. Res. Develop., Vol. 10, No.
4, 1971 417
Table 1. Properties of PPM Obtained from OMRE Operation.
Core I1 polyphenyl mixture Molecular wt, no. av C/H atomic ratio Melting range Terphenyl content, wt yo Viscosity a t 265"C, CP Thermal decomposition temp, "C Total exposure, M W days Appearance and state USAEC Report, 1960.
550 1.48 75-110°C 5 10.7 360 904 Black solid
Table II. Properties of Polyphenyl Mixtures RP
No. av mol wt 458 C/H atomic ratio 1.30 Viscosity a t 265OC, CP 4.2 Color and state Dark brown solid a
HCRP
PHP
HCPHP
306
518
295
1 30
1.14
1.12
1.3% Dark brown oil
8.0 Black solid
0.72 Greenbrown viscous oil
At 227'C. Table Ill. Thermal Stability of Some Polyphenyl and Polyphenyl Derivatives Thermala dec, temp O c
f looc,
Compound
Santowax-OMP m-Terphenyl p-Terphenyl 3-Methyl-m-terphenyl 4-Methyl-p-terpheiiyl 4-Ethylbiphenyl Hydrocracked reclaimed polypheiiylsb~c Hydrocracked reclaimed polyphenylsc 3-Eth yl-m-terphenyl Hydrocracked partially hydrogenated polyphenylsd Hydrocracked partially hydrogenated polyphenylsd Hydrocracked partially hydrogenated polyphenylsd
TD
490 485 478 466 457 451 426 416 416 393 393
388 388 Partially hydrogenated polyphenyle -370 Reclaimed polyphenyls 360 a The thermal decomposition temperature, TD,is defined as the temperature at which the decomposition rate is 1 mol 7,/hr (Johns et al., 1962). * See Materials section for the definition of the polyphenyl samples. Scola and Kafesjian, 1963; Scola and Adams, 1963a. Scola and Kafesjian, 1963; Scola and Adams, 1963b.
1,3-Diphenylcyclohexadiene-l,3
alkylpolyphenyl compounds have been reported previously (DeHalas, 1957; Bolt and Carroll, 1956, 1963; Carroll and Bolt, 1960). Materials
4-Ethylbiphenyl was synthesized (Huber et al., 1946), m p 33-4°C. By vapor-phase chromatography (6-ft, 15y0Apiezon 41 8 Ind. Eng. Chem. Prod. Res. Develop., Vol. 10, No. 4, 1971
L on chromosorb W a t 270°C, 60 psig helium), it was 99.5y0 pure. The synthesis of 3-methyl- and 3-ethyl-m-terphenyl was described previously (Scola e t al., 1963, 1970). Pertinent properties are as follows: 3-methyl-m-terphenyl, bp 169-7loC/0.25 mm, n * * ~ 1.5655, 98Y0 pure by vapor-phase chromatography (on above apparatus, retention time 10.5 min) ; 3-ethyl-m-terphenyl, bp 1677O0C/O.1 m m of 98y0 purity as determined by vapor-phase chromatography (retention time, 11.3 min) ; 4-methyl-pterphenyl, mp 209-10°C (recrystallized from benzene) (Scola et al., 1970; Gilman and Weipert, 1957); 1,3-diphenylcyclohexadiene-1,3, prepared by a published method (Scola et al., 1963; Woods, 1959), melted a t 97-9°C after recrystallization from ethanol. The PPAl resulting from nuclear degradation of terphenyl coolant used in the Organic Moderated Reactor Experiment (OMRE) (CSAEC Report, 1960) was obtained from Atomics International and designated Core I1 P P M (Table I). Solvent treatment of Core I1 P P M (Scola and Adams, 1963a) precipitates the high-molecular-weight portion and yields a soluble lower molecular-weight portion called reclaimed polyphenyls (RP). RP were subjected to catalytic hydrocracking to yield hydrocracked reclaimed polyphenyls (HCRP) (Scola and Kafesjian, 1963). Core I1 PPlI hydrogenated t o 16% hydrogen uptake and then subjected t o catalytic hydrocracking (Scola and Kafesjian, 1963; Scola and Adams, 1963b) was called hydrocracked partially hydrogenated polyphenyls (HCPHP) . m-Terphenyl was purified by distillation folloaed by fractional freezing to a purity of greater than 99% (Yanko and Ellard, 1963). Santowax-OMP from the hlonsanto Co. consisted of biphenyl 0.5010, o-terphenyl 11.7%, m-terphenyl 59.6%, and p terphenyl 26.7%. Properties of reclaimed polyphenyl (RP), hydrocracked reclaimed polyphenyl (HCRP), partially hydrogenated polyphenyl (PHP) , and hydrocracked partially hydrogenated polyphenyl (HCPHP) are shown in Table 11. Experimental
Thermal stability determinations were made on 1-gram samples with a high pressure isoteniscope, method D, described previously (Johns et al., 1962). The method is not intended t o rate coolant life but only thermal stability relative t o terphenyls. Electron irradiations were made on 5to 10-gram samples with a 2-MeV van der Graaff electron accelerator and radiolyzed t o a total dose of 20 W-hr/g a t 400°C (7.2 x 104 rads). Weight percent gas produced during the irradiation was determined by the difference in sample weight before and after irradiation. Weight percent volatiles were obtained b y measuring the weight loss after treatment of the irradiated sample for 2 h r at 200'C at atmospheric pressure. Polymer yields were obtained with a precision of &5y0b y measuring the polymer remaining after microdistillation of a 1-gram irradiated sample for 4 hr at 20OoC/0.5 mm (Scola et al., 1963). Number average moleculai weight of the samples was determined by a cryoscopic technique with a published procedure (Campbell et al., 1963). Percent gas and polymer yields resulting from the m-terphenyl and the 0 - , m-, and p-terphenyl mixture (SantowaxOLIP) irradiations were taken as unity. Relative gas yield is defined as the ratio of the average percent of gas produced on irradiation of the sample t o t h a t percent produced on irradiation of m-terphenyl. The same definition applies to the relative polymer yield. Gas or polymer yields obtained from the reactor irradiated samples were compared with the yields obtained from Santom-ax-OLIP.
Radiolytic Stability of Some Polyphenyl and Polyphenyl Derivatives at 400°C.
Table IV.
(2 MeV electrons, 7.2
Gasd
Compound
x
109 rads)
Decomposition, wt %* Volatiled Polymerd
Totala
Relotive yields,c average values Gas Polymer
21.3 0.30 20.2 1.00 1.00 0.76 18.8 4.31 0.76 0.13 15.4 3.28 12.9 0.85 10.4 2.75 0.53 1.65 14.6 0.66 11.4 2.53 12.7 4-Methyl-p-terphenyl 1.25 0.54 0.13 11.7 0.92 11.7 0.97 0.10 10.7 17.6 5.68 0.48 1,3-Diphenylcyclohexadiene-l,3 4.92 4.05 8.64 16.9 3.71 2.49 10.8 a A 2-MeV van der Graaff electron accelerator was used. b Duplicate runs are given for all except 4-ethylbiphenyl and m-terphenyl. d These values represent the gas, volatile, and polymer produced during the irradiation. See Exe See Experimental for definition. perimental for definitions. These values are the sum of the gas, volatile, and polymer values. m-Terphenyl 4-Ethylbiphenyl 3-Meth y l-m-terphenyl
6
Table V.
Run no.
Radiolytic Stability of Hydrocracked Reclaimed Polyphenyls and Hydrocracked Partially Hydrogenated Polyphenyl Mixtures
Sample
Before irradiationa PoIy mer No. av,b yield, mol wt wt %c
After irradiationa Polymer No. av, yield, mol wt wt %
Relotive polymer yieldC
Relotive gas yieldC
1 la Ib 2 2a 2b
HCRPd 288 48.7 320 71,l 0.95 2.5 HCRPe ... 11.4 ... 32.5 0.89 0.38 HCRPe ... 11.4 ... 40.4 1.27 1.65 HCRP 243 36.9 288 57 0.85 4.6 ... 7.8 ... 27.9 0.94 0.90 HCRPe HCRPe ... 7.8 ,.. 27.9 0.94 0.69 3 HCRP 263 37.1 343 70 1.40 7.71 ... 5.7 ... 24.9 0.81 0.96 3a HCPHPd 3b HCPHPe ... 5.7 ... 23.2 0.74 0.79 4 HCPHP 254 37.1 245 93.3 2.37 8.7 ... 5.5 ... 25.3 0.84 ... 4a HCPHPe 4b HCPHPe , . . . 5.5 ... 23.8 0.77 4.1 5a HCPHPe ... 14.6 31.5 0.72 0.85 5b HCPHPe ... 14.6 ... 31.5 0.72 0.55 0 252 23.6 1.00 1.00 6 Santowax-OMP 230 a Irradiated in the Materials Testing Reactor, Idaho, temp 245OC f 10°C, dose 4.3 X 109 rads f 1 X 109 rads. See Experimental (Campbell et al., 1963). See Experimental (Scola et al., 1963). See Materials section for definition of the polyphenyl samples. e 30 wt 7c in Santowax-OMP. f Unmeasured high dose. .
Hydrocracked polyphenyl samples were radiolyzed in the Materials Testing Reactor, Hole HM-5, shuttle tube (located a t t h e National Reactor Testing Station in Idaho) t o a total dose of 4.3 X lo9 rads at 245OC. Samples (17-25 grams) were degassed before irradiation. Results
Table I11 lists the thermal decomposition temperatures of the polyphenyl derivatives. The results show that a methyl group lowers the thermal decomposition temperature of mor p-terphenyl by about 25OC, while the ethyl group in mterphenyl causes a much larger decrease in the thermal decomposition temperature of m-terphenyl (about 70°C). These results are similar t o the effect of the methyl and ethyl group on biphenyl (DeHalas, 1967; Bolt and Carroll, 1956, 1963). The thermal decomposition temperature of hydrocracked reclaimed polyphenyl mixtures falls in the same general temperature area (415°C) as 3-ethyl-m-terphenyl while hydrocracked partially hydrogenated polyphenyl mixture and the other polyphenyl mixtures shown (Table 111) have thermal decomposition temperatures similar to 1,3-diphenylcyclohexadiene-lJ3. Kuclear magnetic resonance studies of hydrocracked reclaimed polyphenyls indicate
.
I
the presence of aliphatic groups, which are mostly methyl or ethyl groups (Scola and Kafesjian, 1963; Scola et al., 1963). The concentration of alkylpolyphenyls is estimated a t 20% by nmr and VPC (Scola and Kafesjian, 1963; Bolt and Carroll, 1956, 1963). Table IV gives the data for t'he electron irradiation of the polyphenyl derivatives except for 3-ethyl-m-terphenyl. m-Terphenyl was also irradiated and used as the standard for comparison. The results show t'hat a methyl substituent increases the electron radiation resistance of the m-terphenyl or p-terphenyl molecule, thereby decreasing the polymer yield relative t o m-terphenyl. Partially hydrogenated berphenyl, 1,3-diphenylcyclohexadiene-1,3, shows similar radiation stability. Even though the relative gas yield of these polyphenyl derivatives is greater as is expected for a system containing alkyl groups, the total yield of decomposition products is less than m-terphenyl in all cases. Greater resistance of the methyl terphenyl and cyclohexadiene derivative to form polymers in a n electron radiation environment may be owing to the stabilizing influence of benzylic type free radicals formed during radiation of the compounds (Schoepfle and Fellows, 1931; Freeman, 1960; Sweeney et al., 1967). Results of nuclear reactor irradiation of hydrocracked Ind. Eng. Chem. Prod. Res. Develop., Vol. 10, No.
4, 1971 419
polyphenyl samples and 30 wt % solutions of hydrocracked polyphenyl samples in Santowax-OJIP are shown in Table V. I n every case hydrocracked polyphenyl samples gave polymer yields which do not vary greatly from t h a t of SantowaxOMP (except run 4), considering t h a t the accuracy of the measured dose varies by +25%. This is significant since these samples contained approximately 20 wt yG alkylpolyphenyl (mostly methyl and ethyl derivatives). Other workers have also shown t h a t slightly lower radiolytic polymer yields are obtained from reclaimed hydrocracked polyphenyl coolant samples which also contained alkylated compouiids than from those of Santowax-OhlP (Gardner and Hutchinson, 1964). The results suggest t h a t reconstituted hydrocracked polyphenyl coolant containing methyl or ethyl substituents may have possible use as a heat transfer medium in a radiation environment. Acknowledgment
The authors are indebted t o William H. Yanko and Mark Gutzke, Monsanto Research Corp., Dayton Laboratory, Dayton, Ohio, for performing the electron irradiations. The nuclear irradiations were performed by California Research Corp., Richmond, Calif., under the supervision of R. 0. Bolt. literature Cited
Bolt, R. R.,Carroll, J. G., Proc., “International Conference on Peaceful Uses of Atomic Energy,” Geneva, 7, ,546 (1936), also text “Radiation Effects on Organic Materials,” Academic Press, New York, N.Y., 1963. Campbell, R. H., Bekebrede, A. E., Gudzinowicz, B. J., Anal. Chem., 35 ( l a ) , 1989 (1963). Carroll, J. G., Bolt, R. O., Sucleonzcs, 18 (9), 78 (1960). Charlesworth, D . H., “Status of Fouling Experience in OrganicCooled Systems at A.E.C.L.,” CEI-132, May 1961. DeHalas, D. R., “Pyrolytic and Radiolytic Decomposition of Organic Reactor Coolant,” USAEC Rept. TID-4500, 13th ed. rev., Nov. 25, 1957. Freeman, G. R., J . Chem. Physzcs, 33 ( l ) ,71 (July 1960). Gardner, L. E., Hutchinson, W. U., Znd. Eng. Chem. Prod. Res. Develop., 3 (1) 28 (1964).
Gilman. H.. Weioert. E. A.. J . Ora. Chem.. 22. 446 (1957). Huber,’F. h’., Renoll, AI.: Ross”ow, A. G., ’Mowiy, D’. T., J . Amer. Chem. SOC.,6 8 , 1109 (1946). Johns, I. B., RIcElhill, E. A,, Smith, J. O., J . Chem. Eng. Data, 7 (2), 277 (1962). Leny, J. C., Orlowski, S., Charrault, J. C., Lafontaine, “Orgel, A European Power Factor Design,” European Atomic Energy Community, Euratom, Eur., 85e (1962). Schoepfle, C. S., Fellows, C. A., Znd. Eng. Chem., 23 (12), 1396 11931). Scola, D.A., Adams, J. S., “Reckmation of Nuclear Reactor Coolant by Solvent Treatment, USAEC Rept. IDO-11057, Aug. 22, 1963a. Scola, D. il., Adams, J. S., “Studies of the Reclamation of Organic Nuclear Reactor Coolant by Partial Hydrogenation of Polyphenyls,” USAEC Rept. IDO-11058, May 15, 1963b. Scola, D. A., Adams, J. S., Bekebrede, A. E., Znd. Eng. Chem. Prod. Res. Develon.. 9 13). 413-19 (1970). Scola. D. A,. Adams. J.”S.. Richiusa. ’C. C.. Kafesiian. R.. “Fburth Annual Report, Organic Coolant Reclamatio; and Coolant Chemistry,” USAEC Rept. IDO-11055, May 10, 1 qfi.?
-I--.
Scola, D. A,, Kafesjian, R., “Catalytic Hydrocracking of Polyphenyl Systems for Use in Reclamation of Organic Nuclear Reactor Coolant,” USAEC Rept. IDO-11056, June 30, 1963. Scola, D. A., Wineman, R. J., Znd. Eng. Chem. Prod. Res. Develop., 2 . 3 2 2 (1963). Seymour, H., Chem. Age (London) 43,43 (1940). Sweeney, AI. A., Hall, L. H., Bolt, R. O., J . Phys. Chem., 71 (6), 1564-71 (1967). Trilling, C. A., “The OMRE-A Test of the Organic ModeratorCoolant Concept,” Proc. Second United Nations International Conference on Peaceful Uses of Atomic Energy, Geneva (Sept. 1958) Geneva, United Nations, 1958, 1‘01 9, pp 421, 468. USAEC Rept. K;AA-SIi-5688, Organic Coolant Reactor Forum, Proc. (Oct. 6-7, 1960). Woods, G. F., “Preparation and Properties of Some Polyphenyls,” WADC Tli 39-496, p 93 (Sept. 1959). Yanko, W. H., Ellard, J. A,, “Thermodynamic Properties of BiDhenvl and the Isomeric Terohenvls.” USAEC Reot. IDOllb08 (“Oct.31, 1963). I
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RECEIVED for review July 20, 1970 ACCEPTED June 29, 1971 This work was supported by the United States Atomic Energy Commission under contract AT(10-1)-1088.
Production of Carbon Black from Assam Coal R. Haque,l
R. K. Chakrabarti, M. 1. Dutta, and M. S.
lyengar
Regional Research Laboratory, Jorhat, Assam, India
The direct conversion of the high-volatile vitrain-rich coals of Assam to thermal-type carbon black was investigated. The reaction takes place in a high-temperature transport reactor in which heat i s supplied by partial combustion of the coal feed a t high volumetric production rates. Factors, such as air-to-coal ratio, feed rate, reaction temperature, and the nature of coal and its mineral matter, determine the yield and quality of carbon black, The product is compared with that obtained b y conventional methods. Data o n compounding of the carbon black in rubber mixes are given.
C a r b o n black is mainly produced by the cracking of natural gas, petroleum hydrocarbon, and coal t a r oils. Prior t o 1950, 95% of the world’s supply of carbon black was based on using natural gas as ram material, and 75yG of the world’s supply came from the CSh. Today, however, the major amount of carbon black is produced by the oil furnace process which allows location of the unit near the consumer. To whom correspondence should be addressed. 420 Ind. Eng. Chern. Prod.
Res. Develop., Vol. 10, No.
4, 1971
The first production of carbon black from coal was reported by Johnson et al. (1967a,b). Coal crushed through 325 mesh was dropped in a free fall through a temperature zone of 125OOC in the presence of air, ammonia, nitrogen, or argon to produce a black costing about $0.03-0.04/lb. The same workers, in producing hydrogen cyanide from highvolatile coal and ammonia, reported that about 6-107, of the coal was converted to carbon black. The process was carried out a t 125OOC and produced fine thermal-grade
