wing Carcinogenicity of High Boiling Petroleum Products L. T. EBY
AND
JOHN REHNER, JR.
Esso Laboratories, Standard Oil Development Co., Linden, N. J .
MARVIN KUSCHNER
WILLIAM E. SMITH
AND
Department of Industrial Medicine, Post-graduate Medical School, New York University, New York, N . Y .
A
The numerical values of tumor potency used for the quantitative expression of carcinogenicity are defined in a companion paper ( 8 ) .
RECENT publication (6) from these laboratories has disclosed that disposal of catalytic cycle stocks, clarified oils, and related high boiling carcinogenic products from modern catalytic refining operations can be accomplished economically by recycle catalytic cracking or thermal cracking to reduce production of catalytic products boiling above 700’ F., or by blending to a safe tolerance level with noncarcinogenic refinery streams. The term “carcinogenic” as used in this paper applies to those materials that produce a significant tumor and/or cancer response when repeatedly applied to the skin of mice under specified testing conditions (IS). Alternate methods for reducing the Carcinogenicity of such products were also studied, because the earlier literature on some of these methods is based almost exclusively on shale oil and coal tar fractions. The preliminary results merit publication a t this time, even though they have not been extensively tested on a refinery scale, because:
OXIDATION
One of the most attractive methods for reducing carcinogenicity may be simple air oxidation a t somewhat elevated temperatures. I t has been known for some years (15) that oxygenation of shale oil and pinene synthetic tar a t temperatures of about 150’ C. can greatly reduce their carcinogenicity. Recently, irradiation and aeration of high temperature shale tar were shown to have a similar effect (4). No further study appears to have been made to elucidate the mechanism of deactivation. The carcinogenicity of certain pure polynuclear aromatic hydrocarbons can be reduced by ultraviolet irradiation ( 8 ) . This may be due t o dimerization (12) or photooxidation ( 5 ) . Furthermore, (9) the oxidation of 9,10-dimethyl-l,2benzanthracene with sodium dichromate destroys its activity. I n the first experiments a >700° F. fraction of a heavy catalytic oil (sample No. 344) was blown with air for 7.5 hours a t 200” C. Animal tests showed that the tumor potency was reduced from 61 to 31 by this treatment. The quantitative significance of this reduction is uncertain since loss of animals from intercurrent causes was greater in the latter test. Table I shows inspection data of the original and oxidized oil. Some further indications of the nature of the changes produced by this treatment were revealed in the subsequent work, in which
1. Some of these alternate methods show promise for industrial application to some modern refinery products. 2. Such methods may be needed for the disposal of carcinogenic products if spare catalytic cracking capacity is not available, or if blending cannot be employed. 3. The methods may be more broadly applicable to related types of carcinogenic products derived from shale oil or coal tar. blthough some of the methods appear to be effective and practical, the present results are regarded as preliminary for, aside from possible economic limitations, they cannot be recommended without qualification until they have been widely tested with the large variety of high boiling products normally encountered in modern refining operations.
300.C. 275%. I - -
u W
CIS
-
t-w z
-
a w
c 0
6
”
100.C.
8
1
TIME OF AIR BLOWING, HOURS
0
Figure 1. Oxygen Content of Air Blown Catalytic Oil
Figure 2. A
2209
2 4 TIME OF A I R BLOWING, HOURS
6
~.
6
Oxy Content of Air Blown Catalytic Oil
INDUSTRIAL AND ENGINEERING CHEMISTRY
2210
Vol. 46, No. 10
potency in both cases, the degree of reduction depending on the amount of ozone employed. HYDROGEN ATIBh 250%. 279%.
L
W
L
d
\\
,,3OO'C.
Polynuclear aromatic hydrocarbon components appear to be mainly if not entirely responsible for the carcinogenicity of high boiling catalytically cracked stocks (6). Hydrogenation would therefore be expected to reduce the carcinogenicity of such stocks since hydrogenation, if carried far enough, usually reduces or destroys the potency of carcinogenic polynuclear hydrocarbons (1, 3). I n a preliminary laboratory experiment, a heavy catalytic oil (eample KO. 191) WRS hydrogenated to take up about 1 mole of hydrogen per mole of oil, using a commeicial nickel tungsten sulfide catalyst a t 2500 pounds per square inch for 15 hours at 250' C. The biological tumor potency of the oil
AROMATICS
2 4 TIME OF A I R B L O W I N G ,
6
HOURS
Figure 3. Aromatics and Nonaromatics Content of Air Blown Catalytic Oil
the time and temperature of oxidation of the same oil were varied, and inspection data were obtained on the products. In these esperimenk 500 grams of the sample were blown a t the rate of 500 ml. of air per minute in glass equipment. The results are summarized in Figures 1 to 4. I n each case oxygen became chemically combined with the oil. Comparison of Figures 1 and 2 shows that t,he amount of combined oxygen parallels the amount' of "oxyJ' fraction ( 7 j formed. The rate of oxida,t,ion is negligible at 100" C. but increases rapidly with increasing temperature. Figure 3 shows that below 300" C. the oxidation takes place largely with the aromatic components, and the nonaromatics are scarcely attacked. Asphaltene forniation is attributed commonly to dehydrogenation and the formation of high molecular weight derivatives. If this is correct, then Figure 4 shows that the dehydrogenation process does not become rapid until temperatures of about 300" C. are reached. This view is supported by the observation that the amount of water recovered from the gas effluent from the reaction roughly paralleled the amount of asphalt'enes formed. The results therefore indicate that reduction of carcinogenic potency of a petroleum oil resulting from air oxidation, under the above conditions, is due to chemical combinat,ion of oxygen with reactive aromatics rat,her than to asphaltenes formation. I n order to effect a sizable reduction in potency with a minimum consumption of nonaromntics and aromatics, reaction teniperature should be maintained below 300" C. Since the course of oxidation depends on the conditions employed, the reduction in carcinogenicity may also depend on these conditions, a,nd on the type of oil or tar that is oxidized.
oo----
2
8
6
Figure 4. Asphaltenes Content of Air Blown Catalytic Oil
TABLEI.
OXIDATION O F CATALYTIC O I L ( 8 4 Y P L E NO.344) Original Catalstio Oil
Yield of residue, mt. Yo Properties of residue Oxygen, 56 Asphaltenes. 7F Nonaromatics, %" of nonaroinatics Aromatics, %'O" n": of aromatics Oxy fraction, yo" Biological tumor potency
* Obtained
TABLE 11.
100
0.52 0.5 81.4 1.4473 38.9
1,6512 3 9
61
Air Blown a t 200O C., HII 2.5 L O 7.5 98.05 95,15 07.04 1.06
1 19
. I .
.., , . .
fi3.1
.
I
.
,
.
.
I
.
I
.
0.9 .
.
I
. . I
...
0.5
.,
1 4476 24.0 l.ii400
... . .,
- -
...
1
...
J
31
by high aromatics characterization procedure : 8 )
Roonf TEXPERATURE O F T A R FROM STEAMCRACKING
OZONIZATION A T
0 ZOVI ZATIOS
A tar from steam cracking v a s treated at room temperature for 13.6 and 68 hours with ozonized oxygen containing 0.049 gram of ozone per liter. Control runs xere made with oxygen under the same conditions. The potency of the tar K R S not reduced in the control runs but was substantially reduced by the ozone treatment, as shown in Table 11. There was reduction in
4
TIME OF AIR B L O W I N G , HOURS
Length of TreaLment, Hr.
Gas
Ozone Absorbed,
m.t %
Biological Tumor Potency
October 1954
2211
INDUSTRIAL AND ENGINEERING CHEMISTRY TABLE111. HYDROUENATION AND CATALYTIC RECRACKINQ OF CATALYTIC OILS
A
B C
D E
F
G H
I
J
K L M N 0 a
b 6
Sample Description Heavy virgin gas oil Catalytic oila Catalytic oilb Hydrogenated B Hydrogenated C Hydrogenated C Hydrogenated C Hydrogenated C Cracked B Cracked C Cracked D Cracked E Cracked F Cracked G Cracked H
Hydrogenation Conditions Ha M ~ ~ pressure , vel, % absorbed, temp , Ib /sq. of cu. ft./bbl. F. inch >700° F.
.. 350 350 450 800 1050
..
750 710 554 650 700
.. ..
84 78
67
750
55
750 3000 3000 3000
53 59 51 4R . . 26 27 20 30 30
..
Biological Tumor Potency Gravity Whole >700° F. OAPI oil fraction 26.4 22.2 21.6 24.6 23.7 23.9 26.4 28.2 11.4C 9.9,"
17 91 , .
55 80
..
33 103 io2 110
12: 5 C 15.9C 20.1e .. 26 23.7O T h e >650° F. fraction (less 5 % bottoms) from commercial cracking of sample A. A Ride cut clarified oil (less 3 % bottoms) from commercial cracking. Gravity of >700° F fraction.
was reduced from 55 to 45 by the treatment. This result indicated that, in order to effect a large reduction in potency, the hydrogen consumption should be increased. This variable, and also the effect of recracking the hydrogenated material, were explored with a series of samples obtained from plant hydrogenation studies. I n these, the same hydrogenation catalyst was employed; the conditions are shown in Table 111. The data in TabIe I11 show that the tumor potency of the whole oil is reduced with increased hydrogen consumption. The latter is reflected in the recorded gravity values for the hydrogenated stocks. I n order to effect a large reduction in potency, the hydrogen consumption should be of the order of 2 to 3 moles per mole of oil (700 to 1000 cubic feet per barrel). This ratio might be reduced if the original material has a lower potency to start with. For example, a separate experiment showed that a 600' to 740" F. fraction of hydrogenated tar (from the thermal cracking of a catalytic oil) containing 1.1 mole of absorbed hydrogen per mole of tar was inactive; the corresponding fraction before hydrogenation had a potency value of about 30. The yields of > 700' F. material shown in Table I11 from the catalytic recracking of the hydrogenated stocks were about the same as those for the unhydrogenated stocks. Likewise, the tumor potencies of the > i O O " I;. fractions were about the same. This indicates that, on recracking the hydrogenated stocks, carcinogenic components are formed again in amounts equivalent to those obtained on cracking the catalytic oil without intermediate hydrogenation. In other words, the direct hydrogenation of a carcinogenic oil can be advabntageous in reducing its potency, but on the other hand, little or nothing is gained, from the standpoint of reducing over-all carcinogenicity, if the hydrogenated stocks are to be recracked.
..
..
IO1
25
of diisobutylene was added to the reaction mixture. After removal of catalyst and excess diisobutylene, the product was biologically tested. Table IV shows that treatment with aluminum chloride alone produced appreciable change in chemical romposition, but without significant reduction in tumor potency. On the other hand, alkylation with diisobutylene resulted in a marked decrease in potency in the single test conducted. It will also be noted that, in contrast to the other methods described in this paper, alkylation has no appreciable effect on the concentration of aromatic hydrocarbons, nor does its beneficial effect depend on their destruction. Thus, the physical properties of the oil suffer little change by this method of deactivation.
TABLE IV.
ALKYLATION
Reagents None (control) ~ 1 ~ 1 ~ AlCh diisobutylene
+
5
WC, Atomic Ratio 1.667 1.674 1,721
OF
CATALYTIC OIL (SAMPLE KO. 344) Caffeine Numbera 0.561 0.455 0.265
Aromatics ~ ~ ~ -~Biological t i Tumor % n2; Potency 33.9 1.6512 61 32.4 1 6369 59 32.8 1.6345 35
Determined by published procedures (8)
TABLE V.
Adsorbent None (control) Magnesol NoriteA
CONTACTING CATALYTIC OIL (SAMPLE No. 191) WITH SOLIDADSORBENTS Optical Absorptivity a t 420 430 440 500 mp m p mp mp 0 . 3 4 6 0 . 2 5 6 0.219 0 090 0.067 0.072 0:111 0.079 0.065
0,048 0.007 0,013
Aromatics FractionO
____ %
n'~?
32.2
1.6316
28:4
1.6211
....
Biological Tumor Potency 54 39 13
Determined by high aromatics procedure (8).
A LKY LATIOh
Many alkyl derivatives of carcinogenic polynuclear aromatic hydrocarbons have been synthesized and studied. An inrrease in the length of the alkyl chain results in reduced carcinogenicity ( I ) , whereas very small groups, such as methyl or ethyl, often enhance the potency. This suggests that alkylation of carcinogenic oils with higher olefins should be beneficial in reducing tumor potency. This was confirmed by laboratory experiments. The catalytic oil referred to in Table I (sample No. 344) was treated with 8.25% aluminum chloride for 2.5 hours a t 100' C. to determine whether internal alkylation or isomerization would be effective in reducing carcinogenicity. After removal of residual catalyet, the final product was compared with the starting material in mouse tests, Another experiment was carried out under identical conditions except that 40 weight per cent
ADSORPTION
Preliminary data on samples prepared in these laboratories have shown that treatment of potent oils with active adsorbents reduces carcinogenicity (15). Several methods of using adsorbents have been employed for removal of aromatics from catalytic oils. With large ratios of selective adsorbents and solvents to oil, complete separation of aromatics may be achieved and the nonaromatic raffinate is completely inert, Although this procedure is not commercially practical, treatment with smaller ratios of adsorbents in the absence of a solvent medium, such as commercial clay treating of oils, is within the scope of consideration. Adsorption studies show that this can be done with properly selected adsorbents, and they also throw light on the chemical nature of the process.
~
~
a
INDUSTRIAL AND ENGINEERING CHEMISTRY
2212
TABLE VI. I I1 I11 IV
1'
VI VI I VI11 IX
SEPARATIOX Of
>'iooo F. AkROUATICS FROM CATALYTIC
I1
0.126 1.4575 B
0,093 1.4763 B
0.576 1,4777 B
0 164
B, K
0.056 1.4650 B
0.120 1.4810 B
1.106 1,5005
2,586
n 6:
Aromatic types
B,
1.6462 p , PY 0.461 1.6960 365. 386, 407, 437
n5:
Aromatic types Blumina U't. of fraction, grams n 5: Aromatic types Nuchar C Wt. of fraction, grams n5$ Aromatic types Magnesol Kt of fraction, grams
Fuller's earth Wt. of fraction, grams Aromatic tyues
B = Benzenes N = Kaphthalenes P = Phenanthrenes P y = Pyrenes L = Low in .4romatics Figures = Long wave-length peaks (mp) in mixtures .4romatic types identified from ultraviolet absorption curves of fractions
++ ++ ++
I
n:5
OIL WITH SOLID -4DsORBENTS Aromatic Types
Solvents n-Heptane 1% Benzene 9 9 % n-heptane 2 % Benzene 98% n-heptane 4'3 Benzene 96% n-heptane 10% Benzene 90% n-heptane 20Yo Benzene 80% n-heptane 50% Benzene 50% n-heptane Benzene Pyridine
Solvent Silica Gel Wt. of fraction, grams
s
4.175 1.6083 B, N , P,P y
Vol. 46, No. 10
1,5148
I11
IV
v
0.099
n
1.4768
0 503 1.4959 B, h-
0 459 1,5545 N, P
2 081 I . 6496 p, P Y
1 438 0 108 1.6585 Dark 366,336,436 ?
0.283 1.5440
0.230 1.5667
1.019
s
0,884 1.6443
N
0.618 1,6153 N, P
0.129 1.4862 B
0.123 1.4904 B, N
0.149 1,4955 B, S
YI
VI1
P
1.6682 p , PY
0,097 1.5102
0.211 1,5342
0,267 0.514 1.5425 1.5G60 N N
N
0.453 0.226 0.148 1.6580 1.6874 1.71P,P y , 430 343, 365, 383, 346, 365. 387, 407, 437 408, 439
0.090 Dark 346. 367, 387, 406,430. 440
0.131 Dark ?
0.083 Dark ?
0,054 Dark 438
0,033 Dark 450
0.041 Dark ?
0.153 Dark ?
Data were previously presented ( 1 6 ) showing the effect of a single treatment of a catalytic oil (sample KO,191) with 10% by weight of a variety of solid adsorbents on the optical absorptivities. These data provide an early indication that the nature of the adsorbed components depends on the particular adsorbent chosen. Similar treatments of the same catalytic oil werc carried out with 2070 of Magnesol and with 20% of Korite A. Table V shows some properties and the corresponding tumor potencies of the original and treated products. Both adsorbents reduced tumor potency; the Norite A seems more effective. This occurred despite the fact that hlagnesol n a s the more effective decolorizing agent, as shovn by the optical absorptivity data. The latter in conjunction with the small change in aromatics content suggests a selective action of activated carbon for this purpose. Adsorption studies were then carried out with the >700° F. aromatics fraction from this oil in order t o explain the action of various adsorbents, including activated carbon. A 5-gram sample dissolved in n-heptane was deposited on the adsorption column containing 600 ml. of adsorbent according t o the procedure described elsewhere ( 7 ) , and was eluted in turn with 800-ml. portions of the series of solvents and soIvent mixtures given in Table VI. The fractions obtained by evaporation of the eluates were characterized by weight, refractive index, and aromatic types as determined by ultraviolet spectra. The activated carbon, Nuchar C, is exceptional in the tenacity with which it retains the polycyclic hydrocarbons above naphthalene. This could account for the apparent ability of activated carbons to reduce carcinogenicity in contrast t o Magnesol which, according t o Table VI, releases the higher aromatic types more readily. Xone of the other adsorbents studied retained the higher polycyclic hydrocarbons as well as did Nuchar C. On this basis it would be expected that they would not be a s effective for biological deactivation by a single contacting procedure. ADDITIVES
Crabtree ( 8 ) hae shown that the onset of tumor formation in mice subjected t o skin painting with carcinogens, such as 3,4benzpyrene, 20-methylcholanthrene, and 1,2,5,6-dibenzanthracene can be inhibited by intermittent painting with solutions of
0.033 Dark 450
0 150 Dark ?
0.724 0.358 1.6580 Dark 436 336.385. 440
s
0,033 Dark 441
IX
VI11
0.458
Dark
L 0.208 Dark
L
certain dithiols, one of lvhich is 2,3-dimercaptopropanol (B.4L). (The Ring Index name of these three compounds are benzo[a]pyrene, 3-methvlcholanthrene, diben7 [a,h]anthrarene. ) IXrect incorporation of thP inhibitors into the carcinogen solutions apparently m s not attempted, nor did the investigation embrace substances other than thiol compounds. Other authors ( I O , 11, 24) have demonstrated that the carcinogenic activity of certain polycyclic aromatic hydrocarbons can be inhibited by the presence of other similar hydrocarbons. The possible inhibitory effects of certain nonhydrocarbon components (probably oxygenated) of high boiling petroleum fractions have been noted (8). These observations all point to the possibility of finding effective additives for inhibiting carcinogenic activity in oils. The types of compounds €or this use are also suggested in part by the above work, as well as by current knowledge of growth inhibitors, such as quinones, and hydrocarbon reactive substances, such as polynitro compounds. Experiment8 along these lines have recently been undertaken in these laboratories. CONCLUSION
Five methods for the reduction of the carcinogenicity of certain high boiling petroleum products have been given a preliminary examination. Although the data are limited in respect to the number of different samples investigated, the evidence indicates that the methods described here may have some merit. The experimental error involved in the testing procedures precludes a t this time more positive conclusions on the relative effectiveness of the various methods. ACKNOWLEDGMENT
We wiEh to thank C. L. Brown, W. J. Sparks, R. E. Eclrardt, and RI. W. Swaney for their valuable support of this work. LITERATURE CITED
(1) Badger, G. >I., Brit. J. Cancer, 2, 309 (1948). (2) Crabtree, H. G., Ibid., 2, 281 (1948). (3) Cook, J. W., J . Chem. Soc., 1933, p. 1692. (4) Danetskaya, 0. L., Gigiena i Sanit., 1952, No. 10, p. 26. (5) Davis, W. W., Xrahl, 11.E., and Clowes, C. H. A., Science, 94, 519 (1941).
INDUSTRIAL AND ENGINEERING CHEMISTRY
October 1954
(6) Diets, W. A., and associates, IND. ENC.CHEM.,44, 1818 (1952). (7) Eby, L. T., Anal. Chem., 25, 1057 (1953). (8) Eby, L. T., Priestley, W., Jr., and associates, Ibid., 25, 1500 (1953). (9) Engelbreth-Holm, J., and Iversen, S., Cancer Research, 7, 372
(1947).
2213
(13) Smith, W. E., Sunderland, D. A,, and Sugiura, K.. Arch. I n d . H y g . and Occupational Med., 4, 299 (1951).
(14) Steiner, P. E., and Falk, H. L., Cancer Research, 11, 56 (1951). (15) Twort, C. C., and Twort, J. M., J. Hug., 29, 373 (1930). (16) Wanless, G . G., Eby, L. T., and Rehner, J., Jr., Anal. Chem., 23,
563 (1951).
(10) Hill, W. T., and associates, Ibid., 11, 892 (1951). (11) Riegel, B., and associates, Ibid., 11, 301 (1951). (12) Schonberg,A . , and lfustafa, A , , J . Chem. Soc., 1949, p. 1039.
ACCEPTED April 29, 1954. RECEIVED for review June 20, 1953. Presented a t t h e 124th Meeting, ACS, Chicago, Ill., September 1953
N-Fluoroalkvlanilines and Their NHydroxyalkyl Derivatives J
J
J
J
PREPARATION AND PROPERTIES J. B. DICKEY, E. B. TOWWE, M. S. BLOOM, G. J. TAYLOR', H. 31. HILL, R. A. CORBITT2, $1. A. MCCALL, AND W. H. MOORE Tennessee Eustmun Co., Division of Fustmun I o d u k Co., Kingsport, Tenn.
T
HIS paper describes the preparation and properties of a
number of N-fluoroalkylanilines and N-fluoroalkyl-N-hydroxyalkylanilines which have proved to be valuable coupling constituents for a series of gas- and light-fast azo dyes for cellulose acetate. The effect of these fluorinated couplers on the color and fastness properties of azo dyes has been described in another paper ( 3 ) . The N-fluoroalkylanilinee are a new class of compounds which were disclosed in recent patents from this laboratory ( 2 , 21). The iv-fluoroalkyl-N-b!.droxyalkylanilines were prepared by first treating aniline or a substituted aniline with a fluoroalkyl halide, t,hen treating the resulting N-fluoroalkylaniline with a hydroxyalkylating agent. For example, AT-[2,2,2-trifluoroethyl]N-[2-hydroxyethyl] aniline rTas prepared as follows:
treating with antimony trifluoride and using bromine as a catalyst (10). l-Chloro-2,2-difluoropropane was prepared in 60% yield by treating ZJ3-dichloropropene with hydrogen fluoride a t 120" C. for 15 hours. The reported yield a t 60" C. by this method was only 4% (6, 1 2 ) . The new compound, 3-brorno-lJl-difluoropropane,was prepared by the reaction of mercuric fluoride with 1,lJ3-tribromopropane, as described in a patent from this laboratory (2e). 1,1,3Tribromopropane, also not previously described, was prepared in good yield by the free radical reaction of bromoform with ethylene in the presence of acetyl or benzoyl peroxide.
(-_7j--~~~ + CF,CH,B~-,~ - - N H C H , C F ~
CHBrzCHzCHIBr
+ HgFz
--, CHF2CHzCHZBr
O-NHCH~CF, + CH,CH~ V-K ---,\ \d /CHzCF3
--,
CHzCHzOH
3-Chloro-lJl,l-trifluoropropane was prepared in 50% yield by the thermal chlorination of l,l,l-trifluoropropane at 380' C., as described in the literature (16). A 2 . 8 : 1 ratio of 3-chloro-l,lJltrifluoropropane to 2-chloro-l,lJ 1-trifluoropropane was obtained. l-Chlor0-3,3-difluorobutane was prepared in 45% yield by chlorinating 2,2-difluorobutane ( 1 9 )in a Muskat apparatus ( 1 8 )as described in the literature ( 1 7 ) . A 3:2 ratio of l-chloro-3,3difluorobutane to 3-chloro-2,2-difluorobutane was obtained. It
The various fluoroalkyl halides used, with their methods of preparation, physical constants, and references, are listed in Table I. I-Bromo-2-fluoroethane ( Y ) , 2-bromo-l,l-difluoroethane (8), and 2-chloro-l,l,l-t~rifluoroethane(11, 16) were prepared as described in the references. 2-Chloro1,l-difluoroethane was obtained from the General Chemical Division, Allied Chemical and Dye TABLE I. FLUOROALKYL H.4LIDES Boilitg Corp. 2-Bromo-l,l,l-trifluoroethaneTvas obtained Compound Point, C. nz$ Method of Preparation in the best yields by treating 1,2-dibromo-2,2CHzFCHzBr 69-73 CHzBrCHzBr f HgFz dichloroethane with a mixture of hydrogen fluoride, CHFzCHzCla 35-36 CHFzCHzBr 57-60 antimony trifluoride, and antimony pentachloride CFaCHZCl 6-8 and venting the hydrogen rhloride formed (21 ). CFaCHzBrb 29-33 I t was also obtained by adding hydrogen fluoride CHaCFzCHGlb 55-56 to 2-bromo-l,l-difluoroethylene, a method not CHaCFzCHzBra 76-77 1 ,3890 1.4050 CHF2CHzCHzBrb 92-94 previously described. CFGHzCHzCI 47-49 1.3350 l-Bromo-2,2-difluoropropane was prepared more 91-93 1.3709 CHaCFzCHzCHzClb readily and in better yield by treating l,2-dibromoCHaCFzCHsCHzCHzCI b 127-128 1 ,3848 2-chloropropane with mercuric fluoride than by 1 Present address, Eastman Chemical Products, Inc., 260 Madison Ave., New York 16, N. Y . * Present address, Eastman Kodak Co., Rochester, N. Y .
a
b
Obtained from General Chemical Division. Allied Chemical and Dye Corp. See Experimental.
Lit. Cited
