unusual phase behavior (78). Nitroparaffins (77, 72) and nitriles, however, appear to interact very little with soap polar groups and their effects on grease dropping points are expected to lie closer to that projected for the solubility parameter of the mixed solvent when they appear in such systems. Literature Cited
(1 ) American Society for Testing Materials, Philadelphia, “1964 Book of ASTM Standards,” Part 18, D 566-42, 1964. (2) Bondi, A , , J . ColloidSci. 5 , 458 (1950). (3) Cox, D. B., J . Phys. Chem. 62, 1254 (1958). (4) Hildebrand, J. H., Scott, R. L., “Regular Solutions,” p. 124, Prentice Hall, Englewood Cliffs, N. J., 1962. (5) Hildebrand, J. H., Scott, R. L., “Solubility of Nonelectrolytes,” 3rd ed., Reinhold, New York, 1950. (6) Honig, J. G., Singleterry, C. R., J . Phys. Chem. 60,1114 (1956).
(7) Kaufman, S., Singleterry, C. R., J . Colloid Sci. 10, 139 (1955). ( 8 ) Kissa, E., Zbid., 17, 857 (1962). (9) Zbid., 19, 279 (1964). (10) Little, R. C., Zbid., accepted for publication. (11) Little, R. C., Singleterry, C. R., J . Phys. Chem. 68, 2709 f 1964). Zbid., p. 3453. Lubrication 51(1), 1 (1965). Mardles, E. W. J., Clarke, E. G., Zbid., 42B,295 (1946). Martin, E. P., Pink, R. C., J. Chem. SOC. 1948,p. 1750. Suggitt, R. M., A‘LGZ Sjokesman 24 (9), 367 (1960). Tughan, V. D., Pink, R. C., J . Chem. SOC.1951, p. 1804. Vold, M. J., Vold, R. D., Znst. Spokesman 13,lO (1949). RECEIVED for review October 18, 1965 ACCEPTEDApril 14, 1966 Division of Petroleum Chemistry, 150th Meeting, ACS; Atlantic City, N. J., September 1965.
ARY LAM I NO POLY FLUOROALKOXY
PHOSPHONITRILES A New Class of Potential Fire-Resistant Hydraulic Fluids and Lubricants GERHARD OTTMANN, HENRY LEDERLE, AND EHRENFRIED KOBER Chemicals Division, Olin Mathieson Chemical Corp., New Haven, Conn.
Several trimeric and tetrameric arylamino polyfluoroalkoxy phosphonitriles were synthesized. Preliminary evaluations indicated that this novel class of compounds possesses considerable potential for use as fireresistant hydraulic fluids and lubricants. Some of these fluids had autogenous ignition temperatures between 1 1 00” and 1 1 75’ F. A purified model product passed the hydrolytic stability test, showed good wear properties in the Falex test, and exhibited good thermal stability.
RIMERIC
0 (O-Aryl),
and tetrameric polyfluoroalkyl phosphonitrilates
T (Ia, Ib), aryl-1,l-w-tri-H-polyfluoroalkylphosphonitrilates (Ira, IIb), and aryl-1,l -di-H-polyfluoroalkyl phosphonitrilates (IIIa, IIIb) have recently been evaluated (7, 2, 3) and found to pass most of the specifications for fire-resistant naval hydraulic fluids ( 5 ) . H(CF2)xCH20\
P
4N\,OCHZ(CF~)~H P
I/ ‘OCH~(CFZ)XH
H(CF2)xCH20’1
N\.,/N
H(CF2IxCH20’ ‘OCH2(CF21xH
Ia
(WY
‘
(oCHi(cF2),Z)b
IIa. IIb. IIIa. IIIb.
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l & E C P R O D U C T RESEARCH A N D DEVELOPMENT
6; Z ; Z 6; Z 8; Z
=
H
= H = =
F F
To conserve space, abbreviated formulas, such as I1 and 111, are used here. However, the structures are actually cyclic sixand eight-membered rings of types Ia and Ib. The success encountered with these materials prompted us to synthesize and evaluate the closely related arylamino polyfluoroalkoxy phosphonitriles (IVa, IVb), a novel class of
+
Ib
+ + +
6 = y = 3; a y = 4 ; a + 6 = 8 6 = y = 3; a 6 = y = 4; a
IVa. y = 3; a b = 6; Z = H o r F IVb. y = 4 ; a - t 6 = 8 ; Z = H o r F
Experimental
Trimeric ~V-Methylanilino-2,2,2-trifluoroethoxy Phosphonitrile (IVa, R1 = CHI, R2 = H, x = 1, Z = F.) TYPICAL SYNTHETIC PROCEDURE. A 3-liter 3-necked flask, equipped with stirrer, condenser, and thermometer, was charged with 86.8 grams (0.25 mole) of trimeric phosphonitrilic chloride and 1000 ml. of toluene. Heating and stirring were started. When about 80' C. was reached, a mixture of 80.4 grams (0.75 mole) of l$r-methylaniline and 0.75 mole of triethylamine was added through a dropping funnel during a period of about 40 minutes. The mixture was then stirred, refluxed for 40 hours, and cooled, and triethylamine hydrochloride (59 .470 of theory) was removed by filtration. The filtrate was washed with cold water, dried over sodium sulfate, and then concentrated to about 450 ml. This solution was added dropwise to a suspension of sodium fluoroalkoxide in toluene, prepared from 30.0 grams (1.25 moles) of sodium hydride and 125 grams (1.25 moles) of trifluoroethanol (2, 3 ) . The reaction mixture was stirred and refluxed for 18 hours. After cooling, the product was washed with water and distilled through a Vigreux column, wrapped with a heating tape. The end of the distillation was indicated when the pressure increased significantly or when fumes became heavy in the receiver. Over-all yields, analyses, and physical properties are given in Table I . HYDROLYTIC STABILITYTEST. A product of type IVb (a = 2.01, R 1 = CH3, R z = H, x = 1, Z = F) was twice stirred with 2% by weight of Darco G-60 and filtered through filter aid. This product passed the hydrolytic stability test for naval hydraulic fluids ( 5 ); total acidity of the water layer was 2.04 mg. of KOH; acid number of fluid was 0.01 ; weight loss of copper specimen was 0.1 13 mg. per sq. cm. THERMAL STABILITY TEST. About 20 grams of the product used for the hydrolytic stability test were heated for 4 hours a t 350" C. in a nitrogen atmosphere. This resulted in a weight loss of 0.9970, an increase in kinematic viscosity from 100.4 to 149.4 cs. a t 100' F. and 10.24 to 11.42 cs. a t 210' F., a n increase in the ASTM slope from 0.73 t o 0.81, and an increase of refractive index from 1.4331 to 1.4413 a t 25" C. FALEXWEARTEST. The product used for the hydrolytic stability test was subjected to the Falex wear test ( 4 ) . The load was increased in eight hourly increments of 100 pounds each, resulting in only 42 notches takeup and a journal diameter decrease of 0.0002 inch. Under the same conditions, tricresyl phosphate, used as a standard, gave 142 notches take-up and a diameter decrease of 0.007 inch. AVTOGEKOLT IGXITIONTEMPERATURES. A few drops of the compound were introduced into a porcelain crucible contained in a n electric furnace (approximately 9.5 cm. high, 4.5 cm. in diameter) equipped with a thermocouple. In the vicinity of the expected ignition temperature, the temperature was raised a t a rate of about 5" F. per minute. The temperature a t which the first flash occurred was recorded. While this procedure is not so accurate as the ASTM procedure, it is much less time-consuming and it gave consisient results throughout (Table I). ANALYSIS.The number of arylamino groups present in the various products was determined by nuclear magnetic resonance spectroscopy. This permitted the calculation of the theoretical nitrogen values which, in general, agreed well with the experimental data obtained by the Kjeldahl method (Table I).
d
Y
Ln
0
YON. 010 000 .\\\ O d b
m\3m --N
I
l
l
mmtt-mm --N
Discussion
T h e physical properties of some arylamino polyfluoroalkoxy phosphonitriles (IVa, IVb) are compiled in Table I. ASTM slopes, densities, pour points, and autogenous ignition temperatures are essentially the same as found earlier (2, 3 ) for the aryloxy-substituted analogs of types I1 and 111, but viscosities of the arylamino-substituted products are in all cases considerably higher. The effect of structural modifications on the properties of fluids of type IV is similar to that reported for products of type I1 and 111 (2, 3 ) . Thus, products of type I V (a or b) with terminal CF3 groups have lower viscosities than those with terminal CFzH groups. Extension of the polyfluoroalkyl VOL. 5
NO. 2
JUNE 1 9 6 6
203
chains results in higher boiling points, viscosities, and densities and, a t the same time, lowers pour points and refractive indices. Increases in the ratio of arylamino- to polyfluoroalkoxy- substitution tend to increase boiling points, pour points, viscosities, and refractive indices, but to decrease densities. However, introduction of chlorine atoms in the aromatic rings of ,V-methyl-substituted products (R1 = CHB; Rz = C1) does not considerably improve the autogenous ignition temperature. A'-Methyl-substituted products (R1 = CH,) have lower pour points, viscosities, and autogenous ignition temperatures than those containing a secondary amino group (R1 = H ) . T h e trend of the property changes, as discussed, is generally independent of the size of the phosphonitrile ring; however, the tetramers have higher viscosities and lower, more favorable ASTM slopes than the corresponding trimers. Special purification techniques developed for fluids of types I, 11, and I11 ( 7 , 2, 3) to impart hydrolytic stability as required for naval hydraulic fluids ( 5 ) were also applied to the arylamino polyfluoroalkoxy phosphonitriles. I t was found that fluids of type I V require only one to two treatments with Darco G-60 to obtain hydrolytically stable materials, in contrast to the aryloxy-substituted products of types I1 and 111. This is probably due to the utilization of the basic anilines, rather than acidic phenols, as starting materials. As indicated by experimental results, the fluid product of run 7 had good thermal stability a t 350' C. and displayed considerably better wear characteristics than tricresyl phosphate.
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l & E C PRODUCT RESEARCH A N D DEVELOPMENT
Conclusions
The trimeric and tetrameric arylamino polyfluoroalkoxy phosphonitriles (IV) possess considerable promise for potential use as synthetic lubricants and hydraulic fluids. Hydrolytic stability, good wear properties, and thermal stabilities make them valuable candidates for hydraulic fluids and synthetic lubricants. Acknowledgment
The authors are indebted to R. Rittner for the elemental analyses, to H. Agahigian and D. Vickers for the nuclear magnetic resonance spectra, and to s. Kolback for technical assistance. literature Cited
(1) Kober, E., Lederle, H., Ottmann, G., ASLE Trans. 7, 389 (1964). (2) Kober, E., Lederle, H., Ottmann, G., U. S. Navy, Bureau of Ships, Final Rept. Project NObs 90092, Nov. 17, 1964. (3) Lederle, H., Kober, E., Ottmann, G., J . Chem. Eng. Data 11,221 (1966). (4) Ryan, V., Lubrication Eng. 2, 3 (September 1946). ( 5 ) Specification MIL-H-19457 B (Ships), Dec. 2, 1963. RECEIVED for review February 3, 1966 ACCEPTED April 5, 1966 Research sponsored by the U. S. Navy, Bureau of Ships, under Project NObs 90092. The opinions expressed by the authors are not necessarily those of the Navy Department.
