Dihalo-monophospha-s-triazines and their derivatives

This invention concerns itself with a class of novel dihalo-substituted monophospha-s-triazines as exemplified by the compounds 1-dichlorophospha-3,5-bis(perfluoro-n-heptyl)-2,4,6-triazine and 1-dichlorophospha-3,5-bis[C.sub.3 F.sub.7 OCF(CF.sub.3)CF.sub.2 OCF(CF.sub.3)]-2,4,6-triazine, as well as their thio and azido derivatives.

BACKGROUND OF THE INVENTION 
This invention relates in general to novel halogen-substituted 
monophospha-s-triazine compounds and to a method for their synthesis. In a 
more particular manner, this invention concerns itself with a method for 
synthesizing halo-substituted monophospha-s-triazines by effecting a 
reaction between a phosphorus pentahalide and a perfluoroalkyl or a 
perfluoroalkylether imidoylamidine and to novel triazine compounds 
produced thereby. 
The novel compounds of this invention, namely the holo-substituted 
monophospha-s-triazines, are best represented by 
1-dichlorophospha-3,5-bis(perfluoro-n-heptyl)-2,4,6-triazine and 
1-dichlorophospha-3,5-bis(perfluoroalkylether)-2,4,6-triazine, as well as 
their thio and azido derivatives. The holo-substituted 
monophospha-s-triazines provide a hydrogen-free system amenable for use as 
antioxidation and anticorrosion additives for perfluorinated lubricating 
fluids and greases. They are useful also as monomers for incorporation 
into polymers, the latter due to the presence of two replaceable halogens. 
Other applications will become readily appreciated and apparent to those 
skilled in the art. 
The present interest in the utilization of perfluoroalkylether type fluids 
for wide temperature range lubricating applications has created a need for 
effective antioxidant and anticorrosive additives to permit their 
functioning in the presence of metals and alloys at elevated temperatures. 
In oxidizing atmospheres and in the presence of titanium alloys, fluids as 
represented by Krytox 143AC (a product of E. I. DuPont de Nemours and 
Company, Wilmington, Del., U.S. Pat. No. 3,242,218) undergo extensive 
degradation and metal corrosion at temperatures below 288.degree. C. 
(550.degree. F.). Additives such as the 1-di(thiophenyl)phospha-3,5-bis 
(perfluoroalkyl)-2,4,6-triazines and the 
1-di(thiophenyl)phospha-3,5-bis(perfluoroalkylether)-2,4,6-triazines 
prevent fluid degradation and metal corrosion and, due to the presence of 
sulfur, also enhance the fluids' lubricity. 
SUMMARY OF THE INVENTION 
The present invention resides in the synthesis of a novel class of 
monophospha-s-triazines having the following structural formula: 
##STR1## 
wherein X is a halogen selected from the group consisting of chlorine and 
bromine and where R.sub.f is a perfluoroalkyl or perfluoroalkylether 
group. Examples of the R.sub.f substituent include groups having the 
formula C.sub.n F.sub.2n+1, where n is an integer from 1 to 10, inclusive; 
and CF.sub.3 (OCF.sub.2 CF.sub.2).sub.x OCF.sub.2, C.sub.2 F.sub.5 
(OCF.sub.2).sub.x OCF.sub.2 and C.sub.3 F.sub.7 [OCF-(CF.sub.3)CF.sub.2 
].sub.x OCF(CF.sub.3), where x is zero or an integer from the 1 to 20, 
inclusive. 
The novel synthesis for preparing the halogen substituted 
monophospha-s-triazines of this invention comprises the interaction of a 
perfluorinated imidoylamidine with phosphorus pentahalide in the presence 
of an acid acceptor. The reaction is generally carried out at temperatures 
of from about -20.degree. to 30.degree. C.; but, higher or lower 
temperatures may be utilized. 
Accordingly, the primary object of this invention is to provide a series of 
novel dihalo-substituted monophospha-s-triazine compounds. 
Another object of this invention is to provide a novel method for 
synthesizing dihalo-substituted monophospha-s-triazines by effecting a 
reaction between a phosphorus pentahalide and a perfluorinated 
imidoylamidine. 
Still another object of this invention is to provide a series of 
dihalo-substituted monophospha-s-triazines that find particular utility as 
antioxidant and anticorrosive additives for perfluorinated lubricating 
fluids. 
The above and still other objects and advantages of the present invention 
will become more readily apparent upon consideration of the following 
detailed disclosure thereof. 
DESCRIPTION OF THE PREFERRED EMBODIMENTS 
In accordance with this invention, it has been found that the above-noted 
objects can be achieved by effecting a reaction between a solvent mixture 
of phosporus pentahalide and a perfluoroalkyl or perfluoroalkylether 
imidoylamidine within an inert atmosphere at temperatures and for periods 
of time sufficient to achieve the synthesis of the novel 
dihalo-substituted monophospha-s-triazine compounds of this invention. 
Previously known monophospha-s-triazines, such as those disclosed in U.S. 
Pat. No. 4,166,071 to Paciorek et al, were substituted on the phosphorus 
ring atom by aryl groups and thus were not amenable to transformations 
into other types of compounds as is possible with the compounds of the 
present invention. In the compounds of this invention, the halogen groups, 
identified as X, can be replaced by N.sub.3, SR, or OR resulting in novel 
compositions. Examples of R include C.sub.6 H.sub.5 and R'--C.sub.6 
H.sub.4, where R' is an aromatic, alkyl, perfluoroalkyl or 
perfluoroalkylether moiety; and perfluoroaryl, such as C.sub.6 F.sub.5 and 
R.sub.f '--C.sub.6 F.sub.4 where R.sub.f ' is a perfluoroalkyl or 
perfluoroalkylether group. 
The general synthesis contemplated by this invention in synthesizing the 
dihalo-monophopha-s-triazines is best illustrated by the following 
equation 
##STR2## 
In the foregoing equation, R.sub.f is defined as above while X is chlorine 
or bromine. As shown by the equation, the phosphorus pentahalide is 
reacted with the perfluoroalkyl or perfluoroalkyletherimidoylamidine (II), 
giving the monophospha-s-triazine (I). The reaction is conducted in mixed 
solvents such as, e.g., tetrachloroethane and Freon-113 at temperatures 
ranging from -20.degree. to +30.degree. C. in the presence of an acid 
acceptor, such as triethylamine, to promote hydrogen chloride elmination. 
The reaction period is carried out for a period of time sufficient to 
effect the reaction and usually ranges from 24-72 hours, although longer 
or shorter periods can be used. The reaction is carried out in an inert 
atmosphere, e.g., under nitrogen, helium, or argon. In general, equimolar 
amounts of reactants are used, although it is often preferred to employ an 
excess of the phosphorus pentahalide reactant. 
The substitution of the halogen X in the dihalo-monophospha-s-triazine (I) 
by another group is carried out using either an alkali metal salt of the 
substituent or having an acid acceptor present. Thus, in substitution of 
the halogen by the thio-group, a solution of the 
dihalo-monophospha-s-triazine is reacted with thiophenol in a solvent such 
as tetrahydrofuran at temperatures ranging from about 0.degree. to 
50.degree. C. in the presence of triethylamine. The product formed is the 
thiophenyl derivative (III): 
##STR3## 
In a similar manner using lithium azide, the diazido triazine (IV) is 
formed from I: 
##STR4## 
In equations (B) and (C) above, the R.sub.f substituent is defined as in 
equation (A) and formula (I). 
The materials that are used in preparing the triazine products are known 
compounds that are described in the literature. For example, the 
perfluoroalkyl and perfluoroalkyletherimidoylamidines are disclosed in 
French Pat. No. 2,166,498 (1973).

A more complete understanding of the invention can be obtained by referring 
to the following illustrative examples which are not intended, however, to 
be unduly limitative of the invention. 
EXAMPLE I 
Under nitrogen by-pass, a solution of 
N'-(perfluorooctanoylimidoyl)-perfluorooctanoylamidine (14.40 g, 17.84 
mmol) and triethylamine (5.45 g, 53.66 mmol) in Freon-113 (65 ml) was 
added to a stirred solution of phosphorus pentachloride (4.50 g, 21.61 
mmol) in tetrachloroethane (80 ml) at 0.degree. C. over a period of 2 
hours. Stirring at 0.degree. C. was continued for an additional hour, 
followed by 16 hours at room temperature. After addition of Freon-113 (50 
ml), the precipitated triethylamine hydrochloride (6.35 g, 86% yield) was 
filtered off in an inert atmosphere enclosure. The solvents were then 
removed in vacuo, initially at room temperature, then at 50.degree. C., to 
leave a yellow oil. Distillation in vacuo gave 
1-dichlorophospha-3,5-bis(perfluoro-n-heptyl)-2,4,6-triazine (9.81 g, 61% 
yield), mp 30.degree.-31.degree. C., bp 80.degree.-84.degree.C./0.001 mm 
Hg. 
Analysis calculated for C.sub.16 F.sub.+ N.sub.3 Cl.sub.2 P: C, 21.21; F, 
62.91; N, 4.64; Cl, 7.83; P, 3.42; MW, 906.02. Found: C, 21.27; F, 62.55; 
N, 4.79; Cl, 7.59; P, 3.41; MW, 910. 
EXAMPLE II 
Under nitrogen by-pass, to a stirred solution of phosphorus pentachloride 
(2.15 g, 10.32 mmol) in tetrachloroethane (60 ml) at 0.degree. C., was 
added a solution of the imidoylamidine, C.sub.3 F.sub.7 
OCF(CF.sub.3)CF.sub.2 
OCF(CF.sub.3)C(.dbd.NH)--N.dbd.C(NH.sub.2)CF(CF.sub.3)OCF.sub.2 
--CF(CF.sub.3)OC.sub.3 F.sub.7 (10.02 g, 10.32 mmol), and triethylamine 
(3.64 g, 35.97 mmol) in Freon-113 (30 ml), over a period of 1 hour. 
Stirring at 0.degree. C. was continued for an additional 30 minutes 
followed by 66 hours at room temperature. The bulk of the solvents was 
removed in vacuo, followed by addition of Freon-113 (60 ml) to precipitate 
triethylamine hydrochloride (4.45 g, 100%). Distillation in vacuo of the 
filtrate afforded 1-dichlorophospha-3,5-bis[C.sub.3 F.sub.7 
OCF(CF.sub.3)CF.sub.2 OCF(CF.sub.3)]-2,4,6-triazine (4.91 g, 44.5 yield), 
bp 73.degree.-74.degree. C./0.001 mm Hg. 
Analysis calculated for C.sub.18 F.sub.34 Cl.sub.2 N.sub.3 O.sub.4 P: C, 
20.20; F, 60.37; Cl, 6.63; N, 3.93; O, 5.98; P, 2.89; MW, 1070.04. Found 
C, 20.64; F, 57.47; Cl, 6.39; N, 4.32; P, 2.82; MW, 1090. 
EXAMPLE III 
In an inert atmosphere enclosure, a solution of triethylamine (0.335 g, 
3.31 mmol) and thiophenol (0.4 g, 3.63 mmol) in tetrahydrofuran (10 ml) 
was added to a stirred solution of 
1-dichlorophospha-3,5-bis(perfluoro-n-heptyl)-2,4,6,triazane (1.50 g, 1.66 
mmol) in tetrahydrofuran (10 ml) over a period of 30 minutes. Immediate 
formation of a white precipitate and a yellow solution was observed. After 
addition, the reaction mixture was stirred at room temperature for 65 
hours; subsequent filtration gave triethylamine hydrochloride (0.44 g, 96% 
yield) and a yellow filtrate. The residue obtained on removal of solvents 
in vacuo was redissolved in a minimum of Freon-113 (2 ml) and passed 
through a 1.0.times.3.0 cm column of neutral Woelm alumina; a pale yellow 
solid resulted. A combination of recrystallizations from hot hexane and 
pentane, as well as sublimitation (100.degree.-120.degree. C., 0.001 mm 
Hg, 2 hours) afforded almost colorless crystals of 
1-di(thiophenyl)phospha-3,5-bis(perfluoro-n-heptyl)-2,4,6-triazine (1.25 
g, 71% yield), mp 65.5.degree.-67.degree. C. 
Analysis calculated for C.sub.28 H.sub.10 F.sub.30 N.sub.3 S.sub.2 P: C, 
31.92; H, 0.96; F, 54.10; N, 3.99; P, 2.94; MW, 1053.46. Found: C, 32.19; 
H, 1.12 F, 52.26; N, 3.68; P, 3.01; MW, 1080. 
EXAMPLE IV 
In an inert atmosphere enclosure, a solution of triethylamine (0.33 g, 3.26 
mmol) and thiophenol (0.40 g, 3.61 mmol) in tetrahydrofuran (13 ml) was 
added to a stirred solution of 1-dichlorophospha-3,5-bis[C.sub.3 F.sub.7 
OCF(CF.sub.3)CF.sub.2 OCF(CF.sub.3)]-2,4,6-triazine (1.76 g, 1.64 mmol) in 
tetrahydrofuran (25 ml) over a period of 30 minutes. Immediate formation 
of a white precipitate and yellow solution was observed. After addition, 
the reaction mixture was stirred at room temperature for 17 hours; 
subsequent filtration gave triethylamine hydrochloride (0.41 g, 91% yield) 
and a yellow filtrate. The residue obtained on removal of solvents in 
vacuo was redissolved in Freon-113 and passed through a 0.8.times.8 cm 
column of neutral Woelm alumina; a yellow liquid resulted which, on 
heating in vacuo (6 hr at 75.degree. C.), afforded some white sublimate of 
diphenyldisulfide. The residual yellow liquid was pure 
1-di(thiophenyl)phospha-3,5-bis[C.sub.3 F.sub.7 OCF(CF.sub.3)CF.sub.2 
OCF(CF.sub.3)]-2,4,6-triazine (1.25 g, 62% yield). 
Analysis calculated for C.sub.30 H.sub.10 F.sub.34 N.sub.3 O.sub.4 S.sub.2 
P: C, 29.60; H, 0.83; F, 53.06; N, 3.45; S, 5.27; P, 2.54; MW, 1217.48. 
Found C, 29.29; H, 1.16; F, 50.90; N, 3.61; S, 5.29; P, 2.38; MW, 1230. 
The antioxidative and anticorrosive action of 
1-di(thiophenyl)-phospha-3,5-bis[(C.sub.3 F.sub.7 OCF(CF.sub.3)CF.sub.2 
OCF(CF.sub.3)]-2,4,6-triazine is illustrated by a test given below carried 
out at elevated temperature in oxygen in the presence of a Ti(4Al,4Mn) 
alloy using Krytox 143A fluid, a product of E. I. DuPont de Nemours and 
Company, Wilmington, Del. A control run in the absence of the additive was 
conducted under otherwise identical conditions. In the test, a coupon of 
Ti(4Al,4Mn) alloy was suspended in a sealed tube containing either a fluid 
alone or fluid plus the additive. The exposure duration and temperature 
are denoted in the table below. Ihe action of the additive is clearly 
evident from the drastically reduced amount of volatiles formed, oxygen 
consumed, and the unchanged appearance of the metal coupon. 
TABLE 
__________________________________________________________________________ 
Addi- Expo- 
Oxygen Total product 
Fluid Amt 
tive 
Temp 
sure 
consumed 
formed 
type g wt % 
.degree.C. 
hr mg mg/g.sup.1 
mg mg/g.sup.2 
__________________________________________________________________________ 
Krytox 143AC 
4.79 
none 
316 24 75 15.7 
758.7 
158.4 
Krytox 143AC 
4.78 
1% 316 24 7.9 
1.7 
7.7 
1.6 
__________________________________________________________________________ 
.sup.1 Oxygen consumed in mg/g fluid employed. 
.sup.2 Products formed in mg/g fluid employed. 
EXAMPLE V 
In an inert atmosphere enclosure, to a slurry of lithium axide (0.40 g, 
8.17 mmol) in acetonitrile (10 ml) was added a mixture of 
1-dichlorophospha-3,5-bis(perfluoro-n-heptyl)-2,4,6-triazine (2.00 g, 2.21 
mmol) in acetonitrile (25 ml). The phosphatriazine was only partially 
soluble in the acetonitrile. After stirring at room temperature for 65 
hours, a white precipitate (0.32 g) of lithium chloride and unreacted 
lithium azide was filtered off. The pale yellow filtrate gave, on removal 
of solvents, a pale yellow oil which was redissolved in Freon-113 and 
purified by passing through a 1.0.times.4.0 cm column of neutral Woelm 
alumina. Distillation gave 
1-diazidophospha-3,5-bis(perfluoro-n-heptyl)-2,4,6-triazine as a colorless 
liquid which solidified on cooling (1.30 g, 64% yield), bp 
85.degree.-90.degree. C./0.001 mm Hg; mp 35.degree.-36.degree. C. 
Analysis calculated for C.sub.16 F.sub.30 N.sub.9 P: C, 20.91; F, 62.01; N, 
13.71; P, 3.37; MW, 919.16. Found: C, 20.37; F, 62.49; N, 12.99; P, 3.33; 
MW, 970. 
While the invention has been described with particularity in reference to 
specific embodiments thereof, it is to be understood that the disclosure 
of the present invention is for the purpose of illustration only and is 
not intended to limit the invention in any way, the scope of which is 
defined by the appended claims.