OCTOBER
1961
NUCLEOPHILIC SUBSTITUTION I N FLUOROALKYL SULFATES
product which weighed 152 g. was washed with water and dried over calcium chloride. Twenty-one g r a m of the product was lost in the wash water. The latter gave a test for chloride ion and for fluoride ion, and was strongly acidic, perhaps because of difluoronitroacetic acid and chlorodifluoroacetyl fluoride. Distillation of the remaining 131 g. of product gave the following fractions: (a) 51 g. of trifluorochloroethylene. (b) 12 g. (15%) of 1nitroso-1,2,2-trifluoro-l,2-dichloroethane.(c) 14.5 g. (18.1%) ClCFL'FC12 (d) 19 g. (23.8%) of l-nitoso-1,2,2-trifluoro-l-
402 1
chloro-2-nitroethane. (e) 20 g. (25%) of l-nitro-l,l,2-trifluoro-2,2-dichloroethane. ( f ) 7 g. (8.75%) of 1,Zdinitro1,1,2-trifluoro-2-chloroethane.(g) 7.5 g. (9.35%) of residue.
Acknowledgment. We wish to acknowledge support of this work by the U. s. Army Quartermaster Corps under Dr. Juan C. Montermoso as scientific Officer. BOULDER, COLO.
[CONTRIBUTION FROM THE RESEARCH DIVISION,JACKSON LABORATORY, E. I. DU PONT DE NEMOURS AND co.]
Nucleophilic Substitution in Fluoroalkyl Sulfates, Sulfonates, and Related Compounds WERNER V. COHEN
Received February 9, 1961 New chemistry based on highly fluorinated alcohols is described. The difficult nucleophilic substitution at the carbonoxygen bond of polyfluoroalkoxy compounds takes place a t appreciably lower temperatures in the chlorosulfate and sulfate esters than in the tosyl esters. Fluoroalkylamines have been prepared from the corresponding alcohols going through one intermediate step.
Fluorinated alcohols containing the grouping fluoroalkylated on the nitrogen atom without apare much more acidic than ordi- parent difficulty.* nary alkyl alcohols being almost as acidic as phenol.' Formatim of jluoroalkyl halides. Selected fluoroLike the phenols, the fluoro alcohols are cleaved alkyl sulfates, sulfites, chlorosulfates, methaneonly with difficulty a t the carbon-oxygen bond, so sulfonates, and p-toluenesulfonates have been that direct exchange of the hydroxy function for prepared. The properties of some of these esters are halide, amino, or anilino groups has been reported given in Tables I and 11. The sulfate and chloroonly in isolated cases.2 sulfate esters proved to be useful as fluoroalkylatHalide substitution a t the carbon-oxygen bond of ing agents. Thus, lH,11~,3H-tetrafluoropropyl p-toluenesulfonate esters of fluorinated alcohols has chlorosulfate (I) was converted to the chloride (11) been %ccomplishedg-6 by reaction of these esters with lithium chloride in diethylene glycol a t 125', a with sodium iodide, lithium chloride, and lithium temperature which is unexpectedly low for the scisbromide in diethylene glycol a t elevated tempera- sion of the fluoroalkyl-oxygen bond. The same tures, usually in excess of 200'. This method has chloride made from the tosyl ester required a been extended to methane-, ethane-, and henzene- minimum temperature of 165'. sulfonate esterse of fluoro alcohols and has given LiCl satisfactory results in the formation of 1H,lH,HCFiCFzCHzOSOzCl +HCF2CFzCHzCl (61.2%) 125' wH-perfluoroalkyl halides.' I I1 It is rather surprising that the attempted reacKF tions of ammonia, methylamine and diethylamine -----f H( CFzCFz)&HzF (17.1%) at the fluoroalkyl-oxygen bond of tosyl esters have, H( CFeCF2)2CHzOSO&I I11 IV heretofore, been U ~ S U C C ~ S S ~ while U I , ~ ~ piperidine ~ and aniline under similar conditions have been Similarly, the chlorosulfate ester of lH,lH,5H-octafluoropentanol (111) was converted to the fluoride (1) R. N. Haszeldine, J . Chem. SOC.,1953, 1757; A. L. (IV) below 145'. The tosyl esters of this alcohol and H e m e and W. C. Francis, J. Am. Chem. SOC.,75,991 (1953). of 1H,1H,7H-dodecafluoroheptanolcould not be (2) A. M. Lovelace, W. Postelnek, and D. A. Rausch, Ali- made to react with potassium fluoride in diethylene phatic Fluorine Compounds, Monograph -138, Reinhold, p. 46. glycol a t temperatures up to 245', so that neither (3) G. V. D. Tiers, H. A. Brown, and T. S. Reid, J . Am. of the fluoroalkyl fluorides was formed. The shorter Chem. SOC.,7 5 , 5978 (1953). (4) W. F. Edge11 and L. Parts, J. Am. Chem. Soc., 77,4899 chain lH, lH,3H-tetrafluoropropyl tosylate (V), (1955). however, was suitable for fluoride formation react(5) E. T. McBee, D. H. Campbell, C. W. Roberts, J . Am. ing readily at 170'-210' (76%). It appears that Chem. SOC.,77,3149 (1955). ( 6 ) P. D. Faurote and J. G. O'Rear, Ind. & Eng. Chem., (8) H. A. Brown and G. V. D. Tiers, J. Org. Chem., 22,
-CF2-CH20H
49, 189 (1957).
(7) P. D. Faurote and J. G. O'Rear, J . Am. Chem. Soc., 78, 4999 (1956).
454 (1957).
(9) B. S. Marks and G. S. Schweiker, J . Am. Chem. Soc., 80, 5789 (1958).
4022
VOL.
COHEN
26
TABLE I
FLUOROALKYL SULFITES AND SULFATES [X(CF2),CHz0]pS0, _.
h
TL
1/
Formula
Mol. Wt.
H
2
1
CsHsFsS03
310.18
H
6
1
CiiHeF24SOa
B.P. 194 286
710.26
H
2
2
CsHsFsSOa
326.18
90/6.8mm.
H
4
2
Cl0H6FI6So4
526.22
105/2.1 mm.
H
10
2
C ~ Z H ~ F ~ ~ 1126.34 SO~
M.P. 123
F
1
2
C4H4FeSO4
150-154
a
262.14
Calcd. Found Calcd. Found Calcd. Found Calcd. Found Calcd. Found Calcd. Found
nY
C
H
F
S
23.2 23.1 23.6 24.1 22.1 22.7 22.8 22.5 23.4 23.3 18.3 17.8
1.9 1.8 0.8 1.1 1.8 2.1 1.1 1.2 0.5 0.6 1.5 1.8
49.0 48.1 64.2 62.6 46.6 45.3 57.8 56.3 67.5 63.4 43.5 44.2
10.3 10.1 4.5 4.2 9.8 9.9 6.1 5.8 2.8 2.8
Yield. %
-
-
1.3580
66.2
1.3341 1.3498 1.3379
65.1
1.3320
-
-
-
37.7
-
12.5
-
-
-
28
(>1.0)'
Yield and conversion not determined.
TABLE I1 FLUOROALKYL CHLORO SULFATES, TOSYLATES, AND METHANE SULFONATES X( CF&CH20SO2Y X n
Y
Formula
Mol. Wt.
M.P.
2 C1
CaH3FaS03Cl 230.58
H 4 C1
C5HaFsSOaCI 330.60
1 C1
CzHpF3S03Cl 198.56
H
F
H 2 C7Hj CiaHiaFiS03
286.25
386.27 H 4 C7Hj CI~HIOFSSO~ 8 C7H7 Ci6H1oFioSOa 586.31
H F
2 CHI
CaH5FjS03
228.15
F
3 CHB
C5HbFiS03
278.16
a
Conversion 52.5%.
-
R.P. 142-145
C
Calcd. Found 67-74/6mm. Calcd. Found 117-118 Calcd. Found 14-16 124-126/2mm. Calcd. Found 8-1 2 157/5 mm. Calcd. Found 44.5 171.5/2.3mm. Calcd. Found 112-114/70 Calcd. mm. Found - 78-80/6 mm. Calcd. Found
15.6 15.4 18.15 18.5 12.1 12.4 42.0 41.9 37.3 37.0 32.8 32.8 21.05 20.8 21.6 21.6
H
F
S
1.3 1.4 0.9 1.1 1.0 1.1 3.5 3.6 2.6 2.8 1.7 1.7 2.2 2.3 1.8 1.8
32.9 32.6 46.0 45.4 28.85 29.0 26.6 26.0 39.4 38.7 51.8 51.1 41.9 41.7 47.8 47.5
C 13.9 13.4 9.7 9.3
-
11.2 11.2 8.3 8.3 5.5 5.5 14.0 14.0
-
-
l
n
y
Yield, %
-
15.4 15.4 1.3705 55.0 10.7 10.0 1.3357 15.4b 17.9 17.8 1.3630 24.0b
-
-
-
-
1.4602 93.3
-
1.4335 80.0
-
-
-
-
-
-
-
96.P
-
-
1.3562 73.4 1,3440 49.0
Conversion not determined.
the long chain fluoroalkyl chlorosulfates possess weaker fluoroalkyl-oxygen bonds than the corresponding p-toluenesulfonates. A low reaction temperature of 120' was also sufficient in the reaction of lithium bromide with bis-lH,lH,3H-tetrafluoropropylsulfate (VI) to give the fluoroalkyl bromide (VII) (94.5%).
\7.1%
73.5%7
HCF&FzCHzNHCaH 6 VI11
LiBr
HCFzCF&HpOS020CH2CFzCFzH + 1200 VI
run with 28% ammonia in the presence of an anionic
HCFZCF2CH2Br dispersing agent provided a 46.5% yield. N-MethylVI1
Formation of jluoroalkylamines. The method used by Brown and Tiers to make N-1H,1H-heptafluorobutylanilines was adapted to the reaction of aniline with the tosyl ester (V) to give N-lH,lH,3H-tetrafluoropropylaniline (VIII). Substituting bis-1H,1H,3H-tetrafluoropropyl sulfate (VI) as the fluoroalkylating agent, an inferior yield was obtained. A very small amount of product was obtained on treating anhydrous ammonia with the tosyl ester (V) in a stainless steel bomb a t 175' for twenty-four hours (11%). The presence of water in the system proved to be beneficial, so that this same reaction
1H,1H,3H-tetrafluoropropylamine and N ,N-diethyllH,1H,3H-tetrafluoropropylamine were satisfactorily prepared with aqueous methyl- and diethylamine, respectively. Optimum reaction conditions were not explored, but yields of about 70% have been consistently obtained a t a reaction temperature of only 145' by substitution of benzene sulfonate esters for p-toluenesulfonate esters. Even the long chain 1H, 1H,9H-hexadecafluorononylamine prepared from the benzenesulfonate ester was isolated in satisfactory amount (70yo). An attempt to react aqueous trimethylamine with the tosyl ester (V) to gire the quaternary salt,
1961
OCTOBER
4023
XUCLEOPHILIC SUBSTITUTION I N FLUOROALKYL SULFATES
TABLE I11 FLUOROALKYL HALIDESH(CF~),CHZX ~
X
n
Formula
Mol. Wt.
B.P.
134.05
26
2
F
CaHaFo
2
C1
C S H ~ F ~ C ~150.51
54
C3H3F4Br
74
Br
2
I
2
C3H3FJ
4 F 4 C1
194.97 241.97
CsHsFo
234.07
C6H3F1C1
.
250.53
99
79 105
C Calcd. Found Calcd. Found Calcd. Found Calcd. Found Calcd. Found Calcd. Found
H
26.9 26.5 23.9 24.2 18.5 18.5 14.9 14.8 25.7 25.7 23.9 24.6
C 1 B r
F
2.2 70.9 2.5 69.6 - 50.5 - 50.3 1.5 39.0 1.8 38 7 1 . 2 31.4 1.3 30.1 - 73.1 - 72.5 2.0 60.6 1.4 56.4
-
-
-
ny
-
-
-
41.0 40.4
-
-
52.4 51.1
23.6 23.3 -
I -
14.2 12.9
