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Патент USA US2409316

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Patented Qct. 15,1946
2,409,315
n)
UNITED STATES ‘PATENT OFFICE
2,409,315
FLUOROACETAMIDES AND THEIR
‘
PREPARATION
George W.‘ Rigby and Herman E. Schroeder, Wil
mington, Del., assignors to E. I. du Pont de Ne
mours & Company, Wilmington, Del., a corpo
ration of Delaware
No Drawing. Application April 23, 1943,
1
Serial N0. 484,302
22 Claims. (Cl. 260-561)
This invention relates to the preparation of‘
?uorinated organic compounds and to new or
' hydrogen, alkyl, aryl, alkaryl and aralkyl and ad
mixing water therewith. These new reaction
ganic ?uorine compounds. ' More particularly,
the invention comprises a, new process for the
products. are N-substituted ?uoroacetamides.
A preferred form of the invention may be
preparation of ?uoroacetamides and includes new
carried out by reacting tetra?uoroethylene with
chemical products consisting of N-substituted' 5." an organic amine'containing amino-hydrogen in
?uoroacetamides.
‘
the presence of water and a mild base.
The poly?uoroethylenes suitable for use in this
It has previously been proposed to produce or
ganic ?uorine compounds by the reaction‘ of ‘fluo
rine with various organic materials.
invention may be represented by the general
Prior in
vestigations have shown that this reaction of ?u
orine is extremely energetic and generally causes
pyrolysis of the organic material, resulting in the
formation of carbon, tar or other undesirable
carbonaceous decomposition products.
Heretofore, the only practical method for pre
paring ?uorine containing organic compounds
formula CX2=CX2 where one X is selected from
‘the group consisting oflhydrog'en and halogen
and the other three X’s are ?uorine. Thusthe
formula may be written CFX=CF2 where X is
selected from the group consisting of hydrogen
15 and halogen. In the case of the tri?uoroethyl
enes, two ‘products may be obtained depending
upon the conditions and the course of the re
has been to replace chlorine or bromine with
?uorine by means of various inorganic reagents,
action.
They are illustrated by the following
equations:
,
'
such as hydrogen fluoride, silver ?uoride, anti
mony ?uoride, mercuric ?uoride and other me- 7 ‘
tallic ?uorides. However, such processes yield
mixtures of inert products, are very restricted in
application and involve considerable expense.
It is an object of this invention to provide a 25
new process for the preparation of organic ?uoro
acetamides. Another object of this invention is,
to obtain new compositions of matter consisting
It cannot always be predicted accurately be
forehand which amide will be obtained from a
particular tri?uoroethylene and amine. In cer
tain instances, a mixture of amides is obtained
‘of N-substituted ?uoroacetamides. Still another
object is to readily prepare N-substituted organic 30 which may be separated by fractional distilla
tion.
?uoroacetamides possessing many novel and use
The organic amines suitable for use in this in
ful properties. Other objects will appear here
ventionmay be any organic amine containing
inafter.
amino-hydrogen. The term “organic amine con
These objects are accomplished by reacting
taining amino-hydrogen” designates a primary
‘ a poly?uoroethylene containing at least three
?uorine atoms and an organic amine containing 35 or secondary amine which may be saturated or
unsaturated, aliphatic or aromatic, cyclic or het
amino-hydrogen with admixture of water there?
erocyclic, monoamine or polyamine.
to. The admixture of water may be prior to,
The N-substituted ?uoroacetamides prepared
during or subsequent to the reaction of the poly
in accordance with this invention may be repre
?uoroethylene and the amine.’ This reaction
produces N-substituted ?uoroacetamides.
The 40 sented by the general formula
pre?x “poly” as used herein refers to the num
ber of ?uorine atoms present in the ?uoroeth
ylene and not to polymeric materials.
‘
New reaction products are obtained by react
ing a poly?uoroethylene containing at least three
?uorine atoms, such as tetra?uoroethylene, and
an organic‘ amine of the general formula
.
45
‘
R!
where X is selected from the group consisting of
hydrogen and halogen and
R
HN/
.50
R!
where R’ is a member selected from the group
consisting of alkyl,_alkary1 and aralkyl and Risa
member selected from the group consisting of
is an organic radical corresponding to the par
ticular primary or secondary amine employed in
the reaction. ‘In the new products produced by
this invention, X may be hydrogen or halogen.
2,409,316
3
but is preferably fluorine, R’ is a member selected
from the group consisting of alkyl, alkaryl and
aralkyl and R is a member selected from the
group consisting of hydrogen, alkyl, aryl, alkaryl
4
autoclave which was swept out with nitrogen, and
then 50 parts of tetra?uoroethylene was added.
The autoclave was closed and heated at 100° C. for
8 hours with agitation. At the end of this time
practically no pressure remained in the autoclave.
The product was removed from the autoclave with
and aralkyl. It is to be understood that the term
“alkyr’ includes cyclic as well as acyclic radicals.
ether, washed with saturated aqueous potassium
In order to obtain the amides of the present
carbonate
solution, dried and recti?ed. The dis
invention, it is desirable that a small amount of
tillate consisted of 44.7 parts of recovered
water be present in the reaction mixture so that
the reaction is carried out under hydrous condi 10 n-butylamine together with 67.5 parts of N-n
butyl di?uoroacetamide boiling at 113° C130 mm.
tions. Sufficient water may be contained in the
leaving 4.8 parts of residue. The yield of amide
reagents as an impurity or as water of crystalliza
corresponds to 90% of the theoretical based on
tion, such as from the borax in, the examples.
the tetrafluoroethylene. The amide had the fol
Although, in the preferred embodiments of this
lowing properties and composition: 111325, 1.4112;
invention it is desirable to have present in the re-I
(1425, 1.1029; F, 24.49%; N, 9.44%,
action mixture the amount of water required for
the reaction (either as water of crystallization, as
an impurity in the reactants or added as such) it
is not essential for this reaction that any or all
Example 11
A high-pressure reaction vessel was charged
of the water required be present initially since the 20 with 65 parts of di-n-butylamine, 10 parts of
borax and 50 parts of tetra?uoroethylene and
same results can be obtained by watching the re
action product with an aqueous alkaline solution
as is illustrated in Example VI wherein none of
the water required was added to the reactants
and in Examples I and II wherein only a portion 25
heated at 75° C. for 8 hours. At the end of this
time the pressure in the vessel was negligible.
The product was removed and worked up as de
scribed in Example I. There was obtained 8.3
of the water required for the yield of product ob
tained was present initially. The proportion of
water may vary within relatively wide limits de
pending largely upon the nature of the reactants,
parts of unreacted di-n-butylamine and 63.8 parts
of N-di-n-butyl di?uoroacetamide boiling at 107°
C. at-1O mm.; 711,25, 1.4270, d425, 1.0158; F, 18.52%;
N, 6.71%.
but the amount of water should not be such as to 30
Example III
cause appreciable hydrolysis of the product. In
A mixture of 108 parts of monomethylaniline,
general, the molar ratio of water (present either
15 parts of borax and 50 parts of tetra?uoroethyl
ene was charged into a stainless steel autoclave
range of 0.1 to 2 and preferably in the range of .1 35 and the mixture heated with shaking at 150° C.
to 1. One reason why such small amounts of
for 24 ‘hours. Some pressure remained in the
water are applicable is that in case a basic inor
autoclave indicating incomplete reaction. The
ganic salt is used to neutralize the hydrogen
contents of the autoclave were removed with
halides water is formed and is thus available for
ether and recti?ed to yield 67 parts of unreacted
as an impurity, as water of crystallization or
added as such) to polyfluoroethylene is in the
40 monomethylaniline and 47.4 parts of N-methyl
further reaction.
The method for carrying out the reactions
di?uoroacetanilide, boiling at 94° C. at 1.5 mm. ;
varies to some extent with the'different amines,
11,325, 1.5036; d425, 1.2305; F, 20.87%; N, 8.23%.
but the usual procedure consists in charging a
Example IV
given amount, preferably an excess, of a primary
or secondary amine and a polyfluoroethylene con- 45 A stainless steel autoclave was flushed with ni
taini-ng at least three fluorine atoms, such as
trogen and charged with 80 parts of anhydrous
tetra?uoroethylene, with a small amount of water
diethyl ether, 10 parts of borax and 73 parts of
n-butylamine. Then the autoclave was closed,
sel and heating for several hours. It is desirable 50 cooled in Dry Ice, evacuated and charged with 58
to limit the amount of water in order not to de
parts of chlorotrifluoroethylene. The mixture
compose or hydrolyze the N-substituted ?uoro
was heated at 100° C. with shaking for 8 hours
and mild base into a high-pressure reaction ves
acetamides.
The temperature at which the reaction is ef
fected may be varied over a wide range, depend
and on opening the autoclave, there was no evi
dence of any unreacted chlorotri?uoroethylene.
mixture was ?ltered and the filtrate was
ing largely upon the nature of the reactants, the 55 The
recti?ed through an efficient column. Twenty
catalyst, the results desired and other conditions
?ve parts of fraction (I) boiling at 97°-120°
of the reaction. Although it is desirable to carry
C./ 10-12 mm. and about 17 parts of fraction (II)
out the reactions at an elevated temperature, the
boiling at 89.5°-90.7° C./0.5 mm. were obtained.
temperature should be below that at which de
The recti?cation was interrupted after obtain
composition of either the reactants or products '60 ing
fraction (I) in order to remove a considerable
occur. In general, considerable reaction is ob
amount
of solid which had separated in the still
tained at 35° C. or lower temperature, but usually
pot during the distillation. The solid was readily
it is desirable to heat the reaction mixture to 50°
removed by washing the mixture with water.
C. or higher in order to obtain an appreciable re
Fraction (1) was puri?ed by redistillation, boiling
The
preferred
tem65
action in a reasonable time.
point 98°/13 mm.; 11.1325, 1.4110; (1425, 1.1050; F,
perature range is 50°—200° C., but temperatures as
high as 250° C. are sometimes desirable.
25.42%; N, 9.95%; molecular weight 148 and
152. The analytical data and physical constants
The invention is further illustrated by the fol
indicate fraction (1) is N-n-butyl di?uoro
lowing examples in which the parts are by weight
70 acetamide. Fraction (II) was found to have the
unless otherwise speci?ed:
following physical properties: 111,25, 1.4431; d425,
Example I
1.1376; C, 43.00%; H, 6.71%; Cl, 18.18%; F,
11.83%; N, 9.48%; molecular weight 171 and 162
A mixture of 80 parts of diethyl ether, 10 parts
which indicates the material is N-n-butyl chlo
of borax and 73 parts of freshly distilled mono
n-butylamine was charged into a stainless steel 75 ro?uoroacetamide.
2,409,315
5
‘
sults are sometimes obtained by using a combina-'
tion of catalysts.
Example V ‘
A mixture of 80 parts of diethyl ether, 10 parts
of borax, 58 parts‘ of hexamethylenediamine and
50 parts of tetra?uoroethylene was heated in a
stainless steel autoclave at 50° C. for 8 hours.
After removing the unreacted diamine by distil
lation, the di-di?uoroacetamide of hexamethe
ylenediamine was recrystallized from benzene.
F, 29.37%.
1
-
.
Example VI
It. will be understood that the operating condi
tions may vary widely depending upon the nature
of the reactants and also upon the results desired.
The time required for carrying out the reactions
may vary from a few minutes to several days de
pending upon the nature of the reactants and the
other operating conditions, such as temperature,
pressure and catalyst.
".The reaction may be carried out in a closed
system, or the reaction may be carried out in the
A mixture of 20 parts‘of n-octylamine and 25
vapor phase by mixing the vapors of the organic
parts of tetra?uoroethylene was heated 4 hours
amine containing amino-hydrogen and the poly
at 100° C. The product Wasremoved with ether, 15 ?uoroethylene such as ‘tetra?uoroethylene, with
washed with a dilute aqueous sodium bicarbonate
a small amount of water and passing the
solution, dried and recti?ed. There was ob
mixture through a hot reaction tube which
tained 9.3 parts of N-n-octyl di?uoro-acetamide
if desired may contain a catalyst, In gen‘
boiling at 115° C./5 mm.; nD25, 1.4300; F, 16.9%.
the reaction is carried out under subatmos
Among the polyfluoroethylenes containing at 20 eral
pheric, atmospheric or superatmospheric press
least three ?uorine atoms which are applicable
sure in the range. of .1 to 350 atmospheres. The
in this invention are trifluorobromoethylene, tri
preferred pressuresrange is 1 to 200 atmospheres.
?uoroethylene, trifluorochloroethylene, ‘tetra
fluoroethylene and trifluoroiodoethylene. The
tetrahaloethylenes react more readily than tri
?uoroethylene, and tetra?uoroethylene is par
ticularly preferred, as it reacts the most readily.
The preferred amines for use in this invention
are alkylamines. However, the invention is ap
plicable to any organic amine containing amino
hydrogen including alkyl, dialkyl, methyl, di
methyl, ethyl, diethyl, methyl ethyl, propyl, di
propyl, methyl propyl, methyl butyl, amyl, di
amyl, hexyl, dihexyl, octadecyl, cyclopentyl,
cyclohexyl, allyl and methallyl amines, ethylene
diamine, 1,2-propylenediamine, 1,3-butylenedi
amine, tetramethylenediamine, pentamethylene
diamine, octamethylenediamine, decamethylene
The reactions may be carried out in any suit
able reaction vessel which is capable of with
standing heat and pressure, such as stainless
steel, iron, silver and aluminum. The reaction is
preferably carried out With agitation, although
agitation is not always necessary. The reaction
and the separation or'isolation of the products
may be carried ‘out simultaneously or in separate
steps. The products may be separated by ?ltra
tion, extraction, or distillation, depending upon
the nature of the products.
1
The present invention is useful for the pro
duction of a Wide variety of N-substituted ?uoro
acetamides.
The reaction of ammonia with poly?uoroeth
ylenes, e. g., tetra?uoroethylene differs from the
reaction of tetrafiuoroethylene with primary and
N ,N '-dimethyl . hexamethylenediamine, aromatic 40
secondary amines in that di?uoroacetamide is not
amines such as toluidines, N-methyl toluidine,
obtained.
When ammonia is reacted with tetra
benzyl amines, ' monoethyl aniline, naphthyl
fluoroethylene under anhydrous conditions, high
amine, N-methyl naphthylamine, amino acids
yields of a product, boiling at 73° C./9 mm..are
and esters.
A mixture of amines may be employed in the 45 obtained. Analyses, physical constants and mo
lecular Weight indicate that the product has an
present invention. It is usually desirable to use
empirical formula corresponding to CsHsFsNB,
a molar excess of amine rather than of the ex
presumably
a trimer of di?uoroacetonitrile.
pensive poly?uoroethylene, and the excess amine
diamine, and their mono-N-alkylated derivatives,
- The products of this invention are useful for
may also exhibit a catalytic e?ect. Sometimes it
is desirable to employ an organic solvent, such 50 various commercial purposes, such as in phar
maceuticals, plasticizers, and bactericides. The
as ethers, diethyl ether, dioxane and benzene.
N-substituted ?uoroacetamides may also be hy
It is usually desirable to use a mild alkaline re
drolyzed to yield ?uoroaeetic acids which may be
agent to remove the hydrogen halides, but such a
useful
as intermediates for preparing other com
basic catalyst is not always necessary as is illus
pounds.
trated in Example VI. However, when a mild al 55
The invention is particularly advantageous in
kaline reagent is not used it is desirable to add
that it o?ers a safe, ?exible, practical and eco
a larger excess of the amine. A wide variety of
nomical method of producing ?uorinated prod
catalysts are operable including borax, disodium
phosphate, various sodium and potassium salts
ucts of the character herein described. One of
the advantages of the invention is that the process
such as carbonate, bicarbonate, acetate, cyanide 60 may be operated with none or a relatively small
and hydroxide, various organic amines, such as
amount of catalyst and the reaction proceeds
tertiary amines, and an excess of the particular
smoothly andeasily without undesirable side re
amine employed may help in removing the hy
actions. Furthermore, the use of small amounts
drogen halides. Special signi?cance is attached
of catalyst reduces the time, temperature and
to the use of borax which contains water of
crystallization and is very convenient in the pres
ent process.
cost of operation.
_
As many apparently widely diiferent embodi
ments of this invention may be made Without de
The proportion of catalyst may vary within
parting from the spirit and scope thereof, it is to
relatively wide limits depending largely upon the
be understood that we do not limit ourselves to
nature of the reactants, although ei?cient reac 70 the speci?c embodiments thereof except as de
tion may be effected without the use of cat
?ned in the appended claims.
alysts. Generally speaking very desirable results
We claim:
may be obtained with the use of an amount of
1. A process for the production of ?uoroacet
amides which comprises reacting a poly?uoroeth
weight of the materials used. Advantageous re 75 ylene containing at least three ?uorine atoms
catalyst corresponding to about .01 to 20.0% by
2,409,315
7
and an organic amine containing amino-hydro
gen with admixture of water thereto.
2. A process for the production of ?uoroacet
amides which comprises reacting, in the presence
of water, a poly?uoroethylene containing at least
three ?uorine atoms and an organic amine con
taining amino-hydrogen.
3. A process for the production of ?uoroacet
amides which comprises reacting, in the presence
8
ethylene and an organic amine containing amino
hydrogen and subsequently admixing water
therewith.
11. In a process for preparing a ?uoroacet
amide by reacting a poly?uoroethylene contain
ing at, least three ?uorine atoms with an organic
amine containing amino-hydrogen with admix
ture of water thereto, the step of reacting said
poly?uoroethylene and said organic amine.
12. A ?uoroacetamide having the general for
of water and a basic catalyst, a poly?uoroethyl 10
mula
ene containing at least three ?uorine atoms and.
an organic amine containing amino-hydrogen.
4. A process for the production of fluoroacet
amides which comprises reacting at an elevated
temperature and under pressure, a poly?uoro 15 wherein the R substituents are aikyl groups.
13. N-di-n butyl difluoroacetamide.
ethylene containing at least three ?uorine atoms
14. A ?uoroacetamide having the general for
and an organic amine containing amino-hydro
mula
gen with admixture of water thereto,
5. A process for the production of ?uoroacet
amides which comprises reacting, in the presence 20
of borax, a poly?uoroethylene containing at least
wherein R is an alkyl group.
three ?uorine atoms and an organic amine con
taining amino-hydrogen.
'
15. N-n-loutyl di?uoroacetamide.
16. The process for obtaining ?uoroacetamides
6. A process for the production of ?uoroacet
which
comprises heating tetra?uoroethylene with
amides which comprises reacting, under hydrous 25
an alkylamine containing amino-hydrogen in the
conditions, a poly?uoroethylene containing at
presence .of water and a basic catalyst at a tem
least three ?uorine atoms and an organic amine
perature
within the range of from 50° C. to 200°
containing amino-hydrogen.
C.
under
a pressure within the range of from
'7. A process for the production of ?uoro
one to 200 atmospheres.
acetamides which comprises reacting tetra?uoro
17. The process for obtaining ?uoroacetamides
ethylene and an organic amine containing amino
which
comprises heating tetra?uoroethylene with
hydrogen with admixture of water thereto.
an
alkylamine
containing amino-hydrogen in the
8. A ?uoroacetamide of the general formula
presence of borax at a temperature within the
R
35 range of from 50° C. to 200° C. under a pressure
HorXg-N/
R!
where X is a halogen atom, R is selected from
the group consisting of hydrogen, alkyl and aryl
groups, and R,’ is an alkyl group.
9. A process for the production of ?uoro
within the range of from one to 200 atmospheres.
18. The process according to claim 17 wherein
the alkylamine is a dialkylamine.
19. The process according to claim 17 wherein
40 the aikylamine is di-n-butylamine.
20. The process according to claim 17 wherein
the alkylamine is a monoalkylamine.
acetamides which comprises reacting a poly
21. The process according to claim 17 wherein
?uoroethylene containing at least three ?uorine
the alkylamine is n-butylamine.
atoms and an organic amine containing amino
22. N-n-butyl chloro?uoroacetamide.
hydrogen and subsequently admixing water 45
therewith.
GEORGE W. RIGBY.
10. A process for the production of ?uoro
HERMAN E. SCI-IROEDER.
acetamides which comprises reacting tetra?uoro
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