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Патент USA US2407129

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2,407,129
Patented Sept. 3, 1946
UNITED STATES PATENT OFFICE
2,407,129
PROCESS OF HALOGENATION
Anthony F. Benning, Woodstown, N. J., and
Joseph D. Park, Wilmington, Del., assignors to
Kinetic Chemicals, Inc., Wilmington, Del., a
corporation of Delaware
No Drawing. Application March 14, 1944,
Serial No. 526,475
3 Claims. (01. 260—653)
1
A. This invention relates to the preparation of
2
‘ ner of its practical application, particularly in
the proportions of the reactants, the tempera
ture, the pressure, and the exact method of pro
cedure, the following examples, in which the
parts are by weight, will serve to illustrate its
halogenated aliphatic hydrocarbons and, in par
ticular, to halogenated derivatives of methane.
B. It is, an object of the invention to prepare
halogenated derivatives of methane in which the
halogensare ?uorine, chlorine, or both. An
other object of the invention is to prepare such
compounds, many of which are disclosed in the
prior art, by a process having great advantages
over the prior art processes of preparing these
compounds.
practical application.
Example I
About 100 parts of activated carbon were im
1,0
pregnated with 35 parts of CI‘Fs by slurrying CI‘Fs
‘ with ether and pouring carbon into the slurry.
The solvent was then removed by heating at
INS-300° C. for several hours in the vacuum. The
ane simultaneously with chlorine and hydrogen
material thus treated was placed in an inconcl
?uoride in the vapor phase in the presence of a 15 jacketed carbon tube and heated to 275-300° C.
Through this tube was .then passed a mixture of
catalyst. The preferred catalyst is CI‘Fs.
D. According to the commercial process of
CH4, HF and chlorine, in the following ratios:
C. The objects of the invention are accom
plished, generally speaking, by reacting meth
preparing ?uorinated derivatives of saturated
aliphatic hydrocarbons, one use of which is as
refrigerants,“ the compounds are made from 20
chlorinated hydrocarbons using HF as a source of
?uorine and antimony halides as catalysts or ?u
Parts by weight
CH4 __________________________ "V. _______ __
Chlorine
_____
___
_____
4
60
HF _____________________________________ __ 30
orine carriers.
That operation is virtually an
It is advisable to ?rst start the flow of CH4, fol
lowed by HF and then by chlorine. The contact
exchange reaction carried out in the liquid
phase with the substitution of chlorine by ?uo 25 time was about two minutes. The reaction pro
ceeded very smoothly and at the end of‘ 3%
rine. The hydrocarbon which is ?uorinated
must, according to the teaching of the prior art
hours the reaction was discontinued. An inte
grating wet-test meter indicated that 15.6 parts
and according to the nature of the prior art
of methane had passed through the reaction
process, be chlorinated before it can be ?uo
30 tube. The eiiluent gas mixtures were led through
rinated.
‘
a copper ?ask (serving as a trap) into a scrub
E. According to our invention, a saturated hy
bing and drying system. The dried gases were
drocarbon is simultaneously chlorinated and flu
passed through a series of receivers cooled re
orinated in a single step process which has great
spectively with carbon dioxide ice in acetone and
advantage, over the processes known to the prior
art. This process is carried out on methane with 35 with liquid nitrogen. The pressure in the reac
tion zone was maintained at about 1 atm. abs. by
means of a pressure regulator at the end of the
HF and chlorine together in the presence of
chromium ?uoride. In the prior art process it
has been theoretically stated that the so-called
system. In the liquid nitrogen trap, 12 parts, of
methane were collected. The carbon ice-‘acetone
In this case the chromium ?uoride 40 cooled trap contained‘ 20.8 parts of material
catalyst is more a ?uorine carrier than a true
catalyst.
has no substantial action upon methane or even
upon chlorinated methane: It is, therefore, ap
parently a true catalyst. This process is carried
which had the following composition, obtained
by Podbielniak distillation:
CHCIFz _________________________ "parts-.. 0.4
out in the vapor phase.
CClzFz ___________________________ __do____ 6.4:
F. The chromium ?uoride catalyst may be im 45 CChF ____________________________ __do__‘__ 2
pregnated in a carbon carrier. It is prepared by
C'2C13F3 __________________________ .__d0__._._ 2
methods of impregnation which will be under
C014 ___________________ _._'_ _______ __do____
8
stood by persons skilled in the art. The products
C2Cls ____________________________ _..d0__.__
2
of the reaction contain a number of compounds
Organic loss ______________ __percent mole__ 6
together with unconverted reactants. The com 50 Conversion to fluorine compounds____do____ 9.6
ponents in the reaction product may be separat
Yield of ?uorinated compounds ____ __do____ 42
ed in the manner herein set forth, or by any
It will be observed not only that there were four
other satisfactory process of separation.
compounds containingboth chlorine and ?uorine
G. While this invention is susceptible of con
siderable variation and modi?cation in the man 55 in the product of reaction, but that the method
2,407,129
3
4
produced some carbon tetrachloride and some
L. The reaction products including the un
changed starting materials may be treated to
isolate the ?uoro derivatives either by absorption
perchlorethane.
Example II
of the inorganic materials in water or by con
A steel-jacketed carbon tube (with the jacket 5 densation and fractional distillation of the re
electrically insulated from the carbon tube) ?lled
action mixture. The unchanged CH4, C12, and
with activated carbon impregnated with CI'Fs
HF may be recycled.
(10% CrFa on carbon) was used. This tube was.
electrically heated, the ends of the carbon tube
,
M. A particular advantage of the invention is
that methane can be directly ?uorinated. An
serving as electrodes. At a, tube temperature of 1O other advantage of the invention is in the direct
340° C. the ?ow of CH4, HF and C12 was started
production from methane of CC12F2, a very val
in the order named, at the same ratio as that
uable compound. Another advantage of the in
used in Example I. A contact time of about
vention lies in this that methane is a much
three minutes was approximated. 42 parts of
cheaper starting material than the chlorinated
material were collected in a carbon ice trap and 15 materials which were necessary to ?uorination by
none in the liquid nitrogen trap. Substantially
the processes of the prior art. A surprising fea
all of this material was found to be CClzFz upon
ture of the invention is that the antimony cat
distillation with the Podbielniak apparatus. No
alysts which are useful in the processes of the
CChF was found.
prior art are ineffective in this process. Another
H. Super-atmospheric or sub-atmospheric 20 advantage of the invention is that in the prep
pressures may be used in carrying out this inven
aration of C‘ClzFz yields of the order of 35% were
tion although atmospheric pressure, in general,
obtained. Other catalysts which are useful in
is preferred. The ratio of the various reactants
the older processes of preparing such compounds
may be varied within wide. limits depending upon _
have been tried and found ine?ective. Another
the ?uorinated derivative of methane desired.
advantage of the invention is the provision of a
We have found the conditions used in Example II
new process for preparing the valuable compound
to be preferred for the production of CClzFz. By
CHC1F2 which has heretofore been prepared only
proper selection of the ratios of the various re
by the ?uorination of chloroform with ?uorinat
aotantsand the conditions of reaction, it is pos- I,
ing catalysts such as Sb halides and mercury
sible to selectively produce a. predominant quan '30 ?uorides.
tity of any compound which forms a constituent
N. As many apparently widely different em
of the reaction product.
bodiments of this invention may be made with
I. The reaction temperature may also be varied
out departing from the spirit and scope thereof,
over a wide range although temperatures above
it is to be understood that we do not limit our
550° C. are not suitable.
The temperature range '
selves to the speci?c embodiments thereof except
from 275° to 400° C. is to be preferred. For the
manufacture of CClzFz temperatures above 300°
C. are preferred.
J. The reaction time necessary may also be
varied depending upon the temperature of the
catalyst and on the particular derivative wanted.
However, in general, for the production of CC12F2
a catalyst temperature between 325°-450° C. and
contact times greater than 30 seconds will fur- _
nish the most satisfactory yields.
K. A suitable catalyst may be prepared from
an aqueous solution of chromic chloride by im
pregnation on carbon and then drying in vacuo
or in a stream of nitrogen heated to above 200°
C.
The proportion of the catalyst to carbon .
(chromium salt) may also be varied. In this in
vention 5-15% of C1‘F3, based on the weight of
carbon, has been satisfactorily used. The car
bon may be directly impregnated with CrFa by
pasting the material with ether or some other
inert solvent and then drying the mixture in a
current of inert gas, e. g., nitrogen, at tempera
tures of 350~400° C. Other catalyst supports may
.
be used.
as de?ned in the appended claims.
We claim:
1. A process for the preparation of halogen
ated saturated aliphatic hydrocarbons which
comprises reacting hydrogen ?uoride and chlo
rine simultaneously with methane at a tempera
ture of 325° to 450° C. in the presence of chr0
mium ?uoride and separating the products by
distillation.
’
2. A process for the preparation of di?uoro
dichloro-methane which comprises reacting hy
drogen ?uoride and chlorine simultaneously with
methane in the presence of chromium ?uoride at
a temperature of about 340° C. and separating
the products by distillation.
3. A process for the preparation of halogen
ated derivatives of hydrocarbons which comprises
reacting hydrogen ?uoride and chlorine simulta
neously with methane in the presence of chro
rnium ?uoride at a temperature between about
275° and 550° C. and separating the products by
distillation.
ANTHONY F. BENNING.
JOSEPH D. PARK.
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