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Патент USA US3087984

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United States Patent O?lice
1
3,087,974
PROCESS FOR MAKING HALOGENATED
ORGANIC COMPOUNDS
Murray Hauptschein, Glenside, and Arnold H. Fainberg,
Elkins Park, Pa., assignors to Pennsalt Chemicals Cor
poration, Philadelphia, Pa., a corporation of Pennsyl
vania
No Drawing. Filed Apr. 11, 1960, Ser. No. 21,112
24 Claims. (Cl. 260-653)
This invention relates to a catalytic process for the dis
proportionation and rearrangement of per?uorochloro
ethanes.
The per?uorochloroethanes (i.e. ethanes containing only
3,087,974
Patented Apr. 30, 1963
2
an exothermic reaction occurs accompanied by the evolu
tion of carbon monoxide and/or carbon dioxide together
in some cases with variable amounts of other products.
When the evolution of carbon oxides has substantially
ceased, the cataylst is ready for use.
Activated alumina which is required in the preparation
of the catalyst of the invention, is characterized, as is
well recognized in the art, by its relatively high surface
are as distinguished from non-activated forms such as
10 corundum or alpha alumina which are dense, low~surface
materials.
Typically, activated aluminas may have sur~
face areas ranging, eg from 10 to 300 square meters per
gram.
As is well known, activated aluminas are generally pre—
the elements chlorine, ?uorine and carbon) are widely 15 pared by the controlled dehydration or calcination of
used as refrigerants, heat transfer ?uids, dielectric ?uids,
hydrated aluminas which may be natural or synthetic.
aerosol propellants and the like. Commercially, per
Thus, for example, the controlled calcination of alpha
?uorochloroethanes are usually prepared by the ?uorina
alumina trihydrate or beta alumina trihydrate will pro~
tion of chlorinated ethanes with anhydrous hydrogen ?uo
duce a highly porous structure having high internal sur
ride in the presence of ?uorine containing metal salts, such
face area. The hydrated alumina starting material may
as antimony chloro?uorides.
be natural, such as ‘bauxite, or synthetically prepared
A disadvantage of such prior processes is that both the
such as by the precipitation of aluminum nitrate, alu
hydrogen ?uoride and the catalyst employed are highly
minum sulfate or other soluble aluminum salt to pro
corrosive and require special equipment and handling prea
duce a hydrated alumina gel which is then washed and
cautions. As the ?uorination proceeds from the lower 25 calcined under control temperature conditions to produce
the activated form.
to the more highly ?uorinated ethanes, it is necessary to
It is highly preferred to employ essentially unmodi?ed
additional ?uorine, still further increasing the corrosion
activated alumina, that is an activated alumina which con
and handling problems. Another drawback is the neces
tains at the most small amounts, e.g. one to two percent,
sity of separating hydrogen fluoride from the products 30 of other materials (other than inert residues such as car
following the ?uorination reaction. There is accordingly
bon from binders and the like). Desirably, the alumina
a distinct need for a method of preparing per?uorochloro
should be low in Na2O and Fe2O3. Although essentially
ethanes, particularly those of higher ?uorine content under
unmodi?ed activated alumina is preferred, in some case it
employ more and more drastic conditions to introduce
less drastic, less corrosive and more convenient conditions.
There is also need for a convenient process for rear
may prove desirable to employ an activated alumina con
ranging per?uorochloro ethanes into different isomeric
of other metals or metal oxides, such as chrominum
taining minor amounts, e.g. from one to twenty percent,
forms, c.g. the rearrangement of CClF2CCl2F into
oxide, cobalt oxide, molybdenum oxide and the like. The
CCl3CF3.
Such isomers often diifer signi?cantly from
presence of such metals or metal oxides will often modify
one another in chemical properties. The asymmetric
forms (unsymmetrical distribution of ?uorine and chlo‘
rine) for example are usually easier to ?uorinate further.
the selectivity and/or activity of the catalyst in a given
reaction.
The lower ?uorocarbons used in the treatment of the
activated alumina are relatively low molecular weight
?uorine containing carbon compounds usually not con
Usually, however, the symmetrical forms are produced
solely or in predominant yield in ?uorination reactions
and it is thus desirable to have an e?icient and economical 45 taining more than about 8 carbon atoms and preferably
of the order of from 1 to 4 carbon atoms. The treatment
of the activated alumina with the ?uorocarbon to pro
process for converting the symmetrical to the asymmetrical
form.
In accordance with the present invention, a simple,
duce the catalyst should be conducted in the vapor phase
and it is generally impractical therefore to employ higher
efficient vapor phase catalytic process has been discovered,
which substantially eliminates the handling of corrosive 50 molecular weight ?uorocarbons which are difficult or
impracticable to handle in the vapor phase.
materials, by which per?uorochloroethanes may be re
arranged, or converted through disproportionation re
As pointed out above, the ?uorocarbon employed for
actions, into a more highly ?uorinated state. In its gen
eral aspects, the process of the invention involves contact
ing a per?uorochlorethane having at least one ?uorine
atom and at least one chlorine atom with a specially
treated activated alumina cataylst in the vapor phase at a
temperature of 150° C. to 600° C. to produce ethanes
dilferent from the starting materials. As will appear from.
the preparation of the catalyst should not contain more
than one hydrogen atom. Apparently, the presence of
multiple hydrogen atoms in the molecule interferes with
a the activation reaction. Thus, for example when the ?uo
rine containing compound CH3CF2CI is passed over
activated alumina at a temperature of about 300° C., re
action apparently does occur as evidenced by the evolu
the subsequent description, the process of the invention 60 tion of H20 and CH2=CClF. Carbon oxides, however,
has many advantages in addition to the elimination of
the use of hydrogen ?uoride and corrosive ?uorine con
are not evolved and the alumina so treated, when tested
as a catalyst in the disproportionation or rearrangement
of per?uorochloroethanes shows essentially no activity.
Preferred ?uorocarbons for the treatment of the acti~
well as long catalyst life. The cataylst employed is rela 65 vated alumina to produce the catalyst are those which
tively cheap and convenient and easy to prepare.
in addition to carbon and ?uorine contain only elements
l The catalyst is prepared by treating activated alumina
selected from the class consisting of chlorine and hy
taining salts. Being a vapor-phase process, it is convenient
to operate; high conversions and yields are obtainable, as
with a lower ?uorocarbon (i.e. a ?uorine containing car
drogen, particularly ?uoroalkanes of this type. Thus,
bon compound containing not more than one hydrogen
included in this group are perfluorocarbons (i.e. con
atom) at an elevated temperature and continuing the 70 taining only ?uorine and carbon), per?uorochlorocar
treatment until the evolution of carbon dioxides has sub
boos (i.e. containing only carbon, fluorine and chlorine);
stantially ceased. During the course of such treatment,
per?uorohydrocarbons (i.e. containing only carbon, ?uo
3,087,974
3
4
travels down the bed in the direction of the gas ?ow.
This hot zone results from the rather strong exothermicity
of the activation reaction and care should be taken to
avoid the excessive temperatures in the hot zone where
rine and hydrogen); and per?uorochlorohydrocarbons
(i.e. containing only carbon, ?uorine, chlorine and hy
drogen); provided always that not more than one hy
drogen atom is present in the molecule.
Particularly preferred are the lower per?uorochloro
apparently most of the reaction is taking place.
As
pointed out above maximum bed temperatures in ex
cess of about 800° C. should be avoided, and for best
alkanes (i.e. alkanes containing only the elements carbon,
?uorine and chlorine). Desirably, the per?uoroehloro
alkanes employed should have one to six and preferably
results, the catalyst bed temperatures should not ‘be per
mitted to remain above about 500° C. for substantial
from one to three carbon atoms. Such compounds have
periods
of time. The maximum temperature reached in
10
been found to impart high activity to the catalysts, are
the hot zone will depend upon the initial catalyst bed
readily available, and relatively cheap, particularly the
temperature, the temperature and rate of ?ow of the
per?uorochloroalkanes containing one and two carbon
activating ?uorocarbon, the bed dimensions and the like.
In order to control maximum bed temperatures during
Specific examples of fluorocarbons suitable for the treat
ment of the activated alumina are CF2ClCFCl2; CF3CCl3; 15 the activation treatment it may be desirable to dilute
the ?uorocarbon vapors employed for the activation with
atoms.
CFZClCFZCI; CF3CFCl2; CFClzCFClz; CF2ClCCl3;
CFZCIZ; CFBCl; CFCl3; CFQHCI; CF3CFClCF2Cl;
C3Cl3F5;
CFCl-CFCl;
an inert gas such as nitrogen in order to moderate the
exothermicity of
such as cooling
20 order to remove
of the activation
the reaction and/or to employ means
tubes inserted in the catalyst bed in
the heat of reaction during the course
treatment.
Completion of the activation treatment is signaled by
a sudden drop or substantial cessation of the generation
In the preparation of the catalyst, before treatment with
of carbon oxides. The generation of carbon oxides may
the ?uorocarbon, it is desirable ?rst to dry the alumina
to remove adsorbed moisture. This may be accomplished 25 continue subsequently during the use of the catalyst, but
the rate of generation is very low relative to the rate of
by heating the activated alumina to a temperature of e.g.
generation during the activation treatment. In ?xed bed
300° to 600° C., preferably 350° to 550° C. for a suf
operations, the completion of the activation may also be
?cient time to insure the elimination of any free water,
e.g. ‘from 5 minutes to 5 hours.
Desirably, during the
observed by the hot zone reaching the exit end of the
drying operation, the activated alumina is swept with a 30 bed.
stream of an inert gas such as nitrogen.
Depending on the activating agent, the initiation
of the activation reaction may occur at a temperature
lower than that required to fully activate the catalyst. In
The treatment of the activated alumina with the ?uoro
such cases it may be necessary or desirable to successively
carbon is carried out in the vapor phase at elevated tem
peratures usually ranging from about 150° C. to 800° 35 raise the activation temperature (but not above about
800° C.) until the evolution of carbon oxides has sub
C. and preferably from 200° C. to 500° C. In most
stantially ceased.
The time required to complete the activation will de
perature, giving catalysts of optimum activity, will range
pend somewhat upon the temperature employed, the cata
from about 250° C. to 450° C.
40 lyst size, the length and other dimensions of the catalyst
An exothermic reaction occurs between the ?uorocar
bed and the like. Typical activation times under normal
cases, particularly with the ?uorochlorocarbons having
from 1 to 3 carbon atoms, the optimum activation tem
bon and the alumina as evidenced by a rise in tempera
conditions may range e.g. from 5 minutes to 5 hours.
ture in the catalyst bed. The minimum temperature at
which such a reaction may be initiated will vary depend
During the activation procedure, ?uorine derived from
the activating ?uorocarbon is apparently “?xed” in the
ing upon the ?uorocarbon employed. Reaction may be 45 activated alumina which shows a weight increase (dry
initiated at temperatures as low as 150° F. with materials
basis) during the activation procedure generally ranging
such as CF2HCl whereas with materials such as CF2Cl2
from 1% to 40%, and more usually from about 3%
or CF2ClCFCl2, minimum temperatures of about 200°
to 20%. During subsequent use, the catalyst may con
C. are required to initiate the reaction. In other cases,
tinue to show a very gradual additional increase in weight.
still higher temperatures may be required to initiate re 50
The pressure during the activation treatment is not
critical except in the sense that the treatment should be
action.
The maximum temperature during the activation treat
carried out in the vapor phase and accordingly super
ment should not exceed about 800° C. to avoid damage
atmospheric pressures suf?ciently high to cause condensa
to the catalyst. Indeed, in order to avoid reduction of
tion of the reactants or reaction products on the catalyst
activity, the catalyst should not be permitted to remain
at the operating temperature employed should be avoided.
at temperatures above about 500° C. for substantial pe
While atmospheric pressure operation will often be most
riods of time during the activation treatment. Thus, while
convenient and economical, sub-atmospheric and mod
temperatures of the order of 600 to 800° C. for a few
erate super-atmospheric pressures ranging e.g. from one
minutes resulting e.g. from the exotherm of the reaction
tenth of an atmosphere to ten atmospheres may be some
may be tolerated, longer periods at these high tempera 60 times desirable.
tures may damage the catalyst.
The remarkable catalytic activity of these catalysts for
The principal gaseous reaction products during the acti
the disproportionation and rearrangement of per?uoro
vation treatment are carbon oxides. These may be in
the form of carbon monoxide, carbon dioxide or both
chlorocthanes is not entirely understood. They have con
tetrachloroethylene, carbon tetrachloride, chloroform, and
chloro?uoroalkanes may also be produced.
prior catalysts.
siderably higher activity for such reactions than previous
and/or in the form of carbon oxide addition products, 65 ly known catalysts containing aluminum and ?uorine, such
particularly COC12 and/or COClF. It is understood
as aluminum ?uoride prepared e.g. by the tluorination of
that the term carbon oxide is intended to include such
AlCl3 or alumina ‘with hydrogen fluoride. Apparently,
addition products as well as carbon dioxide and carbon
the aluminum and the lluorine in the catalyst of the in
vention are associated in a different manner than in these
monoxide. Other products such as chlorocarbons, e.g.
Where the treatment of the activated alumina with the
?uorocarbon is carried out in a ?xed bed, the reaction
appears to proceed from the input to the exit of the
bed as evidenced by the appearance of a hot zone which
Aside from their simplicity of preparation and mode of
use, these catalysts also have the advantage of relatively
long life, having been found to be still very active after
several hundred hours of operation. \"v'hcn after pro
longed operation the activity of the catalyst begins to
3,087,974
5
6
decline, it is apparently the result of the gradual deposi
170 volumes of CFsCFCla (at standard conditions) per
volume of alumina per hour while maintaining the average
bed temperature at about 400° C. Vigorous reaction
tion of carbon. When this occurs the activity of the
catalyst can be readily restored by a relatively simple re
generation procedure involving the passage of oxygen or
oxygen containing gases (e.g. air) over the catalyst at tem
peratures e.g. from 300-800° C. and preferably 350° to
500° C. This results in the oxidation of the deposited
carbon restoring the catalyst to essentially its original
activity. Excessive temperatures should be avoided during
occurred, a hot zone moving down the bed as previously
described, the temperature at the hot zone rising at some
points to a maximum of 450° C. The principal gaseous
products of the activation ‘were carbon monoxide and
carbon dioxide in the ratio of 1:2 at the start falling to
l:4 near the end. Activation was complete in 1.5 hours.
the regeneration procedure so as to avoid damaging the 10
EXAMPLE D
catalyst.
The following examples illustrate the preparation of
catalysts useful in the process of the invention:
EXAMPLE A
An activated alumina was employed in the form of
Mr" X Vs" cylindrical pellets containing over 99% (H2O
Activated alumina of the type employed in Example A
in the form of cylindrical 1/’s" x 1A" pellets was heated
for 500° C. for 1 hour while sweeping with nitrogen, driv
15 ing off 9.8% of water. The bed temperature was reduced
to 300° C. and at this temperature a stream of
CFzClCFzCl vapors was passed through the bed at a space
velocity of 200 volumes of CFZClCFZCI per volume of
free basis) of alumina and low in sodium, iron and silica
(0.03% Na2O; 0.08% FezOla; 0.22% SiO2). Before dry
alumina per hour. Activation treatment was continued
ing it has a 26% weight loss on ignition at 1000° C. and a 20 under these conditions for 1.2 hours while the evolution
surface area of 231 square meters per gram.
of CO and CO2 in the ratio of 1:2.5 as the principal gase
The above activated alumina was dried by heating to
ous products. After 1.2 hours the temperature was raised
500° C. while sweeping with nitrogen for about one hour
to 400° C.; activation was complete in 1.5 hours. Only
a trace of tetrachloroethylene was formed during activa
resulting in the loss of 9.7% by ‘weight of water, based on
dry weight.
25 tion.
After drying, the activated alumina, in an electrically
EXAMPLE E
heated tube was treated with CF2ClCFCl2 vapors at a
Activate-d alumina in the form of Va" x ‘As'’ pellets con
space velocity of 180 volumes of CFgClCFClz vapor (at
standard conditions of temperature and pressure) per hour
taining precipitated chromium oxide was employed, ana
lyzing as follows on an H2O free basis:
per volume of alumina for a period of 0.8 hour. The bed 30
was maintained ‘at an average temperature of about 300°
C. during the treatment. At the outset a hot zone ap
proximately 50° C. hotter than the average bcd tempera~
ture formed at the inlet to the bed and moved progres
sively down the bed toward the exit as the activation treat
ment proceeded. Bed temperatures were measured in this
and succeeding examples by thermocouples placed in an
Percent
NagO
crzoa ___________________________________ __
Si02
35
0.6
____________________________________ __
0.15
CuO ____________________________________ __
0.005
Niz
F6283 ___________________________________
——————————————————————————————————— __
-—
.
external longitudinal slot in the heated tube.
During the activation treatment the principal products
A1203 _______________________________ __ Remainder
the ratio of about 2:1 together with smaller amounts of
tetrachloroethylene. At the end of about 0.8 hour, the
evolution of carbon oxides suddenly ceased simultaneously
in a weight loss of 0.9% H20. While maintaining the bed
temperature at approximately 400° C., a stream of vapors
of CF2ClCFCl2 was passed through the bed at a space
with the appearance of the hot zone at the exit end of the
velocity of 180 volumes of CF2ClCFCl2 (at standard
bed.
conditions) per volume of alumina per hour. After about
1 hour, the generation of carbon oxides ceased and activa
tion was complete.
A bed of this alumina was heated to a temperature of
were a mixture of carbon dioxide and carbon monoxide in 40 500° C. while sweeping with nitrogen for 1 hour resulting
During this treatment the activated alumina in
creased in ‘weight by about 16%, based on dry weight.
EXAMPLE B
An activated alumina of the type used in Example A in
The preparation of other suitable catalysts is described
in the copending application of Murray Hauptschein and
the form of is" x 1,43" cylindrical pellets was heated in a 50 Arnold Fainberg Serial No. 18,505, ?led March 30, 1960
fixed bed to 500° C. for 1 hour in a stream of nitrogen.
The bed was then cooled to about 260° C. A stream of
for Catalyst Composition.
Catalysts prepared as described above are highly active
nitrogen was bubbled through liquid CF2ClCFCl2 at about
for the conversion of per?uorochloroethanes having from
1 to 5 ?uorine atoms into more highly ?uorinated ethanes
»—l0° C. and this stream of nitrogen-diluted CFZCICFClZ
was then passed through the bed at a space velocity (based 55 through disproportionation reactions. Such dispropor
tionation reactions may be represented by the following
upon CFZClCFClZ) of about 50 volumes of CFZClCFClZ
vapor per volume of alumina per hour. ‘Under these con‘
equations:
ditions a mild exotherm was noted in the bed, the tempera
Equation ( l )
ture rising approximately 25° C. over the initial bed tem
perature of 260° C. As the treatment continued, the hot 60 Equation (2)
zone of the bed moved progressively down stream toward
the exit. The product gases from the activation treatment
were principally carbon dioxide and carbon monoxide in
the ratio of approximately 2:1 with lesser amounts of
tetrachloroethylene. The completion of the activation 65 Equation (4)
was shown by the sudden virtual cessation of generation
2CgC15F">C2Cl4F2 + C2Cle
2C2Cl4Ff’C2Cl3F3 + C2Cl5F
C2C13F3
of CO and CO2 and by the appearance of the hot zone at
Equation (5)
the exit of the bed.
2C2ClF5—>C2F6+CzCl2F4
EXAMPLE C
The
conversion
of per?uorochloroethanes having 3 and
70
4 ?uorine carbon atoms to those having 4 and 5 ?uorine
Activated alumina of the type used in Example A in
atoms respectively is of particular interest since the
the form of 1/s" x 1/a" pellets was heated to 500" C. for
1.3 hours while sweeping with nitrogen, driving off 10%
?uorination of these compounds by conventional methods
with hydrogen ?uoride and a ?uorine containing metal
by weight of water. A stream of vapors of CFBCFCIZ
were then passed through the bed at a space velocity of 75 salt requires relatively drastic conditions and because
3,087,974
7
8
these reactions are carried out in accordance with the in
Rearrangement activity versus disproportionation ac
tivity is also somewhat temperature dependent and de
pends also upon the choice of a particular catalyst among
those embraced Within the scope of the invention. Thus,
vention in high conversions and yields.
The disproportionation reactions of the invention may
occur between like molecules, for example between two
molecules of CFZClCFClZ or two molecule-s of CFaCFclz
as follows:
Equation (6)
2012c:circa-@2015,+c,c1,1=2
a chromium modi?ed catalyst may be employed to mini
mize rearrangement activity, in the event that predom
inantly disproportionation is desired, as will be illustrated
in the examples which follow.
Because of the ease with which the per?uorochloro
10 ethanes of lower ?uorine content disproportionate to pro
duce ethanes of still lower ?uorine content (see Equa
tions 1 and 2 above), the ultimate reaction products will
0n the other hand, mixed disproportionation reactions
often include perchlorocthane CZCG (or CClz:CCl2-I-Cl2
may occur between two isomers, or between two mole
cules of a different degree of ?uorination.
the foregoing are the following:
Examples of
resulting from splitting off of C12 from C2Cl6) even in
15 cases where the starting materials are relatively highly
lluorinated ethanes such as C2F3Cl3 or C2F4Cl2. This
results from additional step-wise disproportionation re
actions occurring simultaneously with the primary dis
proportionation.
20
The process of the invention is carried out by passing
the reactants in the vapor phase desirably with the ex
Equation (12)
CCl3CF3+CCl2FCCl3—> CzClzFr-k C2Cl6
clusion of moisture and oxygen through the catalyst bed
at catalyst bed temperatures of from 150° to 600° C.
and preferably from 225“ C. to 450° C. The reactants
25 may be preheated approximately to the desired catalyst
bed temperature before passing over the catalyst. In
some cases, the reactions involved are somewhat exo
thermic and it may be desirable in such cases to preheat
the reactants to a temperature somewhat below the de
30
Equation (15)
CCl2F C133 +CCl3CClF2—>C2ClF5+ CzCl5F
sired equilibrium catalyst temperature.
The factors governing the minimum catalyst tempera
ture of about 150° C. are reaction rate and the tendency
of high boiling products or reactants to condense on the
catalyst.
Generally speaking, at temperatures below
35 about 150° C., the disproportionation and rearrangement
reactions of the invention do not proceed at practical
rates. Likewise, at temperatures below 150° C. it be
comes dif?cult to avoid the condensation of ‘high boiling
compounds such as perchloroethylene or perchloroethane
which tends to inactivate the catalyst.
ried out in accordance with the invention, in accordance
At temperatures above about 600° C. the catalyst
with which molecules that are symmetrically arranged
life is shortened and there is also a tendency for the re
with respect to the distribution of chlorine and ?uorine
actants and the reaction products to undergo thermal
are converted to asymmetric forms. Typical of such re
cracking to ole?ns and/or methanes. In most cases, op
arrangement reactions are the following:
45 timum results are obtained in the preferred range of 225°
C. to 450° C.
Equation (17)
Reaction pressure is not critical except in the sense
CF2ClCFCl2—>CF3CCl3
that the reactants and the reaction products should be
Equation (18)
maintained in the vapor phase while in contact with the
In addition to the disproportionation reactions men
tioned above, rearrangement reactions may be also car
catalyst bed, and accordingly, super-atmospheric pres
It is to be understood that the various rearrangement 50 sures sufficiently high to cause condensation of the re
and disproportionation reactions described above may
actants or reaction products on the catalyst at the operat
often proceed simultaneously. For example, when
C2Cl4F2 is passed over the catalyst in accordance with
the invention it will disproportionate to
ing temperature employed should be avoided. While at
mospheric pressure operation will often be most con
venient and economical, sub-atmospheric and moderate
super-atmospheric pressures ranging, e.g. from one-tenth
and the C2Cl3F3 may then disproportionate to the next
of an atmosphere to ten atmospheres may sometimes be
higher ?uorinated ethane C2Cl2F4(+C2Cl4F2). Like
wise, when CF2ClCFCl2 is treated in accordance with the
invention, rearrangement to CF3CCl3 and mixed dispro
portionation between CF2ClCFCl2 and the rearrangement
found desirable.
The rate of flow of the reactants over the catalyst is
60 not critical and may vary within wide limits, depending
on the reaction temperature, desired conversion, and other
operating conditions. In most cases, practical ?ow rates
product CF3Cl3 occurs simultaneously together with dis
will lie within the range of from one hundred to ten
proportionation of CFgClCFClz with itself and of
thousand volumes of reactant vapor (calculated at 0° C.
CFaCCla with itself.
The various rearrangement and disproportionation re 65 and 760 mm. Hg) per volume of catalyst (bulk volume)
per hour. At these ?ow rates, the reaction time (catalyst
actions undergone by the per?uorochloroethanes in ac
cordance with the invention occur at different rates de
pending upon the reaction temperature and other con
contact time) will vary from a fraction of a second to
about a minute.
The reaction products and unreacted starting materials
ditions and thus, by controlling the reaction conditions,
leaving the catalyst bed may in most cases be condensed
e.g. temperature, a desired disproportionation and/or re
arrangement reaction may be caused to predominate. In
general, better conversions to disproportionation pro
ducts higher in ?uorine content are obtained at higher
by cooling and/ or compression to form a liquid one-phase
mixture from which the desired reaction products may be
separated by ordinary fractional distillation and the un
reacted starting material then recycled to the catalyst bed.
temperatures.
Perchlorinated materials or low ?uorine content materials
3,087,974
10
9
in accordance with the invention. In each of these exam
desired,
SUCh as be
CQCIG,
treated
C2C!4+Cl2,
by conventional
C2CI5F means
and C2C14F2
such as may
by HP
ples, the catalyst employed consists of about 172 grams of
Va " )1 Vs" cylindrical pellets of activated alumina pre
?uorination in the presence of ?uorine containing metal
pared as described in Example A by drying and then treat
salts, to upgrade them to ?uorine containing ethanes to be
used as starting materials in the process of the invention. 5 ing with CF2ClCFCl2 at a temperature of 300° C. until
The fractional distillation of the product m1xtures prothe evolution of CO and CO2 has substantially ceased.
duced in accordance with the invention is facilitated by
The catalyst is contained in a cylindrical 1%‘; inch ID.
the fact that hydrogen ?uoride is not used or produced
electrically heated tube to provide a catalyst mass 15356
in the process and thus does not appear as a di?‘icult-toinch in in diameter and 15 inches long. Liquid
remove contaminant in the reaction products.
19
cpaclcclzp
Catalytic Rearrangement and Disproporrionation Reac-
ls metered .via a needle valve. through a ?ow mete]: and a
lions Starting With CFECICFCIB
?ash vaporizer to the reactor mput. The reactor ex1t gases
are led to a Dry-Ice cooled receiver where the total prod
The catalytic treatment of the symmetrically ?uorochlo- 15 ‘1C? is collected The total Pmd‘lFe analyses 31% carried out
rinated ethane CFQCICFCIZ is a preferred embodiment of
was Vapor Fractometer and Infrared techniques The
the invention. The principal reactions apparently occurring when this compound is treated in accordance with
temperamies repoited are aveTage cataiyst bed teTflPel"
atures measuied ‘with sevFl'al thermoc?uples Placed in an
the invention are the following;
20
Eauation (17)
CF2ClCFC12—>CF3CC13 (rearrangement)
external longitudinal slot in the tube.
The results of eleven runs in which the catalyst temper
ature varied from 250° C. to 400° C. are summarized in
Table I.
TABLE I
Product composition, mole percent
Ex.
No
Temp,
°C.
Space
velocity
per
hour
CF30]; plus
0113011101 encircle CFgClCFzCl CFaCCh CFzClGFOl: oFiclocua
OFClqCCla
(Iron
C3010
02291101,
p [13
CFgClCFQCl
250
275
300
3011
300
345
350
17.5
355
100
1, 280
350
690
1, 230
680
1, 230
3211
3511
350
350
400
400
0.1
u. 4
1.0
0. 7
0.5
0. 4
2.3
1. 7
1.1
a. 6
2. a
20. n
21. 4
20. s
21. u
21.11
19. 6
23.1
23. 2
22. s
25.1
24. a
o. s
1.1
1. s
1. s
1.6
1. 0
2.8
2. e
2. 2
3.6
3. 4
50.1
48.1
54. 9
41.9
41.7
31. s
46.1
42. 7
38.7
as. 3
39. 2
11.1
12. s
e. 1
10. 5
12.1
33.1
8.1
12.0
18.2
s. 0
14. 0
12.2
12. 4
a. a
12. 5
12.7
11. 2
10. r
11. 4
12. 1
10. 7
11. 4
1. 5
2.1
2. e
2. 5
2.0
1. 3
2. 8
2. 6
2. 2
2. 7
2. 5
o. 5
0.8
1.3
1. 2
0.6
0. 6
2. 7
2. 6
o. 8
5. 7
4. 7
0. 7
0.1
1. 6
1.1
1.2
0.3
1. 5
1.1
1.9
1. a
0. 9
71
71
rs
22
as
52
r
69
64
as
64
2 Contains less than 10% of CFChCFClq.
Equation 1(8)
CF3CCI3+CF2CiCFCl2—->C2Cl2F4+C2Cl4F2
As is apparent from the data in Table I, the major prod_
duct in each case is CF3CCl3 produced by the rearrange
(disproportionation) 45 ment of the initial reactant CF2ClCCl2F in accordance
Equation (6)
with Equation 17. The second major product is C2Cl2F4
ZCFZCICFCLF} C2Cl2F4+C2C14F2
“
(dis r0 Ortionation)
p p
Equation (7)
(generally more than‘ 90% of the isomer CF3CECl2) pro
duced by dlsproportionauons 1n accordance with Equa
tions 8, 6 and 7. Small amounts of CF3CF2Cl are pro
50 duced in accordance with Equation 4 by the dispropor
2CF3CCl3—>C2Cl2F4+C2C_l1F2
_
'
(disproportlonatlon)
There is also further disproportionation of the C2F4Cl2
tionation of the C2Cl2F4 produced in situ.
Substantial
amounts of C2Cl4F2 are produced through the dispropor
tionations in accordance with Equations 8 and 6 while
further disproportionation of CZClqFZ in accordance with
compounds formed in situ to form the next higher ?uori
Equations 2 and 1 produces small amounts of CFCl2CCl3
nated ethane in accordance with the following reaction: 55 and C2Cl6. The CZCIG dissociates in accordance with
Equation 19 to produce small amounts of chlorine and
Equation (4)
C2Cl4.
It will be noted that as the temperature increases, the
Finally, the lower ?uorinated ethanes formed in situ
likewise undergo further disproportionation to form 60 conversion to CFBCCIB decreases (maximum at temper
atures of the order of 300° C.) while the conversion of
CZClEF and, Czcl?, While C2Cl6 may split off chlorine in
C2Cl2F4 increases. ‘Increasing temperature also favors the
accordance with the following reactions:
conversion to C2CiF5.
Equation (2)
Where a maximum yield of CF3CCl3 is desired, best re
Equation (1) 2C2Ci4F2-> C2C13F3
2C2Ci5F'9
5 +C2Ci4F2
Equation (19)
C2Clr> cc12=cc12+c12.
EXAMPLES 1 TO 11
The following examples 1 to 11 illustrate the above re
actions occurring during the catalytic treatment of
65 sults are generally obtained in the range of from 250° to
325 ° C. average catalyst temperature and most desirably
in the range of 270° to about 300° C. The following ex
ample illustrates the operation of the process under these
conditions over an extended period of time and demon
strates the sustained high activity of the catalyst.
EXAMPLE 12
Liquid CFQCICCIZF is fed to a vaporizer and pro-heater
where it is vaporized and preheated to a temperature of
75 230° C. and then passed through a bed of V1" x 'As" cat
3,087,974
11
12
alyst pellets of activated alumina treated as described in
Example B by passing a stream of CFZCICFCIZ in nitro
rearrangement and disproportionation reactor is produced
in the usual way by feeding perchloroethylene, chlorine
gen over the activated alumina pellets at a temperature
of 300° to 350° C. until the evolution of carbon oxides
and hydrogen ?uoride to a reactor containing antimony
chloro?uoride, to produce CFZCICCIZF in known manner.
The crude reaction mixture is passed through an HCl ab
has ceased. The total weight of the catalyst is about 215
sorber, and is then washed and dried. The CF2ClCCl2F
produced is then catalytically treated in accordance with
grams supported in a stainless steel tube having an inside
diameter of 1 inch to provide a catalyst bed 1 inch in di
ameter and 17 inches long. The average catalyst tem
perature was maintained at 28 “115° C. throughout the
run While the space velocity avenaged at about 500 vol
umes of CFZCICCIZF per volume of catalyst per hour.
conversion to CF3CCI3. The crude product includes
C2Cl3F3 (usually more than 90% of the isomer CF2CCl3)
plus C2Cl2F4 (usually more than 90% of the isomer
Operating continuously during a period of ?fteen days
CF3CFCIZ) as the major products; together with smaller
the invention under conditions to produce a maximum
amounts of C2Cl4F2, CzCCl5F, C2Cl6 and traces of
under these conditions, the conversion to CF3CCl3 is 56%
C2ClF5. Any CzCh, and chlorine produced may be re
initially and 53% at the end of this period. Conversion
to C2F4Cl2 (mostly CF3CFCl2) during the run holds 15 combined by irradiation to CgClB so as to avoid handling
these materials during subsequent treatment. This mix
steady at about 20%. Total conversion to CF3CCl3 and
ture is then condensed, neutralized and dried after which
C2F4Cl2 during the run averages about 75%. Only traces
the crude dry product is fractionially distilled to separate
of CF3CF2CI are obtained, while an average of about
C2Cl3F3 and C2Cl2F, as the major products plus small
12% C2Cl4F2; about 3% C2Cl5F; about 1% CZCIB, and
During this run a 20 amounts or traces of C2ClF5. The bottoms from the still
about 3% CC12=CCl2 are obtained.
consisting of the higher boiling more highly chlorinated
materials C2Cl4F2, C2Cl5F and C2Cl6, are then recycled
alyst (1500 pounds of CFZCICCIZF per pound of cat
as feed to the ?uorination reactor for conversion to
alyst). At the end of this run the catalyst is still highly
C‘FgClCClgF to supply additional feed to the dispropor
active.
25 tionation and rearrangement step. By this procedure, al
EXAMPLE 13 (CATALYST REGENERATION)
most quantitative conversion of the starting CF2C]CCl2F
A spent catalyst deactivated after prolonged operation
to eg 75% C2Cl3F3 (usually more than 90% CF3CCl3)
in the disproportionation and rearrangement of
and 25% CZCIZE; (usually more than 90% CF3CFCl2)
total of 720 pounds of CFQCICCIZF is passed over the cat
may be obtained.
CF2ClCFCl2 ‘as described in Examples 1 to 12 is regen
30
If it is desired to produce solely C2Cl2F.,, the following
erated as follows:
A spent catalyst (210 grams) dark gray to black in
integrated process may be employed. The CFZCICCIZF
feed to the catalytic disproportionation and rearrange
color as a ‘result of carbon deposited on the catalyst is re
generated by passing oxygen through the catalyst bed at
ment step is prepared as described above by the ?uorina
100 to 150 milliliters per minute while the catalyst tem
tion of perchloroethylene with HF. The CFZCICCIZF is
perature is raised from 300° C. to 400° C. over a period 35 then subjected to disproportionation and rearrangement
in accordance with the invention to produce a crude prod
of 18 hours. At 300° C. only a trace of CO2 is detected.
At 400° C. 25% CO2 is found in the exit gas initially,
uct containing C2Cl2F4 (usually more than 90%
this falling off slowly, 10% being measured after two
OF3CFCl2) and CZCI3F3 (usually more than 90%
hours and virtually nothing after a total of eighteen hours.
CF3CC13) as the major products; some C2Cl4F2, C2Cl5F,
Tests of the catalyst activity for the rearrangement and 40 C2Cl6 and traces of C2ClF5. The crude product is washed
and dried in the usual manner and then fractionally dis—
disproportionation of CF2ClCFCl2 before and after re
generation are made in accordance with the procedures
tilled to separate C2ClF5 and CZCI3F4 while the entire
of the ‘foregoing examples and the results of these tests
remaining product, including C2Cl3F3 (mostly CF3CCI3)
and low ?uorine content disproportionation products
are summarized in Table II below:
45 CZChFZ, CZCIEF and CzCla, is recycled to the ?uorination
TABLE II
reactor to be ?uorinated. In the ?uorination reactor, the
C2Cl4F2 and lower ?uorine content material is ?uorinated
to CFECICFCIZ. The rearrangement product CF3CCl3 is
Mole
Before regeneratlon_._.
After regeneration..."
Space
Mole
Mole
'I‘emp.,
veloc~
percent
percent
° C.
ity per
conver-
eonver
slon to
hour
slnn to
slon to
CFaCCl:
50 ?uorination conditions obtaining in the ?uorination reac
22
58
tor, the symmetrical isomer CF2ClCFCl2 is not ?uori
nated.
In this cyclic process, the output of the ?uorination re
15
24
25
42
78
69
300
300
300
300
360
720
360
720
CFzCCh CgChFl
36
‘27
54
44
percent
conver
plus
CzC11F|
?uoriniated to CF3CFCl2, while under the relatively mild
actor is CFZCICFCIZ plus CFSCFCI2 produced by the
?uorination of the rearrangement product CF3CCl3. The
?uorination reactor output is distilled to separate the
As may be seen, the activity of the catalyst, particularly
for the rearrangement reaction, is very substantially in
creased, the catalyst being restored close to its initial ac
tivit .
“yhen the catalyst was regenerated at a temperature of
450° C. in the same manner ‘and tested in the dispropor
60
lower boiling CFQCFCIZ from the CFZClCCIZF, the latter
being fed into the disproportionation ‘rearrangement re
actor while the former is combined with the CF3CFCl2
product from the dispropordonation-rearrangement re
actor.
By operating a process in this manner almost
quantitative conversion of CFZCICFCIZ to C2C12F4 (usu
tionation of C2Cl2F4 the activity was found to have in
creased still further, and in this case the regenerated ac
ally more than 90% of the isomer CF3CFCl2) may be
mainly CF3CCl3 a suitable integrated process is as fol
The catalytic treatment of CFBCFCIZ is another pre
ferred embodiment of the invention. The principal rcac<
‘achieved while avoiding entirely the rigorous ?uorination
tivity was greater than the activity of the catalyst when 65 conditions that would ‘be required to convert CF2ClCCl2F
directly to tetra?uorodich]oroethiane by direct ?uorina
freshly prepared.
tion. This results ‘from the fact that the asymmetrical
The above described process for the disproportionation
CF3CCI3 ?uorinates much more readily than the sym
and rearrangement of CFZCICFCIZ may be advanta
form CFQCICFCIZ, permitting the ?uorination
geously combined with conventional ?uorination proc 70 metrical
reactor to be operated under relatively mild conditions.
esses such as ?uorination with hydrogen ?uoride in the
Catalytic Rearrangement and Disproporrirmation
presence of ?uorine containing metal salts such as anti
Reactions Starting With CF3CFCi'2
mony chloro?uoride. When it is desired to produce
lows.
The feed material CFQCICFCIZ ‘for the catalytic
3,087,974
14'
Apparently, the major reactions occurring are in ac
tion occurring with this compound is treated in accord
cordance with Equations 18, 7 and 20; that is, the starting
CFZClCFZCl ?rst rearranges and the rearrangement prod
uct CF3CFCl2 then disproportionates with itself and with
ance with the invention is the following:
CFZClCFQCl.
Further disproportionation of the C2Cl3F3 produced in
In addition to the above reactions there is also some
situ occurs to some extent in accordance with Equation 3
further disproportionation of the lower ?uorine content
and still further disproportionation to higher chlorine con
tent ethanes may also occur in accordance with Equations
materials formed in situ to form still lower fluorine content
ethanes in accordance with Equations I. 2 and 3.
1 and 2.
At high temperatures, disproportionation of 10
CF3CF2Cl to C2136 may occur to a slight extent in accord
ance with Equation 5.
The following Examples 25—27 illustrate the catalytic
rearrangement
and
disproportionation
reactions
of
CFzClCFzCl.
EXAMPLES 25 TO 27
EXAMPLES 14 TO 20
In each of these examples, the catalyst employed con
The following examples illustrate the above reactions 15
sists of about 165 grams of vs" x 1/5" pellets of activated
occurring during the catalytic ‘treatment of CF3CFCI2 in
accordance with the invention. In these examples 180
grams of I/s" x 1/s" catalyst pellets is employed, the
catalyst having been prepared as described in Example C
by drying and then treating with CF3CFCl2 at a tempera 20
ture of 400° to 450° C. until the evolution of carbon
oxides has substantially ceased. The catalyst is contained
in a cylindrical 15/16" ID. electrically heated tube to pro
vide a catalyst mass 15/16" in diameter and ?fteen inches
alumina prepared as described in Example D by drying
and then treating with CF2ClCF2Cl at a temperature of
from 300° C. to 400° C. until the evolution of CO and
CO2 has substantially ceased. The catalyst is contained
in a cylindrical ‘016" ID. electrically heated tube to pro
vide a catalyst mass lain" in diameter and about 15 inches
long. CFzclCFzCl is metered through a ?ow meter to the
reactor input. The reactor exit gases are led to a cooled
long. CF3CFCl2 is metered through a flow meter to the 25 receiver where the product is collected and afterwards
analyzed. The results of three runs at a catalyst tempera
reactor input. The reactor exit gases are led to a cooled
ture
of 400° C. and at varying space velocities are suin
receiver where the product is collected and afterwards
marized in Table V below:
analyzed. The results of seven runs (Examples l4~20)
TABLE
at varying catalyst temperatures and space velocities are
summarized in Table III below:
30
TABLE III
Ex. N0.
Temp, ° C.
Space
Mole percent
velocity
per hour
conversion
to C2F5Cl +
CzClsFs
400
40
T5
400
400
400
450
450
80
170
360
170
360
66
56
40
59
46
450
1,000
28
T A B LE 1V
Space
Mole percent
Temp,
velocity
conversion to
° C.
per hour
(321F501 plus
40
80
170
360
No.
locity
‘’ O.
40
Mole
percent
conversion
conversion
to
(‘ligClCFaCl
to
to
CF30 FiCl
to products
CFZCFzCl CF3cFCi2
plus
0 F?CFCh
25 _ .
400
95
34
24
58
92
26A _
2L _
400
400
200
415
2?‘
18
‘28
32
55
50
S1
68
As may be seen, the conversion to CF3CF2Cl is favored
by lower space velocities (longer residence time).
Higher temperatures also tend to favor the conversion
to CF3CF2Cl. Accordingly, where it is desired to pro
duce predominantly CF3CFCl2 relatively low tempera
tures and short residence time should be employed, while
relatively high temperatures and long residence time
should be employed to favor the production of CF3CF2Cl.
Where it is desired to produce exclusively CFBCFZCI,
the CF3CFCl2 may be recycled to the catalyst together
50 with unreacted CF2ClCF2Cl.
Catalytic Disproportionari'on of Mixtures of
CFgCCIg and
Examples 28 and 29 illustrate the inter-molecular dis
proportionation between CF3CCl3 and CF2C1CFCI2 over
a catalyst prepared from a chromia containing activated
80
76
64
alumina.
45
Catalytic Rearrangement and Disproportionation
Reactions Starting With CFZCICFZCI
The principal reactions occurring when the symmetri
Mole
percent
'I‘ntal
conversion conversion of
Mole
percent
per
hour
CzclaFs
400
400
400
400
Space
ve-
35
EXAMPLES 21 TO 24
The catalyst employed was prepared in the same
manner as that used in Examples 14 to 20 except that the
alumina was treated with CF3CFCl2 at a temperature
of 300° C. rather than 400 to 450° C. The results of
four runs (Examples 21 to 24) at 400° C. and varying
Space velocities are summarized in Table IV below:
Ex. No.
Ex. Temp,
V
60
The reaction proceeds as follows:
Equation ( 8)
CF3CC13 +
C2Ci2F4+ C2C14F2
Further disproportionation of the C2Cl2F4 to CFSCFZCI
occurs together with some disproportionation of the lower
?uorine content materials to ethanes of still lower fluorine
cally ?uorochlorinated ethane CF2ClCF2Cl is treated in
content as previously explained.
accordance with the invention are the following:
For the purpose of comparison the same catalyst was
65
employed at the same space rate and similar temperatures
Equation ( l8) CFQClCFZC 1-) CF3CFCl2 (rearrangement)
to treat feed stocks consisting solely of CFgCiCFCig
Equation ( 7 )
(Examples 30-32) and solely of CF3CCl3 (Examples 33
ZCF3C1: Cl2—> CFBCFZCl +C2Cl3Fs
and 34).
(disproportionation)
In each of Examples 28-34 the catalyst employed
Equation (20)
70
consists of 183 grams of 1/8" x Ma" activated alu
(disproportionation)
mina pellets containing about 20% CrzOa. These pellets
(disproportion ation)
are treated as described in Example E by drying and then
treating with CFZCICFCIZ at a temperature of 400° C.
until the evolution of carbon oxides substantially ceases.
Equation (21)
3,087,974
15
ranged in a 1%!’ ID. electrically heated tube.
16
atoms at a temperature between 225° and 450° C. with
The feed stock is metered via a needle valve through a
?ow meter and a ?ash vaporizer to the catalyst bed ar
a catalyst reacting essentially unmodi?ed activated alu
mina with a lower ?uorocarbon containing only elements
The
reactor exit gases are led to a cooled receiver where the
selected from the class consisting of carbon, ?uorine,
product is collected and subsequently analyzed. The
chlorine and hydrogen and having not more than 1 hy
drogen atom, said reaction being carried out by contact
ing vapors of said ?uorocarbon with said activated alu
results of seven runs, with temperatures varying from
100° C. to 300° C. at a space velocity of 10 volumes of
reactant per volume of catalyst per hour, are summarized
in Table VI below:
mina at a temperature of the order of 150° C. to 800° C.
su?iciently high to initiate an exothermic reaction between
10 said ?uorocarbon and said alumina in the course of which
TABLE VI
reaction said ?uorocarbon is converted to carbon oxide
and said alumina increases in weight due to the associ
ation of ?uorine derived from said ?uorocarbon there
Mole percent con
Spaco
Ex.
Feed stock
Temp, vr-loci-
N0.
° C
version ottocd stock
to —
with, said contacting and the reaction between said ?uoro
' per
hour
15 carbon and said alumina being continued until the evo
CFgCCi: CQCizFt
lution of carbon oxide substantially ceases, whereupon
the thus treated alumina is an active catalyst for the con
28___ CF2CiCFCl2+C‘F3CGi3._A
100
10
0
39
29___
i ___
200
100
10
10
0
0
49
l
200
300
10
10
0
4
12
39
CFgClCFGlH-Cl’gCClg
CFzClCFCh"
.
31.-. CFQCICFC‘L.
32.-. CFzClCFClL
33.--
GFgCCl; ______ __
__-
200
10
________ __
3
34....
CFzCC‘ls ________________ __
800
10
________ __
13
version of per?uorochloroethanes into pcr?uorochloro
20
ethane products of a different type.
6. A method in accordance with claim 5 in which said
per?uorochloroethane starting material is one having the
formula CgFgClg.
7. A method in accordance with claim 5 in which said
The above examples show the chromia modi?ed acti
per?uorochloroethane starting material is one having the
vated alumina produces a catalyst which is quite inactive 25 formula C2F4Cl2.
for the rearrangement of CF2ClCFCl2 to CF3CCl3 in
8. A method in accordance with claim 5 in which said
contrast to similar catalysts prepared from substantially
unmodi?ed activated alumina (compare Examples 1 to
13). The chromia modi?ed catalyst employed in these
examples does, however, display activity in the dispropor
tionation of CF2ClCPCl2, CF3CCI3 and mixtures of these
per?uorochloroethane starting material is CFZCICFCIZ.
9. A method in accordance with claim 5 in which said
catalyst is periodically regenerated by treatment with an
30 oxygen containing gas at a temperature su?icient to ox
two isomers to C2Cl2F4 as shown by the data in Table
idize carbon deposited on said catalyst.
10. A method in accordance with claim 5 in which
VI.
the per?uorochloroethane starting material is employed
It is to be understood that many other variations and
embodiments are included within the scope of the in
vention in addition to those speci?cally described above;
the embodiments described are for the purpose of illus
said catalyst.
l1. A method for rearranging CF2ClCFCl2 to CF3CCl3
comprising the step of contacting said CF2ClCFCl2 at a
in the treatment of said activated alumina to prepare
trating and exemplifying the invention and the invention
temperature between 150 and 600° C. with a catalyst
is not limited thereto.
We claim:
reacting essentially unmodi?ed activated alumina with
1. A method for converting per?uorochloroethane
starting materials into perhalogenated ethane products
of a different type than the starting materials which corn~
a lower ?uorocarbon containing only elements selected
from the class consisting of carbon, ?uorine, chlorine and
hydrogen and having not more than 1 hydrogen atom,
said reaction being carried out by contacting vapors of
prises the step of contacting a per?uorochloroethane hav
said ?uorocarbon with said activated alumina at a tem
ing at least one ?uorine atom and at least one chlorine
perature of the order of 150° C. to 800° C. sut?ciently
45
atom at a temperature between 150° C. and 600° C. with
high to initiate an exothermic reaction between said
a catalyst prepared by reacting activated alumina with
?uorocarbon and said alumina in the course of which
a lower ?uorocarbon having not more than 1 hydrogen
reaction said ?uorocarbon is converted to carbon oxide
atom, said reaction being carried out by contacting vapors
and said alumina increases in weight due to the asso
of said ?uorocarbon with activated alumina at a tempera
ciation of ?uorine derived from said ?uorocarbon there
ture of the order of 150“ C. to 800° C. sufficiently high 50 with, said contacting and the reaction between said ?u
to initiate an exothermic reaction between said ?uorocar
orocarbon and said alumina being continued until the
bon and said alumina in the course of which reaction
evolution of carbon oxide substantially ceases, where
said ?uorocarbon is converted to carbon oxide and said
upon the thus treated alumina is an active catalyst for
alumina increases in weight due to the association of 55 the conversion of per?uorochloroethanes into per?uoro
?uorine derived from said ?uorocarbon therewith, said
chloroethane products of a different type.
contacting and the reaction between said ?uorocarbon
12. A method in accordance with claim 11 in which
and said alumina being continued until the evolution of
said CF2ClCFCl2 is contacted with said catalyst at a
carbon oxide substantially ceases, whereupon the thus
temperature between 225° C. and 450° C.
treated alumina is an active catalyst for the conversion
13. A method for rearranging CFZCICFZCI to
60
of per?uorochloroethanes into perhalogenated ethane
CFaCFClz which comprises the step of contacting said
products of a different type.
CFZClCFZCI at a temperature between 150 and 600° C.
2. A method in accordance with claim 1 in which said
with a catalyst reacting essentially unmodi?ed activated
starting per?uorochloroethane is one having the formula
alumina with a lower ?uorocarbon containing only ele
ments selected from the class consisting of carbon,
C2F3Cl3.
65
?uorine, chlorine and hydrogen and having not more
3. A method in accordance with claim 1 in which said
than 1 hydrogen atom, said reaction being carried out
per?uorochloroethane starting material is one having the
by contacting vapors of said ?uorocarbon with said
formula C2F4Cl2.
activated alumina at a temperature of the order of 150°
4. A method in accordance with claim 1 in which said
C. to 800° C. sufficiently high to initiate an exothermic
per?uorochloroethane starting material is CF2ClCFCl2.
70 reaction between said ?uorocarbon and said alumina in
5. A method for converting per?uorochloroethane
starting materials into per?uorochloroethane products of
the course of which reaction said ?uorocarbon is con
a different type than the starting materials which com
prises the step of contacting a per?uorochloroethane
verted to carbon oxide and said alumina increases in
weight due to the association of ?uorine derived from
having at least one ?uorine atom and at least two chlorine
said ?uorocarbon therewith, said contacting and the re
3,087,974
17
action between said ?uorocarbon and said alumina being
continued until the evolution of carbon oxide substan
tially ceases, whereupon the thus treated alumina is an
active catalyst for the conversion of per?uorochloro
ethanes into per?uorochloroethane products of a dif
ferent type.
14. A method in accordance with claim 13 in which
18
ture of from 150” to 600° C. with a catalyst reacting
essentially unmodi?ed activated alumina with a lower
?uorocarbon containing only elements selected from the
class consisting of carbon, ?uorine, chlorine and hydro
gen and having not more ‘than 1 hydrogen atom, said
reaction being carried out by contacting vapors of said
?uorocarbon with said activated alumina at a tempera
ture of the order of 150° C. to 800° C. suliiciently high
said CFzClCFgC]. is contacted with said catalyst at a
to initiate an exothermic reaction between said ?uoro
temperature between 225° to 450° C.
15. A method for disproportionating a compound of 10 carbon and said alumina in the course of which reac
tion said ?uorocarbon is converted to carbon oxide and
the formula C2F3Cl3 to a compound of the formula
said alumina increases in weight due to the association of
C2F4Cl2 which comprises the step of contacting said
fluorine derived from said ?uorocarbon therewith, said
C2F3C13 at a temperature between 150 and 600° C. with
a catalyst prepared by reacting essentially unmodi?ed
contacting and the reaction between said ?uorocarbon
only elements selected from the class consisting of carbon,
?uorine, chlorine and hydrogen and having not more
than ‘1 hydrogen atom, said reaction being carried out
by contacting vapors of said ?uorocarbon with said ac
of carbon oxide substantially ceases, whereupon the thus
treated alumina is an active catalyst for the conversion
activated alumina with a lower ?uorocarbon containing 15 and said alumina being continued until the evolution
of per?uorochloroethanes into per?uorochloroethane
products of a different type.
20. A method in accordance with claim 19 in which
tivated alumina at a temperature of the order of 150° 20
said CF2ClCFCl2 is contacted with said catalyst at a
C. to 800° C. sufficiently high to initiate an exothermic
temperature of from 225° to 450° C.
reaction between said ?uorocarbon and said alumina in
21. A method for converting per?uorochloroethane
the course of which reaction said ?uorocarbon is con
starting materials into per?uorochloroethane products
verted to carbon oxide and said alumina increases in
of a different type than the starting materials which com
weight due to the association of ?uorine derived from
prises the step of contacting a per?uorochloroethane hav
said ?uorocarbon therewith, said contacting and the
ing at least 2 ?uorine atoms and at least 2 chlorine atoms
reaction between said ?uorocarbon and said alumina
at a temperature between 150° C. and 600° C. with a
being continued until the evolution of carbon oxide
catalyst prepared by reacting essentially unmodi?ed ac
substantially ceases, whereupon the thus treated alumina
is an active catalyst for the conversion of per?uorochloro 30 tivated alumina with a lower per?uorochloroalkane, said
reaction being carried out by contacting vapors of said
ethanes into per?uorochloroethane products of a different
type.
16. A method in accordance with claim 15 in which
said C2F3Ci3 is contacted with said catalyst at a tem
perature between about 225° C. and 450° C.
17. A method for disproportionating compounds of
the formula C2F4Cl2 to compounds of the formula
per?uorochloroalkane with activated alumina at a tem
perature of the order of 200° C. to 800° C. sufficiently
high to initiate an exothermic reaction between said
per?uorochloroalkane and said alumina in the course
of which reaction said per?uorochloroalkane is converted
to carbon oxide and said alumina increases in weight
due to the association of ?uorine derived from said per
CZFSCl which comprises the step of contacting said
?uorochloroalkane therewith, said contacting and the
C2F4Cl2 at a temperature between about 150° to 600° C.
with a catalyst reacting essentially unmodi?ed activated 40 reaction between said per?uorochloroalkane and said
alumina being continued until the evolution of carbon
alumina with a lower fluorocarbon containing only ele
oxide substantially ceases, whereupon the thus treated
ments selected from the class consisting of carbon, ?uo
alumina is an active catalyst for the conversion of per
rine, chlorine and hydrogen and having not more than 1
?uorochloroethane starting materials into per?uorochlo
hydrogen atom, said reaction being carried out by con
roethane products of a di?erent type.
tacting vapors of said ?uorocarbon with said activated
22. A method in accordance with claim 21 in which
alumina at a temperature of the order of 150° C. to
said per?uorochloroethane is contacted with said catalyst
800° C. su?iciently high to initiate an exothermic reac
at a temperature between 225° C. and 450° C.
tion between said ?uorocarbon and said alumina in the
23. A method in accordance with claim 22 in which
course of which reaction said ?uorocarbon is converted
to carbon oxide and said alumina increases in weight 50 said per?uorochloroethane starting material is one having
the formula C2F3Cl3.
due to the association of ?uorine derived from said ?u
24. A method in accordance with claim 22 in which
orocarbon therewith, said contacting and the reaction
said per?uorochloroethane starting material is one having
between said ?uorocarbon and said alumina being con
tinued until the evolution of carbon oxide substantially
ceases, whereupon the thus treated alumina is an active
catalyst for the conversion of per?uorochloroethanes
into per?uorochloroethane products of a diiferent type.
18. A method in accordance with claim 17 in which
said C2F4Cl2 is contacted with said catalyst at a tem
60
perature of from 225° to 450° C.
19. A method for simultaneously disproportionating
and rearranging the compound CFzClCFClz which com
prises the step of contacting CFzClCFClz at a tempera
the formula C2F4Cl2.
References Cited in the ?le of this patent
UNITED STATES PATENTS
1,994,035
2,637,748
2,670,388
2,676,996
2,694,739
2,946,828
Croco ______________ __ Mar. 12, 1935
Miller _______________ __ May 5, 1953
Miller et al ___________ __ Feb. 23, 1954
Miller et al ___________ .._ Apr. 27, 1954
Pailthorp ___________ _- Nov. 16, 1954
Scherer et al. _________ __ July 26, 1960
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