Organic compounds -- part of the class 532-570 series – Organic compounds – Halogen containing
Reexamination Certificate
1999-09-21
2001-02-06
Siegel, Alan (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Halogen containing
Reexamination Certificate
active
06184426
ABSTRACT:
This application represents a national filing under 35 USC 371 of International Application No. PCT/US98/05541 filed Mar. 19, 1998, and claims priority of Russian application No. 97106117 filed Mar. 24, 1997.
FIELD OF THE INVENTION
This invention concerns a process for the antimony pentafluoride catalyzed addition of hydrofluorocarbons across the carbon—carbon double bond of fluoroolefins.
BACKGROUND
Processes for the addition of 1,1,1-trifluoroethane to fluorinated olefins using antimony pentafluoride as a catalyst have been described (see G. G. Belen'kii and L. S. German,Soviet Scientific Reviews, Sect. B, pp. 195-6, M. E. Volpin ed., (Harwood Academic Publishers, 1984). Processes for the addition of trifluoromethanes, including CHF
3
, to certain fluorinated olefins using aluminum chlorofluoride as a catalyst have also been described (see U.S. patent application Ser. No. 60/000,720 and International Application No. PCT/US96/10872). Hydrofluorocarbons can be prepared by both processes.
Hydrofluorocarbon products are useful as refrigerants, fire extinguishants, heat transfer media, propellants, foaming agents, gaseous dielectrics, sterilant carriers, polymerization media, particulate removal fluids, carrier fluids, buffing abrasive agents, displacement drying agents and power cycle working fluids. There is an interest in developing more efficient processes for the manufacture of hydrofluoroalkanes.
SUMMARY OF THE INVENTION
A process is provided for forming an adduct of the formula RR
1
R
2
CCR
1
R
2
F or (FR
1
R
2
CCRR
2
CH
2
)
2
wherein R is selected from the group consisting of CH
3
, CH
2
F, C
2
H
4
F and F(CF
2
)
n
CH
2
CH
2
where n is an integer from 1 to 10, each R
1
is independently selected from the group consisting of H, Cl, F and CF
3
and each R
2
is independently selected from the group consisting of H, F and CF
3
. The process comprises reacting a saturated compound of the formula RF with an olefin of the formula R
1
R
2
C═CR
1
R
2
in the liquid phase in the presence of antimony pentafluoride catalyst; provided that when (FR
1
R
2
CCR
1
R
2
CH
2
)
2
is formed, the saturated compound is CH
3
CHF
2
or CH
2
FCH
2
F and anhydrous HF is present.
DETAILED DESCRIPTION OF THE INVENTION
This invention provides a liquid phase process for the addition of (a) saturated compounds of the formula RF, where R is selected from the group consisting of CH
3
, CH
2
F, C
2
H
4
F and F(CF
2
)
n
CH
2
CH
2
, where n is an integer from 1 to 10, to (b) olefins of the formula R
1
R
2
C═CR
1
R
2
where each R
1
is independently selected from the group consisting of H, Cl, F and CF
3
and each R
2
is independently selected from the group consisting of H, F and CF
3
; to form adducts of the formula RR
1
R
2
CCR
1
R
2
F or (FR
1
R
2
CCR
1
R
2
CH
2
)
2
in the presence of antimony pentafluoride catalyst (provided that when (FR
1
R
2
CCR
1
R
2
CH
2
)
2
is formed, the saturated compound is CH
3
CHF
2
) or CH
2
FCH
2
F and anhydrous HF is present).
Examples of olefins of the formula R
1
R
2
C═CR
1
R
2
which can be used in the process of this invention include CF
2
═CF
2
, CF
3
CF═CF
2
, CClF═CF
2
, CClF═CClF, CHF═CF
2
, CH
2
═CF
2
, CF
3
CH═CF
2
, CHF═CFCF
3
and CH
2
═C(CF
3
)CF
3
. Some of the olefins are commercially available, the others can be prepared by known methods.
Examples of saturated compounds of the formula RF which can be used in the process of this invention include CH
3
F, CH
2
F
2
and CH
3
CHF
2
.
Solvents or diluents may be employed in the process of the present invention. The solvent or diluent is selected so that it will not be reactive in the process or lead to the deactivation of the antimony fluoride catalyst. Suitable solvents or diluents may be selected from the group consisting of perfluoroalkanes or perfluoroethers (e.g., perfluorocyclobutane); the cyclic dimer of hexafluoropropene (i.e., the isomeric perfluorodimethylcyclobutanes); perfluoroethers or perfluoro tertiary amines. Preferred on the basis of its ready availability to those skilled in the art is the cyclic dimer of hexafluoropropene.
In one embodiment a one to one adduct of the saturated compound and the olefin is formed. It is noted in this regard that the saturated compounds of the formula F(CF
2
)
n
CH
2
CH
2
F can themselves be produced as one to one adducts. For example, the addition reaction of CH
2
FCH
2
F to CF
2
═CF
2
can be used to produce F(CF
2
)
2
CH
2
CH
2
F.
In a second embodiment of this invention the addition of the hydrofluorocarbons CH
3
CHF
2
and/or FCH
2
CH
2
F to olefins of the formula R
1
R
2
C═CR
1
R
2
in the presence of antimony pentafluoride can be done in the presence of anhydrous HF. The molar ratio of HF:SbF
5
is in the range of 10:1 to 40:1, preferably 20:1. The addition product or adduct is (FR
1
R
2
CCR
1
R
2
CH
2
)
2
. Without wishing to be bound by theory, it is believed that when CH
3
CHF
2
is used it isomerizes to FCH
2
CH
2
F before reaction with the olefin.
When the addition product (adduct) contains chlorine, the chlorine can be removed by either reaction with HF in the presence of a fluorination catalyst (e.g., Cr
2
O
3
) or by reaction with hydrogen in the presence of a hydrogenation catalyst (e.g., palladium supported on carbon). The adduct is thereby converted from a hydrochlorofluorocarbon to a hydrofluorocarbon.
The temperature employed in the process of the present invention typically ranges from about −10° C. to about 100° C. The preferred temperature range is from about 0° C. to 80° C.
Reaction time is not critical and typically ranges from about 5 seconds to about 24 hours. From about 1 to 16 hours, are usually sufficient.
The pressure employed in the reaction is not critical. The reaction is normally run at pressures in the range of from 0 to 300 psig (101 kPa to 2169 kPa). Autogenous pressures are usually employed; however the pressure should not be allowed to rise above 300 psig when using tetrafluoroethylene because of safety considerations.
Where the reaction conditions are heterogeneous, some degree of agitation is often desirable.
Since the catalysts are water sensitive, reagents and equipment should be dried before use.
The proportion of catalyst to the olefin reactant is typically from about 0.01:1 to about 0.5:1; a range of from 0.1:1 to about 0.5:1 is preferred.
The proportion of saturated compound to olefin is preferably at least about preferably 1:1, when forming RR
1
R
2
CCR
1
R
2
F and preferably at least about 2:1 when forming (FR
1
R
2
CCR
1
R
2
CH
2
)
2
. Of note are embodiments which use saturated compounds as a solvent such that they are present in substantial excess.
The reaction can be done in batch, semi-batch, semi-continuous or continuous modes in one or more reaction vessels. On a laboratory scale, the reaction can be done in shaker tubes, where all reagents are combined before the reaction vessel is sealed and the reaction begun. It can also be done in autoclaves equipped with an agitator. Product(s) may be isolated by standard chemical engineering techniques, e.g., fractional distillation.
Without further elaboration, it is believed that one skilled in the art can, using the description herein, utilize the present invention to its fullest extent. The following specific embodiments are, therefore, to be construed as merely illustrative, and do not constrain the remainder of the disclosure in any way whatsoever.
REFERENCES:
patent: 5162594 (1992-11-01), Krespan
patent: 5227547 (1993-07-01), Ohnishi et al.
patent: 5326913 (1994-07-01), Aoyama et al.
patent: 5608126 (1997-03-01), Morikawa
patent: 5929293 (1999-07-01), Krespan et al.
patent: WO 97/02227 (1997-01-01), None
V.A. Petrov et al., Electrophilic Alkylation of Fluroolefins With 1,1,1-Trifluoroethane,Instituted of Heteroorganic Compounds,9, 1513-1515, Sep., 1980.
Haszeldine et al., Reaction of Hexafluoropropene with Halogenoalkanes,Journal of Fluorine Chemistry,21,No. 2, 253-259, 1982.
G.G. Belen'Kii et al., Chemistry Reviews,Electrophilic Additions,pp. 194-197, vol. 5, 1984.
Belen'Kill Gennadii G.
Petrov Viacheslav A.
Resnick Paul R.
DISA
Siegel Alan
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