Processes for the production of hexafluoropropene and...

Details Processes for the production of hexafluoropropene and... Processes for the production of hexafluoropropene and...

2000-11-27

2001-12-11

Siegel, Alan (Department: 1621)

Organic compounds -- part of the class 532-570 series

Organic compounds

Halogen containing

C570S164000, C570S166000, C570S167000, C570S168000, C570S169000

Reexamination Certificate

active

06329559

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to the synthesis of hexafluoropropene, and optionally other halogenated hydrocarbons containing fluorine, especially 1,1,1,3,3,3-hexafluoropropane. and 1,1,1,2,3,3-hexafluoropropane.
BACKGROUND
Commercial methods for the preparation of hexafluoropropene (CF
3
CF═CF
2
or HFP), a fluoromonomer, typically involve temperatures greater than 600° C. The high reaction temperatures lead to the formation of perfluoroisobutylene, an extremely toxic compound which is costly to remove and destroy (e.a., see European Patent Application No. 002,098). Processes for the manufacture of HFP at lower temperatures based on the use of acyclic three-carbon hydrocarbons or partially halogenated three-carbon hydrocarbons are disclosed in U.S. Pat. Nos. 5,043,491, 5,057,634 and 5,068,472.
1,1,1,2,3,3,3-Heptafluoropropane (CF
3
CHFCF
3
or HFC-227ea), a fire extinguishant, can be prepared by the reaction of HF with HFP in contact with activated carbon (e.g., see British Patent Specification No. GB 902,590). The manufacture of HFC-227ea in this instance is tied to the availability HFP.
U.S. Pat. No. 5.573.654 reports the preparation of 1,1,1,3,3,3-hexafluoropropane (CF
3
CH
2
CF
3
or HFC-236fa), a fire extinguishant and refrigerant. by the reaction of extremely toxic perfluoroisobutylene with triethylamine and water. 1,1,1,2,3,3-Hexafluoropropane (CF
3
CHFCHF
2
or HFC-236ea) is also a refrigerant.
There is a need for alternative methods of manufacturing HFP and other halogenated hydrocarbons containing fluorine. such as the fluorinated propanes HFC-236fa and HFC-236ea.
SUMMARY OF THE INVENTION
This invention provides a process for the manufacture of CF
3
CF═CF
2
, and optionally at least one compound selected from CF
3
CH
2
CF
3
and CF
3
CHFCHF
2
. The process comprises (a) contacting a reactor feed comprising a precursor stream of at least one compound selected from halogenated propanes of the formula CX
3
CH
2
CH
y
X
(3−y)
and halogenated propenes of the formula CX
3
CH═CH
y
X
(2−y)
, where each X is independently selected from Cl and F and y is 0, 1 or 2, provided that the average fluorine content of said precursor stream is no more than 5 fluorine substituents per molecule, with HF and Cl
2
in a chlorofluorination reaction zone containing a fluorination catalyst and operating at a temperature between about 150° C. and 400° C. to produce a reaction zone effluent comprising HF, HCl and a mixture of reaction products of said precursor stream which contains at least one compound of the formula C
3
Cl
2
F
6
including CClF
2
CClFCF
3
and at least one compound of the formula C
3
HClF
6
including CHF
2
CClFCF
3
and has an average fluorine content which is at least one fluorine substituent per molecule more than the average fluorine content of the precursor stream, (b) distilling the reaction zone effluent of (a) to produce (i) a low-boiling component comprising HCl and when they are present in said reaction zone effluent, C
3
F
8
, C
3
ClF
7
and C
3
HF
7
, (ii) a hydrogenation feed component comprising at least one compound of the formula C
3
Cl
2
F
6
including CClF
2
CCIFCF
3
and at least one compound of the formula C
3
HClF
6
including CHF
2
CClFCF
3
, and (iii) an underfluorinated component comprising halogenated propanes containing at least one chlorine substituent and from one to five fluorine substituents; (c) reacting the CClF
2
CClFCF
3
and CHF
2
CClFCF
3
of hydrogenation feed component (ii) with hydrogen to produce a mixture comprising CF
3
CF═CF
2
and CF
3
CHFCHF
2
; (d) recovering the CF
3
CF═CF. from the product mixture of (c); and (e) returning the underfluorinated component (iii) to the chlorofluorination reaction zone.


REFERENCES:
patent: 2576823 (1951-11-01), Benning
patent: 5043491 (1991-08-01), Webster et al.
patent: 5057634 (1991-10-01), Webster et al.
patent: 5068472 (1991-11-01), Webster et al.
patent: 5523501 (1996-04-01), Kellner et al.
patent: 5573654 (1996-11-01), Cheurkov et al.
patent: 1237084 (1967-03-01), None
patent: 002098 (1979-05-01), None
patent: 434 407A (1991-06-01), None
patent: 0 434 409 A (1991-06-01), None
patent: 821 211A (1959-10-01), None
patent: 902590 (1962-08-01), None
patent: 938 070 A (1963-09-01), None
patent: 2 313 118 A (1997-11-01), None
patent: WO 90 08748 A (1990-08-01), None
patent: WO 91 05752 A (1991-05-01), None
patent: WO 99/62849 (1999-12-01), None
U.S. application No. 09/701,449, Sievert et al., see IDS.
J. Kricala et al., J. Fluorine, 43 (1989), pp. 155-175.

Affiliated with

Also associated with

Rating

Processes for the production of hexafluoropropene and... does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Processes for the production of hexafluoropropene and..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Processes for the production of hexafluoropropene and... will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2581225