Processes for the preparation of fluorinated acyl fluorides...

Details Processes for the preparation of fluorinated acyl fluorides... Processes for the preparation of fluorinated acyl fluorides...

2003-01-28

2004-06-08

Richter, Johann (Department: 1621)

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

Organic compounds

Carboxylic halides

C562S840000, C562S849000, C562S851000, C568S592000, C568S591000, C568S594000, C568S596000, C568S598000, C570S140000, C570S142000

Reexamination Certificate

active

06747174

ABSTRACT:

TECHNICAL FIELD
The present invention relates to a process for preparing a fluorinated acyl fluoride and a process for preparing a fluorinated vinyl ether from the fluorinated acyl fluoride.
BACKGROUND ART
As techniques for fluorinating compounds containing C—H bonds by converting all the C—H bonds to C—F bonds, use of cobalt trifluoride, direct fluorination with fluorine gas and electrochemical fluorination using hydrogen fluoride electrolytically obtained from electrolytic cells as the fluorine source (hereinafter referred to as ECF) have been known.
These fluorination techniques are applied to give various useful fluorinated compounds. As an example of production of fluorinated acyl fluorides highly useful as intermediates of fluorinated compounds by ECF, production of perfluoroacyl fluorides by ECF of partially fluorinated esters obtained from primary or secondary alcohols and fluorinated acyl fluorides followed by dissociation of the resulting perfluoroesters is disclosed (U.S. Pat. No. 3,900,372).
Liquid phase fluorination in which a hydrogen-containing organic compound dispersed or dissolved in a perhalogenated liquid medium is fluorinated with fluorine gas blown into the medium is disclosed as a fluorination method using direct fluorination (U.S. Pat. No. 5,093,432 and JP-A-4-500520).
However, use of ether oxygen-containing compounds as the substrate in synthesis of fluorinated acyl fluorides by ECF has a problem of very low yields due to cleavage of the C—O bonds. Use of ether oxygen-containing compounds containing no fluorine atoms as the substrate in liquid phase fluorination also has problems of poor yields of fluorinated products and poor volume efficiency.
The present invention aims to solve the problems with the prior art and provides a production process which permits efficient fluorination, even if the substrate is an ether oxygen-containing compound, with a high yield of fluorinated acyl fluorides. The present invention also provides a process for industrially preparing fluorinated acyl fluorides by employing ether oxygen-containing compounds having a specific structure. Further, the present invention provides a process for preparing fluorinated vinyl ethers useful as starting materials for fluororesins.
DISCLOSURE OF THE INVENTION
The present inventors have found out that use of compounds having a fluorine content at or higher than a certain level in liquid phase fluorination as a starting material to produce fluorinated acyl fluorides makes it possible to carry out fluorination at high yield with high volume efficiency, even if the starting material is an ether oxygen-containing compound. They have also found out that pyrolysis of the fluorinated acyl fluoride obtained by the process of the present invention gives fluorinated vinyl ethers useful as starting materials for production of fluororesins.
Namely, the present invention provides a process for preparing a fluorinated acyl fluoride represented by the following formula (3), which comprises reacting a compound represented by the following formula (1) having a fluorine content of 30 mass % or above with fluorine in a liquid phase to form a compound represented by the following formula (2) and then dissociating the ester bond in the compound represented by the formula (2):
wherein each of R
A
and R
B
, which may be the same or different, is a monovalent saturated hydrocarbon group, a halogenated monovalent saturated hydrocarbon group, a hetero atom-containing monovalent saturated hydrocarbon group or a halogenated (hetero atom-containing monovalent saturated hydrocarbon) group, each of R
C
and R
D
, which may be the same or different, is a hydrogen atom, a halogen atom, a monovalent saturated hydrocarbon group, a halogenated monovalent saturated hydrocarbon group, a hetero atom-containing monovalent saturated hydrocarbon group or a halogenated (hetero atom-containing monovalent saturated hydrocarbon) group,
each of X
1
, X
2
, X
3
, X
4
, X
5
and X
6
, which may be the same or different, is a hydrogen atom or a fluorine atom, provided that at least one of R
A
, R
B
, R
C
, R
D
, X
1
, X
2
, X
3
, X
4
, X
5
and X
6
is a fluorine-containing group or a fluorine atom,
R
AF
corresponds to R
A
, R
BF
corresponds to R
B
, R
CF
corresponds to R
C
, R
DF
corresponds to R
D
, and when R
A
, R
B
, R
C
and R
D
are hydrogen-containing groups, R
AF
, R
BF
, R
CF
and R
DF
are groups derived respectively from R
A
, R
B
, R
C
and R
D
by replacing substantially all the hydrogen atoms by fluorine atoms, and when R
A
, R
B
, R
C
and R
D
are groups containing no hydrogen atoms, R
AF
, R
BF
, R
CF
and R
DF
are the same as R
A
, R
B
, R
C
and R
D
, respectively,
the combination of R
A
and R
B
and the combination of R
C
and R
D
may form bivalent groups selected from bivalent saturated hydrocarbon groups, halogenated bivalent saturated hydrocarbon groups, hetero atom-containing bivalent saturated hydrocarbon groups and halogenated (hetero atom-containing bivalent saturated hydrocarbon) groups, respectively, the combination of R
AF
and R
BF
forms a bivalent group corresponding to a bivalent group formed by the combination of R
A
and R
B
, and the combination of R
CF
and R
DF
forms a bivalent group corresponding to a bivalent group formed by the combination of R
C
and R
D
, provided that when the combination of R
A
and R
B
and the combination of R
C
and R
D
form hydrogen-containing bivalent groups, the bivalent groups formed by the combination of R
AF
and R
BF
and the combination of R
CF
and R
DF
are groups derived from the hydrogen-containing bivalent groups by replacing substantially all the hydrogen atoms by fluorine atoms, and when the combination of R
A
and R
B
and the combination of R
C
and R
D
form bivalent groups containing no hydrogen atoms, the bivalent groups formed by the combination of R
AF
and R
BF
and the combination of R
CF
and R
DF
are the same as the bivalent groups containing no hydrogen atoms.
The present invention also provides a process for preparing a fluorinated acyl fluoride represented by the following formula (3), which comprises reacting a compound represented by the following formula (5) with a compound represented by the following formula (7) to form a compound represented by the following formula (8) having a fluorine content of 30 mass % or above, fluorinating the compound represented by the formula (8) in a liquid phase to form a compound represented by the following formula (9) and dissociating the ester bond in the compound represented by the formula (9):
wherein each of R
A
and R
B
, which may be the same or different, is a monovalent saturated hydrocarbon group, a halogenated monovalent saturated hydrocarbon group, a hetero atom-containing monovalent saturated hydrocarbon group or a halogenated (hetero atom-containing monovalent saturated hydrocarbon) group, each of X
1
, X
2
and X
3
, which may be the same or different, is a hydrogen atom or a fluorine atom, provided that at least one of R
A
, R
B
, X
1
, X
2
and X
3
is a fluorine-containing group or a fluorine atom,
R
AF
corresponds to R
A
, R
BF
corresponds to R
B
, and when R
A
and R
B
are hydrogen-containing groups, R
AF
and R
BF
are groups derived respectively from R
A
and R
B
by replacing substantially all the hydrogen atoms by fluorine atoms, and when R
A
are R
B
are groups containing no hydrogen atoms, R
AF
and R
BF
are the same as R
A
and R
B
, respectively,
the combination of R
A
and R
B
may form a bivalent group selected from a bivalent saturated hydrocarbon group, a halogenated bivalent saturated hydrocarbon group, a hetero atom-containing bivalent saturated hydrocarbon group and a halogenated (hetero atom-containing bivalent saturated hydrocarbon) group, provided that when the combination of R
A
and R
B
forms a hydrogen-containing bivalent group, the bivalent group formed by the combination of R
AF
and R
BF
is a group derived from the hydrogen-containing bivalent group by replacing substantially all the hydrogen atoms by fluorine atoms, and when the combination

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