Process for the manufacture of fluorine-substituted...

Details Process for the manufacture of fluorine-substituted... Process for the manufacture of fluorine-substituted...

1999-08-06

2001-06-05

Killos, Paul J. (Department: 1623)

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

Organic compounds

Halogen containing

C556S013000, C558S460000, C558S461000, C560S227000

Reexamination Certificate

active

06242658

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to processes for producing selected substituted hydrocarbons containing fluorine, and more particularly to processes involving hydrogenolysis for producing substituted hydrocarbons containing fluorine and hydrogen and compositions provided in such processes.
BACKGROUND OF THE INVENTION
Chlorofluorocarbons (CFCs, i.e., compounds containing only carbon, fluorine and chlorine) have been used for many years as refrigerants, heat transfer media, foam expansion agents, aerosol propellants, solvents and power cycle working fluids. For example, various CFC solvents have been used as cleaning liquids for the removal of contaminants from contaminated articles and materials. Certain fluorine-containing organic compounds such as 1,1,2-trichloro-1,2,2-trifluoroethane (CFC-113) have been reported as useful for this purpose, particularly with regard to cleaning organic polymers and plastics which may be sensitive to other more common and more powerful solvents such as trichloroethylene or perchloroethylene. Recently, however, there have been efforts to reduce the use of certain chlorofluorocarbon compounds such as CFC-113 because of a concern over their potential to deplete ozone, and to thereby affect the layer of ozone that is considered important in protecting the earth's surface from ultraviolet radiation. Consequently, there is a worldwide effort to find alternative compounds which contain fewer or preferably no chlorine substituents.
Boiling point, flammability and solvent power can often be adjusted by preparing mixtures of solvents. For example, certain mixtures of 1,1,2-trichloro-1,2,2-trifluoroethane with other solvents (e.g., isopropanol and nitromethane) have been reported as useful in removing contaminants which are not removed by 1,1,2-trichloro-1,2,2-trifluoroethane alone, and in cleaning articles such as electronic circuit boards where the requirements for a cleaning solvent are relatively stringent (i.e., it is generally desirable in circuit board cleaning to use solvents which have low boiling points, are non-flammable, have low toxicity, and have high solvent power so that flux such as rosin and flux residues which result from soldering electronic components to the circuit board can be removed without damage to the circuit board substrate).
While boiling point, flammability, and solvent power can often be adjusted by preparing mixtures of solvents, the utility of the resulting mixtures can be limited for certain applications because the mixtures fractionate to an undesirable degree during use. Mixtures can also fractionate during recovery, making it more difficult to recover a solvent mixture with the original composition. Azeotropic compositions, with their constant boiling and constant composition characteristics, are thus considered particularly useful.
The properties of halogenated hydrocarbons can be influenced by the arrangement of the halogens (and hydrogen, when present) on the carbon framework. One of the challenges in preparing compounds containing fluorine and hydrogen has been achieving the desired arrangement of such substituents.
One arrangement involves providing a hydrogen on different carbons spaced a selected distance from one another along a carbon chain. For example, it can be desirable to provide a hydrogen substituent on each of two carbon atoms which are separated from one another by a chain of two other carbon atoms. 1,1,2,2,3,3,4,4-Octafluorobutane (HFC-338pcc) is such a compound. HFC-338pcc forms useful blends, and particularly azeotropes, with solvents such as alcohols, ketones, and other halogenated solvents to form compositions useful for cleaning surfaces, especially electronic components as disclosed in U.S. Pat. No. 5,250,208, U.S. Pat. No. 5,221,493, and U.S. Pat. No. 5,194,170. There is a need for non-chlorinated solvents like HFC-338pcc (which have little effect on the ozone layer) as replacements for more chlorinated solvents such as CFC-113. There is also a need for processes for effectively producing compounds such as HFC-338pcc.
U.S. patent application Ser. No. 08/315,025 (the priority document for PCT International Publication No. WO 96/10002), which is incorporated herein by reference, discloses a process for the preparation of product compounds of the formula HC(R
1
)
2
C(R
1
)
2
C(R
2
)
2
C(R
2
)
2
H (e.g., CHF
2
CF
2
CF
2
CHF
2
, HFC-338pcc) by reaction of a metallacycle of the formula
with hydrogen.
SUMMARY OF THE INVENTION
The present invention provides an advantageous process for the manufacture of a product compound of the formula HC(R
1
)
2
C(R
1
)
2
C(R
2
)
2
C(R
2
)
2
H wherein each R
1
is independently selected from the group consisting of H, F, Cl, CN, R, OR, CO
2
R, C(O)R, OC(O)R, R
f
, OR
f
, CO
2
R
f
C(O)R
f
and OC(O)R
f
, where R is a hydrocarbyl group and R
f
is a C
1
to C
10
polyfluoroalkyl group, provided that at least one R
1
is F, and wherein each R
2
is independently selected from the group consisting of H, F, Cl, CN, R, OR, CO
2
R, C(O)R, OC(O)R, R
f
, OR
f
, CO
2
R
f
C(O)R
f
, OC(O)R
f
and difunctional linkages where an R
2
on each of two adjacent carbon atoms together form a link selected from the group consisting of —CH
2
CH
2
CH
2
—, —CH
2
CH
2
CH
2
CH
2
—, —CH
2
CH
2
CH(CH
3
)—, —CH
2
CH(CH
3
)CH
2
—, —C(O)OC(O)—, and norborndiyl.
The process of this invention comprises reacting a metallacycle of the formula
(i.e., L
m
Ni(1,4—C(R
1
)
2
C(R
1
)
2
C(R
2
)
2
C(R
2
)
2
—)) wherein R
1
and R
2
are as defined above, and wherein each L is a ligand independently selected from the group consisting of a phosphite of the formula P(OR
3
)
3
,
and (R
3
O)
2
POP(OR
3
)
2
; each R
3
is independently selected the group consisting of CH
2
CR
6
R
7
R
8
; each R
6
, R
7
, and R
8
is independently selected from the group consisting of C
1
to C
10
alkyl, benzyl, phenyl, and phenyl substituted with one or more R
10
, provided that two of R
6
, R
7
, and R
8
in a R
3
may be co-joined to provide a C
5
to C
7
cycloalkane ring, and that all three of R
6
, R
7
, and R
8
in a R
3
may together form an adamantyl group; each R
10
is independently selected from the group consisting of C
1
to C
4
alkyl, F, Cl, Br, N(R
9
)
2
, OR
9
and CO
2
R
9
; each R
9
is independently selected from the group consisting of H and C
1
to C
4
alkyl; each R
4
is independently selected from the group consisting of C
1
to C
4
alkyl; and m is an integer from 1 to 2, with hydrogen.
This invention also provides metallacyclic compounds, for example, a compound of the formula L
2
Ni(1,4—CR
1
2
CR
1
2
CR
2
2
CR
2
2
—) wherein L, R
1
and R
2
are as defined above.
This invention also provides nickel compounds, for example, a compound of the formula L
4
Ni wherein L is as defined above.
DETAILED DESCRIPTION
A metallacycle is a cyclic carbon compound where one or more carbons are replaced by a transition metal. Applicants have discovered that certain fluorine-containing nickel metallacycles can be advantageously reacted with hydrogen to add hydrogen to each of two carbon atoms separated from one another by a chain of two other carbon atoms and produce selected halogenated hydrocarbons containing fluorine and hydrogen.
An olefinic compound of the formula (R
1
)
2
C═C(R
1
)
2
and another or the same olefinic compound of the formula (R
2
)
2
C═C (R
2
)
2
may be reacted in the liquid phase with a nickel complex of the formula NiL
n
where n is an integer from 2 to 4 to form a metallacycle of the structure shown in the Summary of the Invention. In accordance with this invention, the metallacycle may be reacted in the liquid phase with hydrogen to produce an organic compound of the formula, HC(R
1
)
2
C(R
1
)
2
C(R
2
)
2
C(R
2
)
2
H. The nickel fragment NiL
m
released by the hydrogenation reaction, which under the reaction conditions may revert partly or completely to NiL
n
, typically may be converted back to the metallacyclic compound, NiL
m
(1,4—C(R
1
)
2
C(R
1
)
2
C(R
2
)
2
C(R
2
)
2
—), by subsequent reaction with the olefinic compounds (R
1
)
2
C═C(R
1
)
2
and

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