Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – Liquid composition
Reexamination Certificate
2000-06-23
2002-05-28
Boyer, Charles (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
Liquid composition
C510S204000, C570S170000, C570S101000, C570S123000, C570S126000, C570S145000, C570S147000, C570S149000
Reexamination Certificate
active
06395700
ABSTRACT:
TECHNICAL FIELD
This invention relates to a process for preparing a compound having at least 4 carbon atoms and a —CH
2
—CHF— group which is useful as a detergent or a solvent.
BACKGROUND ART
In processes for washing various materials in an industrial scale, a solvent composition predominantly comprised of a freon having good incombustibility, low-toxicity and good stability were heretofore widely used. However, freon destroys An ozone layer and invites global warming, and thus, regulations on suppression of the use of freon have been established and the production thereof has been absolutely prohibited all over the world.
Under these circumstances, extensive researches have been made for developing various alternatives for freon. One type of the alternatives for freon is hydrofluorocarbons having no chlorine atom which is a typical example of the ozone layer-destroying factors. It is well known that hydrofluorocarbons have no chlorine atom and are incombustible and stable. It is also known that hydrofluorocarbons exhibit satisfactory washing performance when they are used either alone or in combination with an organic solvent.
It is expected that hydrofluorocarbon compounds having a —CH
2
—CHF— group are new fluorine-containing materials as hydrofluorocarbons having no chlorine atom. The hydrofluorocarbon compounds having a —CH
2
—CHF— group do not destroy the ozone layer and have a short life in the air, and thus, cause the global warming only to a minimum extent. In addition, the hydrofluorocarbon compounds are capable of dissolving contaminants to an appropriate extent, do not affect plastic articles, and exhibit good stability against heat and chemicals and good incombustibility.
As for a process for preparing a chain-like hydrofluorocarbon compound having a —CH
2
—CHF— group, only a process for preparing a hydrofluorocarbon compound having 3 carbon atoms is known. For example, a process for preparing CF
3
CH
2
CHF
2
by hydrogenating CF
3
CH═CF
2
in the presence of a hydrogenation catalyst is described in Japanese Unexamined Patent Publication (hereinafter abbreviated to “JP-A”) No. H8-2594775. A process for preparing CF
3
CH
2
CHF
2
by hydrogenating CF
3
CCl═CF
2
in the presence of a reducing catalyst is described in Japanese Unexamined Patent Publication (hereinafter abbreviated to “JP-A”) No. H8-337542. These processes have problems such that three hydrogen atoms must be introduced in the molecule in two stages and the synthesis of a raw material, CF
3
CCl═CF
2
is troublesome and costly. Therefore, an improved process is desired.
It is known that, in a process for preparing 1,1,2,2,3,3,4,5-octafluorocyolopentane by allowing perfluorocyclopentene to react with hydrogen in the presence of a noble metal catalyst such as, for example, palladium, 1,1,2,2,3,3,4-heptafluorocyclopentane, which is an alicyclic hydrocarbon compound having a —CH
2
—CHF— group and at least 4 carbon atoms, is produced as a side reaction product (Journal of American Chemical Society, p548, 1968). But, there is no description of separating 1,1,2,2,3,3,4-heptafluorocyclopentane from the reaction product. In fact, 1,1,2,2,3,3,4-heptafluorocyclopentane and 1,1,2,2,3,3,4,5-octafluorocyolopentane have boiling points which are very close to each other, and therefore, the former is impossible to separate from the latter by distillation.
A process for producing a compound having at least 4 carbon atoms and a —CH
2
—CHF— group in an industrial scale has not heretofore been proposed.
DISCLOSURE OF THE INVENTION
The object of the present invention is to provide a process for producing a compound having at least 4 carbon atoms and a —CH
2
—CHF— group with a high purity in an industrially advantageous manner.
As a result of extensive researches for achieving the object, the present inventors have found a process whereby the object hydrofluorocarbon compound can be produced at a high purity by utilizing the difference between a chlorine atom and a fluorine atom In reactivity of replacement with hydrogen.
Further, the present inventors have completed an industrially advantageous process for producing the object hydrofluorocarbon compound involving a scheme of reactions which includes a reaction for producing the starting compound need in the above-process.
In one aspect of the present invention, there is provided a process for preparing a compound having at least 4 carbon atoms and represented by the. following formula (3), characterized in that a compound having at least 4 carbon atoms and represented by the following formula (1) is hydrogenated in the presence of a noble metal catalyst in the liquid phase or the vapor phase;
R
1
—C
1
Cl═C
2
F—R
2
(1)
wherein R
1
is a fluorine atom or an alkyl group having 1 to 8 carbon atoms which may be fluorinated, and R
2
is a hydrogen atom, a fluorine atom or an alkyl group having 1 to 8 carbon atoms which may be fluorinated, provided that at least one of R
1
and R
2
is an alkyl group having 1 to 8 carbon atoms which may be fluorinated, and that the sum of carbon atoms in R
1
and R
2
is at least two, and R
1
and R
2
may form together a divalent hydrocarbon group having 2 to 8 carbon atoms represented by the formula —R
1
—R
2
—, in which the entirety or a part of the hydrogen atoms in the hydrocarbon group of formula —R
1
—R
2
— may be fluorinated, and which forms together with C
1
and C
2
an alicyclic compound;
R
3
—C
3
H
2
—C
4
HF—R
4
(3)
wherein R
3
and R
4
are the same as R
1
and R
2
in formula (1), respectively.
In another aspect of the present invention, there is provided a process for preparing a compound having at least 4 carbon atoms and represented by the formula (3), characterized in that a compound having at least 4 carbon atoms and represented by the following formula (4):
R
5
—C
5
Cl═C
6
Cl—R
6
(4)
wherein R
5
and R
6
are the same as R
1
and R
2
in the formula (1), respectively, is allowed to react with a fluorinating agent to give the compound having at least 4 carbon atoms and represented by the formula (1); and then the compound of formula (1) is hydrogenated in the presence of a noble metal catalyst.
BEST MODE FOR CARRYING OUT THE INVENTION
The process of the present invention is concerned with conversion of a compound having at least 4 carbon atoms and a —CCl═CF— group into a compound having at least 4 carbon atoms and a —CH
2
—CHF— group by hydrogenating the former compound in the presence of a noble metal catalyst.
The compound used as the starting material in the process of the present invention is a chain-like compound or preferably an alicyclic compound, which is represented by the following formula (1). The number of carbon atoms in the main chain of the chain-like compound of formula (1) or the cyclic structure of the alicyclic compound of formula (1).
R
1
—C
1
Cl═C
2
F—R
2
(1)
wherein R
1
is a fluorine atom or an alkyl group having 1 to 8 carbon atoms which may be fluorinated, and R
2
is a hydrogen atom, a fluorine atom or an alkyl group having 1 to 8 carbon atoms. A part or the entirety of the alkyl group having 1 to 8 carbon atoms may be fluorinated. However, at least one of R
1
and R
2
is an alkyl group having 1 to 8 carbon atoms which may be fluorinated, and that the sum of carbon atoms in R
1
and R
2
is at least two. R
1
and R
2
may form together a divalent hydrocarbon group having 2 to 8 carbon atoms represented by the formula —R
1
—R
2
—, in which the entirety or a part of the hydrogen atoms in the hydrocarbon group of formula —R
1
—R
2
— may be fluorinated, and which forms together with C
1
and C
2
an alicyclic compound.
Substituents R
1
and R
2
are selected, as mentioned above, from a hydrogen atom, a fluorine atom and an unsubstituted alkyl group having 1 to 8 carbon atoms and an alkyl group having 1 to 8 carbon atoms, a part or the entirety of which is fluorinated, provided that R
1
is not a hydrogen atom. Of these, a fluorine atom and a perfluoroalkyl group having 1 to 8 carbon atoms are preferable.
As specific examples
Sugimoto Tatsuya
Uruma Takashi
Yamada Toshiro
Boyer Charles
Nippon Zeon Co. Ltd.
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