Fluorinated, saturated hydrocarbons

Details Fluorinated, saturated hydrocarbons Fluorinated, saturated hydrocarbons

2000-02-03

2002-06-11

Padmanabhan, Sreeni (Department: 1621)

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

Organic compounds

Halogen containing

C570S175000, C570S176000, C570S186000

Reexamination Certificate

active

06403846

ABSTRACT:

This application is a 371 application of PCT/JP98/02157 filed May 15, 1998.
1. Technical Field
The invention of this application relates to fluorinated saturated hydrocarbons. More specifically, the invention of this application relates to fluorinated saturated hydrocarbons, which are useful as substitute compounds of CFC (chlorofluorocarbon), HCFC (hydrochlorofluorocarbon), PFC (perfluoro compound), and chlorine-type solvents, which have been widely used as detergents, foaming agents, refrigerants, and the like. The compounds described in the invention of this application have less influence on the global environment, show less toxicity to human bodies, and are chemically stable. The invention of this application also relates to a process for producing the above compounds, and compositions thereof.
2. Background of the Invention
As an industrial method for washing various materials, products composed mainly of CFC 113 or 1,1,1-trichloroethane which are incombustible, low in toxicity, and excellent in stability have been widely used. However, it has been identified that various CFCs, 1,1,1-trichloroethane, carbon tetrachloride and the like destroy the stratospheric ozone layer. In view of the protection of the ozone layer, the production of CFC 113, 1,1,1-trichloroethane and the like has been completely abolished worldwide since the end of 1995, and regulations have been set on their use.
As substitutes of CFC 113 and the like, hydrochlorofluorocarbons such as HCFC 225 and HCFC 141b have been proposed. However, since these compounds are, though slightly, also destructive to the ozone layer, a time limit has been set in their use. Further, chlorinated solvents such as methylene chloride, trichloroethylene, perchloroethylene and the like have also been problematic regarding their safety (carcinogenicity and intoxication), and various regulations have been already set or are being studied.
Further, various fluorine type compounds which do not contain chlorine atoms that cause the destruction of the ozone layer, and can maintain non-combustibility, safety and such merits as mentioned above, have been synthesized. For example, a product composed mainly of perfluorocarbons such as perfluoro-n-heptane (WO 92-03205 and the like), a product composed mainly of acyclic hydrofluorocarbon (WO 95-06693, JP-W-6-501949 and the like), a product composed mainly of specific acyclic hydrofluorocarbons (WO 95-05448) and the like are mentioned.
These perfluorocarbons and hydrofluorocarbons were preferable because there is no worry for the destruction of the ozone layer and detergency with good finish is exhibited by using the same as such or along with organic solvents. However, these compounds each had problems that needed to be improved. For example, perfluorocarbons have high global warming coefficient, and there is fear that new problems on the preservation of the global environment might occur. Further, with respect to acyclic or cyclic hydrofluorocarbons, various structures have been proposed, but have problems in their structures. For example, compounds having —CH
2
CH
2
— bonds, with 4 or 5 carbon atoms, and a boiling point in the region suitable for detergents or solvents, are combustible.
Accordingly, an object of the invention of this application is to provide, upon improving the defects of such hydrofluorocarbons known so far, fluorinated saturated hydrocarbons which are excellent as detergents, and excellent in their non-combustibility and their stability in the presence of water, which can construct now detergents and the like, and are easy to produce, a process for producing the same, and compositions thereof.
DISCLOSURE OF THE INVENTION
The invention of this application is to provide, as a product to solve the above-mentioned problems, a composition comprising less than 95 mol % of a trihydrofluorinated saturated hydrocarbon (A) represented by the following formula (I)
Rf
1
—R
1
—Rf
2
  (I)
(wherein R
1
represents a carbon chain in which CHF and CH
2
are bound, and Rf
1
and Rf
2
are bound to each other to form a ring by a perfluoroalkylene chain of 2 to 4 carbon atoms)
and the balance of a tetrahydrofluorinated saturated hydrocarbon (B) having the same number of carbons and the same carbon structure as the trihydrofluorinated saturated hydrocarbon (A), as represented by the following formula (II)
Rf
1
—R
2
—Rf
2
  (II)
(wherein R
2
represents a carbon chain in which CH
2
and CH
2
are bound, and Rf
1
and Rf
2
are as defined above).
The reason that the proportions of the fluorinated saturated hydrocarbons (A) and (B) are as mentioned above is that according to the invention of this application, the fluorinated hydrocarbon of this invention is provided by a specific process described later in this application, and as a content of a detergent or the like, the fluorinated saturated hydrocarbon of this invention is introduced as a novel product.
The proportion of the trihydrofluorinated hydrocarbon (A) is less than 95 mol %, generally 10 mol % or more, preferably 50 mol % or more, more preferably 70 mol % or more, further preferably 80 mol % or more. The higher the proportion of the trihydrofluorinated hydrocarbon (A), the more the fluorinated saturated hydrocarbon of this invention becomes non-combustible.
The fluorinated saturated hydrocarbons (A) and (B) are cyclic. The number of carbon atoms in the fluorinated hydrocarbons is between 4 and 6, and most preferably 5. Specific compounds of the fluorinated saturated hydrocarbon (A) having the trihydrofluorocarbon chain include 1,1,2,2,3-pentafluorocyclobutane, 1,1,2,2,3,3,4-heptafluorocyclopentane, and 1,1,2,2,3,3,4,4,5-nonafluorocyclohexane, of which 1,1,2,2,3,3,4-heptafluorocyclopentane (HFCPA) is mentioned as especially preferable.
In this invention, the tetrahydrofluorinated saturated hydrocarbon (B) having the same number of carbons and the same carbon structure as the trihydrofluorinated saturated hydrocarbon (A) co-exists. For example, it is shown that 1,1,2,2,3,3-hexafluorocyclopentane co-exists with 1,1,2,2,3,3,4-heptafluorocyclopentane (HFCPA) mentioned above.
The composition of this invention is excellent in detergency, is highly non-combustible, is excellent in stability under the presence of water, and the production thereof is easy.
Thus, the process for producing the composition of the invention of this application is described.
The process for producing the composition of this invention, which contains the fluorinated hydrocarbon compounds represented by formulas (III) and (IV) such as the fluorinated hydrocarbons (A) and (B) mentioned above, is quite unique. For example, the formation of 1H,1H,2H-heptafluorocyclopentane or the like which is a trihydro compound has been so far observed during the reaction of hydrogenating perfluorocyclopentene in the presence of palladium-alumina, and it is disclosed that the main product of this reaction is 1H,2H-octafluorocyclopentane (J. Chem. Soc., C.548 (1968)). Only 10% of heptafluorocyclopentane (HFCPA) having a trihydrofluorocarbon chain was reportedly obtained, and further, was difficult to separate from octafluorocyclopentane (OFCPA) by distillation.
Moreover, according to the official gazette of JP-B-5-148171, when 1,1,1,2,2,3,4,5,5,5-decafluoropentane is produced by hydrogenating decafluoropentene-2 using palladium supported on carbon, alumina, or the like as a catalyst, by products such as 1,1,1,2,2,4,5,5,5-nonafluoropentane, 1,1,1,2,2,3,5,5,5-nonafluoropentane, 1,1,1,2,2,5,5,5-octafluoropentane and the like were produced in large amounts. However, it was reportedly difficult to separate these by-products from the desired product by the process of distillation.
That is, providing fluorinated saturated hydrocarbons containing heptafluorocyclopentane (HFCPA) and the like which contain trihydrofluorocarbon chains in high proportions has not been industrially realized so far.
Meanwhile, in the process of this invention, a cyclic fluorinated, unsaturated hydrocarbon having the unsaturated fluorocarbon chain as represented by formula (V) is used as a su

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