Lewis acid catalyst composition Number:7,084,088 from the United States Patent and Trademark Office (PTO) owispatent

Title: Lewis acid catalyst composition

Abstract: A Lewis acid catalyst composition comprising a specific mixed medium and a Lewis acid catalyst, wherein the Lewis acid catalyst is at least one compound selected from the group consisting of compounds respectively represented by the following formulae (1) and (2): [(R.sub.f.sup.1SO.sub.2)(R.sub.f.sup.2SO.sub.2)N].sub.nM, (1) and [(R.sub.f.sup.1SO.sub.2)(R.sub.f.sup.2SO.sub.2)(R.sub.f.sup.3SO.sub.2)C].- sub.nM. (2) A method for continuously performing a reaction which proceeds in the presence of the above-mentioned Lewis acid catalyst by using a specific mixed medium and the above-mentioned Lewis acid catalyst. A novel Lewis acid catalyst.

Patent Number: 7,084,088 Issued on 08/01/2006 to Nishikido,   et al.

---

Inventors:	Nishikido; Joji (Tokyo, JP); Yoshida; Akihiro (Tokyo, JP); Ikeda; Masanori (Fuji, JP)
Assignee:	The Noguchi Institute (Tokyo, JP) Asahi Kasei Kabushiki Kaisha (Osaka, JP)
Appl. No.:	10/491,532
Filed:	December 19, 2002
PCT Filed:	December 19, 2002
PCT No.:	PCT/JP02/13302
371(c)(1),(2),(4) Date:	April 02, 2004
PCT Pub. No.:	WO03/051511
PCT Pub. Date:	June 26, 2003

---

Foreign Application Priority Data

---

Dec 19, 2001 [JP]			2001-386050
Oct 03, 2002 [JP]			2002-290745

Current U.S. Class:	502/155 ; 502/103; 502/152
Current International Class:	B01J 31/00 (20060101)
Field of Search:	502/155,152,103

---

References Cited [Referenced By]

---

U.S. Patent Documents

	5463082		October 1995		Horvath et al.
	6245706		June 2001		Hlatky
	6436866		August 2002		Nishikido et al.
	6610789		August 2003		Watakabe et al.
	6617474		September 2003		Favre et al.
	6727329		April 2004		Vogel

Foreign Patent Documents

	2001-39896		Feb., 2001		JP
	2001-190962		Jul., 2001		JP
	2002-320858		Nov., 2002		JP

Other References

International Search Report and English translation thereof. cited by othe- r . Mikami et al., Lewis acid catalysis by lanthanide complexes with tris (perfluorooctane--sulfonyl) methide ponytails in fluorous recyclable phase, Tetrahedron Letters, Jan. 18, 2001, vol. 42, No. 2, pp. 289 to 292. cited by other . Nishikido et al., The Chemical Society of Japan Koen Yokoshu, Mar. 28, 2001, vol. 79, No. 2, p. 1144. cited by other . Nishikido et al., The Chemical Society of Japan Koen Yokoshu, Sep. 20, 2001 vol. 80, p. 20. cited by other . Kaku et al., The Chemical Society of Japan Koen Yokoshu, Mar. 26, 2002, vol. 81, No. 2, p. 1193. cited by other . Mikami et al., Tetrahedron, May 13, 2002, vol. 58, No. 20, pp. 4015 to 4021. cited by other . Mikami et al., Chemistry, Jul. 2, 2002, vol. 57, No. 7, pp. 22-26. cited by other.

Primary Examiner: Lorengo; J. A.
Assistant Examiner: Brown; Jennine
Attorney, Agent or Firm: Birch, Stewart, Kolasch & Birch, LLP

---

Claims

---

The invention claimed is:

1. A Lewis acid catalyst composition comprising a mixed medium and a Lewis acid catalyst, said mixed medium comprising (A) a fluorinated compound medium and (B) a non-fluorinated compound medium which can be phase-separated from the fluorinated compound medium (A), said Lewis acid catalyst being at least one compound selected from the group consisting of compounds respectively represented by the following formulae (1) and (2): [(R.sub.f.sup.1SO.sub.2)(R.sub.f.sup.2SO.sub.2)N].sub.nM (1), and [(R.sub.f.sup.1SO.sub.2)(R.sub.f.sup.2SO.sub.2)(R.sub.f.sup.3SO.sub.2)C].- sub.nM (2) wherein: each of R.sub.f.sup.1 to R.sub.f.sup.3 independently represents a substituent (.alpha.) selected from the group consisting of a perfluorinated, saturated or unsaturated C.sub.7 C.sub.20 hydrocarbon group containing in the skeleton thereof at least one heteroatom selected from the group consisting of a nitrogen atom and an oxygen atom and a partially substituted derivative thereof, or a substituent (.beta.) selected from the group consisting of a perfluorinated, saturated or unsaturated C.sub.1 C.sub.16 hydrocarbon group containing no heteroatom and a partially substituted derivative thereof, provided that, in formula (1) above, at least one member selected from the group consisting of R.sub.f.sup.1 and R.sub.f.sup.2 is said substituent (.alpha.) and, in formula (2) above, at least one member selected from the group consisting of R.sub.f.sup.1 to R.sub.f.sup.3 is said substituent (.alpha.), wherein, in said partially substituted derivative in the definition of each of said substituents (.alpha.) and (.beta.), a part of the fluorine atoms in said perfluorinated hydrocarbon group is replaced by at least one member selected from the group consisting of a hydrogen atom and a halogen atom exclusive of a fluorine atom, provided that, in each of said substituents (.alpha.) and (.beta.), a part of the fluorine atoms bonded to a carbon atom directly bonded to the --SO.sub.2 group is not replaced by a hydrogen atom; M represents an atom selected from the group consisting of transition metals including rare earth metals, gallium, indium, thallium, silicon, germanium, tin, lead, antimony and bismuth; and n is an integer equivalent to the valence of M.

2. The Lewis acid catalyst composition according to claim 1, wherein each of R.sub.f.sup.1 to R.sub.f.sup.3 in said formulae (1) and (2) independently represents substituent (.alpha.) which is represented by any one of the following formulae (3) and (4): CF.sub.2X.sup.1CFX.sup.2--[OCF.sub.2CF(CF.sub.3)].sub.t--O--[CF.sub.2].su- b.u-- (3), and CF.sub.2.dbd.CF--[OCF.sub.2CF(CF.sub.3)].sub.t--O--[CF.sub.2].sub.u-- (4) wherein, each of X.sup.1 and X.sup.2 independently represents an atom selected from the group consisting of a halogen atom and a hydrogen atom; t is an integer of from 1 to 4; and u is an integer of from 1 to 4.

3. A method for continuously performing a reaction which proceeds in the presence of a Lewis acid catalyst, which comprises: providing a reaction zone containing a Lewis acid catalyst and a fluorinated compound medium (A), wherein said Lewis acid catalyst is at least one compound selected from the group consisting of compounds respectively represented by the following formulae (1) and (2): [(R.sub.f.sup.1SO.sub.2)(R.sub.f.sup.2SO.sub.2)N].sub.nM (1), and [(R.sub.f.sup.1SO.sub.2)(R.sub.f.sup.2SO.sub.2)(R.sub.f.sup.3SO.sub.2)C].- sub.nM (2) wherein: each of R.sub.f.sup.1 to R.sub.f.sup.3 independently represents a substituent (.alpha.) selected from the group consisting of a perfluorinated, saturated or unsaturated C.sub.7 C.sub.20 hydrocarbon group containing in the skeleton thereof at least one heteroatom selected from the group consisting of a nitrogen atom and an oxygen atom and a partially substituted derivative thereof, or a substituent (.beta.) selected from the group consisting of a perfluorinated, saturated or unsaturated C.sub.1 C.sub.16 hydrocarbon group containing no heteroatom and a partially substituted derivative thereof, provided that, in formula (1) above, at least one member selected from the group consisting of R.sub.f.sup.1 and R.sub.f.sup.2 is said substituent (.alpha.) and, in formula (2) above, at least one member selected from the group consisting of R.sub.f.sup.1 to R.sub.f.sup.3 is said substituent (.alpha.), wherein, in said partially substituted derivative in the definition of each of said substituents (.alpha.) and (.beta.), a part of the fluorine atoms in said perfluorinated hydrocarbon group is replaced by at least one member selected from the group consisting of a hydrogen atom and a halogen atom exclusive of a fluorine atom, provided that, in each of said substituents (.alpha.) and (.beta.), a part of the fluorine atoms bonded to a carbon atom directly bonded to the --SO.sub.2 group is not replaced by a hydrogen atom, M represents an atom selected from the group consisting of transition metals including rare earth metals, gallium, indium, thallium, silicon, germanium, tin, lead, antimony and bismuth, and n is an integer equivalent to the valence of M; and continuously feeding a mixture of at least one reactant and a non-fluorinated compound medium (B) which can be phase-separated from said fluorinated compound medium (A) and mixing said fluorinated compound medium (A) containing said Lewis acid catalyst and said non-fluorinated compound medium (B) containing at least one reactant to thereby effect a reaction in the presence of said Lewis acid catalyst and obtain a reaction mixture comprising said flourinated compound medium (A), said non-fluorinated compound medium (B), said Lewis acid catalyst and a reaction product, while continuously separating said reaction mixture into a reaction-formed non-fluorinated compound medium (B) phase containing said reaction product and a reaction-formed fluorinated compound medium (A) phase containing said Lewis acid catalyst in a phase separation zone which is disposed in association with said reaction zone and while continuously withdrawing said reaction-formed non-fluorinated compound medium (B) phase containing said reaction product from said phase separation zone.

4. The method according to claim 3, wherein M in said formulae (1) and (2) represents tin, and said reaction which proceeds in the presence of a Lewis acid catalyst is selected from the group consisting of an oxidation reaction of a ketone compound by use of hydrogen peroxide and a transesterification reaction.

5. The method according to claim 3, wherein M in said formulae (1) and (2) represents hafnium, and said reaction which proceeds in the presence of a Lewis acid catalyst is selected from the group consisting of a carbon-carbon bond-forming reaction, a dehydration reaction and an oxidation reaction by use of hydrogen peroxide.

6. A Lewis acid catalyst which is a compound represented by the following formula (1'): [(R.sub.f.sup.1SO.sub.2)(R.sub.f.sup.2SO.sub.2)N].sub.nM (1') wherein: each of R.sub.f.sup.1 and R.sub.f.sup.2 independently represents a substituent selected from the group consisting of a perfluorinated, saturated C.sub.9 C.sub.16 hydrocarbon group containing in the skeleton thereof at least one heteroatom selected from the group consisting of a nitrogen atom and an oxygen atom and a partially substituted derivative thereof, wherein, in said partially substituted derivative in the definition of said substituent, a part of the fluorine atoms in said perfluorinated hydrocarbon group is replaced by at least one member selected from the group consisting of a hydrogen atom and a halogen atom exclusive of a fluorine atom, provided that, in said substituent, a part of the fluorine atoms bonded to said carbon atom directly bonded to the --SO.sub.2 group is not replaced by a hydrogen atom; M represents an atom selected from the group consisting of transition metals including rare earth metals, gallium, indium, thallium, silicon, germanium, tin, lead, antimony and bismuth; and n is an integer equivalent to the valence of M.

7. The Lewis acid catalyst according to claim 6, wherein each of R.sub.f.sup.1 and R.sub.f.sup.2 in said formula (1') represents a substituent represented by the following formula (3): CF.sub.2X.sup.1CFX.sup.2--[OCF.sub.2CF(CF.sub.3)].sub.t--O--[CF.sub.2].su- b.u-- (3) wherein, each of X.sup.1 and X.sup.2 independently represents an atom selected from the group consisting of a halogen atom and a hydrogen atom; t is an integer of from 1 to 4; and u is an integer of from 1 to 4.

8. The Lewis acid catalyst according to claim 6 or 7, wherein M in said formula (1') represents tin.

9. The Lewis acid catalyst according to claim 6 or 7, wherein M in said formula (1') represents hafnium.

10. A Lewis acid catalyst which is a compound represented by the following formula (2'): [(R.sub.f.sup.1SO.sub.2)(R.sub.f.sup.2SO.sub.2)(R.sub.f.sup.3SO.sub.2)C].- sub.nM (2') wherein: each of R.sub.f.sup.1 to R.sub.f.sup.3 in said formula (2') represents a substituent represented by the following formula (3): CF.sub.2X.sup.1CFX.sup.2--[OCF.sub.2CF(CF.sub.3)].sub.t--O--[CF.sub.2].su- b.u-- (3) wherein, each of X.sup.1 and X.sup.2 independently represents an atom selected from the group consisting of a halogen atom and a hydrogen atom; t is an integer of from 1 to 4; and u is an integer of from 1 to 4; M represents an atom selected from the group consisting of transition metals including rare earth metals, gallium, indium, thallium, silicon, germanium, tin, lead, antimony and bismuth; and n is an integer equivalent to the valence of M.

11. The Lewis acid catalyst according to claim 10, wherein M in said formula (2') represents tin.

12. The Lewis acid catalyst according to claim 10, wherein M in said formula (2') represents hafnium.

13. A Lewis acid catalyst which is at least one compound selected from the group consisting of compounds respectively represented by the following formulae (5) and (6): [(R.sub.f.sup.1SO.sub.2)(R.sub.f.sup.2SO.sub.2)N].sub.nSn (5), and [(R.sub.f.sup.1SO.sub.2)(R.sub.f.sup.2SO.sub.2)(R.sub.f.sup.3SO.sub.2)C].- sub.nSn (6) wherein: each of R.sub.f.sup.1 to R.sub.f.sup.3 independently represents a substituent (.alpha.) selected from the group consisting of a perfluorinated, saturated or unsaturated C.sub.7 C.sub.20 hydrocarbon group containing in the skeleton thereof at least one heteroatom selected from the group consisting of a nitrogen atom and an oxygen atom and a partially substituted derivative thereof, or a substituent (.beta.) selected from the group consisting of a perfluorinated, saturated or unsaturated C.sub.1 C.sub.16 hydrocarbon group containing no heteroatom and a partially substituted derivative thereof, provided that, in formula (5) above, at least one member selected from the group consisting of R.sub.f.sup.1 and R.sub.f.sup.2 is said substituent (.alpha.) and, in formula (6) above, at least one member selected from the group consisting of R.sub.f.sup.1 to R.sub.f.sup.3 is said substituent (.alpha.), wherein, in said partially substituted derivative in the definition of each of said substituents (.alpha.) and (.beta.), a part of the fluorine atoms in said perfluorinated hydrocarbon group is replaced by at least one member selected from the group consisting of a hydrogen atom and a halogen atom exclusive of a fluorine atom, provided that, in each of said substituents (.alpha.) and (.beta.), a part of the fluorine .quadrature.atoms bonded to a carbon atom directly bonded to the --SO.sub.2 group is not replaced by a hydrogen atom; and n is an integer equivalent to the valence of Sn.

14. A Lewis acid catalyst which is at least one compound selected from the group consisting of compounds respectively represented by the following formulae (7) and (8): [(R.sub.f.sup.1SO.sub.2)(R.sub.f.sup.2SO.sub.2)N].sub.nHf (7), and [(R.sub.f.sup.1SO.sub.2)(R.sub.f.sup.2SO.sub.2)(R.sub.f.sup.3SO.sub.2)C].- sub.nHf (8) wherein: each of R.sub.f.sup.1 to R.sub.f.sup.3 independently represents a substituent (.alpha.) selected from the group consisting of a perfluorinated, saturated or unsaturated C.sub.7 C.sub.20 hydrocarbon group containing in the skeleton thereof at least one heteroatom selected from the group consisting of a nitrogen atom and an oxygen atom and a partially substituted derivative thereof, or a substituent (.beta.) selected from the group consisting of a perfluorinated, saturated or unsaturated C.sub.1 C.sub.16 hydrocarbon group containing no heteroatom and a partially substituted derivative thereof, provided that, in formula (7) above, at least one member selected from the group consisting of R.sub.f.sup.1 and R.sub.f.sup.2 is said substituent (.alpha.) and, in formula (8) above, at least one member selected from the group consisting of R.sub.f.sup.1 to R.sub.f.sup.3 is said substituent (.alpha.), wherein, in said partially substituted derivative in the definition of each of said substituents (.alpha.) and (.beta.), a part of the fluorine atoms in said perfluorinated hydrocarbon group is replaced by at least one member selected from the group consisting of a hydrogen atom and a halogen atom exclusive of a fluorine atom, provided that, in each of said substituents (.alpha.) and (.beta.), a part of the fluorine atoms bonded to a carbon atom directly bonded to the --SO.sub.2 group is not replaced by a hydrogen atom; and n is an integer equivalent to the valence of Hf.

---

Description

---

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a Lewis acid catalyst composition. More particularly, the present invention is concerned with a Lewis acid catalyst composition comprising a specific mixed medium and a Lewis acid catalyst which is a compound comprising a specific ligand, wherein the ligand contains a substituent selected from the group consisting of a perfluorinated, saturated or unsaturated C.sub.7 C.sub.20 hydrocarbon group containing in the skeleton thereof at least one heteroatom selected from the group consisting of a nitrogen atom and an oxygen atom and a partially substituted derivative of the above-mentioned C.sub.7 C.sub.20 hydrocarbon group. The Lewis acid catalyst composition of the present invention exhibits high catalytic activity by virtue of its improved solubility. By the use of the Lewis acid catalyst composition of the present invention for a Lewis acid-catalyzed reaction, after the reaction, not only can the Lewis acid catalyst be easily separated and recovered from the catalytic reaction mixture containing the same, but also the recycling of the Lewis acid catalyst can be performed without suffering the lowering of the catalytic activity. The present invention is also concerned with a method for continuously performing a reaction which proceeds in the presence of the above-mentioned Lewis acid catalyst by using the above-mentioned specific mixed solvent and the Lewis acid catalyst. Further, the present invention is also concerned with a novel Lewis acid catalyst.

2. Prior Art

A Lewis acid catalyst has been employed in various acid-catalyzed reactions for the synthesis of organic compounds. However, known Lewis acid catalysts, such as aluminum chloride, boron trifluoride and titanium tetrachloride, has problems in that the catalytic reaction systems are only limited to those in which the reactions proceed stoichiometrically and those in which the types of reaction solvents used are limited.

As a Lewis acid compound, a metal salt of a sulfonylimide or sulfonylmethide comprising a fluorine-substituted compound essentially having a polymerization-active species is disclosed in Canadian Patent No. 2,236,196 and this Lewis acid compound is used as a raw material for a membrane of a fuel cell. Further, an alkali metal salt or alkaline earth metal salt of a sulfonylimide or sulfonylmethide comprising a perfluoroalkyl group is disclosed in International Patent Application Publication No. WO 99/45048. In addition, an alkali metal salt or alkaline earth metal salt of a fluorine-substituted compound comprising a carbon-carbon double bond is disclosed in U.S. Pat. No. 5,463,005. A metal salt of a sulfonylimide comprising a perfluoroalkyl group is disclosed in Japanese Patent Application prior-to-examination Publication (Tokuhyo) No. 2001-526451. However, none of the above-mentioned patent documents describe that the metal salts disclosed therein, which are Lewis acid compounds, can be used as excellent Lewis acid catalysts having high catalytic activity. Further, these patent documents have no description about a Lewis acid catalyst composition which uses the Lewis acid compound and a fluorinated compound medium in combination.

Recently, Unexamined Japanese Patent Application Publication Nos. Hei 7-246338 and Hei 10-230167 disclose that a metal salt of a bis(perfluoroalkanesulfonyl)imide is an excellent Lewis acid catalyst having high catalytic activity. Further, Unexamined Japanese Patent Application Publication No. 2000-219692 discloses that a tris(perfluoroalkanesulfonyl)methide is an excellent Lewis acid catalyst.

In general, organometal complex catalysts are used so as to catalyze reactions which proceed in a homogeneous reaction system and, therefore, the use of such catalysts in the catalytic reaction system has a problem in that, in the commercial practice of the catalytic reaction, after the reaction, the separation and recovery of the catalyst from the reaction mixture and the recycling of the recovered catalyst are accompanied with difficulties.

For solving such a problem, a number of proposals have been made with respect to methods for separating and recovering a Lewis acid catalyst employed in a reaction. As an example of the methods, there can be mentioned a method in which a Lewis acid catalyst is immobilized. For example, a study has been made about the method which comprises fixing a catalyst to an inorganic or macromolecular carrier to thereby obtain an immobilized catalyst, and effecting a solid phase synthetic reaction by dispersing the obtained immobilized catalyst in the reaction system.

Although the immobilized catalyst can be easily recovered from the synthetic reaction system, the solid phase synthetic reaction has problems in that not only is the catalytic activity lowered, but also the solid phase synthetic reaction is not applicable to all of the organic syntheses which are generally conducted in a homogeneous liquid phase. Therefore, it has been desired to develop a technique which is advantageous not only in that a reaction efficiency in a liquid phase is increased, and a post-treatment of the reaction mixture can be done simply, but also in that the catalyst used can be easily recovered and recycled. It has especially been desired to develop a method for separation, recovery and recycling of a Lewis acid catalyst, which can be widely used for various acid-catalyzed reactions.

In this situation, in Unexamined Japanese Patent Application Publication No. 2001-190962, the present inventors disclosed a Lewis acid catalyst composition for use in an acid-catalyzed reaction. In this patent document, a Lewis acid-catalyzed reaction is performed in a mixed medium comprising a perfluorinated hydrocarbon and a non-fluorinated hydrocarbon and, then, the Lewis acid catalyst is recovered and recycled by the phase separation of the resultant reaction mixture. Although this method enables the recovery and recycling of the used catalyst, this method has the following problems. When a Lewis acid catalyst reaction is performed using the Lewis acid catalyst composition of the above-mentioned patent document, due to the relatively low rate of phase separation of the reaction mixture, a lowering of the productivity is caused, so that complicated apparatuses become necessary for performing the reaction in a continuous manner, and costs for the apparatuses become high. Therefore, it has been desired to develop a Lewis acid catalyst composition and a Lewis acid catalyst which are advantageous from the viewpoint of improvement in not only the recovery of the used catalyst, but also the yield of the reaction product.

SUMMARY OF THE INVENTION

In this situation, with a view toward solving the above-mentioned problems, the present inventors have conducted extensive and intensive studies about the mutual behaviors of raw materials, a Lewis acid catalyst, a reaction medium and a reaction product in a reaction system containing these substances. As a result, it has unexpectedly been found that, when an acid-catalyzed reaction is performed using a specific Lewis acid catalyst composition which comprises a Lewis acid catalyst containing a specific substituent and a mixed medium comprising a specific fluorinated compound medium and a specific non-fluorinated compound medium, the Lewis acid catalyst exhibits high catalytic activity by virtue of its improved solubility in the fluorinated compound medium. Further, the resultant reaction mixture can separate rapidly into a catalyst phase having the catalyst dissolved therein and a product phase having a reaction product dissolved therein and, therefore, the Lewis acid catalyst can be easily recovered on one hand, and the catalyst recovery ratio can be improved on the other hand. The present inventors have also found that, by virtue of its very high phase separation rate, the above-mentioned Lewis acid catalyst composition can be advantageously used so as to perform a continuous reaction.

On the other hand, in the course of the above-mentioned study, the present inventors have also found a novel Lewis acid catalyst having high solubility in a fluorinated compound medium and having high catalytic activity as compared to those of the conventional Lewis acid catalysts.

Accordingly, it is an object of the present invention to provide a Lewis acid catalyst composition which, when used for effecting a reaction in the presence of a raw material or raw materials, enables a catalyst and a reaction product to be easily separated and recovered from the resultant reaction mixture, so that the recycling of the catalyst becomes possible.

It is another object of the present invention to provide a method for continuously performing a reaction which proceeds in the presence of a Lewis acid catalyst.

It is still another object of the present invention to provide a novel Lewis acid catalyst which has high stability in water and has high catalytic activity as compared to those of the conventional Lewis acid catalysts, and which can be widely used for various acid-catalyzed reactions.

The foregoing and other objects, features and advantages of the present invention will be apparent to those skilled in the art from the following detailed description and the appended claims.

DETAILED DESCRIPTION OF THE INVENTION

In one aspect of the present invention, there is provided a Lewis acid catalyst composition comprising a mixed medium and a Lewis acid catalyst,

the mixed medium comprising (A) a fluorinated compound medium and (B) a non-fluorinated compound medium,

the Lewis acid catalyst being at least one compound selected from the group consisting of compounds respectively represented by the following formulae (1) and (2): [(R.sub.f.sup.1SO.sub.2)(R.sub.f.sup.2SO.sub.2)N].sub.nM (1), and [(R.sub.f.sup.1SO.sub.2)(R.sub.f.sup.2SO.sub.2)(R.sub.f.sup.3SO.sub.2)C].- sub.nM (2) wherein: each of R.sub.f.sup.1 to R.sub.f.sup.3 independently represents a substituent (.alpha.) selected from the group consisting of a perfluorinated, saturated or unsaturated C.sub.7 C.sub.20 hydrocarbon group containing in the skeleton thereof at least one heteroatom selected from the group consisting of a nitrogen atom and an oxygen atom and a partially substituted derivative thereof, or a substituent (.beta.) selected from the group consisting of a perfluorinated, saturated or unsaturated C.sub.1 C.sub.16 hydrocarbon group containing no heteroatom and a partially substituted derivative thereof, provided that, in formula (1) above, at least one member selected from the group consisting of R.sub.f.sup.1 and R.sub.f.sup.2 is the substituent (.beta.) and, in formula (2) above, at least one member selected from the group consisting of R.sub.f.sup.1 to R.sub.f.sup.3 is the substituent (.alpha.), wherein, in the partially substituted derivative in the definition of each of the substituents (.alpha.) and (.beta.), a part of the fluorine atoms in the perfluorinated hydrocarbon group is replaced by at least one member selected from the group consisting of a hydrogen atom and a halogen atom exclusive of a fluorine atom, provided that, in each of the substituents (.alpha.) and (.beta.), a part of the fluorine atoms bonded to a carbon atom directly bonded to the --SO.sub.2 group is not replaced by a hydrogen atom; M represents an atom selected from the group consisting of transition metals including rare earth metals, gallium, indium, thallium, silicon, germanium, tin, lead, antimony and bismuth; and n is an integer equivalent to the valence of M.

For an easy understanding of the present invention, the essential features and various preferred embodiments of the present invention are enumerated below. 1. A Lewis acid catalyst composition comprising a mixed medium and a Lewis acid catalyst,

the mixed medium comprising (A) a fluorinated compound medium and (B) a non-fluorinated compound medium,

the Lewis acid catalyst being at least one compound selected from the group consisting of compounds respectively represented by the following formulae (1) and (2): [(R.sub.f.sup.1SO.sub.2)(R.sub.f.sup.2SO.sub.2)N].sub.nM (1), and [(R.sub.f.sup.1SO.sub.2)(R.sub.f.sup.2SO.sub.2)(R.sub.f.sup.3SO.sub.2)C].- sub.nM (2) wherein: each of R.sub.f.sup.1 to R.sub.f.sup.3 independently represents a substituent (.alpha.) selected from the group consisting of a perfluorinated, saturated or unsaturated C.sub.7 C.sub.20 hydrocarbon group containing in the skeleton thereof at least one heteroatom selected from the group consisting of a nitrogen atom and an oxygen atom and a partially substituted derivative thereof, or a substituent (.beta.) selected from the group consisting of a perfluorinated, saturated or unsaturated C.sub.1 C.sub.16 hydrocarbon group containing no heteroatom and a partially substituted derivative thereof, provided that, in formula (1) above, at least one member selected from the group consisting of R.sub.f.sup.1 and R.sub.f.sup.2 is the substituent (.alpha.) and, in formula (2) above, at least one member selected from the group consisting of R.sub.f.sup.1 to R.sub.f.sup.3 is the substituent (.alpha.), wherein, in the partially substituted derivative in the definition of each of the substituents (.alpha.) and (.beta.), a part of the fluorine atoms in the perfluorinated hydrocarbon group is replaced by at least one member selected from the group consisting of a hydrogen atom and a halogen atom exclusive of a fluorine atom, provided that, in each of the substituents (.alpha.) and (.beta.), a part of the fluorine atoms bonded to a carbon atom directly bonded to the --SO.sub.2 group is not replaced by a hydrogen atom; M represents an atom selected from the group consisting of transition metals including rare earth metals, gallium, indium, thallium, silicon, germanium, tin, lead, antimony and bismuth; and n is an integer equivalent to the valence of M. 2. The Lewis acid catalyst composition according to item 1 above, wherein each of R.sub.f.sup.1 to R.sub.f.sup.3 in the formulae (1) and (2) independently represents substituent (.alpha.) which is represented by any one of the following formulae (3) and (4): CF.sub.2X.sup.1CFX.sup.2--[OCF.sub.2CF(CF.sub.3)].sub.t--O--[CF.sub.2].su- b.u-- (3), and CF.sub.2.dbd.CF--[OCF.sub.2CF(CF.sub.3)].sub.t--O--[CF.sub.2].sub.u-- (4) wherein, each of X.sup.1 and X.sup.2 independently represents an atom selected from the group consisting of a halogen atom and a hydrogen atom; t is an integer of from 1 to 4; and u is an integer of from 1 to 4. 3. A method for continuously performing a reaction which proceeds in the presence of a Lewis acid catalyst, which comprises: providing a reaction zone containing a Lewis acid catalyst and a fluorinated compound medium (A), wherein the Lewis acid catalyst is at least one compound selected from the group consisting of compounds respectively represented by the following formulae (1) and (2): [(R.sub.f.sup.1SO.sub.2)(R.sub.f.sup.2SO.sub.2)N].sub.nM (1), and [(R.sub.f.sup.1SO.sub.2)(R.sub.f.sup.2SO.sub.2)(R.sub.f.sup.3SO.sub.2)C].- sub.nM (2) wherein: each of R.sub.f.sup.1 to R.sub.f.sup.3 independently represents a substituent (.alpha.) selected from the group consisting of a perfluorinated, saturated or unsaturated C.sub.7 C.sub.20 hydrocarbon group containing in the skeleton thereof at least one heteroatom selected from the group consisting of a nitrogen atom and an oxygen atom and a partially substituted derivative thereof, or a substituent (.beta.) selected from the group consisting of a perfluorinated, saturated or unsaturated C.sub.1 C.sub.16 hydrocarbon group containing no heteroatom and a partially substituted derivative thereof, provided that, in formula (1) above, at least one member selected from the group consisting of R.sub.f.sup.1 and R.sub.f.sup.2 is the substituent (.alpha.) and, in formula (2) above, at least one member selected from the group consisting of R.sub.f.sup.1 to R.sub.f.sup.3 is the substituent (.alpha.), wherein, in the partially substituted derivative in the definition of each of the substituents (.alpha.) and (.beta.), a part of the fluorine atoms in the perfluorinated hydrocarbon group is replaced by at least one member selected from the group consisting of a hydrogen atom and a halogen atom exclusive of a fluorine atom, provided that, in each of the substituents (.alpha.) and (.beta.), a part of the fluorine atoms bonded to a carbon atom directly bonded to the --SO.sub.2 group is not replaced by a hydrogen atom, M represents an atom selected from the group consisting of transition metals including rare earth metals, gallium, indium, thallium, silicon, germanium, tin, lead, antimony and bismuth, and n is an integer equivalent to the valence of M; and continuously feeding a mixture of at least one reactant and a non-fluorinated compound medium (B) and mixing the fluorinated compound medium (A) containing the Lewis acid catalyst and the non-fluorinated compound medium (B) containing at least one reactant to thereby effect a reaction in the presence of the Lewis acid catalyst and obtain a reaction mixture comprising a reaction-formed fluorinated compound medium (A) phase containing the Lewis acid catalyst and a reaction-formed non-fluorinated compound medium (B) phase containing a reaction product, while continuously separating the reaction-formed non-fluorinated compound medium (B) phase containing the reaction product from the reaction-formed fluorinated compound medium (A) phase containing the Lewis acid catalyst in a phase separation zone which is disposed in association with the reaction zone and while continuously withdrawing the reaction-formed non-fluorinated compound medium (B) phase containing the reaction product from the phase separation zone. 4. A Lewis acid catalyst which is a compound represented by the following formula (1'): [(R.sub.f.sup.1SO.sub.2)(R.sub.f.sup.2SO.sub.2)N].sub.nM (1') wherein: each of R.sub.f.sup.1 and R.sub.f.sup.2 independently represents a substituent selected from the group consisting of a perfluorinated, saturated C.sub.9 C.sub.16 hydrocarbon group containing in the skeleton thereof at least one heteroatom selected from the group consisting of a nitrogen atom and an oxygen atom and a partially substituted derivative thereof, wherein, in the partially substituted derivative in the definition of the substituent, a part of the fluorine atoms in the perfluorinated hydrocarbon group is replaced by at least one member selected from the group consisting of a hydrogen atom and a halogen atom exclusive of a fluorine atom, provided that, in the substituent, a part of the fluorine atoms bonded to the carbon atom directly bonded to the --SO.sub.2 group is not replaced by a hydrogen atom; M represents an atom selected from the group consisting of transition metals including rare earth metals, gallium, indium, thallium, silicon, germanium, tin, lead, antimony and bismuth; and n is an integer equivalent to the valence of M. 5. The Lewis acid catalyst according to item 4 above, wherein each of R.sub.f.sup.1 and R.sub.f.sup.2 in the formula (1') represents a substituent represented by the following formula (3): CF.sub.2X.sup.1CFX.sup.2--[OCF.sub.2CF(CF.sub.3)].sub.t--O--[CF.sub.2].su- b.u-- (3) wherein, each of X.sup.1 and X.sup.2 independently represents an atom selected from the group consisting of a halogen atom and a hydrogen atom; t is an integer of from 1 to 4; and u is an integer of from 1 to 4. 6. The Lewis acid catalyst according to item 4 or 5 above, wherein M in the formula (1') represents tin, and the Lewis acid catalyst is for use in catalyzing an oxidation reaction of a ketone compound by use of hydrogen peroxide. 7. The Lewis acid catalyst according to item 4 or 5 above, wherein M in the formula (1') represents tin, and the Lewis acid catalyst is for use in catalyzing a transesterification reaction. 8. The Lewis acid catalyst according to item 4 or 5 above, wherein M in the formula (1') represents hafnium, and the Lewis acid catalyst is for use in catalyzing a reaction selected from the group consisting of a carbon-carbon bond-forming reaction, a dehydration reaction and an oxidation reaction by use of hydrogen peroxide. 9. A Lewis acid catalyst which is a compound represented by the following formula (2'): [(R.sub.f.sup.1SO.sub.2)(R.sub.f.sup.2SO.sub.2)(R.sub.f.sup.3SO.sub.2)C].- sub.nM (2') wherein: each of R.sub.f.sup.1 to R.sub.f.sup.3 in the formula (2') represents a substituent represented by the following formula (3): CF.sub.2X.sup.1CFX.sup.2--[OCF.sub.2CF(CF.sub.3)].sub.t--O--[CF.sub.2].su- b.u-- (3) wherein, each of X.sup.1 and X.sup.2 independently represents an atom selected from the group consisting of a halogen atom and a hydrogen atom; t is an integer of from 1 to 4; and u is an integer of from 1 to 4; M represents an atom selected from the group consisting of transition metals including rare earth metals, gallium, indium, thallium, silicon, germanium, tin, lead, antimony and bismuth; and n is an integer equivalent to the valence of M. 10. The Lewis acid catalyst according to item 9 above, wherein M in the formula (2') represents tin, and the Lewis acid catalyst is for use in catalyzing an oxidation reaction of a ketone compound by use of hydrogen peroxide. 11. The Lewis acid catalyst according to item 9 above, wherein M in the formula (2') represents tin, and the Lewis acid catalyst is for use in catalyzing a transesterification reaction. 12. The Lewis acid catalyst according to item 9 above, wherein M in the formula (2') represents hafnium, and the Lewis acid catalyst is for use in catalyzing a reaction selected from the group consisting of a carbon-carbon bond-forming reaction, a dehydration reaction and an oxidation reaction by use of hydrogen peroxide. 13. A Lewis acid catalyst which is at least one compound selected from the group consisting of compounds respectively represented by the following formulae (5) and (6): [(R.sub.f.sup.1SO.sub.2)(R.sub.f.sup.2SO.sub.2)N].sub.nSn (5), and [(R.sub.f.sup.1SO.sub.2)(R.sub.f.sup.2SO.sub.2)(R.sub.f.sup.3SO.sub.2)C].- sub.nSn (6) wherein: each of R.sub.f.sup.1 to R.sub.f.sup.3 independently represents a substituent (.alpha.) selected from the group consisting of a perfluorinated, saturated or unsaturated C.sub.7 C.sub.20 hydrocarbon group containing in the skeleton thereof at least one heteroatom selected from the group consisting of a nitrogen atom and an oxygen atom and a partially substituted derivative thereof, or a substituent (.beta.) selected from the group consisting of a perfluorinated, saturated or unsaturated C.sub.1 C.sub.16 hydrocarbon group containing no heteroatom and a partially substituted derivative thereof, provided that, in formula (5) above, at least one member selected from the group consisting of R.sub.f.sup.1 and R.sub.f.sup.2 is the substituent (.alpha.) and, in formula (6) above, at least one member selected from the group consisting of R.sub.f.sup.1 to R.sub.f.sup.3 is the substituent (.alpha.), wherein, in the partially substituted derivative in the definition of each of the substituents (.alpha.) and (.beta.), a part of the fluorine atoms in the perfluorinated hydrocarbon group is replaced by at least one member selected from the group consisting of a hydrogen atom and a halogen atom exclusive of a fluorine atom, provided that, in each of the substituents (.alpha.) and (.beta.), a part of the fluorine atoms bonded to a carbon atom directly bonded to the --SO.sub.2 group is not replaced by a hydrogen atom; and n is an integer equivalent to the valence of Sn, the Lewis acid catalyst being for use in catalyzing a reaction selected from the group consisting of an oxidation reaction of a ketone compound by use of hydrogen peroxide and a transesterification reaction. 14. A Lewis acid catalyst which is at least one compound selected from the group consisting of compounds respectively represented by the following formulae (7) and (8): [(R.sub.f.sup.1SO.sub.2)(R.sub.f.sup.2SO.sub.2)N].sub.nHf (7), and [(R.sub.f.sup.1SO.sub.2)(R.sub.f.sup.2SO.sub.2)(R.sub.f.sup.3SO.sub.2)C].- sub.nHf (8) wherein: each of R.sub.f.sup.1 to R.sub.f.sup.3 independently represents a substituent (.alpha.) selected from the group consisting of a perfluorinated, saturated or unsaturated C.sub.7 C.sub.20 hydrocarbon group containing in the skeleton thereof at least one heteroatom selected from the group consisting of a nitrogen atom and an oxygen atom and a partially substituted derivative thereof, or a substituent (.beta.) selected from the group consisting of a perfluorinated, saturated or unsaturated C.sub.1 C.sub.16 hydrocarbon group containing no heteroatom and a partially substituted derivative thereof, provided that, in formula (7) above, at least one member selected from the group consisting of R.sub.f.sup.1 and R.sub.f.sup.2 is the substituent (.alpha.) and, in formula (8) above, at least one member selected from the group consisting of R.sub.f.sup.1 to R.sub.f.sup.3 is the substituent (.alpha.), wherein, in the partially substituted derivative in the definition of each of the substituents (.alpha.) and (.beta.), a part of the fluorine atoms in the perfluorinated hydrocarbon group is replaced by at least one member selected from the group consisting of a hydrogen atom and a halogen atom exclusive of a fluorine atom, provided that, in each of the substituents (.alpha.) and (.beta.), a part of the fluorine atoms bonded to a carbon atom directly bonded to the --SO.sub.2 group is not replaced by a hydrogen atom; and n is an integer equivalent to the valence of Hf, the Lewis acid catalyst being for use in catalyzing a reaction selected from the group consisting of a carbon-carbon bond-forming reaction, a dehydration reaction and an oxidation reaction by use of hydrogen peroxide.

Hereinbelow, the present invention will be described in more detail.

The Lewis acid catalyst composition of the present invention comprises a mixed medium and a Lewis acid catalyst. The Lewis acid catalyst contained in the Lewis acid catalyst composition of the present invention is at least one compound selected from the group consisting of compounds respectively represented by the following formulae (1) and (2): [(R.sub.f.sup.1SO.sub.2)(R.sub.f.sup.2SO.sub.2)N].sub.nM (1), and [(R.sub.f.sup.1SO.sub.2)(R.sub.f.sup.2SO.sub.2)(R.sub.f.sup.3SO.sub.2)C].- sub.nM (2) wherein: each of R.sub.f.sup.1 to R.sub.f.sup.3 independently represents a substituent (.alpha.) selected from the group consisting of a perfluorinated, saturated or unsaturated C.sub.7 C.sub.20 hydrocarbon group containing in the skeleton thereof at least one heteroatom selected from the group consisting of a nitrogen atom and an oxygen atom and a partially substituted derivative of the C.sub.7 C.sub.20 hydrocarbon group above, or a substituent (.beta.) selected from the group consisting of a perfluorinated, saturated or unsaturated C.sub.1 C.sub.16 hydrocarbon group containing no heteroatom and a partially substituted derivative of the C.sub.7 C.sub.20 hydrocarbon group above, provided that, in formula (1) above, at least one member selected from the group consisting of R.sub.f.sup.1 and R.sub.f.sup.2 is the substituent (.alpha.) and, in formula (2) above, at least one member selected from the group consisting of R.sub.f.sup.1 to R.sub.f.sup.3 is the substituent (.alpha.), wherein, in the partially substituted derivative in the definition of each of the substituents (.alpha.) and (.beta.), a part of the fluorine atoms in the perfluorinated hydrocarbon group is replaced by at least one member selected from the group consisting of a hydrogen atom and a halogen atom exclusive of a fluorine atom, provided that, in each of the substituents (.alpha.) and (.beta.), a part of the fluorine atoms bonded to a carbon atom directly bonded to the --SO.sub.2 group is not replaced by a hydrogen atom; M represents an atom selected from the group consisting of transition metals including rare earth metals, gallium, indium, thallium, silicon, germanium, tin, lead, antimony and bismuth; and n is an integer equivalent to the valence of M.

Each of the compounds respectively represented by formulae (1) and (2) above, which are the Lewis acid catalysts contained in the Lewis acid catalyst composition of the present invention, contains at least one substituent (.alpha.). The substituent (.alpha.) is a substituent selected from the group consisting of a perfluorinated, saturated or unsaturated C.sub.7 C.sub.20 hydrocarbon group containing in the skeleton thereof at least one heteroatom selected from the group consisting of a nitrogen atom and an oxygen atom and a partially substituted derivative of the C.sub.7 C.sub.20 hydrocarbon group above. The number of carbon atoms of substituent (.alpha.) is 7 to 20, wherein lower limit of the number of carbon atoms is preferably 8, more preferably 9, most preferably 10, and upper limit of the number of carbon atoms is preferably 18, more preferably 16, most preferably 13. When substituent (.alpha.) has 7 to 20 carbon atoms, a Lewis acid catalyst comprising such a substituent (.alpha.) is well soluble in a fluorinated compound medium (A) and is fixed therein without dissolving into a non-fluorinated compound medium (B). Therefore, after performing a reaction in the presence of such a Lewis acid catalyst, the Lewis acid catalyst used can be easily separated from the reaction system.

In addition to the substituent (.alpha.), each of the compounds respectively represented by formulae (1) and (2) above may have a substituent (.beta.).

In addition to the substituent (.alpha.) containing a heteroatom, the compounds respectively represented by formulae (1) and (2) above may additionally have a substituent (.beta.) selected from the group consisting of a perfluorinated, saturated or unsaturated C.sub.1 C.sub.16 hydrocarbon group containing no heteroatom and a partially substituted derivative of the C.sub.1 C.sub.16 hydrocarbon group above. The number of carbon atoms of substituent (.beta.) is 1 to 16, wherein lower limit of the number of carbon atoms is preferably 2, more preferably 3, most preferably 4, and upper limit of the number of carbon atoms is preferably 14, more preferably 12, most preferably 10.

When the Lewis acid catalyst used in the Lewis acid catalyst composition of the present invention is a compound represented by formula (1) above, at least one member selected from the group consisting of R.sub.f.sup.1 and R.sub.f.sup.2 is the substituent (.alpha.). When the Lewis acid catalyst is a compound represented by formula (2) above, at least one member selected from the group consisting of R.sub.f.sup.1 to R.sub.f.sup.3 is the substituent (.alpha.). That is, a compound used as a Lewis acid catalyst in the Lewis acid catalyst composition of the present invention necessarily has at least one substituent (.alpha.) containing a heteroatom. Accordingly, a compound having only substituent (.beta.) is not used as a Lewis acid catalyst in the present invention.

Further, when the Lewis acid catalyst is a compound represented by formula (1) above, it is preferred that the substituents R.sub.f.sup.1 and R.sub.f.sup.2 are not simultaneously an unsaturated perfluorinated hydrocarbon group or a partially substituted derivative thereof. When the Lewis acid catalyst is a compound represented by formula (2) above, it is preferred that the substituents R.sub.f.sup.1 to R.sub.f.sup.3 are not simultaneously an unsaturated perfluorinated hydrocarbon group or a partially substituted derivative thereof.

The "partially substituted derivative thereof" in the definition of each of the substituents (.alpha.) and (.beta.) is a substituent in which a part of the fluorine atoms in the perfluorinated hydrocarbon group is replaced by at least one member selected from the group consisting of a hydrogen atom and a halogen atom exclusive of a fluorine atom, provided that, in each of the substituents (.alpha.) and (.beta.), a part of the fluorine atoms bonded to a carbon atom directly bonded to the --SO.sub.2 group is not replaced by a hydrogen atom. A halogen atom exclusive of a fluorine atom is a chlorine atom, a bromine atom or an iodine atom, preferably a chlorine atom or a bromine atom, more preferably a chlorine atom.

The amount of the fluorine atoms substituted with a hydrogen atom or a halogen atom exclusive of a fluorine atom is preferably 40% or less, more preferably 30% or less, still more preferably 20% or less, most preferably 10% or less, based on the number of fluorine atoms contained in the corresponding perfluorinated saturated hydrocarbon group.

On the other hand, when the substituents (.alpha.) and (.beta.) are perfluorinated unsaturated hydrocarbon groups, preferred are those which have the carbon-carbon double bond in an amount of 40% or less, more preferably 30% or less, still more preferably 20% or less, most preferably 10% or less, based on the number of fluorine atoms contained in the corresponding perfluorinated saturated hydrocarbon group.

With respect to the compounds used as a Lewis acid catalyst in the Lewis acid catalyst composition of the present invention, it is preferred that each of R.sub.f.sup.1 to R.sub.f.sup.3 in the formulae (1) and (2) independently represents substituent (.alpha.) which is represented by any one of the following formulae (3) and (4): CF.sub.2X.sup.1CFX.sup.2--[OCF.sub.2CF(CF.sub.3)].sub.t--O--[CF.sub.2].su- b.u-- (3), and CF.sub.2.dbd.CF--[OCF.sub.2CF(CF.sub.3)].sub.t--O--[CF.sub.2].sub.u-- (4) wherein, each of X.sup.1 and X.sup.2 independently represents an atom selected from the group consisting of a halogen atom and a hydrogen atom; t is an integer of from 1 to 4; and u is an integer of from 1 to 4, preferably from 2 to 4, more preferably from 2 to 3.

The compounds having a specific structure represented by the formula (3) or (4) above are well soluble in a fluorinated compound medium (A) and, therefore, exhibit high catalytic activity, as compared to known Lewis acid catalysts (for example, aluminum chloride, titanium tetrachloride and boron trifluoride).

With respect to the compounds respectively represented by formula (1) and (2) above, it is preferred that each of R.sub.f.sup.1 to R.sub.f.sup.3 has 7 to 16 carbon atoms, more preferably 9 to 16 carbon atoms.

Specific examples of the substituent (.alpha.) containing at least one heteroatom include: --CF.sub.2CHFCF.sub.2OC.sub.4F.sub.9, --C.sub.4F.sub.8N(C.sub.4F.sub.9).sub.2, --CF.sub.2CF.sub.2OCF(CF.sub.3)CF.sub.2OCF.dbd.CF.sub.2, --CF.sub.2CF.sub.2OCF(CF.sub.3)CF.sub.2OCF(CF3)CF.sub.2OCF.dbd.CF.sub.2, --CF.sub.2CF.sub.2OCF(CF.sub.3)CF.sub.2OCHFCF.sub.3, --CF.sub.2CF.sub.2OCF(CF.sub.3)CF.sub.2OCF(CF.sub.3)CF.sub.2OCHFCF.sub.3, --CF.sub.2CF.sub.2O--CF(CF.sub.3)--CF.sub.2--OCF(CF.sub.3)--CF.sub.2OCF.s- ub.2CF.sub.3, --CF.sub.2CF.sub.2OCF(CF.sub.3)CF.sub.2OCFClCF.sub.3 and --CF.sub.2CF.sub.2OCF(CF.sub.3)CF.sub.2OCFClCF.sub.2Cl.

Specific examples of the substituent (.beta.) include a trifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluorobutyl group, a perfluoropentyl group, a perfluorohexyl group, a perfluoroheptyl group, a perfluorooctyl group, a perfluorononyl group, a perfluorodecyl group, a perfluoroundecyl group, a perfluorododecyl group, a perfluorotridecyl group, a perfluorotetradecyl group, a perfluoropentadecyl group and a perfluorohexadecyl group.

When the Lewis acid catalyst contained in the Lewis acid catalyst composition of the present invention is a compound represented by formula (1) above, the total number of carbon atoms of R.sub.f.sup.1 and R.sub.f.sup.2 is preferably 14 to 32, wherein lower limit of the number of carbon atoms is more preferably 16, still more preferably 18, most preferably 20, and upper limit of the number of carbon atoms is more preferably 26, most preferably 23.

When the Lewis acid catalyst contained in the Lewis acid catalyst composition of the present invention is a compound represented by formula (2) above, the total number of carbon atoms of R.sub.f.sup.1, R.sub.f.sup.2 and R.sub.f.sup.3 is preferably 21 to 48, wherein lower limit of the number of carbon atoms is more preferably 23, still more preferably 25, most preferably 27, and upper limit of the number of carbon atoms is more preferably 38, most preferably 34.

In the formulae (1) and (2) above, M represents an atom selected from the group consisting of transition metals including rare earth metals, gallium, indium, thallium, silicon, germanium, tin, lead, antimony and bismuth. With respect to the compound used as a Lewis acid catalyst in the present invention, rare earth metals, hafnium, bismuth, tin and gallium are preferred, and scandium, ytterbium, lanthanum, yttrium, hafnium, bismuth, tin and gallium are more preferred.

The below-mentioned Lewis acid catalysts of the present invention may be advantageously used as a Lewis acid catalyst in the Lewis acid catalyst composition of the present invention.

The mixed medium contained in the Lewis acid catalyst composition of the present invention comprises a fluorinated compound medium (A) and a non-fluorinated compound medium (B). The examples of such fluorinated compound medium (A) used in the present invention include a perfluorinated, saturated or unsaturated hydrocarbon and a perfluorinated, saturated or unsaturated hydrocarbon containing in the skeleton thereof at least one heteroatom selected from the group consisting of a nitrogen atom and an oxygen atom. When the perfluorinated hydrocarbon contains in the skeleton thereof a carbon-carbon double bond, an oxygen atom and/or a nitrogen atom, the total number of the carbon-carbon double bond, the oxygen atom and the nitrogen atom is preferably 40% or less, more preferably 30% or less, still more preferably 20% or less, most preferably 10% or less, based on the number of fluorine atoms contained in a corresponding perfluorinated saturated hydrocarbon.

With respect to the perfluorinated compound used as the fluorinated compound medium (A), there is no particular limitation as long as the perfluorinated compound is in a liquid form at room temperature. The perfluorinated compound medium (A) has preferably 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, most preferably 6 to 15 carbon atoms.

Specific examples of perfluorinated saturated compounds used as the fluorinated compound medium (A) include perfluorohexane, perfluoroheptane, perfluorooctane, perfluorononane, perfluorodecane, perfluoroundecane, perfluorododecane, perfluorocyclohexane, perfluoromethylcyclohexane, perfluorodecalin and perfluoromethyldecalin.

Specific examples of perfluorinated compounds having in the skeleton thereof at least one member selected from the group consisting of an oxygen atom, a nitrogen atom and a carbon-carbon double bond include perfluoro-2-butyltetrahydrofuran, perfluorotributylamine, perfluorotriethylamine, perfluoro-5-methyl-3,6-dioxanonane, 2H-perfluoro-5-methyl-3,6-dioxanonane, perfluoro-2,3,5-trimethylhexene and a low molecular weight polymer of hexafluoropropylene oxide.

As the fluorinated compound medium (A), these media can be used individually or in combination.

With respect to the non-fluorinated compound medium (B), there is no particular limitation as long as the non-fluorinated compound medium (B) is in a liquid form at room temperature and it can be phase-separated from the fluorinated compound medium (A). Examples of the non-fluorinated compound medium (B) include an alicyclic hydrocarbon and an aliphatic hydrocarbon; a halogenated aliphatic hydrocarbon exclusive of a fluorinated aliphatic hydrocarbon; an aromatic hydrocarbon; a halogenated aromatic hydrocarbon exclusive of a fluorinated aromatic hydrocarbon; an ester compound and an ether compound.

With respect to the aliphatic hydrocarbon used as a non-fluorinated compound medium (B), those which have 5 to 20 carbon atoms, preferably 5 to 16 carbon atoms, can be used. Preferred are linear or branched hydrocarbons having 8 to 16 carbon atoms. Alicyclic hydrocarbons having 5 to 16 carbon atoms are also preferred. Specific examples of such aliphatic or alicyclic hydrocarbons include n-heptane, n-octane, n-nonane, n-decane, n-dodecane, n-hexadecane, cyclopentane, cyclohexane and methylcyclohexane.

With respect to the halogenated aliphatic hydrocarbon exclusive of a fluorinated aliphatic hydrocarbon, there is no particular limitation with respect to the number of carbon atoms and the number of hydrogen atoms replaced by halogen atoms as long as the halogenated aliphatic hydrocarbon is in a liquid form at room temperature. However, C.sub.1 C.sub.10 halogenated aliphatic hydrocarbons are preferred. Specific examples of such halogenated aliphatic hydrocarbons include dichloromethane, dichloroethane and dibromoethane.

With respect to the aromatic hydrocarbon used as a non-fluorinated compound medium (B), those which have 6 to 15 carbon atoms are preferred. Specific examples of such aromatic hydrocarbons include benzene and benzene substituted with an alkyl group or groups, such as toluene, o-xylene, m-xylene, p-xylene and ethylbenzene.

With respect to the halogenated aromatic hydrocarbon exclusive of a fluorinated aromatic hydrocarbon, there is no particular limitation with respect to the number of hydrogen atoms replaced by halogen atoms. However, C.sub.6 C.sub.10 halogenated aromatic hydrocarbons are preferred. Specific examples of such halogenated aromatic hydrocarbons include chlorobenzene, dichlorobenzene, bromobenzene and chlorotoluene.

With respect to the ester compound used as a non-fluorinated compound medium (B), those which have 5 to 20 carbon atoms exclusive of the carbon atoms of the carbonyl group thereof, can be used. Preferred are ester compounds corresponding to a saturated hydrocarbon having 5 to 16 carbon atoms. More preferred are ester compounds corresponding to a linear, branched or cyclic saturated hydrocarbon or an aromatic hydrocarbon having 6 or more carbon atoms, more preferably 7 to 16 carbon atoms. Specific examples of such ester compounds include n-butyl acetate, iso-butyl acetate, tert-butyl acetate, n-pentyl acetate, iso-pentyl acetate, n-hexyl acetate, n-heptyl acetate, n-octyl acetate, n-nonyl acetate, n-decyl acetate, n-dodecyl acetate, cyclohexyl acetate, benzyl acetate, n-butyl propionate, iso-butyl propionate, tert-butyl propionate, n-pentyl propionate, iso-pentyl propionate, n-hexyl propionate, n-heptyl propionate, n-octyl propionate, n-nonyl propionate, n-decyl propionate, n-dodecyl propionate, cyclohexyl propionate, benzyl propionate, n-propyl butyrate, n-butyl butyrate, iso-butyl butyrate, tert-butyl butyrate, n-pentyl butyrate, iso-pentyl butyrate, n-hexyl butyrate, n-heptyl butyrate, n-octyl butyrate, n-nonyl butyrate, n-decyl butyrate, n-dodecyl butyrate, cyclohexyl butyrate, methyl benzoate, ethyl benzoate and propyl benzoate.

With respect to the ether compound used as a non -fluorinated compound medium (B), ether compounds corresponding to linear or branched saturated hydrocarbons having 3 to 15 carbon atoms can be used. Preferred are ether compounds corresponding to hydrocarbons having 4 or more carbon atoms, more preferably 6 to 15 carbon atoms. In addition, use can be made of cyclic ether compounds having 4 or more c