Provided are a fluorine-containing ether compound that can form a surface layer that excels in durability and a method of manufacturing the same, a fluorine-containing ether composition and a coating liquid, and an article having a surface layer that excels in durability and a method of manufacturing the same. A fluorine-containing ether compound is expressed by the following formula (A1) or (A2):

{R.sup.fO—(R.sup.f1O).sub.m1—(R.sup.1).sub.m2—(CHF).sub.m3—O—(CHF).sub.m4}.sub.n1-Q.sup.1(-T.sup.1).sub.n2   Formula (A1)

(T.sup.2).sub.n3-Q.sup.2-(CHF).sub.m5—O—(CHF).sub.m6—(R.sup.2).sub.m7—O—(R.sup.f2O).sub.m8—(R.sup.3).sub.m9—(CHF).sub.m10—O—(CHF).sub.m11-Q.sup.3(-T.sup.3).sub.n4  Formula (A2), in the above, the symbols in the formulas are as described in the specification.

Provided are a fluorine-containing ether compound that can form a surface layer that excels in durability and a method of manufacturing the same, a fluorine-containing ether composition and a coating liquid, and an article having a surface layer that excels in durability and a method of manufacturing the same. A fluorine-containing ether compound is expressed by the following formula (A1) or (A2):

{R.sup.fO—(R.sup.f1O).sub.m1—(R.sup.1).sub.m2—(CHF).sub.m3—O—(CHF).sub.m4}.sub.n1-Q.sup.1(-T.sup.1).sub.n2   Formula (A1)

(T.sup.2).sub.n3-Q.sup.2-(CHF).sub.m5—O—(CHF).sub.m6—(R.sup.2).sub.m7—O—(R.sup.f2O).sub.m8—(R.sup.3).sub.m9—(CHF).sub.m10—O—(CHF).sub.m11-Q.sup.3(-T.sup.3).sub.n4  Formula (A2), in the above, the symbols in the formulas are as described in the specification.

An object of the present invention is to provide a method for producing a fluorinated organic compound, whereby an iodosylbenzene derivative can be easily separated and recovered. The above object can be achieved by a method for producing a fluorinated organic compound, comprising step A of fluorinating an organic compound (1) by reaction with a fluorine source (3) in the presence of a hypervalent iodine aromatic ring compound (2a), or in the presence of an iodine aromatic ring compound (2b) and an oxidant (2bo); wherein the fluorine source (3) is a fluorine source (3a) represented by formula: MF.sub.n, wherein M is H, a metal of Group 1 of the periodic table, or a metal of Group 2 of the periodic table; and n is 1 or 2; and step B of separating the iodine aromatic ring compound from a reaction liquid after step A is started.

An object of the present invention is to provide a method for producing a fluorinated organic compound, whereby an iodosylbenzene derivative can be easily separated and recovered. The above object can be achieved by a method for producing a fluorinated organic compound, comprising step A of fluorinating an organic compound (1) by reaction with a fluorine source (3) in the presence of a hypervalent iodine aromatic ring compound (2a), or in the presence of an iodine aromatic ring compound (2b) and an oxidant (2bo); wherein the fluorine source (3) is a fluorine source (3a) represented by formula: MF.sub.n, wherein M is H, a metal of Group 1 of the periodic table, or a metal of Group 2 of the periodic table; and n is 1 or 2; and step B of separating the iodine aromatic ring compound from a reaction liquid after step A is started.

A production method of α,α-difluoroacetaldehyde according to the present invention includes reaction of an α,α-difluoroacetic acid ester with hydrogen gas (H.sub.2) in the presence of a ruthenium catalyst. It is possible to selectively obtain α,α-difluoroacetaldehyde as a partially reduced product of the hydrogenation reaction by the adoption of specific reaction conditions (in particular, reaction solvent and reaction temperature). This hydrogenation process can be alternative to the industrially unpractical hydride reduction process.

A production method of α,α-difluoroacetaldehyde according to the present invention includes reaction of an α,α-difluoroacetic acid ester with hydrogen gas (H.sub.2) in the presence of a ruthenium catalyst. It is possible to selectively obtain α,α-difluoroacetaldehyde as a partially reduced product of the hydrogenation reaction by the adoption of specific reaction conditions (in particular, reaction solvent and reaction temperature). This hydrogenation process can be alternative to the industrially unpractical hydride reduction process.

The present invention has the effect of making it possible to produce 1,1,1-trifluoro-2,2-bisarylethane efficiently by a simple procedure by condensing a mixture of fluoral and hydrogen fluoride with an aryl compound under anhydrous conditions. The purity of the 1,1, 1-trifluoro-2, 2-bisarylethane obtained can be raised by a simple purification method such as crystallization or distillation. The obtained 1,1,1-trifluoro-2,2-bisarylethane can be increased in purity by a simple purification method such as crystallization operation or distillation.

The present invention has the effect of making it possible to produce 1,1,1-trifluoro-2,2-bisarylethane efficiently by a simple procedure by condensing a mixture of fluoral and hydrogen fluoride with an aryl compound under anhydrous conditions. The purity of the 1,1, 1-trifluoro-2, 2-bisarylethane obtained can be raised by a simple purification method such as crystallization or distillation. The obtained 1,1,1-trifluoro-2,2-bisarylethane can be increased in purity by a simple purification method such as crystallization operation or distillation.

A polyimide which is obtained by a reaction of an aromatic diamine having a 1,1,1-trifluoro-2,2-ethanediyl group (—C(CF.sub.3)H—), as a linkage skeleton, with a tetracarboxylic dianhydride is easily dissolved in an organic solvent and exhibits excellent film forming properties. In addition, the thus-obtained polyimide can be used for an optical film and a display device.

A polyimide which is obtained by a reaction of an aromatic diamine having a 1,1,1-trifluoro-2,2-ethanediyl group (—C(CF.sub.3)H—), as a linkage skeleton, with a tetracarboxylic dianhydride is easily dissolved in an organic solvent and exhibits excellent film forming properties. In addition, the thus-obtained polyimide can be used for an optical film and a display device.