An object of the present invention is to enable the synthesis of various fluorine-containing compounds having an organic group at both terminals of their tetrafluoroethylene structure (—CF.sub.2—CF.sub.2—). The present invention provides a fluorine-containing complex compound including a fluorine-containing organic metal compound represented by formula (1a):
R.sup.1—CF.sub.2—CF.sub.2-M.sup.1  (1a)
wherein M.sup.1 is a metal selected from the group consisting of copper, zinc, nickel, iron, cobalt, and tin; and R.sup.1 represents an organic group, and at least one ligand selected from the group consisting of pyridine ring-containing compounds and phosphines.

An object of the present invention is to enable the synthesis of various fluorine-containing compounds having an organic group at both terminals of their tetrafluoroethylene structure (—CF.sub.2—CF.sub.2—). The present invention provides a fluorine-containing complex compound including a fluorine-containing organic metal compound represented by formula (1a):
R.sup.1—CF.sub.2—CF.sub.2-M.sup.1  (1a)
wherein M.sup.1 is a metal selected from the group consisting of copper, zinc, nickel, iron, cobalt, and tin; and R.sup.1 represents an organic group, and at least one ligand selected from the group consisting of pyridine ring-containing compounds and phosphines.

The invention provides a material having a structure including three or more anthracene structures per molecule as a photosensitive unit. That structure allows the material to remain in a liquid state at room temperature due to its reduced crystallinity. After coated on an application member in a liquid state, it is irradiated with light from outside so that it can be cured by way of photocrosslinking, and when heated, it returns back to the original state as the linkage is cleaved. By use of this material it is possible to form a reversibly detachable layer that serves as an adhesive layer at an interface to an application member and a coating layer at the surface of the application member.

The invention provides a material having a structure including three or more anthracene structures per molecule as a photosensitive unit. That structure allows the material to remain in a liquid state at room temperature due to its reduced crystallinity. After coated on an application member in a liquid state, it is irradiated with light from outside so that it can be cured by way of photocrosslinking, and when heated, it returns back to the original state as the linkage is cleaved. By use of this material it is possible to form a reversibly detachable layer that serves as an adhesive layer at an interface to an application member and a coating layer at the surface of the application member.

In a process for producing a tetrabromophthalic diester composition, a liquid reaction mixture is prepared comprising tetrabromophthalic anhydride (TBPA), a C.sub.2 to C.sub.6 polyhydric aliphatic alcohol (PAA) and an alkylene oxide (AO) selected from the group consisting of ethylene oxide and propylene oxide, said reaction mixture being substantially free of an organic solvent. While agitating the reaction mixture, the temperature of the reaction mixture is raised to at least 50° C. to allow the TBPA to react with the PAA and AO to produce a diester composition. The reaction is terminated when the diester composition has an acid value equal to or less than 0.25 mg KOH/gm of the diester composition.

In a process for producing a tetrabromophthalic diester composition, a liquid reaction mixture is prepared comprising tetrabromophthalic anhydride (TBPA), a C.sub.2 to C.sub.6 polyhydric aliphatic alcohol (PAA) and an alkylene oxide (AO) selected from the group consisting of ethylene oxide and propylene oxide, said reaction mixture being substantially free of an organic solvent. While agitating the reaction mixture, the temperature of the reaction mixture is raised to at least 50° C. to allow the TBPA to react with the PAA and AO to produce a diester composition. The reaction is terminated when the diester composition has an acid value equal to or less than 0.25 mg KOH/gm of the diester composition.

In a process for producing a tetrabromophthalic diester composition, a liquid reaction mixture is prepared comprising tetrabromophthalic anhydride (TBPA), a C.sub.2 to C.sub.6 polyhydric aliphatic alcohol (PAA) and an alkylene oxide (AO) selected from the group consisting of ethylene oxide and propylene oxide, said reaction mixture being substantially free of an organic solvent. While agitating the reaction mixture, the temperature of the reaction mixture is raised to at least 50° C. to allow the TBPA to react with the PAA and AO to produce a diester composition. The reaction is terminated when the diester composition has an acid value equal to or less than 0.25 mg KOH/gm of the diester composition.

The present invention provides a tetracarboxylic acid diester compound shown by the following general formula (1),

##STR00001##

wherein X.sub.1 represents a tetravalent organic group; and R.sub.1 represents a group shown by the following general formula (2),

##STR00002##

wherein the dotted line represents a bond; Y.sub.1 represents an organic group with a valency of k+1; “k” represents 1 or 2; and “n” represents 0 or 1. There can be provided a tetracarboxylic acid diester compound that can give a polyimide precursor polymer soluble in a safe organic solvent widely used as a solvent of a composition and usable as a base resin of a photosensitive resin composition.

A preparation method according to the present invention makes it possible to industrially produce large amounts of highly pure optically active tert-butyl 3-methyl-4-oxopiperidine-1-carboxylate in high yield by use of commercially available reagents and solvents. In addition, the use of novel intermediates according to the present invention makes it possible to produce highly pure optically active tert-butyl 3-methyl-4-oxopiperidine-1-carboxylate in high yield.

A preparation method according to the present invention makes it possible to industrially produce large amounts of highly pure optically active tert-butyl 3-methyl-4-oxopiperidine-1-carboxylate in high yield by use of commercially available reagents and solvents. In addition, the use of novel intermediates according to the present invention makes it possible to produce highly pure optically active tert-butyl 3-methyl-4-oxopiperidine-1-carboxylate in high yield.