The purpose of the present invention is to provide: a π-conjugated compound exhibiting excellent light emission characteristics; an organic electroluminescent element using same; a display device; and an illumination device. Accordingly, this organic electroluminescent element is provided with: a positive electrode; a negative electrode; and at least one organic layer which is sandwiched between the positive electrode and the negative electrode, and which includes a light emission layer. The light emission layer includes a π-conjugated compound having a structure represented by any of general formulae (1)-(3) ##STR00001##
(in general formulae (1)-(3), at least one among R1-R4, R5-R8, and R9-R16 represents a group represented by general formula (4) ##STR00002##
(in general formula (4): Ar1 and Ar2 represent substituted or unsubstituted aryl groups; L1 represents a single bond or a substituted or unsubstituted arylene group; and # represents a bond to general formulae (1)-(3))).

A process for the preparation of an aromatic product is disclosed which includes a step b) of contacting one or more intermediate compounds with a further acid to form the aromatic product. The intermediate compounds can be obtained in step a) that includes contacting a 7-oxabicyclo[2.2.1]hept-2-ene core structure with an acidic mixture. The amount of acid in step b) is higher than the amount of acid in step a).

An anhydride compound, polyimide, and thin film are provided. The anhydride compound has a chemical structure of

##STR00001##

wherein R.sup.1 is

##STR00002##

each of R.sup.4 is independently C.sub.1-6 alkylene group, m is an integer of 0 to 10, and m′ is an integer of 1 to 10; n is an integer of 1 to 10, each of R.sup.2 is independently hydrogen, saturated or unsaturated C.sub.1-6 hydrocarbon group, CF.sub.3, silanol group, silyl group, or Al(OH).sub.3; and R.sup.3 is

##STR00003##

silanol group, silyl group, or Al(OH).sub.3. The anhydride compound can be reacted with a diamine compound to form a polyimide.

An anhydride compound, polyimide, and thin film are provided. The anhydride compound has a chemical structure of

##STR00001##

wherein R.sup.1 is

##STR00002##

each of R.sup.4 is independently C.sub.1-6 alkylene group, m is an integer of 0 to 10, and m′ is an integer of 1 to 10; n is an integer of 1 to 10, each of R.sup.2 is independently hydrogen, saturated or unsaturated C.sub.1-6 hydrocarbon group, CF.sub.3, silanol group, silyl group, or Al(OH).sub.3; and R.sup.3 is

##STR00003##

silanol group, silyl group, or Al(OH).sub.3. The anhydride compound can be reacted with a diamine compound to form a polyimide.

A method for producing an aromatic dianhydride includes reacting an aromatic diimide with a substituted or unsubstituted phthalic anhydride in an aqueous medium in the presence of an amine exchange catalyst to provide an aqueous reaction mixture including an N-substituted phthalimide, an aromatic tetraacid salt, and at least one of an aromatic triacid salt and an aromatic imide diacid salt. The method further includes removing the phthalimide from the aqueous reaction mixture by extracting the aqueous reaction mixture with an organic solvent in a first extractor for a first time period, at a first extraction temperature and subsequent to the first time period, extracting the aqueous reaction mixture with an organic solvent in a second extractor for a second time period, at a second extraction temperature. The aromatic tetraacid salt is converted to the corresponding aromatic dianhydride. Aromatic dianhydrides prepared according to the method are also described.

A method of making diimide and dianhydride that includes contacting a nitro or halo N-substituted phthalimide with bisphenol in polar aprotic solvents, such as dimethylsulfoxide and sodium hydride to provide high conversion to a diimide; precipitating the product in acetic acid solution and filtration; treating the resulting solid, N-substituted diimide with a carboxylic acid and substituted or unsubstituted dimethyl sulfoxide in an aqueous medium to provide a reaction mixture including tetra acid, triacid, imide diacid and diimide along with substituted or unsubstituted acetic acid, dimethyl sulfoxide and their derivatives. The method includes the isolation of tetra acid by precipitation in water followed by centrifuge or filtration. The tetra acid is converted into the corresponding dianhydride. The dianhydride prepared by the method are also described as precursor to make polyetherimide.

The present disclosure provides a process for the production of 4-azidosulfonylphthalic anhydride. In an embodiment, a process is provided and includes chlorinating 4-sulfophthalic acid trisodium salt (1), under solvent reaction conditions, to form a dissolved 4-chlorosulfonylphthalic anhydride (2) and an insoluble sodium chloride. The process includes first removing the insoluble sodium chloride from the dissolved 4-chlorosulfonylphthalic anhydride to form an isolated 4-chlorosulfonylphthalic anhydride. The process includes reacting, under solvent reaction conditions, the isolated 4-chlorosulfonylphthalic anhydride with sodium azide to form a dissolved 4-azidosulfonylphthalic anhydride and an insoluble sodium chloride. The process includes second removing the insoluble sodium chloride from the dissolved 4-azidosulfonylphthalic anhydride to form an isolated 4-azidosulfonylphthalic anhydride. The process includes retrieving a solid 4-azidosulfonylphthalic anhydride (3) from the isolated 4-azidosulfonylphthalic anhydride.

The present disclosure provides a process for the production of 4-azidosulfonylphthalic anhydride. In an embodiment, a process is provided and includes chlorinating 4-sulfophthalic acid trisodium salt (1), under solvent reaction conditions, to form a dissolved 4-chlorosulfonylphthalic anhydride (2) and an insoluble sodium chloride. The process includes first removing the insoluble sodium chloride from the dissolved 4-chlorosulfonylphthalic anhydride to form an isolated 4-chlorosulfonylphthalic anhydride. The process includes reacting, under solvent reaction conditions, the isolated 4-chlorosulfonylphthalic anhydride with sodium azide to form a dissolved 4-azidosulfonylphthalic anhydride and an insoluble sodium chloride. The process includes second removing the insoluble sodium chloride from the dissolved 4-azidosulfonylphthalic anhydride to form an isolated 4-azidosulfonylphthalic anhydride. The process includes retrieving a solid 4-azidosulfonylphthalic anhydride (3) from the isolated 4-azidosulfonylphthalic anhydride.

A benzene compound is prepared by reacting a furan compound to produce an unsaturated bicyclic ether having an unsaturated carbon-carbon bond; hydrogenating the unsaturated carbon-carbon bond in the unsaturated bicyclic ether to produce a saturated bicyclic ether; and dehydrating and aromatizing the saturated bicyclic ether to produce the benzene compound.

Embodiments of the present disclosure provide for an aromatic dianhydride, a method of making an aromatic dianhydride, an aromatic dianhydride-based polyimide, a method of making an aromatic dianhydride-based polyimide, and the like.