JP3132784B2 - Method for producing 3,3'-dinitro-5,5'-bis (trifluoromethyl) diphenyl ether - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to 3,3'-dinitro-
5,5'-bis (trifluoromethyl) diphenyl-
The present invention relates to a method of manufacturing a tell. 3,3′-Dinitro-5,5′-bis (trifluoromethyl) diphenyl ether is useful as a starting material for polyimide, polyamide, polyamideimide, bismaleimide or epoxy resin. It is an intermediate of 5,5'-bis (trifluoromethyl) diphenyl ether.

[0002]

2. Description of the Related Art In recent years, with the development of electronics, research and development of insulating materials for a multilayer circuit board have been widely pursued. Among organic materials, polyimide is particularly promising as a low-dielectric material because it has excellent heat resistance and dimensional stability, and has a lower dielectric constant than inorganic materials. However, with higher integration of electronic circuits, materials having a lower dielectric constant are desired.

As a technique for lowering the dielectric constant of polyimide, it is known to introduce fluorine into a molecular unit of polyimide. For such a purpose, an aromatic diamine containing a hexafluoroisopropylidene group (EP Publication 299,
No. 865) is disclosed. However, these aromatic diamines have a multi-step synthesis method,
There is an industrial problem such as insufficient heat fluidity when molding polyimide resin obtained therefrom. For this reason, a polyimide having a low dielectric constant and excellent in moldability has been desired.

As a means for improving the moldability, it is also effective that the substitution position of the amino group in the aromatic nucleus is at the meta position with respect to the bonding group and that the amino group is linked by an ether group. ing. For this reason, for example, a polyimide having 3,3'-diamino-5,5'-bis (trifluoromethyl) diphenyl ether as a monomer unit has a low dielectric property and excellent moldability. Can be expected. Regarding the method for producing the dinitro compound which is a precursor thereof, see US Pat.
670 discloses a method for condensing 3,5-dinitrotrifluoromethylbenzene in the presence of water and a base.

[0005] In this method, as a first step of the reaction,
One nitro group of 3,5-dinitrotrifluoromethylbenzene was hydrolyzed by water in the presence of a base, and as a second step, 3,5-dinitrotrifluoromethylbenzene was obtained in the first step. Condensation of the phenol derivative with the phenoxide anion generated by the base gives the desired product 3,3'-dinitro-5,5'-bis (trifluoromethyl) diphenyl ether. However, 3,5-case dinitro trifluoromethylbenzene, less active because the nitro group is relative in the meta position, OH of the first stage a is nitro group of the reaction ^- the nucleophilic substitution reaction with a large energy The patent describes that a reaction at a temperature of 160 ° C. for 24 hours is required. Further, in this method, it is predicted that a phenol compound or an azoxy compound is produced as a by-product, and a purification step such as recrystallization is required.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide 3,3 'which is very promising as a raw material for low dielectric polyimide.
3,3'-dinitro- which is a precursor of diamino-5,5'-bis (trifluoromethyl) diphenyl ether
5,5'-bis (trifluoromethyl) diphenyle-
It is an object of the present invention to provide a method for producing ter by an industrially advantageous method and at a high yield under reaction conditions in which side reactions are suppressed.

[0007]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, completed the present invention. That is, the present invention provides a compound represented by the formula (2) by subjecting 3,5-dinitrotrifluoromethylbenzene represented by the formula (1) to a self-condensation reaction in an aprotic polar solvent in the presence of a nitrite. ) (Formula 4)
The present invention relates to a method for producing 3′-dinitro-5,5′-bis (trifluoromethyl) diphenyl ether.

[0008]

Embedded image

[0009]

Embedded image

According to the production method of the present invention, 3,5-dinitrotrifluoromethylbenzene is used as a raw material, which has a trifluoromethyl group and the substitution position of the nitro group and the bonding group is bonded at the meta position. 3'-dinitro-
5,5′-bis (trifluoromethyl) diphenyl ether can be synthesized in one step. This dinitro compound can be quantitatively derived to the corresponding diamine by reduction.

According to the production method of the present invention, as the first stage of the reaction, NO ₂ nitro groups of a 3,5-dinitro trifluoromethylbenzene the raw material is generated from nitrite
^- receiving the attack, after passing through an intermediate of formula (3),
A reaction mechanism for removing N ₂ O ₃ to generate a phenoxide anion represented by Formula (4) (Formula 5) is considered.

[0012]

Embedded image

The phenoxide anion thus produced is immediately reacted with another molecule of 3,5-dinitrotrifluoromethylbenzene to give 3,3'-dinitro-
Produces 5,5'-bis (trifluoromethyl) diphenyl ether. In this case, it is extremely advantageous that NO ₂ ⁻ formed by condensation of the phenoxide anion with 3,5-dinitrotrifluoromethylbenzene is converted into another 3,5-
Attacks dinitrotrifluoromethylbenzene and generates phenoxide anion. For this reason, the nitrite added at the beginning of the reaction may be a catalytic amount. In addition, in the method of the present invention, phenoxide anions are directly produced without going through a phenol intermediate, so that no by-products are produced.

Regarding the reaction mechanism, for example, Jour
nal of Organic Chemistry, 42 No. 21,3431 to 3434 and 4
-Condensation of nitrophthalimide with nitrite. Condensation of 3,5-dinitrotrifluoromethylbenzene, which is the production method of the present invention, differs from the above-mentioned method in that both the starting material and the target substance are dinitro compounds, and thus the produced 3,3′-dinitro-5,5 '-Bis (trifluoromethyl) diphenyl ether was further attacked by the phenoxide anion, and it was expected that trinuclear or higher polynuclear substances were formed as impurities. However, the present inventors have studied the reaction in detail, and surprisingly found that, in the condensation of 3,5-dinitrotrifluoromethylbenzene, the starting material 3,5-dinitrotrifluoromethylbenzene was Since the reactivity of the target product, 3,3'-dinitro-5,5'-bis (trifluoromethyl) diphenyl ether, is greatly different, it was found that formation of impurities such as trinuclear bodies hardly occurred.

The 3,3'-dinitro-5 of the present invention will now be described.
The method for producing 5′-bis (trifluoromethyl) diphenyl ether will be specifically described. This compound has 3,5-
It can be produced in high yield by subjecting dinitrotrifluoromethylbenzene to a self-condensation reaction in the presence of nitrite in an aprotic polar solvent. 3,5- used in the present invention
Dinitrotrifluoromethylbenzene is produced by nitrating trifluoromethylbenzene in a conventional manner. As the nitrite used in the method of the present invention, potassium nitrite, sodium nitrite, calcium nitrite, magnesium nitrite, lithium nitrite, ammonium nitrite and the like are preferably used, and nitrites of other metals can also be used. The amount of the nitrite used is 0.01 to 5 times, preferably 0.1 to 2 times the mole of 3,5-dinitrotrifluoromethylbenzene as the raw material.

The aprotic polar solvent used in the method of the present invention includes formamide, N-methylformamide, N, N-dimethylformamide, N, N-diethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone , 1,3-dimethyl-2-imidazolidinone, dimethylsulfoxide, sulfolane and the like. The amount of these solvents used is not particularly limited, but is usually 1 to 10 times the weight of the raw materials. In the method of the present invention, when water is present in the reaction solvent, the generated phenoxide anion is hydrolyzed to form a phenol derivative. Therefore, the reaction is preferably performed under anhydrous conditions. In the method of the present invention, in order to promote the reaction, a phase transfer catalyst such as copper powder and a copper-based compound or crown ether, polyethylene glycol, quaternary ammonium salt, or quaternary phosphonium salt may be used as a catalyst. Absent.

[0017] The reaction temperature is usually 100 to 230 ° C, preferably 120 to 200 ° C. Reaction time is 1 to 30
Time. As a general reaction method of the present invention, a predetermined amount of a raw material may be added to a solvent and reacted at a predetermined temperature. In some cases, an azeotropic dehydration solvent such as benzene, toluene, or xylene may be added, and the temperature may be raised while dehydrating to react. The end point of the reaction can be determined by thin layer chromatography or high performance liquid chromatography while observing the reduction of the raw materials.

After completion of the reaction, the mixture is discharged into water or the like after concentration or as it is, and crude 3,3'-dinitro-
5,5'-bis (trifluoromethyl) diphenyl ether is obtained. This can be purified by recrystallization or sludge with a solvent such as alcohol.

[0019]

EXAMPLES Hereinafter, the method of the present invention will be described in more detail by way of examples, but the present invention is not limited thereto. Example 1 A flask equipped with a stirrer, a thermometer and a reflux condenser was charged with 3,5-dinitrotrifluoromethylbenzene 3
5.7 g (0.151 mol), sodium nitrite 1
6.6 g (0.242 mol) and 300 ml of 1,3-dimethyl-2-imidazolidinone were added, and the mixture was heated while stirring while passing nitrogen gas, and reacted at 130 ° C. for 10 hours. After completion of the reaction, the content was discharged into 1 liter of water, and the precipitated solid was filtered, dried, and crude 3,3′-
Dinitro-5,5'-bis (trifluoromethyl) diphenyl ether 35.8 g (yield 60%, purity 90%)
I got This was sludged with 60 g of methanol to obtain a pale yellow crystal having a purity of 99%. Melting point 121-122.5 ° C ¹ H-NMR δ (CDCl ₃ , ppm) 7.65 (2H, S (br), 6 and 6′-H) 8.05 (2H, S (br), 2 and 2) '-H) 8.35 (2H, S (br), 4 and 4'-H) elemental analysis _{(C 14 H 6 N 2 O} 5 F 6) C H N F calculated (%) 42.44 1. 53 7.07 28.77 Observed value (%) 42.34 1.54 7.01 28.71

Example 2 The same apparatus as in Example 1 was equipped with a water separator, and 35.7 g of 3,5-dinitrotrifluoromethylbenzene (0.15 g) was used.
1 mol), 15 g of calcium nitrite monohydrate (0.1
0 mol), 30 ml of toluene and 300 ml of 1,3-dimethyl-2-imidazolidinone were added, and the mixture was heated with stirring while passing nitrogen gas. In the reflux state of toluene, water azeotropically removed was removed from the system by a water separator. After performing azeotropic dehydration, the temperature was raised while distilling off toluene, and the reaction was carried out at an internal temperature of 140 ° C. for 10 hours. After completion of the reaction, the content was discharged into 1 liter of water, and the precipitated solid was filtered and dried, and 32.8 g of crude 3,3′-dinitro-5,5′-bis (trifluoromethyl) diphenyl ether was obtained.
(Yield 55%, purity 88%) was obtained.

Example 3 In Example 1, N, N-dimethylformamide was used as a solvent, and the reaction was carried out in the same manner as in Example 1 at a reaction temperature of 150 ° C. to obtain crude 3,3′-dinitro-5,5 ′. -Bis (trifluoromethyl) diphenyl ether 29.8 g
(Yield 50%, purity 89%) was obtained. Example 4 Example 1 except that 20.6 g of potassium nitrite and 0.5 g of 18-crown-6-ether were used as catalyst.
And the reaction was carried out in the same manner as described above.
-Bis (trifluoromethyl) diphenyl ether 3
7.6 g (63% yield, 91% purity) were obtained.

[0022]

The present invention provides a method for producing a novel aromatic nitro compound in high yield. The aromatic diamine obtained from this compound is useful as a raw material for polyimide and the like having a low dielectric constant and excellent moldability.

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-5-170735 (JP, A) JP-A-5-85990 (JP, A) JP-A-4-312544 (JP, A) JP-A-3-3 89353 (JP, A) JP-A-3-83952 (JP, A) "Journal of Organic Chemistry," 1977, Vol. 42, No. 21, pages 3431-3434 (58) Fields investigated (Int. Cl. ⁷ , DB name) C07C 205/38 C07C 201/12 CA (STN) REGISTRY (STN)

Claims (1)

(57) [Claims] 1. A 3,5-dinitrotrifluoromethylbenzene represented by the formula (1): ## STR1 ## Is subjected to a self-condensation reaction in the presence of a nitrite in an aprotic polar solvent, characterized in that 3,3′-dinitro-5,5′-bis ( A process for producing (trifluoromethyl) diphenyl ether. Embedded image