JP3473504B2 - Method for producing triphenylamine compound - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a triphenylamine compound, and more particularly to a method for producing a triphenylamine compound useful as a charge transport material (hole transport material) contained in an electrophotographic photoreceptor. is there.

[0002]

2. Description of the Related Art Conventionally, inorganic materials such as selenium (Se), cadmium sulfide (CdS), zinc sulfide (ZnS) and amorphous silicon (a-Si) have been used as photoconductive materials for photoconductors used in electrophotography. It has been known.
While these inorganic photoreceptors have many advantages, they also suffer from various drawbacks, such as being harmful, not being easy to dispose of, and being expensive. Therefore, in recent years, many organic photoconductors using organic substances that do not have these drawbacks have been proposed and put into practical use.

As a structure of these photoreceptors, a material that generates charge carriers (hereinafter referred to as a charge generating material) is used.
And a function-separated type photoconductor in which a charge receiving material and a material for transporting the charge carrier (hereinafter referred to as a charge transporting material) are provided in different layers, or a single layer type photoconductor in which these are provided in the same layer. The body etc. can be illustrated. Among these, the function-separated type photoconductor is widely used because of its wide selection of materials and high sensitivity.

As the charge transport material used in this function-separated type photoreceptor, a high molecular weight photoconductive compound such as polyvinylcarbazole is used, or a low molecular weight photoconductive compound is dispersed and dissolved in a binder polymer. is there. The polymer photoconductive compound alone has insufficient film-forming properties and adhesiveness, and plasticizers, binder polymers, etc. are added to improve these points. This may cause an increase in residual potential, which makes practical application difficult. On the other hand, a low-molecular weight photoconductive compound can easily provide a photoreceptor having excellent mechanical properties by appropriately selecting a binder polymer, but it cannot be said to be sufficient in terms of sensitivity.

For example, the diarylalkane derivative described in US Pat. No. 3,820,989 has few problems of compatibility with a binder polymer, but has poor stability to light and is used for electrophotography by repeating charging and exposure. When it is used in the photosensitive layer of the above-mentioned photoconductor, it has a drawback that the sensitivity of this photoconductor gradually decreases with repeated use. Further, the stilbene compound described in JP-A-58-65440 has relatively good charge retention and sensitivity,
The stability on repeated use is not satisfactory.

A monostyryltriphenylamine compound described in Japanese Patent Publication No. 63-019867 (exemplified as the following chemical formula (101)), Japanese Patent Publication No. 05-0426.
No. 61 and JP-A No. 62-120346, a distyryltriphenylamine compound (exemplified as the following chemical formula (102)), Japanese Patent Publication No. 06-093.
The tristyryltriphenylamine compounds (exemplified as the following chemical formula (103)) described in JP-A No. 124 and JP-A No. 63-163361 (exemplified as the following chemical formula (103)) have good charge retention and sensitivity, and also have stability in repeated use. It is good. However, the charge mobility is still insufficient, and it is not yet satisfactory as a charge transport material for high speed electrophotographic photoreceptors.

[0007]

[Chemical 3]

These compounds represented by the chemical formulas (101) to (103) have only one triphenylamine structure, which is a charge hopping site, represented by the following chemical formula (201) in one molecule. Absent. Therefore, there is a problem that sufficient photosensitivity cannot be obtained because sufficient charge mobility cannot be obtained. Although the above-mentioned publication describes that various substituents may be introduced into these compounds, introduction of a plurality of triphenylamines is not shown.

[0009]

[Chemical 4]

Introducing a plurality of triphenylamines,
To solve the above problem, Japanese Patent Application No. 09-002
There is a triphenylamine compound represented by the following general formula (2) described in Japanese Patent No. 844, etc.

[0011]

[Chemical 5] (Wherein, Ar ¹ to Ar ⁶ are substituents on .Ar ¹ to Ar ⁶ groups represents an phenyl group which may have a substituent, an alkyl group having a carbon number of 1 to 4, carbon atoms 1 To an alkoxy group having 1 to 4 carbon atoms, a dialkylamino group having 1 to 4 carbon atoms, and an alkylthio group having 1 to 4 carbon atoms, and these substituents may be substituted on the phenyl group. R ^{1 to} R ⁶ may be the same or different and may be the same or different.
^{7 ~R 12, R 15 ~R 20} , R 23 ~R 2 8 is from 1 to 4 carbon atoms
Alkyl group, alkoxy group having 1 to 4 carbon atoms, dialkylamino group having 1 to 4 carbon atoms, 1 to 4 carbon atoms
Is an alkylthio group and the substituents may be the same or different. R ¹³ , R ¹⁴ , R ²¹ , R ²² , R ²⁹ , R ³⁰
Represents a linear alkyl group having 1 to 4 carbon atoms and a linear alkoxy group having 1 to 4 carbon atoms, which may be the same or different. )

Such a triphenylamine compound represented by the above general formula (2) has hitherto been 4,4 ', 4 "-triformyltriphanylamine or 4,4', 4".
A tricarbonyl compound such as triacetyltriphenylamine and a phosphite ester which is an amino compound,
It was produced by condensing in a Wittig reaction in the presence of a base.

[0013]

However, in the above-mentioned method for producing a triphenylamine compound, a plurality of carbonyl groups are introduced into the tricarbonyl compound during the reaction process, and the phosphite is used as an intermediate. Had to do. In this case, it is often difficult to introduce a plurality of carbonyl groups into the tricarbonyl compound, and the phosphite is often unstable, so that the target triphenylamine compound cannot be efficiently obtained. It was difficult.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a production method capable of efficiently obtaining the triphenylamine compound represented by the general formula (2).

[0015]

The following method for producing a triphenylamine compound represented by the above general formula (2) is used as a method for solving the above problems. The first invention is represented by the following general formula (1):

[0016]

[Chemical 6] (R in the formula³¹ And R³² Is hydrogen or methyl group
It may be one or different. Ar⁷ And Ar⁸ Is replaced
Represents a phenyl group which may have a group, which may be the same or different.
You may Ar⁷And Ar⁸The substituents on the group are charcoal
Alkyl groups with a prime number of 1 to 4 and carbon atoms of 1 to 4
Coxy group, dialkylamino group having 1 to 4 carbon atoms, charcoal
Alkylthio groups having a prime number of 1 to 4
Groups may be substituted on the phenyl group, and the substituents
May be the same or different. R ³³~ R³⁸Has carbon number
An alkyl group of 1 to 4 and an alkoxy of 1 to 4 carbon atoms
Group, a dialkylamino group having 1 to 4 carbon atoms,
1 to 4 alkylthio groups, the substituents being the same
But it can be different. R³⁹, R⁴⁰Has 1 carbon
4 straight-chain alkyl group, straight-chain alkoxy having 1 to 4 carbon atoms
It represents a Si group and may be the same or different. X
Represents a halogen element. )

One or more halogen compounds represented by the formula (2) are characterized by reacting with ammonia.
Is a method for producing a triphenylamine compound. A second invention is a method for producing a triphenylamine compound according to the first invention, wherein the substituent X of the compound represented by the general formula (1) is a chlorine atom, a bromine atom or an iodine atom. is there. In a third invention, the compound represented by the general formula (1) is 4-chloro-4′-
(N, N-ditolylamino) stilbene, wherein the compound of the general formula (2) is 4,4 ′, 4 ″ -tris (4-
(N, N-ditolylamino) styryl) triphenylamine is the method for producing a triphenylamine compound according to the first invention.

A fourth invention is characterized in that, in any one of the first, second or third invention, a reaction catalyst is used when the halogen compound represented by the general formula (1) is reacted with ammonia. It is a method for producing a triphenylamine compound. 5th invention is a manufacturing method of the triphenylamine compound characterized by using a copper compound, or a palladium compound, or the mixture containing a copper compound and a palladium compound as said reaction catalyst in 4th invention. .

A sixth aspect of the present invention is the method for producing a triphenylamine compound according to any one of the first to fifth aspects, wherein the pressure during the reaction is atmospheric pressure. The seventh invention is characterized in that the pressure during the reaction is higher than the atmospheric pressure.
Is a method for producing a triphenylamine compound.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, one or more halogen compounds represented by the above general formula (1) (hereinafter sometimes simply referred to as halogen compound (1)) is reacted with ammonia. The method for producing a triphenylamine compound represented by the above general formula (2) (hereinafter sometimes simply referred to as a triphenylamine compound (2)).

The halogen compound (1) is obtained as shown below. First, the following general formula (3)
By reacting 4-halogenobenzyl halide represented by or 1-halogeno-4- (1-halogenoethyl) benzene represented by the following general formula (4) with triethyl phosphite, the following general formula (5) or A phosphite represented by the general formula (6) is obtained. (Reaction 1)

[0022]

[Chemical 7]

[0023]

[Chemical 8]

Next, the phosphite obtained by the reaction 1 and 4-diarylaminobenzaldehyde represented by the following general formula (7) or 4-diarylaminoacetophenone represented by the following general formula (8). React with. (Reaction 2)

[0025]

[Chemical 9]

At this time, 4 represented by the above general formula (3)
The substituent X in -halogenobenzyl halide or 1-halogeno-4- (1-halogenoethyl) benzene represented by the general formula (4) represents a halogen element, and chlorine, bromine and iodine are particularly desirable. The substituent Y represents a halogen element. The substituents X and Y may be the same or different.

The reaction 2 is carried out at room temperature or with heating in a suitable solvent under a base catalyst. Examples of the base catalyst include sodium methylate, sodium ethylate, alcoholate such as potassium t-butylate, sodium hydroxide, potassium hydroxide, sodium amide, sodium hydride and the like.

As the solvent, aromatic hydrocarbons such as toluene and benzene, alcohols such as methanol, ethanol and isopropyl alcohol, ethers such as dioxane and tetrahydrofuran, N, N-dimethylformamide and dimethyl sulfoxide can be used. . In particular, toluene and N, N-dimethylformamide are suitable. The amount of solvent is not particularly limited, and is 1 to 10
Double weight is sufficient. The reaction temperature in Reaction 2 is from room temperature to 100 ° C., preferably 2
It is between 0 and 70 ° C. After the completion of the reaction 2, the reaction solution is washed, extracted, dried, etc., and then the catalyst is removed by filtration, etc., and if necessary, recrystallization, column chromatography, distillation, etc. may be performed by known methods. Then, the obtained halogen compound (1) is purified.

The halogen compound (1) obtained as described above is reacted with ammonia (reaction 3).
As a result, the target triphenylamine compound (2) can be obtained. Generally, it is difficult to synthesize a tertiary amine such as a triphenylamine compound from ammonia, but as a result of examining the catalyst, the reaction temperature, and the reaction pressure, the present invention capable of proceeding the synthesis efficiently was obtained. It was The reaction conditions will be described below.

As the solvent used in the above reaction 3, various solvents such as aromatic solvents such as benzene and toluene, ether solvents such as diethyl ether and tetrahydrofuran can be used. As the reaction catalyst of the above Reaction 3, a copper catalyst or a palladium catalyst or a mixture of a copper catalyst and a palladium catalyst is preferable, and as the copper catalyst, copper powder, cuprous chloride, copper oxide or the like can be used. As the palladium catalyst, palladium chloride, palladium bromide, palladium acetate or the like can be used.
In addition, if necessary, potassium carbonate, sodium-t-
A base catalyst such as butoxide and an alkylphosphine catalyst such as tri-t-butylphosphine and tri-n-butylphosphine may be added to the initial catalyst.

The reaction temperature of the reaction 3 can be a wide range of temperatures from room temperature to the boiling point of the solvent, but it is preferable to carry out the reaction at a temperature of 70 ° C. or higher. Further, it is more preferable to carry out the reaction at or near the boiling point of the reaction solvent. Further, the reaction 3 is usually carried out at 1 atm, but when ammonia gas is used as ammonia, the reaction may be carried out under pressure conditions using an autoclave or the like.

After completion of the reaction 3, the reaction solution was washed with
After removing the solvent and excess ammonia by treatments such as extraction, drying, and filtration, the triphenylamine compound (2) obtained by the above Reaction 3 is taken out by column chromatography, crystallization, etc., if necessary. be able to.

According to such a production method, it is not necessary to introduce a plurality of carbonyl groups into triphenylamine, which was difficult in the conventional production method. Further, it is not necessary to pass through the phosphite as an intermediate. Therefore, the triphenylamine compound (2) can be obtained more efficiently than the conventional production method.

[0034]

EXAMPLES The present invention will now be described in detail with reference to examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. (Example 1) <1> Preparation of phosphite ester (shown in the following reaction formula (9)) First, a 200 ml eggplant-shaped flask equipped with a reflux condenser was set on a magnetic stirrer. Next, 20 g of 4-chlorobenzyl chloride (12
4 mmol) and then 25 g of triethyl phosphite
(150 mmol) was added. Next, the reaction liquid in this flask was heated in an oil bath and refluxed for 8 hours to react with stirring with a magnetic stirrer. Next, after completion of the reaction, unreacted triethyl phosphite was distilled off from the reaction solution in the flask while reducing the pressure with a pump.
Then, 30.9 g of phosphite was obtained as a residual content of the reaction liquid in the flask with a yield of 95%.

[0035]

[Chemical 10]

<2> Preparation of chlorine compound (the following reaction (1
0). ) First, 0.5 g (20 ml) of sodium hydride was placed in a 200 ml three-necked flask equipped with a drying tube and a dropping funnel.
And 50 ml of N, N-dimethylformamide were added to form a suspension, which was stirred with a magnetic stirrer. next,
5.0 g (19 mmol) of the phosphite obtained in <1> above was added to this flask, and the mixture was stirred at room temperature for 1 hour. Next, 5.7 g (19 g) of 4- (4 ′, 4 ″ -dimethyldiphenylamino) benzaldehyde was added to the dropping funnel.
15 ml of N, N-dimethylformamide (15 mmol) solution was added and reacted at 40 ° C. for 10 hours. After the reaction,
Water was added to the above reaction solution, and the mixture was extracted 3 times with toluene. Next, the extracted organic solution was washed with saturated saline until the aqueous layer became neutral, and then dried with magnesium sulfate.
Next, magnesium sulfate was removed from this solution by filtration, and the toluene solvent was distilled off under reduced pressure. And
The residue was recrystallized with a 7: 3 mixed solvent of toluene-ligroin to obtain 6.6 g of 4-chloro-4 ′-(N, N-ditolylamino) stilbene with a yield of 85%.

[0037]

[Chemical 11]

<3> Preparation of triphenylamine (represented by the following reaction formula (11)): Obtained by <2> in a 100 ml three-necked flask equipped with a Dimroth condenser equipped with an ammonia trap and a gas introduction tube. , 4-chloro-4 ′-(N, N-ditolylamino) stilbene 2.0 g (4.9 mmol) and sodium-t-butoxide 0.44 g (5.5 mmol), palladium acetate 0.11 g (0.5 mmol), Tri-t
-Butylphosphine 0.5 ml was added, and further 30 ml of o-xylene was added. And from the gas introduction pipe,
While introducing the ammonia gas into the three-necked flask, the reaction solution was vigorously stirred with a magnetic stirrer, and the reaction solution was heated using an oil bath, and reacted at 120 ° C. for 5 hours.

[0039]

[Chemical 12]

After the reaction was completed, the temperature of the reaction solution in the three-necked flask was returned to room temperature, and the reaction solution was added with 50 ml of 10% hydrochloric acid.
Washed once with 50 ml of water and three times with 50 ml of water. Next, this reaction solution was dried over magnesium sulfate, magnesium sulfate was removed from this solution by filtration, and the solvent was distilled off under reduced pressure. Then, in this filtrate, silica gel chromatography isolation was performed using a toluene solvent, and recrystallization was performed using a toluene-ligroin 7: 3 mixed solvent,
Yellow powder 0.1 g of 4,4 ′, 4 ″ -tris (4- (N, N-ditolylamino) styryl) triphenylamine
Was obtained with a yield of 5.3%.

<4> Example applied to the above electrophotographic photoreceptor of triphenylamine An undercoat layer (0.1 μm thick) made of methoxymethylated nylon (T-8, manufactured by Unitika Ltd.) on an aluminum substrate. Is formed on the undercoat layer,
A charge generation layer (0.1 μm thick) containing n-type titanyl phthalocyanine and polyvinyl butyral (BX-1 manufactured by Sekisui Chemical Co., Ltd.) was formed. Furthermore, 4,4 ′, 4 ″ -tris (4- (N,
A dichloroethane solution of N-ditolylamino) styryl) triphenylamine and polycarbonate (Mitsubishi Gas Chemical Co., Inc., Iupilon Z-200) (0.8: 1 weight ratio) was applied, and dried at 90 ° C. for 60 minutes to 20 μm. A thick charge transport layer was formed.

The coatability of this film was good, and a film having sufficient coating strength was obtained. The electrophotographic characteristics were evaluated by using a static electricity recording tester (EPA 8100) manufactured by Kawaguchi Denki Co., Ltd., after charging with corona discharge of −6 kV, followed by dark decay for 3 seconds to give 5 lux of white light. It was irradiated for a second, and the time (second) until the surface potential became 1/2 was obtained, and the half-exposure amount was obtained. In addition, the residual surface potential after irradiation with white light for 5 seconds was measured. As a result, the initial half-exposure amount was 0.238 (lux · sec) and the residual surface potential was −3 (volt).
It showed excellent photosensitivity. Further, the measured value after 1000 times was almost the same as the initial measured value with a half-exposure amount of 0.241 (lux · sec) and a residual surface potential of −5 (volt), which showed excellent repeated stability.

Example 2 A Dimroth cooling tube equipped with an ammonia trap and 100 ml of 3 equipped with a gas introduction tube.
In a necked flask, 4-chloro-4'- obtained from <2>
2.0 g of (N, N-ditolylamino) stilbene (4.
9 mmol) and 0.76 g (5.5 mm) of potassium carbonate
ol) and 0.49 g (0.5 mmol) of cuprous chloride, and further 30 ml of o-xylene. Next, while introducing ammonia gas into the three-necked flask from the gas introduction tube, the reaction solution was vigorously stirred with a magnetic stirrer, and the reaction solution was heated using an oil bath to react at 120 ° C. for 5 hours. It was After completion of the reaction, the same treatment as in Example 1 was performed to obtain 4,4 ′, 4 ″ -tris (4- (N, N-ditolylamino) styryl) triphenylamine in a yield of 4.8%. .

(Example 3) 4-chloro-4 '-(N, N
4-Bromo-4 '-(N, N-ditolylamino) stilbene 2.2 instead of -ditolylamino) stilbene
g (4.9 mmol) was used to carry out the same reaction as in Example 1 to obtain 4,4 ′, 4 ″ -tris (4- (N,
N-ditolylamino) styryl) triphenylamine was obtained with a yield of 10.3%.

Example 4 The reaction carried out in Example 1 was carried out in an autoclave, not in a flask, at a reaction pressure of 3
Under the reaction condition of 0 atm, 4,4 ', 4 "-tris (4-
(N, N-ditolylamino) styryl) triphenylamine was obtained with a yield of 11.2%.

4,4 ', 4 "-obtained in Examples 2 to 4
Using tris (4- (N, N-ditolylamino) styryl) triphenylamine, an electrophotographic photoreceptor was prepared in the same manner as in Example 1, and its half-exposure amount and residual surface potential were measured. was gotten.

[0047]

As described in detail above, the production method of the present invention enables efficient production of a triphenylamine compound useful as a charge transport material for high speed electrophotographic photoreceptors.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI C07C 323/35 C07C 323/35 G03G 5/06 313 G03G 5/06 313 // C07B 61/00 300 C07B 61/00 300 (56 ) References JP-A-11-279127 (JP, A) JP-A-11-343270 (JP, A) JP-A-7-330688 (JP, A) JP-A-5-255206 (JP, A) JP-A-5-206206 9-292724 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C07C 209/00 C07C 211/00 C07C 213/00 C07C 217/00 C07C 323/00

Claims (7)

(57) [Claims] 1. The following general formula (1) [Chemical 1] (R in the formula³¹ And R³² Is hydrogen or methyl group
It may be one or different. Ar⁷ And Ar⁸ Is replaced
Represents a phenyl group which may have a group, which may be the same or different.
You may Ar⁷And Ar⁸The substituents on the group are charcoal
Alkyl groups with a prime number of 1 to 4 and carbon atoms of 1 to 4
Coxy group, dialkylamino group having 1 to 4 carbon atoms, charcoal
Alkylthio groups having a prime number of 1 to 4
Groups may be substituted on the phenyl group, and the substituents
May be the same or different. R ³³~ R³⁸Has carbon number
An alkyl group of 1 to 4 and an alkoxy of 1 to 4 carbon atoms
Group, a dialkylamino group having 1 to 4 carbon atoms,
1 to 4 alkylthio groups, the substituents being the same
But it can be different. R³⁹, R⁴⁰Has 1 carbon
4 straight-chain alkyl group, straight-chain alkoxy having 1 to 4 carbon atoms
It represents a Si group and may be the same or different. X
Represents a halogen element. ) One or more halogens represented by
Characterized in that the compound is reacted with ammonia:
General formula (2) [Chemical 2] (In the formula, Ar¹ ~ Ar⁶ Is an optionally substituted group.
Represents a phenyl group. Ar¹~ Ar⁶Substituent on the group has carbon number
Is an alkyl group having 1 to 4 and an alkoxy group having 1 to 4 carbon atoms
Si group, dialkylamino group having 1 to 4 carbon atoms, carbon number
Is a 1 to 4 alkylthio group, and these substituents are
There may be multiple substitutions on the phenyl group,
May be the same or different. R¹ ~ R⁶ Is hydrogen
Represents a methyl group and may be the same or different. R
⁷~ R¹², R¹⁵~ R²⁰, R^{twenty three}~ R^{2 8}Has 1 to 4 carbons
Alkyl group, alkoxy group having 1 to 4 carbon atoms, carbon
A dialkylamino group having 1 to 4 carbon atoms, having 1 to 4 carbon atoms
Alkylthio group of, and those substituents may be the same or different.
You may R¹³, R¹⁴, R^{twenty one}, R^{twenty two}, R²⁹, R³⁰
Is a linear alkyl group having 1 to 4 carbon atoms, having 1 to 4 carbon atoms
4 are straight-chain alkoxy groups, each of which is the same or different
It may be. ) Triphenylamine compound
Manufacturing method. 2. The method for producing a triphenylamine compound according to claim 1, wherein the substituent X of the halogen compound represented by the general formula (1) is a chlorine atom, a bromine atom or an iodine atom. . 3. The halogen compound represented by the general formula (1) is 4-chloro-4 ′-(N, N-ditolylamino).
It is stilbene, and the triphenylamine compound represented by the general formula (2) is 4,4 ′, 4 ″ -tris (4-
(N, N-ditolylamino) styryl) triphenylamine, The manufacturing method of the triphenylamine compound of Claim 1 characterized by the above-mentioned. 4. The triphenylamine according to claim 1, wherein a reaction catalyst is used when reacting the halogen compound represented by the general formula (1) with ammonia. Method for producing compound. 5. The method for producing a triphenylamine compound according to claim 4, wherein a copper compound, a palladium compound, or a mixture containing a copper compound and a palladium compound is used as the reaction catalyst. 6. The method for producing a triphenylamine compound according to claim 1, wherein the pressure during the reaction is atmospheric pressure. 7. The method for producing a triphenylamine compound according to claim 1, wherein the pressure during the reaction is higher than atmospheric pressure.