JPS614765A - Novel disazo compound and production thereof - Google Patents

Abstract

NEW MATERIAL:Disazo compounds of formula I, wherein A is a group of formula II, III or IV (wherein R is alkyl, alkoxy, nitro, halogen, cyano, halomethyl; n is an integer of 0-3). USE:Charge generating materials for electrophotographic materials (particularly, laminated type). The compds. have higher sensitivity than that of conventional disazo compds. and are superior in image reproducibility even for red copies. PREPARATION:A diamino compd. is diazotized with sodium nitrite in an inorg. acid. The resulting tetrazonium compd. of formula VI (wherein X is an anion functional group) is coupled with a compd. corresponding to a group of formula II, III or IV.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel disazo compound useful as a charge-generating pigment in an electrophotographic photoreceptor, particularly a laminated electrophotographic photoreceptor, and a method for producing the same.

BACKGROUND ART It has been known that certain disazo compounds are useful as charge-generating pigments used in charge-generating layers of laminated photoreceptors, which are one form of electrophotographic photoreceptors. The layered photoreceptor referred to herein means that a charge-generating pigment having the ability to generate charge carriers by light is applied onto an isoelectric support by an appropriate method such as vacuum evaporation, coating of a pigment solution, or coating of a resin solution with a charge-generating pigment. A charge generation layer is formed as a thin layer by coating a dispersion liquid containing fine particles, and a charge transport layer (usually this charge carrier) is used to efficiently inject and move the charge carriers generated in the charge generation layer. The transport layer is a photoreceptor on which a charge transporting substance and a binder resin are formed. Conventionally, disazo compounds used in this type of photoreceptor have been described in, for example, JP-A-47-37543 and JP-A-52-55643 (/didiy-based disazo compounds or JP-A-52-55643). Showa 52
Stilbene-based disazo compounds described in JP-A-8832 are known. However, conventional laminated photoreceptors using disazo compounds generally have low sensitivity, and the visible wavelength range is approximately 450 to 700.
nm, and considering this photosensitive wavelength characteristic, the image reproducibility of red originals was poor. Therefore, when this photoreceptor is mounted, there is a disadvantage in the design of the copying machine because it is necessary to use a filter that cuts red light.

Purpose The purpose of the present invention is to provide an electrophotographic photoreceptor, in particular, when 8 is used as a charge generating material in a layered electrophotographic photoreceptor, the sensitivity is higher than that of conventional disazo compounds, and the photosensitive wavelength range in the visible region is short. It is an object of the present invention to provide a disazo compound that has excellent image reproducibility even for red originals because it is limited to the wavelength side (approximately 450 to 600 nm), and a method for producing the same.

Structure One of the aspects of the present invention is a novel disazo compound represented by the following general formula (I).

or, where R represents an alkyl group, an alkoxy group, a nitro group, a halogen, a cyano group, or a halomethy/I/ group, and n is an integer of 0, 1, 2, or 3, and n is 2 or 3. R may be the same or different groups. ). ] Another aspect of the present invention is to diazotize the diamino compound represented by formula (II) to obtain a tetrazonium salt represented by the general formula (button (in the formula, X represents an anionic functional group), a salt and the following general formula, (V) or ■ (wherein R is an alkyl group, an alkoxy group, a nitro group, a halogen, a cyano group or) -
represents a methyl group, n is an integer of o, x, 2 or 3, and when n is an integer of 2'f or 3, R
may be the same or different groups. ) (hereinafter referred to as a coupler) is a method for producing a novel disazo compound represented by the general formula (I).

To explain in more detail the method for producing the disazo compound of the present invention, first, diazotization of a diamino compound according to the formula (1) is carried out by converting the diamino compound into a mixture of sodium nitrite at -10°C in an inorganic acid such as hydrochloric acid or sulfuric acid. The diazotization reaction is completed in about 30 minutes to 3 hours.Additionally, for example, hydrofluoroboric acid or an aqueous sodium borofluoride solution is added to the reaction mixture to form a tetrazonium salt. It is preferable to precipitate the tetrazonium salt, collect the crystals, and then use them in the next reaction.Then, this tetrazonium salt is treated with the general formula G.
V), (V) and (V) are reacted to cause a coupling reaction.In practice, this reaction is carried out using N,N-dimethylformamide (DMF), dimethyl sulfoxide, etc. The tetrazonium salt and the coupler are mixed and dissolved in an organic solvent, and an aqueous alkali solution such as an aqueous sodium acetate solution is added dropwise thereto at about -1θ°C to 40°C.

This reaction is complete in approximately 5 minutes to 3 hours. After completion of the reaction, one of the precipitated crystals is taken and purified by an appropriate method (for example, washing with water and/or an organic solvent, recrystallization method, etc.) to complete the production of the disazo compound.

The novel disazo compound of the present invention obtained as described above is a colored crystal at room temperature, and specific examples thereof are shown in Tables 1 and 2 below, along with melting points, elemental analysis values, and infrared absorption spectrum data. .

(Left below) These disazo compounds are useful as charge-generating substances for laminated electrophotographic photoreceptors as mentioned above, but in addition,
Used as a charge generating substance in an electrophotographic photoreceptor having a single-layer photosensitive layer in which a charge generating substance and a charge transporting substance are dispersed in a resin, and also having a photosensitive layer in which a photoconductive substance is dispersed in a resin. It is also useful as a photoconductive material that can be used in electrophotographic photoreceptors.

The present invention will be explained below by way of examples.

Example 1 Preparation of tetrazonium salt 2.6-bis(4-aminope/zylidene)-4-methylcyclohexanone 15.91i1 (0.05 mol),
To a mixture of 36% hydrochloric acid xooml and water
Nitrous acid made by dissolving 0.05 mol) in 30 ml of water
After adding the IJum aqueous solution dropwise at a temperature of 0 to 5°C, the mixture was further stirred at this temperature for 1 hour. This solution was thoroughly filtered to remove insoluble materials, and 42% hydrofluoric acid was added to the lachrymal fluid, and the precipitated crystals were filtered, washed with water, washed with methanol, and dried to obtain a tetrazonium salt. Yield 21.5.9 (83.5%).

Infrared absorption spectrum (KBr disk) νshi 22
60 cm-" νC=O1670cIrL Preparation of disazo compound AI The above tetrazonium salt 1.29 Ii and 2-hydroxy-3-naphthoic acid anilide 1.
3z 11 (twice the mole of the tetrazonium salt) was dissolved in 150 g of cooled N,N-dimethylformamide, and a solution consisting of 0.82 N sodium acetate and 7 g of water was added to it at 5 to 10°C. The mixture was added dropwise at room temperature for 20 minutes, and after cooling was stopped, the mixture was further stirred at room temperature for 3 hours.

After that, the generated precipitate was collected and N heated to 80°C.
Washed 3 times with 200 min of N-dimethylformamide, then washed 2 times with 200 min of water, and washed with 2++ unHy at 80°C.
The disazo compound 1.419 (yield: 65.0%) of the compound Al shown in Table 1 was obtained. This disazo compound appeared as a reddish-purple powder, and its infrared absorption spectrum (KBr disk) was shown in FIG.

Examples 2 to 16 (Production of disazo compounds A2 to 16) In the production of the disazo compound of compound A1 in Example 2, the same method as in Example 1 was used except that the compounds in Table 3 below were used as coupling components. Disazo compounds of Compounds A2 to 16 shown in Tables 1 and 2 were manufactured. These results are also shown in Table-3.

Effects As described above, the novel disazo compound of the present invention is particularly useful as a charge generating substance in a laminated electrophotographic photoreceptor, and in order to clarify this point, specific application examples are shown below. Furthermore, in order to clarify the inventive step of the present invention,
A comparison with conventional disazo compounds is also shown.

Example of use 76 parts by weight of the disazo compound AA16 of the present invention, 260 parts by weight of a tetrahydro 7 run solution (solid content 9% 2%) of polyester resin (Vylon 200 manufactured by Toyobo Co., Ltd.), and 3700 parts by weight of tetrahydrofuran were mixed into i-lumil. The resulting dispersion was applied using a doctor blade onto the aluminum surface of an aluminum-deposited polyester paste (conductive support), air-dried,
A charge generation layer having a thickness of about 1 μm was formed. On the other hand, 9-ethylcarbazole-3-aldehyde-1-methyl-1-phenylhydrazone 2Mk part, polycarbonate resin ()
2 parts by weight of Gunlite Kl 300 (manufactured by Teijin Kasei Ltd.) and 16 parts by weight of tetrahydrofuran were mixed and dissolved to form a solution, which was applied onto the charge generation layer using a doctor blade and heated at 80°C for 2 minutes and then at 100°C. The mixture was dried for 5 minutes to form a charge transport layer having a thickness of about 20 μm, thereby producing a laminated photoreceptor (A) shown in FIG.

For comparison, following the procedure for producing the photoreceptor described above, instead of the disazo compound of the present invention,
4,4'-bis(2-hydroxy-3-phenylcarbamoyl-1-naphthylazo)-3,3, which is a be/zidine-based disazo compound disclosed in JP-A-37543 and JP-A-52-55643. '-dichlorodiphenyl and ■ 4,4'-bis(2-hydroxy-3-phenylcarbazoyl-1-naphthylazo)stilbene, which is a stilbene-based disazo compound described in JP-A-52-8832. A photoreceptor (B) and a photoreceptor (C) were prepared in exactly the same manner except that the photoreceptor (C) was used.

The electrostatic properties of the photoreceptors (A), (B), and (C) thus prepared were tested using a commercially available electrostatic copying paper tester (5p-4zs type, manufactured by Kawaguchi Electric Co., Ltd.). It was measured. That is, first, a 16KV corona discharge is applied to the photoreceptor for 20? The surface potential at that time was measured to be Vd.

(volt) was determined, the sample was allowed to decay in the dark for 20 seconds, and the surface potential at that time was measured and determined as Vpo (volt). Next, the photosensitive layer is irradiated with light from a tungsten lamp so that the surface becomes 4°5 lux, and the time (seconds) until the surface potential reaches 172 of V po
was determined, and the exposure amount was set as El/2 (lux 0 seconds). Similarly, the exposure amount E115 (lux-seconds) and El/10 (lux-seconds) were determined by determining z/s of V p o and the time (seconds) until it became 1/10. Table this result.
4.

As is clear from the results in Table 4, photoreceptor (A) using the disazo compound of the present invention has extremely high sensitivity compared to photoreceptors (B) and (C) using conventional disazo compounds. I understand.

[Brief explanation of the drawing]

1 to 16 are infrared absorption spectra of typical disazo compounds of the present invention (KBr disc). 22 is an aluminum vapor deposited film, 33 is a charge generation layer, and 44 is a charge transport layer.

Claims (1)

[Claims] 1. General formula (I) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [In the formula, A is ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ or ▲ There are mathematical formulas, chemical formulas, tables, etc. , when n is an integer of 2 or 3, R may be the same or different groups. ] A novel disazo compound represented by 2. Formula (II) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ The diamino compound represented by is diazotized to form the general formula III ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, X represents an anionic functional group. ) This tetrazonium salt and the general formula (IV), (V) or (VI) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (IV) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ ( V) ▲Mathematical formulas, chemical formulas, tables, etc.▼(VI) (In the formula, R represents an alkyl group, an alkoxy group, a nitro group, a halogen, a cyano group, or a halomethyl group, and n is 0, 1, 2, or 3. is an integer, and when n is an integer of 2 or 3, R may be the same or different groups.General formula (I) characterized by reacting with a compound represented by ▲Formula , chemical formulas, tables, etc. ▼ [In the formula, A is ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ or ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (R and n are As described above.) A method for producing a novel disazo compound represented by.