JPS637220B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel disazo compound and a method for producing the same. BACKGROUND ART Inorganic photoreceptors using inorganic photoconductive materials such as selenium, cadmium sulfide, and zinc oxide have been widely used in electrophotography. ``Electrophotography'' generally refers to a method in which a photoconductive photoreceptor is first charged in a dark place by corona discharge, etc., and then subjected to imagewise exposure to selectively discharge the charges in the exposed areas, leaving the unexposed areas free of electrostatic charge. This is one of the image forming methods in which an image is left behind and this latent image is visualized by a developing means using toner or the like to form an image. The basic characteristics required of the photoreceptor used in such electrophotography are (1) ability to be appropriately charged in the dark, (2) excellent charge retention in the dark, and ability to discharge the charge. (3) high photosensitivity and rapid discharge of charges upon irradiation with light; and excellent mechanical strength and flexibility. Although the conventional inorganic photoreceptors have several advantages, they also have various disadvantages. For example, the selenium photoreceptors currently widely used are (1) to
Although the condition (3) is satisfied to a considerable extent, the mechanical strength and flexibility are not satisfactory. In particular, as a variety of processes have been adopted in recent electrophotography methods, photoreceptors that are compatible with all of these processes have become required, and for example, flexible shapes are required. However, the selenium photoreceptor has low flexibility and is difficult to produce in such a shape. Similar drawbacks can also be cited for inorganic photoreceptors other than selenium photoreceptors. In recent years, in order to eliminate the drawbacks of these inorganic photoreceptors, organic electrophotographic photoreceptors using various organic photoconductive materials have been researched and developed, and have been put into practical use. For example, poly-N-vinylcarbazole and 2,4,7-trinitrofluorene-9 are coated on a support.
Photoreceptor with a photosensitive layer containing poly-N-vinylcarbazole sensitized with a pyrylium salt dye (see U.S. Pat. No. 3,484,237) 25658), a photoreceptor with a photosensitive layer containing an organic pigment as the main component (see JP-A-47-37543), a photoreceptor with a photosensitive layer containing a eutectic complex consisting of a dye and a resin as the main component. Examples include a photoreceptor (see Japanese Unexamined Patent Publication No. 10735/1983). Although these organic photoreceptors have improved the mechanical properties and flexibility of the inorganic photoreceptors to some extent, they generally have low photosensitivity and do not fully satisfy the requirements for electrophotographic photoreceptors. In general, the characteristics of the electrophotographic photoreceptor are greatly influenced by the material used, the manufacturing method, etc., but in particular the photoconductive material has a large influence. For this reason, research into photoconductive materials has been actively conducted, and the present invention also relates to this. An object of the present invention is to provide a novel disazo compound which is particularly useful as a photoconductive material and which solves the drawbacks of the conventional photoconductive materials for photoreceptors, and furthermore, to provide a method for producing the compound. It is to provide. That is, one of the aspects of the present invention is the general formula [However, A is

[Formula] or

[Formula] (R is a lower alkyl group, a lower alkoxy group, a nitro group, a di-lower dialkylamino group, or a halogen; n is an integer of 0, 1, 2, or 3, and when n is an integer of 2 or 3; (R may be the same or different groups). ] This is a novel disazo compound. The invention also relates to the general formula [However, X represents an anionic functional group. ] and the general formula

[Formula] or

[Formula] [However, R is a lower alkyl group, a lower alkoxy group, a nitro group, a di-lower dialkylamino group, or a halogen, n is an integer of 0, 1, 2, or 3, and n is an integer of 2 or 3. In some cases, they may be the same or different groups. ] (hereinafter referred to as a coupling component) to provide a method for producing the novel disazo compound of the present invention represented by the above general formula. The novel disazo compound of the present invention is a colored crystal at room temperature, and specific examples thereof are shown in the table below along with melting point, elemental analysis values, and infrared absorption spectrum data.

【table】

【table】

【table】

[Table] The novel disazo compound of the present invention can be obtained by reacting a tetrazonium salt represented by the above general formula with a coupling component. Tetrazonium salts include, for example, 1,4-bis(2-nitrostyryl)benzene. is reduced to 1,4-bis(2-aminostyryl)
benzene can be obtained by further diazotization. 1,4-bis(2-nitrostyryl)benzene is produced by the Wittig reaction or J.Am.Chem.Soc., 83,
1733 (1961), the so-called Wadsworth et al.
Obtained by Wittig-Horner reaction. 1,4-bis(2-aminostyryl)benzene can then be obtained by reducing this nitro compound in an organic solvent such as N,N-dimethylformamide using a reducing agent such as iron-hydrochloric acid. This reduction reaction is completed in 30 minutes to 2 hours at a reaction temperature of 70 to 120°C. The diamino compound thus obtained is diazotized by adding it to a dilute inorganic acid such as dilute hydrochloric acid or dilute sulfuric acid, and then adding an aqueous solution of sodium nitrite to this.
This is done by adding at 10°C to 10°C. This diazotization reaction is completed in 30 minutes to 3 hours. In this case, it is desirable to add, for example, borohydrofluoric acid to the reaction mixture to precipitate the tetrazonium salt, followed by filtration to obtain crystals. Next, the above-mentioned coupling component is added to the obtained tetrazonium salt in a molar amount of 1 to 10 times, preferably 2 to 10 times the mole of the tetrazonium salt.
A coupling reaction is caused by adding 5 times the molar amount. In reality, this reaction is carried out by mixing and dissolving the tetrazonium salt and the coupling component in an organic solvent such as N,N-dimethylformamide or dimethyl sulfoxide, and adding an alkali solution such as an aqueous sodium acetate solution to the mixture at about -10°C to 10°C. This is done by dropping an aqueous solution. The reaction is completed in 5 to 30 minutes, and the desired novel disazo compound of the present invention is obtained. The disazo compound of the present invention obtained as described above is particularly useful as a photoconductive material for electrophotographic photoreceptors. Thus, for example, (1) the disazo compound is mixed with a suitable resin binder such as polyester, polyamide, polyurethane, polyketone, polycarbonate, polystyrene, polyvinyltoluene, etc. in fine particles (about 0.05 mm in diameter).
(2) In addition to the above system (1), an inorganic photoconductive material (e.g., known cadmium sulfide, cadmium sulfide-selenium, etc.) is provided on a conductive support. or a photoreceptor to which an organic photoconductive material (e.g., known poly-N-vinylcarbazole, polyvinylpyrene, etc.) is added; Examples of applications of the new disazo compound include a laminated type photoreceptor formed by a photoreceptor method and a layer of another photoconductive substance formed thereon. The photoreceptor produced in this manner is no inferior to conventional photoreceptors and can fully achieve the object of the present invention. Next, the effects of the novel disazo compound of the present invention will be explained using an example of its use in a photoreceptor. 1 part by weight of polyester resin (Polyester Adhesive 49000, manufactured by Dupont), 1 part by weight of the disazo pigment of Compound No. 1 shown in Table 1, and 26 parts by weight of tetrahydrofuran were pulverized and mixed in a Pall mill, and the resulting dispersion was mixed. It was coated on a polyester film coated with aluminum using a doctor blade and dried at 100°C for 10 minutes to obtain a photoreceptor having a photosensitive layer with a thickness of 7 μm. Next, a +6KV corona discharge was applied to the photosensitive layer surface of this photoreceptor using a commercially available electrostatic copying paper tester for 20 seconds to positively charge it, and then it was left in a dark place for 20 seconds, and the surface potential at that time was Vpo (volts). Then, the photosensitive layer is irradiated with light from a tungsten lamp so that the surface has an illuminance of 20 lux, and the time (seconds) until the surface potential becomes 1/2 of Vpo is determined, and the exposure amount E1/ 2 (lux seconds). The results were Vo=175V and E1/2=49.5 Lux·sec. Examples are shown below. Example 1 (Production of tetrazonium salt) 18.0 g of 1,4-bis(2-aminostyryl)benzene was added to a dilute hydrochloric acid solution consisting of 600 ml of water and 40 ml of concentrated hydrochloric acid, stirred at 60°C for 30 minutes, and then heated to 0°C. cooled down to. Then, a solution prepared by dissolving 9.0 g of sodium nitrite in 25 ml of water was added dropwise to the solution over a period of 40 minutes at 0 to 4°C. After stirring at the same temperature for 30 minutes, 500 ml of water was added to the reaction mixture to remove trace amounts of insoluble matter. 42% borofluoric acid 30% in this solution
ml was added, and the precipitated crystals were separated, washed with water, and dried to obtain 27.2 g (yield 92.0%) of orange crystals of tetrazonium difluoroborate. The decomposition point is 83℃ or higher, and the infrared absorption spectrum (KBr tablet method) is as shown in Figure 1, with an absorption band based on N ₂ at 2230 cm ^-1 and an absorption band based on trans -CH=CH- at 960 cm ^-1. was recognized. Example 2 (Disazo compound: Compound No. 1) 30 g of the tetrazonium salt obtained in Example 1 and 3.3 g of 2-hydroxy-3-nafunae acid anilide as a coupling component were added to 390 ml of cooled N,N-dimethylformamide. After dissolving, a solution consisting of 1.9 ml of sodium acetate and 20 ml of water was added dropwise to the solution at a temperature below 5° C. over 1 hour. After stopping the cooling, the mixture was further stirred at room temperature for 3 hours. Thereafter, the formed precipitate is collected and washed three times with 300 ml of water, and then five times with 300 ml of N,N-dimethylformamide. Furthermore, residual N,N-dimethylformamide was washed away with acetone and dried at 70°C under a reduced pressure of 2 mmHg to obtain 4.7 g of the disazo compound of Compound No. 1 shown in Table 1.
(yield 91.0%). The infrared absorption spectrum of the obtained disazo compound is shown in FIG. Examples 3 to 14 (Disazo compounds: Production of compounds No. 2 to 13) Same as Example 1 except that the compounds in Table 2 below were used as coupling components in the production of the disazo compound of Compound No. 1 of Example 2. Disazo compounds of Compounds No. 2 to 13 shown in Table 1 were produced by the method.

【table】

【table】

【table】 [Brief explanation of the drawing]

FIG. 1 is an infrared absorption spectrum of the tetrazonium difluoroborate obtained in Example 1, and FIG. 2 is an infrared absorption spectrum of the novel disazo compound of the present invention obtained in Example 2.

Claims (1)

[Claims] 1. General formula [However, A is [Formula] or [Formula] (R is a lower alkyl group, a lower alkoxy group, a nitro group, a di-lower alkylamino group, or a halogen, n is an integer of 0, 1, 2, or 3, and n is an integer of 2 or 3, R may be the same or different groups. ] A novel disazo compound. 2 General formula [However, X represents an anionic functional group. ] and the general formula [Formula] or [Formula] [where R is a lower alkyl group, a lower alkoxy group, a nitro group, a di-lower alkylamino group, or a halogen, and n is 0, 1, 2 or 3 is an integer of
When n is an integer of 2 or 3, they may be the same or different groups. ] A general formula characterized by reacting with a compound represented by [However, A represents [Formula] or [Formula] (R is as described above). ] A method for producing a novel disazo compound.