JP2005053845A - Purification method of charge-transporting compound and electrophotographic photoreceptor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a purification method of a charge-transporting compound whereby the charge-transporting compound which is used for an electrophotographic photoreceptor, has at least one chain-polymerizable functional group and comprises a triphenylamine structure is obtained with a high purity. <P>SOLUTION: In the purification method, the charge-transporting compound which has a triphenylamine structure of formula (1) and has at least one chain-polymerizable functional group is dissolved in an organic solvent, the organic solvent containing the compound is contacted with at least one adsorbent chosen from the group consisting of a silica-alumina adsorbent such as activated clay and acid clay and a silica-magnesia adsorbent, the organic solvent containing the compound is separated from the adsorbent, and the organic solvent is removed from the organic solvent containing the compound to obtain a purified product of the charge-transporting compound. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for purifying a charge transporting compound, and an electrophotographic photoreceptor having a photosensitive layer formed using the charge transporting compound purified by using the purification method.

  Conventionally, inorganic electrophotographic photoreceptors using inorganic materials such as selenium, cadmium sulfide and zinc oxide have been mainly used as photoconductive materials used in electrophotographic photoreceptors. On the other hand, organic electrophotographic photoreceptors using organic materials have been actively researched and developed with the focus on advantages such as high productivity and non-pollution, and many photoconductive properties are similar to those of inorganic electrophotographic photoreceptors. In recent years, it has been found to be used as a mainstay in place of inorganic electrophotographic photoreceptors.

  These electrophotographic photoreceptors are often used as function-separated photoreceptors in which a charge generation layer and a charge transport layer are laminated in order to satisfy both electrical and mechanical properties.

  At this time, the structure and purity of the charge transporting compound are important in order to express stable and highly sensitive electrical characteristics even when used for a long time as well as in the initial stage. Therefore, charge purification compounds usually require high-purity materials, and various purification methods are being studied. Usually, the crude product is subjected to recrystallization, column separation / purification using silica or alumina column, activated carbon treatment, etc., and if necessary, the treatment is repeated several times or combined for treatment. Yes. In addition, a method of treating a charge transporting compound with activated clay is known (see, for example, Patent Documents 1 to 5).

  On the other hand, an electrophotographic photoreceptor is required to have sensitivity, electrical characteristics, and optical characteristics according to the electrophotographic process applied to the electrophotographic photoreceptor. In particular, in the case of a photoreceptor that is used repeatedly, the surface of the photoreceptor is subjected to electrical and mechanical external forces such as charging, image exposure, toner development, transfer to paper, and a cleaning process, so that the durability against them is increased. Sex is required. Specifically, durability against surface wear and scratches caused by rubbing, surface deterioration due to charging (for example, transfer efficiency and slipperiness drop), durability against deterioration of electrical characteristics such as sensitivity reduction and potential drop. Is also required.

  In general, the surface of the photoreceptor is a thin resin layer, and the characteristics of the resin are very important. In recent years, acrylic resins and polycarbonate resins have been put to practical use as resins that satisfy the above-mentioned conditions to some extent. However, not all of the above-mentioned characteristics are satisfied with these resins, and in particular, the high performance of the photoconductor. It cannot be said that the coating film hardness of the resin is sufficiently high for achieving durability. When these resins are used as the resin for forming the surface layer, the surface layer is worn and repeatedly damaged when used repeatedly.

  Furthermore, due to the recent demand for higher sensitivity of organic electrophotographic photoreceptors, relatively large amounts of low molecular weight compounds such as charge transporting compounds have been added. However, in this case, since the strength of the film is remarkably reduced by the action of the plasticizer of these low molecular weight substances, the surface layer wear and scratches become even more problematic when used repeatedly. In addition, when the electrophotographic photosensitive member is stored for a long period of time, the low molecular weight component is precipitated, resulting in layer separation.

In order to solve such a problem, a photoreceptor using a curable resin as a resin for a charge transport layer is known (for example, see Patent Document 6). Thus, when the charge transport layer is formed by curing and cross-linking using a curable resin, the mechanical strength of the photoreceptor increases, and the abrasion resistance and scratch resistance when used repeatedly are improved. However, even when a curable resin is used, since the low molecular weight component acts as a plasticizer in the binder resin, the problem of precipitation and layer separation as described above cannot be fundamentally solved. In addition, in a charge transport layer composed of an organic charge transporting compound and a binder resin, the charge transport ability varies greatly depending on the resin composition. For example, a curable resin having a high hardness can sufficiently satisfy the charge transport ability. However, there are problems such as an increase in residual potential when used repeatedly. Neither charge transport ability nor hardness has been satisfied.

  In addition, the charge transport layer contains a monomer having a carbon-carbon double bond, and reacts with the carbon-carbon double bond of the charge transport compound by heat or light energy to form a charge transport layer cured film. Photosensitive members are also known (see, for example, Patent Documents 7 and 8). However, the charge transporting compound described here only has a monomer immobilized on the polymer main skeleton in a pendant form, and does not sufficiently eliminate the plastic action described above, and has sufficient mechanical strength. is not. Further, if the concentration of the charge transporting compound is increased in order to improve the charge transporting ability, the crosslinking density is lowered and sufficient mechanical strength cannot be ensured. Furthermore, there is a concern about the adverse effect on the electrophotographic characteristics due to the addition of initiators required at the time of polymerization.

  As another solution, there is known an electrophotographic photosensitive member in which a charge transporting layer is formed by introducing a group having a charge transporting ability into a thermoplastic polymer main chain (see, for example, Patent Document 9). However, the charge transport layer described here is a thermoplastic resin, although it has an effect on precipitation and layer separation compared with the conventional molecular dispersion type charge transport layer, and the mechanical strength is improved. Therefore, its mechanical strength is limited, and it is difficult to say that it is sufficient in terms of handling and productivity including resin solubility.

  Under such circumstances, the present inventors have used a specific charge transporting compound having a chain polymerizable functional group as a photoconductor that satisfies both high mechanical strength and high charge transporting ability, Alternatively, a photoreceptor having a photosensitive layer formed by crosslinking / curing by heat has been provided (see, for example, Patent Documents 10 to 15). In particular, a photoreceptor using a film obtained by crosslinking / curing such a charge transporting compound as the surface layer located on the outermost surface of the photosensitive layer shows particularly good results.

  However, a film obtained by curing a charge transporting compound having a chain polymerizable functional group as described herein is higher than the ionization potential (oxidation potential) of the original charge transporting compound having a chain polymerizable functional group. Become. Especially when the charge transporting compound is a charge transporting compound having two or more chain-polymerizable functional groups having a triphenylamine structure, the phenyl group substituted with the chain-polymerizable functional group by curing is twisted, in particular ionization potential. Tend to be higher. Therefore, if such a film contains a compound having a low ionization potential as an impurity, the electrical characteristics of the film are adversely affected. Since the electrical characteristics of the photoreceptor (for example, increase in residual potential and potential fluctuation during durability) are affected by the purity of the charge transporting compound used, well-purified charge transport in such a photoreceptor. It is important to use sex compounds.

  Furthermore, charge transporting compounds having a chain-polymerizable functional group as described herein are generally liquid compounds at room temperature because of their structure, so that charge transport such as the purification method by recrystallization as described above is generally used. In many cases, a purification method that has been used as a purification method for a chemical compound cannot be applied. Even if a column purification method using an adsorbent such as silica gel or alumina is applied, it is extremely difficult to optimize column purification conditions and there is a problem with reproducibility, and it is satisfactory to always obtain a purified product of a certain quality. It is not a way to go. In particular, a charge transporting compound having a chain polymerizable functional group is not preferable from the viewpoint of always providing mass-produced products and a purified product having a certain quality because it polymerizes when contacted for a long time with silica gel or alumina. .

Therefore, in order to form a favorable photosensitive layer in an electrophotographic photoreceptor, it has been desired to provide a charge transporting compound having a highly pure chain-polymerizable functional group used in the photosensitive layer.
JP 60-233156 A Japanese Patent Laid-Open No. 4-310962 JP-A-7-56365 JP-A-7-261423 JP 2002-14478 A Japanese Patent Laid-Open No. 02-127652 JP 05-216249 A Japanese Patent Laid-Open No. 07-72640 Japanese Patent Laid-Open No. 08-248649 Japanese Patent Laid-Open No. 11-265085 Japanese Unexamined Patent Publication No. 2000-066424 Japanese Patent Laid-Open No. 2000-066425 Japanese Unexamined Patent Publication No. 2000-206715 Japanese Unexamined Patent Publication No. 2000-206716 JP 2001-166519 A

  The present invention has been made under such circumstances. A charge transporting compound having at least one chain-polymerizable functional group used in an electrophotographic photosensitive member and having a triphenylamine structure has high purity. It is an object of the present invention to provide a method for purifying a charge transporting compound that can be obtained. More specifically, impurities that adversely affect the photoreceptor characteristics can be removed well, a highly purified charge transport compound can always be obtained stably, and the charge transport compound has excellent mass productivity It is an object of the present invention to provide a purification method.

  Another object of the present invention is to provide an electrophotographic photoreceptor having a photosensitive layer formed using a charge transporting compound purified by such a purification method.

  Therefore, as a result of intensive studies, the present inventors have found that the above problem can be solved by adopting the following configuration.

That is, the present invention is as follows.
[1] A charge transporting compound having a triphenylamine structure represented by the following general formula (1) and having at least one chain polymerizable functional group is dissolved in an organic solvent, and the charge transporting compound-containing organic The solvent is contacted with at least one adsorbent selected from silica / alumina adsorbents of active clay and acidic clay and silica / magnesia adsorbent, and then the adsorbent and the organic solvent containing the charge transporting compound And then removing the organic solvent from the charge-transporting compound organic solvent to obtain a purified product of the charge-transporting compound.

(In the formula (1), Ar ¹ , Ar ² and Ar ³ represent phenyl groups, and each phenyl group has a substituent at the para position with respect to the nitrogen atom.)
[2] The method for purifying a charge transporting compound according to [1], wherein the chain polymerizable functional group is any one of the following general formulas (2) to (6).

[3] The method for purifying a charge transporting compound according to [1] or [2], wherein the charge transporting compound represented by the general formula (1) is liquid at 20 ° C. or higher.
[4] The method for purifying a charge transporting compound according to any one of [1] to [3], wherein the method is further contacted with silica gel or alumina after contacting with activated clay.
[5] The method for purifying a charge transporting compound according to any one of [1] to [4], wherein the charge transporting compound represented by the general formula (1) has at least two chain polymerizable functional groups.
[6] The charge transporting compound according to any one of [1] to [5], wherein the charge transporting compound represented by the general formula (1) is represented by the following general formula (7): Purification method.

(In formula (7), R ₁ , R ₂ and R ₃ each represents an alkyl group, an aralkyl group or an aryl group which may have a substituent, and may be the same or different. Each independently represents an integer of 0 to 3. P ₁ , P ₂ and P ₃ each represent a chain polymerizable functional group, a, b and c each independently represent an integer of 0 to 4, n, m and l represents an integer of 0 to 2, and n + m + 1 represents an integer of at least 1 and the products of n and y, m and x, and l and z are not 0. In addition, any phenyl group of triphenylamine is (It has a substituent in the para position to the nitrogen atom.)
[7] The method for purifying a charge transporting compound according to any one of [1] to [6], wherein an oxidation potential of the charge transporting compound represented by the general formula (1) is 0.75 (v) or more. .
[8] In an electrophotographic photosensitive member having a photosensitive layer provided on a conductive support,
The photosensitive layer forms the surface of the electrophotographic photosensitive member and is composed of a single layer or a plurality of stacked layers,
The photosensitive layer composed of a single layer or the layer forming the surface of the electrophotographic photoreceptor among the photosensitive layers composed of a plurality of layers is any one of [1] to [7] An electrophotographic photoreceptor comprising a charge transporting compound purified by a purification method.

  According to the present invention, a highly pure charge transporting compound can always be obtained stably and simply, and a method for purifying a charge transporting compound excellent in mass productivity can be provided.

  In addition, by forming an electrophotographic photoreceptor using the charge transporting compound purified using the purification method of the present invention, an electrophotographic photoreceptor excellent in electrical characteristics and durability can be provided.

Hereinafter, the present invention will be described in detail.
<About purification method of charge transporting compound>
The purification method of the present invention is directed to a charge transporting compound having a triphenylamine structure represented by the following general formula (1) and having at least one chain polymerizable functional group.

(In the formula (1), Ar ¹ , Ar ² and Ar ³ represent phenyl groups, and each phenyl group has a substituent at the para position with respect to the nitrogen atom.)
In the present invention, chain polymerization refers to the former polymerization reaction form when the polymer formation reaction is largely divided into chain polymerization and sequential polymerization. For details, see, for example, “Basic Chemistry Resin Chemistry” by Tadahiro Miwa. (New Edition) ”July 25, 1995 (1 edition, 8 prints) As described in 24, the form mainly refers to unsaturated polymerization, ring-opening polymerization, and isomerization polymerization in which the reaction proceeds via an intermediate such as a radical or ion. In the present invention, the chain polymerizable functional group means a functional group capable of the above-described reaction form. Of these, unsaturated polymerization is particularly preferred.

  Here, the unsaturated polymerization refers to a reaction in which an unsaturated group such as C═C, C≡C, C═O, C═N, C≡N, or the like is polymerized by radicals, ions, or the like. Most of the cases are due to C = C.

  Preferable examples of the chain polymerizable functional group (especially unsaturated polymerizable functional group) of the present invention include a group represented by the following general formula (8).

In the above formula (8), E has a hydrogen atom, a halogen atom such as fluorine, chlorine and bromine, an optionally substituted alkyl group such as a methyl group, an ethyl group, a propyl group and a butyl group, and a substituent. Aralkyl groups such as benzyl group, phenethyl group, naphthylmethyl group, furfuryl group and thienyl group, phenyl group, naphthyl group, anthryl group, pyrenyl group, thiophenyl group and furyl group which may have a substituent An alkoxy group such as an aryl group, a methoxy group, an ethoxy group, and a propoxy group, a CN group, a nitro group, —COOR ⁴ or CONR ⁵ R ⁶ . W is an arylene group such as divalent phenylene, naphthylene and anthracenylene which may have a substituent, a divalent alkylene group such as methylene, ethylene and butylene which may have a substituent, -COO-, -CH _{2 -, - O -, -} OO -, - S- or -CONR ⁷ - shows a.

R ⁴ , R ⁵ , R ⁶ and R ⁷ are hydrogen atoms, halogen atoms such as fluorine, chlorine, bromine and iodine, and alkyl groups such as methyl, ethyl, propyl and butyl groups which may have a substituent. An aralkyl group such as a benzyl group and a phenethyl group which may have a substituent, or an aryl group such as a phenyl group, a naphthyl group and an anthryl group which may have a substituent, and R ⁵ and R ⁶ are They may be the same or different.

  F represents 0 or 1.

  In the above E and W, the substituents which may be included are halogen atoms such as fluorine, chlorine, bromine and iodine, alkyl such as nitro group, cyano group, hydroxyl group, methyl group, ethyl group, propyl group and butyl group. Group, alkoxy group such as methoxy group, ethoxy group and propoxy group, aryloxy group such as phenoxy group and naphthoxy group, aralkyl group such as benzyl group, phenethyl group, naphthylmethyl group, furfuryl group and thienyl group or phenyl group, naphthyl group And aryl groups such as a group, anthryl group, and pyrenyl group.

  Specific examples of the unsaturated polymerizable functional group represented by the general formula (8) are shown in Table 1 below. However, it is not limited to these.

  In Table 1, R is an alkyl group such as a methyl group, an ethyl group, a propyl group and a butyl group which may have a substituent, a benzyl group, a phenethyl group or a naphthylmethyl group which may have a substituent. , An aralkyl group such as a furfuryl group and a thienyl group, an aryl group such as a phenyl group, a naphthyl group and an anthryl group which may have a substituent, or a hydrogen atom.

  Moreover, in this invention, what is shown by following General formula (2)-(6) is mentioned as a chain polymerizable functional group which is a more preferable unsaturated polymerizable functional group. Furthermore, in consideration of the case where it is finally cured and used as the surface layer of the photoreceptor, particularly preferred chain polymerizable functional groups are acryloyloxy groups of general formula (2) and methacryloyloxy groups of general formula (3). It is.

  In addition, the chain polymerizable functional group in the general formula (1) is more preferably 2 or more.

In the above general formula (1), the phenyl group represented by Ar ¹ , Ar ² and Ar ³ may have a halogen atom such as fluorine, chlorine, bromine or iodine, a hydroxyl group, a methyl group, or ethyl. Group, alkyl group such as propyl group and butyl group, alkoxy group such as methoxy group, ethoxy group and propoxy group, aryloxy group such as phenoxy group and naphthoxy group, benzyl group, phenethyl group, naphthylmethyl group, furfuryl group, thienyl And an aralkyl group such as a group or an aryl group such as a phenyl group, a naphthyl group, an anthryl group and a pyrenyl group.

  The charge transporting compound represented by the general formula (1) is a liquid at 20 ° C. or higher, but the charge transporting compound in such a state is preferably applied to the purification method of the present invention. be able to.

  Among the above general formula (1), the charge transporting compound represented by the following general formula (7) is particularly preferable from the viewpoints of electrical characteristics such as charge transport characteristics and polymerization rate.

In the above formula (7), R ₁ , R ₂ and R ₃ are each optionally substituted alkyl groups such as methyl, ethyl, propyl and butyl groups, methoxy groups, ethoxy groups and propoxy groups. Or an aryl group such as a phenyl group or a naphthyl group, which may be the same or different. x, y, and z each independently represent an integer of 0 to 3. P ₁ , P ₂ and P ₃ each represent a chain polymerizable functional group. In particular, the chain polymerizable functional group represented by the general formulas (2) to (6) is preferable. a, b and c each independently represent an integer of 0 to 4; n, m and l represent integers of 0 to 2, n + m + 1 represents an integer of at least 1 and the products of n and y, m and x, and l and z are not 0, respectively. In addition, any phenyl group of triphenylamine has a substituent at the para position with respect to the nitrogen atom.

  The oxidation potential of the charge transporting compound represented by the general formula (1) is preferably 0.75 (v) or more. That is, a photoconductor using a film obtained by curing a charge transporting compound having such a chain polymerizable functional group as the outermost surface layer is extremely difficult to scrape. Therefore, when used for a long period of time, the outermost surface layer is extremely susceptible to oxidative deterioration due to discharge or the like, and a film in which a normal low molecular charge transporting compound is dispersed is required to have further oxidative deterioration property. If the outermost surface layer is oxidized, the oxidation potential may be at least 0.75 (v) or more at the monomer stage because it causes image defects such as image flow and deterioration of electrical characteristics such as potential fluctuations during durability. preferable.

  Of particular importance in the present invention, in the charge transporting compound represented by the general formula (1), any phenyl group of triphenylamine has a substituent in the para position with respect to the nitrogen atom, in other words, at the nitrogen atom. On the other hand, the para position of the phenyl group is not a hydrogen atom. This point will be described in detail below.

  The activated clay or acidic clay silica / alumina adsorbent or silica / magnesia adsorbent used for purification in the present invention is generally an acidic substance and adsorbs impurities derived from aromatic amine electron donating compounds. It is easy to do and it is suitable to process in a short time. Therefore, since the purification effect is high in a short time treatment, it is an effective purification method with a very low risk of polymerizing a charge transporting compound having a chain polymerizable functional group as in the present invention during purification. However, when the phenyl group para-position is a hydrogen atom with respect to the nitrogen atom, some oxidative coupling between para-positions occurs between molecules if the adsorbent is contacted for a short time. The compound oxidatively coupled at the para positions becomes a benzidine compound, but the structure has a much lower ionization potential (oxidation potential) than that of the original triphenylamine compound, and the hole serving as a carrier in the charge transport layer. Traps the residual potential, significantly increasing the residual potential, changing the potential during durability, or significantly affecting the memory characteristics. Further, as described above, the film obtained by curing the charge transporting compound having a chain polymerizable functional group has a higher ionization potential than the charge transporting compound itself having the original chain polymerizable functional group. In particular, a charge transporting compound having two or more chain polymerizable functional groups in a triphenylamine compound has a phenyl group twisted by taking a three-dimensional structure by curing, and this tendency is particularly remarkable. Therefore, even a very small amount of a contaminant-cured film such as a low ionization potential compound has a significant adverse effect on the electrical characteristics. On the other hand, when the charge transporting compound defined in the present invention having a substituent in the para position of the phenyl group with respect to the nitrogen atom is used, the coupling at the ortho position and the meta position is a steric reason and an electron density reason. The reaction is extremely difficult to occur due to either or both of the above, and even if it occurs, the benzidine compound produced is very small compared to the compound coupled at the previous para position, and the decrease in oxidation potential (ionization potential) is structurally There is almost no adverse effect on the electrical properties (although in some cases the phenyl group may be higher due to the significant twisting of the original compound). Therefore, using a specific charge transporting compound in which all the para-positions in the phenyl group are blocked with respect to the nitrogen atom, and contacting with the specific adsorbent described above, it is extremely efficient and has a certain quality that minimizes the risk of polymerization. The purified compound can be simply and stably provided.

  Specific examples of the charge transporting compound having a triphenylamine structure represented by the general formula (1) having at least one chain polymerizable functional group used in the present invention are shown in Tables 2-1 and 2- below. It is shown in 2. However, it is not limited to these.

  Next, the purification method of the present invention will be described in more detail.

  The charge transporting compound represented by the general formula (1) is dissolved in an organic solvent, and the organic solvent containing the charge transporting compound is made of silica / alumina adsorbent such as activated clay or acid clay and silica / magnesia adsorbent. By contacting with at least one adsorbent selected from among the following, separating the adsorbent and the organic solvent containing the charge transporting compound, and then removing the organic solvent from the organic solvent containing the charge transporting compound Then, a purified product of the charge transporting compound from which impurities are removed is obtained.

  As the method of contacting, the charge transporting compound is dissolved in an organic solvent, the adsorbent in powder form is added, and after stirring, the adsorbent is filtered by filtration, and then the solvent of the filtrate is concentrated. Examples thereof include a method of concentrating the eluate through a place where a transporting compound is dissolved in a solvent and the powdery adsorbent is packed in a column or the like.

The organic solvent for dissolving the charge transporting compound defined in the present invention and the organic solvent used for development in a column or the like can be used without particular limitation as long as the charge transporting compound can be dissolved. For example, any of hydrocarbons, esters, ethers, halides, alcohols, acid amides, aldehydes, nitriles, ketones, aromatic nitro compounds, alkyl sulfoxides and the like may be used. Among them, particularly preferred are aromatic hydrocarbons such as toluene, xylene, and cymene, halogen compounds such as chloroform, dichloroethane, trichloroethane, and chlorobenzene, alcohols such as methanol, ethanol, propanol, and butanol, and ketones such as acetone and methyl ethyl ketone. Examples thereof include aliphatic hydrocarbons such as compounds, hexane, heptane and octane, ethers such as tetrahydrofuran and dioxane, and esters such as ethyl acetate and butyl acetate, which may be used alone or in combination.

  The active clay or acidic clay or silica / magnesia type adsorbent, which is a silica / alumina type adsorbent that can be used in the present invention, will be described below.

  Acid clay is a substance in which montmorillonite is a main component and a small amount of cristobalite is mixed, and the main component is silica / alumina. Powdered or granular commercial products can be used, for example, Mizusawa Chemical Industry Co., Ltd. (trade name: Mizuka Ace), Kishida Chemical Co., Ltd. acid clay, etc., and other products that are generally manufactured and sold can also be used.

  As the activated clay, natural minerals such as kaolin, bentonite, perlite, bauxite, and acid clay, and activated clay obtained by activating acid clay with sulfuric acid treatment can be used. Preferred examples include activated activated clay, such as Nihon Activated Soil Co., Ltd. (trade name: Activated Soil), Mizusawa Chemical Industry Co., Ltd. (trade names: Galeon Earth, Galeonite), and others. You can also use it.

  Examples of the silica / magnesia-based adsorbent include porous adsorbents mainly composed of silicon dioxide and magnesium oxide, Mizusawa Chemical Industry Co., Ltd. (trade name: Mizuka Life), and others. You can also use it. Among the adsorbents, activated clay and silica / magnesia adsorbent are particularly preferable.

  The adsorbent is effective in an amount of 5% by mass or more, preferably 10 to 500% by mass, particularly preferably 10 to 200% by mass, based on the charge transporting compound to be treated. The treatment temperature should just be more than the temperature which the solvent to use does not solidify, Preferably it is 5-200 degreeC, Most preferably, it is 20-120 degreeC. Although contact time can be selected arbitrarily, 5 minutes or more are preferable and a sufficient effect is expressed in about 5 to 120 minutes.

  The adsorbent contact treatment may be performed by any one type, but in some cases, several types may be processed in parallel or mixed and processed.

  Further, the effect may be further enhanced by performing a combination of recrystallization treatment, activated carbon treatment, alumina treatment, or silica treatment before and after the adsorbent contact treatment. In particular, in the present invention, the contact treatment of activated clay and the contact treatment of silica gel or alumina may be performed in combination. In particular, after contacting with activated clay, it may be further contacted with silica gel or alumina.

Further, in the present invention, purification was carried out with hydrochloric acid aqueous solution, silica gel, or acidic alumina listed as the acidic substance in the prior art, but active clay or acidic clay, which is a silica / alumina adsorbent, or silica / magnesia adsorbent, etc. It was not possible to see such a specific characteristic improvement effect. Therefore, it can be said that the effect of the present invention is not due to the purification effect as an acidic substance, but due to the inherent effect of the active clay or acidic clay, which is a silica / alumina adsorbent, or a silica / magnesia adsorbent.
<About electrophotographic photoreceptor>
The electrophotographic photoreceptor of the present invention comprises a conductive support and a structure having a photosensitive layer on the conductive support, and is formed using the charge transporting compound obtained by the purification method described above. Having a layer. In the present invention, the layer formed using the charge transporting compound is more preferably a surface layer located on the outermost surface of the photosensitive layer. For the electrophotographic photosensitive member having a surface layer, for example, refer to the electrophotographic photosensitive member described in JP-A-11-265085, JP-A-2000-066424, JP-A-2000-066425, or the like. Can do.

  The preferred embodiments of the electrophotographic photoreceptor of the present invention are described below.

  The photosensitive layer forms the surface of the electrophotographic photoreceptor and is composed of a single layer or a plurality of stacked layers. More specifically, the charge generation material and the charge transport material are composed of a single layer containing the charge generation material and the charge transport material (hereinafter also referred to as a single layer type), or the charge generation layer containing the charge generation material and the charge transport A charge transport layer containing a functional compound is laminated (hereinafter also referred to as a laminated type), or a protective layer is further formed on these layers. In the present invention, a photoreceptor composed of a laminated photosensitive layer is more preferable.

  Next, in the electrophotographic photosensitive member of the present invention, the layer forming the surface of the electrophotographic photosensitive member among the photosensitive layer composed of a single layer or the photosensitive layer composed of a plurality of layers ( Hereinafter, these layers are collectively referred to as a surface layer) by using the charge transporting compound purified by the above purification method. More specifically, the surface layer is formed by polymerizing and crosslinking the purified charge transporting compound to form a cured film. The surface layer referred to in the present invention corresponds more specifically when the photosensitive layer is the above single layer, and when the protective layer is further formed on the layer. This protective layer corresponds. Further, when the photosensitive layer is of the above-described laminated type, a charge transport layer corresponds, and when a protective layer is further formed on the charge transport layer, the protective layer corresponds.

  The electrophotographic photoreceptor of the present invention having the surface layer obtained as described above is an electrophotographic photoreceptor excellent in electrical characteristics and durability.

Hereinafter, the present invention will be described with reference to examples.
(Example 1)
By the following step (A), the compound Nos. Twelve charge transporting compounds were synthesized and purified.

  In step (A), the compound of A-1 (50 g, 0.41 mol), the compound of A-2 (376 g, 1.24 mol), anhydrous potassium carbonate (180 g) and copper powder (400 g) The mixture was stirred with chlorobenzene (1.0 kg) at 180 to 190 ° C. for 24 hours. After filtering the reaction solution, the solvent was removed under reduced pressure. Excess A-2 compound in the residue was removed by distillation under reduced pressure, and then added to 1.5 kg of ethanol, and caustic soda (100 g) was slowly added with stirring at room temperature. After completion of the addition, the mixture was stirred as it was at room temperature for 1 hour, and further heated and stirred at 70 to 80 ° C. for 10 hours. The reaction solution was poured into water, neutralized with dilute hydrochloric acid, extracted with ethyl acetate, the organic layer was dried over anhydrous sodium sulfate, and the solvent was removed under reduced pressure. The residue was recrystallized using a toluene / methyl ethyl ketone mixed solvent to obtain 85 g of a compound of A-4.

  A-4 compound (82 g, 0.21 mol), acrylic acid (38 g, 0.53 mol) and P-methoxyphenol (260 mg) were dissolved in toluene (400 g), and then P-toluenesulfonic acid (monohydrate) ( 2.0 g) was added at room temperature. Thereafter, the mixture was heated in an oil bath and dehydrated and refluxed for 7 hours. The reaction solution was poured into ice water, neutralized with 10% caustic soda and extracted with ethyl acetate. The organic layer was washed with water and dried over anhydrous magnesium sulfate. Thereafter, the solvent was distilled off under reduced pressure to obtain 98.5 g of a crude product A-5 compound.

The compound (5 g) of the crude product A-5 was dissolved in 10 ml of toluene, 5 g of activated clay (manufactured by Kishida Chemical Co., Ltd.) was added thereto, and the mixture was stirred for 30 minutes at room temperature. The activated clay was filtered using a 1 μm filter paper and further filtered using a 0.5 μm membrane filter. The filtrate was removed under reduced pressure to obtain 4.8 g of purified product A-5 compound (viscous liquid).

  Next, using the compound of the obtained purified product A-5, a photoreceptor was prepared as follows, and the photoreceptor was evaluated.

  Polyamide resin (6-60-64-124 base nylon copolymer) 1 part (parts by mass; the same applies hereinafter) and 8-nylon resin (methoxymethylated nylon, methoxylation rate of about 30%) 3 parts 50 parts of methanol It melt | dissolved in 40 parts of butanol, and prepared the coating material for intermediate | middle layers. This paint was applied on an aluminum sheet with a Meyer bar and dried at 100 ° C. for 20 minutes to form a 0.65 μm intermediate layer.

  Three parts of a hydroxygallium phthalocyanine crystal having strong peaks at 7.4 ° and 28.2 ° at a black angle of 2θ ± 0.2 ° in X-ray diffraction of CuKα, polyvinyl butyral (trade name S-REC BM2, Sekisui Chemical) 1.0 part and 35 parts of cyclohexanone (manufactured by Co., Ltd.) were dispersed in a sand mill using a φ1 mm glass bead for 24 hours, and then 60 parts of ethyl acetate was added to prepare a charge generation layer coating material. This paint was applied onto the above intermediate layer with a Meyer bar and dried at 105 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.12 μm.

  Next, 4.0 parts of the purified product A-5 compound obtained in Example 1 as a charge transporting compound and 5.5 parts of bisphenol Z-type polycarbonate (viscosity average molecular weight 45,000) were added to 38 parts of monochlorobenzene. It melt | dissolved and the coating material for charge transport layers was prepared. This paint was applied onto the charge generation layer by a dip coating method and dried at 110 ° C. for 60 minutes to form a charge transport layer having a film thickness of 18 μm to produce an electrophotographic photosensitive member.

This photoreceptor is attached to a cylinder of a laser beam printer (Laser Jet 4000: manufactured by Hewlett Packard), and the initial dark potential (Vd) is normal temperature and humidity (23 ° C., 55% RH) (N / N). The amount of light (EΔ500) required to set the charge to −700 (V) and irradiate it with laser light having a wavelength of 780 (nm) to lower the potential of −700 (V) to −200 (V). ) Was measured as sensitivity. Further, the initial characteristics were measured by setting the potential when the light amount of 20 (μJ / cm ² ) was irradiated as the residual potential (Vr). The other conditions were as follows: transfer current: +5.5 μA, process speed: 96 mm / sec.

  Further, after resetting these photoconductors to have a dark part potential of −700 (V) and a light part potential of −200 (V), they were subjected to low temperature and low humidity (10 ° C., 10% RH) (L / L). The durability of passing 1000 sheets continuously was measured, and the fluctuation amounts ΔVd and ΔVl of the absolute values of the dark part potential and the bright part potential after the initial and 1000 sheets were measured. The results are shown in Table 3 below.

  Further, after forming the intermediate layer and the charge generation layer on the aluminum sheet in the same manner as above, the compound (60 parts) of the purified product A-5 obtained above was mixed in a mixed solvent of 30 parts of monochlorobenzene and 30 parts of dichloromethane. Dissolved and prepared a charge transport layer coating material. This coating material was applied onto the charge generation layer with a Meyer bar and dried at 50 ° C. for 10 minutes, and then irradiated with an electron beam under the conditions of an acceleration voltage of 150 KV and an irradiation dose of 5 Mrad. A curable charge transport layer having a thickness of 12 μm was formed to obtain an electrophotographic photosensitive member. The initial characteristics (EΔ500 and Vr) of this photoreceptor were evaluated in the same manner as described above. The results are shown in Table 3.

(Example 2)
The compound of purified product A-5 was treated in the same manner as in Example 1 except that the activated clay in Example 1 was replaced with acid clay (trade name; Mizuka Ace # 300, manufactured by Mizusawa Chemical Co., Ltd.). 6 g was obtained. Next, the obtained purified product A-5 was used as a photoreceptor in the same manner as in Example 1 for evaluation. The results are shown in Table 3.
(Example 3)
The activated clay of Example 1 was treated in the same manner as in Example 1 except that the silica / magnesia-based adsorbent (manufactured by Mizusawa Chemical Co., Ltd .: trade name; Mizuka Life P-1) was used. 4.5 g of compound 5 was obtained. Next, the obtained purified product A-5 was used as a photoreceptor in the same manner as in Example 1 for evaluation. The results are shown in Table 3.
Example 4
40 g of silica gel (Fuji Silysia Chemical Co., Ltd .: trade name BW-200) is packed in a column (20 mmΦ), and the purified product A-5 compound (4.0 g) obtained in Example 1 is dissolved in 20 ml of toluene. Then, purification was performed using toluene as a developing solvent to obtain a further purified product A-5 compound (3.2 g). Next, the resulting further purified product A-5 was used as a photoreceptor in the same manner as in Example 1 for evaluation. The results are shown in Table 3.
(Example 5)
40 g of silica gel (manufactured by Fuji Silysia Chemical Co., Ltd .: trade name BW-200) was packed in a column (20 mmΦ), and the compound (4.0 g) of crude product A-5 obtained in Example 1 was dissolved in 20 ml of toluene. Then, purification was performed using toluene as a developing solvent. After partially concentrating the developing solution, 2.0 g of activated clay (manufactured by Kishida Chemical Co., Ltd.) was added thereto and stirred at room temperature for 30 minutes. The activated clay was filtered using 1 μm filter paper, and further filtered using a 0.5 μm membrane filter. The filtrate was removed under reduced pressure to obtain 2.8 g of the purified product A-5 compound. Next, the obtained purified product A-5 was used as a photoreceptor in the same manner as in Example 1 for evaluation. The results are shown in Table 3.
(Example 6)
The same treatment as in Example 3 was carried out except that the solvent used in Example 3 was changed from toluene to ethanol to obtain 4.2 g of the compound of purified product A-5. Next, the obtained purified product A-5 was used as a photoreceptor in the same manner as in Example 1 for evaluation. The results are shown in Table 3.
(Example 7)
The same treatment as in Example 1 was carried out except that the solvent used in Example 1 was changed from toluene to ethyl acetate to obtain 4.6 g of the purified product A-5 compound. Next, the obtained purified product A-5 was used as a photoreceptor in the same manner as in Example 1 for evaluation. The results are shown in Table 3.
(Example 8)
The same treatment as in Example 1 was carried out except that the treatment time in Example 1 was changed from 30 minutes to 2 hours to obtain 4.7 g of the purified product A-5 compound. Next, the obtained purified product A-5 was used as a photoreceptor in the same manner as in Example 1 for evaluation. The results are shown in Table 3.
Example 9
Except having changed the processing temperature of Example 1 into 80 degreeC, the process similar to Example 1 was performed and 4.7g of compounds of refined product A-5 were obtained. Next, the obtained purified product A-5 was used as a photoreceptor in the same manner as in Example 1 for evaluation. The results are shown in Table 3.
(Example 10)
20 g of activated clay (manufactured by Kishida Chemical Co., Ltd.) is packed in a column (20 mmΦ), the compound (4.0 g) of crude product A-5 obtained in Example 1 is dissolved in 20 ml of toluene, and toluene is used as a developing solvent. And purified. The developing solution was removed under reduced pressure to obtain 2.8 g of the purified product A-5 compound. Next, the obtained purified product A-5 was used as a photoreceptor in the same manner as in Example 1 for evaluation. The results are shown in Table 3.
(Example 11)
By the following step (B), the compound Nos. 36 charge transporting compounds were synthesized and purified.

In the step (B), the compound of B-1 (500 g, 1.7 mol), the compound of B-2 (80 g, 0.86 mol), anhydrous potassium carbonate (478 g) and copper powder (550 g) The mixture was stirred with 2 kg of chlorobenzene at 180 to 190 ° C. for 18 hours. After filtering the reaction solution, the solvent was removed under reduced pressure, and the residue was recrystallized twice with an acetone / methanol mixed solvent to obtain 510 g of the compound of B-3.
After cooling 35 g of DMF to 0-5 ° C., phosphorus oxychloride (184 g, 1.2 mol) was slowly added dropwise so as not to exceed 10 ° C. After completion of dropping, the mixture was stirred for 15 minutes as it was, and then a B-3 compound (500 g, 1.2 mol) / DMF 500 g solution was slowly added dropwise. After completion of dropping, the mixture was stirred for 30 minutes and then returned to room temperature. After stirring for 1 hour, the mixture was further heated to 80 to 85 ° C. and stirred for 4 hours. The reaction solution was poured into 5 kg of about 15% aqueous sodium acetate solution and stirred for 12 hours. After neutralizing it, extraction was performed using toluene, the organic layer was dried over anhydrous sodium sulfate, the solvent was removed, and the residue was purified with a silica gel column to obtain 378 g of the compound of B-4.

  The compound of B-4 (300 g, 0.67 mol) and 1,1-diphenylmethyldiethyl phosphate (205 g, 0.67 mmol) were dissolved in 2 kg of dry tetrahydrofuran, where oily sodium hydride (about 60%, 29.7 g, about 0.74 mol) was added slowly. After completion of the addition, the mixture was stirred at room temperature for 30 minutes and then heated and stirred for 3 hours. The reaction solution was cooled, poured into water, extracted with toluene, the organic layer was dried over anhydrous sodium sulfate, and the solvent was removed. The residue was purified with a silica gel column to obtain 211 g of the compound of B-5.

  The compound of B-5 (200 g, 0.34 mol) was added to 2 kg of methyl cellosolve, and sodium methylate (70 g) was slowly added while stirring at room temperature. After completion of the addition, the mixture was stirred at room temperature for 1 hour and further heated and stirred at 70 to 80 ° C. for 12 hours. The reaction solution was poured into water, neutralized with dilute hydrochloric acid, extracted with ethyl acetate, the organic layer was dried over anhydrous sodium sulfate, and the solvent was removed under reduced pressure. The residue was purified with a silica gel column to obtain 151 g of the compound of B-6.

The compound of B-6 (150 g, 0.29 mol) and triethylamine (88 g, 0.88 mol) were added to 1 kg of dry tetrahydrofuran and cooled to 0 to 5 ° C., and then acryloyl chloride (80 g, 0.88 mol) was slowly added dropwise. After completion of the dropwise addition, the temperature was slowly returned to room temperature and stirred at room temperature for 6 hours. The reaction solution was poured into water, neutralized, extracted with ethyl acetate, and the organic layer was dried over anhydrous sodium sulfate. Thereafter, the solvent was distilled off under reduced pressure to obtain 172 g of a crude B-7 compound.
The compound (5 g) of the crude product B-7 was dissolved in 10 ml of toluene, and 3 g of activated clay (manufactured by Mizusawa Chemical Co., Ltd .: trade name: Galeonite # 212) was added thereto and stirred at room temperature for 60 minutes. The activated clay was filtered using a 1 μm filter paper, and then filtered using a 0.2 μm membrane filter. The filtrate was removed under reduced pressure to obtain 4.7 g of the purified product B-7 compound (viscous liquid).
Next, the obtained purified product B-7 was used as a photoreceptor in the same manner as in Example 1 for evaluation. The results are shown in Table 3.
(Example 12)
The compound of refined product B-7 was treated in the same manner as in Example 1 except that the activated clay in Example 11 was replaced with acid clay (made by Mizusawa Chemical Co., Ltd .: trade name; Mizuka Ace # 300). 4 g was obtained. Next, the obtained purified product B-7 was used as a photoreceptor in the same manner as in Example 1 for evaluation. The results are shown in Table 3.
(Example 13)
Except that the activated clay of Example 11 was replaced with a silica-magnesia-based adsorbent (manufactured by Mizusawa Chemical Co., Ltd .: trade name; Mizuka Life P-1), it was treated in the same manner as in Example 1, and purified product B- 4.2 g of 7 compound was obtained. Next, the obtained purified product B-7 was used as a photoreceptor in the same manner as in Example 1 for evaluation. The results are shown in Table 3.
(Example 14)
40 g of alumina oxide (manufactured by Merck Co., Ltd .: trade name; Aluminum oxide 90, activ acidic) was packed in a column (20 mmΦ), and the compound (4.0 g) of the purified product B-7 obtained in Example 12 was toluene. It melt | dissolved in 20 ml and refine | purified using the toluene / ethyl acetate (10/1) mixed solvent as a developing solvent, and the compound (3.0g) of the further purified product B-7 was obtained. Next, the obtained further purified product B-7 was used as a photoreceptor in the same manner as in Example 1 for evaluation. The results are shown in Table 3.
(Example 15)
By the following step (C), the compound Nos. One charge transporting compound was synthesized and purified.

  In step (C), C-1 compound (180 g, 0.62 mol), C-2 compound (82 g, 0.416 mol), anhydrous potassium carbonate (135 g) and copper powder (110 g) The mixture was stirred with chlorobenzene (1.0 kg) at 180 to 190 ° C. for 12 hours. After filtering the reaction solution, the solvent was removed under reduced pressure. Excess C-1 compound in the residue was removed by distillation under reduced pressure, and then added to 800 g of ethanol, and caustic soda (20 g) was slowly added while stirring at room temperature. After completion of the addition, the mixture was stirred as it was at room temperature for 1 hour, and further heated and stirred at 70 to 80 ° C. for 7 hours. The reaction mixture was poured into water, neutralized with dilute hydrochloric acid, extracted with ethyl acetate, the organic layer was dried over anhydrous sodium sulfate, and the solvent was removed under reduced pressure to obtain 110 g of C-4 compound.

A compound of C-4 (100 g: 0.315 mol), acrylic acid (27 g: 0.375 mol) and P-methoxyphenol (100 mg) were dissolved in toluene (300 g), and then P-toluenesulfonic acid (monohydrate) ( 0.8 g) was added at room temperature. Thereafter, the mixture was heated in an oil bath and dehydrated and refluxed for 7 hours. The reaction solution was poured into ice water, neutralized with 10% caustic soda and extracted with ethyl acetate. The organic layer was washed with water and dried over anhydrous magnesium sulfate. Thereafter, the solvent was distilled off under reduced pressure to obtain 112 g of a crude product C-5 compound.
The compound (5 g) of the crude product C-5 was dissolved in 10 ml of toluene, 5 g of activated clay (manufactured by Kishida Chemical Co., Ltd.) was added thereto, and the mixture was stirred for 15 minutes at room temperature. The activated clay was filtered using a 1 μm filter paper and further filtered using a 0.5 μm membrane filter. The filtrate was removed under reduced pressure to obtain 4.7 g of purified product C-5 compound (viscous liquid).
Next, the obtained purified product C-5 was used as a photoreceptor in the same manner as in Example 1 for evaluation. The results are shown in Table 3.
(Example 16)
The compound of purified product C-5 was treated in the same manner as in Example 15 except that the activated clay in Example 15 was replaced with acid clay (trade name; Mizuka Ace # 300, manufactured by Mizusawa Chemical Co., Ltd.). 4 g was obtained.

Next, the obtained purified product C-5 was used as a photoreceptor in the same manner as in Example 1 for evaluation. The results are shown in Table 3.
(Example 17)
The activated clay of Example 15 was treated in the same manner as in Example 15 except that the activated clay was replaced with a silica-magnesia-based adsorbent (manufactured by Mizusawa Chemical Co., Ltd .; trade name; Mizuka Life P-1). 4.3 g of compound 5 was obtained. Next, the obtained purified product C-5 was used as a photoreceptor in the same manner as in Example 1 for evaluation. The results are shown in Table 3.
(Example 18)
40 g of silica gel (Fuji Silysia Chemical Co., Ltd .: trade name BW-300) was packed in a column (20 mmΦ), and the purified product C-5 compound (4.0 g) obtained in Example 15 was dissolved in 20 ml of toluene. Further purification was performed using toluene as a developing solvent to obtain a purified product C-5 compound (3.5 g). Next, the obtained purified product C-5 was used as a photoreceptor in the same manner as in Example 1 for evaluation. The results are shown in Table 3.
(Example 19)
Compound Example Nos. The crude product of No. 7 (5 g) was dissolved in 10 ml of toluene, and 1 g of activated clay (manufactured by Mizusawa Chemical Co., Ltd .: trade name; Galeonite # 212) was added thereto and stirred at room temperature for 60 minutes. The activated clay was filtered using a 1 μm filter paper, and then filtered using a 0.2 μm membrane filter. The filtrate was removed under reduced pressure to obtain 4.7 g of a purified product (viscous liquid). Next, using the obtained purified product, it was evaluated as a photoreceptor in the same manner as in Example 1. The results are shown in Table 3.
(Example 20)
Compound Example Nos. 15 crude products (5 g) were dissolved in 10 ml of toluene, and 5 g of activated clay (manufactured by Mizusawa Chemical Co., Ltd .: trade name: Galeonite # 212) was added thereto and stirred at room temperature for 60 minutes. The activated clay was filtered using a 1 μm filter paper, and then filtered using a 0.2 μm membrane filter. The filtrate was removed under reduced pressure to obtain 4.5 g of a purified product (viscous liquid). Next, using the obtained purified product, it was evaluated as a photoreceptor in the same manner as in Example 1. The results are shown in Table 3.
(Comparative Example 1)
The compound (5 g) of the crude product A-5 obtained in Example 1 was dissolved in 10 ml of toluene, and 5 g of silica gel (manufactured by Fuji Silysia Chemical Co., Ltd .: trade name BW-200) was added thereto for 30 minutes at room temperature. Stir processing was performed. The silica gel was filtered using a 1 μm filter paper and further filtered using a 0.5 μm membrane filter. The filtrate was removed under reduced pressure to obtain 4.7 g of the purified product A-5 compound. Next, the obtained purified product A-5 was used as a photoreceptor in the same manner as in Example 1 for evaluation. The results are shown in Table 4.

(Comparative Example 2)
The crude product A-5 compound (5 g) obtained in Example 1 was dissolved in 10 ml of toluene, and 5 g of alumina oxide (manufactured by Merck Co., Ltd .: trade name; Aluminum oxide 90, activ acidic) was added thereto. Stirred at room temperature for minutes. The alumina oxide was filtered using a 1 μm filter paper and further filtered using a 0.5 μm membrane filter. The filtrate was removed under reduced pressure to obtain 4.6 g of the purified product A-5 compound. Next, the obtained purified product A-5 was used as a photoreceptor in the same manner as in Example 1 for evaluation. The results are shown in Table 4.
(Comparative Example 3)
The compound (5 g) of the crude product A-5 obtained in Example 1 was dissolved in 10 ml of toluene, and 5 g of activated carbon (manufactured by Takeda Pharmaceutical Co., Ltd .: trade name; Purified Shirasagi P) was added thereto for 30 minutes at room temperature. And stirred. The activated carbon was filtered using a 1 μm filter paper and further filtered using a 0.5 μm membrane filter. The filtrate was removed under reduced pressure to obtain 4.6 g of the purified product A-5 compound. Next, the obtained purified product A-5 was used as a photoreceptor in the same manner as in Example 1 for evaluation. The results are shown in Table 4.
(Comparative Example 4)
40 g of silica gel (manufactured by Fuji Silysia Chemical Co., Ltd .: trade name BW-200) was packed in a column (20 mmΦ), and the compound (4.0 g) of crude product A-5 obtained in Example 1 was dissolved in 20 ml of toluene. Then, purification was performed using toluene as a developing solvent, and 3.4 g of the compound of purified product A-5 was obtained. Next, the obtained purified product A-5 was used as a photoreceptor in the same manner as in Example 1 for evaluation. The results are shown in Table 4.
(Comparative Example 5)
40 g of alumina oxide (Merck Co., Ltd .: trade name; Aluminum oxide 90, activ acidic) was packed in a column (20 mmΦ), and the compound (4.0 g) of the crude product A-5 obtained in Example 1 was toluene. It melt | dissolved in 20 ml and refine | purified using the toluene / ethyl acetate (10/1) mixed solvent as a developing solvent, and 3.2g of compounds of the refined product A-5 were obtained. Next, the obtained purified product A-5 was used as a photoreceptor in the same manner as in Example 1 for evaluation. The results are shown in Table 4. (Comparative Example 6)
The compound (5 g) of the crude product B-7 obtained in Example 11 was dissolved in 10 ml of toluene, and 3 g of silica gel (manufactured by Fuji Silysia Chemical Co., Ltd .: trade name BW-200) was added thereto for 60 minutes at room temperature. Stir processing was performed. The silica gel was filtered using a 1 μm filter paper and further filtered using a 0.2 μm membrane filter. The filtrate was removed under reduced pressure to obtain 4.7 g of the purified product B-7 compound (viscous liquid). Next, the obtained purified product B-7 was used as a photoreceptor in the same manner as in Example 1 for evaluation. The results are shown in Table 4.
(Comparative Example 7)
The crude product B-7 compound (5 g) obtained in Example 11 was dissolved in 10 ml of toluene, and 3 g of alumina oxide (Merck, Inc .: trade name; Aluminum oxide 90, activ acidic) was added thereto. Stirred at room temperature for minutes. The alumina oxide was filtered using a 1 μm filter paper and further filtered using a 0.2 μm membrane filter. The filtrate was removed under reduced pressure to obtain 4.5 g of purified product B-7 compound (viscous liquid). Next, the obtained purified product B-7 was used as a photoreceptor in the same manner as in Example 1 for evaluation. The results are shown in Table 4.
(Comparative Example 8)
40 g of silica gel (manufactured by Fuji Silysia Chemical Co., Ltd .: trade name BW-200) was packed in a column (20 mmΦ), and the compound (4.0 g) of the crude product B-7 obtained in Example 11 was dissolved in 20 ml of toluene. Then, purification was performed using toluene as a developing solvent to obtain 3.3 g of the purified product B-7 compound. Next, the obtained purified product B-7 was used as a photoreceptor in the same manner as in Example 1 for evaluation. The results are shown in Table 4.
(Comparative Example 9)
40 g of alumina oxide (manufactured by Merck Co., Ltd .: trade name; Aluminium oxide 90, activ acidic) was packed in a column (20 mmΦ), and the compound (4.0 g) of the crude product B-7 obtained in Example 11 was used. It melt | dissolved in 20 ml of toluene, it refine | purified using the toluene / ethyl acetate (10/1) mixed solvent as a developing solvent, and 3.0g of compounds of the refined product B-7 were obtained. Next, the obtained purified product B-7 was used as a photoreceptor in the same manner as in Example 1 for evaluation. The results are shown in Table 4.
(Comparative Example 10)
The crude product C-5 compound (5 g) obtained in Example 15 was dissolved in 10 ml of toluene, and 5 g of silica gel (Fuji Silysia Chemical Co., Ltd .: trade name BW-300) was added thereto for 15 minutes at room temperature. Stir processing was performed. The silica gel was filtered using a 1 μm filter paper and further filtered using a 0.5 μm membrane filter. The filtrate was removed under reduced pressure to obtain 4.7 g of the purified product C-5 compound. Next, the obtained purified product C-5 was used as a photoreceptor in the same manner as in Example 1 for evaluation. The results are shown in Table 4.
(Comparative Example 11)
40 g of silica gel (Fuji Silysia Chemical Co., Ltd .: trade name BW-300) was packed in a column (20 mmΦ), and the crude product C-5 compound (4.0 g) obtained in Example 15 was dissolved in 20 ml of toluene. Then, purification is performed using toluene as a developing solvent, and the compound of the purified product C-5 is obtained as 3.
5 g was obtained. Next, the obtained purified product C-5 was used as a photoreceptor in the same manner as in Example 1 for evaluation. The results are shown in Table 4.
(Comparative Example 12)
40 g of silica gel (Fuji Silysia Chemical Co., Ltd .: trade name BW-300) was packed in a column (20 mmΦ), and the compound example No. 4.0 g of the crude product 7 was dissolved in 20 ml of toluene and purified using toluene as a developing solvent to obtain 3.5 g of a purified product. Next, using the obtained purified product, it was evaluated as a photoreceptor in the same manner as in Example 1. The results are shown in Table 4.
(Comparative Example 13)
40 g of silica gel (Fuji Silysia Chemical Co., Ltd .: trade name BW-300) was packed in a column (20 mmΦ), and the compound example No. 4.0 g of 15 crude product was dissolved in 20 ml of toluene and purified using toluene as a developing solvent to obtain 3.3 g of purified product. Next, using the obtained purified product, it was evaluated as a photoreceptor in the same manner as in Example 1. The results are shown in Table 4.
(Comparative Example 14)
In the synthesis of Example 1, the following compound (D-1) was synthesized using the same method except that 3,4-xylidine (A-1) was replaced by aniline to obtain a crude product.

The obtained crude product (5 g) was dissolved in 10 ml of toluene, 5 g of activated clay (manufactured by Kishida Chemical Co., Ltd.) was added thereto, and the mixture was stirred at room temperature for 30 minutes. The activated clay was filtered using a 1 μm filter paper and further filtered using a 0.5 μm membrane filter. The filtrate was removed under reduced pressure to obtain 4.7 g of a purified product (viscous liquid). Next, using the obtained purified product, it was evaluated as a photoreceptor in the same manner as in Example 1. The results are shown in Table 4.
(Comparative Example 15)
Except that the activated clay in Comparative Example 14 was replaced with acid clay (manufactured by Mizusawa Chemical Co., Ltd .: trade name; Mizuka Ace # 300), the same treatment as in Comparative Example 14 was performed to obtain 4.5 g of a purified product. Next, using the obtained purified product, it was evaluated as a photoreceptor in the same manner as in Example 1. The results are shown in Table 4.
(Comparative Example 16)
The refined product was treated in the same manner as in Comparative Example 14 except that the activated clay of Comparative Example 14 was replaced with a silica-magnesia-based adsorbent (manufactured by Mizusawa Chemical Co., Ltd .: trade name; Mizuka Life P-1). .4 g was obtained. Next, using the obtained purified product, it was evaluated as a photoreceptor in the same manner as in Example 1. The results are shown in Table 4.
(Comparative Example 17)
A crude product (5 g) of the following structural formula (D-2) was dissolved in 10 ml of toluene, 5 g of activated clay (manufactured by Kishida Chemical Co., Ltd.) was added thereto, and the mixture was stirred for 30 minutes at room temperature. The activated clay was filtered using a 1 μm filter paper and further filtered using a 0.5 μm membrane filter. The filtrate was removed under reduced pressure to obtain 4.7 g of a purified product (viscous liquid).

Next, using the obtained purified product, it was evaluated as a photoreceptor in the same manner as in Example 1. The results are shown in Table 4.
(Comparative Example 18)
The activated clay of Comparative Example 17 was acid clay (Mizusawa Chemical Co., Ltd .: trade name; Mizuka Ace # 300)
) Was processed in the same manner as in Comparative Example 17 except that 4.5) was obtained. Next, using the obtained purified product, it was evaluated as a photoreceptor in the same manner as in Example 1. The results are shown in Table 4.
(Comparative Example 19)
The purified white clay was treated in the same manner as in Comparative Example 17 except that the activated clay in Comparative Example 17 was replaced with a silica / magnesia-based adsorbent (manufactured by Mizusawa Chemical Co., Ltd .: trade name; Mizuka Life P-1). .3 g was obtained. Next, using the obtained purified product, it was evaluated as a photoreceptor in the same manner as in Example 1. The results are shown in Table 4.
(Comparative Example 20)
A crude product (5 g) of the following structural formula (D-3) is dissolved in 10 ml of toluene, and 5 g of activated clay (produced by Mizusawa Chemical Co., Ltd .: trade name; Galeon Earth # 136) is added thereto and stirred at room temperature for 30 minutes. Processed. The activated clay was filtered using a 1 μm filter paper and further filtered using a 0.5 μm membrane filter. The filtrate was removed under reduced pressure to obtain 4.5 g of a purified product (viscous liquid).

Next, using the obtained purified product, it was evaluated as a photoreceptor in the same manner as in Example 1. The results are shown in Table 4.
(Comparative Example 21)
A crude product (5 g) of the following structural formula (D-4) was dissolved in 10 ml of toluene, and 5 g of activated clay (made by Mizusawa Chemical Co., Ltd .: trade name; Galeon Earth # 136) was added thereto and stirred at room temperature for 30 minutes. Processed. The activated clay was filtered using a 1 μm filter paper and further filtered using a 0.5 μm membrane filter. The filtrate was removed under reduced pressure to obtain 4.6 g of a purified product (viscous liquid).

  Next, using the obtained purified product, it was evaluated as a photoreceptor in the same manner as in Example 1. The results are shown in Table 4.

Claims (8)

A charge transporting compound having a triphenylamine structure represented by the following general formula (1) and having at least one chain polymerizable functional group is dissolved in an organic solvent, and the charge transporting compound-containing organic solvent is activated. Contact with at least one adsorbent selected from silica / alumina adsorbents of white clay and acidic clay and silica / magnesia adsorbents, and then separate the adsorbent and the organic solvent containing the charge transporting compound. Next, a method for purifying a charge transporting compound, wherein a purified product of the charge transporting compound is obtained by removing the organic solvent from the organic solvent.

(In the formula (1), Ar ¹ , Ar ² and Ar ³ represent phenyl groups, and each phenyl group has a substituent at the para position with respect to the nitrogen atom.) The method for purifying a charge transporting compound according to claim 1, wherein the chain polymerizable functional group is any one of the following general formulas (2) to (6).

  The method for purifying a charge transporting compound according to claim 1 or 2, wherein the charge transporting compound represented by the general formula (1) is a liquid at 20 ° C or higher.   The method for purifying a charge transporting compound according to any one of claims 1 to 3, further comprising contacting silica gel or alumina after contacting with activated clay. The method for purifying a charge transporting compound according to any one of claims 1 to 4, wherein the charge transporting compound represented by the general formula (1) has at least two chain polymerizable functional groups. The method for purifying a charge transporting compound according to any one of claims 1 to 5, wherein the charge transporting compound represented by the general formula (1) is represented by the following general formula (7).

(In formula (7), R ₁ , R ₂ and R ₃ each represents an alkyl group, an aralkyl group or an aryl group which may have a substituent, and may be the same or different. Each independently represents an integer of 0 to 3. P ₁ , P ₂ and P ₃ each represent a chain polymerizable functional group, a, b and c each independently represent an integer of 0 to 4, n, m and l represents an integer of 0 to 2, and n + m + 1 represents an integer of at least 1 and the products of n and y, m and x, and l and z are not 0. In addition, any phenyl group of triphenylamine is (It has a substituent in the para position to the nitrogen atom.)   The method for purifying a charge transporting compound according to any one of claims 1 to 6, wherein an oxidation potential of the charge transporting compound represented by the general formula (1) is 0.75 (v) or more. In an electrophotographic photosensitive member having a photosensitive layer provided on a conductive support,
The photosensitive layer forms the surface of the electrophotographic photosensitive member and is composed of a single layer or a plurality of stacked layers,
The purification method according to any one of claims 1 to 7, wherein the layer forming the surface of the electrophotographic photoreceptor among the photosensitive layer constituted by a single layer or the photosensitive layer constituted by a plurality of layers is used. An electrophotographic photoreceptor comprising a charge transporting compound purified using