JPH0378872B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel method for producing x-type metal-free phthalocyanine with high purity, in which phthalonitrile is reacted in the presence of a strong base to produce metal-free phthalocyanine. After solubilizing it in a solvent, it is purified using a solvent, then restored to obtain high-purity metal-free phthalocyanine, and then the crystal structure is converted to an x-type crystal structure using a ball mill to obtain the target product in high yield. This is what you are trying to obtain. <Industrial Application Fields> Since phthalocyanine compounds have semiconducting properties and photoconductivity, much research has been conducted in recent years. For example, active research is being conducted to apply photoconductivity to electrophotographic photoreceptors or photoreceptors for semiconductor laser printers. The x-type metal-free phthalocyanine is disclosed in U.S. Patent No.
It is one of the crystal forms of metal-free phthalocyanine that can take various crystal forms and is disclosed in the specification of No. 3557989, and because it has high photosensitivity, it can be applied to electrophotographic photoreceptors and its use. Since the absorption wavelength extends into the near-infrared region, it is expected to be applied to photoreceptors for laser printers. <Prior art and its limitations> As a manufacturing method, U.S. Patent No. 3,357,989 discloses α-type metal-free phthalocyanine (hereinafter referred to as α-H ₂ P), which is purified by dissolving a commercially available pigment in sulfuric acid and precipitating it in ice water. It describes a method for ball milling (abbreviated as _C ) for 7 days. In Japanese Patent Publication No. 45-8102, commercially available α-H ₂ P _C
contains a small amount of x-type metal-free phthalocyanine (hereinafter x-
A method for producing x-H ₂ P _C is described in which x-H ₂ P _C is added (abbreviated as H 2 P C) and ball milled in an aliphatic solvent having a carbonyl group such as methyl ethyl ketone. However, according to the former method, commercially available α-
When x-H ₂ P _C is produced using H ₂ P _C as a starting material, as shown in Comparative Example 1 below, the α-type crystal form often remains as it is even after long-term milling, making it stable. It is not possible to obtain an x-type crystal. Moreover, when x-H ₂ P _C is produced according to the latter method, as shown in Comparative Example 2, the x-type crystal is not obtained, but the β-type crystal is often obtained, and the x-type crystal is not obtained. Similar to the former method, it is not possible to stably obtain the shape. On the other hand, as a method for purifying phthalocyanines, as also shown in the above-mentioned US Pat. No. 3,357,989, after dissolving the pigment phthalocyanine in sulfuric acid,
A so-called acid pasting method in which dilithium phthalocyanine is precipitated in ice water, a sublimation purification method under reduced pressure, a purification method that utilizes the dissolution of dilithium phthalocyanine in alcohol, or the method described in U.S. Patent No. 4197242 Purification methods using solvent-soluble phthalocyanine complexes such as the dipotassium phthalocyanine bis(methoxyethyl) ether described above are known. However, no matter which method is used, it is impossible to stably produce x-H _{2 PC} from pigment-free metal phthalocyanine. Moreover, the obtained x-
H ₂ P _C often has poor optoelectronic properties, making it difficult to use it industrially as an organic photoconductive material. Furthermore, as an improved method for producing metal-free phthalocyanine (hereinafter abbreviated as H ₂ P _C ) for application to such photoconductive materials, phthalonitrile is converted into 1,8-diazabicyclo[5,4, 0] Undecene-7 (hereinafter abbreviated as DBU) or 1,5-
Diazabicyclo[4,3,0]nonene-5 (hereinafter
A method is known in which a heating reaction is carried out in an alcohol solvent in the presence of DBN (abbreviated as DBN) (Japanese Patent Laid-Open No. 58
-105962). Compared to conventional methods, this production method allows the reaction to occur at a relatively low temperature, so H ₂ P _C with relatively high purity can be obtained. however,
According to additional tests conducted by the present inventors, the metal-free phthalocyanine obtained by this method contains DBU _{or DBN} or their decomposition products, which are difficult to remove. x obtained by converting
-H ₂ P _C often has high conductivity in the dark, making it difficult to obtain x-H ₂ P _C that exhibits stable and good characteristics. <Problems to be solved by the invention> As described above, in the prior art, it is not possible to stably produce x-H ₂ P _C , or even if it is possible, the obtained x-H ₂ A serious problem is that the electrical and electronic properties of _PC are less than desirable. <Means for Solving the Problems> The present inventors conducted extensive studies to investigate the causes of such inconveniences in the conventional technology, and found that
It has been found that there is a problem with the purity of H ₂ P _C , and that it is important to increase this purity to 95% or more, preferably 97.5% or more. In other _{words ,} x-
H ₂ P _C can be stably produced and the obtained x-H ₂ P _C
The present invention was completed by discovering that this material exhibits stable and excellent electrical and electronic properties. That is, the present invention relates to a new method for producing high-purity x-H ₂ P _C , and more particularly,
The reaction is carried out in the presence of a strong base such as DBU or DBN to produce metal-free phthalocyanine, the obtained crude product is subjected to solvent solubilization treatment, and the obtained solubilized product is purified with a solvent to obtain the The method is characterized in that highly pure metal-free phthalocyanine is obtained by restoring the purified solubilized material, and then the original crystal structure is converted into an x-type crystal structure by ball milling it. , relates to a method for producing high purity x-type metal-free phthalocyanine. In the present invention, phthalonitrile, DBU or
A commercially available industrial product may be used as DBN. or,
High purity products purified by purification means such as recrystallization and distillation can also be used. The strong base is preferably DBU and DBN because they are easy to handle, but is not necessarily limited to them, and may also be an alkali metal alcoholate or 1,4-diazabicyclo[2,2,2]octane (abbreviated as DABCO). Any substance that has basicity at least as strong as DABCO in an organic solvent can be used. As a solvent, an organic compound having a hydroxyl group is mainly used, and an aliphatic straight chain alcohol is particularly preferable, and an alcohol having 1 to 8 carbon atoms is more preferable, and 2-methoxyethanol, 2-methoxyethanol, 2-
Ethylene glycol monoalkyl ethers such as ethoxyethanol and 2-n-butoxyethanol may also be used. In carrying out the present invention, there are no particular restrictions on the mixture in the above-mentioned proportions, but preferably 0.1 mol or more of DBU or DBN and 200 ml or more of the solvent are used per 1 mol of phthalonitrile. Furthermore, although the reaction may be carried out by mixing the three components at the same time, adding the strong base in portions after heating the mixed system of phthalonitrile and solvent to a predetermined temperature will affect the purity of H ₂ P _C. This is the preferred method for increasing Furthermore, the method of adding DBU or DBN in portions makes it possible to increase the concentration of phthalonitrile and improves the yield per batch, so it is a desirable method from an industrial standpoint. The reaction temperature is preferably below the reflux temperature of the solvent, and is usually selected from 65 to 195°C. Although the reaction time varies depending on the solvent, it is generally sufficient to react for 30 minutes to 24 hours. The H ₂ P _C produced by such a method is separated from the solvent by a conventional method, washed with an appropriate solvent such as alcohol or ketones, then water or a dilute mineral acid aqueous solution, and dried. urge H ₂ P _C obtained at this stage often has a β-type crystal structure. The obtained crude H ₂ P _C is solubilized in a solvent under heating. Two methods can be selected for this solvent solubilization. The first method is to use dilithium phthalocyanine (hereinafter abbreviated as Li ₂ Pc) as H ₂ P _C and dissolve it in alcohol. The lithiation agents that can be used in this process include metallic lithium,
Lithium alcoholate, lithium hydride,
Examples include n-butyllithium and lithium diisopropylamide. There are no particular restrictions on the alcohol, but straight chain alcohols are generally preferred. Of course, ethylene glycol monoalkyl ethers such as 2-methoxyethanol, 2-ethoxyethanol, and 2-n-butoxyethanol can also be used. There are no particular restrictions on the mixing ratio, reaction temperature, reaction time, etc., but preferably at a room temperature of 150°C in a ratio of 1 to 3 moles of lithiation agent and 1 to 20 moles of alcohol to 514 g of crude H ₂ Pc. It is recommended to react for 10 minutes to 5 hours. When such a lithiation reaction is completed, solvent-insoluble substances are present in the system. This is clearly recognized as an impurity, so it is separated. Furthermore, if there is a possibility that impurities may be dissolved in the solvent, cool the liquid containing Li ₂ Pc and remove the precipitated Li ₂ Pc.
It is also effective to separate the Of course, dissolved impurities may be precipitated and separated by appropriate means prior to the precipitation of Li ₂ Pc. Li ₂ Pc from which impurities have been removed is easily decomposed by adding water, dilute mineral acid aqueous solution, carbon dioxide gas, dry ice, etc. to the solution in the solvent,
Restore to original _H2 Pc. The second method is to convert H ₂ Pc into dipotassium phthalocyanine, form a complex with a solvent, and solubilize it in the solvent. Such complexes include, for example, J.Am.
Chem. Soc., 103 , 4629 (1981), dipotassium phthalocyanine dicrown ether complex, dipotassium phthalocyanine bis(methoxyethyl) ether complex (hereinafter abbreviated as K ₂ Pc (diglyme) ₂ ), or Inorg. Chem, 20 , 2709 (1981)
or the dipotassium phthalocyanine tetradimethylformamide complex described in U.S. Pat.
Examples include the dipotassium phthalocyanine tetraglyme complex and the dipotassium phthalocyanine dimethyl sulfoxide complex described in No. 4197242, and any complex may be used.
Due to the ease of the process, the method via K ₂ Pc (diglyme) ₂ is recommended. In this step, potassium hydroxide, potassium hydroxide, potassium alkoxide, tert-butoxypotassium, etc. can be used as the potassium forming agent. Further, potassium hydroxide can be used as a solid or an aqueous solution. More preferably, it is used in a coexisting state of solid and aqueous solution. The method of coexisting solid and aqueous solution improves the yield per batch, eliminates the need to dry diglyme, and requires less amount of waste potassium hydroxide aqueous solution, resulting in lower neutralization costs. , the advantages from an industrial standpoint are many. When carrying out this step, there are no particular restrictions on the charging ratio, reaction method, etc., but usually crude phthalocyanine
It is preferable that the amount of potassium forming agent is 2 moles or more and the amount of diglyme is 2 moles or more per 514 g. When using an aqueous potassium hydroxide solution as a potassium converting agent, it is preferable to adjust the concentration of potassium hydroxide at the time of preparation to be 50% or more and the concentration after the reaction is 40% or more. Because of this, K ₂ Pc
Precipitation of (diglyme) ₂ is not preferable, and it is preferable to use 10 moles or more of diglyme. Furthermore, when solid potassium hydroxide and aqueous solution coexist, 2 moles or more of solid potassium hydroxide and 60% aqueous potassium hydroxide solution are added per 514 g of crude phthalocyanine.
It is preferable to use 100 g or more and 10 moles or more of diglyme. There are no particular restrictions on the reaction temperature and time, and the reaction takes place at a relatively low temperature and in a short period of time. Preferably room temperature ~150
The reaction is carried out at a temperature of 5 minutes to 5 hours. When using an aqueous potassium hydroxide solution or an aqueous solution and a solid, the temperature is preferably 100°C or less. The impurities contained in the system of the dipotassium phthalocyanine solvent complex obtained _in this way are
It can be easily and reliably removed in the same way as in the case of . The purified dipotassium phthalocyanine solvent complex is then restored to the original H ₂ Pc in the same manner as Li ₂ Pc. The H ₂ Pc purified by such means is separated from the solvent by a conventional method and treated with a suitable solvent such as alcohol, ketones, ethers, etc.
It is then washed with water and dried. H ₂ Pc obtained in this step often has an α-type crystal structure. Further, although such a purification step can normally be carried out once, it is preferable to carry out it twice or more when higher purity is required. The appropriate purity is 95% or more, preferably 97.5% or more. The purified high purity H ₂ Pc is then converted into the x-form, crystalline form, by ball milling. In the present invention, x-H ₂ Pc is 7.5, 9.1,
Although it has an X-ray diffraction pattern with strong lines at 16.7, 17.3, and 22.3 degrees, the intensity ratio does not necessarily match the pattern described in U.S. Pat. No. 3,357,989 shown in FIG. do not have. In carrying out the present invention, the ball mill and balls may be made of any material, but in order to minimize the contamination of metal impurities, stainless steel,
It is preferable to use ceramics, glass, agate, or the like. The amount of high-purity H ₂ Pc and balls to be charged, the rotation speed of the ball mill, the ball milling time, temperature, etc. vary depending on the size of the ball mill and the diameter of the balls to be prepared, and cannot be generalized, but for example, a diameter of 90 mmφ, Internal volume 400ml
A ceramic ball mill made of the same material has a diameter of 10 mm.
When 400 g of mmφ balls and 20 g of high-purity α-H ₂ Pc are charged and rotated at room temperature at a rotation speed of 100 rpm, the crystal structure is 100% converted to an x-type crystal structure in about 72 hours. Ball milling is neat milling or
Of course, salt milling with the addition of sodium chloride, etc., which is not inconvenient as an additive, or wet milling with the addition of ethylene glycol, water, etc., may also be used. Milling time can be determined by a specific milling method or by changing the volume of a ball mill by taking out a portion of the sample at regular intervals and using analytical means such as infrared spectroscopy, visible absorption spectroscopy, or X-ray diffraction. can. <Effects of the Invention> The present invention can stably achieve x using a simple method as described above.
−H ₂ Pc can be produced, and furthermore, it is stable,
This is an excellent method that shows excellent electrical and electronic properties. <Examples, etc.> The present invention will be specifically explained below using Examples, Comparative Examples, and Reference Examples, but the scope of the present invention is not limited thereby. Example 1 512.6 g of phthalonitrile and 2-methoxyethanol were charged into a 3-glass four-neck flask equipped with a stirrer, a dropping funnel, a reflux condenser, a thermometer, and a nitrogen gas inlet tube, and the mixture was heated under a nitrogen gas atmosphere. , heated on an oil bath and held at reflux temperature. When the reflux temperature was reached, DBU was started to be added dropwise from the dropping funnel, and 608.6 g was added over a period of 2 hours. The reaction was further carried out under reflux for 14 hours. After the reaction, it was cooled to room temperature and filtered to obtain reddish-purple crystals, which were mixed with 1 part of 2-methoxyethanol and then 4 parts of water.
, and further washed with 1 portion of acetone and dried to obtain 359.3 g of reddish-purple microcrystals. From this X-ray diffraction and infrared absorption spectrum measurements, the product obtained was β-H ₂ Pc. Furthermore, as a result of purity analysis,
It contained 92.5% _H2Pc . Next, 200 g of the obtained crude β-H ₂ Pc was placed in a second four-necked flask equipped with a stirrer, a dropping funnel, a thermometer, a nitrogen gas introduction tube, and a ball filter.
was charged with 1000 g of diglyme, 200 g of a 62% aqueous potassium hydroxide solution, and 51.4 g of granular potassium hydroxide, and reacted for 30 minutes at a temperature of 80° C. under a nitrogen gas atmosphere. As the reaction progresses, the diglyme layer takes on a green color. 30 minutes after the completion of the reaction, leave it at a temperature of 80℃,
The diglyme and aqueous layers were separated. Next, the diglyme layer was suctioned through a ball filter and a glass filter, and the liquid was immediately introduced into 500 g of a 5% aqueous hydrochloric acid solution, and under strong stirring, K ₂ Pc
(diglyme) ₂ was decomposed. The resulting blue slurry was filtered, washed with warm water until the liquid became neutral, and then diluted with acetone 3
By washing with water and drying under reduced pressure under heat, 185.9 g of blue fine powder was obtained. Further, the above operation was repeated using this entire amount, and 182.2 g of blue fine powder was obtained. According to X-ray diffraction and infrared absorption spectrum, this blue powder was α-H ₂ Pc with a purity of 99% or more. 20.0 g of this high-purity α-H ₂ Pc was placed in an alumina ball mill with an outer diameter of 90 mmφ and an internal volume of 400 ml, and after adding 400 g of alumina balls with an outer diameter of 10 mmφ, milling was carried out at room temperature at a rotation speed of 100 rpm for 100 hours. Summer. The contents were scraped out and passed through a 50 mesh sieve to obtain 17.2 g of bluish reddish-purple powder. According to X-ray diffraction and infrared absorption spectrum, this powder has x-
It was H ₂ Pc. The X-ray diffraction diagram is shown in FIG. Example 2 20.0 g of high purity α-H ₂ Pc obtained in Example 1 was milled in the same manner. This operation was repeated 7 times. When each batch was analyzed by X-ray diffraction and infrared absorption spectrum, the powder obtained in each batch was all x-H ₂ Pc, with _good reproducibility. obtained. It is clear how superior this method is compared to Comparative Examples 1 to 3. Comparative Example 1 Pigment α-H ₂ Pc (BASF, trade name: Heliogen)
blne L7560) 20.0g, outer diameter 90mmφ, inner volume 400ml
After adding 400g of alumina balls with an outer diameter of 10mmφ into an alumina ball mill, at room temperature,
Milling was carried out for 100 hours at a rotation speed of 100 rpm.
Analysis results by X-ray diffraction and infrared absorption spectrum showed that it was an α-type crystal. Further, 20.0 g of the same pigment α-H ₂ Pc was dissolved little by little in 200 g of 98% sulfuric acid cooled to 5°C, and the mixture was stirred for 2 hours while maintaining the temperature at 5°C.
Next, this sulfuric acid solution was poured into ice water in step 4,
The precipitated crystals were separated and washed with water until the liquid became neutral. After drying, purified α-H ₂ Pc
Obtained 15.6g. 15.0 g of this purified α-H ₂ Pc was milled in the same manner as above, and a small amount was taken out at 100 and 200 hours and analyzed by X-ray diffraction.
- remained in the -type crystal form. That is, in the case of α-H ₂ Pc used here, the so-called acid base method is ineffective. Comparative Example 2 In the first ball mill similar to that used in Example 1, pigment α-H ₂ Pc (BASF, trade name Heliogen) was added.
blne L7560), 0.25 g of x-H ₂ Pc, and 100 g of methyl ethyl ketone were charged. Second, _4.75 g of α-H ₂ Pc, x-
0.25 g of H ₂ Pc and 100 g of methyl ethyl ketone were charged. Thirdly, the high purity α- obtained in Example 1
4.75 g of H ₂ Pc, 0.25 g of x-H ₂ Pc and 100 g of methyl ethyl ketone were charged. Milling was carried out using these ball mills at a room temperature of 25° C. and a rotation speed of 100 rpm. When samples were taken every hour and traced by X-ray diffraction, x-H ₂ Pc was not obtained in any case, and in the first method, the α-type crystal form was maintained even after 8 hours, In the second and third methods, 100% conversion to the β-type crystal form occurred after about 4 hours. As described above, regarding each of these α-H ₂ Pcs, the method described in Japanese Patent Publication No. 45-8102 is not found to be effective, and the third method does not produce methyl ethyl ketone even if α-H ₂ Pc is of high purity. In the presence of , milling for longer periods of time is futile. Comparative Example 3 According to Example 1, crude β-H ₂ Pc was obtained. 20 g of this crude β-H ₂ Pc was charged into a Pyrex tube with an inner diameter of 25 mm and a length of 400 mm L sealed at one end, and heated to 550° C. under a reduced pressure of 0.1 mmHg to perform sublimation purification. The obtained β-H ₂ Pc was further sublimated twice in the same manner to obtain 10 g of β-H ₂ Pc as a sublimation purified product (purity 98.5%). This β-H ₂ Pc was milled under the same conditions as in Example 1, and after 256 hours _, 100
% converted. However, as shown in the reference example, this x
The photoconductive properties of -H ₂ Pc are based on the x-
It was far inferior to H ₂ Pc. i.e. H ₂ Pc
Even if the purity is sufficiently high, the effects of the present invention will not be achieved if the purification process is different. Comparative Example 4 Pigment α-H ₂ Pc (BASF, Heliogen blne
L7560) 200g, diglyme 2000g and 62% potassium hydroxide aqueous solution 1000g using a stirrer, dropping funnel,
The mixture was placed in a No. 5 four-necked flask equipped with a thermometer, a nitrogen gas inlet tube, and a ball filter, and reacted for 30 minutes at 80° C. in a nitrogen gas atmosphere. After the reaction was completed, the mixture was allowed to stand at a temperature of 80° C. for 30 minutes to separate the diglyme layer and the aqueous layer. At this time, an unreactive blue substance had gathered at the interface. Next, the diglyme layer was suctioned through a ball filter and a glass filter. Since an unreacted blue substance was suspended in the diglyme, this filter was used in Example 1.
It was more difficult than before. The liquid was immediately introduced into 500 g of 5% aqueous hydrochloric acid solution, and under strong stirring, K ₂ Pc
(diglyme) ₂ was decomposed. The resulting blue slurry was filtered, washed with warm water until the liquid became neutral, and then diluted with acetone 3
By washing with water and drying under reduced pressure under heat, 172.2 g of blue fine powder was obtained (yield: 86.1%). Furthermore, using this entire amount, the above operation was performed again to obtain 155.3 g of purified α-H ₂ Pc (yield: 90.2
%). The purity was 96.7%. This purified α-H ₂ Pc20.0g was
Pour into an alumina ball mill with an internal volume of 400ml.
After adding 400g of alumina balls with an outer diameter of 10mmφ,
Milling was carried out at room temperature for 100 hours at a rotation speed of 100 rpm. The X-ray diffraction and infrared absorption spectrum of the contents were consistent with α-H ₂ Pc, and almost no x-H ₂ Pc was produced. Example 3 Into 10 four-necked flasks equipped with a stirrer, thermometer, nitrogen gas inlet tube, and reflux condenser, 512.6 g of phthalonitrile, 8 g of 2-methoxyethanol, and
608.6 g of DBU was charged and maintained at reflux temperature for 24 hours under nitrogen atmosphere. After cooling to room temperature, the mixture was separated to obtain reddish-purple crystals. The product was washed with 1 part of 2-methoxyethanol, 4 parts of water, and 1 part of acetone, and dried to obtain 228.5 g of β-H ₂ Pc. Purity is 93.1
It was %. 400 g of anhydrous ethanol and 1.2 g of metallic lithium were added to a four-necked flask equipped with a stirrer, a thermometer, a nitrogen gas inlet tube, and a reflux condenser, and the lithium was dissolved at room temperature under a nitrogen atmosphere. Next, 40 g of the above crude β-H ₂ Pc was added and reacted under reflux for 30 minutes.
As the reaction progressed, the system turned green and became a homogeneous solution. After the reaction, the solution was suctioned through a ball filter and a glass filter, and the resulting solution was immediately introduced into 130 g of a 5% aqueous hydrochloric acid solution, under strong stirring.
The decomposition of Li ₂ Pc was carried out. The resulting blue slurry was separated and washed with warm water until it became neutral, and then diluted with acetone 200
ml and dried under reduced pressure under heat to obtain 36.3 g of blue fine powder. Further, the above purification was performed again using this entire amount, and 35.4 g of α-H ₂ Pc was obtained (yield: 88.5%).
The purity was 98.5%. 20.0 g of this high-purity α-H ₂ Pc was placed in an alumina ball mill with an outer diameter of 90 mmφ and an internal volume of 400 ml (containing 400 g of 10 mmφ alumina balls), and heated at room temperature.
Milling was carried out for 100 hours at a rotation speed of 100 rpm.
The X-ray diffraction and infrared absorption spectrum of the contents are as follows:
Consistent with x-H ₂ Pc. Example 4 400 g of dried diglyme, 40 g of crude β-H ₂ Pc obtained in Example 3 and
After adding 19.2 g of tert-butoxypotassium and stirring at room temperature under nitrogen atmosphere for 30 minutes, the internal temperature was raised to 80° C. over 1 hour and maintained at that temperature for 30 minutes. The contents were then suctioned through a ball filter and a glass filter, and the liquid was directly introduced into No. 2 four-necked flask (equipped with a stirrer, dropping funnel, and nitrogen gas introduction tube). After heating, under strong stirring,
700 g of 1% hydrochloric acid was added from the dropping funnel over a period of 1 hour to decompose K ₂ Pc (diglyme) ₂ . The resulting blue slurry was filtered, washed with warm water until the liquid became neutral, then washed with 500 ml of acetone, and dried under reduced pressure with heat.
34.1 g of H ₂ Pc was obtained (yield 85.2%). Furthermore, the above purification was carried out again using this whole amount, and 31.1 g of α-H ₂ Pc (purity 98.2%) was obtained. 20.0 g of this high purity α-H ₂ Pc was milled in the same manner as in Example 3 to obtain x-H ₂ Pc. Reference Example 1 (Optoelectronic Properties) As a reference example, photoconductivity of x-H ₂ Pc obtained in Examples and Comparative Examples to demonstrate electrostatic recording paper and test equipment (manufactured by Kawaguchi Electric Co., Ltd., SP-428) An example of measuring the attenuation of surface potential using the characteristics is shown below. Of course, this example should not be construed to limit the field of application of the present invention to electrophotography. The evaluation was performed by corona charging to 6KV (the potential at this time was taken as the initial potential V ₀ (V)),
Leave it in the dark for 10 seconds (the surface potential at this time is V ₁₀
(expressed as V), the time (seconds) it takes for V ₁₀ to become 1/2 when irradiated with 51ux light from a tungsten lamp.
The product of
sec)). In addition, for the sample, H ₂ Pc was dispersed in a polymer binder (Toyobo Byron 200) (H ₂ Pc/polymer = 15/85), coated with a bar coater on a plate with aluminum vapor-deposited on the resin, and dried. I made adjustments by doing this. The results are shown in Table 1. From Table 1, it is clear that the x-H ₂ Pc obtained by the method of the invention exhibits stable and excellent electrophotographic properties. 【table】

[Brief explanation of drawings]

The drawing represents the X-ray diffraction pattern of x-H ₂ Pc (using copper Kα radiation), and FIG.
It is an X-ray diffraction diagram described in specification No. 3357989,
Figure 2 shows x obtained in Examples 1 and 3 of the present invention.
-H ₂ Pc is an X-ray diffraction diagram.

Claims (1)

[Scope of Claims] 1. Phthalonitrile is reacted in the presence of a strong base to produce metal-free phthalocyanine, the resulting crude product is subjected to solvent solubilization treatment, and the resulting solubilized product is treated with a solvent. A highly pure metal-free phthalocyanine is obtained by purification treatment and restoration treatment of the obtained purified solubilized material, and then the original crystal structure is converted to the x-type by ball milling. A method for producing high purity x-type metal-free phthalocyanine. 2 The strong base is 1,8-diazabicyclo[5.4.0]
Claim 1 which is undecene-7 or 1,5-diazabicyclo[4.3.0]nonene-5
The method described in section. 3. Claim 1 or 2, wherein the solvent solubilization treatment is converting metal-free phthalocyanine into dilithium phthalocyanine, or converting metal-free phthalocyanine into dipotassium phthalocyanine and then forming a complex with the solvent. The method described in section. 4 Claims 1, 2, or 3, wherein the purification treatment is separation of solvent-insoluble substances and/or precipitation separation of impurity components or components to be purified from a solution.
The method described in section.