PR207 intermediate preparation method and PR207 pigment

Abstract

The invention discloses a preparation method of a PR207 intermediate and a PR207 pigment, and the preparation method of the PR207 intermediate comprises the following steps: S1, condensation: condensing DMSS, aniline and o-chloroaniline, fully mixing the condensed DMSS, aniline and o-chloroaniline with inorganic acid in an alcoholic solution, and carrying out condensation reaction in a reflux or distillation state to obtain a condensed solution; the method comprises the following steps: S1, condensing a condensed solution, S2, oxidizing, adding an alkali metal hydroxide into the condensed solution, and adding a hydrogen peroxide mixed solution in a reflux state for oxidation, S3, diluting a reaction solution obtained in S2 with water, and filtering to obtain a catalyst and a filtrate, and the step S2 further comprises the following steps: S21, adding 40-60% of the alkali metal hydroxide and the catalyst into the condensed solution, preparing other alkali metal hydroxides into an alkali metal hydroxide solution; s22, slowly raising the temperature to reflux; s23, dropwise adding a 40%-60% hydrogen peroxide mixed solution; and S24, dropwise adding the alkali metal hydroxide solution from the return pipe, and fully stirring after the alkali metal hydroxide solution and the hydrogen peroxide mixed solution are dropwise added.

Description

Technical Field

[0001] The invention relates to the field of pigment production, in particular to a method for preparing a PR207 intermediate. Background Art

[0002] PR 207 - Quinacridone Scarlet Red, in the prior art, is prepared by condensation, ring closure, and oxidation of o-chloroaniline with aniline and methyl succinosuccinate (DMSS). During the oxidation process, an alkali metal hydroxide such as potassium hydroxide or sodium hydroxide is added at once. Due to the electron-withdrawing effect of chloride ions, the yield and purity of PR207 are low, as shown in Chinese Patent Publication No. CN114751837 A.

[0003] The yield is usually about 87% and the purity is about 93%. Side reactions are more likely to occur when the hydroxide concentration is high or low, and the oxidation reaction is incomplete when the hydroxide concentration is low.

[0004] The electron-withdrawing effect of chloride ions can be explained from their physical and chemical properties. Chlorine has a larger atomic radius than carbon atoms, which means that its conjugation effect is weaker, but its electronegativity is very strong and its inductive effect is large. On the whole, the inductive effect is greater than the conjugation effect, causing chloride ions to behave as electron-withdrawing groups in organic chemistry. In addition, from the measurement of the substituent constant in the Hammett equation, it can be seen that although chlorine is a weak electron-withdrawing group, its electron-withdrawing ability is even worse than that of bromine and iodine, but it still exhibits an electron-withdrawing effect. The electron-withdrawing effect of chloride ions is particularly evident when they interact with benzene rings. When chlorine atoms replace hydrogen atoms on the benzene ring, the electron cloud of the benzene ring will transfer to the more electronegative chlorine atom, resulting in a decrease in the overall electron cloud density of the benzene ring. This decrease makes the aromatic electrophilic substitution reaction of chlorobenzene slower than that of benzene, because the speed of the reaction depends on the electron cloud density of the benzene ring. Although chloride ions exhibit electron-withdrawing effects, they are also ortho-para directing groups because the presence of chloride ions makes the ortho-para positions have higher electron cloud densities than the meta positions, making it easier for electrophilic reagents to attack the carbon atoms at these two positions. Summary of the invention

[0005] In order to solve the above problems, the object of the present invention is to provide a method for preparing a PR207 intermediate and a PR207 pigment with good yield and purity.

[0006] In order to achieve the above effects, the present invention provides a method for preparing a PR207 intermediate, comprising: S1, condensation, condensing DMSS, aniline and o-chloroaniline and fully mixing the inorganic acid in an alcohol solution, and performing a condensation reaction under reflux or distillation to obtain a condensation solution; S2, oxidation, adding an alkali metal hydroxide to the condensation solution, adding a hydrogen peroxide mixed solution under reflux to perform oxidation, S3, diluting the reaction solution obtained in S2 with water, filtering to obtain a catalyst and a filtrate, then adding water to dilute the filtrate, adding acid to the filtrate for acidification, filtering, washing, and drying to obtain PR 207 intermediate, further comprising: the step S2 comprises: S21, adding 40%-60% alkali metal hydroxide and a catalyst to the condensation solution, and preparing the remaining alkali metal hydroxide into an alkali metal hydroxide solution; S22, slowly heating to reflux; S23, dripping 40%-60% hydrogen peroxide mixture; S24, dripping alkali metal hydroxide solution, alkali metal hydroxide solution, hydrogen peroxide mixture dripping is completed, and stirring is sufficient.

[0007] In one embodiment of the present invention, the alcohol solution comprises: methanol and ethanol in a volume ratio of 1:9.

[0008] In one embodiment of the present invention, the hydrogen peroxide mixture comprises 40-60 parts by weight of hydrogen peroxide and 15-20 parts by weight of ethanol.

[0009] In one embodiment of the present invention, the alkali metal hydroxide is selected from potassium hydroxide or sodium hydroxide.

[0010] In one embodiment of the present invention, the catalyst is selected from one of anthraquinone oxide, 2,2,6,6-tetramethylpiperidine or 2,2,6,6-tetramethylpiperidinyl oxide.

[0011] In one embodiment of the present invention, the weight ratio of oxidized anthraquinone to dimethyl succinylsuccinate is 3%-8%:1; and / or the weight ratio of 2,2,6,6-tetramethylpiperidine or 2,2,6,6-tetramethylpiperidinoxide to dimethyl succinylsuccinate is 3%-8%:1.

[0012] In one embodiment of the present invention, the step S24 comprises dripping an alkali metal hydroxide solution from a reflux pipe.

[0013] In one embodiment of the present invention, step S21 comprises: adding 45%-55% of alkali metal hydroxide and a catalyst to the condensation solution, and preparing the remaining alkali metal hydroxide into an alkali metal hydroxide solution.

[0014] In one embodiment of the present invention, step S21 comprises: adding 50% alkali metal hydroxide and a catalyst to the condensation solution, and preparing the remaining alkali metal hydroxide into an alkali metal hydroxide solution.

[0015] The present invention also provides a PR207 pigment, which is obtained by adding a polyacid to any of the above PR207 intermediates for ring closing, and then boiling with alkali to remove impurities and convert the pigment into a pigment.

[0016] In this application, ① First add part of the alkali metal hydroxide to the condensation solution, and then add the alkali metal hydroxide solution dropwise after the partial oxidation reaction. As the hydrolysis and oxidation reaction proceeds, the concentration of the alkali continues to decrease, and potassium hydroxide is added dropwise to maintain the concentration of the alkali and reduce side reactions. The hydroxide concentration in the oxidation reaction is more appropriate, so the electron-withdrawing effect of the chloride ion is suppressed, the yield is 92-93%, and the purity is 98%.

[0017] ② Using a mixture of methanol and ethanol, the hydrophilic and lipophilic balance helps to quickly dissolve DMSS, o-chloroaniline, aniline, concentrated sulfuric acid, water, potassium hydroxide, hydrogen peroxide, and anthraquinone, thereby increasing the reaction rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a reaction raw material diagram of the present invention.

[0019] Figure 2 It is a liquid chromatogram of the first embodiment of the present invention.

[0020] Figure 3 It is a liquid chromatogram of the fourth embodiment of the present invention. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only some embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] See also Figure 1-3 In this application, the yield is calculated by weighing, and the yield = the (actual) amount of the target product produced / the theoretical amount of the target product produced × 100%.

[0023] 1 The purity was determined by liquid chromatography area normalization method.

[0024] 1.1 Instrument conditions Chromatographic column: XBP-C18 or equivalent type of chromatographic column; Detector: Liquid chromatograph Shimadzu LC-20A.

[0025] 1.2 Reagents and Solutions Acetonitrile: chromatographic grade; Water: distilled water; Tetrahydrofuran: analytical grade; Phosphoric acid: analytical grade; Mobile phase: acetonitrile: water = 60:40 (V / V), adjust the pH to 3.0 with phosphoric acid, and remove bubbles before use.

[0026] 1.3 Test conditions Pump flow rate: 0.8ml / min; Wavelength: 325nm.

[0027] 1.4 Detection steps Weigh about 0.03 g of the intermediate sample into a 50 ml volumetric flask, make up to volume with tetrahydrofuran, and dissolve by ultrasonication.

[0028] After the baseline is stable, the sample is injected and the workstation (liquid chromatograph Shimadzu LC-20A) is turned on at the same time. The workstation performs automatic analysis and calculations to obtain the area normalized content (that is, purity) of the sample. Ratio Alcohol mixture (methanol 10% ethanol 90%) 250g + 104g DMSS 80g Aniline 48g 44 g o-chloroaniline 60% sulfuric acid 6 g Anthraquinone 6.4 g Potassium hydroxide 67 g 46g hydrogen peroxide mixture + 17.0g alcohol Dilution water 1120 g Example 1

[0029] S1. Condensation: Add 250 g of alcohol mixture to a 1L three-necked flask, start stirring, add DMSS, o-chloroaniline, aniline, and concentrated sulfuric acid in sequence, slowly heat up to reflux, maintain strong reflux for 5 hours, cool down to 55°C, and simultaneously add 104 g of alcohol mixture to rinse the inner wall of the container to obtain a condensation solution.

[0030] S2, oxidation: S21, adding 35 grams of potassium hydroxide and anthraquinone to the condensation solution, and preparing the remaining potassium hydroxide into a potassium hydroxide solution with a molar concentration of 50% with water; S22, slowly raise the temperature to strong reflux of ethanol; S23, add 50% hydrogen peroxide mixture dropwise, and soak for about 40 minutes; S24. Add 50% potassium hydroxide solution (32 g potassium hydroxide + 28.26 g water) and hydrogen peroxide mixture dropwise from the reflux tube and stir for 10 minutes.

[0031] S3 dilution: Add 1120 g of water at 60-65°C into a 3L beaker, start stirring, add the liquid into the beaker, and stir at 60-65°C for 30 minutes.

[0032] S4 acid precipitation: add recycled phosphoric acid dropwise, control the end point pH to 4-4.5, stir at 60-65℃ for 30 minutes. Filter, wash with water, and dry to obtain PR207 intermediate. The purity is 98.005% and the yield is 93.231% Comparative Example The difference from Example 1 is that 67 g of potassium hydroxide and anthraquinone are added at one time in step 21, and the purity of the final PR207 intermediate is 92.204%, and the yield is 87.113%. Example 2

[0033] The difference from Example 1 is that step 21 is to add 25 g of potassium hydroxide and anthraquinone to the condensation solution, and step 23 is to dropwise add a 40% hydrogen peroxide mixture for about 32 minutes; the final purity of the PR207 intermediate is 97.634%, and the yield is 92.673%. Example 3

[0034] The difference from Example 1 is that step 21 is to add 45 g of potassium hydroxide and anthraquinone to the condensation solution; step 23 is to dropwise add a 60% hydrogen peroxide mixture for about 32 minutes; the final purity of the PR207 intermediate is 97.127%, and the yield is 91.328%. Example 4

[0035] The difference from Example 1 is that in step 24, 50% potassium hydroxide solution is added dropwise from the reflux tube; the final purity of the PR207 intermediate is 98.041%, and the yield is 93.036%. Example 5

[0036] The PR207 intermediate is subjected to ring closure by adding a polyacid, alkali boiling to remove impurities and then pigmentation to obtain the PR207 pigment.

[0037] In this application, ① First add part of the alkali metal hydroxide to the condensation solution, and then add the alkali metal hydroxide solution dropwise after the partial oxidation reaction. As the hydrolysis and oxidation reaction proceeds, the concentration of the alkali continues to decrease, and potassium hydroxide is added dropwise to maintain the concentration of the alkali and reduce side reactions. The hydroxide concentration in the oxidation reaction is more appropriate, so the electron-withdrawing effect of the chloride ion is suppressed, the yield is 92-93%, and the purity is 98%.

[0038] ② Using a mixture of methanol and ethanol, the hydrophilic and lipophilic balance helps to quickly dissolve DMSS, o-chloroaniline, aniline, concentrated sulfuric acid, water, potassium hydroxide, hydrogen peroxide, and anthraquinone, thereby increasing the reaction rate.

Claims

1. A method for preparing a PR207 intermediate, comprising: S1, condensation, condensing DMSS, aniline and o-chloroaniline and fully mixing the inorganic acid in an alcohol solution, and performing a condensation reaction under reflux or distillation to obtain a condensation solution; S2, oxidation, adding an alkali metal hydroxide to the condensation solution, adding a hydrogen peroxide mixture under reflux to oxidize, S3, diluting the reaction solution obtained in S2 with water, filtering to obtain a catalyst and a filtrate, then adding water to dilute the filtrate, adding acid to the filtrate for acidification, filtering, washing, and drying to obtain a PR 207 intermediate, characterized in that it also includes: the step S2 includes: S21, adding 40%-60% of alkali metal hydroxide and a catalyst to the condensation solution, and preparing an alkali metal hydroxide solution with the remaining alkali metal hydroxide; S22, slowly raise the temperature to reflux; S23, adding 40%-60% hydrogen peroxide mixture; S24, dropwise adding alkali metal hydroxide solution, after the alkali metal hydroxide solution and hydrogen peroxide mixture are added, stirring is thorough.

2. The method for preparing the PR207 intermediate according to claim 1, characterized in that: The alcohol solution comprises methanol and ethanol in a volume ratio of 1:

9.

3. The method for preparing the PR207 intermediate according to claim 1, characterized in that: The hydrogen peroxide mixed liquid comprises 40-60 parts by weight of hydrogen peroxide and 15-20 parts by weight of ethanol.

4. The method for preparing the PR207 intermediate according to claim 1, characterized in that: The alkali metal hydroxide is selected from potassium hydroxide or sodium hydroxide.

5. The method for preparing the PR207 intermediate according to claim 1, characterized in that: The catalyst is selected from one of anthraquinone oxide, 2,2,6,6-tetramethylpiperidine or 2,2,6,6-tetramethylpiperidinyl oxide.

6. The method for preparing the PR207 intermediate according to claim 1, characterized in that: The weight ratio of oxidized anthraquinone to dimethyl succinylsuccinate is 3%-8%:1; and / or the weight ratio of 2,2,6,6-tetramethylpiperidine or 2,2,6,6-tetramethylpiperidinoxide to dimethyl succinylsuccinate is 3%-8%:

1.

7. The method for preparing the PR207 intermediate according to claim 1, characterized in that: The step S24 includes dripping an alkali metal hydroxide solution from a reflux pipe.

8. The method for preparing the PR207 intermediate according to claim 1, characterized in that: The step S21 comprises: adding 45%-55% of alkali metal hydroxide and a catalyst to the condensation solution, and preparing the remaining alkali metal hydroxide into an alkali metal hydroxide solution.

9. The method for preparing the PR207 intermediate according to claim 1, characterized in that: The step S21 comprises: adding 50% of alkali metal hydroxide and a catalyst to the condensation solution, and preparing the remaining alkali metal hydroxide into an alkali metal hydroxide solution.

10. A PR207 pigment, characterized in that The PR207 intermediate described in any one of claims 1 to 9 is added with polyacid to close the ring, and then boiled with alkali to remove impurities and pigmentate the obtained product.

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