CN103193740A - Preparation method of alpha-naphtholphthalein - Google Patents

Abstract

A preparation method of α-naphtholphthalein, which comprises a. crushing process: phthalic anhydride and 1-naphthol are pulverized into powder in advance; b. reaction process; c. separation and purification process: dissolve the above viscose with solvent a thick reactant, filter; neutralize the filtrate with alkaline solution, filter, concentrate the filtrate to obtain a viscous liquid; add solvent b to the viscous liquid, heat to boiling, cool down and filter; add deionized water to the filter cake, heat until boiling, filtering, washing, dissolving the filter cake with solvent c, heating to boiling and strong analysis with deionized water, filtering; drying to obtain α-naphtholphthalein powder. The invention has simple process, high product yield and high purity, and is easy for industrialized production.

Description

The preparation method of α-naphtholphthalein

technical field

The invention relates to a preparation method of α-naphtholphthalein.

technical background

α-naphtholphthalein is also known as 1-naphtholphthalein, methyl-naphtholphthalein, 3,3'-bis(4-hydroxy-1-naphthyl)-1(3H)-isobenzofuranone, English name: α-Naphtholphthalein , 3,3-Bis(4-hydroxy-1-naphthyl)phthalide

The structural formula is as follows:

Its reaction principle is as follows:

The disclosed preparation method is: 3.8 grams of phthalic anhydride and 7.0 grams of α-naphthol were reacted at 60° C. using 0.75 ml of concentrated sulfuric acid as a catalyst for 4 hours to obtain a viscous crude product. The sulfuric acid was diluted with a large amount of water and crushed to make the product into a Granular, then heated to 70°C with a large amount of 0.5% dilute alkali (NaOH) to dissolve the product, filter and separate the by-products, then adjust the pH with hydrochloric acid to precipitate the product α-naphtholphthalein, set aside to precipitate, filter and wash, and repeat alkali dissolution and acid analysis once. Vacuum drying over sulfuric acid yielded 2.3 g of product. The preparation method has the following disadvantages: (1) the yield of the product is low; (2) the purity of the product is low; (3) the production cost is high, and large-scale industrial production cannot be carried out.

Contents of the invention

The technical problem to be solved by the present invention is to provide a preparation method of α-naphtholphthalein aiming at the deficiencies of the prior art.

In order to solve the problems of the technologies described above, the technical solution adopted in the present invention is:

A preparation method of α-naphtholphthalein, said method comprising the following steps:

a. Pulverization process: phthalic anhydride and 1-naphthol are pulverized into powder in advance;

b. Reaction process:

Add the above-mentioned phthalic anhydride and 1-naphthol crushed into powder in the reaction vessel, the molar ratio is 1:1.5～1:2.5; add the catalyst under stirring, and react at the temperature of 0～40°C for more than 3h, Let it stand still for more than 12 hours, then stir and react at 35-60°C for more than 3 hours, take a sample and track it with liquid chromatography, stop the reaction when the content of the main product of the reaction no longer increases, and obtain a viscous reactant;

c. Separation and purification process:

Dissolve the above viscous reactants with solvent a, filter; neutralize the filtrate with alkali solution, filter, cool down to precipitate, filter; concentrate the filtrate to obtain a viscous liquid; add solvent b to the viscous liquid, heat to boiling, cool down and filter ; transfer the filter cake to a container, add deionized water, heat to boiling, filter, and wash; transfer the filter cake to a container and dissolve it with solvent c, heat to boiling and use deionized water for strong analysis, filter; dry to obtain α- Naphtholphthalein powder.

In the above preparation method, the molar ratio of phthalic anhydride to 1-naphthol is 1:1.8 to 1:2.2.

In the above preparation method, the catalyst is a Lewis acid, preferably ZnCl ₂ , AlCl ₃ , TiCl ₄ , concentrated sulfuric acid or methanesulfonic acid, more preferably concentrated sulfuric acid or methanesulfonic acid.

In the above preparation method, the solvent a is ethanol, methanol or ether, benzene; the solvent b is chloroform, acetone or butanone; the solvent c is ethanol or methanol.

In the above preparation method, in the b. reaction step, after adding the catalyst, react at a temperature of 10-15°C for more than 3 hours, stand still for more than 12 hours, and then react with stirring at 35-45°C for more than 3 hours.

In the above preparation method, in the b. reaction step, after adding the catalyst, react at a temperature of 10-15°C for 72h, let stand for more than 12h, and then react with stirring at 35-45°C for 10-24h.

Beneficial effect

Compared with prior art, the present invention has following advantage:

1. By pulverizing the raw materials naphthol and phthalic anhydride, the contact area of the reactants can be greatly increased, the reaction rate can be increased, and it is easy to purify after treatment.

2. In the reaction process, the use of step-by-step temperature and matching reaction time can take into account the reaction conversion rate and reaction rate, so that the yield is higher and the by-products are relatively low; the use of a preferred catalyst can obtain a reaction product that is easy to post-process, especially It is suitable for industrialized unit operation.

3. adopt technology of the present invention, reaction product is not hard agglomerate, but viscous shape, and then can add solvent a to dissolve and separate with main by-product, be suitable for industrialized unit operation; Solvent of the present invention all can reclaim and repeat Utilization can reduce environmental pollution and cost; it can greatly reduce the volume of alkali solution during post-treatment (concentration increased by 40 times), which is suitable for industrial unit operation; the amount of waste water is small; the separation and purification are thorough, and products with a content of more than 98% can be easily obtained; High rate.

Description of drawings

Accompanying drawing 1 is the infrared spectrogram of embodiment 1 product.

Accompanying drawing 2 is the nuclear magnetic resonance spectrogram of embodiment 1 product.

Detailed ways

Comparative example:

Stirring was installed in a 1L three-necked flask (stirring speed: 500 rpm). Phthalic anhydride 190g, α-naphthol 350g, feed ratio (mol ratio) is 1:1.89, stir evenly, add concentrated sulfuric acid 37.5ml, keep temperature at 60°C for 4h, get very viscous crude product, break the there-necked bottle, Dilute the sulfuric acid product with 50L of water and crush the product into granules. Soak the granulated product with 50L of water for several times and wash until the washing water is neutral, then heat to 70℃ with 100L of 0.5% dilute alkali (NaOH) to dissolve the product, filter and separate For by-products, cool the filtrate to below 10°C, slowly add 1:1 (V/V) hydrochloric acid dropwise to adjust the pH to precipitate the product α-naphtholphthalein, let stand overnight to precipitate, filter and wash, and repeat alkali dissolution and acid analysis once, Filtration, vacuum drying through sulfuric acid to obtain 85.5 grams of product, the content determined by liquid chromatography is 93.45%.

Example 1:

a. Pulverization process: phthalic anhydride and α-naphthol are pulverized into powder in advance;

b. Reaction process:

In a 1L three-neck flask equipped with stirring (stirring speed 225rpm), add 190g of phthalic anhydride powder and 350g of α-naphthol powder, the ratio (mol ratio) is 1:1.89, stir evenly and add 150ml of methanesulfonic acid, React at 15°C for 9 hours, and place it at 10-15°C for 62 hours, then raise the temperature to 40°C, keep stirring for 9 hours, and take a sample to measure the color content of the liquid to be 28.85%;

c. Separation and purification process:

Dissolve the dark green viscous reactant with 4.6L of absolute ethanol, white insoluble matter precipitates out, filter, at this time the filtrate is strongly acidic, adjust with 437ml of 20% (w/w) NaOH (deionized water configuration) The pH value is neutral (tested with test paper), and a large amount of insoluble matter precipitates out, which is slightly viscous. After filtering, the filtrate cools down and insoluble matter precipitates out. Filter again, and rinse the filter cake with a small amount of absolute ethanol. All filtrates were distilled under reduced pressure until no liquid dripped down to recover ethanol. After vacuum distillation, add 2L of chloroform to the viscous liquid in the bottle, heat to boiling, then insoluble matter precipitates out, filter, and wash the filter cake with 1L of chloroform, and the filtrate is distilled under reduced pressure to recover chloroform. The filter cake was washed with 3L of deionized water, transferred to a container and heated to boiling, boiled, filtered, and the filter cake was washed with hot deionized water until the pH of the filtrate was neutral. Dissolve the filter cake with 2L of absolute ethanol, heat it to boiling (completely dissolved), analyze it strongly with 2.25L of distilled water, a light pink solid precipitates out, filter it, and dry the filter cake in an electric drying oven at 35°C to obtain a light pink color The powdery product was 152.1 g, and the yield was 30.05%. The content determined by liquid chromatography is 99.28%.

Example 2:

a. Pulverization process: phthalic anhydride and α-naphthol are pulverized into powder in advance;

b. Reaction process:

In a 1L three-neck flask equipped with stirring (stirring speed 225rpm), add 190g of phthalic anhydride powder and 370g of α-naphthol powder, the ratio of feed (mol ratio) is 1:2.0, stir evenly and add 150ml of methanesulfonic acid, React at 10°C for 15h, and stand at 10-15°C for 60h, then raise the temperature to 40°C, keep stirring for 9h, stand at room temperature for 14h, and room temperature to 40°C. Sampling and measuring liquid color content is 29.31%.

c. Separation and purification process:

Dissolve the dark green viscous reactant with 4.6L of absolute ethanol, and white insoluble matter precipitates out, and filter it. At this time, the filtrate is strongly acidic, adjust it with 430ml of 20% (w/w) NaOH (deionized water configuration) The pH value is neutral (tested with test paper), and a large amount of insoluble matter precipitates out, which is slightly viscous. After filtering, the filtrate cools down and insoluble matter precipitates out. Filter again, and rinse the filter cake with a small amount of absolute ethanol. All filtrates were distilled under reduced pressure until no liquid dripped down to recover ethanol. After vacuum distillation, add 2L of chloroform to the viscous liquid in the bottle, heat to boiling, then insoluble matter precipitates out, filter, and wash the filter cake with 1L of chloroform, and the filtrate is distilled under reduced pressure to recover chloroform. The filter cake was washed with 3L of deionized water, transferred to a container and heated to boiling, boiled, filtered, and the filter cake was washed with hot deionized water until the pH of the filtrate was neutral. Dissolve the filter cake with 2L of absolute ethanol, heat it to boiling (completely dissolved), analyze it strongly with 2.25L of distilled water, a light pink solid precipitates out, filter it, and dry the filter cake in an electric drying oven at 35°C to obtain a light pink color The powdery product was 154.3 g, and the yield was 30.48%. The content determined by liquid chromatography is 99.42%.

Example 3:

a. Pulverization process: phthalic anhydride and α-naphthol are pulverized into powder in advance;

b. Reaction process:

Add 190g of phthalic anhydride powder and 334g of α-naphthol powder into a 1L three-neck flask with stirring (stirring speed 225rpm), and the ratio (mol ratio) is 1:1.8. Stir evenly and add 180ml of methanesulfonic acid , reacted at 15°C for 9h, and stood at 25°C for 38h, then raised the temperature to 40°C, reacted for 9h under stirring, and took a sample to measure the liquid color content to be 27.63%.

c. Separation and purification process:

Use 4.6L of absolute ethanol to dissolve the dark green viscous reactant, white insoluble matter precipitates out, filter, at this time the filtrate is strongly acidic, adjust with 460ml of 20% (w/w) NaOH (deionized water configuration) The pH value is neutral (tested with test paper), and a large amount of insoluble matter precipitates out, which is slightly viscous. After filtering, the filtrate cools down and insoluble matter precipitates out. Filter again, and rinse the filter cake with a small amount of absolute ethanol. All filtrates were distilled under reduced pressure until no liquid dripped down to recover ethanol. After vacuum distillation, add 2L of chloroform to the viscous liquid in the bottle, heat to boiling, then insoluble matter precipitates out, filter, and wash the filter cake with 1L of chloroform, and the filtrate is distilled under reduced pressure to recover chloroform. The filter cake was washed with 3L of deionized water, transferred to a container and heated to boiling, boiled, filtered, and the filter cake was washed with hot deionized water until the pH of the filtrate was neutral. Dissolve the filter cake with 2L of absolute ethanol, heat it to boiling (completely dissolved), analyze it strongly with 2.25L of distilled water, a light pink solid precipitates out, filter it, and dry the filter cake in an electric drying oven at 35°C to obtain a light pink color The powdery product was 146.1 g, and the yield was 28.86%. The content determined by liquid chromatography is 99.07%.

Example 4:

a. Pulverization process: phthalic anhydride and α-naphthol are pulverized into powder in advance;

b. Reaction process:

Add 190g of phthalic anhydride powder and 389g of α-naphthol powder into a 1L three-neck flask with stirring (stirring speed 225rpm), and the ratio (mol ratio) is 1:2.1. Stir evenly and add 150ml of methanesulfonic acid , reacted at 15°C for 9h, and placed at 10-15°C for 62h, then raised the temperature to 40°C, reacted for 9h under stirring, and the liquid color content was 28.18% by sampling.

c. Separation and purification process:

Use 5.9L of methanol to dissolve the dark green viscous reactant, white insoluble matter precipitates out, filter, the filtrate is strongly acidic at this time, adjust the pH value with 437ml of 20% (w/w) NaOH (deionized water configuration) It is neutral (tested with test paper), a large amount of insoluble matter precipitates, slightly viscous, filter, the filtrate cools down and insoluble matter precipitates out, filter again, and rinse the filter cake with a small amount of methanol. All filtrates were distilled under reduced pressure until no liquid dripped, and methanol was recovered. After vacuum distillation, add 2L of chloroform to the viscous liquid in the bottle, heat to boiling, then insoluble matter precipitates out, filter, and wash the filter cake with 1L of chloroform, and the filtrate is distilled under reduced pressure to recover chloroform. The filter cake was washed with 3L of deionized water, transferred to a container and heated to boiling, boiled, filtered, and the filter cake was washed with hot deionized water until the pH of the filtrate was neutral. Dissolve the filter cake in 2.3L of methanol, heat it to boiling (dissolve completely), analyze it strongly with 2.8L of distilled water, a light pink solid precipitates, filter it, and dry the filter cake in an electric drying oven at 35°C to obtain a light pink powder The product was 142.3 g, and the yield was 28.11%. The content determined by liquid chromatography was 98.42%.

Example 5:

a. Pulverization process: phthalic anhydride and α-naphthol are pulverized into powder in advance;

b. Reaction process:

Add 190g of phthalic anhydride powder and 350g of α-naphthol powder into a 1L three-necked flask with stirring (stirring speed 225rpm), and the ratio of feed (mol ratio) is 1:1.89. Stir evenly and add 150ml of methanesulfonic acid , reacted at 15°C for 9h, and placed at 10-15°C for 62h, then raised the temperature to 40°C, reacted for 9h under stirring, and the liquid color content was 29.32% by sampling.

c. Separation and purification process:

Dissolve the dark green viscous reactant with 4.6L of absolute ethanol, white insoluble matter precipitates out, filter, at this time the filtrate is strongly acidic, adjust with 437ml of 20% (w/w) NaOH (deionized water configuration) The pH value is neutral (tested with test paper), and a large amount of insoluble matter precipitates out, which is slightly viscous. After filtering, the filtrate cools down and insoluble matter precipitates out. Filter again, and rinse the filter cake with a small amount of absolute ethanol. All filtrates were distilled under reduced pressure until no liquid dripped down to recover ethanol. Add 3.5L of acetone to the viscous liquid in the bottle after vacuum distillation, heat to boiling, then insoluble matter is precipitated, filter, the filter cake is washed with 1.2L of acetone, and the filtrate is distilled under reduced pressure to recover acetone. The filter cake was washed with 3L of deionized water, transferred to a container and heated to boiling, boiled, filtered, and the filter cake was washed with hot deionized water until the pH of the filtrate was neutral. Dissolve the filter cake with 2L of absolute ethanol, heat it to boiling (completely dissolved), analyze it strongly with 2.25L of distilled water, a light pink solid precipitates out, filter it, and dry the filter cake in an electric drying oven at 35°C to obtain a light pink color The powdery product was 148.8 g, and the yield was 29.40%. The content determined by liquid chromatography is 98.87%.

Embodiment 6:

a. Pulverization process: phthalic anhydride and α-naphthol are pulverized into powder in advance;

b. Reaction process:

In a 1L three-neck flask equipped with stirring (stirring speed 225rpm), add 190g of phthalic anhydride powder and 350g of α-naphthol powder, stir evenly, add 150ml of methanesulfonic acid, react at 15°C for 9h, and in 10-15 ℃ for 62 hours, then heated to 40 ℃, reacted for 9 hours under stirring, and the liquid color content was 28.50% by sampling.

c. Separation and purification process:

Dissolve the dark green viscous reactant with 4.6L of absolute ethanol, white insoluble matter precipitates out, filter, at this time the filtrate is strongly acidic, adjust with 437ml of 20% (w/w) NaOH (deionized water configuration) The pH value is neutral (tested with test paper), and a large amount of insoluble matter precipitates out, which is slightly viscous. After filtering, the filtrate cools down and insoluble matter precipitates out. Filter again, and rinse the filter cake with a small amount of absolute ethanol. All filtrates were distilled under reduced pressure until no liquid dripped down to recover ethanol. Add 2.8 L of methyl ethyl ketone to the viscous liquid in the bottle after distillation under reduced pressure, heat to boiling, then insoluble matter is precipitated, filter, the filter cake is washed with 1.3 L of methyl ethyl ketone, and the filtrate is distilled under reduced pressure to recover methyl ethyl ketone. The filter cake was washed with 3L of deionized water, transferred to a container and heated to boiling, boiled, filtered, and the filter cake was washed with hot deionized water until the pH of the filtrate was neutral. Dissolve the filter cake with 2L of absolute ethanol, heat it to boiling (completely dissolved), analyze it strongly with 2.25L of distilled water, a light pink solid precipitates out, filter it, and dry the filter cake in an electric drying oven at 35°C to obtain a light pink color The powdery product was 145.1 g, and the yield was 28.67%. The content determined by liquid chromatography is 98.70%.

Claims (8)

1. a preparation method of α-naphtholphthalein, is characterized in that, it comprises following operation: a. Pulverization process: phthalic anhydride and 1-naphthol are pulverized into powder in advance; b. Reaction process: Add the above-mentioned phthalic anhydride and 1-naphthol crushed into powder in the reaction vessel, the molar ratio is 1:1.5～1:2.5; add the catalyst under stirring, and react at the temperature of 0～40°C for more than 3h, Let it stand still for more than 12 hours, then stir and react at 35-60°C for more than 3 hours, take a sample and track it with liquid chromatography, stop the reaction when the content of the main product of the reaction no longer increases, and obtain a viscous reactant; c. Separation and purification process: Dissolve the above viscous reactants with solvent a, filter; neutralize the filtrate with alkali solution, filter, cool down to precipitate, filter; concentrate the filtrate to obtain a viscous liquid; add solvent b to the viscous liquid, heat to boiling, cool down and filter ; transfer the filter cake to a container, add deionized water, heat to boiling, filter, and wash; transfer the filter cake to a container and dissolve it with solvent c, heat to boiling and use deionized water for strong analysis, filter; dry to obtain α- Naphtholphthalein powder. 2. The preparation method according to claim 1, characterized in that the molar ratio of phthalic anhydride to 1-naphthol is 1:1.8 to 1:2.2. 3. preparation method according to claim 2, is characterized in that, described catalyzer is Lewis acid. 4. The preparation method according to claim 3, wherein the catalyst is ZnCl ₂ , AlCl ₃ , TiCl ₄ , concentrated sulfuric acid or methanesulfonic acid. 5. preparation method according to claim 4, described catalyzer is the vitriol oil or methanesulfonic acid. 6. according to the described preparation method of claim 1,2,3,4 or 5, it is characterized in that, described solvent a is ethanol, methyl alcohol or ether, benzene; Described solvent b is chloroform, acetone or butanone; Solvent c is ethanol or methanol. 7. The preparation method according to claim 6, characterized in that, in the b. reaction process, after adding the catalyst, react at a temperature of 10-15°C for more than 3h, let stand for more than 12h, and then react at a temperature of 35-45°C , Stir the reaction for more than 3h. 8. The preparation method according to claim 7, characterized in that, in the b. reaction process, after adding the catalyst, react at a temperature of 10-15°C for 72h, let it stand for more than 12h, and then at 35-45°C, The reaction was stirred for 10-24h.

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