A method for synthesizing tetrahydroanthraquinone epoxy compound

Abstract

The present invention discloses a method for synthesizing a tetrahydroanthraquinone epoxy compound, comprising the following steps: (1) adding tetrahydroanthraquinone and an alkali metal carbonate into a reactor, adding a solvent, and slowly heating the reactor to 50-60° C.; the mass ratio of tetrahydroanthraquinone to sodium carbonate is 10:0-1; (2) adding an oxidant to the solution obtained in step (1) to slowly oxidize the tetrahydroanthraquinone; (3) after the oxidation is completed, adding sodium sulfite to react with an excess of the oxidant until the oxidant content in the reaction solution is less than 0.05 wt (4) cooling the mixed solution obtained in step (3) to crystallize, filter, wash, and dry to obtain the product tetrahydroanthraquinone epoxide. This method is simple to operate, uses cheap and readily available reagents, has high product purity and high yield, and has good promotion and application value.

Description

Technical Field

[0001] The invention relates to the technical field of hydrogen peroxide production, and in particular to a method for synthesizing degradation products in a working solution for producing hydrogen peroxide. Background Art

[0002] Hydrogen peroxide is a colorless, transparent liquid that is miscible with water in any proportion. It can be used for bleaching, three wastes treatment, organic and polymer synthesis, electroplating solution purification, food industry disinfection, as a surface treatment agent and cleaning agent in the electronics industry, as a disinfectant in the medical and pharmaceutical industries, and as a rocket propellant.

[0003] With the successful application of hydrogen peroxide in the green process of producing caprolactam and propylene oxide, its application in chemical synthesis has continued to expand, significantly improving both production efficiency and capacity. In recent years, domestic hydrogen peroxide production capacity has grown at an annual rate of approximately 10%, with a single unit producing 100,000 to 800,000 tons per year. Total domestic production capacity has exceeded 15 million tons per year (equivalent to 27.5% hydrogen peroxide).

[0004] The operation of ultra-large hydrogen peroxide plants places higher demands on the performance of the working fluid, especially the content of degradation products, which has a significant impact on the performance of the working fluid. The determination of degradation product content requires accurate quantitative determination of reference materials. Tetrahydroanthraquinone epoxide, as a degradation product in the working fluid, has a significant impact on the performance of the working fluid. Therefore, obtaining high-purity tetrahydroanthraquinone epoxide is of great significance for the quantitative determination of degradation product content in the working fluid and the evaluation of the working fluid's physical properties. Summary of the Invention

[0005] The present invention aims to provide a method for synthesizing a tetrahydroanthraquinone epoxy compound, which is simple to operate, uses inexpensive and readily available reagents, has high product purity and high yield, and has good promotion and application value.

[0006] The present invention adopts the following technical solutions to achieve the above purpose:

[0007] A method for synthesizing a tetrahydroanthraquinone epoxy compound comprises the following steps:

[0008] (1) Add tetrahydroanthraquinone and alkali metal carbonate into a reactor, add solvent, and slowly heat to 50-60°C; the mass ratio of tetrahydroanthraquinone to alkali metal carbonate is 10:0-1;

[0009] (2) adding an oxidant to the solution obtained in step (1) to slowly oxidize tetrahydroanthraquinone;

[0010] (3) After the oxidation is completed, sodium sulfite is added to react with excess oxidant until the oxidant content in the reaction solution is less than 0.05 wt %;

[0011] (4) The mixed solution obtained in step (3) is cooled and crystallized, filtered, washed, and dried to obtain a tetrahydroanthraquinone epoxy compound as a product. The reaction solvent can be recovered by distillation and reused.

[0012] Furthermore, in step (1), the alkali metal carbonate may be sodium carbonate, potassium carbonate, or sodium bicarbonate. After adding the alkali metal carbonate, the pH value of the solution may be slowly adjusted before the oxidant is added to enhance the oxidation effect and improve the oxidation yield.

[0013] Furthermore, in step (2), the oxidant is percarbonate amide or hydrogen peroxide solution, and the oxidation time is 1 to 10 hours. When the oxidant is percarbonate amide, the amount of alkali metal carbonate added in step (1) is 0; when the oxidant is hydrogen peroxide solution, the mass ratio of tetrahydroanthraquinone to alkali metal carbonate in step (1) is 10:0.5-1, preferably 10:0.75-1.

[0014] Furthermore, the concentration of hydrogen peroxide solution in step (2) is 25-30 wt %, the pH value of the hydrogen peroxide solution is between 3 and 7, preferably between 5 and 7. The pH value of the hydrogen peroxide solution is adjusted by adding an alkali metal carbonate solution, because hydrogen peroxide is relatively stable at a lower pH value and decomposes too quickly when the pH value is greater than 7. Therefore, when the pH value is between 5 and 7, more active oxygen is generated by decomposition and the utilization rate of hydrogen peroxide is higher.

[0015] Furthermore, in step (2), the oxidant is added by slowly adding hydrogen peroxide solution or percarbonate amide solid. The oxidant cannot be added all at once to avoid excessive reaction or ineffective decomposition of hydrogen peroxide.

[0016] Furthermore, in step (2), the amount of hydrogen peroxide solution added is 1-100% of the mass of tetrahydroanthraquinone or the amount of percarbonic acid amide added is 1-50% of the mass of tetrahydroanthraquinone.

[0017] Furthermore, in step (3), the amount of sodium sulfite added is 1 to 40% of the mass of tetrahydroanthraquinone. By adding sodium sulfite, unreacted oxidant can be removed, making the solvent recovery process safer.

[0018] Furthermore, in step (1), the tetrahydroanthraquinone is tetrahydro-2-ethylanthraquinone as shown in Formula 1 or tetrahydro-2-pentylanthraquinone as shown in Formula 2, and the amount of solvent added is 5 to 10 times the mass of the tetrahydroanthraquinone. The solvent can be recovered by distillation and reused, and the solvent is preferably ethanol.

[0019] .

[0020] Furthermore, in step (4), the tetrahydroanthraquinone epoxy compound is a tetrahydro-2-ethylanthraquinone epoxy compound as shown in Formula 3 or a tetrahydro-2-pentylanthraquinone epoxy compound as shown in Formula 4.

[0021] .

[0022] Furthermore, the purity of the tetrahydroanthraquinone epoxy compound is greater than 99.5%. The product prepared by the present invention has high purity and good uniformity, and can be used as a standard sample to quantitatively determine the accurate content of its components in the working solution.

[0023] Furthermore, after adding the solvent in step (1), ferrous sulfate solid is added, and the amount of ferrous sulfate solid added is 5 to 10 of the mass of sodium carbonate. wt %.

[0024] The present invention has the following beneficial effects:

[0025] (1) After adding the alkali metal carbonate in step (1), the pH value of the solution can be slowly adjusted before the oxidant is added to enhance the oxidation effect and improve the oxidation yield;

[0026] (2) After the oxidation is completed, the unreacted oxidant can be removed by adding sodium sulfite, making the solvent recovery process safer;

[0027] (3) The addition of ferrous sulfate in the present invention has a certain catalytic effect, promoting the formation of tetrahydroanthraquinone epoxides. At the same time, ferrous sulfate reacts with alkali metal carbonates to generate ferrous hydroxide, which also has a catalytic effect. In addition, ferrous hydroxide is converted into ferric hydroxide in the presence of hydrogen peroxide, which has a synergistic catalytic effect, improves the oxidation effect, and improves the product purity and yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a liquid chromatogram of the product of Example 1;

[0029] Figure 2 This is an enlarged view of the peak table in the liquid chromatogram of the product in Example 1;

[0030] Figure 3 This is a liquid chromatogram of the product of Example 2;

[0031] Figure 4 It is an enlarged view of the peak table in the liquid chromatogram of the product in Example 2. DETAILED DESCRIPTION

[0032] The present invention is further described below with reference to the embodiments. The present invention is not limited to the embodiments. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the scope of protection and disclosure of the present invention.

[0033] Example 1

[0034] Synthesis of Tetrahydro-2-ethylanthraquinone Epoxide:

[0035] (1) Add 20 g of tetrahydro-2-ethylanthraquinone into the reactor, add 100 g of ethanol, and slowly heat to 50-55 °C;

[0036] (2) Slowly add 4 g of percarbonic acid amide solid to the solution obtained in step (1) and the oxidation time is 10 h;

[0037] (3) After oxidation is completed, add 3g of sodium sulfite;

[0038] (4) The mixed solution obtained in step (3) was cooled and crystallized, filtered, washed, and dried to obtain 19.66 g of tetrahydro-2-ethylanthraquinone epoxide with a purity of 99.6% and a yield of 95.7%. The reaction solvent was recovered by distillation and could be reused.

[0039] Example 2

[0040] Synthesis of Tetrahydro-2-ethylanthraquinone Epoxide:

[0041] (1) Add 20 g of tetrahydro-2-ethylanthraquinone and 2 g of sodium carbonate into a reactor, add 200 g of ethanol, and slowly heat to 55-60 °C;

[0042] (2) Slowly add 15 ml of 25% hydrogen peroxide solution to the solution obtained in step (1) for 2 hours; the pH value of the hydrogen peroxide solution is between 5 and 7, and the pH value of the hydrogen peroxide solution is adjusted by adding sodium carbonate solution;

[0043] (3) After the oxidation is completed, add 4 g of sodium sulfite and react with excess oxidant until the hydrogen peroxide content in the reaction solution is less than 0.05%;

[0044] (4) The mixed solution obtained in step (3) was cooled and crystallized, filtered, washed, and dried to obtain 20.3 g of tetrahydro-2-ethylanthraquinone epoxide with a purity of 99.7% and a yield of 98.2%. The reaction solvent was recovered by distillation and could be reused.

[0045] Example 3

[0046] Synthesis of Tetrahydro 2-pentylanthraquinone Epoxide:

[0047] (1) Add 20 g of tetrahydro-2-pentylanthraquinone and 1 g of sodium carbonate into a reactor, add 150 g of ethanol, and slowly heat to 55-60 °C;

[0048] (2) Slowly add 10 ml of 30% hydrogen peroxide solution to the solution obtained in step (1) for 4 hours; the pH value of the hydrogen peroxide solution is between 3 and 4, and the pH value of the hydrogen peroxide solution is adjusted by adding sodium carbonate solution;

[0049] (3) After the oxidation is completed, add 2 g of sodium sulfite and react with excess oxidant until the hydrogen peroxide content in the reaction solution is less than 0.05%;

[0050] (4) The mixed solution obtained in step (3) was cooled and crystallized, filtered, washed, and dried to obtain 19.31 g of the product tetrahydro 2-pentyl anthraquinone epoxide with a purity of 99.59% and a yield of 95.2%. The reaction solvent was recovered by distillation and could be reused.

[0051] Example 4

[0052] Synthesis of Tetrahydro 2-pentylanthraquinone Epoxide:

[0053] (1) Add 20 g of tetrahydro-2-pentylanthraquinone and 1.5 g of sodium carbonate into a reactor, add 120 g of ethanol, and slowly raise the temperature to 55-60 °C;

[0054] (2) Slowly add 18 ml of 27.5% hydrogen peroxide solution to the solution obtained in step (1) for 5 hours; the pH value of the hydrogen peroxide solution is between 3 and 4, and the pH value of the hydrogen peroxide solution is adjusted by adding sodium carbonate solution;

[0055] (3) After the oxidation is completed, 6 g of sodium sulfite is added and reacted with excess oxidant until the hydrogen peroxide content in the reaction solution is less than 0.05%;

[0056] (4) The mixed solution obtained in step (3) was cooled and crystallized, filtered, washed, and dried to obtain 19.71 g of the product tetrahydro 2-pentyl anthraquinone epoxide with a purity of 99.56% and a yield of 96.3%. The reaction solvent was recovered by distillation and could be reused.

[0057] Example 5

[0058] The difference between Example 5 and Example 4 is that 0.15 g of ferrous sulfate is added after the addition of ethanol in step (1). The remaining steps are the same as those in Example 4 and are not described in detail. In the final step (4), the product purity is 99.92% and the yield is 97.4%. The addition of ferrous sulfate has a certain catalytic effect. At the same time, ferrous sulfate and sodium carbonate react to form ferrous hydroxide, which has a catalytic effect and improves the oxidation effect, thereby increasing both the product purity and yield.

[0059] Comparative Example 1

[0060] Comparative Example 1 differs from Example 4 in that sodium carbonate is not added in step (1). The remaining steps are the same as in Example 4 and are not described in detail. The product purity in the final step (4) is 87.2%, and the yield is 89.2%. This indicates that the addition of sodium carbonate can further adjust the pH of the reaction solution to between 8 and 10, thereby improving the oxidation effect.

[0061] Comparative Example 2

[0062] Comparative Example 2 differs from Example 4 in that the hydrogen peroxide solution in step (2) is commercially available hydrogen peroxide (pH between 1 and 2.9) and the pH is not adjusted. The remaining steps are the same as in Example 4 and are not described in detail. The product purity in the final step (4) is 75.3% and the yield is 84.2%. The pH of the reaction solution gradually decreases with the addition of hydrogen peroxide, affecting the reaction effect.

[0063] Comparative Example 3

[0064] The difference between Comparative Example 3 and Example 4 is that step (3) is removed, and the rest is the same as Example 4 and will not be repeated; in the final step (4), a large amount of bubbles are generated during the solvent recovery stage, which is prone to boiling and poses a serious safety hazard.

[0065] Comparative Example 4

[0066] Comparative Example 4 differs from Example 5 in that 0.5 g of ferrous sulfate is added after the addition of ethanol in step (1). The remaining steps are the same as in Example 4 and are not described in detail. The product purity in the final step (4) is 82.3% and the yield is 91.2%. If the amount of ferrous sulfate added is too large, a Fenton oxidation side reaction may occur, resulting in a decrease in the quality of the final product, a dark color, and poor quality.

Claims

1. A method for synthesizing a tetrahydroanthraquinone epoxy compound, comprising the following steps: (1) Add tetrahydroanthraquinone and alkali metal carbonate into a reactor, add solvent, and slowly heat to 50-60°C; (2) adding an oxidant to the solution obtained in step (1) to slowly oxidize tetrahydroanthraquinone; (3) After the oxidation is completed, sodium sulfite is added to react with excess oxidant until the oxidant content in the reaction solution is less than 0.05 wt %; (4) cooling the mixed solution obtained in step (3) to crystallize, filter, wash, and dry to obtain a tetrahydroanthraquinone epoxy compound; In step (1), the tetrahydroanthraquinone is tetrahydro 2-ethylanthraquinone as shown in formula 1 or tetrahydro 2-pentylanthraquinone as shown in formula 2 ； In step (4), the tetrahydroanthraquinone epoxy compound is a tetrahydro 2-ethylanthraquinone epoxy compound as shown in formula 3 or a tetrahydro 2-pentylanthraquinone epoxy compound as shown in formula 4 ； In step (1), after adding the solvent, ferrous sulfate solid is added, and the amount of ferrous sulfate solid added is 5-10% of the mass of the alkali metal carbonate. wt %; The oxidant is a hydrogen peroxide solution, and the mass ratio of tetrahydroanthraquinone to alkali metal carbonate in step (1) is 10:0.5-1.

2. The synthesis method according to claim 1, wherein In step (1), the alkali metal carbonate is selected from one or more of sodium carbonate, potassium carbonate, and sodium bicarbonate.

3. The synthesis method according to claim 1, wherein In step (1), the mass ratio of tetrahydroanthraquinone to alkali metal carbonate is 10:0.75-1.

4. The synthesis method according to claim 1, characterized in that The concentration of hydrogen peroxide solution in step (2) is 25~30 wt %, the pH value of the hydrogen peroxide solution is between 3 and 7, and the pH value of the hydrogen peroxide solution is adjusted by adding an alkali metal carbonate solution.

5. The synthesis method according to claim 4, characterized in that The pH value of the hydrogen peroxide solution in step (2) is 5-7.

6. The synthesis method according to claim 1, characterized in that In step (2), the amount of hydrogen peroxide solution added is 1 to 100% of the mass of tetrahydroanthraquinone.

7. The synthesis method according to claim 1, characterized in that In step (3), the amount of sodium sulfite added is 1 to 40% of the mass of tetrahydroanthraquinone.

8. The synthesis method according to any one of claims 1 to 7, characterized in that In step (4), the purity of the tetrahydroanthraquinone epoxide compound is greater than 99.5%.

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