TW201912567A - Method for producing hydrogen peroxide - Google Patents

Abstract

The present invention provides a method for obtaining a high-quality regenerating working solution by removing an inert material from a working solution containing trioctyl phosphate (TOP). The production method of hydrogen peroxide includes: a hydrogen peroxide production step for hydrogenating a working solution containing aromatic hydrocarbons, TOP and anthraquinones to produce hydrogen peroxide by oxidation and extracting the hydrogen peroxide from the working solution, and returning the working solution after the hydrogen peroxide extraction to the hydrogenation process for repeating the process; and a working solution regeneration step for removing an inert material produced as a result of the production of hydrogen peroxide from the working solution so as to prepare a crude regenerating working solution, and performing an alkaline cleaning process on the crude regenerating working solution to prepare the regenerating working solution for repeating the process. The working solution regeneration step includes: (i) a first distillation step for recovering aromatic hydrocarbon by performing distillation under the atmospheric pressure or a lower pressure; and (ii) a second distillation step for recovering anthraquinones and TOP by performing distillation at 160 DEG C or a higher temperature under a lower pressure.

Description

Production method of hydrogen peroxide

The present invention relates to a method for producing hydrogen peroxide using anthraquinones, and particularly to a method for producing hydrogen peroxide using a regeneration step of a working solution.

Hydrogen peroxide has oxidizing power and has a strong bleaching and sterilizing effect. Therefore, it is used as a bleaching agent, bactericide, and the like for paper, wood pulp, and fibers. The decomposition products of hydrogen peroxide are water and oxygen. Therefore, from the perspective of environmental protection, it is placed in an important position, especially as a substitute for chlorine-based bleach. Furthermore, in the semiconductor industry such as cleaning of semiconductor substrate surfaces, chemical polishing of copper, tin and other copper alloy surfaces, and etching of electronic circuits, the amount of hydrogen peroxide used has also increased. In addition, hydrogen peroxide is widely used in oxidation reactions mainly based on epoxidation and hydroxylation, and is an important industrial product.

As an industrial hydrogen peroxide production method, the anthraquinone method is known. In this method, anthraquinones are dissolved in an organic solvent to obtain a working solution. In the hydrogenation step, anthraquinones are hydrogenated in the presence of a hydrogenation catalyst to generate anthrahydroquinones. Then, in the oxidation step, the anthrahydroquinones are converted into anthraquinones again, and at the same time, hydrogen peroxide is generated. Hydrogen peroxide in the working solution is separated from the working solution by methods such as water extraction. The working solution from which the hydrogen peroxide has been extracted is returned to the hydrogenation step, and a cycle treatment is formed.

In the process of repeatedly hydrogenating anthraquinones contained in the working solution to anthrahydroquinones and oxidizing them to anthraquinones to produce hydrogen peroxide, tetrahydroanthracene that does not contribute to the generation of hydrogen peroxide is generated. Anthraquinone monomer by-products such as quinone epoxide, tetraoxonone, oxidone ketone, allium ketone, anthraquinone solvent adducts, and anthraquinone polymers. In addition, degradation products of the solvent components are also generated. Such ingredients that do not involve the production of hydrogen peroxide are classified as "inert substances". The increase in this inert substance may cause a decrease in the concentration of the anthraquinones, which is the active substance, and may reduce the ability of each step of the cycle treatment. Therefore, a working solution having a low concentration of the inert substance and a sufficiently high concentration of the active substance is required (Patent Document 1). [Prior Art Literature] [Patent Literature]

[Patent Document 1] WO2007 / 129769

(Problems to be Solved by the Invention)

The composition of the working solution varies depending on the hydrogen peroxide manufacturing plant, but it is often used as a non-polar solvent containing aromatic hydrocarbons, ginseng phosphate (2-ethylhexyl) (CAS number: 78-42-2, sometimes described below) "Trioctyl phosphate" or "TOP") as a polar solvent, alkyl anthraquinone and alkyl tetrahydroanthraquinone as a working solution of anthraquinones. However, there has been no method to suppress the concentration of the inert substance and maintain the concentration of the active substance in a working solution containing trioctyl phosphate as a polar solvent. It is therefore an object of the present invention to provide a method for removing inert substances from a trioctyl phosphate-containing working solution used in the production of hydrogen peroxide by the anthraquinone method and maintaining or improving the physical properties and / or activity of the working solution. (The way to solve the problem)

In order to solve the above-mentioned problems, the inventor of the present case has made intensive research, and as a result, found a method for removing by-products from a working solution containing an aromatic hydrocarbon, trioctyl phosphate, and anthraquinones. This method uses distillation to recover aromatic hydrocarbons at atmospheric pressure or lower, and then distills above 160 ° C at a lower pressure to recover anthraquinones and trioctyl phosphate, and recovers the entire distillate. Reuse as working solution. Further, the inventors of the present case continued their research and found that the hydrogenated activity was improved by alkaline washing the regenerated working solution.

One aspect of the present invention is as follows. [1] A method for producing hydrogen peroxide, comprising the following steps: The step for producing hydrogen peroxide is to hydrogenate a working solution containing aromatic hydrocarbons, trioctyl phosphate, and anthraquinones and then oxidize them to produce them. Hydrogen peroxide, the hydrogen peroxide is extracted from the working solution, so that the working solution after the hydrogen peroxide has been extracted is returned to the hydrogenation step to be circulated; the working solution regeneration step is accompanied by the hydrogen peroxide from the working solution. The by-products produced by-products are removed, and a crude regeneration working solution from which the inert substances have been removed is prepared; and a step of preparing a recycling regeneration working solution for recycling, subjecting the crude regeneration working solution to alkaline washing, and preparing a recycling regeneration working solution; The working solution regeneration step has the following steps: i) a first distillation step, which uses aromatic distillation at atmospheric pressure or lower to recover aromatic hydrocarbons; and ii) a second distillation step, which second uses a lower pressure and 160 Distillation above ℃ to recover anthraquinones and trioctyl phosphate.

[2] The method for producing hydrogen peroxide according to [1], wherein the pressure in the first distillation step is in a range of 1 kPa to 100 kPa. [3] The method for producing hydrogen peroxide according to [1] or [2], wherein the pressure in the second distillation step is 1 kPa or less. [4] The method for producing hydrogen peroxide according to any one of [1] to [3], wherein the temperature in the second distillation step is in a range of 160 ° C to 300 ° C. [5] The method for producing hydrogen peroxide according to any one of [1] to [4], wherein the anthraquinones include an alkylanthraquinone and an alkyltetrahydroanthraquinone. [6] The method for producing hydrogen peroxide according to any one of [1] to [5], including the step of returning the regenerating working solution for recycling to the hydrogen peroxide production step.

[7] The method for producing hydrogen peroxide according to [6], wherein the solvent composition ratio of the crude regenerating working solution is within a range of ± 20% relative to the solvent composition ratio of the working solution circulated in the hydrogen peroxide production step. . [8] The method for producing hydrogen peroxide according to [6] or [7], wherein the concentration of anthraquinones in the crude regeneration working solution is anthraquinones in the working solution circulated in the hydrogen peroxide production step The concentration is within a range of not less than the saturation concentration of the anthraquinones. [9] The method for producing hydrogen peroxide according to any one of [6] to [8], wherein in the step of preparing the regenerating working solution for recycling, the regenerating working solution is adjusted to 20% to 160% of the saturated water content . [10] The method for producing hydrogen peroxide according to any one of [6] to [9], wherein the step of preparing the regenerating working solution for recycling further includes a step of washing the regenerating working solution after washing with alkali. [11] The method for producing hydrogen peroxide according to any one of [1] to [10], further comprising a step of separating anthraquinones from trioctyl phosphate from a distillate of the second distillation step. [12] The method for producing hydrogen peroxide according to [11], wherein the step of separating the anthraquinones from trioctyl phosphate is performed by recrystallization.

[13] A hydrogen peroxide manufacturing system, including a distillation column, a preparation tank, a cleaning tank, a hydrogenation column, an oxidation tower, and an extraction column; the distillation column includes an unknown component discharge line; and the distillation column and the preparation tank are supplied by a previous stage distillation distillate And the subsequent distillation distillate supply line, the preparation tank and the cleaning tank are connected by the crude regeneration working solution supply line, the cleaning tank is connected with the alkaline solution supply line and the water supply line, and the cleaning tank has a waste liquid line The cleaning tank and the hydrogenation tower communicate with each other by using a regeneration working solution supply line for recycling. The hydrogenation tower is connected with a hydrogenation agent supply line. The hydrogenation tower and the oxidation tower are connected by a hydrogenation working solution supply line. The oxidation tower is connected with an oxidant supply line to oxidize. The tower and the extraction tower are connected by an oxidation working solution supply line. The extraction tower is provided with a hydrogen peroxide delivery line. The distillation tower and the extraction tower are connected by a supply line of the extracted working solution of hydrogen peroxide. [14] The hydrogen peroxide manufacturing system according to [13] further includes a front stage distillation distillate tank. The distillation tower and the front stage distillation distillate tank are connected by a front stage distillation distillate conveying line. The preparation tank is communicated by a front-stage distillation distillate supply line. [15] The hydrogen peroxide manufacturing system according to [13] further includes a rear-stage distillation distillate tank, and the distillation tower and the rear-stage distillation distillate tank are connected by a back-stage distillation distillate conveying line, and the rear-stage distillation distillate tank is connected with The preparation tank is communicated by a rear-stage distillation distillate supply line. [16] The hydrogen peroxide production system according to [13], further including a recrystallization tank, the recrystallization tank is equipped with a filter and a waste liquid line, the recrystallization tank is connected with a recrystallization solvent supply line, and the recrystallization tank and the distillation column use the latter stage distillation The distillate supply line is connected, and the recrystallization tank and the preparation tank are connected by an anthraquinone-based supply line. (Effect of the invention)

The present invention exhibits one or more of the following effects. (1) The inert material can be removed from a working solution containing trioctyl phosphate as a polar solvent in which the inert material is accumulated. (2) Anthraquinones, which are active materials, can be efficiently recovered and reused from working solutions containing trioctyl phosphate as a polar solvent. (3) By reducing the inert substances in the circulating working solution, it is possible to maintain the high efficiency of each step in the production of hydrogen peroxide. (4) The viscosity of the circulating working solution can be maintained low. (5) It can maintain a high hydrogenation activity of the circulating working solution. (6) It can be used in trioctyl phosphate-containing working solutions that are used frequently, so it can be used in a wide range, and it can be expected to make a significant contribution to the efficiency of hydrogen peroxide production.

One aspect of the present invention relates to a method for producing hydrogen peroxide (hereinafter sometimes referred to as "the method for producing hydrogen peroxide according to the present invention"), which is characterized in that it includes the following steps: Hydrogen peroxide (trioctyl phosphate) and anthraquinone working solutions are hydrogenated (reduced) and oxidized to generate hydrogen peroxide. The hydrogen peroxide is extracted from the working solution so that the hydrogen peroxide has been extracted from the working solution. Return to the hydrogenation step to circulate it; a working solution regeneration step, from which the inert substance that is by-produced with the generation of the hydrogen peroxide is removed, and a crude regeneration working solution from which the inert substance has been removed is prepared; and for recycling Regeneration working solution preparation step. The crude regeneration working solution is subjected to alkaline washing, and a regenerating working solution is prepared. The working solution regeneration step has the following steps: i) a first distillation step, which is performed at atmospheric pressure or lower Distillation to recover aromatic hydrocarbons; and ii) a second distillation step, followed by distillation at a lower pressure and above 160 ° C to recover anthracene Class and trioctyl phosphate.

The aromatic hydrocarbons contained in the working solution are not limited, for example: aromatic hydrocarbons substituted with at least 1 alkyl group, especially alkylbenzenes containing 8, 9, 10, 11 or 12 carbon atoms (for example, 9 carbon Atomic trimethylbenzene, etc.) or a mixture thereof is preferably one capable of dissolving anthraquinone. In a specific aspect, the aromatic hydrocarbon is selected from a mixed solvent having 10 carbon atoms and a mixed solvent having 9 carbon atoms (for example, a cumene isomer mixture). Trioctyl phosphate which is a polar solvent is a compound having the following structure. [Chemical 1]

The anthraquinones contained in the working solution include at least one of anthraquinone (9,10-anthracene dione), tetrahydroanthraquinone, and derivatives thereof capable of generating hydrogen peroxide by the anthraquinone method. The anthraquinone derivative capable of generating hydrogen peroxide is not limited, and examples thereof include alkyl anthraquinone. Alkyl anthraquinone refers to anthraquinone substituted with at least one alkyl group. In a specific aspect, the alkylanthraquinone includes anthraquinone having at least one substitution at the 1, 2 or 3 position by a linear or branched aliphatic substituent containing at least one carbon atom. The alkyl substituent in the alkyl anthraquinone preferably contains 1 to 9, more preferably 1 to 6 carbon atoms. Specific examples of the alkylanthraquinone are not limited, for example, methylanthraquinone (2-methylanthraquinone, etc.), dimethylanthraquinone (1,3-, 2,3-, 1,4-, 2, 7-dimethylanthraquinone, etc.), ethylanthraquinone (2-ethylanthraquinone, etc.), propylanthraquinone (2-n-propylanthraquinone, 2-isopropylanthraquinone, etc.), butylanthracene Quinones (2-second butyl anthraquinone, 2-third butyl anthraquinone, etc.), pentyl anthraquinone (2-second pentyl anthraquinone, 2-third pentyl anthraquinone, etc.) and the like. Preferred alkylanthraquinones include ethylanthraquinone, pentylanthraquinone, and mixtures thereof. The concentration of alkyl anthraquinones in the working solution can be controlled according to the processing conditions. For example, it can be used in a concentration range of 0.4 to 1.0 mol / L.

The tetrahydroanthraquinone derivative capable of generating hydrogen peroxide is not limited, and examples thereof include alkyl tetrahydroanthraquinone. Alkyltetrahydroanthraquinone refers to tetrahydroanthraquinone substituted with at least one alkyl group. In a specific aspect, the alkyltetrahydroanthraquinone includes a tetrahydroanthraquinone substituted for at least one of the 1, 2 or 3 positions by a linear or branched aliphatic substituent containing at least 1 carbon atom. The alkyl substituent in the alkyltetrahydroanthraquinone preferably contains 1 to 9, more preferably 1 to 6 carbon atoms. Specific examples of the alkyltetrahydroanthraquinone are not limited, for example, methyltetrahydroanthraquinone (2-methyltetrahydroanthraquinone, etc.), dimethyltetrahydroanthraquinone (1,3-, 2,3-, 1,4-, 2,7-dimethyltetrahydroanthraquinone, etc.), ethyltetrahydroanthraquinone (2-ethyltetrahydroanthraquinone, etc.), propyltetrahydroanthraquinone (2-n-propyltetrahydroquinone) Hydroanthraquinone, 2-isopropyltetrahydroanthraquinone, etc.), butyltetrahydroanthraquinone (2-second butyltetrahydroanthraquinone, 2-third butyltetrahydroanthraquinone, etc.), pentyltetrahydroanthraquinone Hydroanthraquinone (2-second pentyltetrahydroanthraquinone, 2-third pentyltetrahydroanthraquinone, etc.) and the like. Preferred alkyltetrahydroanthraquinones include ethyltetrahydroanthraquinone, pentyltetrahydroanthraquinone, or a mixture thereof.

In one aspect, the working solution includes a combination of an alkylanthraquinone and an alkyltetrahydroanthraquinone. In this combination, the molar ratio of alkylanthraquinone to alkyltetrahydroanthraquinone is not particularly limited. The alkylanthraquinone: alkyltetrahydroanthraquinone is preferably 0.05: 1 to 100: 1, and 0.1: 1 to 75: 1 is better, 0.2: 1 ~ 50: 1 is even better. In addition, the weight ratio of alkylanthraquinone to alkyltetrahydroanthraquinone is also not particularly limited. The alkylanthraquinone: alkyltetrahydroanthraquinone is preferably 0.05: 1 to 100: 1, and 0.1: 1 to 75: 1 is better, 0.2: 1 ~ 50: 1 is even better. A particularly desirable combination of alkylanthraquinone and alkyltetrahydroanthraquinone is a combination of ethylanthraquinone and ethyltetrahydroanthraquinone.

The hydrogen peroxide production step can be carried out according to a known method for producing hydrogen peroxide using the anthraquinone method. The hydrogen peroxide manufacturing steps generally include the following steps: hydrogenating the working solution, oxidizing the hydrogenated working solution, and extracting hydrogen peroxide generated by the oxidation into the aqueous phase. The hydrogenation of the working solution can be carried out, for example, by bubbling the working solution with a hydrogen-containing gas such as a mixture of hydrogen, an inert gas (nitrogen, etc.) and hydrogen in the presence of a hydrogenation catalyst. Oxidation of the hydrogenated working solution can be performed, for example, by bubbling the working solution with an oxygen-containing gas such as air or oxygen. The extraction of hydrogen peroxide into the aqueous phase can be performed by, for example, mixing the oxidized working solution with water and separating the aqueous phase. After that, the extracted hydrogen peroxide may be subjected to purification, concentration, and the like.

In the working solution regeneration step, the removal of inert substances from the working solution is performed by a distillation step including the following steps: i) the first distillation step (hereinafter sometimes referred to as the first-stage distillation step), which is used at atmospheric pressure or lower Distilling to recover aromatic hydrocarbons; ii) a second distillation step (hereinafter sometimes referred to as the post-stage distillation step), followed by distillation at a lower pressure and above 160 ° C. to recover anthraquinones and trioctyl phosphate.

In the first distillation step, the working solution is distilled at a pressure below atmospheric pressure, and the aromatic hydrocarbon contained in the working solution is recovered as a distillate. The distillation pressure is not particularly limited as long as it is a pressure capable of recovering aromatic hydrocarbons, for example, 0.5 kPa to 100 kPa, 0.8 kPa to 100 kPa, 1 kPa to 100 kPa, 1 kPa to 50 kPa, and the like. It is preferred that the distillation pressure at which the aromatic hydrocarbons are distilled but trioctyl phosphate and anthraquinones are not distilled is preferred. The distillation temperature is not particularly limited as long as it is a distillation temperature capable of recovering aromatic hydrocarbons, and may be, for example, 110 ° C to 240 ° C, 120 ° C to 220 ° C, 130 ° C to 200 ° C, 140 ° C to 190 ° C, 150 ° C ~ 185 ° C and so on. It is preferred that the distillation temperature at which the aromatic hydrocarbons are distilled but trioctyl phosphate and anthraquinones are not distilled is preferred. Distillation in the first distillation step, considering the recovery of aromatic hydrocarbons and other viewpoints, it is preferable to continue the distillation until there is no more distillation. The aromatic hydrocarbons distilled in the first distillation step are reused as a component of a regeneration working solution.

The working solution for the first distillation step is generally a working solution circulated in the hydrogen peroxide production step, and contains an inert substance that is by-produced with the generation of hydrogen peroxide. The working solution can be a working solution taken from any stage of the hydrogen peroxide manufacturing step but containing no hydrogen peroxide, or even after the extraction step with a very small content (for example: 0.35 g / L or less), considering safety The view is ideal. Inert substances, such as byproducts (oxides, decomposition products, etc.) from anthraquinones, solvents (aromatic hydrocarbons, and trioctyl phosphate). Byproducts derived from anthraquinones, such as tetrahydroanthraquinone epoxide, tetraoxanthone, oxyonionone, allium ketone and other anthraquinone monomer byproducts, anthraquinone solvent adducts, anthracene Polymers of quinones, etc. By-products from solvents, such as carboxylic acids, polyols, phenols, etc.

In the second distillation step, the residue obtained in the first distillation step is subjected to distillation at a temperature of 160 ° C. or higher at a lower pressure than that in the first distillation step, and anthraquinones and trioctyl phosphate are recovered as distillates. This can remove by-products (high-boiling components) having higher boiling points than anthraquinones and trioctyl phosphate. The distillation pressure is not particularly limited as long as it can recover anthraquinones and trioctyl phosphate, for example: 0.001kPa ~ 1kPa, 0.002kPa ~ 0.5kPa, 0.005kPa ~ 0.2kPa, 0.008kPa ~ 0.1kPa, 0.1kPa ~ 0.3kPa, etc. . Preferably, the distillation pressure is such that anthraquinones and trioctyl phosphate will distill, but less by-products are distilled. The distillation temperature is not particularly limited as long as anthraquinones and trioctyl phosphate can be recovered, for example: 160 ° C to 300 ° C, 165 ° C to 280 ° C, 170 ° C to 270 ° C, 175 ° C to 260 ° C, 220 ° C to 260 ° C and so on. In some aspects, the upper limit of the distillation temperature in the second distillation step may not reach 200 ° C. Therefore, in this aspect, the distillation temperature range of the second distillation step may be, for example: 160 ° C ~ 199 ° C, 160 ° C ~ 198 ° C, 160 ° C ~ 197 ° C, 160 ° C ~ 196 ° C, 160 ° C ~ 195 ° C, 160 ℃ ~ 194 ℃, 160 ℃ ~ 193 ℃, 160 ℃ ~ 192 ℃, 160 ℃ ~ 191 ℃, 160 ℃ ~ 190 ℃, 160 ℃ ~ 189 ℃, 160 ℃ ~ 188 ℃, 160 ℃ ~ 187 ℃, 160 ℃ ~ 186 ℃, 160 ℃ ~ 185 ℃, 160 ℃ ~ 184 ℃, 160 ℃ ~ 183 ℃, 160 ℃ ~ 182 ℃, 160 ℃ ~ 181 ℃, 160 ℃ ~ 180 ℃ and so on. The distillation temperature should preferably be such that the anthraquinones and trioctyl phosphate will distill, but the by-products will distill less.

The distillation in the second distillation step is preferably continued until the distillation is no longer considered in consideration of the recovery rate of the anthraquinones. The average residence time in the second distillation step is not particularly limited, but is, for example, 1 hour or more. "Residence time" refers to the time from the beginning of distillation or bottom production (bottom production) to the stop in the distillation step. "Average residence time" refers to the simple arithmetic mean of the residence time when the same distillation step is performed more than two times. . The average residence time in the second distillation step may be, for example, a range of 1 hour to 10 hours, a range of 6 hours to 10 hours, and the like. If the average residence time is more than 1 hour, the recovery rate of anthraquinones will be improved, and the by-products from anthraquinones will be converted into anthraquinones with hydrogen peroxide production capacity, and there will be Benefits of an increased amount of anthraquinones. For example, the by-product tetrahydroanthraquinone epoxide will be converted into tetrahydroanthraquinone with the ability to produce hydrogen peroxide. The anthraquinones and trioctyl phosphate distilled in the second distillation step are reused as components of a regeneration working solution.

The device used in the distillation step is not particularly limited as long as it can perform distillation at a predetermined temperature and pressure, such as a batch distillation device, a continuous distillation device, a thin film distillation device, and the like. From the viewpoint of cost and the like, a distillation apparatus that can be used in both the first distillation step and the second distillation step is preferable.

In one aspect, the method for producing hydrogen peroxide according to the present invention further includes the steps of separating anthraquinones and trioctyl phosphate from the distillate of the second distillation step. The separation of anthraquinones from trioctyl phosphate can be carried out by recrystallizing the anthraquinones. Recrystallization of anthraquinones can be performed by heating anthraquinones, dissolving them in a recrystallization solvent, and then cooling them. After recrystallization, the recrystallized anthraquinones can be recovered and reused. Trioctyl phosphate isolated from anthraquinones can be reused by separating it from a recrystallization solvent by distillation or the like. The recrystallization solvent is preferably the one having a large difference between the solubility of the anthraquinones under heating and the solubility during cooling. Non-limiting examples of the recrystallization solvent include alcohol-based solvents (for example, lower alcohols such as methanol, ethanol, propanol, isopropanol, butanol, and tertiary butanol, 2-ethylhexanol, etc.), and as working solutions. Non-polar solvents (aromatic hydrocarbons, etc.), polar solvents (TOP, diisobutyl methanol, tetrabutyl urea, methyl cyclohexyl acetate, etc.) used for the components, and the like. The recrystallization solvent may be composed of a single solvent or a mixture of a plurality of solvents. The amount of recrystallization solvent relative to the working solution is preferably an anthraquinone. Recrystallization can be performed well, for example, it can be the volume of the solvent per unit weight of the working solution (eg, g / mL). It is 1-20 times, 2-15 times, 3-10 times, 4-8 times, etc. By including a step of separating anthraquinones from trioctyl phosphate, the anthraquinones can be recovered in a more pure form. Therefore, the concentration of by-products contained in the regeneration working solution can be further reduced.

In the working solution regeneration step, the crude regeneration working solution can be prepared by mixing the aromatic hydrocarbon recovered in the first distillation step and the anthraquinones and trioctyl phosphate recovered in the second distillation step. In the aspect including the step of separating anthraquinones and trioctyl phosphate from the distillate of the second distillation step, the crude regeneration working solution can be prepared by the aromatic hydrocarbons to be recovered in the first distillation step, and the first 2 Anthraquinones and trioctyl phosphate recovered after the distillation step are mixed for implementation. In this specification, the crude regeneration working solution refers to the regeneration working solution containing the aromatic hydrocarbons, trioctyl phosphate, and anthraquinones recovered in the distillation step before alkali cleaning.

If the solvent composition ratio in the working solution changes, the density, viscosity, and partition coefficient of the working solution also change. If these parameters change, the operating conditions and equipment of each step also need to be changed, which is not ideal from the viewpoint of stable production of hydrogen peroxide. Therefore, the solvent composition ratio of the regenerating working solution should be adjusted to be close to that of the working solution in the recycling process. For example: the solvent composition ratio (%) of the regenerating working solution should be adjusted to within ± 20% points, preferably within ± 10% points, and more preferably within ± 5% points relative to the circulating processing working solution (but adjusted The total composition ratio of the following solvents does not exceed 100%). That is, when the solvent of the working solution is composed of an aromatic hydrocarbon and trioctyl phosphate, and the solvent composition ratio (volume ratio) in the circulation treatment is aromatic hydrocarbon: trioctyl phosphate = 70%: 30%, it should be adjusted to The solvent composition ratio of the regeneration working solution is 90%: 10% to 50%: 50%, preferably 80%: 20% to 60%: 40%, and more preferably 75%: 25% to 65%: 35%.

In an actual factory, the concentration of anthraquinones in the working solution in the circulation process gradually decreases with the passage of time, so it is operated while supplementing new anthraquinones appropriately. In order not to reduce the concentration of anthraquinones in the recycling process, the concentration of the anthraquinones in the regeneration working solution should be adjusted to be the same as the recycling process, or the concentration of the anthraquinones in the recycling process should be higher than the saturation concentration of the anthraquinones . For example: In a working solution containing aromatic hydrocarbons, trioctyl phosphate, ethyl anthraquinone, and ethyl tetrahydroanthraquinone, the total concentration of ethyl anthraquinone and ethyl tetrahydroanthraquinone in the regenerating working solution should be adjusted. It is 0.1 to 1.4 mol / L, preferably 0.3 to 1.2 mol / L, and more preferably 0.5 to 1.0 mol / L.

In the preparation of the crude regeneration working solution, in addition to the components recovered in the distillation step, one or more of aromatic hydrocarbons, trioctyl phosphate and anthraquinones from other supply sources may be mixed. In a specific aspect, aromatic hydrocarbons, trioctyl phosphate, and / or anthraquinones from other sources, including commercially available products or new synthetic products.

In the step of preparing the regenerating working solution for recycling, the crude regenerating working solution obtained in the step of regenerating the working solution is subjected to alkaline washing to prepare a regenerating working solution for recycling. Recycling working solution refers to a regenerating working solution that is particularly suitable for recycling treatment after alkaline washing. The alkaline washing can be performed by washing the crude regeneration working solution with an alkaline aqueous solution or the like. The alkali contained in the alkali aqueous solution is preferably an alkali metal. The alkali metal used for washing may be an alkali metal of Group Ia of the periodic table, and lithium, sodium or potassium is preferred. The reagents containing them are not particularly limited, and examples thereof include lithium hydroxide, sodium hydroxide, sodium carbonate, sodium bicarbonate, sodium borate, sodium diphosphate, sodium boron dioxide, sodium nitrite, sodium trioxide, and sodium hydrogen phosphate. , Sodium silicate, sodium disilicate, sodium trisilicate, sodium stannate, sodium sulfide, sodium thiosulfate, sodium tungstate, potassium hydroxide, potassium borohydride, potassium carbonate, potassium cyanide, potassium nitrite, Potassium phenoxide, potassium hydrogen phosphate, potassium diphosphate, potassium stannate, etc. The components contained in the alkaline aqueous solution are preferably lithium hydroxide, sodium hydroxide, sodium carbonate, sodium bicarbonate, and potassium hydroxide, more preferably sodium hydroxide, sodium carbonate, sodium bicarbonate, and potassium hydroxide, and most preferably hydrogen. Sodium oxide, sodium carbonate, sodium bicarbonate. The pH of the aqueous alkali solution containing an alkali metal is preferably 8 or more, more preferably 10 or more, and even more preferably 12 or more.

The contact between the crude regeneration working solution and the alkaline aqueous solution can be carried out, for example, by contacting an alkaline aqueous solution which is 0.2 times by volume or more with respect to 1 volume part of the crude regeneration working solution. Preferably, the crude regeneration working solution is brought into contact with an alkaline aqueous solution of 0.3 times by volume or more. The contacting method may use generally known mixing means. For example: stirring, shaking, bubbling with inert gas, co-current and AC contact methods, etc., but it is not limited to these, as long as it can contact the crude regeneration working solution with the alkaline aqueous solution with good efficiency. In addition, there is no important upper limit on the capacity of the alkaline aqueous solution to be contacted, and it can be appropriately selected depending on the contacting device and the convenience of operation.

The contact time between the crude regeneration working solution and the alkaline aqueous solution is, for example, more than 1 minute, more preferably 3 minutes or more, and even more preferably 5 minutes or more. It can be appropriately selected depending on the contacting device and convenient operation. The contact temperature of the crude regeneration working solution and the alkaline aqueous solution is, for example, 0 ° C to 70 ° C, preferably 10 ° C to 60 ° C, and particularly preferably 20 ° C to 50 ° C. The pressure in the contact treatment of the crude regeneration working solution and the alkaline aqueous solution is not particularly limited, and it is usually better to keep it at normal pressure. The contacted alkaline aqueous solution is separated from the crude regeneration working solution and discharged. The alkaline washing can be performed more than once, for example: once, twice, or more than three times. By subjecting the regenerating working solution to alkaline washing, the hydrogenation activity of the regenerating working solution can be improved compared to the case of only washing with water. When the crude regeneration working solution contains acidic impurities, it is possible to remove the acidic impurities by washing with an alkali.

In one aspect, in the step of preparing the regenerating working solution for recycling, the water content of the crude regenerating working solution is adjusted to 20% to 160% of the saturated water content. In the hydrogenation step in the hydrogen peroxide production step, the water content of the working solution is preferably about 50% to about 95% of the saturation concentration at the hydrogenation temperature. The crude regeneration working solution prepared from the distillate recovered in the distillation step has a low water content and tends to have a low rate of hydrogenation reaction. Therefore, the recycled regeneration working solution returned to the circulation treatment should preferably have a higher water content than the crude regeneration working solution. The crude regenerating working solution can be washed with an alkaline aqueous solution to increase the water content of the regenerating working solution to the vicinity of the saturated water content. When the alkali cleaning is not within the desired moisture range, the water content can be adjusted by dehydration treatment, additional water, or washing with water.

In the step of preparing the regenerating working solution for recycling, in addition to alkaline washing, washing with water can also be performed. The water used for washing is preferably distilled water, ion-exchanged water, or water obtained by purification by a reverse impregnation method, but water purified by a method other than the above may also be used ideally. Especially, the water used in washing is preferably pure water. Washing with water can be performed in the same manner as alkaline washing, except that water is used as a washing medium. Therefore, the capacity of water relative to the crude regenerating working solution, the contact method with the crude regenerating working solution, the contact time, the contact temperature, the contact pressure, and the like are the same as those for the alkali cleaning. Washing with water can be performed before or after alkaline washing, or both before and after. Washing with water can be performed more than once, for example: once, twice or more than three times.

In the step of preparing the regenerating working solution for recycling, in addition to alkaline washing, the anthraquinones can also be regenerated from byproducts derived from the anthraquinones by using a regeneration catalyst. The treatment using the regeneration catalyst can be carried out by passing the regeneration working solution before or after the alkali cleaning through a fixed bed or a fluidized bed equipped with the regeneration catalyst. Sometimes one pass of the liquid is not enough, so it is better to circulate the liquid. The regeneration catalyst is preferably activated alumina or silica alumina, and activated alumina is more desirable. The surface area and particle diameter of the regeneration catalyst may be appropriately selected depending on the reaction conditions and equipment, but are not particularly limited. The reaction temperature is preferably in the range of 0 ° C to 200 ° C, and more preferably 50 ° C to 150 ° C. In addition, since the reaction proceeds, hydroquinones accumulate and a part of the regeneration reaction progresses, it is suitable to oxidize the hydroquinones by contacting with oxygen or air during the circulation of the liquid. It may be carried out while removing the hydrogen peroxide generated at this time.

In one aspect, the hydrogen peroxide manufacturing method of the present invention includes the step of returning the aforementioned regenerating working solution for recycling to the hydrogen peroxide manufacturing step. The regeneration working solution for recycling can be returned to any one or more of the hydrogenation step, oxidation step, and extraction step included in the hydrogen peroxide production step. Here, returning to a step means any stage from the end of the step before the step to the step before the end of the step. For example, the regenerating working solution for recycling returns to the hydrogenation step, which refers to any stage from the end of the extraction step to the stage before the end of the hydrogenation step (for example: the outlet of the extraction device, the inlet of the hydrogenation device) . In a particular aspect, the regenerating working solution for recycling is returned to the hydrogenation step. In this aspect, it is advantageous to utilize the high hydrogenation activity of the regenerating working solution for recycling. Specific examples of this aspect include mixing a regenerating working solution for circulation with a working solution in a circulation in front of a hydrogenation device (hydrogenation tower), and introducing the obtained mixed solution into the hydrogenation device. In another specific aspect, the recycling regeneration working solution is returned to the oxidation step and / or the extraction step. This aspect is advantageous when the water content of the recycling regeneration working solution is low.

Another aspect of the present invention relates to a method for producing a regenerating working solution for recycling (hereinafter sometimes referred to as the "method for producing a regenerating working solution for recycling"), which has the following steps: Group hydrocarbons, trioctyl phosphate, anthraquinones, and working solutions for the production of hydrogen peroxide, which are inert materials that are by-produced with the generation of hydrogen peroxide, remove the aforementioned inert materials, and prepare crude products from which the inert materials have been removed. Regeneration working solution; and step of preparing a recycling working solution for recycling, subjecting the aforementioned crude regeneration working solution to alkaline washing and preparing a recycling working solution for recycling; the aforementioned working solution regeneration step has: i) a first distillation step at atmospheric pressure or lower Distilling under pressure to recover aromatic hydrocarbons; ii) a second distillation step, and then performing distillation at 160 ° C or higher at a lower pressure to recover anthraquinones and trioctyl phosphate. The characteristics of each step of the method for producing a regenerating working solution for recycling according to the present invention are the same as the corresponding steps in the method for producing a hydrogen peroxide according to the present invention.

Another aspect of the present invention relates to a method for producing hydrogen peroxide (hereinafter sometimes referred to as "the method for producing hydrogen peroxide A of the present invention"), which has the following steps: A step for producing hydrogen peroxide, The working solution of the hydrocarbons, trioctyl phosphate and anthraquinones is hydrogenated and then oxidized to generate hydrogen peroxide. The hydrogen peroxide is extracted from the working solution, and the working solution after the hydrogen peroxide is extracted is returned to the hydrogenation step. And recycle the working solution; the step of regenerating the working solution removes the inert substances that are by-produced with the generation of the hydrogen peroxide from the working solution and prepare a regenerating working solution; and the step of preparing the regenerating working solution for recycling, regenerating the crude regenerating working solution to Wash with water or alkali and prepare a regenerating working solution for recycling; the aforementioned working solution regeneration step has: i) a first distillation step, which is distilled at atmospheric pressure or lower to recover aromatic hydrocarbons; ii) a second distillation step, Distillation at 160 ° C or higher at a lower pressure is then performed to recover anthraquinones and trioctyl phosphate. This aspect is the same except that the alkaline washing of the crude regeneration working solution is not necessary, and it can be replaced by water washing, which is different from the hydrogen peroxide production method of the present invention. As shown in Example 4, even if the crude regenerating working solution is washed with water only, the hydrogenation activity of the regenerating working solution containing trioctyl phosphate is better than the working solution in the cycle. The above description of the hydrogen peroxide production method of the present invention is applicable to the hydrogen peroxide production method A of the present invention under conditions that do not require alkali cleaning.

Another aspect of the present invention relates to a method for producing a regenerating working solution for recycling (hereinafter sometimes referred to as the "method A for producing a regenerating working solution for recycling according to the present invention"), which has the following steps: Aromatic hydrocarbons, trioctyl phosphate, anthraquinones, and a working solution for producing hydrogen peroxide that is an inert substance that is by-produced with the generation of hydrogen peroxide. The inert substance is removed, and the inert substance is prepared. A rough regeneration working solution; and a recycling regeneration working solution preparation step, washing the aforementioned crude regeneration working solution with water or alkali, and preparing a recycling regeneration working solution; the aforementioned working solution regeneration step has: i) a first distillation step, Distilling at atmospheric pressure or lower to recover aromatic hydrocarbons; and ii) a second distillation step, followed by distillation at a lower pressure and above 160 ° C. to recover anthraquinones and trioctyl phosphate. The characteristics of each step of the method A for producing a regenerating working solution for recycling according to the present invention are the same as those of the corresponding steps in the method A for producing a hydrogen peroxide according to the present invention.

Another aspect of the present invention relates to a method for producing hydrogen peroxide (hereinafter sometimes referred to as "the method for producing hydrogen peroxide B of the present invention"), which has the following steps: The step for producing hydrogen peroxide will contain aromatic hydrocarbons The working solution of polar solvents and anthraquinones are hydrogenated and oxidized to generate hydrogen peroxide, the hydrogen peroxide is extracted from the working solution, and the working solution after the hydrogen peroxide is extracted is returned to the hydrogenation step to be circulated; The working solution regeneration step removes the inert substances that are by-produced with the generation of the hydrogen peroxide from the aforementioned working solution and prepares a regenerating working solution; and the step of recycling the regenerating working solution for preparing the crude regeneration working solution by alkaline washing, And a regenerating working solution for recycling is prepared; the aforementioned working solution regeneration step has: i) a first distillation step to perform distillation at atmospheric pressure or lower to recover aromatic hydrocarbons; and ii) a second distillation step, and then at a lower pressure Anthraquinones are recovered by distillation at a temperature below 160 ° C; and the polar solvent is recovered in the first distillation step or the second distillation step. This aspect is the same as the hydrogen peroxide production method of the present invention, except that the polar solvent contained in the working solution is not designated as trioctyl phosphate, and the polar solvent is recovered in the first distillation step or the second distillation step. As shown in Example 4, the crude regenerating working solution was subjected to alkaline washing, which can make the regenerating working solution obtain better hydrogenation activity than washing with water, but it is considered that it contains polar solvents other than trioctyl phosphate So is the working solution. In the above description of the method for producing hydrogen peroxide of the present invention, since the polar solvent is not designated as trioctyl phosphate, the conditions for recovering the polar solvent in either the first distillation step or the second distillation step are also applicable to the present invention. Hydrogen peroxide production method B.

In the hydrogen peroxide production method B of the present invention, the polar solvent is not particularly limited as long as it can dissolve anthrahydroquinones, and includes, for example, alcohols (for example, diisobutyl methanol (DIBC), 2-octanol), and tetra-substituted urea. (For example: tetrabutylurea (TBU)), phosphate (for example: trioctyl phosphate), 2-pyrrolidone or alkylcyclohexyl acetate (for example: methylcyclohexyl acetate (MCHA)) and the like. The distillation step for recovering the polar solvent may be appropriately determined depending on the kind of the polar solvent. For example, DIBC and 2-octanol can be recovered in the first distillation step, and TOP and TBU can be recovered in the second distillation step.

Another aspect of the present invention relates to a method for manufacturing a regenerating working solution for recycling (hereinafter sometimes referred to as "the method B for manufacturing a regenerating working solution for recycling according to the present invention"), which has the following steps: Group hydrocarbons, polar solvents, anthraquinones, and working solutions for the production of hydrogen peroxide that are byproducts of inert materials accompanying the generation of hydrogen peroxide remove the aforementioned inert materials, and prepare crude regeneration working solutions in which the inert materials have been removed; And recycling regeneration working solution preparation step, the aforementioned crude regeneration working solution is subjected to alkaline washing and prepared into a recycling regeneration working solution; the aforementioned working solution regeneration step has: i) a first distillation step under atmospheric pressure or lower pressure Performing distillation to recover aromatic hydrocarbons; and ii) a second distillation step, and then recovering anthraquinones by distillation performed at a lower pressure and above 160 ° C, and the polar solvent is in the first distillation step or the second distillation step Recycle. The characteristics of each step of the method B for producing a regenerating working solution for recycling according to the present invention are the same as those of the corresponding steps in the method B for producing a hydrogen peroxide according to the present invention.

Another aspect of the present invention relates to a hydrogen peroxide production system (hereinafter sometimes referred to as "the hydrogen peroxide production system of the present invention") including a distillation column, a preparation tank, a cleaning tank, a hydrogenation column, an oxidation column, and an extraction column. ). In addition to the above, the hydrogen peroxide production system of the present invention may further include a front-stage distillation distillate tank and / or a post-stage distillation distillate tank. An aspect of the hydrogen peroxide production system of the present invention is described below with reference to the drawings.

FIG. 1 shows the peroxidation of the present invention including a distillation column 1, a preparation tank 2, a washing tank 3, a hydrogenation column 4, an oxidation column 5, an extraction column 6, a front distillation distillate tank 9 and a rear distillation distillate tank 10. Hydrogen manufacturing system A. The distillation column 1 is provided with an unknown component discharge line 8 and a distillate conveying line 7. The distillate conveying line 7 and the previous-stage distillation distillate tank 9 are communicated by the previous-stage distillate conveying line 7 a. The distillate conveying line 7 It communicates with the rear-stage distillation distillate tank 10 by the back-stage distillation distillate conveying line 7b, the front-stage distillation distillate tank 9 and the preparation tank 2 communicate with the front-stage distillation distillate supply line 11, and the back-stage distillation distillate tank 10 It communicates with the preparation tank 2 by the back-end distillation distillate supply line 12, and the preparation tank 2 and the cleaning tank 3 are connected by the crude regeneration working solution supply line 13. The cleaning tank 3 is connected with the alkaline solution supply line 14 and the water supply line 15. The washing tank 3 is provided with a waste liquid line 17. The washing tank 3 and the hydrogenation tower 4 are communicated by a circulating regeneration working solution supply line 16. The hydrogenation tower 4 is provided with a hydrogenation agent supply line 19 and a hydrogenation agent circulation line 18. The hydrogenation tower. 4 and the oxidation tower 5 are connected by a hydrogenated working solution supply line 20, the oxidation tower 5 is provided with an oxidant supply line 21 and an exhaust line 22, the oxidation tower 5 and the extraction tower 6 are connected by an oxidation working solution supply line 23, and the extraction tower 6 is provided Water supply line 24 and hydrogen peroxide delivery line 25 The tower 1 and the extraction tower 6 communicate with each other by using a supply line 26 of the working solution after the hydrogen peroxide is extracted, and the circulating regeneration working solution supply line 16 and the supply line 26 after the hydrogen peroxide is extracted by the hydrogen peroxide solution. The working solution circulation line 27 communicates after the extraction. In addition, the former distillation distillate transportation line 7a, the latter distillation distillate transportation line 7b, the unknown component discharge line 8, the former distillation distillate supply line 11, the latter distillation distillate supply line 12, and the crude regeneration working solution supply line 13. The alkaline solution supply line 14, the water supply line 15, the recycling working solution supply line 16 and the waste liquid line 17 are provided with a valve V. The distillation column 1 can perform vacuum distillation (for example, 0.1 kPa to 15 kPa) at various temperatures (for example, 120 ° C to 260 ° C).

The working solution reacts with a hydrogen-containing hydrogenating agent 32 (such as hydrogen, a mixture of inert gas (nitrogen, etc.) and hydrogen, etc.) from the hydrogenating agent supply line 19 in the hydrogenation tower 4 to generate anthrahydroquinones from anthraquinones. The unreacted hydrogenation agent is repeatedly supplied to the hydrogenation tower 4 through the hydrogenation agent circulation line 18. The hydrogenated working solution enters the oxidation tower 5 through the hydrogenated working solution supply line 20, and the anthrahydroquinones are oxidized by the oxygen-containing oxidant 33 (for example, air, oxygen, etc.) sent to the oxidant supply line 21 to generate anthraquinone Class with hydrogen peroxide. The unreacted oxidant 34 is exhausted from the exhaust line 22. The oxidized working solution containing hydrogen peroxide enters the extraction tower 6 through the oxidizing working solution supply line 23, and the generated hydrogen peroxide is in the form of hydrogen peroxide water 36 through the water 35 supplied from the water supply line 24 Recovered from the hydrogen peroxide transport line 25. Part of the working solution after the extraction of hydrogen peroxide enters the distillation column 1 through the supply line 26 of the working solution after the extraction of hydrogen peroxide, and the rest passes through the working solution circulation line 27 after the extraction of hydrogen peroxide, which is condensed in the recycling regeneration The working solution is supplied to the line 16 and returned to the hydrogenation tower 4.

The working solution after the hydrogen peroxide having entered the distillation column 1 is extracted and supplied to the previous stage distillation at atmospheric pressure or lower. The aromatic distillate-containing pre-distillate distillate which is distilled from the first-stage distillation is stored in the first-stage distillate distillate tank 9 through the distillate conveying line 7 and the first-stage distillate conveying line 7a. The residue remaining in the distillation column 1 is provided for the subsequent distillation at a lower pressure and at a temperature of 160 ° C. or higher than that of the previous distillation. Distillate containing anthraquinones and trioctyl phosphate, which is distilled in the latter stage, is contained in the subsequent stage distillate tank 10 through the distillate transport line 7 and the latter stage distillate transport line 7b. The unknown component 28 which is the residue after the distillation in the latter stage is discharged from the unknown component discharge line 8. The distillate stored in the front stage of the distillate tank 9 and the distillate stored in the back stage of the distillate tank 10 are passed through the front stage distillate supply line 11 and the rear stage distillate supply line. 12 and enter the preparation tank 2 and mix to prepare a crude regeneration working solution. The prepared crude regeneration working solution enters the washing tank 3 through the crude regeneration working solution supply line 13. The crude regeneration working solution is washed with the alkali solution 29 supplied from the alkali solution supply line 14 and then further washed with water 30 supplied from the water supply line 15 as necessary to become a recycling regeneration working solution. The alkaline solution or water used for washing is discharged from the waste liquid line 17 as the waste liquid 31. The regenerating working solution for circulation passes through the regenerating working solution supply line 16 for circulation, and the working solution from the working solution circulation line 27 after the hydrogen peroxide is extracted converges and enters the hydrogenation tower 4.

The hydrogen peroxide production system of the present invention may further include a recrystallization tank. The outline of the hydrogen peroxide production system B of the present invention including a recrystallization tank will be described with reference to FIG. 2. In the hydrogen peroxide production system B, the same components as those of the hydrogen peroxide production system A shown in FIG. 1 are denoted by the same reference numerals, and descriptions thereof are omitted.

In this aspect, the distillate supply line 12 connected to the rear stage distillate tank 10 is connected to the recrystallization tank 37, and the anthraquinone supply line 40 connected to the recrystallization tank 37 is connected to the preparation tank 2. The recrystallization tank 37 is further connected with a recrystallization solvent supply line 39, a waste liquid line 41, and a filtrate transportation line 42. The recrystallization solvent supply line 39 connects the recrystallization solvent tank 38 and the recrystallization tank 37, and the filtrate transportation line 42 will recrystallize The tank 37 communicates with the distillation column 1. The recrystallization solvent tank 38 communicates with the distillate recrystallization solvent transport line 7d and the distillate transport line 7, and the preparation tank 2 communicates with the distillate TOP transport line 7c and the distillate transport line 7. The recrystallization tank 37 is provided with a temperature adjustment device, and can heat and dissolve anthraquinones in a recrystallization solvent and cool them after use to recrystallize the anthraquinones. The recrystallization tank 37 is further equipped with a filter for separating and filtering the recrystallized anthraquinones.

In this aspect, the latter distillation distillate accommodated in the latter distillation distillate tank 10 passes through the latter distillation distillate supply line 12 and enters the recrystallization tank 37. In the recrystallization tank 37, a recrystallization solvent is supplied from a recrystallization solvent supply line 39, the anthraquinones are heated and dissolved, and then cooled to recrystallize the anthraquinones contained in the subsequent distillation distillate. The recrystallized anthraquinones are recovered by a filter provided in the recrystallization tank 37 and sent to the preparation tank 2 through the anthraquinone supply line 40. The filtrate containing trioctyl phosphate and the recrystallization solvent that has passed through the filter is sent to the distillation column 1 through the filtrate transfer line 42 or discarded from the waste liquid line 41. The recrystallization solvent and trioctyl phosphate are distilled from the filtrate sent to the distillation column 1 by distillation, and the distilled recrystallization solvent is contained in the recrystallization through the distillate conveying line 7 and the distilling recrystallization solvent conveying line 7d. The solvent tank 38 and the distilled trioctyl phosphate are sent to the preparation tank 2 through the distillate conveying line 7 and the distilled TOP conveying line 7c.

The hydrogen peroxide production system of the present invention is not limited to the aspect described above, and various changes can be made within the scope of the gist of the present invention. For example: In the hydrogen peroxide manufacturing system A shown in FIG. 1, (A1) does not provide a front-stage distillation distillate tank 9 and a front-stage distillation distillate conveying line 7a connected to it, but separates the distillate conveying line 7 and the preparation The tank 2 is connected by a front-stage distillate supply line 11 and (A2) the back-stage distillate tank 10 and the back-stage distillate transport line 7b connected thereto are not provided, and the distillate transport line 7 and the preparation tank are connected (2) It is connected by the rear-stage distillation distillate supply line 12, (A3) The front-stage distillation distillate tank 9 and the front-stage distillation distillate conveying line 7a, the back-stage distillation distillate tank 10, and the rear stage connected to it are not provided. The distillate conveying line 7b, and the distillate conveying line 7 and the preparation tank 2 are communicated with the former distillation distillate supply line 11 and the latter distillation distillate supply line 12, and (A4) no distillate conveyance is provided. Line 7, the former distillation distillate tank 9 and the former distillation distillate conveying line 7a, the latter distillation distillate tank 10, and the latter distillation distillate conveying line 7b connected to it. Instead, the distillation column 1 and The preparation tank 2 utilizes the first stage distillate supply line 11 and the second stage distillate. The supply line 12 is connected.

In addition, in the hydrogen peroxide production system B shown in FIG. 2, in addition to the above-mentioned changes (A1) to (A4) for the hydrogen peroxide production system A, for example, (B1) the filtrate transport line 42 and the distillation are not provided. The recrystallization solvent conveying line 7d and (B2) are provided with a distillate TOP tank, and the distillate conveying line 7 and the distillate TOP tank are communicated by the distillate TOP conveying line 7c, and the distillate TOP tank and the preparation tank 2 are used. The distillate TOP supply line is communicated, (B3) is not provided in the recrystallization tank 37, and is provided in the middle of the anthraquinone supply line 40, and the like. In addition, in either of the hydrogen peroxide production systems A and B, a pump, an additional valve, a branch line, or a valve may be taken from a line provided with a valve, if necessary, in at least one of the lines.

The following describes the present invention in more detail with examples, but the present invention is not limited thereto. [Example]

<Analytical method> A gas chromatography analysis device was used to quantify the aromatic hydrocarbons, trioctyl phosphate, 2-ethylanthraquinone, and 2-ethyltetrahydroanthraquinone in the working solution and the samples obtained by each operation. As the gas chromatography analysis device, gas chromatography GC-2014 manufactured by Shimadzu Corporation was used. As the column, a capillary column DB-5MS manufactured by Agilent was used. In addition, all substances other than the above-mentioned components are described as "unknown components." The "unknown ingredient" is mostly assumed to be an inert substance.

The density of the initial working solution and the regenerating working solution for recycling was measured using a density densitometer DA-640 manufactured by Kyoto Electronics Industry Corporation, and the viscosity was measured using a B-type viscometer manufactured by Tokyo Keiki Co., Ltd. The hydrogenation activities of the initial working solution and the regenerating working solution for recycling were evaluated by the following methods. A 100 mL 2-necked flask was charged with a hydrogenation catalyst and a working solution. One end of the flask was connected to a stirrer, and the other end was connected to a hydrogen supply unit. The flask was hermetically sealed. The hydrogen supply unit is composed of a hydrogen metering tube, a U-shaped barometer, and a water storage section. The height of the water storage section is adjusted by cooperating with the liquid level change of the U-shaped barometer in the hydrogenation reaction to maintain the internal pressure of the flask Equal to atmospheric pressure. The amount of hydrogen absorption is measured as the difference in height of the liquid level in the hydrogen metering tube. The flask was immersed in a water bath at 30 ° C and left to stand for 10 minutes. After the exhaust gas and hydrogen introduction in the flask were repeated three times, the stirrer was operated. The hydrogen absorption amount was measured until 30 minutes after the start of hydrogen absorption. The amount of hydrogen absorption is converted to 1 atm at 0 ° C. The activity of hydrogenation catalyst is expressed in the standard state hydrogen absorption rate [NmL / (min × g)] per unit weight of hydrogenation catalyst. For the hydrogenation catalyst, 0.05 g of 2% by weight Pd / silica dioxide dried at 120 ° C or 0.1 g of 1% by weight Pd / silica dioxide dried at 120 ° C was used.

Example 1 The first distillation step and the second distillation step in the present invention were carried out on a small scale, and the initial working solution and the regenerating working solution for recycling were compared. <First Distillation Step> A 500 mL flask provided in a distillation apparatus was charged with 400 g of a working solution. Distillation under reduced pressure, the vacuum degree is always controlled at 1.3kPa. The temperature in the flask was raised from room temperature to 182 ° C. Distillation was continued until it was no longer distilled under the conditions of 1.3 kPa and 182 ° C. <Second distillation step> The residue obtained in the first distillation step is distilled at a lower pressure than that in the first distillation step. The vacuum degree temporarily changed from 0.03kPa to 0.15kPa from the beginning of the distillation, but finally settled at 0.08kPa. The temperature in the flask was raised from room temperature to 202 ° C. Continue distillation until it is no longer distilled at 0.08kPa, 202 ° C. <Distillation results> Table 1 shows the composition of the initial working solution, the distillate and the residue recovered by each distillation step. As the aromatic hydrocarbon system, a high-boiling-point aromatic petroleum brain (SWASOL1500, manufactured by Maruzan Petrochemical Co., Ltd., CAS No. 64742-94-5) was used (the same applies to Examples 2 to 4). In addition, various reactions such as conversion of tetrahydroanthraquinone to anthraquinone mainly occur during distillation. Therefore, depending on the components, the weight may increase more than the initial working solution. In addition, the "loss component" represents the amount of loss in the experiment (the reason is considered to be a loss to a cold trap, a pump, etc.).

[Table 1] Composition of initial working solution, distillate and residue (substance balance)

<Evaluation of Recycling Working Solution for Recycling> A regenerating working solution was prepared from the distillate recovered in each distillation step. The fraction of the first distillation step was added to the fraction of the second distillation step so as to become a solvent composition ratio close to the initial working solution as a crude regeneration working solution. The composition of the initial working solution and the crude regeneration working solution is disclosed below. [Table 2] Composition of initial working solution and crude regeneration working solution

The crude regeneration working solution was sequentially washed with a double volume volume of a 30 wt% sodium hydroxide aqueous solution and a double volume volume of pure water as a recycling regeneration working solution. The density, viscosity, and hydrogenation activity of the initial working solution and the recycled regeneration working solution were compared, and the results are shown below. When evaluating hydrogenation activity, 0.05 g of 2% by weight Pd / silicon dioxide dried at 120 ° C was used as a hydrogenation catalyst. [Table 3] Comparison of initial working solution and recycling working solution

<Separation of anthraquinones> About 32 mL of ethanol was added to 32 g of the distillate in the second distillation step, and the mixture was heated to dissolve and cooled to room temperature (recrystallization). The crystals were separated by filtration and dried. The composition of the distillate from the second distillation step and the crystals recovered from the recrystallization will be described below. Anthraquinones can be separated from trioctyl phosphate and unknown components with a recovery rate of 64%. In this method, the recovered anthraquinones can be reused as a component of a working solution. [Table 4] Composition of distillate from the second distillation step and crystals recovered from recrystallization

Example 2 In the present invention, the first distillation step and the second distillation step were performed under different conditions from those in Example 1, and the initial working solution and the regenerating working solution for recycling were compared. <First Distillation Step> A 500 mL flask provided in a distillation apparatus was charged with 351 g of a working solution. Distillation under reduced pressure, the vacuum degree is always controlled at 1.3kPa. The temperature in the flask was raised from room temperature to 157 ° C. Continue to distill until the final distillation at 1.3kPa, 157 ° C. <Second distillation step> The residue obtained in the first distillation step is distilled at a lower pressure than that in the first distillation step. The vacuum degree temporarily changed between 10Pa ~ 150Pa at the beginning of distillation, but finally settled at 0.01kPa ~ 0.04kPa. The temperature in the flask was raised from room temperature to 181 ° C. Continue distillation until it is no longer distilled under the conditions of 0.01 kPa and 181 ° C. <Distillation results> Table 5 shows the composition of the initial working solution, the distillate and the residue recovered by each distillation step.

[Table 5] Composition of initial working solution, distillate and residue (substance balance)

In the same manner as in Example 1, a crude regeneration working solution was prepared. Table 6 reveals the composition of the initial working solution and the crude regenerating working solution. [Table 6] Composition of initial working solution and crude regeneration working solution

Following the same washing procedure as in Example 1, a regenerating working solution for recycling was prepared. Table 7 reveals the comparison of the density, viscosity, and hydrogenation activity of the initial working solution and the regenerating working solution for recycling. When evaluating hydrogenation activity, 0.1 g of Pd / silica alumina, dried at 120 ° C, was used as a hydrogenation catalyst. [Table 7] Comparison of initial working solution and recycling working solution for recycling

Example 3 The first distillation step and the second distillation step in the present invention were performed under conditions different from those in Examples 1 and 2, and the initial working solution and the regenerating working solution for recycling were compared. <First Distillation Step> A 500 mL flask provided in a distillation apparatus was charged with 351 g of a working solution in the same manner as in Example 2. Distillation under reduced pressure, the vacuum degree is always controlled at 1.3kPa. The temperature in the flask was raised from room temperature to 180 ° C. Continue distillation until it is no longer distilled at 1.3 kPa and 180 ° C. <Second distillation step> The residue obtained in the first distillation step is distilled at a lower pressure than that in the first distillation step. The degree of vacuum is always controlled at 0.13kPa. The temperature in the flask was raised from room temperature to 250 ° C. Continue distillation until it is no longer distilled under the conditions of 0.13 kPa and 250 ° C. <Distillation results> Table 8 shows the composition of the initial working solution, the distillate and the residue recovered by each distillation step.

[Table 8] Composition of initial working solution, distillate and residue (substance balance)

A crude regeneration working solution was prepared in the same manner as in Example 1. Table 9 reveals the composition of the initial working solution and the crude regenerating working solution. [Table 9] Composition of initial working solution and crude regeneration working solution

Following the same washing procedure as in Example 1, a regenerating working solution for recycling was prepared. Table 10 reveals a comparison of density, viscosity, and hydrogenation activity. When evaluating hydrogenation activity, 0.1 g of Pd / silica alumina, dried at 120 ° C, was used as a hydrogenation catalyst. [Table 10] Evaluation of initial working solution and recycling working solution for recycling

Example 4 The crude regenerating working solution prepared in Example 2 was washed twice with twice the volume of pure water as a regenerating working solution for circulation (purified water washing). A hydrogenation activity test was performed in the same manner as in Example 2. As the hydrogenation catalyst, 0.1 g of 1% by weight Pd / silica alumina dried at 120 ° C was used. Table 11 shows the results of the hydrogenation activity test. The regenerative working solution of the recycling regeneration solution subjected to pure water washing only has a higher hydrogenation activity than the initial working solution, but the hydrogenation activity of the regenerating working solution of the recycling regeneration solution (Example 2) washed with alkali is higher. [Table 11] Hydrogenation activity

1‧‧‧ distillation tower

2‧‧‧ Preparation tank

3‧‧‧washing tank

4‧‧‧ hydrogenation tower

5‧‧‧ oxidation tower

6‧‧‧extraction tower

7‧‧‧ Distillate Conveying Line

7a‧‧‧ Forefront Distillate Distillate Conveying Line

7b‧‧‧ post-distillate distillate conveying line

7c‧‧‧Distillation TOP Conveying Line

7d‧‧‧Distillation recrystallization solvent delivery line

8‧‧‧Unknown ingredient discharge line

9‧‧‧ Fore-stage distillation distillate tank

10‧‧‧ Post-distillation distillate tank

11‧‧‧ Forefront Distillate Distillate Supply Line

12‧‧‧ post-distillate distillate supply line

13‧‧‧ crude regeneration working solution supply line

14‧‧‧ Alkaline solution supply line

15‧‧‧Water supply line

16‧‧‧Recycling working solution supply line

17‧‧‧ Waste liquid line

18‧‧‧ Hydrogenating agent circulation line

19‧‧‧ Hydrogenating agent supply line

20‧‧‧ Hydrogenated working solution supply line

21‧‧‧Oxidant supply line

22‧‧‧Exhaust line

23‧‧‧ Oxidation working solution supply line

24‧‧‧Water supply line

25‧‧‧Hydrogen peroxide transportation line

26‧‧‧ Supply line of working solution after hydrogen peroxide is extracted

27‧‧‧Circulation line of working solution after hydrogen peroxide is extracted

28‧‧‧ unknown

29‧‧‧ alkaline solution

30‧‧‧ water

31‧‧‧waste liquid

32‧‧‧ hydrogenation agent

33‧‧‧Oxidant

34‧‧‧ Unreacted oxidant

35‧‧‧ water

36‧‧‧ Hydrogen peroxide water

37‧‧‧ recrystallization tank

38‧‧‧ recrystallization solvent tank

39‧‧‧Recrystallization solvent supply line

40‧‧‧Anthraquinone Supply Line

41‧‧‧waste liquid line

42‧‧‧ filtrate transfer line

V‧‧‧ Valve

FIG. 1 is a schematic diagram of an aspect of a hydrogen peroxide production system of the present invention. FIG. 2 is a schematic diagram of an aspect of the hydrogen peroxide production system of the present invention provided with a recrystallization tank.

Claims (16)

A method for producing hydrogen peroxide, which is characterized in that it includes the following steps: The step for producing hydrogen peroxide is to hydrogenate a working solution containing aromatic hydrocarbons, trioctyl phosphate, and anthraquinones and oxidize them to generate hydrogen peroxide. Extracting the hydrogen peroxide from the working solution, so that the working solution after the hydrogen peroxide has been extracted is returned to the hydrogenation step to be circulated; the working solution regeneration step, from the working solution will be accompanied by the generation of the hydrogen peroxide and vice versa. The raw inert substance is removed, and a crude regeneration working solution from which the inert substance has been removed is prepared; and a step of preparing a recycling regeneration working solution for recycling, the crude regeneration working solution is subjected to alkaline washing, and a recycling regeneration working solution is prepared; the working solution The regeneration step has the following steps: i) a first distillation step, which uses aromatic distillation at atmospheric pressure or lower to recover aromatic hydrocarbons; and ii) a second distillation step, which is performed at a lower pressure and above 160 ° C Distillation to recover anthraquinones and trioctyl phosphate. For example, the method for producing hydrogen peroxide according to item 1 of the patent application range, wherein the pressure in the first distillation step is in the range of 1 kPa to 100 kPa. For example, the method for producing hydrogen peroxide in the first or second scope of the patent application, wherein the pressure in the second distillation step is 1 kPa or less. For example, the method for producing hydrogen peroxide according to any one of claims 1 to 3, wherein the temperature in the second distillation step is in the range of 160 ° C to 300 ° C. For example, the method for producing hydrogen peroxide according to any one of claims 1 to 4, wherein the anthraquinones include alkylanthraquinone and alkyltetrahydroanthraquinone. For example, the method for producing hydrogen peroxide according to any one of claims 1 to 5 includes a step of returning the recycling working solution for recycling to the step of producing hydrogen peroxide. For example, the manufacturing method of hydrogen peroxide according to item 6 of the patent application, wherein the solvent composition ratio of the crude regeneration working solution is within a range of ± 20% relative to the solvent composition ratio of the working solution circulated in the hydrogen peroxide manufacturing step. . For example, the manufacturing method of hydrogen peroxide in the scope of patent application item 6 or 7, wherein the concentration of anthraquinones in the crude regeneration working solution is the concentration of anthraquinones in the working solution circulated in the hydrogen peroxide manufacturing step. Above and below the saturated concentration of anthraquinones. For example, in the manufacturing method of hydrogen peroxide according to any one of claims 6 to 8, in the step of preparing the regenerating working solution for recycling, the regenerating working solution is adjusted to 20% to 160% of the saturated water content. For example, the method for manufacturing hydrogen peroxide according to any one of claims 6 to 9, wherein the step of preparing the regenerating working solution for recycling further includes a step of washing the regenerating working solution after washing with alkali. For example, the method for producing hydrogen peroxide according to any one of claims 1 to 10 of the patent application scope further includes a step of separating anthraquinones and trioctyl phosphate from the distillate of the second distillation step. For example, the method for producing hydrogen peroxide according to item 11 of the application, wherein the step of separating the anthraquinones from trioctyl phosphate is performed by recrystallization. A hydrogen peroxide manufacturing system comprising a distillation tower, a preparation tank, a cleaning tank, a hydrogenation tower, an oxidation tower, and an extraction tower; the distillation tower includes an unknown component discharge line; the distillation tower and the preparation tank use a front-stage distillation distillate supply line; and The subsequent distillation distillate supply line is used to communicate. The preparation tank and the cleaning tank are connected by using the crude regeneration working solution supply line. The cleaning tank is connected to the alkaline solution supply line and the water supply line. The cleaning tank is equipped with a waste liquid line. The tank and the hydrogenation tower are connected by a circulating regeneration working solution supply line, the hydrogenation tower is connected with a hydrogenation agent supply line, the hydrogenation tower and the oxidation tower are connected by a hydrogenation working solution supply line, the oxidation tower is connected with an oxidant supply line, and the oxidation tower and extraction The tower is connected by an oxidizing working solution supply line, the extraction tower is provided with a hydrogen peroxide delivery line, and the distillation tower and the extraction tower are connected by a supply line of the working solution after the hydrogen peroxide is extracted. For example, the hydrogen peroxide manufacturing system in the scope of application for patent No. 13 further includes a front-stage distillation distillate tank. The distillation tower and the front-stage distillation distillate tank are connected by a front-stage distillation distillate conveying line. The preparation tank is communicated by a front-stage distillation distillate supply line. For example, the hydrogen peroxide manufacturing system in the 13th scope of the patent application has a rear-stage distillation distillate tank. The distillation tower and the rear-stage distillation distillate tank are connected by a back-stage distillation distillate conveying line. The preparation tank is communicated by a rear-stage distillation distillate supply line. For example, the hydrogen peroxide manufacturing system in the 13th scope of the patent application has a recrystallization tank. The recrystallization tank is equipped with a filter and a waste liquid line. The recrystallization tank is connected to the recrystallization solvent supply line. The recrystallization tank and the distillation tower use the latter stage of distillation. The distillate supply line is connected, and the recrystallization tank and the preparation tank are connected by an anthraquinone-based supply line.