TWI770262B - Manufacturing method of hydrogen peroxide - Google Patents

Abstract

The present invention provides a method for removing inert substances from a working solution containing trioctyl phosphate (TOP) and obtaining a high-quality regenerated working solution. A method for producing hydrogen peroxide, comprising the following steps: a step for producing hydrogen peroxide, wherein a working solution containing aromatic hydrocarbons, TOP, and anthraquinones is hydrogenated and then oxidized to generate hydrogen peroxide and remove it from the working solution Extraction is carried out, and the working solution after the hydrogen peroxide is extracted is returned to the hydrogenation step to make it circulate; the working solution regeneration step is to remove the by-produced inert substances from the working solution along with the generation of hydrogen peroxide and prepare a crude regeneration working solution, The crude regenerated working solution is subjected to alkaline washing, and a regenerated working solution for recycling is prepared; the working solution regeneration step has the following steps: i) a first distillation step, which is distilled at atmospheric pressure or lower to recover aromatic hydrocarbons; and ii ) The second distillation step, and then distillation at a lower pressure above 160° C. to recover anthraquinones and TOP.

Description

Manufacturing method of hydrogen peroxide

The present invention relates to a method for producing hydrogen peroxide using anthraquinones, in particular, 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, so it is used as a bleaching agent, bactericide, etc. for paper, wood pulp, fiber, and the like. The decomposition products of hydrogen peroxide are water and oxygen, so from the viewpoint of environmental protection, it is placed in an important position, especially as a substitute material for chlorine-based bleaching agents. Furthermore, in the semiconductor industry such as surface cleaning of semiconductor substrates, chemical polishing of surfaces of copper, tin and other copper alloys, and etching of electronic circuits, the usage of hydrogen peroxide has also increased. In addition, hydrogen peroxide is widely used in oxidation reactions such as epoxidation and hydroxylation, and is an important industrial product.

An anthraquinone method is known as an industrial method for producing hydrogen peroxide. In this method, anthraquinones are dissolved in an organic solvent to obtain a working solution, and 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 hydrogen peroxide is generated at the same time. The 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 recycle process is formed.

In the process of repeating the operations of hydrogenating anthraquinones contained in the working solution to anthrahydroquinones and oxidizing them to anthraquinones to produce hydrogen peroxide, tetrahydroanthracene which does not contribute to the generation of hydrogen peroxide is generated Quinone epoxide, tetraoxonone, oxyallone, allionone and other anthraquinone monomer by-products, anthraquinone solvent adducts and anthraquinone polymers, etc. In addition, a deteriorated product of the solvent component is also generated. Such ingredients not involved in the manufacture of hydrogen peroxide are classified as "inert substances". The increase of this inert material may cause a decrease in the concentration of the active material, ie, anthraquinones, etc., and may reduce the ability of each step of the cyclic treatment. Therefore, it is necessary to have a working solution in which the concentration of the inert substance is low and the concentration of the active substance is kept sufficiently high (Patent Document 1). [Prior Art Literature] [Patent Literature]

[Patent Document 1] WO2007/129769

(The problem 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 containing an aromatic hydrocarbon as a non-polar solvent, ginseng (2-ethylhexyl) phosphate (CAS number: 78-42-2, sometimes described below). It is "Trioctyl Phosphate" or "TOP") as a polar solvent, and alkyl anthraquinone and alkyl tetrahydroanthraquinone are used as the working solution of anthraquinones. However, there has not yet been a method for suppressing the concentration of an inert substance in a working solution containing trioctyl phosphate as a polar solvent and maintaining a sufficiently high concentration of an active substance. Therefore, an object of the present invention is to provide a method for removing inert substances from a working solution containing trioctyl phosphate used in the production of hydrogen peroxide by anthraquinone method, and maintaining or improving the physical properties and/or activity of the working solution. (the way to solve the problem)

The inventors of the present invention have made diligent studies in order to solve the above-mentioned problems, and as a result, have found a method for removing by-products from a working solution containing aromatic hydrocarbons, trioctyl phosphate, and anthraquinones. This method uses distillation under atmospheric pressure or lower to recover aromatic hydrocarbons, and then under lower pressure above 160°C to recover anthraquinones and trioctyl phosphate, and distills all the recovered distillates. Reuse as working solution. In addition, the inventors of the present invention have further studied and found that the hydrogenation activity can be improved by alkali cleaning of the regenerated working solution.

One aspect of the present invention is as follows. [1] A method for producing hydrogen peroxide, comprising the following steps: a hydrogen peroxide production step, wherein a working solution containing aromatic hydrocarbons, trioctyl phosphate and anthraquinones is hydrogenated and then oxidized to generate Hydrogen peroxide, extracting the hydrogen peroxide from the working solution, returning the working solution after the hydrogen peroxide has been extracted to the hydrogenation step to circulate it; working solution regeneration step, from which the working solution will accompany the hydrogen peroxide; The generated and by-produced inert substances are removed, and a crude regeneration working solution from which the inert substances have been removed is prepared; and the step of preparing a regeneration working solution for recycling is to perform alkaline cleaning on the crude regeneration working solution, and a regeneration working solution for recycling is prepared; The working solution regeneration step has the following steps: i) a 1st distillation step utilizing distillation performed at atmospheric pressure or lower to recover aromatic hydrocarbons; and ii) a 2nd distillation step utilizing next lower pressure and 160 ℃ above the distillation 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 the 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 the 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 contain an alkylanthraquinone and an alkyltetrahydroanthraquinone. [6] The method for producing hydrogen peroxide according to any one of [1] to [5], comprising the step of returning the regenerated 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 regeneration working solution is within the range of ±20% with respect 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 the anthraquinones in the working solution circulated in the hydrogen peroxide production step within the range above the concentration of anthraquinones and below the saturation concentration of anthraquinones. [9] The method for producing hydrogen peroxide according to any one of [6] to [8], wherein, in the step of preparing the regeneration working solution for circulation, the regeneration working solution is adjusted to be 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 regeneration working solution for circulation further comprises a step of washing the regeneration working solution after alkali washing with water. [11] The method for producing hydrogen peroxide according to any one of [1] to [10], further comprising a step of separating anthraquinones and trioctyl phosphate from the distillate of the second distillation step. [12] The method for producing hydrogen peroxide according to [11], wherein the step of separating the anthraquinones and trioctyl phosphate is performed by recrystallization.

[13] A hydrogen peroxide production system, comprising a distillation column, a preparation tank, a washing tank, a hydrogenation column, an oxidation column, and an extraction column, the distillation column is provided with an unidentified component discharge line, and the distillation column and the preparation tank are supplied with a front-stage distillation distillate line and the second-stage distillation distillate supply line, the preparation tank and the washing tank are connected by the crude regeneration working solution supply line, the washing tank is connected with the alkaline solution supply line and the water supply line, and the washing tank is equipped with a waste liquid line , the cleaning tank and the hydrogenation tower are connected by the supply line of the regenerating working solution for circulation, the hydrogenation tower is connected with the hydrogenation agent supply line, the hydrogenation tower and the oxidation tower are connected by the supply line of the hydrogenation working solution, the oxidation tower is connected with the oxidant supply line, and the oxidation The tower and the extraction tower are communicated with the oxidation working solution supply line, the extraction tower is provided with a hydrogen peroxide conveying line, and the distillation tower and the extraction tower are communicated with the supply line of the working solution after the hydrogen peroxide is extracted. [14] The hydrogen peroxide production system according to [13], further comprising a front-stage distillation distillate tank, the distillation column and the front-stage distillation distillate tank are connected by a front-stage distillation distillate conveying line, and the front-stage distillation distillate tank is connected to The preparation tank is communicated with the pre-stage distillation distillate supply line. [15] The hydrogen peroxide production system according to [13], further comprising a back-stage distillation distillate tank, the distillation column and the back-stage distillation distillate tank are communicated with the back-stage distillation distillate conveying line, and the back-stage distillation distillate tank is connected to The preparation tank is communicated with the back-stage distillation distillate supply line. [16] The hydrogen peroxide production system according to [13], further comprising a recrystallization tank, the recrystallization tank is provided with a filter and a waste liquid line, the recrystallization tank is connected to a recrystallization solvent supply line, and the recrystallization tank and the distillation tower utilize post-stage distillation The distillate supply line is connected, and the recrystallization tank and the preparation tank are connected by an anthraquinone supply line. (effect of invention)

The present invention exhibits one or more of the following effects. (1) The inert substance can be removed from the working solution containing trioctyl phosphate as a polar solvent in which the inert substance has accumulated. (2) Anthraquinones, which are active substances, can be efficiently recovered and reused from a working solution containing trioctyl phosphate as a polar solvent. (3) By reducing the inert substances in the circulating working solution, each step of hydrogen peroxide production can be maintained in a state of high efficiency. (4) The viscosity of the circulating working solution can be kept low. (5) The hydrogenation activity of the circulating working solution can be maintained in a high state. (6) It can be used in a working solution containing trioctyl phosphate that is frequently used, so it has a wide range of applications and 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 of the present invention"). Hydrogen peroxide, trioctyl phosphate, and anthraquinone working solutions are hydrogenated (reduced) and then oxidized to generate hydrogen peroxide, the hydrogen peroxide is extracted from the working solution, and the working solution after the hydrogen peroxide has been extracted Return to the hydrogenation step and make it circulated; a working solution regeneration step, from which inert substances by-produced with the generation of the hydrogen peroxide are removed from the working solution, and a crude regeneration working solution from which the inert substances have been removed is prepared; The regeneration working solution preparation step, the crude regeneration working solution is washed with alkali, and the regeneration working solution for recycling is prepared; The working solution regeneration step has the following steps: i) The first distillation step, which is carried out at atmospheric pressure or lower pressure and ii) a second distillation step, followed by distillation at lower pressure and above 160°C to recover anthraquinones 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: containing 9 carbon atoms) Atoms of trimethylbenzene, etc.) or mixtures thereof, preferably those that can dissolve anthraquinone. In a specific aspect, the aromatic hydrocarbon is selected from a mixed solvent of carbon number 10 and a mixed solvent of carbon number 9 (eg, a mixture of cumene isomers). Trioctyl phosphate, which is a polar solvent, is a compound having the following structure. 【Change 1】

The anthraquinones contained in the working solution include at least one of anthraquinone (9,10-anthraquinone), tetrahydroanthraquinone and derivatives thereof, which can generate hydrogen peroxide by the anthraquinone method. The derivative of anthraquinone capable of generating hydrogen peroxide is not limited, for example, alkyl anthraquinone. Alkyl anthraquinone refers to an anthraquinone substituted with at least one alkyl group. In a specific aspect, alkyl anthraquinones include anthraquinones that are at least one substituted at the 1, 2 or 3 positions by a straight or branched chain aliphatic substituent containing at least 1 carbon atom. The alkyl substituent in the alkylanthraquinone preferably contains 1 to 9, more preferably 1 to 6 carbon atoms. Specific examples of alkyl anthraquinone are not limited, for example: methyl anthraquinone (2-methyl anthraquinone, etc.), dimethyl anthraquinone (1,3-, 2,3-, 1,4-, 2, 7-dimethyl anthraquinone, etc.), ethyl anthraquinone (2-ethyl anthraquinone, etc.), propyl anthraquinone (2-n-propyl anthraquinone, 2-isopropyl anthraquinone, etc.), butyl anthraquinone Quinones (2-second butyl anthraquinone, 2-tert-butyl anthraquinone, etc.), pentyl anthraquinone (2-second pentyl anthraquinone, 2-third pentyl anthraquinone, etc.) and the like. Desirable alkyl anthraquinones can be exemplified by ethyl anthraquinone, amyl anthraquinone, or mixtures thereof. The concentration of alkyl anthraquinones in the working solution can be controlled according to the treatment conditions, for example, it is used in the concentration range of 0.4~1.0mol/L.

The derivative of tetrahydroanthraquinone capable of generating hydrogen peroxide is not limited, for example, alkyl tetrahydroanthraquinone. Alkyl tetrahydroanthraquinone refers to a tetrahydroanthraquinone substituted with at least one alkyl group. In particular aspects, alkyl tetrahydroanthraquinones include tetrahydroanthraquinones at least one substituted for the 1, 2 or 3 positions by a straight 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 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-propyltetrahydroanthraquinone, etc.) Hydroanthraquinone, 2-isopropyltetrahydroanthraquinone, etc.), butyltetrahydroanthraquinone (2-second-butyltetrahydroanthraquinone, 2-tert-butyltetrahydroanthraquinone, etc.), pentyltetrahydroanthraquinone Hydroanthraquinone (2-second amyltetrahydroanthraquinone, 2-third amyltetrahydroanthraquinone, etc.) and the like. Desirable alkyltetrahydroanthraquinones include ethyltetrahydroanthraquinone, pentyltetrahydroanthraquinone, or mixtures thereof.

In one aspect, the working solution includes a combination of an alkyl anthraquinone and an alkyl tetrahydroanthraquinone. In this combination, the molar ratio of alkyl anthraquinone to alkyl tetrahydroanthraquinone is not particularly limited, and alkyl anthraquinone: alkyl tetrahydroanthraquinone is preferably 0.05:1~100:1, preferably 0.1:1~ 75:1 is better, 0.2:1~50:1 is better. In addition, the weight ratio of alkyl anthraquinone to alkyl tetrahydroanthraquinone is not particularly limited, and alkyl anthraquinone: alkyl tetrahydroanthraquinone is preferably 0.05:1~100:1, preferably 0.1:1~75: 1 is better, and 0.2:1~50:1 is even better. A particularly desirable combination of alkyl anthraquinone and alkyl tetrahydroanthraquinone is the combination of ethyl anthraquinone and ethyl tetrahydroanthraquinone.

The hydrogen peroxide production step can be performed according to a known production method of hydrogen peroxide by an anthraquinone method. The hydrogen peroxide production step generally includes the following steps: hydrogenating the working solution, oxidizing the hydrogenated working solution, and extracting the 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. The oxidation of the working solution after hydrogenation can be carried out, 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 carried out, for example, by mixing the oxidized working solution with water and separating the aqueous phase. The extracted hydrogen peroxide can also be subjected to treatment such as purification and concentration.

In the working solution regeneration step, the removal of inert substances from the working solution is carried out by a distillation step comprising the following steps: i) The first distillation step (hereinafter sometimes referred to as the preceding distillation step) is performed at atmospheric pressure or lower pressure Distillation is performed to recover aromatic hydrocarbons; ii) a second distillation step (hereinafter sometimes referred to as a rear-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 lower than atmospheric pressure, and the aromatic hydrocarbons contained in the working solution are recovered as a distillate. The distillation pressure is not particularly limited as long as it is a pressure capable of recovering aromatic hydrocarbons. Preferably, the distillation pressure at which aromatic hydrocarbons will be distilled but trioctyl phosphate and anthraquinones will not be distilled. The distillation temperature is not particularly limited as long as it can recover 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, and 150°C. ~185℃, etc. Preferably, the distillation temperature at which aromatic hydrocarbons are distilled but trioctyl phosphate and anthraquinones are not distilled is preferred. The distillation in the first distillation step is preferably continued until there is no more distillation in consideration of the recovery rate of aromatic hydrocarbons. The aromatic hydrocarbons distilled in the first distillation step are reused as components of the regeneration working solution.

The working solution used in the first distillation step is generally the working solution circulated in the hydrogen peroxide production step, and contains inert substances by-produced along with the generation of hydrogen peroxide. The working solution can be taken from any stage of the hydrogen peroxide production step but does not contain hydrogen peroxide, or the working solution after the extraction step even if it contains but a very small content (for example, the content is less than 0.35g/L), considering safety view is ideal. Inert substances such as by-products (oxides, decomposition products, etc.) from anthraquinones, solvents (aromatic hydrocarbons and trioctyl phosphate). By-products from anthraquinones, such as: tetrahydroanthraquinone epoxide, tetraoxonone, oxyallone, allonone and other anthraquinone monomer by-products, anthraquinone solvent adducts, anthraquinones Quinone polymers, 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 distilled at 160°C or higher at a lower pressure than that in the first distillation step, and anthraquinones and trioctyl phosphate are recovered as a distillate. As a result, by-products (high-boiling components) having a higher boiling point than anthraquinones and trioctyl phosphate can be removed. The distillation pressure is not particularly limited as long as the anthraquinones and trioctyl phosphate can be recovered, 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 at which the anthraquinones and trioctyl phosphate are distilled but the by-products are small is preferred. The distillation temperature is not particularly limited as long as the anthraquinones and trioctyl phosphate can be recovered. 260℃, etc. In some aspects, the upper limit of the distillation temperature in the second distillation step may be less than 200°C. Therefore, in this aspect, the distillation temperature range of the second distillation step can be, for example: 160°C-199°C, 160°C-198°C, 160°C-197°C, 160°C-196°C, 160°C-195°C, 160°C ℃~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℃, etc. The distillation temperature is preferably such that the anthraquinones and trioctyl phosphate are distilled off but the by-products are less distilled.

The distillation in the second distillation step is preferably continued until the distillation stops, considering the point of view of the recovery rate of anthraquinones. In addition, the average residence time of the second distillation step is not particularly limited, but is, for example, 1 hour or more. "Retention time" refers to the time from the start of distillation or bottom production in a distillation step until it stops, and "average retention time" refers to the simple arithmetic mean of the retention times when the same distillation step is performed twice . The average residence time of the second distillation step can be, for example, a range of 1 hour to 10 hours, a range of 6 hours to 10 hours, and the like. When the average residence time is more than 1 hour, the recovery rate of anthraquinones will be improved, and by-products from anthraquinones will be converted into anthraquinones with hydrogen peroxide generating ability, and there will be hydrogen peroxide generating ability. The benefits of increased amounts of anthraquinones. For example, the by-product tetrahydroanthraquinone epoxide is converted into tetrahydroanthraquinone with hydrogen peroxide generating ability. Anthraquinones and trioctyl phosphate distilled from the second distillation step are reused as components of the regeneration working solution.

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

In one aspect, the method for producing hydrogen peroxide of the present invention further comprises the following steps: separating anthraquinones and trioctyl phosphate from the distillate of the second distillation step. The separation of anthraquinones and trioctyl phosphate can be carried out by recrystallizing the anthraquinones. The recrystallization of anthraquinones can be carried out by heating anthraquinones to dissolve in a recrystallization solvent and then cooling. After recrystallization, the recrystallized anthraquinones can be recovered and reused. The trioctyl phosphate separated from the anthraquinones can be separated from the recrystallization solvent by distillation or the like and reused. The solvent for recrystallization is preferably anthraquinone which has a larger difference between the solubility during 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, tert-butanol, 2-ethylhexanol, etc.), those used as working solutions. Non-polar solvents (aromatic hydrocarbons, etc.), polar solvents (TOP, diisobutylmethanol, tetrabutylurea, methylcyclohexyl acetate, etc.) used for the components, etc. The recrystallization solvent may be composed of a single solvent or a mixture of multiple solvents. The amount of the recrystallization solvent relative to the working solution is preferably one that can well perform recrystallization of anthraquinones. For example, it can be the volume of the solvent per unit weight of the working solution (eg g/mL), 1~20 times, 2~15 times, 3~10 times, 4~8 times, etc. By including the step of separating the anthraquinones and trioctyl phosphate, the anthraquinones can be recovered in a purer form. Therefore, the concentration of by-products contained in the regeneration working solution can be further reduced.

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

If the composition ratio of the solvent in the working solution changes, the density, viscosity and partition coefficient of the working solution also change. If these parameters are changed, the operation 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 regeneration working solution should be adjusted to be close to the value of the working solution in the circulating treatment. For example: the solvent composition ratio (%) of the regenerated working solution should be adjusted to be within ±20% of the working solution of the circulating treatment, preferably within ±10%, and more preferably within ±5% (but adjusted The total solvent composition ratio after that does not exceed 100%). That is, when the solvent of the working solution is composed of aromatic hydrocarbons and trioctyl phosphate, and the solvent composition ratio (volume ratio) in the circulating treatment is aromatic hydrocarbons: trioctyl phosphate = 70%: 30%, it should be adjusted to The solvent composition ratio of the regeneration working solution is 90%: 10%-50%: 50%, preferably 80%: 20%-60%: 40%, more preferably 75%: 25%-65%: 35%.

In an actual factory, the concentration of anthraquinones in the working solution in the circulating treatment gradually decreases over time, so it is appropriate to replenish new anthraquinones while operating. In order not to decrease the concentration of anthraquinones in the circulating treatment, the concentration of anthraquinones in the regeneration working solution should be adjusted to be the same as that in the circulating treatment, or above the concentration of anthraquinones in the circulating treatment and below the saturation concentration of anthraquinones . For example: in the working solution containing aromatic hydrocarbons, trioctyl phosphate, ethylanthraquinone and ethyltetrahydroanthraquinone, the total concentration of ethylanthraquinone and ethyltetrahydroanthraquinone in the regeneration working solution should be adjusted It is 0.1~1.4mol/L, preferably 0.3~1.2mol/L, more preferably 0.5~1.0mol/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 also be mixed. In certain aspects, aromatic hydrocarbons, trioctyl phosphate and/or anthraquinones from other supply sources, including commercial products, or new synthetic products.

In the step of preparing the regeneration working solution for circulation, the crude regeneration working solution obtained in the regeneration step of the working solution is washed with alkali to prepare the regeneration working solution for circulation. The regeneration working solution for recycling refers to the regeneration working solution which is especially suitable for the recycling treatment after alkali cleaning. The alkaline cleaning can be carried out by cleaning 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 cleaning may be any alkali metal in Group Ia of the periodic table, and lithium, sodium or potassium are preferred. The reagents containing them are not particularly limited, and examples thereof include lithium hydroxide, sodium hydroxide, sodium carbonate, sodium hydrogencarbonate, sodium borate, sodium diphosphate, sodium boron dioxide, sodium nitrite, sodium borate trioxide, and sodium hydrogenphosphate. , 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, potassium hydroxide, more preferably sodium hydroxide, sodium carbonate, sodium bicarbonate, potassium hydroxide, especially hydrogen Sodium oxide, sodium carbonate, sodium bicarbonate. The pH of the alkali aqueous solution containing an alkali metal is preferably 8 or more, more preferably 10 or more, particularly 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 having a volume of 0.2 times 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 the volume or more. For the contacting method, generally known mixing means can be used. For example: stirring, shaking and bubbling with inert gas, co-current and alternating contact methods, etc., but not limited to these, as long as it is a method that can efficiently contact the crude regeneration working solution with the alkaline aqueous solution. In addition, there is no important upper limit for the capacity of the alkaline aqueous solution to be contacted, and it can be appropriately selected according to the convenience of the contacting device and operation.

The contact time between the crude regeneration working solution and the alkaline aqueous solution is, for example, 1 minute or more, more preferably 3 minutes or more, especially 5 minutes or more, and can be appropriately selected according to the contact device and the convenience of operation. The contact temperature between 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 and discharged from the crude regeneration working solution. The alkaline cleaning can be performed more than once, for example, once, twice or three times or more. By subjecting the regeneration working solution to alkaline washing, the hydrogenation activity of the regeneration working solution can be improved compared to the case of washing only with water. In addition, when the crude regeneration working solution contains acidic impurities, there is an advantage that the acidic impurities can be removed by alkaline cleaning.

In one aspect, in the step of preparing the recycled regeneration working solution, the moisture content of the crude regeneration working solution is adjusted to be 20%-160% of the saturated moisture 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 saturated 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 water content of the regenerated working solution returned to the recycling treatment should be higher than that of the crude regeneration working solution. By washing the crude regeneration working solution with an alkaline aqueous solution, the water content of the regeneration working solution can be increased to the vicinity of the saturated moisture content. When the alkali cleaning is not within the desired water content range, the water content can be adjusted by dehydration treatment, adding water, washing with water, and the like.

In the step of preparing the regeneration working solution for circulation, in addition to alkali cleaning, cleaning with water may be performed. The water used for washing is preferably distilled water, ion-exchanged water, or water purified by reverse osmosis or the like, but water purified by methods other than the above can also be preferably used. In particular, the water used for washing is preferably pure water. The washing with water can be performed in the same manner as the alkaline washing, except that water is used as the washing medium. Therefore, the capacity of water to the crude regeneration working solution, the contact method with the crude regeneration working solution, the contact time, the contact temperature, the contact pressure, etc., are the same as those described above for the alkaline cleaning. The washing with water may be carried out before or after the alkali washing, and may be carried out both before and after. The washing with water can be performed more than once, for example: 1 time, 2 times or 3 times or more.

In the preparation step of the regeneration working solution for circulation, in addition to alkali cleaning, a treatment of regenerating anthraquinones from by-products derived from anthraquinones by using a regeneration catalyst can also be performed. The treatment with the regeneration catalyst can be carried out by passing the regeneration working solution before or after the alkaline cleaning through a fixed bed or a fluidized bed equipped with the regeneration catalyst. Sometimes one pass of liquid is not enough, so it is better to circulate the liquid. The regeneration catalyst is preferably activated alumina or silica alumina, more preferably activated alumina. The surface area and particle size of the regeneration catalyst can 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, more preferably 50°C to 150°C. In addition, as the reaction progresses, hydroquinones are accumulated and the progress of a part of the regeneration reaction is slowed down. Therefore, it is preferable to oxidize the hydroquinones by contacting with oxygen or air in the middle of the circulating liquid. In addition, it may be performed while removing the hydrogen peroxide produced at this time.

In one aspect, the hydrogen peroxide production method of the present invention includes the step of returning the aforementioned regeneration working solution for recycling to the hydrogen peroxide production step. The recycled regeneration working solution 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 certain step" refers to returning to an arbitrary stage from the stage before the end of the step to the stage before the end of the step. For example, returning the regenerated working solution for recycling to the hydrogenation step 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 certain aspects, the recycled regenerated working solution is returned to the hydrogenation step. In this aspect, the high hydrogenation activity of the regenerated working solution for recycling can be utilized, which is advantageous. A specific example of this aspect includes mixing the regeneration working solution for circulation with the circulating working solution before the hydrogenation device (hydrogenation tower), and introducing the obtained mixed solution into the hydrogenation device. In another specific aspect, the recycled regenerated working solution is returned to the oxidation step and/or the extraction step. This aspect is advantageous when the water content of the regeneration working solution for recycling is low.

Another aspect of the present invention relates to a method for producing a regenerated working solution for circulation (hereinafter sometimes referred to as "the method for producing a regenerated working solution for recycling of the present invention"), which has the following steps: a step of regenerating the working solution, which comprises the following steps: A working solution for the production of hydrogen peroxide from a family of hydrocarbons, trioctyl phosphate, anthraquinones, and inert substances by-produced with the generation of hydrogen peroxide, remove the inert substances, and prepare a crude product from which the inert substances have been removed a regeneration working solution; and a step of preparing a regenerating working solution for circulation, wherein the crude regeneration working solution is subjected to alkali washing to prepare a regeneration working solution for recycling; the regeneration step of the working solution has: i) a first distillation step, at atmospheric pressure or lower Distillation under pressure to recover aromatic hydrocarbons; ii) 2nd distillation step, and then distillation at lower pressure above 160°C to recover anthraquinones and trioctyl phosphate. The features of each step of the method for producing a regenerated working solution for recycling of the present invention are the same as those of the corresponding steps in the method for producing hydrogen peroxide of the present invention.

Another aspect of the present invention relates to a method for producing hydrogen peroxide (hereinafter sometimes referred to as "the method A for producing hydrogen peroxide of the present invention"), which has the following steps: The working solution of family hydrocarbons, trioctyl phosphate, and anthraquinone 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 make it circulated; a working solution regeneration step, which removes the by-produced inert substances from the aforementioned working solution from the aforementioned working solution and prepares a regeneration working solution; and a regeneration working solution preparation step for recycling, wherein the aforementioned crude regeneration working solution is converted into Washing with water or alkali, and preparing a regenerated working solution for circulation; The aforementioned working solution regeneration step includes: i) a first distillation step, which is distilled at atmospheric pressure or lower to recover aromatic hydrocarbons; ii) a second distillation step, Then, distillation above 160°C is carried out under lower pressure to recover anthraquinones and trioctyl phosphate. This aspect is the same as the hydrogen peroxide production method of the present invention, except that the alkali washing of the crude regeneration working solution is not necessary and can be replaced by washing with water. As shown in Example 4, even if the crude regeneration working solution was washed with water only, the hydrogenation activity of the regeneration working solution containing trioctyl phosphate was better than that of the working solution in circulation. 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 the condition that alkali cleaning is not required.

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

Another aspect of the present invention relates to a method for producing hydrogen peroxide (hereinafter sometimes referred to as "the method B for producing hydrogen peroxide of the present invention"), comprising the following steps: a step for producing hydrogen peroxide, which contains aromatic hydrocarbons , polar solvent, and the working solution of anthraquinone are hydrogenated and then oxidized to generate hydrogen peroxide, extract the hydrogen peroxide from the working solution, and return the working solution after the hydrogen peroxide is extracted to the hydrogenation step to make it circulate; The working solution regeneration step is to remove the by-produced inert substances from the aforementioned working solution along with the generation of the aforementioned hydrogen peroxide to prepare a regeneration working solution; and the regeneration working solution for recycling step is to perform alkaline cleaning on the aforementioned crude regeneration working solution, and prepare a regenerated working solution for recycling; the aforementioned working solution regeneration step has: i) a 1st distillation step, which is distilled at atmospheric pressure or lower to recover aromatic hydrocarbons; and ii) a 2nd distillation step, followed by a lower pressure The anthraquinones are recovered by distillation at lower temperature and above 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 in Example 4, by subjecting the crude regeneration working solution to alkali washing, the hydrogenation activity of the obtained regeneration working solution can be improved compared with the case of washing with water, but it is considered that it contains polar solvents other than trioctyl phosphate. The same goes for the working solution. In the above description of the hydrogen peroxide production method of the present invention, the polar solvent is not specified as trioctyl phosphate, and the polar solvent is recovered in either the first distillation step or the second distillation step. The conditions 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, including, for example: alcohols (for example: diisobutylmethanol (DIBC), 2-octanol), tetra-substituted urea (for example: tetrabutylurea (TBU)), phosphoric acid ester (for example: trioctyl phosphate), 2-pyrrolidone or alkyl cyclohexyl 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 producing a regenerated working solution for circulation (hereinafter sometimes referred to as "the method B for producing a regenerated working solution for recycling of the present invention"), which has the following steps: a step of regenerating the working solution, from which the Hydrogen peroxide production working solution for family hydrocarbons, polar solvents, anthraquinones, and inert substances by-produced with the generation of hydrogen peroxide to remove the aforementioned inert substances, and prepare a crude regeneration working solution from which the inert substances have been removed; and the preparation step of the regenerated working solution for circulation, the above-mentioned crude regeneration working solution is alkali-washed, and prepared into a regenerated working solution for circulation; the regeneration step of the above-mentioned working solution has: i) the first distillation step, at atmospheric pressure or lower pressure Distillation is performed to recover aromatic hydrocarbons; and ii) a second distillation step, followed by recovery of anthraquinones by distillation at lower pressure and above 160°C, and the polar solvent is either the first distillation step or the second distillation step Recycle. The features of each step of the method B for producing a regenerated working solution for recycling of the present invention are the same as those of the corresponding steps in the method B for producing hydrogen peroxide of 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 washing 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 first-stage distillation distillate tank and/or a second-stage distillation distillate tank. One aspect of the hydrogen peroxide production system of the present invention is described below with reference to the drawings.

1 depicts the peroxidation of the present invention comprising 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 first-stage distillation distillate tank 9, and a second-stage distillation distillate tank 10 Hydrogen production system A. The distillation column 1 is provided with an unidentified component discharge line 8 and a distillate conveying line 7. The distillate conveying line 7 and the first-stage distillation distillate tank 9 are communicated with the first-stage distillation distillate conveying line 7a, and the distillate conveying line 7 It is communicated with the back-stage distillation distillate tank 10 by the back-stage distillation distillate conveying line 7b; It communicates with the preparation tank 2 by the post-distillate supply line 12, the preparation tank 2 and the washing tank 3 are communicated with the crude regeneration working solution supply line 13, and the washing tank 3 is connected with the alkaline solution supply line 14 and the water supply line 15. The cleaning tank 3 is provided with a waste liquid line 17, and the cleaning tank 3 and the hydrogenation tower 4 are communicated with 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 communicated with the hydrogenation 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 communicated with the oxidation working solution supply line 23, and the extraction tower 6 has The water supply line 24 and the hydrogen peroxide delivery line 25, the distillation column 1 and the extraction column 6 are communicated with the supply line 26 of the working solution after the hydrogen peroxide is extracted, and the regenerated working solution supply line 16 and the hydrogen peroxide are extracted for circulation. After that, the supply line 26 of the working solution is communicated with the working solution circulation line 27 after the hydrogen peroxide has been extracted. In addition, the first-stage distillation distillate conveying line 7a, the second-stage distillation distillate conveying line 7b, the unidentified component discharge line 8, the first-stage distillation distillate supply line 11, the second-stage distillation distillate supply line 12, and the crude regeneration working solution supply line 13. The alkali solution supply line 14 , the water supply line 15 , the regeneration working solution supply line 16 for circulation, 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 is reacted in the hydrogenation tower 4 with a hydrogen-containing hydrogenating agent 32 from the hydrogenating agent supply line 19 (eg, hydrogen, a mixture of an inert gas (nitrogen, etc.) and hydrogen, etc.) to generate anthraquinones from anthraquinones. The unreacted hydrogenation agent is repeatedly supplied to the hydrogenation column 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 (such as air, oxygen, etc.) sent to the oxidant supply line 21, and anthraquinones are generated. class with hydrogen peroxide. Unreacted oxidant 34 is exhausted from exhaust line 22 . The oxidized working solution containing hydrogen peroxide enters the extraction tower 6 through the oxidation working solution supply line 23, and the generated hydrogen peroxide is in the form of hydrogen peroxide water 36 by the water 35 supplied from the water supply line 24 Recovered from hydrogen peroxide feed line 25 . After the hydrogen peroxide is extracted, a part of the working solution enters the distillation column 1 through the supply line 26 of the working solution after the hydrogen peroxide is extracted, and the rest passes through the working solution circulation line 27 after the hydrogen peroxide is extracted, and merges into the regeneration for recycling. The working solution is supplied to line 16 and returned to hydrogenation column 4 .

The hydrogen peroxide that has entered the distillation column 1 is extracted and the working solution is supplied to the previous stage distillation at atmospheric pressure or lower. The pre-distillate distillate containing aromatic hydrocarbons distilled from the pre-distillation is stored in the pre-distillate tank 9 through the distillate transfer line 7 and the pre-distillate distillate transfer line 7a. The residue remaining in the distillation column 1 is supplied to the subsequent distillation at a pressure lower than that of the first distillation and at 160° C. or higher. The second-stage distillation distillate containing anthraquinones and trioctyl phosphate distilled from the second-stage distillation passes through the distillate transfer line 7 and the second-stage distillation distillate transfer line 7b and is stored in the second-stage distillation distillate tank 10 . The unidentified component 28 which is the residue after distillation in the second stage is discharged from the unidentified component discharge line 8 . The first-stage distillation distillate stored in the first-stage distillation distillate tank 9 and the second-stage distillation distillate stored in the second-stage distillation distillate tank 10 pass through the first-stage distillation distillate supply line 11 and the second-stage distillation distillate supply line, respectively. 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 alkaline solution 29 supplied from the alkaline solution supply line 14, and further washed with the water 30 supplied from the water supply line 15 as necessary to become the regeneration working solution for circulation. The alkaline solution or water used for washing is discharged from the waste liquid line 17 as the waste liquid 31 . The regenerated working solution for recycle passes through the regenerated working solution supply line 16 for recycle, joins the working solution from the recycle line 27 of the working solution after the hydrogen peroxide is extracted, and enters the hydrogenation tower 4 on the way.

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 provided with a recrystallization tank will be described with reference to FIG. 2 . In addition, 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 the description thereof will be omitted.

In this aspect, the rear-stage distillate supply line 12 connected to the rear-stage distillate tank 10 is connected to the recrystallization tank 37 , and the anthraquinones supply line 40 connected to the recrystallization tank 37 is connected to the preparation tank 2 . The recrystallization tank 37 is further connected with the recrystallization solvent supply line 39, the waste liquid line 41 and the filtrate conveying line 42. The recrystallization solvent supply line 39 communicates the recrystallization solvent tank 38 with the recrystallization tank 37, and the filtrate conveying line 42 will recrystallize. The tank 37 communicates with the distillation column 1 . The recrystallization solvent tank 38 is communicated with the distillate transportation line 7 through the distillation recrystallization solvent transportation line 7d, and the preparation tank 2 is communicated with the distillate transportation line 7 through the distillation TOP transportation line 7c. The recrystallization tank 37 is equipped with a temperature control device, and can recrystallize the anthraquinones by heating and dissolving the anthraquinones in the recrystallization solvent and by cooling after that. The recrystallization tank 37 is further provided with a filter, which can separate and filter the recrystallized anthraquinones.

In this aspect, the rear-stage distillate contained in the rear-stage distillate tank 10 enters the recrystallization tank 37 through the rear-stage distillate supply line 12 . In the recrystallization tank 37, the recrystallization solvent is supplied from the recrystallization solvent supply line 39, and 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 production 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 off from the filtrate sent to the distillation column 1, respectively, and the distilled recrystallization solvent passes through the distillate conveying line 7 and the distilling recrystallization solvent conveying line 7d and is contained in the recrystallization In the solvent tank 38, the distilled trioctyl phosphate is sent to the preparation tank 2 through the distillate transfer line 7 and the distillate TOP transfer line 7c.

The hydrogen peroxide production system of the present invention is not limited to the aspect described above, and various modifications can be made within the scope of the gist of the present invention. For example: in the hydrogen peroxide production system A shown in FIG. 1, (A1) does not set the first-stage distillation distillate tank 9 and the first-stage distillation distillate conveying line 7a connected to it, and the distillate conveying line 7 and the preparation The tank 2 is communicated with the first-stage distillation distillate supply line 11, (A2) The second-stage distillation distillate tank 10 and the second-stage distillation distillate transfer line 7b connected to it are not provided, but the distillate transfer line 7 and the preparation tank are connected. 2 Use the back-stage distillation distillate supply line 12 to communicate, (A3) do not set the front-stage distillate distillate tank 9 and the front-stage distillation distillate conveying line 7a connected to it, the back-stage distillation distillate tank 10 and the back stage connected to it Distillate transfer line 7b, and distillate transfer line 7 and preparation tank 2 are connected by front-stage distillate supply line 11 and rear-stage distillate supply line 12, (A4) No distillate transfer is provided Line 7, the first-stage distillation distillate tank 9 and the first-stage distillation distillate conveying line 7a connected to it, the second-stage distillation distillate tank 10 and the second-stage distillation distillate conveying line 7b connected to it, but the distillation column 1 is connected to the same. The preparation tank 2 communicates with the first-stage distillate supply line 11 and the second-stage distillation distillate supply line 12, and the like.

In addition, in the hydrogen peroxide production system B shown in FIG. 2 , in addition to the above-mentioned changes (A1) to (A4) of the hydrogen peroxide production system A, for example, (B1) the filtrate transfer line 42 and the distillation 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 with the distillate TOP conveying line 7c, and the distillate TOP tank and the preparation tank 2 are connected with The distillate TOP supply line is communicated, and (B3) is not provided with a filter in the recrystallization tank 37, but is provided in the middle of the anthraquinones supply line 40, or 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 can be removed from the line provided with the valve, as necessary, in at least one of the lines.

Hereinafter, the present invention will be described in more detail with examples, but the present invention is not limited thereto. [Example]

<Analysis method> Aromatic hydrocarbons, trioctyl phosphate, 2-ethylanthraquinone, and 2-ethyltetrahydroanthraquinone in the working solution and the sample obtained by each operation were quantified using a gas chromatography analyzer. As the gas chromatography analyzer, 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". Most of the "unknown ingredients" are presumed to be inert substances.

The density of the initial working solution and the regeneration working solution for circulation was measured using a Densitometer DA-640 manufactured by Kyoto Electronics Co., Ltd., and the viscosity was measured using a B-type viscometer manufactured by Tokyo Keiki Co., Ltd. The hydrogenation activity of the initial working solution and the regenerated working solution for recycle was evaluated according to the following method. A hydrogenation catalyst and a working solution were placed in a 100 mL 2-neck flask. A stirrer was connected to one port of the flask, and a hydrogen supply unit was connected to the other port. Also, the flask was sealed. The hydrogen supply part is composed of a hydrogen metering tube, a U-shaped tube pressure gauge and a water storage part. The height of the water storage part is adjusted according to the change of the liquid level of the U-shaped tube pressure gauge during the hydrogenation reaction, and the internal pressure of the flask is maintained. equal to atmospheric pressure. The hydrogen absorption amount was measured as the difference in the liquid level in the hydrogen metering tube. The flask was immersed in a 30°C water bath and left to stand for 10 minutes. After repeating the evacuation of the flask and the introduction of hydrogen three times, the stirrer was actuated. The amount of hydrogen absorption from the start of hydrogen absorption to 30 minutes later was measured. The amount of hydrogen absorbed is converted to a value of 1 atm at 0°C. The activity value of the hydrogenation catalyst is expressed in the standard state hydrogen absorption rate [NmL/(min×g)] per unit weight of the hydrogenation catalyst. As the hydrogenation catalyst, 0.05 g of 2 wt % Pd/silica dried at 120° C. or 0.1 g of 1 wt % Pd/silica alumina dried at 120° C. was used.

Example 1 The first distillation step and the second distillation step of the present invention were carried out on a small scale, and the initial working solution was compared with the regenerated working solution for recycle. <1st distillation step> The working solution 400g was put into the 500 mL flask with which the distillation apparatus was equipped. Distilled under reduced pressure, the vacuum degree was always controlled at 1.3kPa. The temperature in the flask was raised from room temperature to 182°C. Distillation was continued until finally no more distillation was obtained 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 pressure lower than that in the first distillation step. The degree of vacuum temporarily fluctuated between 0.03kPa and 0.15kPa from the beginning of distillation, but finally stabilized at 0.08kPa. The temperature in the flask was raised from room temperature to 202°C. Distillation was continued until finally no more distillation under the conditions of 0.08kPa and 202°C. <Distillation result> Table 1 shows the composition of the initial working solution, the distillate recovered by each distillation step, and the residue. As the aromatic hydrocarbon, a high-boiling aromatic naphtha (SWASOL1500, manufactured by Maruzen Petrochemical Co., Ltd., CAS No. 64742-94-5) was used (the same applies to Examples 2 to 4). In addition, since various reactions such as tetrahydroanthraquinone conversion into anthraquinone mainly occur during distillation, the weight may increase more than the initial working solution depending on the components. In addition, the "loss component" represents the amount lost in the experiment (the reason is considered to be the loss to the cold trap, the pump, etc.).

[Table 1] Composition of initial working solution, distillate and residue (material budget)

<Evaluation of Regeneration Working Solution for Circulation> A regeneration 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 be close to the solvent composition ratio of the initial working solution to obtain a crude regeneration working solution. The compositions of the initial working solution and the crude regeneration working solution are disclosed below. [Table 2] Composition of initial working solution and crude regeneration working solution

The crude regeneration working solution was washed with 2 times the volume of 30wt% sodium hydroxide aqueous solution and 2 times the volume of pure water in sequence, and used as the regeneration working solution for recycling. 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. In addition, when evaluating the hydrogenation activity, 0.05 g of 2 wt % Pd/silicon dioxide dried at 120° C. was used as a hydrogenation catalyst. 【Table 3】 Comparison of initial working solution and recycled working solution

<Isolation of Anthraquinones> About 200 mL of ethanol was added to 32 g of the distillate from the second distillation step, and the mixture was heated and dissolved, and then cooled to room temperature (recrystallization). The crystals were filtered and dried. The composition of the distillate from the second distillation step and the crystals recovered in the recrystallization is disclosed 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 components of the working solution. [Table 4] Composition of the distillate from the second distillation step and the crystals recovered by recrystallization

Example 2 In the present invention, the first distillation step and the second distillation step were carried out under conditions different from those in Example 1, and the initial working solution and the regenerated working solution for circulation were compared. <1st distillation step> The working solution 351g was put into the 500 mL flask with which the distillation apparatus was equipped. Distilled under reduced pressure, the vacuum degree was always controlled at 1.3kPa. The temperature in the flask was raised from room temperature to 157°C. Distillation was continued until finally no more distillation was obtained under the conditions of 1.3 kPa and 157°C. <Second distillation step> The residue obtained in the first distillation step is distilled at a pressure lower than that in the first distillation step. The degree of vacuum temporarily fluctuated between 10Pa and 150Pa at the beginning of distillation, but finally stabilized at 0.01kPa to 0.04kPa. The temperature in the flask was raised from room temperature to 181°C. Distillation was continued until finally no more distillation was obtained under the conditions of 0.01 kPa and 181°C. <Distillation result> Table 5 shows the composition of the initial working solution, the distillate recovered by each distillation step, and the residue.

[Table 5] Composition of initial working solution, distillate and residue (material budget)

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

Following the same cleaning procedure as in Example 1, a regeneration working solution for recycling was prepared. Table 7 discloses a comparison of the density, viscosity and hydrogenation activity of the initial working solution and the recycled regeneration working solution. In addition, when evaluating the hydrogenation activity, 0.1 g of 1 wt % Pd/silica alumina dried at 120° C. was used as a hydrogenation catalyst. 【Table 7】Comparison of initial working solution and recycled regeneration working solution

Example 3 The first distillation step and the second distillation step in the present invention were carried out under conditions different from those of Examples 1 and 2, and the initial working solution and the regenerated working solution for circulation were compared. <1st distillation step> In the same manner as in Example 2, 351 g of the working solution was charged into a 500 mL flask equipped with a distillation apparatus. Distilled under reduced pressure, the vacuum degree was always controlled at 1.3kPa. The temperature in the flask was raised from room temperature to 180°C. Distillation was continued until finally no more distillation was obtained under the conditions of 1.3 kPa and 180°C. <Second distillation step> The residue obtained in the first distillation step is distilled at a pressure lower 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. Distillation was continued until finally no more distillation was obtained under the conditions of 0.13 kPa and 250°C. <Distillation result> Table 8 shows the composition of the initial working solution, the distillate recovered by each distillation step, and the residue.

[Table 8] Composition of initial working solution, distillate and residue (material budget)

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

Following the same cleaning procedure as in Example 1, a regeneration working solution for recycling was prepared. Table 10 discloses a comparison of density, viscosity, hydrogenation activity. In addition, when evaluating the hydrogenation activity, 0.1 g of 1 wt % Pd/silica alumina dried at 120° C. was used as a hydrogenation catalyst. [Table 10] Evaluation of initial working solution and recycled regeneration working solution

Example 4 The crude regeneration working solution prepared in Example 2 was washed twice with 2 times the volume of pure water as the regeneration working solution for recycling (pure water washing). In the same manner as in Example 2, the hydrogenation activity test was carried out. As the hydrogenation catalyst, 0.1 g of 1 wt% Pd/silica alumina dried at 120°C was used. Table 11 discloses the results of the hydrogenation activity test. The hydrogenation activity of the regenerated working solution for recycle that was only washed with pure water was higher than that of the initial working solution, but the hydrogenation activity of the regenerated working solution for recycle (Example 2) that had been washed with alkali was higher. [Table 11] Hydrogenation activity

1‧‧‧Distillation column 2‧‧‧Preparation tank 3‧‧‧Washing tank 4‧‧‧Hydrogenation column 5‧‧‧Oxidation column 6‧‧‧Extraction column 7‧‧‧Distillate conveying line 7a‧‧‧ Front-stage distillation distillate conveying line 7b‧‧‧second-stage distillation distillate conveying line 7c‧‧‧distillation TOP conveying line 7d‧‧‧distillation recrystallization solvent conveying line 8‧‧‧unknown component discharge line9‧‧‧ Front-stage distillation distillate tank 10‧‧‧Second-stage distillation distillate tank 11‧‧‧Front-stage distillation distillate supply line 12‧‧‧Second-stage distillation distillate supply line 13‧‧‧Rough regeneration working solution supply line 14‧ ‧‧Alkaline solution supply line 15‧‧‧Water supply line 16‧‧‧Regeneration working solution supply line for circulation 17‧‧‧Waste liquid line 18‧‧‧Hydrogenating agent circulation line 19‧‧‧Hydrogenating agent supply line 20‧‧ ‧Hydrogenation working solution supply line 21‧‧‧oxidant supply line 22‧‧‧exhaust line 23‧‧‧oxidation working solution supply line 24‧‧‧water supply line 25‧‧‧hydrogen peroxide delivery line 26‧‧‧pass Supply line for working solution after hydrogen oxide is extracted 27‧‧‧Circulation line for working solution after hydrogen peroxide is extracted 28‧‧‧Unknown components 29‧‧‧Alkaline solution 30‧‧‧Water 31‧‧‧Waste liquid 32‧ ‧‧Hydrogenating agent 33‧‧‧Oxidizing agent 34‧‧‧Unreacted oxidizing agent 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 Delivery Line V‧‧‧Valve

FIG. 1 is a schematic diagram of one aspect of the hydrogen peroxide production system of the present invention. FIG. 2 is a schematic diagram of one aspect of the hydrogen peroxide production system of the present invention including a recrystallization tank.

Claims (16)

A method for producing hydrogen peroxide, comprising the following steps: a step of producing hydrogen peroxide, wherein a working solution containing aromatic hydrocarbons, trioctyl phosphate and anthraquinone is hydrogenated and then oxidized to generate hydrogen peroxide , extract 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 circulate it; the working solution regeneration step, from the working solution will be accompanied by the generation of the hydrogen peroxide. The raw inert substances are removed, and a crude regeneration working solution from which the inert substances have been removed is prepared; and the regeneration working solution preparation step for recycling, the crude regeneration working solution is subjected to alkali washing, and a regeneration working solution for recycling is prepared; the working solution The regeneration step has the following steps: i) a first distillation step to recover aromatic hydrocarbons by distillation at atmospheric pressure or lower; and ii) a second distillation step, followed by lower pressure and above 160°C Distillation to recover anthraquinones and trioctyl phosphate. According to the method for producing hydrogen peroxide of claim 1, wherein the pressure in the first distillation step is in the range of 1 kPa to 100 kPa. According to the method for producing hydrogen peroxide of claim 1, wherein the pressure in the second distillation step is 1 kPa or less. According to the method for producing hydrogen peroxide according to the claim 1 of the claimed scope, the temperature in the second distillation step is in the range of 160°C to 300°C. The method for producing hydrogen peroxide of claim 1, wherein the anthraquinones contain alkyl anthraquinone and alkyl tetrahydroanthraquinone. The method for producing hydrogen peroxide according to any one of the claims 1 to 5 of the claimed scope includes the step of returning the regenerated working solution for recycling to the step of producing hydrogen peroxide. The method for producing hydrogen peroxide according to claim 6, wherein the solvent composition ratio of the crude regeneration working solution relative to the solvent composition ratio of the working solution circulated in the hydrogen peroxide production step is within the range of ±20% . The method for producing hydrogen peroxide according to claim 6, wherein the concentration of anthraquinones in the crude regeneration working solution is above the concentration of anthraquinones in the working solution circulated in the hydrogen peroxide production step and Within the range below the saturation concentration of anthraquinones. The method for producing hydrogen peroxide as claimed in item 6 of the scope of the patent application, wherein, in the step of preparing the regeneration working solution for circulation, the moisture content of the regeneration working solution is adjusted to be 20% to 160% of the saturated moisture content. According to the method for producing hydrogen peroxide as claimed in item 6 of the claimed scope, wherein the step of preparing the regenerated working solution for circulation further comprises the step of washing the regenerated working solution after alkali washing with water. The method for producing hydrogen peroxide according to any one of claims 1 to 5 of the claimed scope further includes a step of separating anthraquinones and trioctyl phosphate from the distillate of the second distillation step. The method for producing hydrogen peroxide according to claim 11, wherein the step of separating the anthraquinones and trioctyl phosphate is performed by recrystallization. A hydrogen peroxide production system, comprising a distillation column, a preparation tank, a washing tank, a hydrogenation column, an oxidation column and an extraction column, the distillation column is provided with an unidentified component discharge line, the distillation column and the preparation tank utilize a front-stage distillation distillate supply line, and The latter stage distillate supply line is connected, the preparation tank and the washing tank are connected by the crude regeneration working solution supply line, the washing tank is connected with the alkaline solution supply line and the water supply line, and the washing tank is provided with a waste liquid line. The tank and the hydrogenation tower are communicated with the supply line of the regenerating working solution for circulation, the hydrogenation tower is connected with the hydrogenation agent supply line, the hydrogenation tower and the oxidation tower are communicated with the supply line of the hydrogenation working solution, the oxidation tower is connected with the oxidant supply line, and the oxidation tower is connected with the extraction line. The tower is connected by the supply line of the oxidation working solution, the extraction tower is provided with a hydrogen peroxide conveying line, the distillation tower and the extraction tower are connected by the supply line of the working solution after the hydrogen peroxide is extracted, and the distillation tower is used to carry out front-stage distillation and rear-stage distillation. In the first stage distillation, the distillation carried out at atmospheric pressure or lower pressure is used to recover aromatic hydrocarbons, and the second stage distillation is followed by the first stage distillation, and the distillation carried out at a lower pressure and above 160°C is used to recover the aromatic hydrocarbons. Recovery of anthraquinones and trioctyl phosphate. For example, the hydrogen peroxide production system of item 13 of the scope of application, further includes a front-stage distillation distillate tank, the distillation column and the front-stage distillation distillate tank are connected by a front-stage distillation distillate conveying line, and the front-stage distillation distillate tank is connected with The preparation tank is communicated with the pre-stage distillation distillate supply line. For example, the hydrogen peroxide production system of item 13 of the scope of the application is further provided with a back-stage distillation distillate tank, the distillation column and the back-stage distillation distillate tank are connected by a back-stage distillation distillate conveying line, and the back-stage distillation distillate tank is connected with The preparation tank is communicated with the back-stage distillation distillate supply line. For example, the hydrogen peroxide production system of the 13th item of the patent application scope is further equipped with a recrystallization tank, the recrystallization tank is equipped with a filter and a waste liquid line, the recrystallization tank is connected with the recrystallization solvent supply line, and the recrystallization tank and the distillation tower utilize the back-stage distillation. The distillate supply line is connected, and the recrystallization tank and the preparation tank are connected by an anthraquinone supply line.

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