Hydrogen peroxide production process

Abstract

The present invention relates to a process for producing hydrogen peroxide by the AO process comprising the two alternating steps of: hydrogenation of a working solution in the presence of a catalyst, said working solution containing at least one quinone dissolved in at least one organic solvent, to obtain at least one corresponding hydroquinone; and oxidation of said at least one hydroquinone; characterized in that the organic solvent conforms to the formula (I): (I) R1-O-R2 in which R1 is an aryl group comprising from 6 to 18 carbon atoms and R2 is an alkyl group comprising from 1 to 8 carbon atoms. No figures

Description

Title of the invention: Process for the production of hydrogen peroxide. Technical field

[0001] The present invention relates to a process for the production of hydrogen peroxide and the use of a specific solvent for the production of hydrogen peroxide. Technical background

[0002] The most common process for the production of hydrogen peroxide is the anthraquinone process. In this process (also called the cyclic auto-oxidation (AO) process), a quinone is dissolved in a suitable mixture of organic solvents, a so-called working solution, and is hydrogenated to form the corresponding hydroquinone. The hydroquinone is then reoxidized to the quinone with oxygen (usually air) with the simultaneous formation of hydrogen peroxide, which can then be extracted with water while the quinone is returned with the working solution to the hydrogenation step.

[0003] The anthraquinone process is widely described in the literature, for example in Kirk-Othmer, "Encyclopedia of Chemical Technology", 49th Ed., 1993, Vol. 13, pp. 961-995.

[0004] For the process to function correctly, it is necessary to use a solvent mixture for the working solution in which both quinones and hydroquinones are soluble. Therefore, the solvent mixture in the working solution normally comprises one or more solvents for quinones and one or more solvents for hydroquinones. Quinones dissolve readily in nonpolar aromatic solvents, while hydroquinones dissolve well in polar solvents.

[0005] For quinones, various aromatic solvents are proposed in the literature such as benzene, xylene (US 2 158 525), trimethylbenzene (GB 747 190), tetramethylbenzene (WO 2001 / 098204) and mixtures of polyalkylated benzenes (US 3 328 128, EP 3 342 750, FR 1 406 409).

[0006] In addition, certain nitrogen compounds are also known as solvents for hydroquinones. The uses of carboxylic acid amides (US 4 046 868), substituted ureas (US 3 767 778), alkyl-substituted pyrrolidones (US 4 394 369) and alkyl-substituted caprolactams (EP 0 286 610) are described in the literature.

[0007] The aromatic solvents proposed in the literature are flammable and produce explosive vapors when mixed with oxygen or air. (involving serious risks of fire and explosion in a large-scale commercial factory).

[0008] There is still a need for a solvent used for the production of hydrogen peroxide which reduces the costs of the process and increases the safety and productivity of the process. Summary of the invention

[0009] The first object of the invention is to provide a process for the production of hydrogen peroxide by the AO process comprising the two alternating steps of: - hydrogenation of a working solution in the presence of a catalyst, said working solution containing at least one quinone dissolved in at least one organic solvent, to obtain at least one corresponding hydroquinone; and - oxidation of said at least one hydroquinone characterized in that the organic solvent corresponds to formula (I): (I) R'-O-R2 in which: - R1 is an aryl group comprising 6 to 18 carbon atoms; and - R2 is an alkyl group comprising 1 to 8 carbon atoms.

[0010] According to some embodiments, when R2 is a methyl group, R1 is different from a phenyl group.

[0011] According to some embodiments, the organic solvent has a specific density equal to or less than 0.95.

[0012] According to some embodiments, the organic solvent has a vapor pressure equal to or less than 450 Pa at 20 °C.

[0013] According to some embodiments, the organic solvent has a solubility in water equal to or less than 200 mg / kg.

[0014] According to some embodiments, the organic solvent of formula (I) has a flash point above 60 °C.

[0015] According to some embodiments, R'-O- is derived from a phenol selected from o-cresol, m-cresol, p-cresol, o-ethylphenol, m-ethylphenol, p-ethylphenol, o-propylphenol, m-propylphenol, p-propylphenol, 2,6-dimethylphenol, 2,4-dimethylphenol, 3,4-dimethylphenol, or from a naphthol selected from 1-naphthol and 2-naphthol, and / or wherein R2 is a group selected from a methyl, an ethyl, an n-propyl, an i-propyl, an n-butyl, an i-butyl, a t-butyl, an n-pentyl, a neopentyl and an n-hexyl.

[0016] According to some embodiments, the working solution consists of the organic solvent of formula (I) and the quinone.

[0017] According to some embodiments, the quinone is preferably an anthraquinone, more preferably an alkylanthraquinone and / or a tetrahydroalkylan-thraquinone, preferably selected from 2-ethylanthraquinone, 2-isopropylanthraquinone, 2-n-butylanthraquinone, 2-sec-butylanthraquinone, 2-tert-butylanthraquinone, 2-amylanthraquinone, 2-sec-amylanthraquinone, 2-tert-amylanthraquinone or mixtures thereof.

[0018] According to some embodiments, the working solution further comprises an additional solvent selected from alkyl phosphates, tetraalkylureas, alkylcyclohexanol esters, high boiling point alcohols and mixtures thereof.

[0019] The invention further relates to the use of an organic solvent to dissolve a quinone in a working solution for the production of hydrogen peroxide, the organic solvent having the formula (I): (I) R'-O-R2 in which: - R1 is an aryl group comprising 6 to 18 carbon atoms; and - R2 is an alkyl group comprising 1 to 8 carbon atoms.

[0020] According to some embodiments, when R2 is a methyl group, R1 is different from a phenyl group.

[0021] The present invention addresses the need mentioned above. In particular, the invention provides a solvent used for the production of hydrogen peroxide that reduces process costs and increases process safety and productivity.

[0022] This is achieved with the organic solvent of formula (I) according to the present invention. More specifically, quinones have increased solubility in this solvent, which allows the process to be carried out at a lower temperature, thereby reducing the costs associated with the production of hydrogen peroxide and the risks associated with the flammability of the solvent. Furthermore, with increased solubility, reaction rates can be increased, thereby increasing the productivity of the process.

[0023] Furthermore, the presence of a nitrogen atom in the organic solvent increases the solvent's polarity, which also significantly improves the solubility of hydroquinone. With increased hydroquinone solubility, reaction rates also increase, and plant productivity can thus be enhanced.

[0024] Furthermore, the fact that the organic solvent according to the invention preferably has a flash point above 60 °C helps to limit the risk of fire related to the flammability of the solvent.

[0025] Advantageously, the fact that the organic solvent according to the invention has a specific density equal to or less than 0.95 allows the separation of the solvent from the water. This is useful during the step of extracting hydrogen peroxide from the working solution.

[0026] Also advantageously, the organic solvent according to the present invention can have a vapor pressure equal to or less than 450 Pa at 20 °C, which makes it possible to keep the vapors in the reactors below explosive limits at all times even when the reaction is carried out at high temperatures.

[0027] Also advantageously, the organic solvent according to the present invention may have a water solubility equal to or less than 200 mg / kg. Such reduced water solubility for the organic solvent makes it possible to reduce solvent loss, particularly during the extraction step of the process (in which the oxidized working solution is treated with water to extract the hydrogen peroxide). Furthermore, such reduced water solubility for the organic solvent makes it possible to provide a crude hydrogen peroxide solution of higher purity. Detailed description

[0028] The invention will now be described in more detail without limitation in the following description.

[0029] Working solution

[0030] The working solution according to the invention comprises at least one quinone in at least one organic solvent. The organic solvent is used to solubilize the quinone.

[0031] At least one organic solvent corresponds to the following formula: (I) R'-O-R2 in which: - R1 is an aryl group comprising 6 to 18 carbon atoms; and - R2 is an alkyl group comprising 1 to 8 carbon atoms.

[0032] According to some embodiments, R1 can be a substituted or unsubstituted aryl group.

[0033] Preferably, R1 is an aryl group comprising 6 to 12 carbon atoms.

[0034] R1 may comprise one or more heteroatoms selected from oxygen, nitrogen and a halogen selected from -F, -Cl, -Br and -I. Preferably, R1 may comprise an oxygen atom.

[0035] In the case where R1 is an unsubstituted aryl group, it can be chosen from a phenyl group or a naphthyl group.

[0036] In the case where R1 is a substituted aryl group, it may comprise one or more substituents. Preferably, R1 comprises one or two substituents.

[0037] The different substituents can be present in ortho, meta or para positions relative to the position of the oxygen atom of the organic solvent of formula (I) bonded to the group R1.

[0038] Such substituents may be chosen from an alkyl group, linear or branched, comprising from 1 to 4 carbon atoms, a hydroxy group, an amine or a halogen chosen from -F, -Cl, -Br and -I.

[0039] The alkyl group can be chosen from a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group and a t-butyl group.

[0040] Preferably, such a substituent can be an alkyl group, more preferably chosen from a methyl group, an ethyl group or a propyl group.

[0041] According to some preferred embodiments, R1 comprises a single substituent which is preferably an alkyl group more preferably chosen from a methyl group, an ethyl group or a propyl group.

[0042] According to some preferred embodiments, R1 comprises two substituents: two alkyl groups preferably chosen from a methyl group, an ethyl group or a propyl group.

[0043] According to some embodiments, R'-O- can be derived from a phenol selected from o-cresol, m-cresol, p-cresol, o-ethylphenol, m-ethylphenol, p-ethylphenol, o-propylphenol, m-propylphenol, p-propylphenol, 2,6-dimethylphenol, 2,4-dimethylphenol, 3,4-dimethylphenol, or from a naphthol selected from 1-naphthol and 2-naphthol.

[0044] As mentioned above, R2 is an alkyl group comprising from 1 to 8 carbon atoms, preferably from 2 to 8 carbon atoms, and more preferably from 2 to 6 carbon atoms. R2 can be linear or branched.

[0045] According to preferred embodiments, R2 can be selected from a methyl, an ethyl, an n-propyl, an i-propyl, an n-butyl, an i-butyl, a t-butyl, an n-pentyl, a neopentyl, and an n-hexyl. Preferably, R2 can be selected from a methyl, an ethyl, and a propyl.

[0046] Preferably, when R2 is a methyl group, R1 is different from a phenyl group.

[0047] According to preferred embodiments, the organic solvent according to the present invention may have a flash point above 60 °C, preferably above 62.5 °C and more preferably above 65 °C. The flash point may be determined by a closed-cup apparatus according to ASTM D3278.

[0048] The organic solvent according to the present invention may have a specific gravity equal to or less than 0.95, and preferably equal to or less than 0.94. According to preferred embodiments, the organic solvent according to the present invention may have a specific gravity from 0.89 to 0.95, and preferably from 0.90 to 0.94. The specific gravity can be determined using a hydrometer according to ASTM D891.

[0049] Furthermore, the solvent of formula (I) may have a vapor pressure equal to or less than 450 Pa, preferably equal to or less than 400 Pa, and more preferably equal to or less than 350 Pa at 20 °C. For example, the solvent of formula (I) may have a vapor pressure equal to or less than 450 Pa, or equal to or less than 400 Pa, or equal to or less than 350 Pa, or equal to or less than 300 Pa, or equal to or less than 250 Pa, or equal to or less than 200 Pa, or equal to or less than 250 Pa, or equal to or less than 200 Pa, or equal to or less than 150 Pa, or equal to or less than 100 Pa, at 20 °C. The vapor pressure may be determined by ebulliometry according to ASTM E1719.

[0050] According to certain preferred embodiments, the organic solvent is insoluble (or essentially insoluble) in water, and preferably has a solubility in water equal to or less than 200 mg / kg, preferably equal to or less than 190 mg / kg, and more preferably equal to or less than 180 mg / kg. The solubility in water can be determined by coulometric Karl Fischer titration according to ASTM D6304.

[0051] According to some preferred embodiments, the organic solvent according to the present invention can be chosen from anisole derivatives such as l-ethyl-4-methoxybenzene, 2,6-dimethylanisole, cresol derivatives, xylenol derivatives, phenyl ether derivatives such as phenylpropyl ether and their combinations.

[0052] The organic solvent of formula (I) may be present in the working solution in an amount of 70 to 99.9% by weight, and preferably 80 to 99% by weight. For example, the organic solvent of formula (I) may be present in the working solution in an amount of 70 to 75% by weight; or 75 to 80% by weight; or 80 to 85% by weight; or 85 to 90% by weight; or 90 to 95% by weight; or 95 to 99.9% by weight.

[0053] According to some embodiments, the working solution comprises a unique organic solvent of formula (I).

[0054] Alternatively, the working solution comprises a mixture of organic solvents of formula (I) (for example two or three or four organic solvents of formula (D).

[0055] Furthermore, the working solution further comprises a quinone, preferably an anthraquinone and more preferably chosen from an alkylanthraquinone or a tetrahydroalkylanthraquinone, which is solubilized in the organic solvent of formula (I). By "quinone" or "quinone derivatives" is meant a class of organic compounds having a benzene ring on which two hydrogen atoms are replaced by two oxygen atoms forming two carbonyl bonds.

[0056] For the sake of simplicity, the term "alkylanthraquinone" used in the description below shall include both alkylanthraquinones and tetrahydroalkylanthraquinones.

[0057] Preferred alkyl substituents for alkylanthraquinones include amyl groups such as 2-tert-amyl or 2-iso-sec-amyl, ethyl, isopropyl, n-butyl, sec-butyl, tert-butyl and 2-hexenyl, and it is particularly preferred to include anthraquinones and / or tetrahydroanthraquinones at least with ethyl substitution. Thus, preferred alkylanthraquinones include 2-ethylanthraquinone, 2-isopropylanthraquinone, 2-n-butylanthraquinone, 2-sec-butylanthraquinone, 2-tert-butylanthraquinone, 2-amylanthraquinone, 2-sec-amylanthraquinone, 2-tert-amylanthraquinone, or mixtures thereof, as well as 2-alkyl-5,6,7,8-tetrahydroanthraquinones and mixtures thereof. corresponding 2-alkylanthraquinones. According to a preferred embodiment, the alkylanthraquinone may be 2-ethylanthraquinone.

[0058] Quinone may be present in the working solution in an amount of 0.1 to 30% by weight, and preferably from 1 to 20% by weight. For example, quinone may be present in the working solution in an amount of 0.1 to 1% by weight; or from 1 to 5% by weight; or from 5 to 10% by weight; or from 10 to 15% by weight; or from 15 to 20% by weight; or from 20 to 25% by weight; or from 25 to 30% by weight.

[0059] According to some embodiments, the working solution comprises a single quinone.

[0060] Alternatively, the working solution comprises a mixture of quinones (for example two or three or four quinones).

[0061] The working solution according to the invention may further comprise an additional solvent different from the organic solvent of formula (I). This additional solvent may be a solvent for solubilizing the quinone or a solvent for solubilizing the hydroquinone (formed after hydrogenation of the quinone). One or more additional solvents may be present in the working solution. For example, a first additional solvent for solubilizing the quinone and a second additional solvent for solubilizing the hydroquinone may be present in the working solution.

[0062] The additional solvent may be present in the working solution in a mass ratio with respect to the organic solvent of formula (I) in the range of 0:1 to 3:1, preferably in the range of 0:1 to 2:1 and more preferably in the range of 0:1 to 1:1.

[0063] Alternatively, the working solution according to the invention is free of any additional solvent. For example, the working solution may consist of (or essentially consist of) the organic solvent of formula (I) and the quinone.

[0064] In the case where the additional solvent is intended for the solubilization of the quinone (quinone solvent), this solvent may be a nonpolar hydrocarbon preferably chosen from aromatic, aliphatic or naphthenic hydrocarbons, among aromatic hydrocarbons are preferred above all others. Preferred solvents of this type include benzene, alkylated or polyalkylated benzenes such as tert-butylbenzene or trimethylbenzene, and alkylated toluenes or naphthalenes such as tert-butyltoluene or methylnaphthalene. The use of a commercial mixture of aromatic compounds marketed as Aromatic Solvent 150 (also known as CIO solvent) is possible. Aromatic Solvent 150 has the CAS number 64742-94-5 and is manufactured by distilling aromatic streams derived from petroleum products. It is also known by other brand names such as Solvent Naphtha 150, Solvesso 150, Caromax 150, Shellsol A150, and Heavy Aromatic Solvent Naphtha 150.

[0065] In the case where the additional solvent is intended for the solubilization of hydroquinone (solvent for hydroquinone), this solvent may be a polar organic solvent preferably insoluble in water. Such a solvent may be chosen from alcohols, ureas, amides, caprolactams, esters, phosphorus-containing substances and pyrrolidones, and may include alkyl phosphates (e.g. trioctyl phosphate), alkyl phosphonates, alkylcyclohexanol esters (e.g. 2-methylcyclohexyl acetate), N,N-dialkylcarbonamides, tetraalkylureas (e.g. tetrabutylurea), N-alkyl-2-pyrrolidones and high-boiling-point alcohols, preferably with 8 to 9 carbon atoms (e.g. diisobutylcarbinol). Preferred hydroquinone solvents are chosen from alkyl phosphates, tetraalkylureas, alkylcyclohexanol esters, and high-boiling-point alcohols.

[0066] Process for the production of hydrogen peroxide

[0067] The invention relates to a process for producing hydrogen peroxide by the AO process. Such a process comprises alternating steps of hydrogenation and oxidation of the working solution described above.

[0068] The hydrogenation step can be carried out by contacting the working solution with hydrogen gas. During this step, the quinone is hydrogenated to form the corresponding hydroquinone. This step is carried out in the presence of a catalyst. Such a catalyst can, for example, be a metal selected from nickel, palladium, platinum, rhodium, ruthenium, gold, silver, or mixtures thereof. Preferred metals are palladium, platinum, and gold, among which palladium or mixtures comprising at least 50% by weight of palladium are particularly preferred.

[0069] According to some embodiments, the catalyst can be either in a free form, for example palladium black suspended in the working solution, or deposited on a solid support such as particles used in the form of a suspension or a fixed bed.

[0070] According to other preferred embodiments, the catalyst may be in the form of an active metal on a monolithic support, for example, as described in US patents 4,552,748 and 5,063,043.

[0071] Preferred support materials may be selected from alumina, silica, aluminosilicates (silica-alumina), activated magnesia, titanium dioxide, carbon black, activated carbon, zeolites, ion-exchange resins, polymer substrates, metallic substrates, an alkaline earth metal carbonate or similar materials, or combinations thereof. The percentage concentration of the metal in the supported catalysts may be in the range of 0.1 to 50% by weight, but is preferably in the range of 0.2 to 5% by weight.

[0072] The hydrogenation step can be carried out at a temperature of 20 to 120 °C, and preferably from 30 to 90 °C.

[0073] Moreover, such a step can be carried out at an absolute pressure of 100 to 1200 kPa, and preferably from 150 to about 600 kPa.

[0074] Preferably, the hydrogenation step can be carried out either in a suspension reactor or in a fixed bed reactor.

[0075] After the hydrogenation step, the working solution (now containing hydroquinone) undergoes an oxidation step. During this step, the hydroquinone is converted to a quinone, while hydrogen peroxide is produced. This step is carried out in the presence of oxygen. Molecular oxygen, an oxygen-enriched gas, air, or any other suitable oxygenated compound suitable for producing hydrogen peroxide and oxidizing hydroquinone can be used as the oxygen source.

[0076] This step can be carried out, for example, in a bubble reactor, in which the oxygen source and the working solution can flow in co-current or counter-current fashion. The bubble reactor may be free of internal devices or preferably contain internal devices in the form of packing plates or sieves.

[0077] The oxidation step can be carried out at a temperature of 20 to 100 °C, and preferably from 40 to 75 °C.

[0078] Moreover, such a step can be carried out at an absolute pressure of 50 to 1,500 kPa, and preferably from 100 to about 700 kPa.

[0079] The oxidation step is preferably carried out with an excess of oxygen, so that preferably more than 90%, in particular more than 95%, of the hydroquinone contained in the working solution is converted into the quinone form.

[0080] At the end of this step, the working solution may have a hydrogen peroxide concentration of 0.5 to 2.5% by weight and preferably 0.8 to 1.9% by weight. For example, the working solution may have a hydrogen peroxide concentration of 0.5 to 1% by weight; or 1 to 1.5% by weight; or 1.5 to 2% by weight. weight; or 2 to 2.5% by weight.

[0081] After this step, the process according to the present invention may include a step of recovering hydrogen peroxide from a crude hydrogen peroxide solution. This step may be carried out by extracting the working solution resulting from the oxidation step with water. This step may be carried out in perforated tray extraction columns, packed columns, pulsed packed columns, and liquid-liquid centrifugal extractors.

[0082] The efficiency of the extraction is strongly influenced by the distribution coefficient, which depends on the composition of the working solution (for example, the type and concentration of solvents and the accumulation of degraded compounds). An efficient extraction can remove more than 95% of the hydrogen peroxide from the working solution.

[0083] At the end of this step, the crude hydrogen peroxide solution can have a hydrogen peroxide concentration of 25 to 55% by weight and preferably of 30 to 50% by weight.

[0084] The solution resulting from the recovery of hydrogen peroxide (and comprising the organic solvent of formula (I) and the quinone) can then be reused in the hydrogenation step. However, it is preferable, before reusing said solution in the hydrogenation step, to adjust its water content. Since the solubility of water in the working solution depends on the temperature, its moisture content can be adjusted by carrying out the extraction step at temperatures compatible with the extraction performance, separating the dispersed water, and then increasing the temperature of the working solution before it reaches the hydrogenation step. The working solution can also be dried using the exhaust gas from the oxidation step.Alternatively, the working solution leaving the extraction column can initially be cleared of entrained water in a water separator and then passed through an aqueous potassium carbonate solution for drying.

[0085] The fact that the organic solvent according to the invention has a water solubility equal to or less than 200 mg / kg reduces the loss of organic solvent during extraction. Furthermore, such reduced water solubility for the organic solvent allows for a higher purity crude hydrogen peroxide solution.

[0086] On the one hand, after the extraction step, the crude hydrogen peroxide solution can be treated (washed) to remove impurities such as entrained droplets of working solution and dissolved organic matter. This treatment can include, for example, coalescence, liquid-liquid extraction, treatment with resins, or any other treatment well known in the chemical industry. The purified crude product can then be introduced into a distillation unit, where it can to be further purified and concentrated to the usual commercial concentration (e.g. 50 to 70% by weight of hydrogen peroxide).

[0087] On the other hand, the working solution after the extraction step can be recycled to the hydrogenation step to continue the hydrogen peroxide production cycle. As degradation products form (from the quinone / hydroquinone compounds and solvents), the working solution should preferably be treated / regenerated to prevent deterioration in process performance. Numerous methods have been suggested for purifying the working solution and regenerating the active quinone from the quinone degradation products. For example, treatment with alkaline substances (aqueous solution of sodium hydroxide or potassium hydroxide, calcium hydroxide, ammonia, or amines), treatment with aluminum and sodium silicates, and extraction with active aluminum oxide.The working solution should also preferably be washed (usually with slightly acidic water) before being returned to the process. Examples

[0088] The following examples illustrate the invention without limiting it.

[0089] Example 1

[0090] In this example, 2-ethylanthraquinone (2-EAQ) was solubilized in four different solvents. Solvents A to C are according to the invention, while solvent D is a comparator solvent. - Solvent A: 1-ethyl-4-methoxybenzene - Solvent B: 2,6-dimethylanisole - Solvent C: phenylpropyl ether - Solvent D: 1,3,5-trimethylbenzene

[0091] The following table contains information on solvents A to D (at T = 20 °C).

[0092] Solubilities were determined by equilibrating 2-ethylanthraquinone with the solvent in a shaken glass flask under a carefully temperature-controlled atmosphere. Sample analysis was performed by liquid chromatography. Reference mixtures were prepared for calibration.

[0093] The boiling point or distillation range can be determined by manual or automatic distillation procedures in accordance with ASTM-D1078.

[0094] The flash point can be determined by a closed crucible apparatus according to ASTM-D3278.

[0095] Specific density can be determined using a hydrometer according to ASTM-D891.

[0096] Vapor pressure can be determined by ebulliometry according to ASTM-E1719.

[0097] Solubility in water can be determined by Karl Fischer coulometric titration according to ASTM-D6304. [Tables 1] Solvent ABCD Boiling Point (°C) 195.5-203 182.5-189.7 189.9-205.3 164.7 Flash Point (°C) 68-72 61-67 64-65 44-47 Specific Gravity 0.944 0.943 0.946 0.861 Vapor Pressure (Pa) 67 124 60 250 Solubility of 2-EAQ (g / kg of solvent) @ T = 20 °C 229 226 229 210

[0098] From the table above, it can be concluded that the organic solvents according to the present invention (A to C) are better for solubilizing 2-EAQ compared to the comparative solvent D.

Claims

Demands

1. A process for the production of hydrogen peroxide by the AO process comprising the two alternating steps of: - hydrogenation of a working solution in the presence of a catalyst, said working solution containing at least one quinone dissolved in at least one organic solvent, to obtain at least one corresponding hydroquinone; and - oxidation of said at least one hydroquinone; characterized in that the organic solvent corresponds to the formula (I): (I) R'-O-R2 in which: - R1 is an aryl group comprising from 6 to 18 carbon atoms; and - R2 is an alkyl group comprising from 1 to 8 carbon atoms, where R2 is a methyl group, R1 is not a phenyl.

2. A process according to claim 1, wherein the organic solvent has a specific density equal to or less than 0.

95.

3. A process according to any one of claims 1 to 2, wherein the organic solvent has a vapor pressure equal to or less than 450 Pa at 20 °C.

4. A process according to any one of claims 1 to 3, wherein the organic solvent has a solubility in water equal to or less than 200 mg / kg.

5. A method according to any one of claims 1 to 4, wherein the organic solvent of formula (I) has a flash point above 60 °C.

6. A process according to any one of claims 1 to 5, wherein R1-O- is derived from a phenol selected from o-cresol, m-cresol, p-cresol, o-ethylphenol, m-ethylphenol, p-ethylphenol, o-propylphenol, m-propylphenol, p-propylphenol, 2,6-dimethylphenol, 2,4-dimethylphenol, 3,4-dimethylphenol, or from a naphthol selected from 1-naphthol and 2-naphthol, and / or wherein R2 is a group selected from a methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, t-butyl, n-pentyl, neopentyl and n-hexyl.

7. A method according to any one of claims 1 to 6 wherein the quinone is an anthraquinone, more preferably an alkylan-thraquinone and / or a tetrahydroalkylanthraquinone, preferably selected from 2-ethylanthraquinone, 2-isopropylanthraquinone, 2-n-butylanthraquinone, 2-sec-butylanthraquinone, 2-tert-butylanthraquinone, 2-amylanthraquinone, 2-sec-amylanthraquinone, 2-tert-amylanthraquinone or mixtures thereof.

8. A process according to any one of claims 1 to 7, wherein the working solution further comprises an additional solvent selected from alkyl phosphates, tetraalkylureas, alkylcyclohexanol esters, alcohols comprising 8 to 9 carbon atoms and mixtures thereof.

9. A process according to any one of claims 1 to 7, wherein the working solution consists of the organic solvent of formula (I) and quinone.

10. Use of an organic solvent for dissolving a quinone in a working solution for the production of hydrogen peroxide, wherein the organic solvent corresponds to the formula (I): (I) R'-O-R2 in which: - R1 is an aryl group comprising from 6 to 18 carbon atoms; and - R2 is an alkyl group comprising from 1 to 8 carbon atoms, where R2 is a methyl group, R1 is not a phenyl.