Method for producing compounds containing aromatic polyhydroxy compounds

Abstract

To provide a production method of a compound including an aromatic polyhydroxy compound capable of separating to an oil phase and an aqueous phase by reacting phenol in the presence of a catalyst using hydrogen peroxide and alcohol together, subjecting a reaction mixture to precipitation in a catalyst-separating process at a comparatively high temperature to separate titanosilicate, which is a catalyst, and making an obtained oil water phase an oil-water separable state by cooling to a comparatively low temperature.SOLUTION: A production method of a compound including an aromatic polyhydroxy compound includes: reacting titanosilicate, alcohol, water, an aromatic monohydroxy compound, and hydrogen peroxide to obtain a reaction mixture (R); and thereafter conducting following process (1), and process (2), where the process (2) is conducted after the process (1). The process (1) is a process of precipitating the titanosilicate from the reaction mixture (R) at a temperature of 50°C or higher. The process (2) is a process of separating a compound including an aromatic polyhydroxy compound from an oil phase by subjecting a liquid part (reaction mixture (R1)) of the process (1) to oil-water separation at a temperature of 28°C or higher and 48°C or lower.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an industrial production method of a compound containing an aromatic polyhydroxy compound, which uses titanosilicate as a catalyst, reacts phenols with hydrogen peroxide, and performs a catalyst separation step, a cooling step, and an oil-water separation step on the obtained reaction solution.

Background Art

[0002] Aromatic dihydroxy compounds are used in fields such as reducing agents, rubber chemicals, dyes, pharmaceuticals, agricultural chemicals, polymerization inhibitors, and oxidation inhibitors. Hydroquinone and catechol are aromatic dihydroxy compounds obtained by reacting phenols with hydrogen peroxide, and the production ratios of hydroquinone and catechol differ depending on the production method. In recent years, due to the supply-demand balance of hydroquinone and catechol, a method for highly selectively producing hydroquinone has been eagerly desired.

[0003] In the method of obtaining hydroquinone by reacting phenol with hydrogen peroxide, the present applicant has reported that the selectivity of hydroquinone is improved by reacting in the presence of titanosilicate, an alcohol having a tertiary or quaternary carbon and having 4 to 5 carbon atoms, and 5 to 90% by mass of water and / or methanol based on the total mass of the reaction solution (Patent Document 1).

[0004] Also, in the presence of metal ions, directly oxidizing phenol with hydrogen peroxide in an acidic aqueous solution to produce hydroquinone, extracting phenols with an organic solvent, and circulating and using the extracted aqueous phase as a reaction medium is a method known from Patent Document 2. The recycling of this extracted aqueous phase is important from the viewpoints of reducing environmental load by suppressing wastewater discharge and saving water resources. However, in actual situations, problems such as difficulty in liquid separation during extraction may occur as described in Patent Document 3.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] Against this background, the inventors investigated the production of hydroquinone and found that while it is preferable to separate the titanosilicate, the catalyst in the aforementioned reaction process, and reuse it in the reaction, in reaction solutions such as those described in Patent Document 1, solid substances may not settle easily, or oil-water separation may be difficult, resulting in a completely unexpected situation where industrially efficient production is difficult. This was thought to be probably due to the presence of alcohol. [Means for solving the problem]

[0007] This invention has found that by reacting phenols with hydrogen peroxide, the reaction solution can be separated by sedimentation of the catalyst, titanosilicate, at a relatively high temperature in a catalytic separation step, and the resulting oil-water phase can be cooled to a relatively low temperature to make it possible to separate the oil and water phases. In other words, this invention is defined by the following requirements.

[0008] [1] Titanosilicate, alcohol, water, aromatic monohydroxy compound, and hydrogen peroxide are reacted to obtain a reaction solution (R), after which steps 1 and 2 below are carried out. Step 2 is performed after step 1. A method for producing compounds containing aromatic polyhydroxy compounds. Step 1: A step of allowing the titanosilicate to settle in the reaction solution (R) at a temperature of 50°C or higher. Step 2: The liquid portion (reaction solution (R1)) from Step 1 is separated into oil and water at a temperature of 28°C or higher and 48°C or lower, and compounds containing aromatic polyhydroxy compounds are separated from the oil phase.

[0009] [2] The compound manufacturing method according to [1], wherein the difference between the temperature (1) of step 1 and the temperature (2) of step 2 is 10 to 52°C.

[0010] [3] The method for producing a compound according to [1], wherein the temperature (1) of step 1 is 55°C to 80°C.

[0011] [4] The compound manufacturing method according to [1], wherein the temperature (2) of step 2 is 28°C to 45°C. [Effects of the Invention]

[0012] The manufacturing method of the present invention can suppress the proportion of catalyst outflow into the oil-water phase during the catalyst sedimentation separation process, thereby reducing catalyst loss and contributing to a reduction in the manufacturing cost of compounds containing aromatic polyhydroxy compounds, particularly aromatic dihydroxy compounds. Furthermore, in the oil-water separation process, it is possible to reduce the distribution ratio of the water phase to the oil phase supplied to the distillation process, thereby reducing steam costs. [Modes for carrying out the invention]

[0013] As described above, the present invention is a method for producing a compound containing an aromatic polyhydroxy compound, characterized by performing step 1 of reacting titanosilicate, alcohol, water, an aromatic monohydroxy compound, and hydrogen peroxide to obtain a reaction solution (R), followed by step 2 of separating the catalyst by sedimentation at a relatively high temperature, and then performing oil-water separation of the reaction solution after catalyst separation at a relatively low temperature.

[0014] Examples of aromatic monohydroxy compounds used in the present invention include phenols, specifically unsubstituted phenols and substituted phenols. Here, substituted phenols include alkylphenols substituted with linear or branched alkyl or cycloalkyl groups having 1 to 6 carbon atoms, such as methyl groups, ethyl groups, isopropyl groups, butyl groups, and hexyl groups.

[0015] More specific examples of phenols include phenol, 2-methylphenol, 3-methylphenol, 2,6-dimethylphenol, 2,3,5-trimethylphenol, 2-ethylphenol, 3-isopropylphenol, 2-butylphenol, and 2-cyclohexylphenol, but phenol is particularly preferred. Furthermore, if phenols have substitution values ​​at both the 2nd and 6th positions, in principle, the product is often only a hydroquinone derivative.

[0016] Specific examples of compounds containing aromatic polyhydroxy compounds as reaction products include hydroquinones (substituted or unsubstituted hydroquinones) and catechols (substituted or unsubstituted catechols). More specifically, examples include hydroquinone, catechol, 2-methylhydroquinone, 3-methylcatechol, 4-methylcatechol, 3-methylhydroquinone, 1,4-dimethylhydroquinone, 1,4-dimethylcatechol, 3,5-dimethylcatechol, 2,3-dimethylhydroquinone, and 2,3-dimethylcatechol.

[0017] The present invention can be implemented using any of the following methods: batch, semi-batch, or continuous flow. Various methods can be used for catalyst packing, such as fixed bed, fluidized bed, suspension bed, or shelf-type fixed bed, and any of these methods may be used.

[0018] In this invention, the total mass of the reaction solution refers to the total mass of the liquid components in the reaction system. That is, it does not include the mass of solid components such as titanosilicate. The liquid components in the reaction system include phenols, hydrogen peroxide, C4-C5 alcohols having tertiary or quaternary carbons, water and / or methanol, aromatic polyhydroxy compounds, and reaction by-products. Other solvents may be included as needed, to the extent that they do not impair the effects of this invention. As the reaction progresses, the amount of reaction product increases, but the total mass of the reaction solution during the reaction remains substantially constant.

[0019] The composition of the titanosilicate used as a catalyst in this invention is (SiO2) ·(TiO2) (1-x) refers to those having the structure shown. In this case, the value range of x / (1 - x) is 5 to 1,000, preferably 10 to 500. The titanosilicate can be produced by known methods. For example, as described in US Patent No. 4,410,501 and Catalysis Today 147(2009)186 - 195, a hydrothermal synthesis method of silicon alkoxide and titanium alkoxide in the presence of a quaternary ammonium salt or the like is common. When the quaternary ammonium salt used is a tetrapropylammonium salt, the resulting titanosilicate has an MFI structure and is preferably used. Also, for the MFI type titanosilicate, (SiO2) x ·(TiO2) (1-x) as long as it is within a predetermined range, commercially available ones can be used without any problem.

[0020] Also, the titanosilicate catalyst may be used as it is, or it may be molded and used according to the catalyst filling method. As the catalyst molding method, extrusion molding, tableting molding, rolling granulation, spray granulation, etc. are common. When using the catalyst in a fixed bed system, extrusion molding or tableting molding is preferred. In the case of a suspension bed system, spray granulation is preferred. For example, as described in US Patent No. 4,701,428, a method of mixing a previously prepared titanosilicate suspension and a silica raw material and performing spray granulation using a spray dryer is common. As the silica raw material, silicon alkoxide, colloidal silica, dissolved silica in water, sodium silicate (water glass), potassium silicate, etc. can be used. However, since the inclusion of metal impurities other than silicon has an adverse effect on the catalyst performance, silicon alkoxide, colloidal silica, and dissolved silica in water with few impurities are preferred. Also, drying or firing may be performed after spray granulation. The average particle size of the spray granulated molded catalyst is preferably in the range of 0.1 μm to 1,000 μm, more preferably 5 μm to 100 μm. It is preferably 0.1 μm or more because it is easy to handle such as filtering the catalyst, and it is preferably 1,000 μm or less because the catalyst has good performance and high strength.

[0021] The amount of the titanosilicate catalyst used is preferably in the range of 0.1 to 30% by mass, more preferably 0.4 to 20% by mass, based on the total mass of the reaction solution. When it is 0.1% by mass or more, the reaction is completed in a short time and productivity is improved, which is preferable. When it is 30% by mass or less, it is preferable in terms of the small amount of catalyst separation and recovery.

[0022] Hydrogen peroxide is preferably in a molar ratio of 0.01 or more and 1 or less with respect to phenols. The concentration of hydrogen peroxide used is not particularly limited, and an ordinary 30% aqueous solution may be used, or a higher concentration hydrogen peroxide solution may be used as it is or diluted with a solvent inert in the reaction system. Examples of the solvent used for dilution include alcohols and water. Hydrogen peroxide may be added at once or gradually added over time.

[0023] Examples of the alcohol having a tertiary or quaternary carbon and having 4 to 5 carbon atoms used in this reaction include tertiary butyl alcohol, 2-methyl-1-propanol, 2-methyl-1-butanol, 3-methyl-1-butanol, 2,2-dimethyl-1-propanol, 2-methyl-2-butanol, 3-methyl-2-butanol, etc. Among them, particularly preferred are tertiary butyl alcohol, 2,2-dimethyl-1-propanol, and 2-methyl-2-butanol. Among them, particularly tertiary butyl alcohol is preferable because it can be separated from water and is easy to recover. When such alcohols are included, the selectivity of hydroquinones can be increased. The amount of the alcohol having a tertiary or quaternary carbon and having 4 to 5 carbon atoms used is preferably in the range of 1 to 90% by mass, more preferably 3 to 50% by mass, based on the total mass of the reaction solution. When it is 1% by mass or more, it is preferable in terms of the high selectivity of hydroquinones, and when it is 90% by mass or less, it is preferable in terms of the high reaction rate and the small amount of solvent recovery.

[0024] In the present invention, water and / or methanol may be either water or methanol, or water and methanol may be used in any ratio. Considering the recovery and reuse of the solvent, the use of water alone is preferred. The water may also be water contained in hydrogen peroxide solution. The amount of water and / or methanol is preferably in the range of 5 to 90% by mass, more preferably in the range of 8 to 90% by mass, and even more preferably in the range of 8 to 85% by mass, relative to the total mass of the reaction solution. Considering the recovery of the solvent, the use of water alone is preferred, and the amount of water used is preferably in the range of 8 to 85% by mass relative to the total mass of the reaction.

[0025] Furthermore, the reaction raw materials (phenols, hydrogen peroxide) contained in the reaction solution are preferably in the range of 10 to 94% by mass, more preferably 13 to 80% by mass. Within this range, the manufacturing method of the present invention can efficiently produce compounds containing the desired aromatic polyhydroxy compound.

[0026] The ratio (by mass) of C4-C5 alcohols having tertiary or quaternary carbons to water and / or methanol is preferably in the range of 1:99 to 90:10, more preferably 3:97 to 80:20, for C4-C5 alcohols having tertiary or quaternary carbons to water and methanol. Considering solvent recovery, it is preferable to use only water excluding methanol, and the ratio (by mass) of C4-C5 alcohols having tertiary or quaternary carbons to water is preferably in the range of 3:97 to 80:20. With this ratio, the yield of compounds containing aromatic polyhydroxy compounds is high, and the selectivity of hydroquinones is high.

[0027] The reaction temperature is preferably in the range of 30°C to 130°C, more preferably in the range of 40°C to 100°C. The reaction will proceed at temperatures outside this range, but the above range is preferred from the viewpoint of improving productivity. The reaction pressure is not particularly limited.

[0028] This reaction may be carried out in batches, semi-batches, or continuously. If carried out continuously, it may be done in a suspension-type homogeneous mixing tank or in a fixed-bed flow-type plug-flow system. Multiple reactors may also be connected in series and / or parallel. From the standpoint of equipment costs, 1 to 4 reactors are preferable. When using multiple reactors, hydrogen peroxide may be added to them in divided portions.

[0029] This reaction is typically carried out in a suspension bed and includes a step of separating the catalyst from the resulting reaction solution (R). Generally, sedimentation separation, centrifugal filtration, pressure filtration, filter press, leaf filter, and rotary filter are used for catalyst separation, but in this invention, sedimentation separation is used. Sedimentation separation is particularly preferable from an economic standpoint because it does not require expensive filtration equipment compared to various other filtration methods. In sedimentation separation, the oil-water phase is usually withdrawn from the top by overflow, and the catalyst, which has settled along with some of the water phase, is withdrawn from the bottom. At this time, an emulsion phase may form in the reaction solution (R), and the catalyst may become mixed into this emulsion phase. In such cases, the catalyst may flow out into the liquid phase withdrawn from the top, reducing the catalyst recovery rate.

[0030] In the present invention, the reaction solution (R) is heated to 50°C or higher to separate the catalyst by sedimentation (Step 1). By performing Step 1, the sedimentation of the catalyst is promoted, and the catalyst can be efficiently separated from the emulsion phase. The preferred lower limit of the temperature in Step 1 is 55°C, more preferably 60°C. On the other hand, the preferred upper limit of the temperature in Step 1 is 100°C, more preferably 90°C, and even more preferably 80°C.

[0031] The reason why the catalyst settles at such temperatures is unclear, but the inventors speculate as follows. The aforementioned catalyst is thought to have an affinity for alcohols and other substances, and is likely to readily form emulsions. On the other hand, within the temperature range mentioned above, the affinity for alcohols and other substances decreases, and it is conceivable that the catalyst solid may be more prone to settling due to the influence of its own density.

[0032] When the reaction is carried out continuously, the liquid phase is continuously withdrawn. If the catalyst is withdrawn as a cake or powder rather than a suspension, it may be reused in the reaction as is, or it may be dried (also called regeneration) before reuse. For drying, box dryers, band dryers, rotary dryers, spray dryers, and airflow dryers can be used. Drying can be carried out under an inert gas atmosphere such as nitrogen, an air atmosphere, an air atmosphere diluted with an inert gas, a water vapor atmosphere, or a water vapor atmosphere diluted with an inert gas. The drying temperature is preferably 60-800°C, and particularly preferably 80-600°C. At this temperature, the amount of attached organic matter can be reduced without significantly impairing the performance of the catalyst. Furthermore, the treatment can be carried out by combining multiple different temperature ranges. Furthermore, in order to obtain the dihydroxy compound from the above reaction solution, the separated liquid (R1) containing the dihydroxy compound after separating the reaction solution or catalyst may be subjected to a purification treatment, such as removing unreacted components or by-products. This purification treatment can be more preferably used for the separated liquid containing the dihydroxy compound after separating the catalyst. There are no particular restrictions on the purification treatment method, and specific examples include oil-water separation, extraction, distillation, crystallization, and combinations thereof. There are no particular restrictions on the purification treatment method or procedure, but for example, the separated liquid containing the dihydroxy compound after separating the reaction solution and catalyst can be purified by the following method.

[0033] When the reaction solution separates into two phases, an oil phase and an aqueous phase, oil-water separation is possible. By oil-water separation, the aqueous phase, which has a low content of dihydroxy compounds, is removed, and the oil phase is recovered. In this case, the separated aqueous phase may be used again in the reaction, either to recover the dihydroxy compounds by extraction or distillation, or partially or entirely. Alternatively, the catalyst separated in the catalyst separation step or the catalyst that has been dried can be dispersed in the separated aqueous phase and supplied to the reactor. On the other hand, it is desirable to further purify the oil phase by extraction, distillation, crystallization, etc.

[0034] Regarding oil-water separation after catalytic sedimentation, if the temperature remains the same as in step 1, an emulsion phase may form or the oil and water may become a homogeneous phase, making separation of the oil and water phases difficult. As a method to suppress the formation of the emulsion phase, the liquid temperature should be between 28°C and 48°C. A preferred lower limit is 30°C. On the other hand, as the liquid temperature increases, the distribution ratio of the water phase to the oil phase increases, which becomes a burden in the distillation of the oil phase in the next step. As a method to reduce the distribution ratio of the water phase to the oil phase, a preferred upper limit is 45°C, and more preferably 40°C. After setting the temperature within this range, oil-water separation is performed (step 2). At this time, it is preferable to make the temperature distribution of the obtained liquid phase as uniform as possible by methods such as stirring or shaking.

[0035] Oil-water separation may be performed directly in the catalytic sedimentation tank, but a temperature control tank may be provided after the catalytic sedimentation tank to adjust the liquid temperature. The most desirable configuration is to separate the catalyst by sedimentation, then adjust the liquid temperature in the temperature control tank before transferring it to the oil-water separation tank.

[0036] Furthermore, it is also possible to carry out steps 1 and 2 in succession. As described above, the present invention is characterized by the fact that by performing steps 1 and 2 in this order, catalyst (solid) separation and oil-water separation can be efficiently carried out.

[0037] The oil phase obtained by carrying out steps 1 and 2 above contains the target substances, such as dihydroxy compounds and diketone compounds. From this, the target substances can be separated using known methods such as concentration or distillation. (If diketone compounds become dominant in the above reaction, the present invention can also be applied to a method for producing diketone compounds.)

[0038] As described above, in the present invention, the temperature ranges for Step 1 and Step 2 are different (Step 1 is carried out at a higher temperature). A relatively large temperature difference between Step 1 and Step 2 tends to make it easier to obtain the effects of the present invention. Preferably, this temperature difference is in the range of 10 to 52°C. A more preferable lower limit is 15°C, and even more preferable is 20°C. On the other hand, a more preferable upper limit is 50°C, and even more preferable is 45°C.

[0039] Distillation may be carried out on the reaction solution immediately after catalyst separation, or on the oil and aqueous phases after oil-water separation. The extract may also be further distilled.

[0040] When distilling the reaction solution immediately after catalyst separation, it is preferable to first separate light-boiling components such as water and alcohols. Water and alcohols may be separated in separate distillation columns or in a single distillation column. In this invention, it is desirable to simultaneously separate water, methanol, and C4-C5 alcohols having tertiary or quaternary carbons by distillation.

[0041] The water, methanol, and C4-C5 alcohols having tertiary or quaternary carbons, separated into the aqueous or oil phase, may be partially or entirely reused in the reaction. Alternatively, the catalyst separated in the catalyst separation step or the dried catalyst can be dispersed in the separated water, methanol, and C4-C5 alcohols having tertiary or quaternary carbons and supplied to the reactor.

[0042] After separating water and alcohols by the aforementioned oil-water separation, extraction, and distillation operations, the phenols may be recovered by the next distillation operation and reused in the reaction. If the recovered phenols contain water that could not be separated, isopropyl ether or toluene can be added and removed by azeotropic distillation. This azeotropic distillation can also be performed on the water before phenol recovery or on the liquid after alcohol separation. The separated water may be reused in the reaction or treated as wastewater. If the recovered phenols contain impurities other than water, such as reaction by-products, they can be further separated by distillation. If the impurities are benzoquinones, which are reaction by-products, they can be supplied back into the reactor together with the phenols.

[0043] After separating the phenols, components with higher boiling points than aromatic polyhydroxy compounds can be removed by distillation, and hydroquinones and catechols can be separated by the next distillation operation. Alternatively, the high-boiling components, hydroquinones, and catechols can be separated in a single distillation operation by withdrawing the hydroquinones from the middle of the distillation column.

[0044] The obtained hydroquinones and catechols can be purified by removing impurities through distillation or crystallization, if necessary, to increase their purity. Aromatic polyhydroxy compounds such as hydroquinone obtained in this way are useful as intermediates or raw materials for various organic synthesis and are used in fields such as reducing agents, rubber compounds, dyes, pharmaceuticals, agrochemicals, polymerization inhibitors, and oxidation inhibitors. [Examples]

[0045] The present invention will be described in more detail below with reference to examples, but the present invention is not limited thereto.

[0046] Yield of aromatic dihydroxy compound (%) = [(moles of hydroquinone produced) + (moles of catechol produced)] ÷ (moles of hydrogen peroxide added) × 100 Hydroquinone / catechol ratio = (moles of hydroquinone produced) ÷ (moles of catechol produced)

[0047] (Manufacturing Example 1) A 1L stainless steel autoclave equipped with an external heater, pressure gauge, thermometer, and stirring blade was charged with 25g of titanosilicate (TS-1) catalyst, 122g of phenol, 87g of tertiary butanol, and 221g of water. The autoclave was then pressurized to 0.3 MPaG using nitrogen. The contents of the autoclave were then stirred with the stirring blade while the internal temperature reached 90°C. Under these conditions, 35.4% by mass hydrogen peroxide solution was fed into the autoclave at a rate of 0.3g / min for 120 minutes. After cooling, the reaction mixture was sampled, and the remaining hydrogen peroxide was quantified by iodometry, and the product by gas chromatography. As a result, the yield of aromatic hydroxy compounds was 70%, and the hydroquinone / catechol ratio was 4.0.

[0048] [Analytical conditions for gas chromatography] Detector; Flame ionization detector (FID) Column; DB-5 (Agilent J&W), inner diameter 0.25 mm, length 60 m, film thickness 0.25 μm Column temperature: 50°C, heating rate: 5°C / min, heating to 300°C and holding for 10 minutes. Inlet temperature: 290℃ Detector temperature: 300℃ Carrier gas: Nitrogen Flow rate: 1mL / min.

[0049] (Comparative Example 1) A suspension solution obtained in Production Example 1, consisting of 25% by mass of phenol, 20% by mass of tert-butanol, 4% by mass of hydroquinone, 1% by mass of catechol, 5% by mass of titanosilicate catalyst, and 45% by mass of water, was continuously fed into a separable flask kept warm at a liquid temperature of 30°C, and catalyst sedimentation separation was performed. After separating the overflowed oil and water phases at 30°C, the weight and water concentration of each phase were measured. The water distribution ratio into the oil phase was calculated to be 20.9% by mass. Furthermore, the amount of catalyst from each overflowed phase was measured, and the efflux rate of the catalyst into the oil-water phase was calculated to be 1.0% by mass.

[0050] (Reference example 1) The suspension solution obtained in Production Example 1, consisting of 25% by mass of phenol, 20% by mass of tert-butanol, 4% by mass of hydroquinone, 1% by mass of catechol, 5% by mass of titanosilicate catalyst, and 45% by mass of water, was continuously fed into a separable flask kept warm at a liquid temperature of 50°C, and catalyst sedimentation separation was performed. After separating the overflowed oil and water phases at 50°C, the weight and water concentration of each phase were measured. The water distribution ratio into the oil phase was calculated to be 32.6% by mass. In addition, the amount of catalyst was measured from each overflowed phase, and the efflux rate of the catalyst into the oil-water phase was calculated to be 2.0% by mass.

[0051] (Example 2 (only step 1 is performed)) The suspension solution obtained in Production Example 1, consisting of 25% by mass of phenol, 20% by mass of tert-butanol, 4% by mass of hydroquinone, 1% by mass of catechol, 5% by mass of titanosilicate catalyst, and 45% by mass of water, was continuously fed into a separable flask kept warm at a liquid temperature of 70°C, and catalyst sedimentation separation was performed. After separating the overflowed oil and water phases at 70°C, the weight and water concentration of each phase were measured. The water distribution ratio into the oil phase was calculated to be 39.8% by mass. In addition, the amount of catalyst was measured from each overflowed phase, and the efflux rate of the catalyst into the oil-water phase was calculated to be 0.1%.

[0052] (Comparative Example 2) The suspension solution obtained in Production Example 1, consisting of 25% by mass of phenol, 20% by mass of tert-butanol, 4% by mass of hydroquinone, 1% by mass of catechol, 5% by mass of titanosilicate catalyst, and 45% by mass of water, was continuously fed into a separable flask kept warm at a liquid temperature of 70°C, and catalytic sedimentation separation was performed. When the oil and water phases that overflowed as part of the oil-water separation were allowed to stand at room temperature (around 25°C), the emulsion phase did not dissipate even after 240 minutes.

[0053] (Comparative Example 3) The suspension solution obtained in Example 1, consisting of 25% by mass of phenol, 20% by mass of tert-butanol, 4% by mass of hydroquinone, 1% by mass of catechol, 5% by mass of titanosilicate catalyst, and 45% by mass of water, was continuously fed into a separable flask that was kept warm to a liquid temperature of 70°C. The overflowing oil and aqueous phases were poured into a cooling tank and stirred and mixed under conditions of 20°C with an average residence time of 30 minutes. When the overflowing oil and aqueous phases were allowed to stand at room temperature, the time it took for the emulsion phase to dissipate was 44 minutes.

[0054] (Example 1) The suspension solution obtained in Production Example 1, consisting of 25% by mass of phenol, 20% by mass of tert-butanol, 4% by mass of hydroquinone, 1% by mass of catechol, 5% by mass of titanosilicate catalyst, and 45% by mass of water, was continuously fed into a separable flask kept warm at a liquid temperature of 70°C, and catalytic sedimentation separation was performed. The overflowing oil and water phases were flowed into a cooling tank and stirred and mixed under conditions of an average residence time of 30 minutes and 30°C. The overflowing oil and water phases were then flowed into an oil-water separation tank under conditions of an average residence time of 60 minutes and 30°C, and continuous oil-water separation was performed, resulting in good liquid-liquid separation. Subsequently, the target substance was separated by conventional methods of oil-water separation, concentration, and distillation.

[0055] (Comparative Example 4) The suspension solution obtained in Production Example 1, consisting of 25% by mass of phenol, 20% by mass of tert-butanol, 4% by mass of hydroquinone, 1% by mass of catechol, 5% by mass of titanosilicate catalyst, and 45% by mass of water, was continuously fed into a separable flask kept warm at a liquid temperature of 70°C. The overflowing oil and water phases were flowed into a cooling tank and stirred and mixed under conditions of an average residence time of 30 minutes and 20°C. The overflowing oil and water phases were then flowed into an oil-water separation tank under conditions of an average residence time of 30 minutes and 20°C, and continuous oil-water separation was performed, resulting in the formation of an emulsion, which increased over time.

[0056] (Comparative Example 5) The suspension solution obtained in Production Example 1, consisting of 25% by mass of phenol, 20% by mass of tert-butanol, 4% by mass of hydroquinone, 1% by mass of catechol, 5% by mass of titanosilicate catalyst, and 45% by mass of water, was continuously fed into a separable flask kept warm at a liquid temperature of 70°C. The overflowing oil and water phases were flowed into a cooling tank and stirred and mixed under conditions of an average residence time of 30 minutes and 25°C. The overflowing oil and water phases were then flowed into an oil-water separation tank under conditions of an average residence time of 30 minutes and 25°C, and continuous oil-water separation was performed. An emulsion was generated, and the emulsion phase slowly increased over time.

[0057] (Reference Example 3 (Step 2 is carried out using a simulated reaction solution)) A simulated solution consisting of 27.7% by mass of phenol, 19.8% by mass of tert-butanol, 1.5% by mass of hydroquinone, 0.5% by mass of catechol, and 50.5% by mass of water was placed in a pressure-resistant glass autoclave and stirred at over 50°C, resulting in an oil-water suspension. Further heating to 97°C homogenized the oil-water mixture.

[0058] (Reference Example 4 (Step 2 is carried out using a simulated reaction solution)) A simulated solution consisting of 27.2% by mass of phenol, 19.4% by mass of tert-butanol, 2.9% by mass of hydroquinone, 1.0% by mass of catechol, and 49.5% by mass of water was placed in a pressure-resistant glass autoclave and stirred at over 50°C, resulting in an oil-water suspension. Further heating to 88°C homogenized the oil-water mixture.

[0059] (Reference Example 5 (Step 2 is carried out using a simulated reaction solution)) A simulated solution consisting of 26.7% by mass of phenol, 19.1% by mass of tert-butanol, 4.2% by mass of hydroquinone, 1.4% by mass of catechol, and 48.6% by mass of water was placed in a pressure-resistant glass autoclave and stirred at over 50°C, resulting in an oil-water suspension. Further heating to 79°C homogenized the oil-water mixture.

Claims

1. Titanosilicate, alcohol, water, aromatic monohydroxy compound, and hydrogen peroxide are reacted to obtain a reaction solution (R), after which steps 1 and 2 below are carried out. The amount of titanosilicate used is 0.1 to 30% by mass of the total mass of the reaction solution (R). The amount of the aromatic monohydroxy compound contained in the reaction solution (R) is 13 to 80% by mass. Step 2 is performed after step 1. A method for producing compounds containing aromatic polyhydroxy compounds. Step 1: A step of allowing the titanosilicate to settle in the reaction solution (R) at a temperature of 55°C or higher. Step 2: The liquid portion (reaction solution (R1)) from Step 1 is subjected to oil-water separation at a temperature of 28°C or higher and 48°C or lower, and a compound containing an aromatic polyhydroxy compound is separated from the oil phase.

2. The compound production method according to claim 1, wherein the amount of titanosilicate used is 0.4 to 20% by mass of the total mass of the reaction solution (R).

3. The compound production method according to claim 1, wherein the difference between the temperature (1) of step 1 and the temperature (2) of step 2 is 10 to 52°C.

4. The compound production method according to claim 1, wherein the temperature (1) of step 1 is 55°C to 80°C.

5. The compound production method according to claim 1, wherein the temperature (2) of step 2 is 28°C to 45°C.