Method for producing cumene, apparatus for producing cumene, and method for producing propylene oxide

Abstract

This method for producing cumene comprises the steps (e) and (f) described below, and the stream (3) contains 20% by mass or more and 99% by mass or less of acetophenone and 1% by mass or more and 10% by mass or less of 2, 3-dimethyl-2, 3-diphenylbutane. And (e) a cumene conversion step of converting cumyl alcohol into cumene to obtain a solution (1) containing cumene, and taking the solution (1) as a material flow (1). And (f) a cumene purification step of separating the solution (1) of the stream (1) into at least a solution (2) containing purified cumene and a solution (3) containing 2, 3-dimethyl-2, 3-diphenylbutane, thereby obtaining a stream (2) containing purified cumene and a stream (3) containing 2, 3-dimethyl-2, 3-diphenylbutane.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the priority of Japanese Patent Application No. 2022-109786, which is incorporated by reference into the description of the present application specification. Technical Field

[0003] The present invention relates to a method for producing cumene, an apparatus for producing cumene and a method for producing propylene oxide. Background Art

[0004] Conventionally, there is known a method for producing propylene oxide through an oxidation step of oxidizing cumene to obtain cumene hydroperoxide, an epoxidation step of reacting the cumene hydroperoxide obtained in the oxidation step with propylene to obtain propylene oxide and cumyl alcohol, and a cumene conversion step of converting the cumyl alcohol obtained in the epoxidation step into cumene. In addition, it is known that in this production method, the cumene obtained in the cumene conversion step can be recycled to the oxidation step.

[0005] In the cumene conversion step of converting cumyl alcohol into cumene, part of cumene dimerizes and cumene dimers such as 2,3-dimethyl-2,3-diphenylbutane are incidentally generated. However, the stream containing the cumene dimer has the following problems: when transporting to the next step, the component containing the cumene dimer solidifies and clogs the pipeline.

[0006] In order to solve the above-mentioned problem, for example, Patent Document 1 discloses a method in which a diluent oil is added to and mixed with a stream containing cumene dimers and the temperature is maintained at 50°C.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent Application Publication No. 2003-40810 Summary of the invention

[0010] Problems to be solved by the invention

[0011] However, in the method of Patent Document 1, the fluidity of the stream containing cumene dimer (e.g., 2,3-dimethyl-2,3-diphenylbutane) is reduced at room temperature, although the fluidity is maintained at 50°C. In actual plant equipment, the temperature of the stream immediately after being discharged from the distillation tower is about 150°C, and then it is cooled to room temperature in the pipeline leading to the mixing equipment, waste oil combustion equipment, etc. Therefore, in the method of Patent Document 1, it is necessary to heat the pipeline leading to the next equipment.

[0012] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for producing cumene, a device for producing cumene, and a method for producing propylene oxide, in which a stream containing 2,3-dimethyl-2,3-diphenylbutane can maintain good fluidity even at room temperature.

[0013] Means used to solve problems

[0014] The method for producing cumene of the present invention comprises the following steps (e) and (f):

[0015] (e) Cumene conversion step: a step of converting cumyl alcohol into cumene to obtain a solution (1) containing cumene, which is used as a feed stream (1);

[0016] (f) a cumene purification step: a step of separating the solution (1) of the stream (1) into at least a solution (2) containing purified cumene and a solution (3) containing 2,3-dimethyl-2,3-diphenylbutane, thereby obtaining a stream (2) containing purified cumene and a stream (3) containing 2,3-dimethyl-2,3-diphenylbutane.

[0017] The stream (3) contains 20% by mass or more and 99% by mass or less of acetophenone and 1% by mass or more and 10% by mass or less of 2,3-dimethyl-2,3-diphenylbutane.

[0018] The cumene production device of the present invention is a device for producing cumene using the above-mentioned cumene production method, wherein:

[0019] The cumene production apparatus comprises a device A for separating the solution (1) of the stream (1) into at least a solution (2) containing purified cumene and a solution (3) containing 2,3-dimethyl-2,3-diphenylbutane.

[0020] The method for producing propylene oxide of the present invention is a method for producing propylene oxide comprising the method for producing cumene, wherein:

[0021] The method for producing propylene oxide comprises the following steps (a) to (f),

[0022] (a) Oxidation step: a step of oxidizing cumene to obtain cumene hydroperoxide;

[0023] (b) epoxidation step: a step of reacting the cumene hydroperoxide obtained in the above-mentioned (a) oxidation step with propylene to obtain a reaction mixture containing propylene oxide and cumyl alcohol;

[0024] (c) a separation step: a step of separating a mixture containing propylene oxide from the reaction mixture containing propylene oxide and cumyl alcohol obtained in the above-mentioned (b) epoxidation step to obtain a residue containing cumyl alcohol;

[0025] (d) propylene oxide purification step: a step of distilling the mixture containing propylene oxide separated in the above-mentioned (c) separation step to obtain purified propylene oxide;

[0026] (e) cumene conversion step: a step of converting cumyl alcohol in the cumyl alcohol-containing residue obtained in the above separation step (c) into cumene to obtain a cumene-containing solution (1), which is used as a stream (1);

[0027] (f) Cumene purification step: A step of separating the solution (1) of the above-mentioned stream (1) into at least a solution (2) containing purified cumene and a solution (3) containing 2,3-dimethyl-2,3-diphenylbutane, thereby obtaining a stream (2) containing purified cumene and a stream (3) containing 2,3-dimethyl-2,3-diphenylbutane.

[0028] Effects of the Invention

[0029] According to the present invention, a method for producing cumene, an apparatus for producing cumene, and a method for producing propylene oxide can be provided, in which a stream containing 2,3-dimethyl-2,3-diphenylbutane can maintain good fluidity even at room temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1A to Figure 1C This is a diagram for explaining an example of the equipment A included in the cumene production apparatus according to the present embodiment.

[0031] Figure 2A to Figure 2C This is a diagram for explaining an example of the equipment D included in the cumene production apparatus according to the present embodiment. DETAILED DESCRIPTION

[0032] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments.

[0033] <Method for producing cumene>

[0034] The method for producing cumene according to the present embodiment includes the following steps (e) and (f).

[0035] (e) Cumene conversion step: a step of converting cumyl alcohol into cumene to obtain a solution (1) containing cumene, which is used as a stream (1).

[0036] (f) Cumene purification step: A step of separating the solution (1) of the above-mentioned stream (1) into at least a solution (2) containing purified cumene and a solution (3) containing 2,3-dimethyl-2,3-diphenylbutane, thereby obtaining a stream (2) containing purified cumene and a stream (3) containing 2,3-dimethyl-2,3-diphenylbutane.

[0037] As the (e) cumene conversion step, there can be listed: a step of dehydrating cumyl alcohol in the presence of a catalyst and then reacting it with hydrogen to obtain cumene; a step of reacting cumyl alcohol with hydrogen in the presence of a catalyst to perform hydrocracking to obtain cumene, etc. It should be noted that cumyl alcohol refers to 2-phenyl-2-propanol.

[0038] (e) The cumene conversion step is preferably carried out in the presence of carbon monoxide. The carbon monoxide concentration is preferably 0.1% by volume to 10% by volume, more preferably 0.5% by volume to 5% by volume.

[0039] In one embodiment, the isopropylbenzene conversion step includes: a step of dehydrating cumyl alcohol in the presence of a catalyst to obtain a mixture containing α-methylstyrene (hereinafter referred to as the "dehydration step"); and a step of contacting the above-mentioned mixture containing α-methylstyrene obtained in the dehydration step with hydrogen in the presence of a catalyst to react the α-methylstyrene in the above-mentioned mixture with hydrogen to thereby obtain a conversion mixture containing isopropylbenzene (hereinafter referred to as the "hydrogenation step").

[0040] In another embodiment, the cumene conversion step is a step (hereinafter referred to as the "hydrocracking step") in which a residue containing cumyl alcohol is contacted with hydrogen in the presence of a catalyst to react the cumyl alcohol in the residue with the hydrogen to obtain a conversion mixture containing cumene.

[0041] First, an embodiment in which the cumene conversion step includes a dehydration step and a hydrogenation step will be described below.

[0042] The catalyst used in the dehydration step (hereinafter referred to as "dehydration catalyst") includes homogeneous acid catalysts such as sulfuric acid, phosphoric acid, and p-toluenesulfonic acid; and solid acid catalysts such as activated alumina, titanium dioxide, zirconium oxide, silica-alumina, and zeolite. From the viewpoint of improving the reaction efficiency, the dehydration catalyst is preferably a solid acid catalyst, and more preferably activated alumina.

[0043] The dehydration reaction in the dehydration process is usually carried out by contacting cumyl alcohol with a dehydration catalyst. In one embodiment, in order to carry out the hydrogenation reaction in the hydrogenation process after the dehydration reaction, cumyl alcohol can be contacted with a dehydration catalyst in the presence of hydrogen. The dehydration reaction can be implemented in the liquid phase in the presence of a solvent. The solvent must be a solvent that is substantially inert to the reaction raw materials and the product. The solvent may be a substance present in the residue containing cumyl alcohol used. For example, in the case where the residue containing cumyl alcohol contains cumene, the cumene can be used as a solvent, and no other solvents may be used. Typically, the dehydration reaction temperature is preferably 50°C to 450°C, more preferably 150°C to 300°C. Typically, the dehydration reaction pressure is preferably 10kPa-G to 10000kPa-G, more preferably 500kPa-G to 4000kPa-G, and further preferably 1000kPa-G to 2000kPa-G.

[0044] As the catalyst used in the hydrogenation process (hereinafter, recorded as "hydrogenation catalyst"), there can be listed: a catalyst containing a metal of the 10th or 11th group of the periodic table, specifically, there can be listed: a nickel-containing catalyst, a palladium-containing catalyst, a platinum-containing catalyst, and a copper-containing catalyst. From the viewpoint of suppressing the nuclear hydrogenation reaction of the aromatic ring and high yield, the hydrogenation catalyst is preferably a nickel-containing catalyst, a palladium-containing catalyst or a copper-containing catalyst. The nickel-containing catalyst is preferably nickel, nickel-alumina, nickel-silicon dioxide, and nickel-carbon. The palladium-containing catalyst is preferably palladium-alumina, palladium-silicon dioxide, and palladium-carbon. The copper-containing catalyst is preferably copper, Raney copper, copper-chromium, copper-zinc, copper-chromium-zinc, copper-silicon dioxide, and copper-alumina. These catalysts can be used alone or in combination.

[0045] The hydrogenation reaction in the hydrogenation step is carried out by contacting α-methylstyrene and hydrogen with a hydrogenation catalyst. In one embodiment, the hydrogenation reaction is carried out after the dehydration reaction, but in this method, a part of the water generated in the dehydration reaction can be separated by oil-water separation, etc., or it can be contacted with the hydrogenation catalyst together with α-methylstyrene without separating a part of the water generated in the dehydration reaction. The amount of hydrogen required for the hydrogenation reaction only needs to be equimolar to that of α-methylstyrene, but the mixture containing α-methylstyrene obtained in the dehydration step usually also contains components other than α-methylstyrene that consume hydrogen, so an excess of hydrogen is used.

[0046] The higher the partial pressure of hydrogen, the faster the reaction proceeds. Therefore, usually, the molar ratio of hydrogen / α-methylstyrene is preferably 1 / 1 to 20 / 1, more preferably 1 / 1 to 10 / 1, and further preferably 1 / 1 to 3 / 1. In addition, usually, the molar ratio of hydrogen / (isopropylbenzene + cumyl alcohol) is 1 / 25 or more. The molar ratio of hydrogen / (isopropylbenzene + cumyl alcohol) can be greater than 1 / 25. The excess hydrogen remaining after the hydrogenation reaction can also be recycled and used after separation from the reaction liquid (conversion mixture). It should be noted that the amount of "hydrogen" in the above molar ratio is the amount of hydrogen supplied to the hydrogenation reaction, and the amount of "isopropylbenzene + cumyl alcohol" is the total amount of isopropylbenzene and cumyl alcohol in the liquid supplied to the dehydration reaction.

[0047] The method for producing the hydrogen gas used in the hydrogenation step is not particularly limited, and for example, hydrogen gas produced by the following production method can be used. It should be noted that the hydrogen gas used is generally selected in consideration of the price and the load on the environment.

[0048] As methods for producing hydrogen, for example, there can be listed: methods of steam reforming fossil fuels such as natural gas and petroleum, water-gas shift reaction of carbon monoxide, electrolysis of water, electrolysis of salt, dehydrogenation of hydrocarbons, thermal decomposition of methane, by-products from sodium carbonate electrolysis, by-products from steel mills, by-products from coal dry distillation processes, etc. Alternatively, there are known methods of steam reforming the gas generated by decomposing biomass in the same manner as fossil fuels, methods of fermenting methane from biomass and further steam reforming the methane, methods of directly generating hydrogen by fermenting biomass, methods of decomposing water using photocatalysts, etc. In addition, there can be listed: methods of decomposing ammonia.

[0049] The hydrogenation reaction can be carried out in the presence of a solvent in a liquid phase or in a gas phase. The solvent must be a solvent that is substantially inert to the reaction raw materials and products. The solvent may be a substance present in a mixture containing α-methylstyrene. For example, in the case where the mixture containing α-methylstyrene contains cumene, the cumene may be used as a solvent, and no other solvent may be used. Usually, the hydrogenation reaction temperature is preferably 0°C to 500°C, more preferably 30°C to 400°C, and further preferably 50°C to 300°C. Usually, the hydrogenation reaction pressure is preferably 100kPa-G to 10000kPa-G, more preferably 500kPa-G to 4000kPa-G, and further preferably 1000kPa-G to 2000kPa-G.

[0050] The dehydration reaction and the hydrogenation reaction can be advantageously implemented in the form of a slurry or a fixed bed. In the case of large-scale industrial operations, a fixed bed is preferably used. In addition, the dehydration reaction and the hydrogenation reaction can be implemented by reaction modes such as a batch process, a semi-continuous process, and a continuous process. Separate reactors can be used in the dehydration reaction and the hydrogenation reaction, or a single reactor can be used. The reactor of the continuous process includes an adiabatic reactor and an isothermal reactor, but since the isothermal reactor requires equipment for removing heat, an adiabatic reactor is preferably used.

[0051] Next, an embodiment in which the cumene conversion step includes a hydrocracking step will be described below.

[0052] As the catalyst used in the hydrocracking step (hereinafter referred to as "hydrocracking catalyst"), there can be mentioned: a catalyst containing a metal of Group 9, Group 10, Group 11 or Group 12 of the periodic table, specifically, there can be mentioned: a cobalt-containing catalyst, a nickel-containing catalyst, a palladium-containing catalyst, a copper-containing catalyst, and a zinc-containing catalyst. From the viewpoint of suppressing the formation of by-products, the hydrocracking catalyst is preferably a nickel-containing catalyst, a palladium-containing catalyst or a copper-containing catalyst. As nickel-containing catalysts, there can be mentioned: nickel, nickel-alumina, nickel-silicon dioxide, and nickel-carbon. As palladium-containing catalysts, there can be mentioned: palladium-alumina, palladium-silicon dioxide, palladium-carbon, etc. As copper-containing catalysts, there can be mentioned: copper, Raney copper, copper-chromium, copper-zinc, copper-chromium-zinc, copper-silicon dioxide, copper-alumina, etc. The hydrocracking reaction can be carried out in the presence of a solvent in a liquid phase or in a gas phase. The solvent must be a solvent that is substantially inert to the reaction raw materials and products. The solvent may be a substance present in the residue containing cumyl alcohol used. For example, in the case where the residue containing cumyl alcohol contains cumene, the cumene may be used as the solvent, and no other solvent may be used. The amount of hydrogen required for the hydrocracking reaction only needs to be equimolar to that of the cumyl alcohol, but the residue containing cumyl alcohol obtained in the separation step (described later) usually contains components other than cumyl alcohol that consume hydrogen, so an excess amount of hydrogen is used.

[0053] The higher the partial pressure of hydrogen, the faster the reaction proceeds. Therefore, usually, the molar ratio of hydrogen / cumyl alcohol is preferably 1 / 1 to 20 / 1, more preferably 1 / 1 to 10 / 1, and further preferably 1 / 1 to 3 / 1. In addition, usually, the molar ratio of hydrogen / (isopropylbenzene+cumyl alcohol) is more than 1 / 25. The molar ratio of hydrogen / (isopropylbenzene+cumyl alcohol) can be greater than 1 / 25. The excess hydrogen remaining after the hydrocracking reaction can also be recycled and used after being separated from the reaction solution.

[0054] The method for producing hydrogen used in the hydrocracking step is not particularly limited, and for example, hydrogen produced by the following production method can be used. It should be noted that the hydrogen used is generally selected in consideration of price and environmental load.

[0055] As a method for producing hydrogen, for example, there can be listed: a method of steam reforming fossil fuels such as natural gas and petroleum, a water-gas shift reaction of carbon monoxide, electrolysis of water, electrolysis of salt, dehydrogenation of hydrocarbons, thermal decomposition of methane, by-products from sodium carbonate electrolysis, by-products from steel mills, by-products from coal dry distillation processes, etc. Alternatively, there are known methods of steam reforming the gas generated by decomposing biomass in the same manner as fossil fuels, methods of fermenting methane from biomass and further steam reforming the methane, methods of directly generating hydrogen by fermenting biomass, methods of decomposing water using a photocatalyst, etc. In addition, there can be listed: methods such as the decomposition of ammonia.

[0056] Usually, the hydrocracking reaction temperature is preferably 0°C to 500°C, more preferably 50°C to 450°C, and further preferably 150°C to 300°C. Usually, the hydrocracking reaction pressure is preferably 100kPa-G to 10000kPa-G, more preferably 500kPa-G to 4000kPa-G, and further preferably 1000kPa-G to 2000kPa-G. The hydrocracking reaction can be advantageously implemented in the form of a slurry or a fixed bed. In the case of large-scale industrial operations, a fixed bed is preferably used. In addition, the hydrocracking reaction can be implemented by reaction methods such as a batch process, a semi-continuous process, and a continuous process.

[0057] The content of cumene in the conversion mixture containing cumene is usually preferably 90% by mass or more relative to 100% by mass of the conversion mixture containing cumene.

[0058] In the (f) cumene purification step, the stream (3) contains 20% by mass or more and 99% by mass or less of acetophenone and 1% by mass or more and 10% by mass or less of 2,3-dimethyl-2,3-diphenylbutane from the viewpoint of maintaining good fluidity even at room temperature. It should be noted that in this specification, room temperature refers to 15° C. to 25° C.

[0059] From the viewpoint of maintaining good fluidity even at room temperature, the content of acetophenone contained in the stream (3) is preferably 25% by mass or more and 95% by mass or less, and more preferably 30% by mass or more and 90% by mass or less. From the viewpoint of maintaining good fluidity even at room temperature, the content of 2,3-dimethyl-2,3-diphenylbutane contained in the stream (3) is preferably 1.5% by mass or more and 9% by mass or less, and more preferably 2% by mass or more and 8% by mass or less.

[0060] As the acetophenone contained in the stream (3), acetophenone produced in the (a) oxidation step (described later) or the (b) epoxidation step (described later) can be used. In this case, for example, the content of acetophenone contained in the stream (3) can be increased by increasing the reaction temperature in the (a) oxidation step (described later), decreasing the reaction temperature in the (b) epoxidation step (described later), increasing the carbon monoxide concentration in the (e) cumene conversion step, decreasing the temperature of the distillation column in the (f) cumene purification step, and increasing the pressure of the distillation column. In addition, the content of acetophenone contained in the stream (3) can be reduced by decreasing the reaction temperature in the (a) oxidation step (described later), increasing the reaction temperature in the (b) epoxidation step (described later), decreasing the carbon monoxide concentration in the (e) cumene conversion step, and increasing the temperature of the distillation column in the (f) cumene purification step, and decreasing the pressure of the distillation column. In addition, the acetophenone contained in the stream (3) may be acetophenone added to the stream (3).

[0061] The 2,3-dimethyl-2,3-diphenylbutane contained in the feed stream (3) can be produced by controlling the conditions in the (e) cumene conversion step. For example, by lowering the reaction temperature in the (e) cumene conversion step, the content of 2,3-dimethyl-2,3-diphenylbutane contained in the feed stream (3) can be increased. In addition, by increasing the reaction temperature in the (e) cumene conversion step, the content of 2,3-dimethyl-2,3-diphenylbutane contained in the feed stream (3) can be reduced.

[0062] From the viewpoint of improving fluidity, stream (3) may further contain 0.1% by mass to 5% by mass of ethylbenzene. The content of ethylbenzene contained in stream (3) is preferably 0.5% by mass to 4.5% by mass, and more preferably 1.0% by mass to 4.0% by mass.

[0063] When the stream (3) contains ethylbenzene, in one embodiment, the (f) cumene purification step may include: a step of separating the solution (1) of the stream (1) into a solution (2) containing purified cumene, a solution (3) containing 2,3-dimethyl-2,3-diphenylbutane, and a solution (3') containing ethylbenzene; and a step of mixing at least a portion of the solution (3) with at least a portion of the solution (3') to prepare a solution containing 2,3-dimethyl-2,3-diphenylbutane and ethylbenzene to obtain the stream (3). In this embodiment, the solution (2), the solution (3), and the solution (3') may be separated in one step or in two steps. In the two-step separation, for example, the solution (2) and the solution (3) may be separated after the solution (3') is separated, or the solution (2) and the solution (3') may be separated after the solution (3) is separated. In this embodiment, (f) the cumene purification step may include a step of recovering cumene from the solution (3) and / or the solution (3') after the step of separating into the solution (2), the solution (3) and the solution (3').

[0064] From the viewpoint of maintaining better fluidity at room temperature, the stream (3) may further contain waste oil. As the waste oil, for example, waste oil obtained in the (d) propylene oxide purification step (described later) may be used. The stream (3) may further contain cumyl alcohol that has not reacted in the (e) cumene conversion step.

[0065] <Isopropylbenzene production equipment>

[0066] The cumene manufacturing device of the present embodiment is a device for manufacturing cumene using the above-mentioned cumene manufacturing method. The above-mentioned cumene manufacturing device has a device A for separating the solution (1) of the material flow (1) into at least a solution (2) containing purified cumene and a solution (3) containing 2,3-dimethyl-2,3-diphenylbutane. The device A can further separate the solution (1) of the material flow (1) into a solution (3') containing ethylbenzene. It should be noted that the device A can be one distillation tower or multiple distillation towers.

[0067] use Figure 1A to Figure 1C An example of device A is described below. Figure 1A As shown, in one embodiment, the device A is a distillation column, and the solution (2) containing purified cumene, the solution (3) containing 2,3-dimethyl-2,3-diphenylbutane, and the solution (3') containing ethylbenzene are separated in one step. At this time, the lightest solution (3') containing ethylbenzene is separated from the upper part of the device A, and the heaviest solution (3) containing 2,3-dimethyl-2,3-diphenylbutane is separated from the lower part of the device A.

[0068] like Figure 1BAs shown, in another embodiment, the device A comprises two distillation columns, and the solution (2) containing purified cumene, the solution (3) containing 2,3-dimethyl-2,3-diphenylbutane, and the solution (3') containing ethylbenzene are separated in two steps. Specifically, the solution (3') is separated from the top in the first distillation column, and then the solution (2) is separated from the top and the solution (3) is separated from the bottom in the second distillation column.

[0069] like Figure 1C As shown, in another embodiment, the device A comprises two distillation columns, and the solution (2) containing purified cumene, the solution (3) containing 2,3-dimethyl-2,3-diphenylbutane, and the solution (3') containing ethylbenzene are separated in two steps. Specifically, the solution (3) is separated from the bottom in the first distillation column, and then the solution (3') is separated from the top and the solution (2) is separated from the bottom in the second distillation column.

[0070] The cumene production apparatus of this embodiment may further include a device D for recovering cumene from the solution (3) and / or the solution (3'). The device D is connected to the downstream side of the device A. It should be noted that the device D may be one distillation column or a plurality of distillation columns.

[0071] use Figure 2A to Figure 2C An example of device D is described below. Figure 2A As shown, in one embodiment, the device D is a distillation column to recover cumene from the solution (3'). It should be noted that the solution (3') after the cumene is recovered is separated from the upper part of the device D.

[0072] like Figure 2B As shown, in another embodiment, the device D is a distillation tower to recover cumene from the solution (3). It should be noted that the solution (3) after the cumene is recovered is separated from the bottom of the device D.

[0073] like Figure 2C As shown, in another embodiment, the device D is a distillation tower, and cumene is recovered from the solution (3) and the solution (3'). It should be noted that the solution (3) after cumene is recovered is separated from the bottom of the device D, and the solution (3') after cumene is recovered is separated from the top of the device D.

[0074] The cumene production apparatus of the present embodiment may further include a device B for mixing at least a portion of the solution (3) with at least a portion of the solution (3'), and a device C connected to the device B and burning the waste oil. In one embodiment of the cumene production apparatus including the device B and the device C, the device B mixes at least a portion of the solution (3) separated in the device A with at least a portion of the solution (3'). Then, the waste oil is burned in the device C connected to the device B to produce the waste oil'.

[0075] <Method for producing propylene oxide>

[0076] The method for producing propylene oxide according to the present embodiment is a method for producing propylene oxide including the method for producing cumene described above, and includes the following steps (a) to (f).

[0077] (a) Oxidation step: a step of oxidizing cumene to obtain cumene hydroperoxide.

[0078] (b) Epoxidation step: a step of reacting the cumene hydroperoxide obtained in the above-mentioned (a) oxidation step with propylene to obtain a reaction mixture containing propylene oxide and cumyl alcohol.

[0079] (c) Separation step: a step of separating a mixture containing propylene oxide from the reaction mixture containing propylene oxide and cumyl alcohol obtained in the above-mentioned (b) epoxidation step to obtain a residue containing cumyl alcohol.

[0080] (d) Propylene oxide purification step: a step of distilling the mixture containing propylene oxide separated in the above-mentioned (c) separation step to obtain purified propylene oxide.

[0081] (e) Cumene conversion step: a step of converting the cumyl alcohol in the cumyl alcohol-containing residue obtained in the above-mentioned separation step (c) into cumene to obtain a cumene-containing stream (1).

[0082] (f) Cumene purification step: a step of separating the above stream (1) into at least a stream (2) containing purified cumene and a stream (3) containing 2,3-dimethyl-2,3-diphenylbutane.

[0083] In the oxidation step (a), cumene is oxidized to obtain cumene hydroperoxide. The oxidation of cumene is usually carried out by auto-oxidation using an oxygen-containing gas such as air or oxygen-enriched air. The oxidation reaction can be carried out without using an additive or using an additive such as an alkali. The reaction temperature is usually 50°C to 200°C, and the reaction pressure is usually between atmospheric pressure and 5 MPa.

[0084] Examples of the additive include alkali metal hydroxides such as NaOH and KOH; alkaline earth metal hydroxides; alkali metal carbonates such as Na2CO3 and NaHCO3; ammonia; (NH4)2CO3; alkali metal ammonium carbonates, and the like.

[0085] In the (b) epoxidation step, the cumene hydroperoxide obtained in the (a) oxidation step is reacted with propylene to obtain a reaction mixture containing propylene oxide and cumyl alcohol. From the viewpoint of generating propylene oxide in high yield and high selectivity, the (b) epoxidation step is preferably implemented in the presence of a catalyst containing titanium-containing silicon oxide. These catalysts are preferably so-called Ti-silica catalysts containing Ti chemically bonded to silicon oxide. As Ti-silica catalysts, for example, catalysts in which a Ti compound is supported on a silica carrier, catalysts obtained by combining with silicon oxide by a coprecipitation method or a sol-gel method, or Ti-containing zeolite compounds, etc.

[0086] (b) The epoxidation reaction in the epoxidation step is carried out by contacting propylene and cumene hydroperoxide with a catalyst. The molar ratio of propylene to cumene hydroperoxide (propylene / cumene hydroperoxide) is preferably 2 / 1 to 50 / 1. When the molar ratio is 2 / 1 or more, epoxidation can be carried out at a good reaction rate, so the epoxidation reaction can be carried out efficiently. In addition, when the molar ratio is 50 / 1 or less, the supply amount of propylene can be suppressed from becoming excessive, so the energy required in the step of recovering and recycling propylene can be suppressed.

[0087] The method for producing propylene used in the epoxidation step is not particularly limited, and propylene produced by the following production method can be used.

[0088] Examples of methods for producing propylene include cracking of naphtha or ethane, fluidized catalytic cracking of vacuum gas oil, dehydrogenation of propane, disproportionation of ethylene and 2-butene, MTO (Methanol to Olefin) reaction for converting methanol or dimethyl ether, Fischer-Tropsch (FT) synthesis for reacting carbon monoxide with hydrogen, dehydration of isopropanol, etc. In addition, propylene produced by the following methods can be used: a method for obtaining propylene from bioethanol and / or isopropanol produced from plants as raw materials, a FT synthesis method using carbon dioxide and biomass, and a method for catalytic cracking of waste plastics, etc., which are methods for reducing the load on the environment.

[0089] The epoxidation reaction can be carried out in a liquid phase using a solvent. The solvent should be liquid at the temperature and pressure during the reaction and be substantially inert to the reactants and products. As the solvent, for example, cumene can be used. In addition, as solvents other than cumene, for example, monocyclic aromatic solvents (specifically, benzene, toluene, chlorobenzene, o-dichlorobenzene, etc.), alkanes (specifically, octane, decane, dodecane, etc.), etc. can be cited.

[0090] The epoxidation reaction temperature is usually 0° C. to 200° C., preferably 25° C. to 200° C. The pressure may be a pressure sufficient to keep the reaction mixture in a liquid state, and is usually advantageously 100 kPa to 10000 kPa.

[0091] The epoxidation reaction can be advantageously carried out using a catalyst in the form of a slurry or a fixed bed. In the case of large-scale industrial operations, a fixed bed is preferably used. In addition, it can be carried out by a batch process, a semi-continuous process or a continuous process.

[0092] The content of propylene oxide in the reaction mixture obtained in the (b) epoxidation step is preferably 1% to 31% by mass, more preferably 1% to 23% by mass. In addition, the content of cumyl alcohol in the reaction mixture is preferably 5% to 80% by mass, more preferably 5% to 60% by mass, and further preferably 5% to 40% by mass.

[0093] The cumyl alcohol produced in the (b) epoxidation step is supplied to the (e) cumene conversion step in the above-mentioned method for producing cumene. Usually, the cumyl alcohol-containing liquid obtained by recovering propylene oxide and unreacted propylene from the reaction mixture obtained in the epoxidation reaction is supplied to the (e) cumene conversion step.

[0094] In the separation step (c), a mixture containing propylene oxide is separated from the reaction mixture containing propylene oxide and cumyl alcohol obtained in the epoxidation step (b), and a residue containing cumyl alcohol is obtained. As a separation method, a method using a distillation tower (preferably a plurality of distillation towers) can be cited. The pressure in the distillation tower is preferably 100 kPa to 5000 kPa, and more preferably 100 kPa to 3000 kPa. In addition, the tower top temperature is preferably -50°C to 150°C, and more preferably 0°C to 130°C. At this time, the tower bottom temperature is preferably 50°C to 230°C, and more preferably 60°C to 210°C.

[0095] The content of propylene oxide in the separated mixture is preferably 99% by mass or more relative to 100% by mass of the separated mixture containing propylene oxide. The content of cumyl alcohol in the residue is preferably 5% to 80% by mass, more preferably 5% to 60% by mass, and further preferably 5% to 40% by mass relative to 100% by mass of the residue containing cumyl alcohol. The residue containing cumyl alcohol contains cumene, acetophenone, ethylbenzene, phenol, cymene, etc. as components other than cumyl alcohol.

[0096] In the (d) propylene oxide purification step, the mixture containing propylene oxide separated in the (c) separation step is distilled to obtain purified propylene oxide. The mixture containing propylene oxide obtained in the (c) separation step usually contains water, hydrocarbons, and oxygen-containing compounds as impurities. Examples of hydrocarbons include hydrocarbons having 3 to 7 carbon atoms. Examples of oxygen-containing compounds include methanol, acetaldehyde, acetone, propionaldehyde, methyl formate, and the like.

[0097] As a method for removing these impurities, known distillation techniques may be appropriately combined. However, from the viewpoint of effectively removing water, hydrocarbons and oxygen-containing compounds, it is preferred to purify by combining extractive distillation using hydrocarbons having 7 to 10 carbon atoms as an extractant with other distillations.

[0098] Examples of hydrocarbons having 7 to 10 carbon atoms as extractants include straight-chain saturated hydrocarbons such as n-heptane, n-octane, n-nonane, and n-decane; and branched-chain saturated hydrocarbons such as 2,2-dimethylpentane, 2,3-dimethylpentane, 2,2-dimethylhexane, and 2,3-dimethylhexane. It should be noted that these extractants may be used alone or as a mixture of these compounds.

[0099] The types and operating conditions of the extractive distillation column and other distillation columns, the amount of the extractant used, etc. can be appropriately determined according to the quality of the required product.

[0100] The (e) cumene conversion step and the (f) cumene purification step are the same as those in the method for producing cumene of the present embodiment. It should be noted that the cumyl alcohol in the (e) cumene conversion step is the cumyl alcohol in the cumyl alcohol-containing residue obtained in the (c) separation step.

[0101] The cumene obtained in the (f) cumene purification step is recycled to the (a) oxidation step. Alternatively, the obtained cumene may be purified by distillation, water washing, etc. and then recycled to the (a) oxidation step.

[0102] It should be noted that the method for producing cumene, the apparatus for producing cumene, and the method for producing propylene oxide according to the present embodiment are not limited to the above-described embodiment, and various modifications may be made without departing from the spirit of the present invention.

[0103] The present invention includes the following aspects.

[0104] [1] A method for producing cumene, wherein the method comprises the following steps (e) and (f):

[0105] (e) Cumene conversion step: a step of converting cumyl alcohol into cumene to obtain a solution (1) containing cumene, which is used as a feed stream (1);

[0106] (f) a cumene purification step: a step of separating the solution (1) of the stream (1) into at least a solution (2) containing purified cumene and a solution (3) containing 2,3-dimethyl-2,3-diphenylbutane, thereby obtaining a stream (2) containing purified cumene and a stream (3) containing 2,3-dimethyl-2,3-diphenylbutane,

[0107] The stream (3) contains 20% by mass or more and 99% by mass or less of acetophenone and 1% by mass or more and 10% by mass or less of 2,3-dimethyl-2,3-diphenylbutane.

[0108] [2] The method for producing cumene according to [1] above, wherein the stream (3) further contains 0.1 mass % to 5 mass % of ethylbenzene.

[0109] [3] The method for producing cumene according to [2] above, wherein:

[0110] The (f) cumene purification step comprises:

[0111] A step of separating the solution (1) of the stream (1) into a solution (2) containing purified cumene, a solution (3) containing 2,3-dimethyl-2,3-diphenylbutane, and a solution (3') containing ethylbenzene; and

[0112] A step of mixing at least a portion of the solution (3) with at least a portion of the solution (3') to prepare a solution containing 2,3-dimethyl-2,3-diphenylbutane and ethylbenzene to obtain the stream (3).

[0113] [4] A cumene production apparatus, wherein the cumene production apparatus is an apparatus for producing cumene using the cumene production method described in any one of [1] to [3] above, wherein:

[0114] The cumene production apparatus includes a device A for separating the solution (1) of the stream (1) into at least a solution (2) containing purified cumene and a solution (3) containing 2,3-dimethyl-2,3-diphenylbutane.

[0115] [5] The cumene production apparatus according to [4] above, wherein the device A further separates the solution (1) of the stream (1) into a solution (3') containing ethylbenzene.

[0116] [6] The apparatus for producing cumene as described in [4] or [5] above, wherein the device A is a distillation tower.

[0117] [7] The apparatus for producing cumene according to [4] or [5] above, wherein the device A is a plurality of distillation columns.

[0118] [8] The cumene production apparatus according to any one of [5] to [7], further comprising a device D for recovering cumene from the solution (3) and / or the solution (3').

[0119] [9] The apparatus for producing cumene as described in [8] above, wherein the device D is a distillation tower.

[0120]

[10] The apparatus for producing cumene as described in [8] above, wherein the device D is a plurality of distillation columns.

[0121]

[11] A method for producing propylene oxide, comprising the method for producing cumene according to any one of [1] to [3] above, wherein:

[0122] The method for producing propylene oxide comprises the following steps (a) to (f),

[0123] (a) Oxidation step: a step of oxidizing cumene to obtain cumene hydroperoxide;

[0124] (b) epoxidation step: a step of reacting the cumene hydroperoxide obtained in the oxidation step (a) with propylene to obtain a reaction mixture containing propylene oxide and cumyl alcohol;

[0125] (c) a separation step: a step of separating a mixture containing propylene oxide from the reaction mixture containing propylene oxide and cumyl alcohol obtained in the epoxidation step (b) to obtain a residue containing cumyl alcohol;

[0126] (d) propylene oxide purification step: a step of distilling the mixture containing propylene oxide separated in the separation step (c) to obtain purified propylene oxide;

[0127] (e) cumene conversion step: a step of converting cumyl alcohol in the cumyl alcohol-containing residue obtained in the separation step (c) into cumene to obtain a cumene-containing solution (1), which is used as a stream (1);

[0128] (f) Cumene purification step: a step of separating the solution (1) of the stream (1) into at least a solution (2) containing purified cumene and a solution (3) containing 2,3-dimethyl-2,3-diphenylbutane, thereby obtaining a stream (2) containing purified cumene and a stream (3) containing 2,3-dimethyl-2,3-diphenylbutane.

[0129] Example

[0130] Hereinafter, the present invention will be described in more detail using Examples and Comparative Examples, but the present invention is not limited to the following Examples.

[0131] (Example 1)

[0132] 2,3-Dimethyl-2,3-diphenylbutane, cumyl alcohol and acetophenone were mixed in the ratio shown in Table 1 and the temperature was kept at 50° C., and a solution having good fluidity was obtained. In addition, the solution was cooled to 21.4° C., and the good fluidity was maintained.

[0133] (Example 2)

[0134] 2,3-Dimethyl-2,3-diphenylbutane and acetophenone were mixed in the ratio shown in Table 1 and the temperature was kept at 50° C., whereby a solution having good fluidity was obtained. Furthermore, the solution was cooled to 21.4° C., whereby good fluidity was maintained.

[0135] (Example 3)

[0136] 2,3-Dimethyl-2,3-diphenylbutane and acetophenone were mixed in the ratio shown in Table 1 and the temperature was kept at 50° C., whereby a solution having good fluidity was obtained. Furthermore, the solution was cooled to 21.4° C., whereby good fluidity was maintained.

[0137] (Comparative Example 1)

[0138] 2,3-Dimethyl-2,3-diphenylbutane, cumyl alcohol, acetophenone and naphtha cracked heavy oil were mixed in the ratio shown in Table 1 and the temperature was kept at 50°C. As a result, a solution with good fluidity was obtained. However, when the solution was cooled to 21.4°C, the solution solidified and lost fluidity.

[0139] (Comparative Example 2)

[0140] 2,3-Dimethyl-2,3-diphenylbutane, cumyl alcohol and acetophenone were mixed in the ratio shown in Table 1 and the temperature was kept at 50° C., and a solution with good fluidity was obtained. However, when the solution was cooled to 21.4° C., the solution solidified and lost fluidity.

[0141] (Comparative Example 3)

[0142] 2,3-Dimethyl-2,3-diphenylbutane, cumyl alcohol and acetophenone were mixed in the ratio shown in Table 1 and the temperature was kept at 50° C., and a solution with good fluidity was obtained. However, when the solution was cooled to 21.4° C., the solution solidified and lost fluidity.

[0143] (Comparative Example 4)

[0144] 2,3-Dimethyl-2,3-diphenylbutane, cumyl alcohol and acetophenone were mixed in the ratio shown in Table 1 and the temperature was kept at 50° C., and a solution with good fluidity was obtained. However, when the solution was cooled to 21.4° C., the solution solidified and lost fluidity.

[0145] (Comparative Example 5)

[0146] 2,3-Dimethyl-2,3-diphenylbutane, cumyl alcohol and acetophenone were mixed in the ratio shown in Table 1 and the temperature was kept at 50° C., and a solution with good fluidity was obtained. However, when the solution was cooled to 21.4° C., the solution solidified and lost fluidity.

[0147] [Table 1]

[0148]

[0149] From the above results, it can be said that in the method for producing cumene that satisfies all the constituent requirements of the present invention, a stream containing 2,3-dimethyl-2,3-diphenylbutane can maintain good fluidity even at room temperature.

Claims

1. A method for producing cumene, wherein: The method for producing cumene comprises the following steps (e) and (f), (e) Cumene conversion step: a step of converting cumyl alcohol into cumene to obtain a solution (1) containing cumene, which is used as a feed stream (1); (f) a cumene purification step: a step of separating the solution (1) of the stream (1) into at least a solution (2) containing purified cumene and a solution (3) containing 2,3-dimethyl-2,3-diphenylbutane, thereby obtaining a stream (2) containing purified cumene and a stream (3) containing 2,3-dimethyl-2,3-diphenylbutane, The stream (3) contains 20% by mass or more and 99% by mass or less of acetophenone and 1% by mass or more and 10% by mass or less of 2,3-dimethyl-2,3-diphenylbutane.

2. The method for producing cumene according to claim 1, wherein: The stream (3) further contains 0.1% by mass or more and 5% by mass or less of ethylbenzene.

3. The method for producing cumene according to claim 2, wherein: The (f) cumene purification step comprises: A step of separating the solution (1) of the stream (1) into a solution (2) containing purified cumene, a solution (3) containing 2,3-dimethyl-2,3-diphenylbutane, and a solution (3') containing ethylbenzene; and A step of mixing at least a portion of the solution (3) with at least a portion of the solution (3') to prepare a solution containing 2,3-dimethyl-2,3-diphenylbutane and ethylbenzene to obtain the stream (3).

4. A device for producing cumene, wherein the device for producing cumene is a device for producing cumene using the method for producing cumene according to claim 1, wherein: The cumene production apparatus includes a device A for separating the solution (1) of the stream (1) into at least a solution (2) containing purified cumene and a solution (3) containing 2,3-dimethyl-2,3-diphenylbutane.

5. The production apparatus for cumene according to claim 4, wherein: The apparatus A further separates the solution (1) of the stream (1) into a solution (3') containing ethylbenzene.

6. The production apparatus for cumene according to claim 4 or 5, wherein: The device A is a distillation column.

7. The production apparatus for cumene according to claim 4 or 5, wherein: The equipment A is a plurality of distillation columns.

8. The production apparatus for cumene according to claim 5, wherein: The cumene production apparatus further comprises a device D for recovering cumene from the solution (3) and / or the solution (3').

9. The production apparatus for cumene according to claim 8, wherein: The device D is a distillation column.

10. The production apparatus for cumene according to claim 8, wherein: The equipment D is a plurality of distillation columns.

11. A method for producing propylene oxide, comprising the method for producing cumene according to claim 1, wherein: The method for producing propylene oxide comprises the following steps (a) to (f), (a) Oxidation step: a step of oxidizing cumene to obtain cumene hydroperoxide; (b) epoxidation step: a step of reacting the cumene hydroperoxide obtained in the oxidation step (a) with propylene to obtain a reaction mixture containing propylene oxide and cumyl alcohol; (c) a separation step: a step of separating a mixture containing propylene oxide from the reaction mixture containing propylene oxide and cumyl alcohol obtained in the epoxidation step (b) to obtain a residue containing cumyl alcohol; (d) propylene oxide purification step: a step of distilling the mixture containing propylene oxide separated in the separation step (c) to obtain purified propylene oxide; (e) cumene conversion step: a step of converting cumyl alcohol in the cumyl alcohol-containing residue obtained in the separation step (c) into cumene to obtain a cumene-containing solution (1), which is used as a stream (1); (f) Cumene purification step: a step of separating the solution (1) of the stream (1) into at least a solution (2) containing purified cumene and a solution (3) containing 2,3-dimethyl-2,3-diphenylbutane, thereby obtaining a stream (2) containing purified cumene and a stream (3) containing 2,3-dimethyl-2,3-diphenylbutane.

Images