Method for producing tertiary butyl alcohol

Abstract

The present invention provides a method for producing a tertiary butyl alcohol, the method comprising (i) a step in which a starting material liquid that contains isobutylene and water is supplied into a reactor that comprises a cation exchange resin, and (ii) a step in which a reaction product that contains a tertiary butyl alcohol is produced by a hydration reaction of isobutylene in the reactor. In the step (ii), the average linear velocity of the starting material liquid based on empty tower as calculated by formula (I) is 5 m / hr or more; and the volume (Vw) of the water phase in a fluid (fluid A) in the reactor relative to the total volume of the fluid A is 4% by volume to 12% by volume. Formula (I): (Average linear velocity (m / hr) of starting material liquid) = (Volume flow rate (m3 / hr) of starting material liquid) / (Cross-sectional area (m2) of reactor)

Description

Method for producing tertiary butyl alcohol

[0001] The present invention relates to a method for producing tertiary butyl alcohol (hereinafter also referred to as TBA).

[0002] Tertiary butyl alcohol is used as a raw material for the production of methyl methacrylate by a gas-phase catalytic oxidation process. A known method for producing tertiary butyl alcohol is a hydration reaction of isobutylene (2-methylpropene) with water using a catalyst. In this reaction, since the raw materials isobutylene and water have low mutual solubility, the reaction generally occurs in a heterogeneous liquid phase in which the isobutylene and water are phase-separated. Patent Documents 1 and 2, for example, describe methods for producing tertiary butyl alcohol in a heterogeneous liquid phase, in which isobutylene and water are brought into contact with each other by a predetermined method on the surface of strong acid cation exchange resin catalyst particles.

[0003] However, the heterogeneous liquid phase methods described in Patent Documents 1 and 2 have a low reaction rate, and a large reactor is required to ensure a sufficient production volume, which increases the equipment cost. Therefore, industrially, a method that can achieve a higher reaction rate is desired.

[0004] On the other hand, Patent Document 3 describes a method of carrying out a reaction in a homogeneous liquid phase using an aqueous solution of an aliphatic carboxylic acid having 1 to 6 carbon atoms. However, this method requires a step of separating a carboxylic acid ester of tertiary butyl alcohol from the reaction solution in order to obtain tertiary butyl alcohol, which increases equipment costs.

[0005] Patent Document 4 also describes a method in which the reaction is carried out in a homogeneous liquid phase and includes a step of separating tertiary butyl alcohol during the reaction. However, in this method, an aqueous tertiary butyl alcohol solution is added to the reactor to form a homogeneous liquid phase, and therefore the conversion rate is limited by equilibrium.

[0006] JP-A-54-030104 JP-A-54-30105 JP-A-60-051451 JP-A-60-233024

[0007] The present invention has been made to solve the above problems, and its object is to provide a method for producing tertiary butyl alcohol with a high isobutylene conversion rate while reducing equipment costs and production costs.

[0008] The present inventors have conducted extensive research to solve the above-mentioned problems. As a result, they have surprisingly found that even in a reaction in a heterogeneous liquid phase separated into an isobutylene phase and an aqueous phase, a sufficient reaction rate can be obtained by setting the linear velocity of the raw material liquid and the volume of the aqueous phase in the fluid during the hydration reaction within specific ranges, and have thus completed the present invention. That is, the present invention includes the following: [1]: A method for producing tertiary butyl alcohol, comprising: (i) a step of supplying a raw material liquid containing isobutylene and water to a reactor having a cation exchange resin; and (ii) a step of producing a reaction product containing tertiary butyl alcohol in the reactor by a hydration reaction of isobutylene, wherein in the step (ii), the average linear velocity of the raw material liquid on an empty column basis calculated by the following formula (I) is 5 m / hr or more, and ３ / hr) / cross-sectional area of ​​reactor (m ２(I) A method for producing tertiary butyl alcohol, wherein the volume (Vw) of the aqueous phase in the fluid (fluid A) relative to the total volume of the fluid in the reactor is 4 to 12% by volume. [2]: A method for producing tertiary butyl alcohol according to [1], wherein in the step (ii), the average linear velocity of the raw material liquid is 5 to 29 m / hr on an empty column basis. [3]: A method for producing tertiary butyl alcohol according to [1] or [2], wherein in the step (ii), the average linear velocity of the raw material liquid is 7 to 13 m / hr on an empty column basis. [4]: ​​A method for producing tertiary butyl alcohol according to any of [1] to [3], wherein in the step (ii), the Vw is 5 to 10% by volume. [5]: A method for producing tertiary butyl alcohol according to any of [1] to [4], wherein in the step (ii), the outlet temperature of the reactor is 75°C or lower. [6]: The method for producing tertiary butyl alcohol according to any one of [1] to [5], further comprising (iii) a step of producing tertiary butyl alcohol by separating unreacted isobutylene from the reaction product containing tertiary butyl alcohol produced in the step (ii). [7]: The method for producing tertiary butyl alcohol according to [6], wherein, when the amount of tertiary butyl alcohol supplied to the reactor per unit time in the step (i) is Mi (mol / hr), and the amount of tertiary butyl alcohol produced per unit time in the step (iii) is Miii (mol / hr), Mi / Miii is 1 to 7. [8]: The method for producing tertiary butyl alcohol according to [7], wherein Mi / Miii is 1 to 5.

[0009] According to the present invention, a method for producing tertiary butyl alcohol with a high isobutylene conversion rate can be provided, while reducing equipment costs and production costs.

[0010] 1 is an example of a reaction apparatus for carrying out the present invention. This is a three-phase diagram showing the proportions of each component when the total of hydrocarbons, water, and TBA in fluid A is taken as 100 mol %. The shaded area indicates a region in fluid A where the volume (Vw) of the aqueous phase in fluid A relative to the total volume of fluid A is 4 to 12 vol %. This is a three-phase diagram showing the proportions of each component when the total of hydrocarbons, water, and TBA in fluid A is taken as 100 mol %. The shaded area indicates a region in fluid A where the volume (Vw) of the aqueous phase in fluid A relative to the total volume of fluid A is 5 to 10 vol %.

[0011] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following. In this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​written before and after "to" as the lower and upper limits, and "A to B" means A or more and B or less.

[0012] The method for producing tertiary butyl alcohol according to this embodiment includes the following steps (i) and (ii): (i) a step of supplying a raw material liquid containing isobutylene and water to a reactor having a cation exchange resin; and (ii) a step of producing a reaction product containing tertiary butyl alcohol in the reactor by a hydration reaction of isobutylene. In addition, in the step (ii) of the method for producing tertiary butyl alcohol according to this embodiment, the average linear velocity of the raw material liquid calculated by the following formula (I) is 5 m / hr or more on an empty column basis. Average linear velocity of raw material liquid (m / hr) = Volumetric flow rate of raw material liquid (m ３ / hr) / cross-sectional area of ​​reactor (m ２) (I) The volume (Vw) of the aqueous phase in the fluid A relative to the total volume of the fluid (fluid A) in the reactor is 4 to 12 volume %. By using such a method, it is possible to reduce equipment costs and production costs and produce tertiary butyl alcohol with a high isobutylene conversion. Furthermore, the method for producing tertiary butyl alcohol according to this embodiment preferably further comprises the following step (iii): (iii) a step of producing tertiary butyl alcohol by separating unreacted isobutylene from the reaction product containing tertiary butyl alcohol produced in the step (ii). Each step will be described in detail below.

[0013] [Step (i)] In step (i), a raw material liquid containing isobutylene and water is supplied to a reactor having a cation exchange resin.

[0014] <Reactor> The reactor used in this embodiment may be any type, such as a stirred tank reactor, a fixed bed reactor, or a column reactor. The reaction may be performed in a batch, semi-batch, or continuous flow mode. The reactors may be arranged in series or parallel. As shown in FIG. 1, it is preferable that multiple reactors are arranged in series, and it is more preferable that two to five reactors are arranged in series. When multiple reactors are used, the effects of the present invention can be achieved as long as the average linear velocity and Vw of the raw material liquid satisfy the specified conditions in at least one reactor. From the viewpoint of isobutylene conversion, it is preferable that the reactor to which the raw material liquid is first supplied, i.e., the first reactor 5 shown in FIG. 1, satisfy the above conditions. Hereinafter, when multiple reactors are used, the term "reactor" in this specification refers to the reactor to which the raw material liquid is first supplied, unless otherwise specified. The cation exchange resin is preferably a strongly acidic cation exchange resin. Examples include Lewatit (trade name) manufactured by Bayer and Amberlyst (trade name) manufactured by DuPont. The position of the cation exchange resin in the reactor, the proportion of the cation exchange resin in the reactor, etc. are not particularly limited, and any commonly used form can be applied.

[0015] In the reaction apparatus of Figure 1, raw materials isobutylene and water are supplied from an isobutylene supply port 1 and a water supply port 2, respectively, and the raw material is transferred to a first reactor 5 by a pump 3. When transferred to the first reactor 5, the raw material is cooled to a predetermined temperature by a raw material cooler 4. The reaction product of the first reactor 5 is transferred to a second reactor 7, and a portion of it is fed again as a raw material. When transferred to the second reactor 7, the reaction product of the first reactor 5 is cooled to a predetermined temperature by a raw material cooler 6. The reaction product of the second reactor 7 is cooled by a raw material cooler 8 and transferred to a third reactor 9. The reaction product of the third reactor 9 is transferred to a TBA separation column 10. In the TBA separation column 10, unreacted isobutylene in the reaction product of the third reactor 9 is cooled by a condenser 11 and discharged from an unreacted isobutylene discharge port 13. Furthermore, TBA in the reaction product of the third reactor 9 is heated by a reboiler 12 and discharged from a TBA discharge port 14, and a part of it is supplied again to the first reactor 5 through a TBA circulation line 15 as a raw material.

[0016] <Raw Material Liquid> In this embodiment, the raw material liquid contains isobutylene and water. The isobutylene concentration in the raw material liquid is preferably 4 to 35 mol%. When the isobutylene concentration is 4 mol% or more, the reaction rate of the hydration reaction is improved in step (ii) described below. Furthermore, when the isobutylene concentration is 35 mol% or less, isobutylene can be obtained inexpensively, thereby reducing production costs. It is more preferable that the lower limit of the isobutylene concentration is 8 mol% or more and the upper limit is 18 mol% or less.

[0017] The water is not particularly limited, but deionized water, distilled water, etc. are preferred, and deionized water is more preferred. Impurities in the water may deactivate the catalyst or have a negative effect on product quality, so it is preferable to remove them as much as possible.

[0018] The raw material liquid may contain tertiary butyl alcohol. In this case, when the amount of tertiary butyl alcohol supplied to the reactor per unit time in step (i) is Mi (mol / hr), and the amount of tertiary butyl alcohol produced per unit time in step (iii) described below is Miii (mol / hr), it is preferable that Mi / Miii be 1 to 7. This improves the isobutylene conversion rate in step (ii) described below, thereby reducing production costs in step (iii) described below. The upper limit of Mi / Miii is more preferably 5 or less, even more preferably 4.5 or less, and particularly preferably 4 or less. The tertiary butyl alcohol contained in the raw material liquid may contain recycled TBA using the tertiary butyl alcohol produced in step (iii) described below. Mi / Miii can be adjusted, for example, by changing the feed rate of the raw material liquid supplied to the reactor or the tertiary butyl alcohol concentration of the raw material liquid.

[0019] The raw material liquid may also contain hydrocarbons other than those mentioned above. The hydrocarbon is preferably at least one selected from hydrocarbons having four carbon atoms, such as butenes other than isobutylene (1-butene and / or 2-butene) and butanes (n-butane, isobutane, etc.). Such isobutylene-containing hydrocarbons can be obtained as by-products obtained when ethylene is obtained by thermal cracking of naphtha in the presence of steam, by-products obtained by catalytic cracking of heavy oil, or by removing butadiene from these by-products.

[0020] In step (ii) described below, the raw material liquid is supplied so that the average linear velocity calculated by the formula (I) based on the superficial column is 5 m / hr or more. As a result, when Vw is within the specified range in step (ii), the reaction rate of the hydration reaction is improved. The reason for this is thought to be as follows: When Vw is within the specified range in step (ii) described below, a portion of the aqueous phase disperses in the isobutylene phase to form droplets. At this time, if the raw material liquid is supplied at a specified speed, the droplet diameter decreases and the number of droplets increases. This increases the contact interface area between the isobutylene phase and the aqueous phase in fluid A, promoting interphase mass transfer. The lower limit of the average linear velocity of the raw material liquid is preferably 7 m / hr or more, more preferably 8 m / hr or more. The upper limit is preferably 29 m / hr, more preferably 15 m / hr, even more preferably 14 m / hr, particularly preferably 13 m / hr, and most preferably 12 m / hr.

[0021] [Step (ii)] In the step (ii), a reaction product containing tertiary butyl alcohol is produced in the reactor by a hydration reaction of isobutylene.

[0022] <Fluid in reactor during hydration reaction> In step (ii), the average linear velocity of the raw material liquid calculated by the following formula (I) is 5 m / hr or more on an empty column basis. Average linear velocity of raw material liquid (m / hr) = Volumetric flow rate of raw material liquid (m ３ / hr) / cross-sectional area of ​​reactor (m ２ ) (I) Here, the volumetric flow rate of the raw material liquid is the volumetric flow rate of the raw material liquid supplied to the reactor in the step (i). The cross-sectional area of ​​the reactor is the cross-sectional area using the inserted portion of the reactor. If the cross-sectional area of ​​the reactor is not uniform, the cross-sectional area is the cross-sectional area of ​​the portion with the largest cross-sectional area in the reactor. The average linear velocity of the raw material liquid on an empty column basis can be adjusted, for example, by changing the volumetric flow rate of the raw material liquid supplied to the reactor in the step (i).

[0023] In step (ii), the volume (Vw) of the aqueous phase in fluid A relative to the total volume of the fluid (fluid A) in the reactor is 4 to 12 vol. Here, the aqueous phase refers to a phase containing 90 mol. Furthermore, the presence of an aqueous phase in fluid A means that the reaction occurs in a heterogeneous liquid phase separated into an aqueous phase and an isobutylene phase in the reactor. Having Vw within the specified range improves the reaction rate of the isobutylene hydration reaction. This is thought to be because a portion of the aqueous phase is dispersed in the isobutylene phase and exists as water droplets, promoting interphase mass transfer with the isobutylene phase. The lower limit of Vw is preferably 4 vol. % or more, more preferably 5 vol. % or more. The upper limit is preferably 10 vol. % or less, more preferably 9 vol. % or less. Vw can be adjusted, for example, by the concentration of tertiary butyl alcohol contained in the raw material liquid. Vw can be adjusted to 4 to 12 vol. % by supplying a raw material liquid containing tertiary butyl alcohol so that the composition of fluid A falls within the range indicated by the shaded area in FIG. 2 . Similarly, by supplying a raw material liquid containing tertiary butyl alcohol so that the composition of fluid A falls within the range shown by the shaded area in FIG. 3, Vw can be set to 5 to 10% by volume.

[0024] It can be confirmed using FIG. 2 that Vw is 4 to 12 volume %. If the composition of fluid A is within the range shown by the shaded area in FIG. 2 based on the composition of hydrocarbons, water, and TBA in the raw material liquid containing tertiary butyl alcohol, it can be determined that Vw is 4 to 12 volume %. Similarly, if the composition of fluid A is within the range shown by the shaded area in FIG. 3, it can be determined that Vw is 5 to 10 volume %. Vw can also be determined by the following method. Using a process simulator, the density D (mol / m) of fluid A can be calculated from the composition, temperature, and pressure of fluid A. ３ ), the density Dw (mol / m ３ ) and the density Do (mol / m ３) is calculated. As a process simulator, for example, Aspen Plus manufactured by Aspen Technology can be used. Next, by using the obtained values ​​of D, Dw, and Do and solving the simultaneous equations consisting of the following formulas (II) and (III), it is possible to calculate the volume Vw (vol %) of the water phase in fluid A relative to the total volume of fluid A, and the volume Vi (vol %) of the isobutylene phase in fluid A relative to the total volume of fluid A. D=Dw×Vw / 100+Do×Vo / 100 (II) Vw+Vi=100 (III)

[0025] <Other Hydration Reaction Conditions> The reactor outlet temperature during the hydration reaction is preferably 75°C or lower. This can suppress the amount of by-products produced in the hydration reaction. This is thought to be because, by setting the reaction temperature at 75°C or lower, the relative reaction rate of side reactions such as the dimerization reaction of isobutylene relative to the hydration reaction rate of isobutylene can be kept low. The reactor outlet temperature preferably has a lower limit of 40°C or higher and an upper limit of 65°C or lower. The pressure inside the reactor during the hydration reaction is preferably 0.2 to 2.0 MPa (G). However, (G) indicates gauge pressure. This allows the raw material isobutylene to be sufficiently liquefied. The reactor pressure preferably has a lower limit of 0.4 MPa (G) and an upper limit of 1.6 MPa (G). To maintain the pressure inside the reactor during the hydration reaction, an inert gas that does not participate in the hydration reaction may be introduced into the reactor. Examples of inert gases include nitrogen and argon.

[0026] [Step (iii)] In step (iii), unreacted isobutylene is separated from the reaction product containing tertiary butyl alcohol produced in step (ii) to produce tertiary butyl alcohol. A high conversion rate of isobutylene in step (ii) reduces the production cost in step (iii). Separation equipment such as a distillation apparatus, an extraction apparatus, or a membrane separation apparatus can be used to separate the unreacted isobutylene, with a distillation apparatus being preferred. As the distillation apparatus, a distillation column or a flash drum is preferably used. As the distillation column, a plate column or a packed column is used, with a plate column being preferred. When a distillation column is used as the separation equipment, the temperature and pressure are typically set so that unreacted isobutylene vaporizes and tertiary butyl alcohol liquefies. The column top temperature is preferably 20 to 70°C, and the column bottom temperature is preferably 100 to 160°C. The column top pressure is preferably 0.25 to 0.9 MPa (G). In this manner, tertiary butyl alcohol can be produced with a high isobutylene conversion rate while reducing equipment costs and production costs.

[0027] The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to these examples. In the examples and comparative examples, "parts" means parts by mass. The reaction apparatus used was that shown in Figure 1. Each reactor was an adiabatic fixed-bed reactor.

[0028] (Average Linear Velocity of Raw Material Liquid) The average linear velocity of the raw material liquid on an empty column basis was calculated from the volumetric flow rate of the raw material liquid supplied to the reactor by the following formula (I): Average linear velocity of raw material liquid (m / hr) = Volumetric flow rate of raw material liquid (m ３ / hr) / cross-sectional area of ​​reactor (m ２ ) (I) The cross-sectional area of ​​the reactor does not include the inserts in the reactor.

[0029] (Vw) Vw was determined by the following procedure: Using Aspen Plus manufactured by Aspen Technology, the density D (mol / m ３ ), the density Dw (mol / m ３ ) and the density Do (mol / m ３) was calculated. The outlet temperature and pressure of the first reactor 5 were used as the temperature and pressure of fluid A. Next, the obtained values ​​of D, Dw, and Do were used to solve the simultaneous equations consisting of the following formulas (II) and (III) to calculate the volume Vw (vol %) of the water phase in fluid A relative to the total volume of fluid A, and the volume Vi (vol %) of the isobutylene phase in fluid A relative to the total volume of fluid A. D=Dw×Vw / 100+Do×Vo / 100 (II) Vw+Vi=100 (III)

[0030] (Amount of Reboiler Heating Steam) The amount of reboiler heating steam was determined by measuring the amount of steam supplied to the reboiler 12 with a flow meter.

[0031] (Calculation of isobutylene conversion rate) Products in the examples and comparative examples were analyzed using gas chromatography (Shimadzu Corporation GC-2014, column: ULBON HR-20M 50 m, diameter: 0.32 mm, film thickness: 0.25 μm). From the results of gas chromatography, the isobutylene conversion rate was calculated using the following formula: Isobutylene conversion rate (%) = M2 / M1 × 100 In the above formula, M1 is the number of moles of isobutylene supplied per unit time, and M2 is the number of moles of isobutylene reacted per unit time.

[0032] Example 1 Using the reaction apparatus shown in FIG. 1 , Amberlyst 15 manufactured by DuPont was packed as the cation exchange resin. Fixed-bed reactors were used as the first reactor 5, second reactor 7, and third reactor 9, and the amount of cation exchange resin packed was 100 parts in the first reactor 5 and 50 parts in the second reactor 7 and third reactor 9. A raw material liquid having an isobutylene concentration of 12.0 mol%, a water concentration of 33.6 mol%, and a TBA concentration of 29.8 mol% was supplied to the first reactor 5 so that the average linear velocity in the first reactor 5 was the value shown in Table 1. The raw material liquid contained recycled TBA, and the Mi / Miii ratio was 4.15. The reactor inlet temperature of the first reactor 5 was adjusted to 52.2°C, and the hydration reaction of isobutylene was carried out under the conditions of a reactor outlet temperature of 65.0°C, a pressure of 0.876 MPa (G), and an average residence time of 0.634 hours. Next, 30.3 mass% of the reaction product obtained in the first reactor 5 was supplied to the second reactor 7. In the second reactor 7, the reactor inlet temperature was adjusted to 50.0°C, and the isobutylene hydration reaction was carried out under the conditions of a reactor outlet temperature of 53.8°C, a pressure of 0.804 MPa (G), and an average residence time of 1.05 hours. Next, the entire amount of the reaction product obtained in the second reactor 7 was supplied to the third reactor 9. In the third reactor 9, the reactor inlet temperature was adjusted to 53.1°C, and the isobutylene hydration reaction was carried out under the conditions of a reactor outlet temperature of 56.3°C, a pressure of 0.800 MPa (G), and an average residence time of 1.04 hours. The Vw in the first reactor 5 and the total isobutylene conversion in all reactors are shown in Table 1. The TBA-containing reaction product obtained from the third reactor 9 was supplied to a TBA separation column 10, where unreacted isobutylene was separated by distillation to obtain an aqueous TBA solution with a TBA concentration of 61.1 mol %. The amount of reboiler heating steam required to produce 1,000 parts of this aqueous TBA solution is shown in Table 1.

[0033] Example 2 The reaction apparatus, cation exchange resin, and its packing amount were the same as in Example 1. A raw material liquid having an isobutylene concentration of 11.7 mol%, a water concentration of 31.4 mol%, and a TBA concentration of 30.0 mol% was supplied to the first reactor 5 so that the average linear velocity in the first reactor 5 was the value shown in Table 1. The raw material liquid contained recycled TBA, and the Mi / Miii ratio was 4.34. The reactor inlet temperature of the first reactor 5 was adjusted to 52.7°C, and the isobutylene hydration reaction was carried out under the conditions of a reactor outlet temperature of 64.9°C, a pressure of 0.875 MPa (G), and an average residence time of 0.618 hours. Next, 30.0 mass% of the reaction product obtained in the first reactor 5 was supplied to the second reactor 7. In the second reactor 7, the reactor inlet temperature was adjusted to 50.0°C, and the isobutylene hydration reaction was carried out under the conditions of a reactor outlet temperature of 53.3°C, a pressure of 0.805 MPa (G), and an average residence time of 1.04 hours. The entire reaction product obtained in the second reactor 7 was then supplied to the third reactor 9. In the third reactor 9, the reactor inlet temperature was adjusted to 52.9°C, and the isobutylene hydration reaction was carried out under the conditions of a reactor outlet temperature of 55.5°C, a pressure of 0.800 MPa (G), and an average residence time of 1.03 hours. The Vw in the first reactor 5 and the total isobutylene conversion in all reactors are shown in Table 1. The TBA-containing reaction product obtained from the third reactor 9 was supplied to a TBA separation column 10, where unreacted isobutylene was separated by distillation to obtain an aqueous TBA solution with a TBA concentration of 63.9 mol%. The amount of reboiler heating steam required to produce 1,000 parts of the aqueous TBA solution is shown in Table 1.

[0034] Example 3 The reaction apparatus, cation exchange resin, and its packing amount were the same as in Example 1. A raw material liquid having an isobutylene concentration of 16.8 mol%, a water concentration of 31.2 mol%, and a TBA concentration of 18.8 mol% was supplied to the first reactor 5 so that the average linear velocity in the first reactor 5 was the value shown in Table 1. The raw material liquid did not contain recycled TBA, and the Mi / Miii ratio was 2.22. The reactor inlet temperature of the first reactor 5 was adjusted to 49.2°C, and the isobutylene hydration reaction was carried out under the conditions of a reactor outlet temperature of 65.0°C, a pressure of 0.860 MPa (G), and an average residence time of 0.642 hours. Next, 27.1 mass% of the reaction product obtained in the first reactor 5 was supplied to the second reactor 7. In the second reactor 7, the reactor inlet temperature was adjusted to 50.0°C, the reactor outlet temperature was 58.8°C, the pressure was 0.797 MPa (G), and the average residence time was 1.18 hours, whereby the hydration reaction of isobutylene was carried out. The entire amount of the reaction product obtained in the second reactor 7 was then supplied to the third reactor 9. In the third reactor 9, the reactor inlet temperature was adjusted to 50.0°C, the reactor outlet temperature was 54.0°C, the pressure was 0.800 MPa (G), and the average residence time was 1.18 hours, whereby the hydration reaction of isobutylene was carried out. The Vw in the first reactor 5 and the total isobutylene conversion in all reactors are shown in Table 1. The TBA-containing reaction product obtained from the third reactor 9 was supplied to a TBA separation column 10, where unreacted isobutylene was separated by distillation, yielding an aqueous TBA solution with a TBA concentration of 64.6 mol%. The amount of reboiler heating steam required to produce 1,000 parts of the aqueous TBA solution is shown in Table 1.

[0035] Example 4 The reaction apparatus, cation exchange resin, and its packing amount were the same as in Example 1. A raw material liquid having an isobutylene concentration of 16.0 mol%, a water concentration of 32.4 mol%, and a TBA concentration of 22.7 mol% was supplied to the first reactor 5 so that the average linear velocity in the first reactor 5 was the value shown in Table 1. The raw material liquid contained recycled TBA, and the Mi / Miii ratio was 3.50. The reactor inlet temperature of the first reactor 5 was adjusted to 54.6°C, and the isobutylene hydration reaction was carried out under the conditions of a reactor outlet temperature of 64.9°C, a pressure of 0.903 MPa (G), and an average residence time of 0.482 hours. Next, 23.3 mass% of the reaction product obtained in the first reactor 5 was supplied to the second reactor 7. In the second reactor 7, the reactor inlet temperature was adjusted to 50.0°C, and the isobutylene hydration reaction was carried out under the conditions of a reactor outlet temperature of 61.2°C, a pressure of 0.807 MPa (G), and an average residence time of 1.05 hours. The entire reaction product obtained in the second reactor 7 was then supplied to the third reactor 9. In the third reactor 9, the reactor inlet temperature was adjusted to 53.0°C, and the isobutylene hydration reaction was carried out under the conditions of a reactor outlet temperature of 58.3°C, a pressure of 0.800 MPa (G), and an average residence time of 1.04 hours. The Vw in the first reactor 5 and the total isobutylene conversion in all reactors are shown in Table 1. The TBA-containing reaction product obtained from the third reactor 9 was supplied to a TBA separation column 10, where unreacted isobutylene was separated by distillation to obtain an aqueous TBA solution with a TBA concentration of 63.5 mol%. The amount of reboiler heating steam required to produce 1,000 parts of the aqueous TBA solution is shown in Table 1.

[0036] Example 5 The reaction apparatus, cation exchange resin, and its packing amount were the same as in Example 1. A raw material liquid having an isobutylene concentration of 14.6 mol%, a water concentration of 28.0 mol%, and a TBA concentration of 20.6 mol% was supplied to the first reactor 5 so that the average linear velocity in the first reactor 5 was the value shown in Table 1. The raw material liquid did not contain recycled TBA, and the Mi / Miii ratio was 4.71. The reactor inlet temperature of the first reactor 5 was adjusted to 58.6°C, and the isobutylene hydration reaction was carried out under the conditions of a reactor outlet temperature of 65.0°C, a pressure of 1.06 MPa (G), and an average residence time of 0.425 hours. Next, 14.2 mass% of the reaction product obtained in the first reactor 5 was supplied to the second reactor 7. In the second reactor 7, the reactor inlet temperature was adjusted to 50.0°C, the reactor outlet temperature was 62.0°C, the pressure was 0.870 MPa (G), and the average residence time was 1.52 hours, whereby the hydration reaction of isobutylene was carried out. The entire amount of the reaction product obtained in the second reactor 7 was then supplied to the third reactor 9. In the third reactor 9, the reactor inlet temperature was adjusted to 52.0°C, the reactor outlet temperature was 56.2°C, the pressure was 0.841 MPa (G), and the average residence time was 1.52 hours, whereby the hydration reaction of isobutylene was carried out. The Vw in the first reactor 5 and the total isobutylene conversion in all reactors are shown in Table 1. The TBA-containing reaction product obtained from the third reactor 9 was supplied to a TBA separation column 10, where unreacted isobutylene was separated by distillation, yielding an aqueous TBA solution with a TBA concentration of 62.6 mol%. The amount of reboiler heating steam required to produce 1,000 parts of the aqueous TBA solution is shown in Table 1.

[0037] Comparative Example 1 The reaction apparatus, cation exchange resin, and its packing amount were the same as in Example 1. A raw material liquid having an isobutylene concentration of 12.2 mol%, a water concentration of 33.8 mol%, and a TBA concentration of 32.6 mol% was supplied to the first reactor 5 so that the average linear velocity in the first reactor 5 was the value shown in Table 1. The raw material liquid contained recycled TBA, and the Mi / Miii ratio was 4.92. The reactor inlet temperature of the first reactor 5 was adjusted to 52.4°C, and the isobutylene hydration reaction was carried out under the conditions of a reactor outlet temperature of 64.8°C, a pressure of 0.885 MPa (G), and an average residence time of 0.617 hours. Next, 31.0 mass% of the reaction product obtained in the first reactor 5 was supplied to the second reactor 7. In the second reactor 7, the reactor inlet temperature was adjusted to 50.0°C, the reactor outlet temperature was 54.1°C, the pressure was 0.812 MPa (G), and the average residence time was 0.999 hours, whereby the hydration reaction of isobutylene was carried out. The entire amount of the reaction product obtained in the second reactor 7 was then supplied to the third reactor 9. In the third reactor 9, the reactor inlet temperature was adjusted to 50.0°C, the reactor outlet temperature was 53.2°C, the pressure was 0.800 MPa (G), and the average residence time was 0.999 hours, whereby the hydration reaction of isobutylene was carried out. In the first reactor 5, the fluid A was in a homogeneous phase, and contained neither an isobutylene phase nor a water phase. The total isobutylene conversion in all reactors is shown in Table 1. The TBA-containing reaction product obtained from the third reactor 9 was supplied to the TBA separation column 10, where unreacted isobutylene was separated by distillation, yielding an aqueous TBA solution with a TBA concentration of 62.5 mol%. The amount of reboiler heating steam required to produce 1,000 parts of the aqueous TBA solution is shown in Table 1.

[0038] Comparative Example 2 The reaction apparatus, cation exchange resin, and its packing amount were the same as in Example 1. A raw material liquid having an isobutylene concentration of 12.0 mol%, a water concentration of 35.4 mol%, and a TBA concentration of 31.9 mol% was supplied to the first reactor 5 so that the average linear velocity in the first reactor 5 was the value shown in Table 1. The raw material liquid contained recycled TBA, and the Mi / Miii ratio was 4.71. The reactor inlet temperature of the first reactor 5 was adjusted to 52.6°C, and the isobutylene hydration reaction was carried out under the conditions of a reactor outlet temperature of 65.3°C, a pressure of 0.889 MPa (G), and an average residence time of 0.617 hours. Next, 31.7 mass% of the reaction product obtained in the first reactor 5 was supplied to the second reactor 7. In the second reactor 7, the reactor inlet temperature was adjusted to 50.0°C, the reactor outlet temperature was 53.4°C, the pressure was 0.815 MPa (G), and the average residence time was 0.978 hours, whereby the hydration reaction of isobutylene was carried out. The entire amount of the reaction product obtained in the second reactor 7 was then supplied to the third reactor 9. In the third reactor 9, the reactor inlet temperature was adjusted to 50.0°C, the reactor outlet temperature was 53.1°C, the pressure was 0.800 MPa (G), and the average residence time was 0.978 hours, whereby the hydration reaction of isobutylene was carried out. In the first reactor 5, the fluid A was in a homogeneous phase, and contained neither an isobutylene phase nor a water phase. The total isobutylene conversion in all reactors is shown in Table 1. The TBA-containing reaction product obtained from the third reactor 9 was supplied to the TBA separation column 10, where unreacted isobutylene was separated by distillation, yielding an aqueous TBA solution with a TBA concentration of 61.9 mol%. The amount of reboiler heating steam required to produce 1,000 parts of the TBA aqueous solution is shown in Table 1. <Comparative Example 3> The reaction apparatus, cation exchange resin, and its packing amount were the same as in Example 1. A raw material liquid having an isobutylene concentration of 13.7 mol%, a water concentration of 34.1 mol%, and a TBA concentration of 29.4 mol% was supplied to the first reactor 5 so that the average linear velocity in the first reactor 5 was the value shown in Table 1. The raw material liquid contained recycled TBA, and the Mi / Miii ratio was 3.79. The reactor inlet temperature of the first reactor 5 was adjusted to 51.1°C, and the isobutylene hydration reaction was carried out under the conditions of a reactor outlet temperature of 65.1°C, a pressure of 0.902 MPa (G), and an average residence time of 0.610 hours. Next, 35.0 mass% of the reaction product obtained in the first reactor 5 was supplied to the second reactor 7.In the second reactor 7, the reactor inlet temperature was adjusted to 50.0°C, the reactor outlet temperature was 54.0°C, the pressure was 0.828 MPa (G), and the average residence time was 0.873 hours, whereby the hydration reaction of isobutylene was carried out. The entire amount of the reaction product obtained in the second reactor 7 was then supplied to the third reactor 9. In the third reactor 9, the reactor inlet temperature was adjusted to 50.0°C, the reactor outlet temperature was 53.3°C, the pressure was 0.800 MPa (G), and the average residence time was 0.873 hours, whereby the hydration reaction of isobutylene was carried out. The Vw in the first reactor 5 and the total isobutylene conversion in all reactors are shown in Table 1. The TBA-containing reaction product obtained from the third reactor 9 was supplied to a TBA separation column 10, where unreacted isobutylene was separated by distillation, yielding an aqueous TBA solution with a TBA concentration of 61.4 mol%. The amount of reboiler heating steam required to produce 1,000 parts of the aqueous TBA solution is shown in Table 1.

[0039]

[0040] As shown in Table 1, in Examples 1 to 5, in which the average linear velocity and Vw of the raw material liquid satisfied the specified conditions, TBA was produced at a higher isobutylene conversion rate than in the Comparative Example. Furthermore, the amount of reboiler heating steam in the TBA separation column was less than in the Comparative Example, demonstrating that production costs can be reduced. Furthermore, since a step of separating TBA carboxylic acid esters, as in the conventional method, is not required, equipment costs can be reduced.

[0041] According to the present invention, tertiary butyl alcohol can be obtained at a high conversion rate while reducing equipment costs and production costs.

[0042] 1: Isobutylene supply port 2: Water supply port 3: Pump 4: Feedstock cooler 5: First reactor 6: Feedstock cooler 7: Second reactor 8: Feedstock cooler 9: Third reactor 10: TBA separation column 11: Condenser 12: Reboiler 13: Unreacted isobutylene outlet 14: TBA outlet 15: TBA circulation line

Claims

1. A method for producing tertiary butyl alcohol, comprising: (i) supplying a raw material liquid containing isobutylene and water to a reactor having a cation exchange resin; (ii) producing a reaction product containing tertiary butyl alcohol by a hydration reaction of isobutylene in the reactor, In the step (ii), the average linear velocity of the raw material liquid on an empty column basis calculated by the following formula (I) is 5 m / hr or more, Average linear velocity of the raw material liquid (m / hr) = Volumetric flow rate of the raw material liquid (m ３ / hr) / cross-sectional area of ​​reactor (m ２ ) (I) A method for producing tertiary butyl alcohol, wherein the volume (Vw) of the aqueous phase in the fluid (fluid A) in the reactor is 4 to 12 volume % relative to the total volume of the fluid A.

2. 2. The method for producing tertiary butyl alcohol according to claim 1, wherein in the step (ii), the average linear velocity of the raw material liquid on an empty column basis is 5 to 29 m / hr.

3. 2. The method for producing tertiary butyl alcohol according to claim 1, wherein in the step (ii), the average linear velocity of the raw material liquid on an empty column basis is 7 to 13 m / hr.

4. 2. The method for producing tertiary butyl alcohol according to claim 1, wherein in the step (ii), Vw is 5 to 10% by volume.

5. 2. The method for producing tertiary butyl alcohol according to claim 1, wherein in the step (ii), the outlet temperature of the reactor is 75°C or less.

6. (iii) further comprising a step of separating unreacted isobutylene from the reaction product containing tertiary butyl alcohol produced in the step (ii) to produce tertiary butyl alcohol; The method for producing tertiary butyl alcohol according to any one of claims 1 to 5.

7. The amount of tertiary butyl alcohol supplied to the reactor per unit time in the step (i) 7. The method for producing tertiary butyl alcohol according to claim 6, wherein Mi (mol / hr) is the amount of tertiary butyl alcohol produced in the step (iii) per unit time, and Miii (mol / hr) is the amount of tertiary butyl alcohol produced in the step (iii) per unit time.

8. The method for producing tertiary butyl alcohol according to claim 7, wherein Mi / Miii is 1 to 5.