JP3757969B2 - Production method of tertiary alcohol - Google Patents

Description

  The present invention relates to a polymer having a sulfonic acid group soluble in water and / or olefin, such as polystyrene sulfonic acid, from a sulfonate of the polymer, using a porous strong acid cation exchange resin. And a method for industrially producing a tertiary alcohol using a polymer having a sulfonic acid group as a catalyst.

  Tertiary alcohol is important as various industrial raw materials as well as industrial chemicals and solvents. For example, tert-butyl alcohol is used in large quantities as a raw material for producing methyl tert-butyl ether and methyl methacrylate. .

  Conventionally, tertiary alcohols are produced by olefin hydration using a catalyst. Conventional production methods are usually carried out by a liquid phase reaction, and can be divided into two types, a heterogeneous catalyst method using a solid catalyst and a homogeneous catalyst method using an aqueous acid catalyst solution.

  As the heterogeneous catalyst method, a method using a strongly acidic ion exchange resin as a catalyst is known (for example, see Patent Document 1). In this method, since the catalyst is an insoluble solid resin and the substrate olefin and water are generally non-uniform, the contact is insufficient and the activity is low. Therefore, a method of adding a large amount of an organic acid such as acetic acid to the liquid phase to make the liquid phase uniform and increasing the speed of the hydration reaction is used. However, in this method, the produced tertiary alcohol and the organic acid often easily form an organic acid ester in the presence of a strongly acidic ion exchange resin. Therefore, an extra ester separation / recovery step is required, and the process is difficult to avoid. In this method, the ion exchange resin is usually suspended and used in a batch reaction system. Therefore, the olefin hydration reaction proceeds only up to the chemical equilibrium conversion rate, and it is difficult to obtain a high olefin conversion rate.

  On the other hand, as the homogeneous catalyst method, sulfuric acid, heteropolyacid (for example, see Patent Document 2), paratoluenesulfonic acid (for example, see Patent Document 3) and the like are disclosed as catalysts. Although these catalysts all have excellent catalytic activity, the reaction product and the catalyst form a homogeneous phase because they are homogeneous catalysts. Therefore, it is necessary to separate the produced tertiary alcohol and the aqueous catalyst solution. Usually, the tertiary alcohol is separated and recovered by distillation, but at that time, the reverse reaction and the production of by-products are caused, and the yield is reduced.

  For this reason, in the homogeneous catalyst method, a separation method other than the distillation method has been proposed as a method for separating the product tertiary alcohol from the catalyst. For example, using a heteropoly acid as a catalyst, starting from an olefin containing a hydrocarbon that is inert to the hydration reaction, adding a large amount of a tertiary alcohol to the reaction system, or adding a specific inorganic salt to the reaction system A method for separating the organic phase containing the generated tertiary alcohol and the aqueous phase containing the catalyst is disclosed (for example, see Patent Document 4). However, this method requires the use of an olefin containing a hydrocarbon inert to the hydration reaction as a raw material, and a large amount of a tertiary alcohol is added to the reaction system in advance. Therefore, the olefin that can be used as a raw material is limited, and since it is necessary to add a large amount of tertiary alcohol in advance, the reaction rate easily decreases due to the reverse reaction, and the amount of recycled tertiary alcohol increases. Cause inconvenience. In addition, since a specific inorganic salt is added to the reaction system, the reaction system becomes complicated and a problem of corrosion occurs.

  On the other hand, a polymer having a sulfonic acid group is conventionally obtained by ion exchange of a polymer having a sulfonate. However, since the polymer has a large molecular weight and low diffusibility, the polymer cannot be sufficiently contacted with the ion exchange resin, and there is a problem that the ion exchange is difficult to proceed in producing the catalyst. For example, an example using a gel type or porous type cation exchange resin (Amberlite IR-120B) having a crosslinking degree of 2 to 20% as an ion exchange resin is disclosed (for example, refer to Patent Document 5). . In this disclosed embodiment, the time required for ion exchange is long, and a large amount of ion exchange resin is required. As a result, it is inevitable that the cost will be high. This method also has a problem that it is difficult to obtain a polymer having a high sulfonic acid group concentration and a high exchange rate of the metal cation of the polymer sulfonate.

Japanese Examined Patent Publication No. 56-22855

Japanese Patent Publication No.58-39806 Japanese Examined Patent Publication No. 62-12208 Japanese Patent Publication No.58-39806 Japanese Patent Laid-Open No. 60-15408

  The present invention has been made in view of the above prior art, and its object is to provide a method for producing a tertiary alcohol with high activity, high yield and economically by hydration reaction of olefin, and a catalyst used therefor. It is to provide a manufacturing method.

  The present inventors diligently studied to solve the above problems. As a result, when a polymer having a sulfonic acid group soluble in water and / or olefin is used as a catalyst, the hydration reaction of the olefin proceeds efficiently and in high yield, and the produced tertiary alcohol and catalyst Was separated by a simple operation, and it was found that the desired tertiary alcohol was obtained, and the present invention was completed.

  That is, the present invention has a sulfonic acid group characterized by using a porous strong acidic cation exchange resin in a method for obtaining a polymer having a sulfonic acid group by ion exchange of a polymer having a sulfonate salt. It is a manufacturing method of a polymer. Furthermore, the present invention is a method for producing a tertiary alcohol, characterized in that olefin is hydrated using a polymer having a sulfonic acid group soluble in water and / or olefin as a catalyst. The present invention is described in further detail below.

  First, a method for producing a polymer having a sulfonic acid group, which is the first invention of the present application, will be described. In the present invention, a polymer having a sulfonate is ion-exchanged using a porous strong acid cation exchange resin to obtain a polymer having a sulfonic acid group.

  Examples of the polymer having a sulfonate used as a raw material in the present invention include polystyrene sulfonate, polynaphthalene sulfonate, polyvinyl sulfonate, styrene sulfonate-maleic anhydride copolymer, naphthalene sulfonate-formalin. A copolymer etc. can be illustrated. In polymers having these sulfonates, a part of the polymer skeleton is substituted with an alkyl group, an alkoxy group, a halogen group, a carboxyl group, an ester group, a nitrile group, a nitro group, or an N-alkylamide group. May be. The polymer having these sulfonates is more preferably polystyrene sulfonate, polyvinyl sulfonate, or a mixture thereof.

  Examples of the sulfonate cation include lithium, sodium, potassium, cesium, magnesium, calcium, beryllium, aluminum, nickel, copper, zinc, cobalt, tellurium, vanadium, titanium, iron, chromium, manganese, ammonium, and silver. More preferred are sodium and potassium.

  Usually, a polymer having a raw material sulfonate is handled as an aqueous solution. Although the concentration is not particularly limited, 10 to 50 wt% is appropriate because the viscosity of the aqueous solution increases at a high concentration and concentrating operation is necessary at a low concentration. If necessary, other organic solvents that are soluble in the polymer aqueous solution, such as alcohols, ketones, ethers, and the like can be added.

  The ion exchange resin used in the catalyst preparation of the present invention is a porous strongly acidic cation exchange resin based on, for example, a styrene-divinylbenzene copolymer, and examples of the exchange group include a sulfonic acid group. It is done. Generally, strongly acidic ion exchange resins are classified into a gel type and a porous type depending on the physical porous state. The gel type is an ion exchange resin having only micropores that are pores generated by swelling, and the porous type is an ion exchange resin having macropores that are physical pores that do not disappear even in a dry state other than micropores. . As the porous ion exchange resin, MP type (macroporous type resin), MR type (resin having a huge network structure) and the like are further known (for example, Petertec P23, Vol. 10, No. 12, 1987). .

  The porous strong acid cation exchange resin used in the present invention is not particularly limited in its production method. For example, a granular copolymer of styrene and divinylbenzene can be produced by sulfonating a base resin with sulfuric acid. Among these, the resin used as the base of the MP type or MR type is characterized by the solvent used for production. That is, the MP-type resin is produced by adding a water-insoluble organic solvent that sufficiently dissolves the monomer and sufficiently swells the produced polymer, for example, an aromatic hydrocarbon such as benzene and toluene to the polymerization system. The MR type resin is produced by adding a water-insoluble organic solvent, such as a secondary alcohol, which dissolves the monomer well but does not swell the produced polymer.

  As a porous type cation exchange resin that can be used in the present invention, commercially available examples include, for example, Amberlyst 15E (manufactured by Organo Corporation) as MR type, and Diaion PK220 (manufactured by Mitsubishi Kasei Co., Ltd.) as MP type. ), Duolite C-264 (manufactured by Sumitomo Chemical Co., Ltd.) and the like.

  Porous strongly acidic ion exchange resins have many macropores that are physical pores that do not disappear even in a dry state. For this reason, when a porous strongly acidic ion exchange resin is used, a polymer electrolyte having a large molecular weight such as polystyrene sulfonate easily diffuses into the inside of the ion exchange resin through many macropores. It is presumed that this exchange group can be used effectively, and ion exchange can be performed in a short time with a small amount of ion exchange resin.

  In addition, the ion exchange resin used in the present invention is suitably a spherical one having a particle diameter of about 0.3 to 1.0 mm.

  According to the present invention, the ion exchange method is not particularly limited and can be carried out by a usual method. For example, a method in which a necessary amount of a porous strong acid cation exchange resin is directly added to a polymer solution having a sulfonate, and the mixture is stirred for a predetermined time. There is a method of flowing a predetermined amount of the polymer solution. The temperature at this time can be usually room temperature, but if necessary, it can be heated to around 120 ° C. Furthermore, if necessary, a polymer having a sulfonic acid group can be obtained with a higher ion exchange rate by repeating the ion exchange reaction. In this way, a polymer solution having a desired sulfonic acid group can be obtained.

  In the polymer having a sulfonic acid group as a catalyst, a sulfonate may remain in a part thereof. The proportion of the sulfonate remaining in the polymer having a sulfonic acid group as a catalyst is preferably 80% or less. Above this, the activity of the olefin hydration reaction is significantly reduced, which is not preferable.

  The porous strong acid cation exchange resin used in the present invention can be repetitively used because it is easily regenerated by flowing a normal method after use, for example, hydrochloric acid or sulfuric acid aqueous solution.

  Next, an olefin hydration reaction according to the second invention of the present application will be described. In the present invention, the polymer having a sulfonic acid group produced by the first invention of the present application can be used as a catalyst, but a polymer having a sulfonate is obtained by other methods, for example, a known polymerization or copolymerization method. Thereafter, a polymer having a sulfonic acid group may be produced by a general method such as ion exchange or electrophoresis. Further, after a polymer having no sulfonic acid group is produced, a sulfonic acid group may be introduced.

  The olefin used as a reaction raw material of the present invention is isobutene, α-methylstyrene, isoprene and / or a mixture thereof. These olefins may contain a hydrocarbon mixture inert to the hydration reaction. For example, the isobutene may be a mixture optionally containing a saturated or unsaturated hydrocarbon having 4 carbon atoms such as 1-butene, cis-2-butene, trans-2-butene, n-butane, and isobutane. In addition, α-methylstyrene may contain aromatic hydrocarbons such as benzene, toluene, xylene, cumene, and the like. Examples of these olefins containing hydrocarbons that are inert to the hydration reaction include, for example, isobutene, by-product C4 fraction of fluid catalytic cracking reaction of petroleum, catalytic dehydrogenation fraction of n-butane, and the like. It is done. Further, among the naphtha decomposition products, so-called spent BB obtained after removing butadiene from a fraction having 4 carbon atoms can be mentioned.

  The polymer having a sulfonic acid group needs to be soluble in water or olefin, and those having a weight average molecular weight of 500 to 5,000,000 can be used. More preferably, the molecular weight is 1,000 to 1,000,000. The concentration of the polymer having a sulfonic acid group used as a catalyst is not particularly limited, but can be used in a range from 5% by weight or more to saturated solubility. At this time, the solvent of the polymer is preferably water which is also a reaction substrate. If necessary, a polymer having a sulfonic acid group and an olefin, a solvent inert to water, for example, dioxane, acetone or the like may be added, and a product tertiary alcohol is added. There is no problem.

  Although reaction temperature is not specifically limited, 10-120 degreeC, Preferably it implements in 30-100 degreeC. When the temperature is higher than 120 ° C., the equilibrium conversion rate of the olefin hydration reaction is remarkably lowered, so that the amount of tertiary alcohol produced is extremely reduced. The amount is reduced.

  In the present invention, the reaction pressure is normal pressure to 30 KG. The olefin is supplied to the reaction system as a gas or liquid. More preferably, the reaction pressure at which the olefin is present as a liquid is desirable in consideration of the hydration rate of the olefin. In this case, if necessary, the pressure can be controlled using an inert gas such as nitrogen, argon or carbon dioxide.

  As an embodiment of the present invention, any of a stirring reactor, an external circulation reactor, a column reactor, a tubular reactor, etc. can be used, and any of batch type, semi-batch type, and continuous type may be used. . Considering the process of obtaining the desired tertiary alcohol with high conversion and high purity and high productivity, countercurrent multistage continuous operation is desirable.

  In the present invention, a polymer having a sulfonic acid group that is soluble in water and / or olefin is used as a catalyst. Therefore, when the reaction solution after the reaction is allowed to stand, two-phase separation occurs. And to separate. The temperature of the two-phase separation operation is 0 to 130 ° C, preferably 20 to 100 ° C. If the amount of the tertiary alcohol produced is large, it is easily separated into two phases even at room temperature. If it is difficult to separate into two phases, it can be separated into two phases by heating. The temperature at this time may be heated to 60 ° C. or higher, and in some cases, 80 ° C. or higher. Although this operation pressure is not particularly limited, it is desirable to operate at the same pressure as the olefin hydration reaction pressure in the process.

  The layer not containing the catalyst is separated from the layer containing the catalyst with a decanter or the like. The tertiary alcohol is easily purified from the catalyst-free layer by a conventional method such as distillation. On the other hand, the layer containing the catalyst can be reused by circulating as an aqueous catalyst solution. In this two-phase separation operation, if necessary, an appropriate solvent inert to the reaction system may be added. Examples of these solvents include butanes, pentanes, hexanes, cyclohexane, benzene, toluene, xylene, and alcohols.

  Separation of the tertiary alcohol produced by the reaction and the catalyst is not limited to two-phase separation because the catalyst is a polymer soluble in water and / or olefin, and filtration through a separation membrane can also be used. Filtration methods include microfiltration, ultrafiltration, and reverse osmosis.

  Thus, the ability to separate the produced tertiary alcohol and the catalyst by two-phase separation or filtration is advantageous in the following three points.

  1) A layer containing a tertiary alcohol obtained by two-phase separation or filtration does not contain a catalyst, and does not cause a decrease in yield due to dehydration or side reaction of the tertiary alcohol, which has been a problem in conventional processes.

  2) Since the tertiary alcohol is distilled and purified by separating the aqueous layer containing the catalyst, the vacuum distillation performed in the conventional process can be avoided, and the distillation and purification at normal pressure becomes possible. Moreover, the throughput in the distillation process can be significantly reduced, and the distillation apparatus can be made smaller.

  3) Since the catalyst is separated before distillation, the catalyst is not easily deteriorated by heat, and the catalyst phase can be recycled and used as it is.

  In the present invention, the filtration / two-phase separation step is not necessarily required. For example, the tertiary alcohol may be separated directly from the reaction solution by vacuum distillation.

  Next, an example of a specific method of the present invention will be described with reference to the drawings. The raw material olefin is introduced into the reactor 1 from the line 4. On the other hand, a catalyst aqueous solution (line 7) separated and reused by the decanter 2 and a makeup amount of the catalyst aqueous solution (line 3) are combined and introduced into the reactor 1 to cause a countercurrent reaction. The reaction solution is extracted from the line 5 and led to the decanter 2 to be separated into a layer containing the catalyst and a layer not containing the catalyst. The layer containing the tertiary alcohol without containing the catalyst is sent from the line 8 to a purification tower such as distillation. The layer containing the catalyst separated by the decanter 2 is recycled to the reactor 1 from the line 7. The residual olefin after the reaction is moved from the line 6.

  According to the present invention, a tertiary alcohol can be obtained from an olefin by a hydration reaction in a high yield and economically. In addition, according to the present invention, the catalyst used at that time has a high ion exchange rate from a sulfonate to a sulfonic acid group, so that a catalyst of extremely high quality can be obtained.

  Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to these examples.

(Catalyst preparation)
Examples 1-4
200 g of polystyrene sulfonate aqueous solutions (resin content: 20 wt%) having different molecular weights and 130 g (dry weight) of Amberlyst 15E (manufactured by Organo) were mixed and stirred for 1 hour. After removing Amberlyst 15E by filtration, the amount of sodium in the filtrate was measured to determine the ion exchange rate of polystyrene sulfonic acid. The results are shown in Table 1.

Ion exchange rate (%) = 100− (amount of sodium sulfonate in the filtrate) / (amount of sulfonate groups and sodium sulfonate in the filtrate) * 100
Examples 5 and 6
After mixing 200 g of polystyrene sulfonate aqueous solutions (resin content 20 wt%) having different molecular weights and 100 g (dry weight) of Amberlyst 15E (manufactured by Organo) and stirring for 1 hour, Amberlyst 15E was removed by filtration. Thereafter, the filtrate was subjected to ion exchange again using 50 g of Amberlyst 15E. Table 1 shows the ion exchange rate of the obtained polystyrene sulfonic acid aqueous solution.

Comparative Example 1
An ion exchange reaction was carried out for 24 hours under the same conditions as in Example 1 except that the type of ion exchange resin was Amberlite IR-120 (manufactured by Organo), which is a gel type cation exchange resin. The ion exchange rate is shown in Table 1.

表から明らかなように、ポーラス型の強酸性陽イオン交換樹脂を用いた場合、ゲル型の陽イオン交換樹脂を用いた場合と比べて、ポリスチレンスルホン酸塩の分子量の大小にかかわらず、短時間で少量の樹脂を用いて、高いイオン交換率でポリスチレンスルホン酸を得ることができ、さらにイオン交換反応を繰り返すことにより、より高いイオン交換率を達成することができる。

As is clear from the table, when using a porous strong acid cation exchange resin, compared to using a gel type cation exchange resin, a shorter time is required regardless of the molecular weight of polystyrene sulfonate. With a small amount of resin, polystyrene sulfonic acid can be obtained with a high ion exchange rate, and a higher ion exchange rate can be achieved by repeating the ion exchange reaction.

Examples 7-10
The type of polymer and the amount of ion exchange resin were changed as shown in Table 2, and ion exchange was performed in the same manner as in Example 1 to obtain a catalyst.

（イソブテンの水和反応）
反応生成物は、内部標準物質としてジメトキシエタンを用い、試料をか性ソーダで中和し、ガスクロマトグラフィーにより分析した。また実施例中ではｔｅｒｔ−ブチルアルコールをＴＢＡと略す。

(Isobutene hydration reaction)
The reaction product was analyzed by gas chromatography using dimethoxyethane as an internal standard substance, neutralizing the sample with caustic soda. In the examples, tert-butyl alcohol is abbreviated as TBA.

Examples 11-13
Table 3 shows the results after 5 g of isobutene and 150 ml of various polystyrene sulfonic acid 10 wt% aqueous solutions were charged in an autoclave, sealed, heated to 70 ° C. and stirred for 2 hours. In all of Examples 11 to 13, no by-products such as diisobutene and triisobutene were detected, and the selectivity was 100%.

実施例１４
原料をイソブテンからスペントＣ４（組成は表５の通り）１６．８ｇ（イソブテン５ｇ含有）に変えた以外は実施例１１と同じ条件で反応を行った。副生のジイソブテン、セカンタリーブタノールは検出されず、８０％のイソブテン反応率、選択率１００％でＴＢＡが得られた。

Example 14
The reaction was performed under the same conditions as in Example 11 except that the raw material was changed from isobutene to 16.8 g of spent C4 (composition as shown in Table 5) (containing 5 g of isobutene). By-product diisobutene and secondary butanol were not detected, and TBA was obtained with an isobutene reaction rate of 80% and a selectivity of 100%.

Example 15
Using 50 ml of polystyrenesulfonic acid aqueous solution having a hydrogen ion concentration of 0.2 N (molecular weight: 10,000, sodium exchange rate in sulfonic acid group: 63.5%) as a catalyst, 10 g of isobutene was reacted at 60 ° C. for 30 minutes. The TBA production rate per 1 g of the catalyst was 0.470 g / hr · g-catalyst.

Comparative Example 2
The reaction was carried out under the same conditions as in Example 15 using a silicotungstic acid aqueous solution having a hydrogen ion concentration of 0.2 N as a catalyst. The rate of TBA production per gram of catalyst was 0.253 g / hr · g-catalyst.

Example 16
20 g of an aqueous solution obtained by concentrating the catalyst obtained in Example 7 to a hydrogen ion concentration of 1.2 N and 5 g of raw material isobutene were charged into an autoclave and reacted at 70 ° C. for 3 hours. After the reaction, the pressure was returned to normal pressure, and unreacted isobutene was purged. The reaction solution was transferred to a separatory funnel and kept at 25 ° C. to separate into two phases. The upper and lower layers were taken and analyzed, and the isobutene reaction rate and TBA distribution rate were determined and are shown in Table 4. By-products such as diisobutene and triisobutene were not detected, and the selectivity was 100%.

Examples 17 and 18
The reaction was carried out under the same conditions as in Example 16 except that the amount of isobutene was changed to 10 g and 20 g. Table 4 shows the results when two-phase separation was performed at 25 ° C. after purging of unreacted isobutene after the reaction. In any of Examples 17 and 18, by-products such as diisobutene and triisobutene were not detected, and TBA was obtained at a selectivity of 100%.

Examples 19 and 20
The catalyst obtained in Example 8 was charged in an autoclave as 20 g of an aqueous solution concentrated to a hydrogen ion concentration of 1.2 N and isobutene as 5 g and 10 g, respectively, and reacted at 70 ° C. for 3 hours. After purging unreacted isobutene after the reaction, the results when two phases were separated at 25 ° C. were as shown in Table 4. In all of Examples 19 and 20, no by-products such as diisobutene and triisobutene were detected, and the selectivity was 100%.

Example 21
20 g of an aqueous solution obtained by concentrating the catalyst prepared in Example 1 to a hydrogen ion concentration of 1.2 N and 10 g of isobutene were charged into an autoclave and reacted at 70 ° C. for 3 hours. After purging unreacted isobutene after the reaction, the results when the two phases were separated at 82 ° C. were as shown in Table 4. By-products such as diisobutene and triisobutene were not detected, and the selectivity was 100%.

Example 22
The reaction was performed under the same conditions as in Example 16 except that the raw material was changed from isobutene to 16.8 g of spent BB (composition as shown in Table 5) (containing 5 g of isobutene). Table 4 shows the results when two phases were separated at 25 ° C. after purging of unreacted spent BB after the reaction. By-product diisobutene and secondary butanol were not detected, and TBA was obtained at a selectivity of 100%.

Example 23
The reaction was carried out under the same conditions as in Example 17 except that the catalyst obtained in Example 9 was used. Table 4 shows the results when two-phase separation was performed at 25 ° C. after purging of unreacted isobutene after the reaction. By-products such as diisobutene and triisobutene were not detected, and TBA was obtained at a selectivity of 100%.

Example 24
The reaction was carried out under the same conditions as in Example 17 except that the catalyst obtained in Example 10 was used. Table 4 shows the results when two-phase separation was performed at 25 ° C. after purging of unreacted isobutene after the reaction. By-products such as diisobutene and triisobutene were not detected, and TBA was obtained at a selectivity of 100%.

Comparative Examples 3 and 4
The reaction was carried out under the same conditions as in Example 1 using silicotungstic acid having a hydrogen ion concentration of 1.2 N and a paratoluenesulfonic acid aqueous solution as a catalyst. After the reaction, a homogeneous solution was formed, and no two-phase separation was observed even when the temperature was increased to 90 ° C. or sodium was added as a cation. The analysis results of the homogeneous solution were as shown in Table 4. By-products such as diisobutene and triisobutene were not detected, and the selectivity was 100%.

It is explanatory drawing which showed an example of the process of the olefin hydration reaction.

Explanation of symbols

1 Reactor 2 Decanter 3 Line for moving make-up catalyst aqueous solution 4 Line for introducing raw material olefin 5 Line for moving reaction liquid 6 Line for moving residual olefin 7 Line for moving aqueous catalyst solution to be reused 8 Containing alcohol Line to move phase to purification tower

Claims (6)

A method for producing a tertiary alcohol, characterized by hydrating a olefin using a polymer having a sulfonic acid group soluble in water and / or olefin as a catalyst. The process according to claim 1, wherein the olefin is isobutene and the tertiary alcohol is tert-butanol. The method according to claim 1, wherein the polymer having a sulfonic acid group is polystyrene sulfonic acid or polyvinyl sulfonic acid. The process according to claim 1, wherein the hydration reaction of the olefin is carried out by a countercurrent reaction. 5. The production method according to claim 1, wherein the reaction solution after the hydration reaction is subjected to two-phase separation into a layer containing a catalyst and a layer not containing a catalyst. The process according to claim 1, 2, 3 or 4, wherein the reaction solution after the hydration reaction is separated into a layer containing a catalyst and a layer not containing a catalyst by filtration.

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