JP4076269B2 - Method for producing cyclic alcohol - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a process for producing a cyclic alcohol by using a crystalline metallosilicate as a catalyst and carrying out a catalytic hydration reaction of a cyclic olefin in the presence of water.
[0002]
[Prior art]
Conventionally, a solid acid catalyst such as crystalline metallosilicate is used for the hydration reaction of cyclic olefins, and the method for producing cyclic alcohols is described in “Liquid-phase hydration reaction of cyclohexene using high silica zeolite” (Nippon Kagaku). Many publications such as Journals, 1989, (3), p. 521 to 527), and Japanese Patent Application Laid-Open No. 60-104028.
There are also numerous patent applications for significant impurity effects in the reaction system.
[0003]
For example, according to Japanese Patent Laid-Open No. 63-154636, a method is proposed in which a catalytic hydration reaction is carried out in a system substantially free of organic peroxide. Among these, it is described that the organic peroxide significantly lowers the catalytic activity, and that this organic peroxide increases during storage in the tank (hereinafter referred to as Prior Art 1). Called).
According to Japanese Patent Laid-Open No. 63-250334, a method for catalytic hydration of a cyclic olefin in a reaction system in which the cyclic conjugated diene is 200 ppm or less is proposed. In addition, as its effect, it is described that a decrease in the activity of the catalyst over time is remarkably suppressed (hereinafter referred to as Prior Art 2).
[0004]
According to Japanese Patent Laid-Open No. 7-179381, a method of performing catalytic hydration using a cyclic olefin having an epoxy compound content of 300 ppm or less as a raw material has been proposed, and the effect thereof is stable for a long time compared with the conventional method. It is described that the separability of the prepared catalyst can be maintained (hereinafter referred to as Prior Art 3).
Furthermore, according to Japanese Patent Application Laid-Open No. 7-179382, a method of performing catalytic hydration using a cyclic olefin having a conjugated ketone content of 200 ppm or less as a raw material has been proposed. As a result, the life of the catalyst is greatly improved. It is described that it can be done (hereinafter referred to as Prior Art 4).
[0005]
On the other hand, it is clearly shown in the literature that the impurities described in these prior arts are mainly caused by the oxidation reaction of cyclic olefins. For example, in “Liquid-Phase Oxidations of Cyclic Alkenes” (Journal of the American Chemical Society / 87:21 / November 5, 1965 p4824 to 4832), cyclohexene hydroperoxide (described in Prior Art 1) is obtained by an oxidation reaction of cyclohexene. ), 3-hydroxycyclohexene (described in Prior Art 2), 1,2-epoxycyclohexane (described in Prior Art 3), and cyclohexenone (described in Prior Art 4).
That is, in any technique, it is necessary to prevent the raw material before entering the reaction system from being oxidized, and to prevent the raw material existing in the reaction system from being oxidized. is there.
[0006]
[Problems to be solved by the invention]
However, in any of the descriptions in the prior arts 1 to 4, as a means for removing the adverse effects of impurities, the generation of such impurities is allowed, and under the technical idea of using raw materials not containing these impurities, these cyclohexenes are used. It only exemplifies a method of removing impurities that are oxidation reaction products. That is, in the prior art, no method for fundamentally preventing or suppressing the formation of the oxidation reaction product has been described.
The production of the oxidation reaction product results in some energy consumption, for example 1) depletion of the main hydration reaction feedstock, and 2) removal, for example a distillation separation process. For this reason, in industrial implementation, establishment of the oxidation reaction product production | generation prevention and suppression method was requested | required more strongly than this oxidation reaction product removal method.
[0007]
[Means for Solving the Problems]
In response to this request, the present inventors have conducted extensive studies with the goal of suppressing or preventing the formation of the oxidation reaction product. As a result, surprisingly, in order to suppress the production of the oxidation reaction product, an oxidizing agent such as oxygen in the air and a cyclic olefin which is a flammable substance are usually used in industrial implementation. It was found that the management to the extent of avoiding the contact was inadequate. More specifically, in a chemical plant that handles a flammable substance having a relatively low flash point as in the present invention, for safety, oxygen in the air is mixed into tower tanks that handle the substance, and an explosive mixture is In order to avoid the formation, it is usual to take measures such as filling the gas phase part with an inert gas such as nitrogen, etc., and in the cyclic olefin in the present invention, the same contact prevention measures with oxygen are usually used. It is done. This means that, in the raw material cyclic olefin, measures for preventing the formation of the oxidation reaction product are adopted simultaneously with safety measures. However, in order to suppress or prevent the production of the oxidation reaction product in the entire reaction system, the above measures alone are insufficient.
[0008]
In addition to this, it is necessary to keep the oxidant concentration of water, which is another raw material of the hydration reaction, low, and other substances that may be mixed into the reaction system are also included in the oxidation. The inventors have found that it is preferable to keep the concentration of the agent low, and have completed the present invention by establishing an industrially simple method as means for achieving the low oxidizing agent concentration.
[0009]
That is, the present invention is as follows.
1) A method for producing a cyclic alcohol by conducting a catalytic hydration reaction of a cyclic olefin represented by the following general formula (2) in the presence of water using a crystalline metallosilicate represented by the following general formula (1) as a catalyst. The method for producing a cyclic alcohol characterized in that the oxidant concentration in the water is 0.03 mmol / liter or less.
qM _{2 / k} O · xSiO ₂ ・ YAl ₂ O _Three ・ (1-y) Z ₂ O _w (1)
(Wherein M represents at least one k-valent cation, O is oxygen, Si is silicon, Al is aluminum, Z is a metal other than M and aluminum, and boron, gallium, titanium, chromium, iron, zinc Represents at least one w-valent metal selected from phosphorus, vanadium, and copper, and q = 1 ± 0.5, 1 ≦ x ≦ 1000, and 0 ≦ y ≦ 1.
C _n H _2n-2-m R _m (2)
(In the formula, R is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a phenyl group or a cyclohexyl group, n is 5 to 12, and m is an integer of 1 to 4).
[0010]
2) The method for producing a cyclic alcohol as described in 1) above, wherein the oxidizing agent is oxygen.
3) The method for producing a cyclic alcohol as described in 1) or 2) above, wherein the concentration of the oxidant in the feed water for replenishing water reduced by catalytic hydration is 0.03 mmol / liter or less.
4) The method for producing a cyclic alcohol according to 3) above, wherein the supplied water is previously brought into contact with a gas not containing oxygen before being subjected to the reaction.
5) The method for producing a cyclic alcohol according to any one of 1) to 4) above, wherein the catalyst is a catalyst after being subjected to a hydration reaction for a total of 2000 hours or more.
[0011]
6) The method for producing a cyclic alcohol according to any one of 1) to 5) above, wherein the crystalline metallosilicate is a crystalline aluminosilicate.
7) The method for producing a cyclic alcohol according to any one of 1) to 6) above, wherein the cyclic olefin is cyclohexene and the cyclic alcohol is cyclohexanol.
8) The method for producing a cyclic alcohol as described in 1) to 6) above, wherein the cyclic olefin is methylcyclopentene and the cyclic alcohol is methylcyclopentanol.
9) The method for producing a cyclic alcohol as described in 7) above, wherein cyclohexene, which is a cyclic olefin, is produced by a partial hydrogenation reaction of benzene.
[0012]
Hereinafter, specific embodiments of the present invention will be described.
The crystalline metallosilicate used in the present invention is a crystalline metallosilicate containing at least one metal selected from aluminum, boron, gallium, titanium, chromium, iron, zinc, phosphorus, vanadium, and copper. For example, the composition represented by the molar ratio of the oxide of anhydride is represented by the general formula (1).
[0013]
In the general formula (1), M is a cation in the crystalline metallosilicate, preferably a proton, IB, IIA, IIB, IIIA, IIIB, IVB, VB, VIB, VIIB on the periodic table, Group VIII metal cations, more preferably protons. Z is a metal other than M and aluminum, and is at least one metal selected from boron, gallium, titanium, chromium, iron, zinc, phosphorus, vanadium, and copper. These are crystalline metallosilicates. It is a metal that is taken into the crystal during hydrothermal synthesis and remains in the crystalline metallosilicate in the subsequent ion exchange operation. Among the remaining metals, boron, gallium, titanium, chromium and iron are particularly preferable.
[0014]
Specific examples of the catalyst include mordenite, borojasite, clinobutyrolite, L-type zeolite, chabasite, erionite, ferriferrite, crystalline aluminosilicate such as ZSM zeolite announced by Mobil Corporation, In addition to aluminum, crystalline aluminometallosilicates that also contain elements such as boron, gallium, titanium, chromium, iron, zinc, phosphorus, vanadium, copper, metallosilicates such as gallosilicates and borosilicates that do not substantially contain aluminium, etc. Is mentioned.
[0015]
Further, AZ-1, TPZ-3, Nu-10 (described in JP-A-60-104030), Nu-3 (described in JP-A-57-3714), Nu-5 (JP-A-5757). Crystalline aluminosilicates such as Nu-6 (described in JP-A-57-123817) are also effective.
Further, these metallosilicates are also useful when used in combination of two or more.
[0016]
The crystalline metallosilicate used in the present invention preferably has a primary particle size of 0.5 μm or less, more preferably 0.1 μm or less, still more preferably 0.05 μm or less. The lower limit of the particle size is defined by the term “crystallinity”. Crystals are those in which atoms are regularly and periodically arranged according to a certain symmetry, and diffraction phenomena due to X-rays are observed (Kyoritsu Shuppan Co., Ltd., Chemistry Dictionary, 1963, Vol. 3, Pp. 349, “Crystals”). Therefore, for a certain period to occur and the X-ray diffraction phenomenon to be recognized, there is a certain finite size based on the crystal structure. Therefore, it can be said that the crystalline metallosilicate used in the present invention preferably has an X-ray diffraction phenomenon and a primary particle diameter of 0.5 μm or less. There are various shapes of these primary particles, but the primary particle size referred to in the present invention is the measured value obtained by measuring the narrowest diameter of the fine particles to be measured as viewed with a scanning electron microscope. The number of the following is at least 50% of the total. In this case, if the primary particle diameter is 0.5 μm or less, it is effective even if the diameter of the secondary particles formed by such aggregation is increased.
[0017]
In addition, side reactions such as isomerization and polymerization occur in the hydration reaction of cyclic olefins. For example, in the hydration reaction of cyclohexene, side reactions such as methylcyclopentenes, methylcyclopentanols, dicyclohexyl ether, and bicyclohexyl. Living creatures produce. In order to suppress this side reaction and obtain a cyclic alcohol with good yield, for example, it is also effective to use crystalline aluminosilicate ZSM-5 as a catalyst as disclosed in JP-A-58-194828. . Crystalline aluminosilicate ZSM-5 is a zeolite developed by Mobil Oil (see U.S. Pat. No. 3,702,886), and the molar ratio of silica and alumina constituting the crystal is 20 or more, A zeolite having three-dimensional pores having an oxygen 10-membered ring inlet.
[0018]
On the other hand, the cyclic olefin used in the catalytic hydration reaction of the present invention is a compound represented by the general formula (2), for example, cyclopentene, cyclohexene, cycloheptene, cyclooctene, cyclononene, cyclodecene, cycloundecene, Examples thereof include cyclododecene, methylcyclopentene, methylcyclohexene, dimethylcyclohexene, trimethylcyclohexene, tetramethylcyclohexene, phenylcyclohexene, and the like, and mixtures thereof are also useful.
[0019]
These cyclic olefins are hydrated to produce the corresponding cyclic alcohols. Although these cyclic olefins depend on the production method, pure ones are not necessarily obtained. For example, in the case of cyclohexene produced by partial hydrogenation of benzene, as impurities, 1) benzene, cyclohexane, which is a raw material or by-product of a hydrogenation reaction, 2) toluene, which is an impurity in the raw material benzene or its hydride, Methylcyclohexene, methylcyclohexane, norcamphane, n-pentane, n-hexane, n-heptane, xylene, ethylbenzene, styrene, 3) When using extractive distillation method for distillation separation of benzene hydrogenation reaction products, extract solvent Since this involves the addition of new components such as, it is conceivable that the components are mixed. In addition, in the case of continuously producing cyclohexanol industrially, when this cyclohexene is supplied to the hydration reactor, 4) the main product of the hydration reaction is recycled. Cyclohexanol contained in unreacted cyclohexene and methylcyclopentenes and methylcyclopentanols contained in unreacted cyclohexene which is a by-product of the hydration reaction and are recycled are added.
[0020]
As a result, in the hydration reaction system, impurities 1) to 3), methylcyclopentenes and methylcyclopentanols are present in addition to the raw materials and main products. Impurities other than these raw materials and main products a) impair the purity of the raw material in the hydration reaction, b) deterioration of oil / water separation due to the presence of components different from the raw materials and main products, and c) decrease in catalyst activity. Influence, d) It is preferable to reduce it to the lowest possible level in the previous step, because it may cause the component itself or the reaction between the components, generation of high boiling components by polymerization, blockage of piping, etc.
[0021]
The temperature of the hydration reaction is advantageous from the viewpoint of the equilibrium problem of cyclic olefin hydration reaction and the suppression of side reactions, but if the reaction temperature is too low, the reaction rate decreases and the reactor becomes larger. There is a need and it is not reasonable. Therefore, in the present invention, the reaction is carried out in the range of 50 ° C to 250 ° C, preferably 70 ° C to 200 ° C, particularly preferably in the range of 80 ° C to 150 ° C.
The reaction pressure can be applied in the range from reduced pressure to increased pressure, but in the present invention, the reaction is carried out at a pressure at which both the cyclic olefin and water, which are raw materials for the reaction, can maintain a liquid phase. Further, in accordance with the gist of the present invention, it is preferable to carry out the reaction under a pressurized condition in order to prevent air from being mixed into the hydration reaction system.
[0022]
Although the molar ratio of the reaction raw material water to the cyclic olefin can be within a wide range, if the cyclic olefin is too excessive, the conversion rate of the cyclic olefin becomes low. On the other hand, if the amount of water is excessive, the conversion rate of the cyclic olefin can be increased, but not only is it disadvantageous in terms of separation and purification of the produced cyclic alcohol, but also the reactor and the liquid-liquid separator in the subsequent process are enlarged. Need arises. However, increasing the volume of the vessel unnecessarily is not a good idea in terms of equipment production, maintenance and inspection and operation. Therefore, in this invention, the molar ratio of the cyclic olefin with respect to water has the preferable range of 0.01-100.
Further, the weight ratio of the cyclic olefin to the catalyst varies depending on conditions such as reaction temperature, reaction pressure, molar ratio of cyclic olefin and water in a continuous reaction usually carried out on an industrial scale. The weight of the catalyst is preferably in the range of 0.005 to 100 with respect to the weight of the cyclic olefin supplied to the reactor in one hour.
[0023]
As a method for separating the oil phase containing the cyclic alcohol from the reaction system, for example, in the batch method, after the reaction, the reaction system is left to perform phase separation, and the upper oil phase is taken out. In addition, in the continuous method which is an embodiment on a normal industrial scale, a part of the reaction solution is continuously taken out from the upper part of the reaction system, phase separation is performed in a stationary tank, the upper oil phase is taken out, and the lower layer The aqueous phase is returned to the reaction system. In this case, a stationary separation zone is provided inside the reactor, and phase separation is also performed inside the reactor, so that the handling work when returning the aqueous phase containing the catalyst can be omitted, and the transfer system at that time This is preferable because there is no problem of erosion.
[0024]
In order to remove the cyclic alcohol from the oil phase, a distillation method is usually used, and the unreacted cyclic olefin is preferably returned to the reaction system and reused. Further, in order to obtain a high-purity cyclic alcohol, a method of partially extracting methylcyclopentenes as a by-product in another process (described in JP-A-4-41448) and / or hydration mixed in a trace amount in the oil phase It is more preferable to use a method (described in JP-A-7-333356) in which the cyclic alcohol is purified by distillation after removing the reaction catalyst with a filter or the like.
[0025]
The present invention is characterized in that the oxidant concentration in the water of the reaction system is lowered. The oxidizing agent referred to in the present invention is a substance that generates a peroxide or hydroperoxide, epoxide, cycloalkenone, or the like, which is a decomposition product of the peroxide, by reaction with a cyclic olefin that is a raw material for hydration reaction. Specific examples include oxygen, air, hydrogen peroxide, ozone, organic peracids, lead tetraacetate, periodic acid, permanganate, nitric acid, nitrous acid, and nitrogen oxides. Examples of the substance having some relationship with the hydration reaction of the cyclic olefin in the region include oxygen, air, and hydrogen peroxide.
By setting the oxidant concentration in water to 0.03 mmol / liter or less, the production of the oxidation reaction product in the reaction system which is the object of the present invention is suppressed.
In order to make the oxidant concentration in water 0.03 mmol / liter or less, it is desirable to keep the oxidant concentration contained in the substance flowing into the reaction system at a low level.
[0026]
Especially, it is necessary to make the oxidant density | concentration in the feed water for replenishing the water reduced by a hydration reaction below 0.03 mmol / liter. Here, “decrease” means that water is reacted and consumed by the hydration reaction, and / or water is dissolved in the oil phase of the reaction solution and extracted out of the reaction system together with the oil. Also, for the purpose of suppressing the oxidant flow in the other route to the reaction system, 1) avoid contact between the cyclic olefin and air as described above, and 2) pressurize the gas phase part of the reactor with an inert gas. 3) When the reactor has an accessory having a sliding part such as a stirrer, use a fluid having a reduced oxidant concentration in accordance with the gist of the present invention as the sealing liquid. It is desirable to use these means in combination.
[0027]
Japanese Patent Application Laid-Open No. 61-234945 discloses a method for regenerating a catalyst subjected to a hydration reaction using an oxidizing agent. JP-A-3-224633 discloses a regeneration method in which an oxidizing agent is brought into contact with a catalyst and then brought into contact with an inorganic alkali and then with an inorganic acid. When ozone or hydrogen peroxide is used as the oxidizing agent in these methods, as described, “Even if the oxidizing agent remains after the treatment, it can be easily removed by thermal decomposition, which is preferable”. It is desirable to use together a method of using a regenerated catalyst after removing the oxidizing agent by thermal decomposition.
[0028]
The most versatile substance of the aforementioned oxidants is oxygen in the air. The oxygen concentration in water of 0.03 mmol / liter corresponds to about 1 mg / liter. As process water used in the process in normal chemical industry, “Boiler Outside Treatment” for boiler water supply (Japan Boiler Association / Boiler Technology Course 6 / Boiler Water Management / Showa 42 issue / p105-142) Used in combination with the equipment described in (1) above, and after undergoing ion exchange treatment. However, this process water usually does not require strict oxygen concentration control like boiler feed water, and this process water storage tank is usually the largest in process water because the gas phase part is usually filled with air. Saturated solubility of oxygen at ambient temperature, ie about 9 mg / liter can be dissolved. Actually, the concentration is usually 5 to 10 mg / liter. In the present invention, this oxygen concentration is reduced to 1 mg / liter or less.
[0029]
As a method of reducing the oxygen concentration, a method of aeration with an inert gas is simple. Specifically, using a packed tower or the like, water before the oxygen reduction treatment is supplied to the upper part of the tower, while an inert gas substantially free of oxygen is supplied from the lower part of the tower, and both are contacted in the tower. Mix. By such an operation, water having a reduced oxygen concentration can be obtained. In the present invention, to make it 1 mg / liter or less, the tower length is set to an appropriate length, the tower diameter is designed to match the amount of treated water, the ratio of treated water and inert gas is adjusted, etc. Is achieved.
[0030]
The measurement of the oxidant concentration in water is performed using a simple known method. Specifically, a suitable method is selected for each target oxidant. For example, in the case of hydrogen peroxide, a certain amount of sample is taken and titrated with a 0.1N potassium permanganate aqueous solution. (Published by Maruzen Co., Ltd./Analytical Analytical Society of Japan / Analytical Chemistry Handbook / Revised Second Edition p27-28) is simple.
The measurement of oxygen concentration in water is usually performed using a commercially available dissolved oxygen meter. A dissolved oxygen meter generally uses a diaphragm electrode, and a polarographic method, a galvanic cell method, etc. are known as means for detecting oxygen.
The effect of reducing the oxygen concentration in the water appears in the form of reduction of cyclic olefin oxidation reaction products in the hydration reactor outlet oil phase. Further, this influence can be indirectly seen in the form of a change in the reaction results with time, that is, a decrease in the concentration of cyclic alcohol over time accompanying a decrease in catalyst activity due to the cyclic olefin oxidation reaction product.
[0031]
The reduction in the catalytic activity due to the cyclic olefin oxidation reaction product becomes more prominent in a used catalyst, that is, a catalyst that has been used for a long time than when a fresh catalyst, that is, a catalyst that has not been used so far, is used. Therefore, it can be said that the effect of reducing the oxygen concentration in water in the present invention is particularly effective for the used catalyst. Although the reason for this difference in the effect is not clear, the desorption phenomenon of intra-lattice metal that occurs in crystalline metallosilicates, that is, as a catalyst accompanying a phase change from a metastable phase to a stable phase under hydrothermal conditions. It is presumed that the adverse effect of the cyclic olefin oxidation reaction product is alleviated in the fresh catalyst due to the relationship with the decrease in activity. The term “long time” as used herein means at least 2000 hours, and the used catalyst is defined as a catalyst that has been subjected to a hydration reaction for a total of 2000 hours or more.
[0032]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples.
[Example 1]
(Water degassing)
As shown in FIG. 1, a deaeration tower 3 was used, and a stainless steel 5/8 inch pole ring 2m was loaded therein as a filler. 100 parts by weight of pure water for boiler water supply having an oxygen concentration of 8 mg / liter was supplied from the supply pipe 1. The liquid load per sectional area in the tower is 60000 kg / m ² -It was hr. On the other hand, nitrogen gas is supplied from the supply pipe 2 to 1 m of supply water. ^Three 0.2Nm for ^Three The deaeration process was implemented. The oxygen concentration in the deaerated water discharged from the discharge pipe 4 was 0.5 mg / liter. In addition, 5 in FIG. 1 shows a gas discharge pipe.
[0033]
[Example 2]
As shown in FIG. 2, a cyclohexene hydration reaction was performed using a continuous flow reactor. That is, 81 g of ZSM-5 catalyst and 219 g of water prepared by the method described in Example 1 of JP-A-1-180835 were charged into a stainless steel reactor 10 with a stirrer having an internal volume of 1 liter, and nitrogen gas was introduced into the system. The pressure was replaced and maintained at 5 Kg / cm 2 G. While stirring at a rotational speed of 850 rpm, the reactor was heated to a reaction temperature of 125 ° C., and then cyclohexene was supplied from the service tank 6 through the supply pipe 8 at a rate of 200 g / hr. Further, from the measurement of the liquid level of the aqueous phase of the separator 12, the same amount of water as the reaction consumed was supplied from the service tank 7 through the supply pipe 9. The oil phase in the reaction mixture taken out from the reactor 10 and sent to the separator 12 through the discharge pipe 11 was taken out from the discharge pipe 13, and the aqueous phase was returned to the reactor 10 through the return pipe 14.
[0034]
At this time, the cyclohexene used contained 2800 ppm of cyclohexane, 7500 ppm of benzene, 55 ppm of toluene and 45 ppm of norcamphane as impurities, and the other components were below the detection limit of gas chromatography, that is, 1 ppm or less. In supplying this cyclohexene, nitrogen gas was sent to the gas phase portion of the service tank 6 to fill the nitrogen gas and avoid contact with oxygen.
As the makeup water from the supply pipe 9, the deaerated water obtained by the deaeration process of Example 1 was supplied via the service tank 7 (while supplying nitrogen gas to the gas phase part). The oxygen concentration in the makeup water was 0.5 mg / liter.
[0035]
As a result of the reaction, the cyclohexanol concentration in the discharged oil was 11.88% by weight 6 hours after the start of cyclohexene supply. The cyclohexanol concentration after 52 hours was 11.49% by weight, and after 98 hours it was 11.11% by weight. Further, after 99 hours, the oxygen concentration in the mother liquor of the aqueous phase partially extracted from the return tube 9 was 0.5 mg / liter. Further, as impurities in the discharged oil after 99 hours, cyclohexane, benzene, toluene and norcamphane in the raw material existed without changing the concentration, and as a reaction by-product, methylcyclopentenes were 800 ppm, methylcyclopentanol. 28 ppm, dicyclohexyl ether was 170 ppm, and other high-boiling components were 100 ppm, but 3-hydroxycyclohexene, 1,2-epoxycyclohexane, and cyclohexenone were not detected (the detection lower limit was 0.1 ppm).
[0036]
[Comparative Example 1]
A hydration reaction was carried out in the same manner as in Example 2 except that water before degassing treatment in Example 1 was used as makeup water from the supply pipe 9. The oxygen concentration in the makeup water was 8 mg / liter. As a result of this reaction, the concentration of cyclohexanol in the discharged oil was 11.87% by weight after 6 hours from the start of the supply of cyclohexene. Further, after 50 hours, the same concentration was 11.38% by weight. Further, after 50 hours, the oxygen concentration in the mother liquor of the aqueous phase partially extracted from the return pipe 14 was 5 mg / liter.
[0037]
Further, as impurities in the discharged oil after 50 hours, cyclohexane, benzene, toluene and norcamphane in the raw material were present without changing the concentration, and as a reaction by-product, 790 ppm of methylcyclopentenes, methylcyclopentanol 26 ppm, dicyclohexyl ether was added to 170 ppm, 3-hydroxycyclohexene was detected at 0.2 ppm, 1,2-epoxycyclohexane was detected at 0.1 ppm, cyclohexenone was detected at 0.1 ppm, and other high-boiling components were present at 100 ppm. It was.
[0038]
[Example 3]
After collecting the catalyst for 2 hours after carrying out the reaction of Example 2 for 2000 hours and removing the oil phase, the same catalyst and water amount as in Example 2 were adjusted to carry out the same reaction as in Example 2. The concentration of cyclohexanol in the discharged oil 6 hours after the start of the reaction was 9.63% by weight, 9.41% by weight after 100 hours, and 9.20% by weight after 194 hours.
[0039]
[Comparative Example 2]
The catalyst was prepared in the same manner as in Example 3, and the reaction was performed without performing nitrogen gas aeration on the feed water as in Comparative Example 1. The concentration of cyclohexanol in the discharged oil 6 hours after the start of the reaction was 9.62% by weight, 9.28% by weight after 80 hours, and 8.87% by weight after 168 hours.
[0040]
【The invention's effect】
By the method of the present invention, generation of cyclohexene oxidation reaction product is suppressed, 1) depletion of the main hydration reaction raw material, and 2) suppression of some energy consumption, such as distillation separation, for removal. Can do.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is an example of a deaeration equipment process flow in carrying out the present invention.
FIG. 2 is an example of a hydration reactor process flow in practicing the present invention. 1 Supply pipe
2 Supply pipe
3 Deaeration tower
4 discharge pipe
5 discharge pipe
6 Service tank
7 Service tank
8 Supply pipe
9 Supply pipe
10 Reactor
11 Discharge pipe
12 Separator
13 Discharge pipe
14 Return pipe

Claims (9)

In the method for producing a cyclic alcohol by using a crystalline metallosilicate represented by the following general formula (1) as a catalyst, in the presence of water, a catalytic hydration reaction of the cyclic olefin represented by the following general formula (2) is performed. A method for producing a cyclic alcohol, wherein the oxidant concentration in the water is 0.03 mmol / liter or less.
qM _{2 / k} O.xSiO ₂ .yAl ₂ O _3. (1-y) Z ₂ O _w (1)
(Wherein M represents at least one k-valent cation, O is oxygen, Si is silicon, Al is aluminum, Z is a metal other than M and aluminum, and boron, gallium, titanium, chromium, iron, zinc Represents at least one w-valent metal selected from phosphorus, vanadium, and copper, and q = 1 ± 0.5, 1 ≦ x ≦ 1000, and 0 ≦ y ≦ 1.
C _n H _2n-2-m R _m (2)
(In the formula, R is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a phenyl group or a cyclohexyl group, n is 5 to 12, and m is an integer of 1 to 4). The method for producing a cyclic alcohol according to claim 1, wherein the oxidizing agent is oxygen. The method for producing a cyclic alcohol according to claim 1 or 2, wherein the concentration of the oxidant in the feed water for replenishing the water reduced by the catalytic hydration reaction is 0.03 mmol / L or less. The method for producing a cyclic alcohol according to claim 3, wherein the supplied water is previously brought into contact with a gas not containing oxygen before being subjected to the reaction. The method for producing a cyclic alcohol according to any one of claims 1 to 4, wherein the catalyst is a catalyst after being subjected to a hydration reaction for a total of 2000 hours or more. 6. The method for producing a cyclic alcohol according to claim 1, wherein the crystalline metallosilicate is a crystalline aluminosilicate. The method for producing a cyclic alcohol according to any one of claims 1 to 6, wherein the cyclic olefin is cyclohexene and the cyclic alcohol is cyclohexanol. The method for producing a cyclic alcohol according to any one of claims 1 to 6, wherein the cyclic olefin is methylcyclopentene and the cyclic alcohol is methylcyclopentanol. The method for producing a cyclic alcohol according to claim 7, wherein cyclohexene, which is a cyclic olefin, is produced by a partial hydrogenation reaction of benzene.

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