JPH09201538A - Regeneration method of cyclic olefin hydration catalyst - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently regenerate a catalyst by a method in which the catalyst is regenerated after the separation into an oil phase and an aqueous phase containing a solid acid catalyst which was used in the hydration of a cyclic olefin at a given temperature or higher. SOLUTION: A cyclic alcohol, an intermediate for various kinds, is prepared by hydrating a cyclic olefin in a liquid phase in the presence of a solid acid catalyst. The catalyst whose activity is deteriorated by repeated cycle of use and regeneration is separated into an oil phase containing the cyclic olefin, the alcohol produced, etc., and an aqueous phase containing the solid acid catalyst at 40 deg.C or higher. Next, the solid acid catalyst recovered from the aqueous phase is burned or treated otherwise. In this way, the catalyst can be regenerated at a high yield, keeping the activity for a long period of time with repeated regeneration.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for regenerating a catalyst. More specifically, the present invention relates to a method for regenerating a solid acid catalyst used when a cyclic olefin is hydrated in a liquid phase to produce a cyclic alcohol useful as various intermediate raw materials.

[0002]

2. Description of the Prior Art In the hydration reaction of olefins in the liquid phase using a solid acid catalyst such as zeolite, the activity of the catalyst gradually decreases as the reaction progresses, mainly because organic substances accumulate on the catalyst. As a method of regenerating such a catalyst with reduced activity, a method of heat-treating at high temperature in the presence of molecular oxygen (Japanese Patent Publication No. 3-2015) and a method of treating with a liquid phase oxidant (Japanese Patent Publication No. 3-2015). Japanese Patent Laid-Open No. 2014 and Japanese Patent Laid-Open No. 3-224633) are known.

[0003]

However, in the conventional regeneration method, the recovery of the activity of the catalyst is insufficient, and particularly when the catalyst is used after repeated use and regeneration for a long period of time, the regeneration is not performed. There is a problem that the activity of the catalyst gradually decreases when it is repeated, which is an insufficient industrial regeneration method.

[0004]

Means for Solving the Problems The present inventor has conducted extensive studies as to a method for regenerating a catalyst whose activity is hardly reduced even after repeated regeneration and use. By adopting a regeneration method having a step of phase-separating an oil phase containing the product alcohol and the like and an aqueous phase containing the catalyst at a temperature of 40 ° C. or higher, regeneration is carried out at a higher regeneration rate than the conventional method. It was found that the catalyst activity can be maintained even when the catalyst is used for a long time while repeating the regeneration, and the present invention has been completed.

That is, according to the present invention, in the hydration reaction of a cyclic olefin in which an aqueous phase and an oil phase containing a cyclic olefin are mixed in the presence of a solid acid catalyst, the solid acid catalyst used for the reaction is regenerated. A phase and an aqueous phase containing a solid acid catalyst are separated at a temperature of 40 ° C. or higher, and then regenerated, which is a method for regenerating a cyclic olefin hydration catalyst.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
The catalyst targeted by the present invention is a solid acid catalyst used in the hydration reaction of cyclic olefins. The solid acid catalyst is an acidic solid substance, and is a strongly acidic ion exchange resin containing a zeolite, a sulfonic acid group, etc., and also contains hydrous niobium oxide, tantalum hydrous oxide, zirconium dioxide, titanium dioxide, aluminum oxide, silicon dioxide, etc. Inorganic oxides or composite oxides thereof, and ion-exchange in which layered compounds such as smectite, kaolinite and vermiculite are treated with one or more metal oxides selected from aluminum, silicon, titanium and zirconium. Examples thereof include type layer compounds, and zeolite is particularly preferable as the solid acid catalyst in the present invention. The form of the solid acid catalyst used is not particularly limited, but it is usually used in the form of powder or granules. Further, alumina, silica, titania or the like may be used as the carrier or binder.

The zeolite catalyst is not particularly limited as long as it can be used as a catalyst, and examples thereof include mordenite, erionite, ferrierite, ZSM-5, ZSM-4 and ZSM-8 announced by Mobil. ZSM
-11, ZSM-12, ZSM-20, ZSM-40,
Aluminosilicates such as ZSM-35 and ZSM-48 type zeolites, and borosilicates and gallosilicates
Examples thereof include zeolites containing different elements such as iron and ferroaluminosilicate. Proton exchange type (H type) is usually used for these zeolites, but a part of them is Na,
It may be exchanged with a cation species selected from alkali elements such as K and Li, alkaline earth elements such as Mg, Ca and Sr, and group 8 elements such as Fe, Co, Ni, Ru and Pd.

In the presence of the above solid acid catalyst, the aqueous phase and the oil phase containing the cyclic olefin can be mixed to carry out the hydration reaction of the cyclic olefin. As the cyclic olefin, cyclopentene, methylcyclopentenes, cyclohexene, methylcyclohexenes, cyclooctene,
Examples thereof include cyclododecene, but cycloalkene having a 5- to 8-membered ring is preferable, and cyclohexene is particularly preferable. Further, other organic substances may coexist as a solvent or an additive in the reaction system. Examples of the organic substance include benzoic acids, carboxylic acids, phenols, salicylic acids, alcohols, fluoroalcohols, ethers, esters, ketones and other oxygen-containing organic compounds, amide compounds. , Nitrogen-containing organic compounds such as nitriles,
Examples thereof include sulfur-containing organic compounds such as thiols and sulfonic acids, halogen-containing organic compounds such as halogenated carbons, aliphatic hydrocarbons and aromatic hydrocarbons.

In the hydration reaction, water and a cyclic olefin are mixed and reacted in the presence of a solid acid catalyst. If the mixing is weakened during the reaction or the reaction is stopped, the water phase and the oil phase are separated. The volume ratio of the oil phase to the water phase is usually 0.01 to 1
It is 0, preferably 0.1 to 1. When the amount of the cyclic olefin or water as the raw material is excessively large as compared with one of them, the separation of the aqueous phase and the oil phase is poor, and the reaction rate also decreases, which is not preferable. The weight ratio of the catalyst to the cyclic olefin is usually 0.01 to 20, preferably 0.05.
~ 5. When the amount of the catalyst is too small, the reaction rate becomes slow and the reactor becomes large, and when the amount of the catalyst is too large, the catalyst cost becomes large, which is not preferable.

When the mixing is stopped during the hydration reaction and the water phase and the oil phase are separated, the water phase mainly contains the solid acid catalyst, and the oil phase contains the starting cyclic olefin and the formed cyclic olefin. Contains alcohol. The hydration reaction is carried out by mixing the water phase and the oil phase by stirring or the like, thereby suspending the oil phase, for example, the oil phase dispersed in a droplet state in the continuous water phase. The reaction system may be either a batch system or a continuous system. As the hydration reaction condition, the reaction temperature is usually 50 to 300, although the optimum temperature range varies depending on the starting cyclic olefin used.
℃, preferably 70 ~ 200 ℃, more preferably 80 ~
160 ° C. The reaction pressure is not particularly limited, but a pressure capable of keeping cycloalkene and water in a liquid phase is preferable, and is usually 5 MPa or less, preferably 0.2 to 2 MPa.
The reaction time or residence time is usually 1 minute to 10 hours, preferably 5 minutes to 5 hours. The hydration reaction system is preferably maintained under an atmosphere of an inert gas such as nitrogen, helium, hydrogen, argon, or carbon dioxide. In this case, it is preferable that the content of oxygen in the inert gas is small, and the content of oxygen is usually 100 ppm or less, preferably 20 ppm or less.

As a method of recovering the desired cyclic alcohol produced from the hydration reaction mixture, it is first necessary to separate the reaction mixture into an aqueous phase and an oil phase. The aqueous phase containing the catalyst is
After separation, it can be recycled to the reactor for reuse. Further, the cyclic alcohol can be easily purified and recovered from the separated oil phase by a known method such as distillation.
The residual liquid containing the starting olefin after separating the cyclic alcohol can be reused as a starting material for the hydration reaction.

In the hydration reaction of the cyclic olefin as described above, there is a problem that the activity of the solid acid catalyst rapidly decreases with the progress of the reaction. Therefore, for example, in a continuous reaction, it is necessary to extract at least a part of the catalyst in the aqueous phase separated from the reaction mixture and perform a catalyst regeneration treatment by the method as in the above-mentioned conventional technique. The present invention separates an aqueous phase from the above hydration reaction mixture of cyclic olefins, recovers the solid acid catalyst from the aqueous phase, and regenerates the oil phase and the solid acid catalyst from the hydration reaction mixture. Is included at a temperature of 40 ° C. or higher.

As a method for separating the oil phase and the aqueous phase from the hydration reaction mixture at a temperature of 40 ° C. or higher, a part or all of the reaction mixture is continuously or intermittently withdrawn from the hydration reactor, A method of introducing the oil into an external oil / water separation tank and allowing the oil / water separation tank to stand still while keeping the temperature at 40 ° C. or higher to separate the water phase and the oil phase is preferable. Further, in the case of a reactor in which an oil / water separation weir is provided in the reactor, a method of extracting a water phase portion in the oil / water separation weir by keeping the temperature in the oil / water separation weir in the reactor at 40 ° C. or higher Is also possible. In this case, since the oil phase is easily mixed in the water phase, if necessary, the oil phase may be separated again in an oil / water separation tank outside the reactor where the temperature is kept at 40 ° C or higher.

The catalyst is recovered from the aqueous phase separated by the above method by filtration or the like. The recovered catalyst may be washed with water or dried, if necessary, and then subjected to a regeneration treatment. The temperature for separating the oil phase / water phase is 40 ° C or higher,
It is preferably 75 ° C or higher, particularly preferably 95 ° C or higher. The upper limit of temperature is usually 200 ° C. or lower, preferably 150.
The separation is carried out at a temperature of not higher than 0 ° C and usually lower than the hydration reaction. If the temperature is unnecessarily low, the catalyst activity will be remarkably lowered when the regeneration is repeated, and if the temperature is too high, the selectivity as a catalyst will be lowered and side reactions will easily occur, which is not preferable.

The reason why the separation temperature of the oil phase and the water phase, which is the feature of the present invention, is important in the catalyst regeneration is considered as follows. In the hydration reaction of the cyclic olefin, the amount of each component forming the oil phase is in an equilibrium relationship among the oil phase, the water phase and the three phases on the catalyst. And, generally, the higher the temperature, the more organic components that form these oil phases,
It has a greater tendency to partition into the oil phase than on the catalyst. Therefore, even in the same reaction mixture, the amount of organic substances attached to the catalyst in the aqueous phase after separating the oil phase differs depending on the temperature at which the oil phase is separated.

Further, when the oil phase and the water phase are separated, the organic matter once attached on the catalyst surface is hardly re-extracted into the oil phase because the mixing of the reaction mixture is weakened or stopped. Imagine the situation. Therefore, such an organic substance exists at a high concentration on the catalyst, is easily subjected to a reaction such as dimerization or oligomerization, and is irreversibly adsorbed, that is, is easily accumulated on the catalyst. Further, such an organic substance is difficult to be removed by a commonly known regeneration method, for example, a method of treating at high temperature in the presence of molecular oxygen or a method of causing an oxidizing agent such as hydrogen peroxide to act in a liquid phase. As a result, for example, in the high temperature treatment in the presence of molecular oxygen, it is not completely burned or decomposed by heat and remains as so-called coke on the catalyst, and in the hydrogen peroxide treatment in the liquid phase, it is sufficiently oxidized. It is not decomposed and strongly adsorbs as a carbonyl-type intermediate on the catalyst. Therefore, when the catalyst is repeatedly used and regenerated, the above-mentioned organic substances which are not completely removed gradually accumulate on the catalyst, which lowers the activity of the catalyst.

On the other hand, in the method of the present invention, when the oil phase and the aqueous phase are separated, by keeping the temperature high, the adhesion of organic substances on the catalyst is significantly suppressed, and the organic substances on the catalyst are significantly suppressed. Easy to remove. Therefore, even if the regeneration is repeated, the amount of organic substances accumulated on the catalyst can be remarkably suppressed, and it is presumed that the activity of the catalyst does not decrease. The method of regenerating the catalyst separated and recovered by the method of the present invention is not particularly limited, but the following two are exemplified as preferable methods. After the regeneration treatment, the catalyst is slurried into water and again used in the hydration reactor.

The first preferred method for regenerating the solid acid catalyst is as follows:
In this method, the solid acid catalyst recovered from the separated aqueous phase is calcined. The heating device may be of any type such as a general tubular furnace or a muffle furnace, and is preferably a device capable of performing contact operation with gas in a fixed bed or fluidized bed form by a normal gas flow method. The solid acid catalyst is calcined at a contact temperature of usually 200 to 600 ° C. In this case, it is desirable to carry out the calcination while bringing the solid acid catalyst and the gas into contact with each other under gas flow, and the gas flow rate is usually 0.25 to 50 hr ^{−1 in} weight hourly space velocity (WHSV) with respect to the solid acid catalyst, and the contact time is It is usually 1 minute to 100 hours, preferably 5 minutes to 50 hours. As the circulating gas, a gas containing molecular oxygen,
Nitrogen, helium, argon and the like are used, and it is desirable that water in the gas is usually removed. The contact treatment may be either a low temperature treatment or a temperature varying treatment, but the temperature varying treatment is preferred. It is preferable that the low-temperature treatment and the high-temperature treatment are separately performed, and the molecular oxygen concentration in the low-temperature treatment atmosphere is lower than that in the high-temperature treatment. Further, the low temperature treatment may be performed under the condition that molecular oxygen is not contained, for example, in a nitrogen or helium atmosphere.

In a preferred embodiment of the calcination method, the solid acid catalyst is first subjected to contact treatment with nitrogen at 100 to 450 ° C.,
A method of contact treatment with a gas containing molecular oxygen at 400 to 600 ° C. is exemplified. In this case, the contact treatment temperature with nitrogen is preferably lower than the contact treatment temperature with molecular oxygen. After the catalyst is brought into contact with nitrogen to reduce the organic matter on the catalyst in advance, the organic matter adhering to the catalyst can be removed more efficiently by treating with the molecular oxygen-containing gas at a higher temperature.

The catalyst subjected to the above-mentioned calcination can be reused as it is for the hydration reaction, but it may be treated with an aqueous solution of an alkaline inorganic salt containing sodium hydroxide or the like. By the contact treatment with the alkaline aqueous solution, it is possible to restore a slight structural change of the solid acid catalyst slightly generated by the calcination treatment, and it is possible to further enhance the regeneration effect. Since the catalyst treated with the alkaline aqueous solution is usually ion-exchanged with a cation species derived from the alkaline aqueous solution, it may be further subjected to an ion-exchange treatment with a desired ionic species, if necessary.

Next, the second preferable method for regenerating the solid acid catalyst is a method in which the solid acid catalyst recovered from the separated aqueous phase is treated with an oxidant in the liquid phase. Specifically, the zeolite catalyst extracted from the hydration step and the oxidizing agent are treated in the same liquid phase. Examples of the oxidizing agent include hydrogen peroxide, ozone, organic peracid, nitric acid, nitrous acid, and the like.
Hydrogen peroxide and ozone are preferred. The amount of the oxidant used varies depending on the state of decrease in catalyst activity, but is usually 0.01 to 20 in terms of the weight ratio of the oxidant to the catalyst. The concentration of the oxidizing agent is usually 0.001 to 0.001 with respect to the liquid phase.
It is 70% by weight, preferably 0.1-40% by weight. The treatment conditions are usually a contact treatment in a polar solvent solution such as water having a temperature of 20 to 120 ° C. and a pH of 13 or less for about 15 minutes to 50 hours. After the oxidant treatment, the catalyst may be washed with water or dried if necessary.

[0022]

EXAMPLES Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples as long as the gist of the present invention is not exceeded. Example 1 (Continuous flow hydration reaction of cyclohexene) The hydration reaction of cyclohexene was carried out using a continuous flow reactor as shown in FIG. That is, 100 g of H-type gallium silicate (SiO ₂ / Ga ₂ O ₃ molecular ratio = 50/1) and 250 g of water were added as a hydration catalyst to a stainless steel autoclave reactor 3 with an internal volume of 2000 ml equipped with a stirrer. After charging, the system was replaced with nitrogen gas. After stirring the reactor at a rotation speed of 500 rpm to raise the temperature inside the reactor 3 to a reaction temperature of 120 ° C., cyclohexene was supplied from the supply pipe 1 at a rate of 120 g / hr. The reaction liquid is separated into an oil phase and an aqueous phase containing a catalyst in an oil-water separation weir 4 having an internal volume of 30 ml installed inside the reactor, and then only the oil phase is flown out from the overflow pipe 5. In addition, the water and the overwater consumed in the hydration reaction are supplied from the supply pipe 2.
The amount of water in the reactor 3 was kept constant by supplying the total amount of water flowing out from the flow tube 5 as a dissolved component to the oil phase. The cyclohexanol concentration in the spilled oil phase was 12.5% by weight 5 hours after the start of feeding the starting material cyclohexene. Further, the cyclohexanol concentration in the spilled oil phase after 200 hours was 9.8% by weight.

(Oil phase / water phase separation of reaction mixture) After 200 hours of the above continuous flow reaction, the supply of cyclohexene and water to the reactor was stopped. While keeping the reaction mixture at 120 ° C., the reaction mixture was taken out from the reaction mixture taking-out port 6 provided at the bottom of the reactor, led to an oil / water separation tank (not shown) separately provided outside the reactor, and the internal liquid temperature was made at the oil / water separation tank. While maintaining 120 ° C., an oil phase and an aqueous phase containing a catalyst were separated. At this time, no catalyst was found in the separated oil phase.

(Catalyst Regeneration-Gas Phase Oxidation Treatment) The catalyst in the separated aqueous phase was filtered, washed with water and dried at 110 ° C. The catalyst after drying was filled in a quartz glass tube to obtain a purity of 9
Firing was performed at 300 ° C. for 1 hour while flowing 9.999% nitrogen gas at a flow rate of 90 NL / hr at normal pressure. Then, the circulating gas was changed from nitrogen to dry air, and firing was performed at 540 ° C. for 2 hours. (First-time continuous flow reaction with regenerated catalyst) A continuous hydration reaction was performed under the same reaction conditions as in the above (continuous flow hydration reaction of cyclohexene) except that a regenerated catalyst was used. Table 1 shows the cyclohexanol concentration in the effluent oil phase after 5 hours of continuous flow reaction using the regenerated catalyst. The activity was completely restored.

(Repetition of Reaction and Regeneration Operation) The above-mentioned first-time regeneration catalyst was reacted for 200 hours under the same reaction conditions as the above-mentioned (continuous flowing hydration reaction of cyclohexene). After the reaction, the oil phase is separated by the same method as the above (oil phase / aqueous phase separation of reaction mixture), and then the catalyst in the aqueous phase is filtered by the same method as the above (catalyst regeneration-gas phase oxidation treatment). It was regenerated after being washed with water and dried. This continuous flow hydration reaction-regeneration operation was repeated 9 times in total. In all cases, no catalyst was found in the separated oil phase. (Reaction, continuous circulation reaction by repeated regeneration catalyst) Using the above-mentioned continuous circulation hydration reaction-regeneration repeated catalyst (catalyst that has been regenerated for the 10th time counting from the new catalyst), the above (continuous circulation by regenerated catalyst) Hydration reaction was carried out under the same conditions as (Reaction). Table 1 shows the cyclohexanol concentration in the effluent oil phase after 5 hours of continuous flow.

Example 2 Example 2 was repeated except that the internal liquid temperature in the oil-water separation tank in Example 1 was changed to 80 ° C. In all cases, no catalyst was found in the separated oil phase.
Table 1 shows the cyclohexanol concentration in the effluent oil phase at 5 hours after the continuous flow reaction using the 1st regeneration catalyst and the 10th regeneration catalyst.

Comparative Example 1 The procedure of Example 1 was repeated, except that the internal liquid temperature in the oil / water separation tank in Example 1 was changed to 30 ° C. At this time, a trace amount of catalyst was found to be mixed in the separated oil phase. Table 5 shows the cyclohexanol concentration in the effluent oil phase at 5 hours after the continuous flow reaction using the 1st regeneration catalyst and the 10th regeneration catalyst.
It is shown in FIG.

[Table 1]

Example 3 The procedure of Example 1 was repeated except that the (catalyst regeneration-gas phase oxidation treatment) in Example 1 was changed to the following (catalyst regeneration-liquid phase oxidant treatment). First regeneration catalyst and 1
Table 2 shows the cyclohexanol concentration in the effluent oil phase at 5 hours after the continuous flow reaction using the 0th regeneration catalyst. (Catalyst Regeneration-Liquid Phase Oxidation Treatment) After the catalyst in the aqueous phase was filtered and washed with water, an internal volume of 1000 ml of glass autoclave
After the reaction, the recovered catalyst and 180 ml of water were charged, and the temperature was raised to 70 ° C. with stirring. Then, add 350 ml of 30% hydrogen peroxide aqueous solution little by little, and then at 70 ° C for 5 hours.
and stirred. The treated catalyst was filtered, washed with water, and dried.

Examples 4 and 5 Example 3 was repeated except that the internal liquid temperature in the oil / water separation tank in Example 3 was changed as shown in Table 2. Table 2 shows the cyclohexanol concentration in the effluent oil phase at 5 hours after the continuous flow reaction using the 1st regeneration catalyst and the 10th regeneration catalyst.

Comparative Example 2 Example 3 was repeated except that the internal liquid temperature in the oil / water separation tank in Example 3 was changed to 30 ° C. Table 2 shows the cyclohexanol concentration in the effluent oil phase at 5 hours after the continuous flow reaction using the 1st regeneration catalyst and the 10th regeneration catalyst.

[Table 2]

[0031]

According to the present invention, the catalyst used in the hydration reaction of cyclic olefin can be efficiently regenerated. In particular, it is suitable when the regeneration and use of the catalyst are repeated many times to carry out the hydration reaction of the cyclic olefin for a long period of time.

[Brief description of drawings]

FIG. 1 shows a schematic diagram of a continuous flow reactor used in Examples.

[Explanation of symbols]

 1: Cyclohexene supply pipe 2: Water supply pipe 3: Reactor 4: Oil-water separation weir 5: Overflow pipe 6: Reaction mixture outlet

Claims (4)

[Claims] 1. In the hydration reaction of a cyclic olefin in which an aqueous phase and an oil phase containing a cyclic olefin are mixed in the presence of a solid acid catalyst, an oil phase and a solid are used to regenerate the solid acid catalyst used in the reaction. A method for regenerating a cyclic olefin hydration catalyst, characterized in that an aqueous phase containing an acid catalyst is separated at a temperature of 40 ° C. or higher and then regenerated. 2. The method according to claim 1, wherein the solid acid catalyst recovered from the separated aqueous phase is calcined. 3. The method according to claim 1, wherein the solid acid catalyst recovered from the separated aqueous phase is treated with an oxidizing agent in the liquid phase. 4. The method according to claim 1, wherein an oil phase and an aqueous phase containing a solid acid catalyst are separated in an oil / water separation tank outside the reactor.