JPH0912493A - Hydration reaction of olefin - Google Patents

Abstract

PURPOSE: To completely recover a catalytic activity of zeolite and highly keep a catalytic activity by reactivating the zeolite lowered in its catalytic activity, pulled out from a reaction zone using a specific method after carrying out hydration reaction of an olefin. CONSTITUTION: After carrying out hydration reaction of an olefin using zeolite as a catalyst, the zeolite taken out of a reaction zone is subjected to hydrothermal synthesis in an alkaline solution so that 100% of the crystal structure of the zeolite is lost by dissolution or formation of amorphous structure. Then, cation species of the zeolite produced by the hydrothermal reaction are converted into desired cation species to re-use it for the hydration reaction. It is preferable that a part of the zeolite taken out of the reaction zone is reactivated by the method heating the part thereof in a gas phase and removing organic substances adhering thereto and supplied to the reaction system and that the residual part thereof is reactivated by the hydrothermal synthetic treatment using the above method. It is also preferable that the hydrothermal synthesis is carried out at 90 to 270 deg.C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an alcohol, which is important as a chemical raw material, by hydrating an olefin. In particular, the present invention relates to an improvement in the method for carrying out the hydration reaction using zeolite as a catalyst.

[0002]

2. Description of the Related Art In the hydration reaction of olefins using zeolite as a catalyst, the activity of the catalyst gradually decreases with the progress of the reaction, mainly because organic substances accumulate on the catalyst. Such a catalyst whose activity has been lowered is used again for the hydration reaction of olefins after undergoing a regeneration step by a vapor phase heat treatment or a liquid phase treatment. As a regeneration method, for example, a method of contacting with a gas containing molecular oxygen at high temperature (Japanese Patent Publication No. 3-2)
015), a method of contacting with an acid, an alkali or an oxidizing agent in a liquid phase (Japanese Patent Publication No. 3-2014, JP-A-3-2014).
No. 224632, JP-A-3-224633)
Etc. are known.

[0003]

However, these conventional known regeneration methods have problems that the regeneration rate is not sufficient or that the catalyst activity gradually decreases when regeneration-use is repeated. Further, a method for reactivating a catalyst whose activity has been lowered by such repeated regeneration-use has not been known so far.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies on a method of reactivating a zeolite having a lowered catalytic activity by using it in a hydration reaction of an olefin. It is possible to carry out the hydration reaction while maintaining the high activity of the catalyst by treating it in an aqueous solution under hydrothermal synthesis conditions, further converting the cation species into desired cation species, and then subjecting them to the hydration reaction. The present invention has been completed and the present invention has been completed.

According to the studies made by the present inventors, it is considered that the crystal structure itself of the zeolite with reduced activity has some change. This change in crystal structure may also be caused by reactivation itself by a conventional method. Therefore, in order to recover the catalytic activity of zeolite, it is considered that it is not enough to simply remove the accumulated organic matter, but it is necessary to repair the crystal structure itself. In the present invention, the zeolite with reduced activity is treated under hydrothermal synthesis conditions, that is, the conditions under which the zeolite is produced, so that the crystal structure is restored.

The present invention will be described in detail. In the present invention, various zeolites having catalytic activity for the hydration reaction can be used. For example, crystalline aluminosilicates such as mordenite, erionite, ferrierite, and ZSM-based zeolites such as ZSM-5 and ZSM-11 are used. In addition, heteroelement-containing zeolites such as metallosilicates such as borosilicate, gallosilicate, and ferrosilicate, aluminometallosilicates such as boroaluminosilicate, galloaluminosilicate, and ferroaluminosilicate are also used. These zeolites are usually used as a proton exchange type (H type), but some or all of the protons are further alkaline earth elements such as Mg, Ca and Sr, rare earth elements such as La and Ce, Fe and C.
It may be exchanged with at least one cation species selected from Group VIII elements such as o, Ni, Ru, Pd, Pt. Also, if desired, Ti, Zr, Hf, Cr, M
It is also possible to use a zeolite containing o, W, Th, Cu, Ag or the like. The zeolite may be in any form, for example, powdery or granular form can be used. Also, a molded product using alumina, silica, titania, a clay compound or the like as a binder or carrier can be used.

The olefin used for the hydration reaction is an olefin having a linear or branched structure having 2 to 12 carbon atoms such as propylene, butene, octene, or the number of carbon atoms such as cyclopentene, methylcyclopentene, cyclohexene and cyclooctene. 5-12 cyclic olefins are mentioned. The present invention is particularly effective for hydration of cyclic olefin.

In the present invention, the hydration reaction is carried out according to a conventional method. For example, water and olefin can be placed in a reactor, and the catalyst zeolite can be suspended in the reactor, and the reaction can be carried out in a batch system while stirring. Further, a suspension of zeolite is stored in a reactor, water and olefin are continuously supplied to the suspension, and at the same time, reaction is carried out in a continuous system in which a reaction liquid containing produced alcohol, water and unreacted olefin is withdrawn. You can also In this case, the reaction liquid may be separated into oil and water to extract only the oil phase. In the case of the continuous system, a part of the catalyst is extracted together with the reaction solution, the extracted catalyst is subjected to a regeneration treatment according to the method of the present invention to be reactivated, and then returned to the reactor to remove the catalyst in the reactor. It is preferred to maintain activity at a constant level at all times. The hydration reaction is usually performed at 50 to 200 ° C. For cyclic olefins such as cyclohexene, 100-200 ° C is suitable. The reaction is usually carried out under autogenous pressure, but if desired, a gas such as nitrogen, hydrogen, helium, argon or carbon dioxide may be present in the gas phase. In addition, Japanese Unexamined Patent Publication No.
An aliphatic hydrocarbon, an aromatic hydrocarbon, an oxygen-containing organic compound, a sulfur-containing organic compound, a halogen-containing organic compound, etc. as described in 8-194828 may be present in the reaction system.

In the present invention, the activity-reduced catalyst extracted from the olefin hydration reaction step is treated and reactivated in an alkaline aqueous solution under hydrothermal synthesis conditions. Usually, a part of the withdrawn catalyst is treated under the hydrothermal synthesis conditions according to the method of the present invention, and the rest is reactivated by a conventional method, for example, a method of contacting with a molecular oxygen-containing gas in the gas phase at high temperature 3-2015), a method of contacting with an acid, an alkali, or an oxidizing agent in a liquid phase (Japanese Patent Publication No. 3-2014, JP-A-3-224632, JP-A-3-224633) and the like. Is advantageous. For example, the regeneration treatment of contacting with the molecular oxygen-containing gas at high temperature is most easily 0.01 to 90 mol%, preferably 1 to 30.
A mixed gas containing mol% of oxygen and the balance being an inert gas such as nitrogen, helium, or argon, and an extraction catalyst were mixed with 200
The contact may be performed at ˜600 ° C. for 1 to 100 hours, preferably 2 to 20 hours. These treatments are usually carried out at normal pressure, but if desired, they can be carried out under pressure or under reduced pressure.

The treatment under the hydrothermal synthesis condition according to the method of the present invention is usually performed on the catalyst itself withdrawn from the reactor, but if desired, the catalyst withdrawn is subjected to the regeneration treatment by the above-mentioned conventional method. You may do it. In this regeneration method, the extraction catalyst is put in an alkaline aqueous solution,
Hold at 270 ° C. under conditions where catalytic zeolite is formed. As the alkaline aqueous solution, an aqueous solution of an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide is usually used, but an alkali metal carbonate or bicarbonate, an alkaline earth metal hydroxide, etc. coexist. May be. That is, the composition may be any suitable as a liquid phase when producing zeolite by hydrothermal synthesis. Further, the ratio of the alkali aqueous solution to the extraction catalyst and the ratio of the alkali in the aqueous solution may be those suitable for producing zeolite by hydrothermal synthesis. The amount of the alkaline aqueous solution per 1 kg of the extracted catalyst is usually 3 to 60 kg, preferably 5 to 30 kg.
Also, the amount of alkali per 1 kg of extracted catalyst is 0.15 to
150 g equivalent, preferably 0.5 to 50 g equivalent.

In the regeneration method by hydrothermal synthesis of the present invention, the extraction catalyst reacts with the alkali in the alkaline aqueous solution in the regeneration process, and the zeolite is partially or completely dissolved or changed into an amorphous state. Go through. In the present invention, the conditions are set such that 50% or more of the crystal structure of the zeolite of the extraction catalyst disappears due to dissolution or amorphization. It is preferable to set the conditions for hydrothermal synthesis so that 80% or more, particularly substantially 100%, of the crystal structure of zeolite disappears due to dissolution or amorphization. The disappearance of the crystal structure due to dissolution or amorphization of zeolite depends on the concentration and temperature of the alkaline aqueous solution, and the higher the concentration of the alkaline aqueous solution and the higher the treatment temperature, the faster the progress.

Regeneration by hydrothermal synthesis of the present invention is most simply carried out by adding a catalyst to an aqueous alkaline solution and maintaining it under predetermined hydrothermal reaction conditions. In addition, a catalyst is added to an aqueous alkaline solution to remove a part or all of the crystal structure of zeolite, and then an acid or an alkali is added as necessary to adjust the pH, and then the mixture is kept under hydrothermal synthesis conditions. You may do it. The suitable pH in this case is 9-14.

At the time of hydrothermal synthesis, it is preferable to add a template (crystallizing agent) to an alkaline aqueous solution in order to promote the regeneration of zeolite having a desired crystal structure. As a template, a quaternary alkylammonium compound such as tetrapropylammonium salt, a primary alkylamine, a secondary alkylamine, an alkylamine such as a tertiary alkylamine, a diamine, an aminoalcohol, an alcohol, an ether, and an amide. , Alkyl ureas,
Alkyl thioureas and cyano alkanes are used. These are all suitable M for the hydration reaction according to the present invention.
This gives a FI structure zeolite. The fourth of these
Grade alkyl ammonium salts are preferred. In addition, you may use a template in combination of 2 or more types. The amount of the template is 0.1 to 10 per 1 kg of zeolite as the catalyst to be extracted.
It is 0 mol, preferably 0.2 to 50 mol.

The temperature of hydrothermal synthesis is usually 90 to 270 ° C,
It is preferably 100 to 210 ° C. Hydrothermal synthesis is preferably carried out with stirring. The time required for hydrothermal synthesis is usually 6 hours or longer, preferably 10 to 200 hours. The hydrothermal synthesis pressure is usually a spontaneous pressure, but an inert gas may be used to increase the pressure, if desired. This hydrothermal synthesis produces substantially the same amount of zeolite as the extraction catalyst, violite. Zeolite produced by hydrothermal synthesis is
It contains a cationic species derived from an alkaline aqueous solution. As described above, the zeolite used for hydration of olefins is usually a proton exchange type (H type) or a type in which a part or all of this proton is exchanged with other cation species.
Zeolites obtained by the above-mentioned hydrothermal synthesis must also be converted to these types before being used as a catalyst in the reaction.

The cation species can be exchanged by washing the zeolite obtained by hydrothermal synthesis with water and then bringing it into contact with an aqueous solution containing the cation species to be introduced. When a template is used for hydrothermal synthesis, it is desirable to remove it beforehand by firing or the like. The cation species can be exchanged according to a known method. For example, in the case of the proton type, an acid aqueous solution such as hydrochloric acid, nitric acid or sulfuric acid is used.
Alternatively, a method of decomposing ammonia by heating after using an ammonium ion type may be used.
When the cation species is a metal ion, a hydrochloride, nitrate, sulfate or the like of the cation may be used.

The concentration of cations in the aqueous solution used for cation exchange is usually 0.001 to 10 mol / l, preferably 0.01 to 8 mol / l. The equivalent ratio of cation to the exchange capacity of zeolite is usually 100 or less. Cation exchange is usually performed at 0-100 ° C under normal pressure. Usually, the zeolite may be added to an aqueous solution containing a cation species to be introduced and allowed to stand or stirred to perform ion exchange. After the cation exchange is completed, it is washed with water, dried, and used again for the olefin hydration reaction. In the case of desorbing ammonia from the ammonium ion type to form the proton type, the simplest method is to dry the ammonium ion type zeolite and then to remove 200 to 200
Ammonia may be desorbed by heating at 600 ° C.

[0017]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof. Example 1 Cyclohexene Continuous Flow Hydration Reaction A cyclohexene hydration reaction was carried out using a continuous flow reactor as shown in FIG. That is, the internal volume 2000
In a stainless steel autoclave 3 with a stirring device of ml,
H-type gallosilicate as a hydration catalyst (MFI type, manufactured by NE Chemcat, SiO ₂ / Ga ₂ O ₃ molar ratio = 45 /
1) 100 g and 250 g of water were charged and the system was replaced with nitrogen gas. The reactor 3 was heated to 120 ° C. while stirring at a rotation speed of 500 rpm, and then cyclohexene (reagent: Aldrich) was supplied from the supply pipe 1 at a rate of 120 g / h. The reaction liquid is 30ml inside volume set inside the reactor
Is separated into an oil phase and a catalyst slurry phase in the liquid-liquid separator 4 of
Only the oil phase flows out from the overflow pipe 5. Further, from the supply pipe 2, the total amount of water consumed in the hydration reaction and water flowing out after being dissolved in the oil phase was supplied to keep the amount of water in the autoclave 3 constant. The cyclohexanol concentration in the spilled oil 5 hours after the start of the cyclohexene supply was 11.1% by weight. The concentration of cyclohexanol in the spilled oil after the lapse of 300 hours was 4.3% by weight.

Regeneration of catalyst by vapor-phase heat treatment After the above continuous flow hydration reaction was carried out for 300 hours, the catalyst was taken out, washed with water and dried. This catalyst was filled in a quartz glass reaction tube, and a mixed gas of 4 mol% oxygen and the balance nitrogen was flowed at a normal pressure of 150 Nl / h for 50
The catalyst was regenerated by heating at 0 ° C for 5 hours. The catalyst after regeneration was pure white, and no carbon component was found even when analyzed by an elemental analyzer for organic substances.

The continuous flow hydration reaction was repeated under exactly the same reaction conditions and regeneration conditions while repeating the regeneration every 300 hours. The cyclohexanol concentration in the effluent oil at the fifth hour of the continuous flow hydration reaction using the catalyst after the tenth regeneration was 6.0% by weight. Further, the catalyst after each regeneration was pure white, and no carbon component remained even when analyzed by an elemental analyzer for organic substances.

Reactivation of the catalyst which has been repeatedly regenerated by vapor-phase heat treatment. After performing the continuous flow hydration reaction for 300 hours using the catalyst after the 10th regeneration described above, the catalyst is regenerated in the same manner as above. Was done. This regenerated catalyst was prepared by dissolving 8 g of sodium hydroxide in 1400 g of water and adding 22.5% by weight thereto.
Tetrapropyl ammonium hydroxide aqueous solution 145
g was added to the added solution. This was placed in an autoclave and subjected to a hydrothermal synthesis treatment of heating at 180 ° C. for 40 hours under a spontaneous pressure while stirring. Inferred from the findings of other experiments, it is considered that during this treatment process, the crystal structure of the zeolite was almost completely destroyed, and the zeolite once became an amorphous gel state, and then the zeolite was crystallized again from this state. . Zeolite is filtered and washed with water, then 120 ℃
For 12 hours. Then, it was baked in air at 550 ° C. for 6 hours to remove organic substances. 10 times the dry weight of 1N
-After stirring in an aqueous solution of ammonium nitrate for 2 hours while maintaining the temperature at 100 ° C, the zeolite was filtered and washed with water. This treatment with the ammonium nitrate aqueous solution was repeated twice. After the zeolite is dried, it is filled in a quartz glass tube, and air is flowed at a flow rate of 150 Nl / h at atmospheric pressure at 500 ° C.
For 2 hours.

Continuous flow hydration reaction with reactivating catalyst A continuous flow hydration reaction was carried out under the same reaction conditions as before except that the thus regenerated zeolite [H type] was used as a catalyst. The cyclohexanol concentration in the effluent oil 5 hours after the continuous flow hydration reaction was 11.3% by weight.

Comparative Example 1 In the same manner as in Example 1, continuous flow hydration reaction and regeneration by gas phase heat treatment were repeated. The catalyst after the 10th regeneration is
It was added to 0.3N-sodium hydroxide aqueous solution in an amount 10 times the dry weight of the catalyst, and stirred for 1 hour while maintaining the temperature at 80 ° C. In this treatment, since the treatment conditions were mild, no substantial change was observed in the crystal structure. After filtering the catalyst and washing with water,
The mixture was stirred in an aqueous 1N-ammonium nitrate solution in an amount 10 times the dry weight of the catalyst for 1 hour while maintaining the temperature at 100 ° C. to perform ion exchange into ammonium type. The catalyst was filtered, washed with water, dried, and then filled in a quartz glass tube, and air was blown to 150 Nl / h.
While flowing at a normal pressure with a flow rate of
Type zeolite. A continuous flow hydration reaction was carried out under the same reaction conditions as before except that this catalyst was used. The cyclohexanol concentration in the effluent oil after 5 hours from the continuous flow hydration reaction was 9.2% by weight.

[0023]

EFFECTS OF THE INVENTION According to the present invention, it is possible to almost completely regenerate a catalyst whose catalytic activity has been lowered by repeating regeneration by the conventional technique.

[Brief description of the drawings]

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

[Explanation of symbols]

 1 cyclohexene supply pipe 2 water supply pipe 3 autoclave 4 liquid-liquid separator 5 overflow pipe

Claims (6)

[Claims] 1. In an olefin hydration reaction using a zeolite as a catalyst, the zeolite with reduced activity extracted from the reaction zone is treated under hydrothermal synthesis conditions in an alkaline aqueous solution, and then a cation species of the zeolite is desired. The method is characterized in that the cation is converted to the cation species described above and is again subjected to a hydration reaction. 2. In the hydration reaction of olefin using zeolite as a catalyst, the activity-reduced zeolite is extracted from the reaction zone, and a part of it is heated in the gas phase for reactivation to remove adhering organic matter. Then, the remainder is treated in an aqueous alkali solution under hydrothermal synthesis conditions, and then the cation species of the zeolite are converted into the desired cation species and then reactivated and fed to the reaction zone. . 3. The zeolite extracted from the reaction zone,
The method according to claim 1 or 2, wherein the method is performed under hydrothermal synthesis conditions after heating in a gas phase to remove attached organic substances. 4. The process under hydrothermal synthesis conditions is to regenerate a zeolite having the same crystal structure as the original zeolite through a process in which 50% or more of the crystal structure of the zeolite disappears. The method according to any one of claims 1 to 3. 5. The method according to claim 1, wherein the temperature of hydrothermal synthesis is 90 to 270 ° C. 6. The method according to claim 1, wherein the alkaline aqueous solution contains a template.