JPH0930999A - Hydration of olefin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To carry out hydration reaction of an olefin while remarkably suppressing the lowering of the catalytic activity. SOLUTION: This olefin hydration process comprises a hydration step to hydrate an olefin in the presence of a zeolite catalyst, a removing step to remove the organic material attached to the zeolite catalyst used in the hydration step by heating in vapor phase and a supplying step to supply the catalyst subjected to the removing step to the hydration step. In the above process, at least a part of the zeolite catalyst is extracted from the hydration step or the removing step, contacted with an aqueous solution of an inorganic alkali, subjected to ion-exchange treatment and returned to the hydration step or the removing step.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of hydration reaction of olefins for producing alcohols important as various chemical raw materials.

[0002]

BACKGROUND OF THE INVENTION Hydration of olefins is a method of producing the corresponding alcohols from olefins and water. In the olefin hydration reaction using zeolite as a catalyst,
As the reaction progresses, organic substances mainly accumulate on the catalyst, so that the activity of the catalyst decreases. The catalyst with reduced activity is regenerated by removing the organic substances attached to the catalyst, and is used again for the olefin hydration reaction. As a method of removing the organic matter attached to the catalyst, a method of contacting with a gas containing molecular oxygen at a high temperature (Japanese Patent Publication No. 3-2015) and a method of contacting with an oxidant in a liquid phase (Japanese Patent Publication No. 3-2015).
No. 2014) are known.

[0003]

However, in the olefin hydration reaction method in which the hydration reaction and the regeneration of the catalyst by the removal of the organic matter by the vapor-phase heat treatment are repeated, the catalyst activity gradually decreases with repeated regeneration. There's a problem.

[0004]

Means for Solving the Problems The inventors of the present invention have made extensive studies in view of the above problems, and as a result of repeating the removal of organic substances by a hydration reaction and a gas phase heat treatment, a catalyst with reduced activity was identified as a specific catalyst. By contacting with a compound and then removing the cation species introduced from a specific compound by ion exchange treatment and converting it to the desired cation species, catalyst activity decline is suppressed and stable alcohol production is achieved over the long term. They have found what they can do and have completed the present invention.

That is, the gist of the present invention is a hydration step of hydrating an olefin in the presence of a zeolite catalyst, a removal step of removing organic substances attached to the zeolite catalyst used in the hydration step by a gas phase heat treatment, and In the olefin hydration method having a supply step of supplying the catalyst after the removal step to the hydration step, at least a part of the zeolite catalyst is extracted from the hydration step or the removal step, and the zeolite catalyst is brought into contact with an inorganic alkaline aqueous solution. Then, the method for hydrating an olefin is characterized by performing ion exchange and then returning to the hydration step or the removal step.

Hereinafter, the present invention will be described in detail. In the present invention, the zeolite catalyst used as a catalyst for the hydration reaction of olefins is not particularly limited as long as it is a zeolite that can be used as a catalyst, and examples thereof include mordenite, erionite, ferrierite, ZSM-5 and ZSM-11. Crystalline aluminosilicates such as ZSM type zeolites announced by Mobil, or metallosilicates such as borosilicates, gallosilicates and ferrosilicates, zeolites containing different elements such as aluminometallosilicates such as boroaluminosilicates, galloaluminosilicates and ferroaluminosilicates. Examples of known zeolites such as
Further, these zeolite catalysts are usually of the proton exchange type (H type), but some of them are Mg, Ca, S
alkaline earth elements such as r, rare earth elements such as La and Ce,
It may be exchanged with at least one kind of cation species selected from Group III elements such as Fe, Co, Ni, Ru, Pd and Pt. Alternatively, Ti, Zr, Hf, Cr, Mo,
You may contain W, Th, Cu, Ag, etc. The zeolite may be in any form, including powder and granules. Alumina, silica, titania, clay compounds and the like may be used as the carrier or binder.

The olefin used as a reaction raw material is usually a straight-chain or branched olefin having 2 to 12 carbon atoms such as propylene and butene, cyclopentene, methylcyclopentene, cyclohexene, cyclooctene and the like having 5 to 5 carbon atoms. There are 12 cyclic olefins, preferably cyclic olefins. As the hydration conditions of the olefin, the reaction temperature and the reaction pressure are not particularly limited as long as the catalyst exists in the aqueous phase, the oil phase or the liquid phase composed of the mixed phase of both. The reaction temperature is usually 50 to 250 ° C,
100 to 200 when the olefin is a cyclic olefin
C is preferred. The reaction may be carried out batchwise or continuously, but is preferably continuous. The molar ratio of olefin to water in the reaction system is usually 0.01
-100, preferably 0.03-10. The weight ratio of the catalyst to the olefin in the reaction system is usually 0.005 to 100, preferably 0.05 to 10. The residence time of the olefin during the reaction is usually 3 to
It is 300 minutes, preferably 10 to 180 minutes.

The olefin hydration reaction system is preferably replaced with an inert gas such as nitrogen, hydrogen, helium, argon or carbon dioxide. Furthermore, in addition to olefin and water which are reaction raw materials, ethanol, acetone,
Reaction system of aliphatic hydrocarbons such as acetic acid, benzoic acid, cyclohexane, benzene, phenol, fluorobenzoic acid, sulfolane and their derivatives, aromatic hydrocarbons, oxygen-containing organic compounds, sulfur-containing organic compounds, halogen-containing organic compounds, etc. You may coexist in the inside.

An example of a method for separating the reaction liquid into an aqueous phase and an oil phase is a method in which an oil / water separation weir is provided in the reactor and only the oil phase is taken out. It is also conceivable to take out a part of the reaction liquid with a liquid circulation pump and supply it to an oil / water separation tank provided outside the reactor to separate it.The separated aqueous phase containing the catalyst circulates in the reactor. Can be reused. The alcohol can be easily purified and recovered from the separated oil phase by a known method such as distillation. Further, the residual liquid containing the olefin after the alcohol is separated by distillation or the like can be reused as a raw material for the hydration reaction.

As described above, the catalyst activity of the zeolite catalyst used in the hydration step gradually decreases due to the attachment of organic substances on the catalyst as the hydration reaction progresses. A part or all of the zeolite catalyst whose activity has decreased with the progress of the hydration reaction is extracted from the hydration step, and the catalytic activity is recovered by the removal step of removing the organic matter attached to the surface. The catalyst extracted from the hydration step may be washed with water or dried prior to the removal step.

The removal of the organic substances adhering to the surface of the zeolite catalyst is carried out by gas phase heat treatment. As the gas-phase heat treatment, the method disclosed in Japanese Patent Publication No. 3-2015 can be used, and specifically, the zeolite catalyst extracted from the hydration step is a gas containing molecular oxygen. And a method of contacting with a high temperature, for example, the following method. The heating device may be of any type such as a general tubular furnace or a muffle furnace, and is preferably one capable of performing contact operation with gas in a fixed bed or fluidized bed form by a gas flow method. The oxygen concentration of the gas containing molecular oxygen is usually 0.01 to 90 mol%, preferably 1 to 30 mol%. As the gas component other than molecular oxygen, nitrogen, helium, argon or the like is usually used,
It is desirable that the water content in the gas be removed in advance. Further, in the case of the gas flow method, the gas flow rate is expressed as weight hourly space velocity (WHSV) with respect to the zeolite catalyst, and is usually 0.
It is carried out at 25 to 50 hr ^-1 . The conditions for vapor phase heat treatment are
Contact temperature is usually 200-600 ° C, contact time is usually 1-
It is 100 hours, preferably 2 to 20 hours. The vapor phase heat treatment may be either a constant temperature treatment or a temperature variable treatment,
Temperature variable treatment is preferred. Particularly, a temperature variable treatment which is performed separately in low temperature treatment and high temperature treatment is preferable.

[0012] The activity of the zeolite catalyst can be almost recovered by the removal step of removing the organic matter attached to the zeolite catalyst by the gas phase heat treatment. The catalyst that has undergone the removal step is partially or wholly supplied to the hydration step and used again as a hydration catalyst. However,
If the hydration step and the removal step are repeated several times, the activity of the zeolite catalyst will not gradually recover even if the removal step is performed.

It is presumed that organic substances, which are difficult to remove even after repeated removal steps, gradually accumulate. Further, even if the organic substance itself can be removed by the high temperature calcination, the organic substance or its decomposition product interacts with the active site of the catalyst, and part of the structure of the zeolite is altered.
It is considered that some of the active sites effective as a catalyst are lost.

In the present invention, as described above, the hydration step,
By repeating the removal step and the supply step, at least a part of the zeolite catalyst whose activity has not been sufficiently recovered is extracted from the hydration step or the removal step, brought into contact with an inorganic alkaline aqueous solution, and then the inorganic material introduced into the zeolite. It is characterized in that the cation species derived from the inorganic alkali in the aqueous alkali solution is ion-exchanged to reactivate the zeolite catalyst.

The reason why the activity is recovered by contact with an aqueous solution of an inorganic alkali is not clear. However, contact with an aqueous solution of an inorganic alkali repairs degenerated acid points or dissociates the desorbed aluminum and the like in the zeolite. It is considered that the acid site, which is the active site, is modified by the action of returning to the skeleton or removing it. If the catalyst is regenerated by contacting with an inorganic alkaline aqueous solution without performing the organic substance removing step, the acid sites of the zeolite catalyst can be activated, but the organic substances attached to the zeolite catalyst cannot be sufficiently removed. For this reason, it is difficult to suppress the decrease in catalyst activity when the regeneration is repeated.

The removing step is performed more frequently than the step of contacting with the inorganic alkaline aqueous solution. For example, when the catalyst is continuously withdrawn, the activity of the catalyst in the reaction step can always be kept constant, so that a certain amount of the catalyst withdrawn from the reaction step or the removal step is always contacted with the inorganic alkaline aqueous solution. It is desirable to provide it to the step of In this case, the ratio of the catalyst to be subjected to the step of contacting with the inorganic alkaline aqueous solution is appropriately set depending on the productivity of the reaction, economic efficiency, and further varies depending on the hydration reaction conditions, the amount of organic substances attached to the catalyst, and the like. Usually 0.1% or more based on the total amount of the catalyst extracted from the reaction step or the removal step,
It is preferably performed at 1% or more, and usually 99% or less, preferably 95% or less. The activity of the zeolite catalyst after the removal step is usually 40% or more, preferably 50% of the activity of the catalyst when the catalyst is used for the first time.
It is desirable to bring the zeolite catalyst into contact with the aqueous inorganic alkali solution when the amount of the catalyst is reduced to the above level and usually 99% or less, preferably 95% or less.

The inorganic alkaline aqueous solution used in the present invention is not particularly limited as long as it is an aqueous solution of an alkaline inorganic salt, and examples thereof include an alkali metal hydroxide, an alkali metal carbonate, an alkali metal hydrogen carbonate and an alkaline earth. It is an aqueous solution of a metal hydroxide, an alkaline earth metal carbonate, and an alkaline earth metal hydrogen carbonate. The amount of the inorganic salt in the aqueous inorganic alkaline solution varies depending on the level of deterioration of the zeolite catalyst, but is usually 0.01 to 10 equivalents, preferably 0.1 to 5 equivalents per 1 kg of the zeolite catalyst. If the amount of the inorganic salt is less than 0.01 equivalent per 1 kg of the zeolite catalyst, the reactivating effect is small, and if it is more than 10 equivalent, the alkalinity is too strong and the crystal destruction due to the dissolution of the zeolite is not preferable.

The amount of the inorganic alkaline aqueous solution used is not particularly limited as long as the amount of the inorganic salt is within the above range, but is usually 0.1 to 1000 times by weight, preferably 1 to 100 times by weight, relative to the zeolite. Double. The contact temperature is usually 10
The temperature is 200 ° C, preferably 20 to 160 ° C. The contact time varies depending on the state of deterioration of the zeolite and the contact temperature, but is usually 1 minute to 20 hours, preferably 15 minutes to 10 hours. The contact method may be a fixed bed or a slurry state. It is preferable that stirring is performed in a slurry state so that uniform contact can be achieved.

The treatment with this inorganic alkaline aqueous solution must be carried out under the condition that dissolution of zeolite and crystal destruction do not occur remarkably. Therefore, it is important to carefully select the conditions for the treatment with the inorganic alkaline aqueous solution from the above conditions depending on the state of deterioration of the zeolite. For example, 120
At a high temperature of about ℃, even if the same concentration of the inorganic alkaline aqueous solution is used, the zeolite is more easily dissolved than at the low temperature, so the concentration of the inorganic alkaline salt in the inorganic alkaline aqueous solution is 0.5 N or less. Need to

The zeolite catalyst brought into contact with the aqueous solution of inorganic alkali is ion-exchanged with cations derived from the inorganic alkali in the aqueous solution of inorganic alkali. This cation in the zeolite catalyst is removed by an ion exchange treatment and converted into a desired cation species, and then used in the olefin hydration reaction. Washing and drying may be performed before ion-exchange of the cations.

The cation species exchanged with the cation species derived from the inorganic alkali introduced into the zeolite catalyst are usually protons, alkaline earth elements, rare earth elements,
At least one cationic species selected from Group VIII elements is used. The method of ion exchange treatment is not particularly limited, but it depends on the cation species after ion exchange, and when the cation species is a proton, an aqueous solution of an acid such as hydrochloric acid, nitric acid or sulfuric acid is used, or ammonium ion is used. A method of removing ammonia by performing a gas phase heat treatment after the exchange type is adopted. When the cation source is a metal ion, an aqueous solution of a corresponding cation such as hydrochloride, nitrate or sulfate is used.

The concentration of the acid aqueous solution or the metal salt aqueous solution in the case of ion exchange with the acid aqueous solution or the metal salt aqueous solution varies depending on the type of the acid or the metal salt used, but is usually 0.0001 to
It is 10 mol / l. Furthermore, the amount ratio of the acid or metal salt to the zeolite used is expressed by the value of the ratio of the number of moles of the acid or metal salt to the exchange capacity of the zeolite, and is usually 0.1 to 0.1.
100. The pressure during the ion exchange treatment is usually atmospheric pressure, but the treatment may be performed under reduced pressure or under increased pressure. If the liquid temperature during ion exchange treatment is atmospheric pressure,
Usually, 0 to 100 ° C is used. Processing time is usually 0.1
~ 100 hours are used. Further, the ion exchange treatment may be repeated.

As the ion exchange method, usually, the zeolite catalyst is immersed in the above acid aqueous solution or metal aqueous solution, and the exchange is carried out by stirring or standing. Also, the exchange can be promoted by sprinkling the above-mentioned acid aqueous solution or metal aqueous solution on the zeolite catalyst.
The zeolite catalyst thus ion-exchanged may be washed with water, dried, etc. before being again used for the olefin hydration reaction.

When the ion exchange treatment is changed to the ammonium ion exchange type and then the proton exchange type is obtained by desorbing ammonia by the gas phase heat treatment, the method conditions of the gas phase heat treatment are the above-mentioned organic substances. The same method and conditions as the gas phase heat treatment in the removal step can be performed. In the present invention, a method of desorbing ammonia by gas phase heat treatment after ion exchange is changed to ammonium ion type, and a proton exchange type is used, the gas phase heating device is shared by the ion exchange and organic substance removal steps. It is possible and is industrially advantageous.

The zeolite catalyst which has been brought into contact with the inorganic alkali aqueous solution and then ion-exchanged is returned to the hydration step or the removal step, preferably the hydration step, and used again as a catalyst for the olefin hydration reaction. .

[0026]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the scope of the present invention. Comparative 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 gallosilicate (SiO ₂ / Ga ₂ O ₃ atomic ratio = 50/1) and 250 g of water were charged as a hydration catalyst into a stainless steel autoclave reactor 3 having an internal volume of 2000 ml and equipped with a stirrer, and the system was charged. The atmosphere was replaced with nitrogen gas. While stirring at a rotation speed of 500 rpm, the temperature inside the reactor 3 was raised to a reaction temperature of 120 ° C., and then cyclohexene (reagent: manufactured by Aldrich) from the supply pipe 1
Was fed at a rate of 120 g / h. After the reaction liquid is separated into an oil phase and a catalyst slurry aqueous phase in a liquid-liquid separator 4 having an internal volume of 30 ml provided inside the reactor, only the oil phase flows out of the overflow pipe 5. Further, the total amount of water consumed in the hydration reaction and the water flowing out from the overflow pipe 5 as the amount of solubility in the oil phase is supplied from the supply pipe 2 so that the amount of water in the reactor 3 is kept constant. I kept it. The concentration of cyclohexanol in the spilled oil 5 hours after the start of feeding the starting material cyclohexene was 10.1% by weight. Also, 2
The cyclohexanol concentration in the spilled oil after the lapse of 00 hours was 4.5% by weight.

{Removal of catalyst organic matter by vapor phase heat treatment}
Cyclohexene Continuous Flow Hydration Reaction After 200 hours, the catalyst was filtered, washed with water, dried, filled in a quartz glass reaction tube, and a mixed gas consisting of 4 mol% oxygen and the balance nitrogen at a flow rate of 150 Nl / h. 5 at 500 ° C while flowing at atmospheric pressure at
After heating for an hour, the system was cooled and the catalyst was taken out. The catalyst after the vapor-phase heat treatment was pure white, and no carbon component was found even after analysis with a CHN analyzer.

{Repeat of organic matter removal and continuous flow hydration reaction} Continuous flow hydration reaction and organic matter removal are repeated four times using the same catalyst under exactly the same hydration reaction conditions and gas phase heat treatment conditions as above. It was After the second to fifth organic matter removal, all the catalysts were pure white, and no residual carbon component was observed even when analyzed by a CHN analyzer. Cyclohexanol concentration in the effluent oil was 7.3% by weight at the fifth hour of the continuous flow hydration reaction using the catalyst after the fifth organic matter removal.

Example 1 The catalyst after the fifth organic matter removal, which was obtained by repeating the continuous flow hydration reaction and the organic matter removal by the vapor-phase heat treatment in the same manner as in Comparative Example 1, was used in an amount of 0.3N of 10 times the dry weight of the catalyst. -In a sodium hydroxide aqueous solution, stirring was performed while maintaining the temperature at 80 ° C for 1 hour.

Thereafter, the catalyst was filtered, washed with water, and then stirred in an aqueous 1N-ammonium nitrate solution in an amount 10 times the dry weight of the catalyst for 2 hours while maintaining the temperature at 100 ° C. Then, the catalyst was filtered and washed with water, and the treatment with the ammonium nitrate aqueous solution was repeated twice. Then, after drying the catalyst, it was filled in a quartz glass tube, heated at 500 ° C. for 2 hours while flowing air at a flow rate of 150 Nl / h at normal pressure, cooled, and taken out as an H-type catalyst.

Using this catalyst, a continuous flow hydration reaction was carried out under the same reaction conditions as in Comparative Example 1 {continuous flow hydration reaction of cyclohexene}. The cyclohexanol concentration in the effluent oil at the fifth hour of the continuous flow hydration reaction was 10.0% by weight.

[0032]

EFFECT OF THE INVENTION According to the method of the present invention, the olefin hydration reaction can be carried out while remarkably suppressing the decrease in the activity of the catalyst, which is very advantageous in industrial practice.

[Brief description of drawings]

FIG. 1 is a continuous flow reactor used in Example 1 and Comparative Example 1.

[Explanation of symbols]

 1. Cyclohexene supply pipe 2. Water supply pipe 3. Autoclave reactor 4. Liquid-liquid separator 5. Overflow pipe

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location // C07B 61/00 300 C07B 61/00 300

Claims (4)

[Claims] 1. A hydration step of hydrating an olefin in the presence of a zeolite catalyst, a removal step of removing organic substances attached to the zeolite catalyst used in the hydration step by a gas phase heat treatment, and a catalyst which has undergone the removal step. In the olefin hydration method having a supply step of supplying to the hydration step, at least a part of the zeolite catalyst is extracted from the hydration step or the removal step, the zeolite catalyst is contacted with an inorganic alkaline aqueous solution, and then ion exchanged, A method for hydrating an olefin, which comprises returning to a hydration step or a removal step. 2. The olefin hydration method according to claim 1, wherein the inorganic alkali aqueous solution is an aqueous solution of an alkali metal hydroxide. 3. The method for hydrating an olefin according to claim 1 or 2, wherein the ion exchange is carried out by exchanging the ammonium ion type with a proton exchange type by a gas phase heat treatment. 4. The gas phase heat treatment is carried out by bringing the zeolite catalyst into contact with a gas containing molecular oxygen at 200 to 600 ° C.
The method for hydrating an olefin according to any one of items.