JPH0753422A - Production of alcohol and catalyst used therefor - Google Patents

Abstract

PURPOSE:To provide a method for producing an alcohol using a solid acidic catalyst, remarkably improved in hot water-resistant stability and having high contents of an acid and a strong acid in hydrating reaction of an olefin and the solid acidic catalyst, used therefor and excellent in water resistance and thermal stability. CONSTITUTION:The characteristic of this method for producing an alcohol comprises using a solid acidic catalyst composed of niobic acid particles having >=1mum average particle diameter, <=-3.0 acidity function H0 and >=0.35mmol/g acid content (A) in which >=50% of the acid content (A) is the content (B) of strong acids having <=-5.6 H0 and further <=10% rate of reduction in the content (A) of the acids after testing the hot water resistance at 350 deg.C or a dehydrated substance thereof, in a method for reacting an olefin with water in the presence of the acidic catalyst and producing the alcohol.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing an alcohol by hydration of an olefin and a catalyst used therefor.

[0002]

It is known to react water directly with olefins at elevated temperatures in the presence of acid catalysts to produce alcohols. In this case, the catalyst used is a porous carrier impregnated with phosphoric acid.
However, in such a catalyst, since phosphoric acid is released from the carrier during the reaction, there is a problem of device corrosion and product coloring due to the phosphoric acid, a problem of separation and recovery of the released phosphoric acid, There are problems such as waste acid treatment. Furthermore, the reaction system has a problem that it must be supplemented with phosphoric acid from the outside by reacting with the phosphoric acid component released from the carrier and discharged to the outside of the reaction system. As described above, in the case of the process using the catalyst in which the porous carrier is impregnated with phosphoric acid, various problems are caused and it is not yet satisfactory. on the other hand,
In order to counter such problems, a method using a solid acid as a catalyst has been proposed. Zeolite is generally used as the solid acid in this case.
3-15485 and JP-A-57-70828. ) The use of solid acids with a large amount of acid such as niobium acid and tungstic acid has been investigated, but these solid acids deactivate the solid acid function in a high temperature reaction system in the presence of water. For example, in the case of niobic acid, it is considered that the cause thereof is that conventional niobate particles are unstable, and therefore, when they are heated in the presence of water, they are transformed into other substances. In order to improve the stability of the niobate particles, a method of heat-treating the niobium particles at high temperature in the absence of water is effective, but in this case, the obtained niobate particles lose the solid acid function. Since it has been lost, it cannot be used as a solid acid catalyst. In addition, a method of impregnating niobate particles with phosphoric acid (Japanese Patent Application Laid-Open No. 61-54241) has also been proposed. In this case, when the niobate particles are used, the phosphoric acid is niobate. There is a problem that the niobate particles are released from the particles and destabilize the niobate particles again.

Conventionally, in order to obtain niobate particles, a method of adding an alkaline aqueous solution to a niobium oxalate aqueous solution is known (“Catalysis Toda”).
y ", Vol 16, 291-295 (1993)).
The niobate particles obtained by such a conventional method are fine particles containing niobium oxalate particles, and the average particle diameter thereof is usually 1 μm or less. Therefore, such niobate particles are easily made into a colloid in water, their separation by filtration is very difficult, and their handleability is very poor. Moreover, the hydrothermal resistance of the niobate particles obtained by such a conventional method is very poor, and after the hydrothermal resistance test at 350 ° C., the acid strength function Ho is 10% of the acid amount of −3.0 or less.
The above disappears. Therefore, the niobate particles obtained by the conventional method cannot be applied as they are as a solid acid catalyst used in a high temperature reaction system in which water is present.

[0004]

DISCLOSURE OF THE INVENTION The present invention is directed to a method for producing an alcohol using a solid acid catalyst having a large amount of the acid and the strong acid, which has remarkably improved thermal stability in an olefin hydration reaction, and a hydrothermal resistance used therefor. It is an object of the present invention to provide a solid acid catalyst having excellent stability.

[0005]

The present inventors have completed the present invention as a result of intensive studies to solve the above problems.

That is, according to the present invention, in the method for producing an alcohol by reacting an olefin with water in the presence of an acid catalyst, the acid catalyst has an average particle size of 1 μm or more and an acidity function Ho: An acid amount A of −3.0 or less is 0.35 mmol / g or more, and 5 of the acid amount A
Solid acid catalyst consisting of niobate particles or dehydration product thereof, in which 0% or more has a strong acid amount B of Ho: -5.6 or less and the reduction amount of acid amount A after a hydrothermal resistance test at 350 ° C is 10% or less. A method for producing alcohol is provided, which comprises using

According to the present invention, in addition to having an average particle size of 1 μm or more and an acid amount A having an acidity function Ho: −3.0 or less of 0.35 mmol / g, of the acid amount A, 50% or more is a strong acid amount B of Ho: -5.6 or less,
And the reduction rate of acid A after the hydrothermal resistance test at 350 ° C is 10%
A catalyst for alcohol production by hydration of an olefin comprising the following niobate particles or a dehydrated product thereof is provided.
Hereinafter, the method for producing niobate particles according to the present invention will be described in detail.

(First Method) The first method for producing niobate particles according to the present invention comprises: a niobium compound-dissolved or undissolved alkaline aqueous solution having a pH of more than 11; It includes a mixing step of gradually adding the acidic aqueous solution. in this case,
The raw material niobium compound needs to be dissolved at least in an acidic aqueous solution. In addition, the alkaline aqueous solution is
The niobium compound can be preferably dissolved in this alkaline solution as long as H is maintained in the range of more than 11. Then, by preliminarily dissolving the niobium compound in the alkaline aqueous solution, it is possible to obtain niobate particles having good properties with a small amount of the acidic aqueous solution.
In addition, the mixing of the acidic aqueous solution with the alkaline aqueous solution,
The pH of the finally obtained mixed solution is adjusted to 5.5 to 11.0, preferably 6.0 to 10.0. As the alkaline aqueous solution, any alkaline solution having a pH of more than 11, preferably a pH of more than 11.5 can be used. Generally, sodium hydroxide or potassium hydroxide is used. An aqueous solution of alkali hydroxide is used. In this case, the concentration of alkali hydroxide in the alkaline aqueous solution is not particularly limited, but is generally 0.1 to 15 N, preferably 0.2 to 1
There are two rules. In a preferred embodiment of the present invention, as described above, the niobium compound is dissolved in the alkaline aqueous solution, but any niobium compound may be used as long as it is soluble in the alkaline aqueous solution. It is possible. Examples of such niobium compounds include niobate, and niobium oxalate and niobium acetate. The concentration of the niobium compound in the alkaline aqueous solution is not particularly limited as long as it is equal to or lower than its saturation concentration, but generally 1 to
It is 50% by weight, preferably 2 to 20% by weight.

As the acidic aqueous solution, any solution can be used as long as it shows an acidity of pH 5 or less. Generally, inorganic acids such as sulfuric acid, nitric acid and phosphoric acid, oxalic acid and acetic acid are used. An aqueous solution of an organic acid such as tartaric acid, citric acid, malic acid and fumaric acid is used. Further, when an acid containing halogen is used, caution is required because halogen ions may remain in the product. The acid concentration in the acidic aqueous solution is not particularly limited, but generally 0.1 to
It is 15 normal, preferably 0.2 to 12 normal. In the present invention, the niobium compound is dissolved in this acidic aqueous solution. In this case, any niobium compound can be used as long as it can be dissolved in the acidic aqueous solution. As such a niobium compound, for example,
In addition to niobate, niobium oxalate, niobium acetate, and other organic acid niobium can be used. The concentration of the niobium compound in the acidic aqueous solution is not particularly limited as long as it is equal to or lower than its saturation concentration, but is generally 0.5 to 30% by weight, preferably 1 to 20% by weight.

In the present invention, an alkaline aqueous solution in which the niobium compound is dissolved or not dissolved is mixed with an acidic aqueous solution in which the niobium compound is dissolved under stirring to obtain a mixed solution consisting of a niobate precipitation solution. In this case, the pH of the mixed solution is 5.5 to 11.
It is adjusted to 0, preferably 6.0 to 11.0. Further, in this case, it is necessary to adjust the pH of the mixed solution so that the pH of the mixed solution changes from a higher value to a lower value. For this purpose, the acidic aqueous solution may be gradually added to the alkaline aqueous solution. If an acidic aqueous solution is added to the alkaline aqueous solution at a time, new niobic acid nuclei are generated in addition to the growth of niobic acid, and a pH range lower than the precipitation region of niobic acid (pH 5.
(Less than 5) locally occurs, and particles of niobium compounds other than the desired niobate particles, for example, when an aqueous niobium oxalate solution is used as the acidic aqueous solution, the niobium oxalate precipitates as fine particles. The niobate particles containing such fine niobium oxalate particles do not give a product having good hydrothermal resistance. In the present invention, the addition rate of the acidic aqueous solution is such that the average pH drop rate of the mixed solution is 0.2 / min or less, preferably 0.01 to 0.1 / min. It is better to adjust. The temperature of the mixed solution is maintained at room temperature to 100 ° C, preferably room temperature to 95 ° C.

When an acidic aqueous solution is added to and mixed with an alkaline aqueous solution in the present invention, an acidic aqueous solution having a pH of 5 or less in which a niobium compound is dissolved is added to a mixed solution (niobic acid precipitation solution) obtained by the mixing. An alkaline aqueous solution having a niobium compound dissolved or not dissolved therein and having a pH of 11 or more is adjusted to pH 5.5 to 1
It can be added while being maintained in the niobate precipitation region of 1.0. In this way, niobate particles having a large particle size obtained by growing niobate particles can be obtained.
In this case, the addition of the acidic aqueous solution and the alkaline aqueous solution is
It is preferable that the average pH drop rate of the mixed solution is 0.2 / min or less.

(Second Method) A second method for producing niobate particles according to the present invention is a method of producing niobate particles containing a pH of 5.5 to 5.5.
The pH of the mixed solution is 5.5 to 1 with respect to the mixed solution of 11.0.
An operation of alternately repeating the step of adding and mixing the alkaline aqueous solution and the step of adding and mixing the acidic aqueous solution while maintaining the niobic acid precipitation region of 0.5 is included. By such an operation, niobate particles having a uniform particle size can be obtained. In this case, the pH fluctuation of the mixed solution by alternate addition of the alkaline aqueous solution and the acidic aqueous solution should be changed to 2 or more, preferably 4 or more. Further, the addition rates of the acidic aqueous solution and the alkaline aqueous solution in this case are not particularly limited.

The raw material mixed solution containing the niobate particles can be obtained by various methods as long as it is obtained by a method of adding and mixing an acidic aqueous solution to an alkaline aqueous solution. In this case, the particle size of the niobate particles in the raw material mixture is not particularly limited. The raw material mixed solution used in the present invention can be a mixed solution containing niobate particles having an average particle size of 1 μm or more obtained by the above-mentioned first method. By repeatedly adding and mixing an alkaline aqueous solution and an acidic aqueous solution to such a raw material mixture, niobic acid particles having a uniform particle size can be obtained. Further, by dissolving the niobium compound in at least one of the alkaline aqueous solution and the acidic aqueous solution to be added to the raw material mixed solution, the niobate particles contained in the raw material mixed solution have a larger particle size than the niobate particles contained in the raw material mixed solution, resulting in a sharp particle size distribution. Niobate particles can be obtained. The raw material mixture used in the present invention can be a mixture containing niobate particles having an average particle size of less than 1 μm. Such a mixed solution can be obtained by using a solution of a niobium compound dissolved in at least one of an alkaline aqueous solution and an acidic aqueous solution to be mixed, and adding and mixing the acidic aqueous solution to the alkaline aqueous solution. In this case, the addition rate of the acidic aqueous solution to the alkaline aqueous solution is not particularly limited. When an alkaline aqueous solution and an acidic aqueous solution are alternately added to a mixed solution containing niobate particles having an average particle diameter of 1 μm or less, by dissolving the niobium compound in at least one of the aqueous solutions,
It is possible to obtain niobate particles having a particle size larger than that of the niobate particles contained in the raw material mixture and having an average particle size of 1 μm or more.

FIG. 1 shows an example of a flow sheet of a niobate particle production process by a pH variation method involving pH variation of a mixed solution. In FIG. 1, 1 and 2 are containers, 3 and 4 are mixers, and 5 and 6 are pumps. In order to produce niobate particles according to the flow sheet shown in FIG. 1, first, a container 1 is lined with a mixed solution (niobate precipitation solution) containing niobate particles kept alkaline at pH 7.5 to 11.0. Fill via 15. Next, the flow rate of this mixed solution is controlled by the transfer pump 5 and the flow rate control valve 7,
Supply to the mixer 3. On the other hand, at the same time, the acidic aqueous solution is supplied from the acidic aqueous solution supply line 13 to the mixer 3 through the acidic pH control valve 11 to uniformly mix the alkaline mixed solution. The addition rate of the acidic aqueous solution in this case is not particularly limited. The two liquids that have been uniformly mixed are subjected to pH measurement by an acidic pH detector 9, the pH of the mixed liquid is controlled to a predetermined pH by an acidic pH control valve 11, and then sent to the acidic container 2. The mixed solution whose pH is adjusted to the acidic side is held in the container 2 for a certain period of time. The holding time in this case is a time for the pH in the system to become uniform, and is usually 0.5 to 30 minutes, preferably 1 to 10 minutes, and the holding temperature is from room temperature to 100.
C., preferably room temperature to 95.degree. Next, the pH of the mixed liquid held in the container 2 and adjusted to the acidic side is controlled by the transfer pump 6 by the flow control valve 8 and supplied to the mixer 4. On the other hand, at the same time, the alkaline aqueous solution is fed from the alkaline aqueous solution supply line 14 to the pH control valve 12 on the alkaline side.
To the mixer 4 to uniformly mix the two liquids. In this case, the addition rate of the alkaline aqueous solution is not particularly limited. The pH of this mixed solution is measured by the alkaline pH detector 10 and controlled by the alkaline pH control valve 12 to a predetermined pH value. Then, the mixed solution whose pH is adjusted to the alkaline side is held in the container 1 for a certain period of time. The holding time in this case is usually 0.5 to 30 minutes, preferably 1 to 10 minutes when the pH in the system becomes uniform, and the holding temperature is room temperature to 100 ° C., preferably room temperature to
95 ° C. Next, the pH of the mixed solution whose pH has been adjusted to the alkaline side is adjusted to the acidic side by the acidic aqueous solution from the line 13 as described above, and is transferred to the container 2.
By repeating this cycle, niobate particles having a uniform particle size are manufactured. The mixed liquid containing niobic acid particles is recovered via the line 16. Further, by dissolving a niobium compound in at least one of the alkaline solution and the acidic solution, it is possible to obtain niobate particles having a uniform particle size and having grown particles.

In the present invention, the number of times the pH of the mixed solution is changed (the number of pH changes), that is, the number of operation cycles for transferring the mixed solution from the container 1 to the container 2 and then again to the container 1 is at least Once, usually 2 to 50 times. The number of operation cycles affects the particle size, pore size and pore volume of the obtained niobate particles. Generally p
As the number of H fluctuations increases, the particle size of the obtained niobic acid becomes uniform and the pore size increases. Therefore, the number of pH changes is appropriately selected depending on the desired properties of the niobate particles. When obtaining niobate particles with an extremely large pore size,
It may be 50 times or more. The mixed solution containing niobate particles obtained as described above is subjected to solid-liquid separation treatment to recover niobate particles. In this case, it is preferable that the mixed liquid used for the solid-liquid separation treatment is adjusted to have a pH in the range of 6.0 to 10.0, which is the pH range in which the niobate particles are most stably present. As the solid-liquid separation method, a conventional method, for example, a filtration method, a sedimentation method, a centrifugation method or the like can be adopted.

The niobate particles thus obtained are post-treated by a conventional method to give niobate particles having a function as a solid acid. The post-treatment of the niobate particles for imparting the solid acid function generally includes a step of washing the niobate particles obtained by the solid-liquid separation treatment with water and a step of cation exchange treatment. The cation exchange treatment is
This is a step of exchanging alkali metal ions bonded to niobate particles as niobate for hydrogen ions, whereby niobate particles exhibiting a function as a solid acid can be obtained. The cation exchange treatment can be performed by bringing the niobate particles into contact with an aqueous nitric acid solution or an acidic aqueous solution such as an aqueous sulfuric acid solution. In this case, when an acid containing halogen is used in the acidic aqueous solution, halogen ions may remain, so care must be taken. When the niobate particles are washed with water, the washing water may be 40 to 10 if necessary.
Warmed water heated to 0 ° C. can be used, and boiling water is preferably used. When the niobate particles are subjected to cation exchange treatment, a solution heated to 40 to 100 ° C. can be used as the acidic aqueous solution. The amount of alkali remaining in the niobate particles which have been washed with water and subjected to cation exchange treatment is preferably 5 mol / 10,000 or less, and more preferably 5 mol / 100,000 or less, per 1 g of dry niobate particles. . The alkali remaining on the niobate particles neutralizes the strong acid points of the niobate particles and reduces the solid acid function of the niobate particles. The presence of cations other than hydrogen ions such as ammonium ions and other metal ions in the niobate particles is also not preferable. These cations also reduce the function of the niobate particles as a solid acid. Therefore,
As the water, alkaline substance, acidic substance and the like used as the reaction raw material in the present invention, it is preferable to use a high-purity product having a small halogen content and free of impurity cations such as other metal ions and ammonium ions.

The niobate particles can be formed into various shapes such as a spherical shape, a pellet shape, a cylindrical shape, and a honeycomb shape by a usual method. The molding of the niobate particles can be performed before or after the above-mentioned water washing treatment or cation exchange treatment, and can be performed at any time after the niobate particles are dried or calcined. Niobate particles or molded articles thereof remove the water contained therein,
It can be dried or calcined to obtain the dehydrated product. Drying in this case can be performed by vacuum drying or blast drying at a temperature of room temperature to 180 ° C. The firing is performed at 180 to 500 ° C., preferably 200 to 4
It can be carried out at a temperature of 50 ° C. The firing in this case can be performed in air. When the firing temperature exceeds 500 ° C., the niobate particles undergo a phase change to niobium oxide and the acid sites disappear, so it is preferable to use a firing temperature of 500 ° C. or lower.

The niobate particles obtained by the present invention have a large particle size, unlike conventional niobate particles, and their average particle size is 1 μm or more, usually in the range of 2 to 50 μm. Therefore, the niobate particles of the present invention have an advantage that they can be easily separated and recovered from the mixed solution, and can be easily washed with water or cation exchanged. Conventional niobate particles have a fine average particle size of usually less than 1 μm and are colloided in water, which causes great difficulties in solid-liquid separation, water washing treatment, and cation exchange treatment. In the case of the niobate particles according to the invention, such difficulties do not occur. The niobate particles of the present invention can be separated by filtration with a filter paper having an opening of 1 μm. In particular, when the niobate particles obtained by the pH variation method were filtered through a filter paper having an opening of 1 μm, no outflow of the niobate particles to the filtrate was observed.

Further, the niobate particles of the present invention are remarkably improved in thermal stability in the presence of water, and even in the hydrothermal resistance test, the crystal particles are not deteriorated and their function as a solid acid is lowered. There is no such thing. The acid amount A having a Ho (Hammett index), which is an acidity function of the niobate particles of the present invention, of -0.3 or less is 0.35 at 300 ° C. firing.
mmol / g or more, usually 0.35 to 0.70 mmol
/ G, and Ho for the acid amount A is -5.6.
The ratio of the following strong acid amount B is 50% or more, usually 55 to 85
%, The decrease in the acid amount A even after the hydrothermal resistance test at 350 ° C. is usually as small as 10% or less.
In addition, Ho (Hammett index) in the present specification is an acidity function, and is referred to as "catalyst experiment handbook" (198) edited by The Catalysis Society of Japan.
6 years, Kodansha Scientific), page 172, "Benesi method". In this case, the smaller Ho means the higher acid strength. In the present specification, an acid amount having Ho of −3.0 or less is defined as an acid amount of niobate particles, and an acid amount of Ho being −5.6 or less is defined as a strong acid amount.

As described above, the niobate particles of the present invention have a large average particle size of 1 μm or more, and the acid amount A of which Ho is −3.0 or less is 0.35 mmol when calcined at 300 ° C. / G or more, which is a large value. In the present invention, the niobate particles obtained by the pH variation method have a sharp particle size distribution and have particularly excellent performance as a solid acid catalyst.

To carry out the hydration reaction of olefins using the niobate particles or dehydrated product thereof obtained as described above as a catalyst, olefin and water are added in the presence of a catalyst composed of niobate particles or dehydrated product thereof. React. The reaction temperature varies depending on the olefin used, but generally 5
A reactivity of 0 to 450 ° C., preferably 80 to 400 ° C. is adopted. The reaction pressure is not particularly limited, and the olefin and water in the reaction system may be present in either the gas phase or the liquid phase, but in the case of the present invention, it is particularly advantageous to carry out the reaction in the gas phase. Is. In addition, the preferable reaction pressure is
10-100 kg / cm ² G, preferably 20-70 kg
/ cm ² G. As the reaction bed, any of a fixed bed and a fluidized bed can be adopted, but a fixed bed is preferably adopted.

The catalyst used in the present invention can be used in the form of a molded article such as a spherical shape, a cylindrical shape, or a pellet shape, in addition to the powder form. To obtain a molded article, niobate particles or a dehydrated product thereof may be molded as it is or in the form of a mixture with alumina, titania, silica, zirconia or the like in the presence of an appropriate amount of water or a binder. Good. Then, the obtained molded product is
After drying at 20 to 180 ° C, preferably 180 to 45
It is calcined at 0 ° C. and used as a catalyst. When the niobate particles are molded before being subjected to the cation exchange treatment, the obtained molded product may be subjected to the cation exchange treatment. The content of niobate particles or dehydrated product thereof in the molded product is at least 10
%, Preferably 30 to 100% by weight.
In the case of a fixed bed catalyst, the catalyst size is 0.2 to 20.
mm, preferably about 0.4 to 10 mm.

Examples of the olefin used as the reaction raw material include ethylene, propylene, 1-butene and 2-olefin.
Examples thereof include butene, pentene, hexene, heptene, octene, cyclobutene, cyclohexene, cyclododecene and the like. When the reaction of olefin and water is carried out in a fixed bed system, a gaseous mixture of olefin and water is passed through a fixed bed reactor. In this case, the molar ratio of water to olefin (H ₂ O / olefin) is 0.
It is 1 to 4.0, preferably 0.2 to 3.0. Also,
Gas hourly space velocity (GHSV) is 100 ~ 4000hr ^-1 ,
It is preferably 1000 to 3000 hr ⁻¹ . The reaction temperature varies depending on the type of olefin, but is generally 50
˜450 ° C., preferably 80˜400 ° C. When ethylene is used as the olefin, 100 to 400 ° C,
It is preferably 150 to 350 ° C.

[0024]

INDUSTRIAL APPLICABILITY The solid acid catalyst comprising niobic acid particles or its dehydration product used as a catalyst in the present invention has excellent hydrothermal resistance and shows an excellent catalytic effect for olefin hydration reaction at high temperature. Further, the catalyst of the present invention retains its catalytic property for a long time, and its catalyst life is very long.

[0025]

EXAMPLES The present invention will now be described in more detail by way of examples.

Reference Example 1 250 g of niobium oxalate was dissolved in an aqueous solution of oxalic acid (pH: 1.0) in which 125 g of oxalic acid was dissolved in 5 liters of water, and then impurities were separated by filtration to obtain an aqueous solution of niobium oxalate (pH). : 1.2) was prepared. Then, 5 liters of this niobium oxalate aqueous solution was stirred (rpm: 200) while stirring with a 4N potassium hydroxide aqueous solution (pH: 14).
It was added to 1.35 liters to obtain a mixed solution (precipitation solution) having a pH of 7.98. In this case, the niobium oxalate solution was gradually added so that the average pH drop of the mixed solution was 0.2 / min or less. After the precipitate contained in the thus obtained mixed solution was collected by filtration, the obtained precipitate was washed by immersion in 5 L of 0.1 N nitric acid twice, and then 5 L of boiling water was added. It was used for immersion cleaning twice. The average particle size of the niobate particles thus obtained is 3 μm.
Met. This was dried at 110 ° C. and then calcined at 300 ° C. in air to obtain a dehydrated product of niobate particles.

Next, with respect to the dehydrated product of niobic acid particles thus obtained, the acid amount, the acid amount after the hydrothermal resistance test and the acid amount reduction rate were determined as follows. The results are shown in Table 1. (Amount of acid) The amount of acid can be measured by "Catalysis Experiment Handbook" edited by The Catalysis Society of Japan (Published in 1986, Kodansha Scientific).
P. It was performed by the Benesi method described in 172. In this case, the amount of acid having a Ho of −3.0 or less was defined as the solid acid amount A, and the amount of acid having a Ho of −5.6 or less was defined as the strong acid amount B. (Hydrothermal resistance test) A stainless steel pipe having an inner diameter of 9.5 mm was filled with 10 g of a sample to form a packed layer, and 15 liter of steam heated to 350 ° C. was added to the packed layer.
After flowing at a flow rate of 24 hours, the sample was taken out, the acid amount A and the strong acid amount B were measured, and the acid amount A decrease rate was obtained. The rate of decrease of the acid amount A in this case was calculated by the following equation. Acid amount A decrease rate = {(A (I) -A (II) / A (I)} ×
100 (%) A (I): acid amount of sample before hydrothermal resistance test A (II): acid amount of sample after hydrothermal resistance test The hydrothermal resistance test referred to in the present specification means the above test. To do.

[0028]

[Table 1]

Reference Example 2 An experiment was carried out in the same manner as in Reference Example 1, except that the addition rate of the niobium oxalate aqueous solution was variously changed. Table 2 shows the average particle size of niobate particles and dehydrated products thereof.
The amount of acid before and after the hydrothermal resistance test is shown.

[0030]

[Table 2]

Reference Example 3 The niobium oxalate aqueous solution (pH 1.2) shown in Reference Example 1 was used.
0) 1.1 liter was added and mixed with 0.625 liter of the KOH aqueous solution (pH 14.00) shown in Reference Example 1 to obtain a transparent liquid having pH 14. Next, for this liquid,
A niobium oxalate aqueous solution (pH 1.20) and a KOH aqueous solution (pH 14.00) were alternately added and mixed at the addition amounts shown in Table 3 to finally obtain a mixed solution (precipitate solution) having a pH of 7.85.
Got In this case, niobium oxalate aqueous solution and KOH
The addition of the aqueous solution was performed immediately. After addition, each pH was maintained for 3 minutes. Table 3 also shows the pH of the mixed solution after addition of the niobium oxalate aqueous solution and the KOH aqueous solution.

[0032]

[Table 3]

Then, the pH of 7.85 obtained as described above is obtained.
The mixed solution of (1) was post-treated in the same manner as in Reference Example 1 to obtain niobate particles and its dehydrated product. The niobate particles thus obtained had an average particle size of 3.0 μm and contained no particles of 1 μm or less. Table 4 shows the properties of this dehydrated product.

[0034]

[Table 4]

Comparative Reference Example 1 With respect to 5 liters of the niobium oxalate aqueous solution shown in Reference Example 1, 1.35 liters of the KOH aqueous solution shown in Reference Example 1 was stirred to obtain an average pH increase rate of 0.2 /. Gradually added and mixed in minutes. The obtained mixed liquid was post-treated in the same manner as in Reference Example 1 to obtain a dehydrated product of niobium particles. As a result of measuring the acid amount A and the acid amount A reduction rate before and after the hydrothermal resistance test of this product, the acid amount A before the test was 0.30 mmol / g, and the acid amount A after the test was 0.24 mmol / g, The acid amount A reduction rate was 20%.

Example 1 Experiment No. 1 of Reference Example 1 and Reference Example 2. 1-3 and Reference Example 3
Each of the dehydrated products of 5 kinds of niobic acid particles obtained from Example 1 was tablet-molded and then sized to 16 to 24 mesh, and the obtained catalyst was used for ethanol synthesis by hydration of ethylene in a flow reactor. . The catalyst amount was 10 ml, and the reaction conditions were pressure: 30 kg / cm ² G, temperature: 280 ° C., molar ratio of water to ethylene as a raw material: 1.0, GHSV: 1
We adopted 500 hr ^-1 . Prior to the reaction, the catalyst is 300
Exhaust treatment at ℃ for 1 hour, then ² at 35kg / cm ² G
Distribution processing was carried out by GHSV: 750 hr ^{-1 by} time steam. The reaction products were all quantified by chromatography. All of the catalysts showed stable activity with no decrease in activity observed 100 hours after the initiation of the reaction. Table 5 shows the reaction results at that time.

[0037]

[Table 5]

Comparative Example 2 Experiment No. 2 of Reference Example 2. The two types of niobate particles obtained from Example 4 and Comparative Reference Example 1 were used for ethanol synthesis by hydration of ethylene as in Example 1. A decrease in activity was observed for these two catalysts 100 hours after the start of the reaction.
The results after 100 hours are shown in Table 6.

[0039]

[Table 6]

[Brief description of drawings]

FIG. 1 shows an example of a flow sheet of a method for producing niobate particles by a pH fluctuation method.

[Explanation of symbols] 1, 2 container 3, 4 mixer 5, 6 pump

Claims (5)

[Claims] 1. A method for producing an alcohol by reacting an olefin with water in the presence of an acid catalyst, wherein the acid catalyst has an average particle size of 1 μm or more and an acidity function Ho: −3.0 or less. Acid amount A is 0.35 mmol / g
And more than 50% of the acid amount A is Ho:-
A solid acid catalyst comprising niobate particles having a strong acid amount B of 5.6 or less and a reduction rate of the acid amount A after a hydrothermal resistance test at 350 ° C. of 10% or less or a dehydrated product thereof is used. Method for producing alcohol. 2. An acid amount A having an average particle size of 1 μm or more and an acidity function Ho: −3.0 or less is 0.35 m.
mol / g, 50% or more of the acid amount A is H
o: Alcohol production by hydration of olefin consisting of niobic acid particles or dehydration product thereof, which has a strong acid amount B of −5.6 or less and an acid amount A reduction rate of 10% or less after a hydrothermal resistance test at 350 ° C. Catalyst. 3. A nitric acid particle or a dehydrated product thereof which is a solid acid catalyst component, wherein the niobium compound is dissolved or not dissolved in an alkaline aqueous solution having a pH of more than 11, and the niobium compound is acidified at a pH of 5 or less. The aqueous solution containing niobate particles having an average particle size of 1 μm or more obtained by gradually adding and mixing the aqueous solution with stirring so that the average pH drop rate of the mixed solution is 0.2 / min or less is 5.5 to 11. The method according to claim 1, which is prepared from niobate particles or dehydrated product thereof separated from the mixed solution of No. 0. 4. An acidic aqueous solution having a pH of 5 to 11.0 with respect to a mixed solution of niobic acid particles or a dehydrated product thereof which is a solid acid catalyst component and which contains niobic acid particles having an average particle size of 1 μm or more. And a step of adding and mixing
Mixing containing niobate particles having an average particle size of 1 μm or more obtained by alternately repeating the step of adding an alkaline aqueous solution of H while maintaining the pH of the mixed solution in the range of 5.5 to 11.0. The method according to claim 1, which is prepared from niobate particles separated from a liquid or a dehydrated product thereof. 5. A nitric acid particle or a dehydrated product thereof, which is a solid acid catalyst component, is an acidic aqueous solution having a pH of 5 or less with respect to a mixed solution of niobic acid particles having an average particle diameter of 1 μm or more and having a pH of 5.5 to 11.0. And a step of adding and mixing
The step of adding and mixing the alkaline aqueous solution of H is alternately repeated while maintaining the pH of the mixed solution in the range of 5.5 to 11.0, and at that time, a niobium compound is added to at least one of the alkaline aqueous solution and the acidic aqueous solution. PH 5. containing niobate particles having an average particle size of 1 μm or more obtained by dissolution.
The method according to claim 1, which is prepared from niobic acid particles separated from a mixed solution of 5 to 11.0 or a dehydrated product thereof.