JP2000247641A - Zirconium hydroxide and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce zirconium hydroxide by which an acidic solid substance having excellent solid acidity is obtained with good reproducibility and to provide the acidic solid substance. SOLUTION: The objective zirconium hydroxide has at least two absorption bands in the region of 300-1,700 cm-1 in the measurement of infrared ray absorption spectra. The method for producing the zirconium hydroxide is comprised of the first step of hydrolyzing an aqueous solution of soluble zirconium salt to prepare a slurry, the second step of adding a base to the slurry to form hydroxide and the third step of separating and recovering the hydroxide.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a novel zirconium hydroxide and a method for producing the same.

[0002]

2. Description of the Related Art In the chemical industry, many reactions requiring an acid catalyst such as an alkylation reaction, an acylation reaction, an esterification reaction and an isomerization reaction are known. Conventionally, sulfuric acid, hydrogen fluoride, phosphoric acid, aluminum chloride, p-toluenesulfonic acid and the like have been known as an acid catalyst used in this type of reaction.

[0003] However, these acid catalysts generally have the property of corroding metals. For this reason, expensive corrosion-resistant materials must be used for the reactor, or corrosion-resistant treatment must be performed on the reactor. In addition, it is difficult to separate and recover the acid catalyst from the reaction product after the reaction, and even if separation and recovery can be performed, waste acid treatment such as alkali washing is required. Also, it is very difficult to reuse the acid catalyst from a technical and cost standpoint.

[0004] Under such circumstances, many attempts have been made to use a solid acidic substance as an acid catalyst. As the solid acidic substance, for example, a hydroxide or hydrated oxide of Group IV metal represented by zirconium is brought into contact with an aqueous solution containing a sulfuric acid, and then calcined at 350 to 800 ° C. It has been reported that hydroxides exhibit higher acidity than 100% by mass sulfuric acid (Japanese Patent Publication No. 59-61).
No. 81, Japanese Patent Application Laid-Open No. 9-103681, Japanese Patent Application Laid-Open
1-263922, JP-A-61-153140, etc.). In general, it is known that the activity of these solid acidic substances increases as the solid acidity increases.

[0005]

However, even in these solid acidic substances, the solid acidity cannot be said to be sufficient, and there is still room for improvement. Also,
Further improvements in stability are needed.

Although many research reports have been made on the mechanism or principle of solid acid development in parallel with the development on an industrial scale, most of them have been reported as a composite of two or more metals or a metal element and a non-metal. It is being studied focusing on the effects of compounding with elements (Kazushi Arata, Petr
ochem, 19, 9, 733 (1996)), at present, little has been studied on the structural or chemical properties of zirconium hydroxide or hydrous zirconium hydroxide itself.
Therefore, even the properties required when these hydroxides or hydrated oxides (hydrated oxides) are used as solid acidic substances have not been elucidated chemically.

Accordingly, an object of the present invention is to produce zirconium hydroxide which can provide a solid acidic substance having excellent solid acidity with good reproducibility, and to provide the solid acidic substance.

[0008]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that zirconium hydroxide prepared through a specific step has a peculiar structure, and finally completed the present invention. Reached.

That is, the present invention relates to the following zirconium hydroxide and a method for producing the same.

[0010] 1. 13 in the infrared absorption spectrum measurement
Zirconium hydroxide having two or more infrared absorption bands at 00 to 1700 cm ^-1 .

2. Hydroxidation having a first step of preparing a slurry by hydrolyzing an aqueous solution of a soluble zirconium salt, a second step of adding a base to the slurry to form a hydroxide, and a third step of separating and recovering the hydroxide A method for producing zirconium.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on its embodiments. The zirconium hydroxide of the present invention also includes hydrous zirconium hydroxide. That is, zirconium hydroxide has the general formula ZrO (OH) ₂
· NH is a compound represented by the ₂ O (n> 0), hydrous zirconium oxide is a compound represented by the general formula _{ZrO 2 · nH 2 O (n} > 0), the present invention includes both.

The zirconium hydroxide of the present invention has an infrared absorption spectrum measurement of 2300 to 1700 cm ^-1 .
It has the above (preferably 3 or more) infrared absorption bands.

Further, the zirconium hydroxide of the present invention comprises 3
It is preferable to show an X-ray diffraction image belonging to a monoclinic system of zirconium oxide after heat treatment at 00 to 400 ° C. That is, the zirconium oxide obtained by heating the zirconium hydroxide of the present invention preferably contains a monoclinic system.

The above heat treatment temperature may be any as long as it shows an X-ray diffraction image belonging to the monoclinic zirconium oxide when the heat treatment is performed at any temperature within the above range. In the present invention, other X-ray diffraction images (peaks of other crystal phases) may be simultaneously expressed as long as an X-ray diffraction image belonging to a monoclinic system of zirconium oxide is shown.
In other words, other crystal phases may be contained together with the monoclinic system.

The specific surface area of the zirconium hydroxide of the present invention is not particularly limited, and can be appropriately set according to the use and purpose of the final product. For example, when used for a solid acid catalyst such as a solid acid catalyst or a solid acidic catalyst carrier, the BET specific surface area is preferably 200 m ² / g or more, particularly preferably 250 m ² / g or more. By employing such a specific surface area, a more excellent effect as a catalyst material can be exhibited. Therefore, as shown below, it can be suitably used as zirconium hydroxide for solid acidic compositions (particularly for catalysts, preferably for solid acid catalysts).

The zirconium hydroxide of the present invention comprises, for example, a first step of preparing a slurry by hydrolyzing an aqueous solution of a soluble zirconium salt, a second step of adding a base to the slurry to form a hydroxide, and It can be obtained by a production method having a third step of separating and recovering substances.

The soluble zirconium salt used in the first step is not particularly limited as long as it is soluble in water.
A product obtained by a known production method or a commercially available product can also be used. For example, nitrates such as zirconium oxynitrate, zirconium chloride, chlorides such as zirconium oxychloride,
An acetate such as zirconium acetate can be used.
In the present invention, among these, zirconium oxychloride is particularly preferred.

The concentration of the aqueous solution of the soluble zirconium salt may be appropriately set according to the kind (solubility) of the soluble zirconium salt to be used.
What is necessary is just 100 g.

The method of hydrolysis in the first step is not particularly limited as long as a slurry containing the hydrolyzate is produced. For example, it can be carried out by adding a hydrolyzing agent to the aqueous solution. Examples of the hydrolyzing agent include inorganic acids such as sulfuric acid, organic acids such as phthalic acid, inorganic acid salts such as ammonium sulfate and aluminum sulfate, and organic acid salts such as ammonium phthalate and sodium phthalate. The amount of the hydrolyzing agent added can be appropriately changed depending on the type of the hydrolyzing agent used, the type of the aqueous solution, and the like, but is generally sufficient to react with all the soluble zirconium salts in the aqueous solution to form a slurry. Any amount may be used, and a hydrolyzing agent in excess of the stoichiometric amount may be added.

Next, in the second step, a hydroxide is formed by adding a base to the slurry. The type of base used is not particularly limited, and for example, sodium hydroxide, potassium hydroxide, ammonia, sodium carbonate, ammonium carbonate, and the like can be used. The amount of the base to be added is not particularly limited as long as the hydroxide can be generated.
It may be adjusted so that H is 9 or more, preferably 12.5 or more.

Finally, as a third step, the hydroxide generated in the second step is separated and recovered. The method of separation and recovery may be in accordance with a known solid-liquid separation method. For example, filtration, centrifugation, decantation and the like can be used. As a result, the zirconium hydroxide of the present invention can be obtained as a so-called hydrous zirconium hydroxide (a zirconium hydroxide precursor). After separation and recovery, the obtained zirconium hydroxide can be washed with water as needed.

The obtained zirconium hydroxide may be dried if necessary. The drying may be performed by a known drying method, and may be either natural drying or heat drying. In particular, when the zirconium hydroxide of the present invention is used as a solid acid catalyst, it is preferable to heat and dry at 50 ° C or higher, preferably 100 to 130 ° C. The atmosphere in the case of heating and drying is not particularly limited, but in the present invention, it is preferable to perform the drying in a vacuum. By heating and drying in a vacuum, effects such as chemically preventing carbon dioxide from adsorbing in the atmosphere and shortening the drying time in terms of productivity can be obtained. After drying, zirconium hydroxide may be pulverized by a known method, if necessary.

In the case of producing a solid acidic composition from the zirconium hydroxide, for example, the zirconium hydroxide is treated with an aqueous solution containing at least one of sulfuric acid, tungstic acid and molybdic acid, and then calcined at 300 ° C. or more. Good.

As the sulfuric acid, tungstic acid and molybdic acid, those known per se or commercially available products may be used. The concentration of the aqueous solution can be appropriately set depending on the use of the final product, desired performance, and the like.
It may be about 2 mol / l, preferably 0.5 to 1 mol / l.

As a method of treating with the aqueous solution, for example, zirconium hydroxide may be dispersed (or immersed) in the aqueous solution. The amount of zirconium hydroxide dispersed in the aqueous solution can be appropriately determined according to the concentration of the aqueous solution, the amount of sulfuric acid to be supported, and the like.
About 100 g / liter, preferably 100-300 g /
It should be liter.

After the above treatment, solid-liquid separation or drying is performed by a known method, if necessary, followed by baking. The firing temperature is usually 300 ° C. or higher, preferably 500 to 800.
° C. The firing atmosphere is not particularly limited, and may be usually in the air. The firing time can be appropriately set according to the firing temperature and the like. Thereby, a solid acidic composition such as sulfuric acid-containing zirconia (sulfuric acid-supporting zirconia) is obtained.

The solid acidic composition of the present invention exhibits excellent solid acidity. In particular, the ammonia desorption start temperature is 125 ° C. or higher, and the ammonia adsorption amount is 4 mmol-N
It shows a characteristic of H ₃ / g or more. That is, the solid acidic composition of the present invention has a high solid acidity and a large amount of solid acid.

The solid acidic composition of the present invention can be used for the same applications as known solid acidic substances, and in particular, can be suitably used as a solid acid catalyst or a solid acidic carrier. When the composition of the present invention is used as a solid acid catalyst or a solid acidic catalyst carrier, it can be used according to a method similar to a known solid acid catalyst or a solid acidic catalyst carrier.

[0030]

The infrared absorption due to the metal-oxygen bond generally appears around 1000 to 2000 cm ^-1 . If the central metal and the oxygen bonded to it all have an equivalent relationship, there is only one infrared absorption band. Not observed. Conventional zirconium hydroxide also takes a crystal system called a metastable tetragon when heated. And in this metastable tetragon,
There are two types of metal-oxygen bonds, and very similar infrared absorption bands (ie, substantially one infrared absorption band) are observed.

On the other hand, when the zirconium hydroxide of the present invention was similarly measured for its infrared absorption spectrum,
Two or more infrared absorption bands are shown at ^{0 to} 1700 cm ^-1 . For example, samples 1 to 1 prepared in Example 1 shown below
2 shows three infrared absorption bands at 1300 to 1700 cm ⁻¹ , which indicates that the compound has three or more unequal metal-oxygen bonds. That is, the zirconium hydroxide of the present invention generally includes a crystal system belonging to a monoclinic system having an oxygen coordination number of 7, and this crystal system has oxygen defects. Since such oxygen deficiency is mainly a place where solid acidity appears, the zirconium hydroxide of the present invention exhibits high solid acidity. As a result, the zirconium hydroxide of the present invention can exhibit an excellent effect as a solid acid catalyst or a solid acidic catalyst carrier.

In the present invention, particularly, 300 to 400 ° C.
Zirconium hydroxide, which shows an X-ray diffraction image belonging to the monoclinic system of zirconium oxide after the heat treatment, can maintain the monoclinic system even after the heat treatment, so that a stable catalytic acidity (solid acidity) with good reproducibility is obtained. be able to.

[0033]

According to the production method of the present invention, zirconium hydroxide having a crystal system different from that of the conventional zirconium hydroxide can be obtained. According to the zirconium hydroxide, a solid acidic substance having excellent solid acidity can be provided with good reproducibility.

The solid acidic composition obtained from the above zirconium hydroxide is particularly useful as a solid acid catalyst or a solid acidic catalyst carrier because of its high solid acid strength and large amount of solid acid. Therefore, it can be suitably used in, for example, an alkylation reaction, an acylation reaction, an esterification reaction, an isomerization reaction, and other reactions that generally require an acid catalyst.

[0035]

The following examples are provided to further clarify the features of the present invention.

Example 1 (1) Preparation of Zirconium Hydroxide (Samples 1 and 2 and Comparative Sample 1)
Hydrolysis was performed with 1000 g of 7% by weight phthalic acid to obtain a slurry of zirconium dicarboxylate. Next, a sodium hydroxide solution was added to the slurry until the pH reached 13, and a hydroxide precipitate was formed. After the precipitate was filtered and washed with water, the solid content was recovered to obtain a zirconium hydroxide precursor. The precursor was dried in a vacuum dryer at 120 ° C. for 24 hours to obtain zirconium hydroxide (sample 1).

10% by weight zirconium oxychloride solution 1
000 g was hydrolyzed with 60 g of sodium sulfate to obtain a slurry of basic zirconium sulfate. Next, a sodium hydroxide solution was added to the slurry until the pH reached 13, and a hydroxide precipitate was formed. After the precipitate was filtered and washed with water, the solid content was recovered to obtain a zirconium hydroxide precursor. The precursor was dried at 120 ° C. for 24 hours in a vacuum dryer to obtain zirconium hydroxide (Sample 2).

Aqueous ammonia was added to 1000 g of a 10% by weight aqueous solution of zirconium oxychloride until the pH reached 10.1 to precipitate hydroxide. Next, the precipitate was filtered and washed with water to obtain a zirconium hydroxide precursor.
This precursor was dried in a dryer at 120 ° C. for 24 hours to obtain zirconium hydroxide (Comparative Sample 1).
(2) Preparation of Sulfuric Acid-Containing Zirconium Oxide (Solid Acidic Composition) The zirconium hydroxide of Sample 1 was dispersed in a 10% by weight ammonium sulfate solution, filtered, and then 600 ° C. in the atmosphere.
And the corresponding sulfuric acid-containing zirconium oxide (sample 3) was obtained. By treating in the same manner, zirconium oxide containing sulfuric acid from sample 2 (sample 4) and zirconium oxide containing sulfuric acid from comparative sample 1 (comparative sample 2) were obtained.

Test Example 1 Evaluation of zirconium hydroxide Samples 1 and 2 prepared in Example 1 and zirconium hydroxide of Comparative Sample 1 were measured for infrared absorption spectrum,
The line diffraction analysis and the measurement of the specific surface area were respectively performed.

The infrared absorption spectrum was measured by a microscopic transmission method using an infrared absorption spectrum measuring apparatus (manufactured by Herschel; FT / IR-420). The X-ray diffraction analysis was measured using an X-ray diffractometer (Rigaku; RAD-2C). The specific surface area is measured using a specific surface area meter (manufactured by MICROMERITICS; FL)
OWSORB-II) was measured by the BET method.

Table 1 shows the measurement results of the specific surface area and the water content. FIG. 1 shows the measurement results of the infrared absorption spectrum. Also,
FIG. 2 shows the results of X-ray diffraction analysis after heating each zirconium hydroxide at 300 ° C. FIG. 2 shows that Samples 1 and 2 have monoclinic peaks at 28.2 ° and 31.5 °, respectively.

[0042]

[Table 1]

Test Example 2 Evaluation of Sulfuric Acid-Containing Zirconium Oxide The samples 3 to 4 prepared in Example 1 and the sulfuric acid-containing zirconium oxide of Comparative Sample 2 were subjected to infrared absorption spectrum measurement, X-ray diffraction analysis, ammonia adsorption amount and ammonia The desorption starting temperature was measured.

The results of infrared absorption spectrum measurement and X-ray diffraction analysis were measured in the same manner as in the case of zirconium hydroxide. In addition, the ammonia adsorption amount was measured using a TPD measuring device (manufactured by Nippon Bell; multitask TPD (TPD-1-AT)).
Was measured by a temperature programmed desorption method.

FIG. 3 shows the measurement results of the infrared absorption spectrum. The result of the X-ray diffraction analysis is shown in FIG. In FIG. 4, each sample has a peak at 30.2 °, and the sulfate group (S
It can be seen that O ₄ ) forms a metastable tetragonal system. Table 2 shows the ammonia adsorption amount and the ammonia desorption start temperature of these samples.

[0046]

[Table 2]

From the results in Table 2, it can be seen that Sample 3 and Sample 4 have a larger ammonia adsorption amount than Comparative Sample 2;
It turns out that the solid acid amount is large. In addition, since Sample 3 and Sample 4 have a higher ammonia desorption start temperature than Comparative Sample 2, it can be seen that the solid acidity is higher.

[Brief description of the drawings]

FIG. 1 is a view showing a measurement result of an infrared absorption spectrum of each zirconium hydroxide prepared in Example 1 (1).

FIG. 2 is a view showing an X-ray diffraction measurement result of each zirconium hydroxide prepared in Example 1 (1).

FIG. 3 is a view showing a measurement result of an infrared absorption spectrum of each sulfuric acid-containing zirconium oxide prepared in Example 1 (2).

FIG. 4 is a diagram showing an X-ray diffraction measurement result of each sulfuric acid-containing zirconium oxide prepared in Example 1 (2).

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Kimio Ouchi 1- 6-38 Hirabayashiminami, Suminoe-ku, Osaka-shi, Osaka F-term (reference) 4G048 AA02 AB05 AC08 AD04 AD06 AE05 4G069 AA01 AA05 AA08 AA09 AA12 AA14 BA45A BB05A BB05B BC51A BC51B BC59A BC60A CB62 CB75 DA05 EC03X EC03Y EC22X EC22Y FB30 FB49 FC04 FC07 FC09

Claims (12)

[Claims] 1. The method according to claim 1, wherein the infrared absorption spectrum is measured at 1300.
Zirconium hydroxide having two or more infrared absorption bands at １1700 cm ⁻¹ . 2. After the heat treatment at 300 to 400 ° C.,
The zirconium hydroxide according to claim 1, which shows an X-ray diffraction image belonging to a monoclinic system of zirconium oxide. 3. The zirconium hydroxide according to claim 1, having a BET specific surface area of 200 m ² / g or more. 4. A first step of preparing a slurry by hydrolyzing an aqueous solution of a soluble zirconium salt, a second step of adding a base to the slurry to form a hydroxide, and a third step of separating and collecting the hydroxide. A method for producing zirconium hydroxide having a step. 5. The method according to claim 4, wherein in the second step, a base is added so that the slurry pH becomes 9 or more. 6. The method according to claim 4, further comprising a fourth step of heat-treating the hydroxide at 50 ° C. or higher. 7. The method according to claim 1, wherein the zirconium hydroxide is treated with an aqueous solution containing at least one of sulfuric acid, tungstic acid and molybdic acid, and then calcined at 300 ° C. or more. A method for producing a solid acidic composition. 8. A solid acidic composition obtained by the method according to claim 7. 9. An ammonia desorption starting temperature of 125 ° C. or higher and an ammonia adsorption amount of 4 mmol-NH ₃ / g
The solid acidic composition according to claim 8, which is the above. 10. A solid acid catalyst or a solid acidic catalyst carrier comprising the composition according to claim 9. 11. An ammonia desorption starting temperature of 125 ° C. or more and an ammonia adsorption amount of 4 mmol-NH ₃ /
g or more, a zirconia-based solid acidic composition. 12. A solid acid catalyst or a solid acidic catalyst carrier comprising the composition according to claim 11.