JP3004291B2 - Method for producing crystalline layered phosphoric acid compound - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a crystalline layered phosphate compound. More specifically, the present invention uses a tetravalent metal compound and a phosphoric acid source as raw materials, mixes the two, and performs a heating reaction. The present invention relates to a method for producing a crystalline layered phosphoric acid compound.

The crystalline layered phosphoric acid compound obtained according to the present invention has a large solid acidity and a large interlayer distance, and thus has various cations (such as Na ⁺ , Ag ⁺ , Cs ⁺ ), basic substances, and organic substances. It has high reactivity with amines and the like, and can be applied to, for example, adsorbents, inorganic ion exchangers, and intercalation.

[Conventional technology]

Conventionally, as a method for producing a crystalline layered phosphoric acid compound,
The reflux method, the fluoride complex method, and the like have been adopted (for example, “Application of Inorganic Polymer-Hybrid Polymer”, published by CMC, pp. 278-279).

The above-mentioned reflux method is a method for producing a crystalline layered phosphoric acid compound by refluxing an amorphous phosphate in concentrated phosphoric acid for 24 to 100 hours. Excessive use and a long time for the reaction have caused a problem of lack of economic efficiency industrially.

Further, the above fluorinated complex method has a problem of lack of safety because toxic hydrogen fluoride is used.

In the case of crystalline layered zirconium phosphate, a production method by a hydrothermal synthesis method has been proposed (Japanese Patent Application Laid-Open No.
226807), hydrothermal synthesis requires high temperature and pressure,
When employed as a production method on an industrial scale, it is necessary to use a device that can withstand a strong acid such as phosphoric acid under high pressure, and there have been various problems in terms of material of the device.

[Problems to be solved by the invention]

As described above, the conventional method for producing a crystalline layered phosphoric acid compound has the following disadvantages. (1) Lack of economy due to use of a large excess of concentrated phosphoric acid (2) Long reaction time (3) Poisonous Since hydrogen fluoride was used, there were problems such as lack of safety. Also, in the conventional manufacturing method,
In addition to the above-mentioned problems in the process, there is also a problem that a compound having an extremely large interlayer distance (for example, Ce (HPO ₄ ) ₂ .2H ₂ O) cannot be obtained.

Therefore, an object of the present invention is to solve these problems and to provide a method capable of producing a crystalline layered phosphate compound in a short time and with high efficiency by a reaction under normal pressure.

[Means for solving the problem]

The present invention relates to the production of a crystalline layered phosphoric acid compound,
The above object has been achieved by blowing steam into the reaction system when mixing and heating a tetravalent metal compound as a raw material and a phosphoric acid source.

That is, the crystalline layered phosphoric acid compound is a compound having water of crystallization, but when the tetravalent metal compound reacts with the phosphoric acid source, water vapor is introduced from the outside, and the tetravalent metal compound and the phosphoric acid are reacted in the presence of the water vapor. When the reaction with the acid source is carried out under normal pressure, the reaction product tends to have water of crystallization, and the desired crystalline layered phosphoric acid compound can be obtained in a short time.
Further, since the reaction proceeds easily, a crystalline layered phosphoric acid compound can be obtained without using a large excess of a phosphoric acid source, and the efficiency is improved.

For example, in the conventional reflux method, a reaction time of about 24 to 100 hours (generally about 48 hours) was required. However, according to the present invention, the desired crystalline layered phosphorous was obtained in a reaction time of about 3 to 5 hours. An acid compound is obtained. In the reflux method, concentrated phosphoric acid is converted to a molar excess of P ₂ O ₅ / MO ₂ (where M is a tetravalent metal element and MO ₂ is an oxide of a tetravalent metal element). According to the present invention, the molar ratio of P ₂ O ₅ / MO ₂ to the tetravalent metal compound is The desired crystalline layered phosphoric acid compound can be obtained by using a phosphate source at most about 2.5 times.

In the case of crystalline layered cerium phosphate, the interlayer distance represented by the chemical formula Ce (HPO ₄ ) ₂ · 1.33H ₂ O is 15.
Although only 9 本 (1.59 nm) was obtained, according to the present invention, the introduction of steam promotes the reaction by making the reaction product easy to have water of crystallization.
(HPO ₄₎ an interlayer distance indicated by 2 _· 2H ₂ O is so large crystalline layered cerium phosphate of 18.0Å is obtained.

However, when steam is not introduced into the reaction system, 3
If the reaction time is as short as about 5 hours, the reaction does not proceed at all, or only the desired crystalline layered phosphoric acid compound can be obtained.

In the practice of the present invention, as the tetravalent metal compound, an oxide of at least one metal element selected from the group consisting of Group 4 metal elements such as titanium, zirconium, hafnium, germanium, tin, lead and cerium; Oxides, short acid salts, sulfates, nitrates, chlorides, etc. are used. Phosphoric acid sources include phosphoric acid (for example, commercially available 85% phosphoric acid), sodium phosphate, potassium phosphate, and ammonium phosphate And the like.

Then, two different reaction modes can be adopted depending on the type of the tetravalent metal compound used.

One is that when the tetravalent metal compound is a Group 4 metal element or an oxide, hydroxide, carbonate of cerium or a mixture thereof, phosphoric acid is used as a phosphoric acid source, and Mix with a phosphoric acid source, blow steam,
In this method, both are heated and reacted under normal pressure in the presence of steam.

Another is that when the tetravalent metal compound is a water-soluble salt of a Group 4 metal element or cerium, for example, sulfate, nitrate, chloride or a mixture thereof, phosphoric acid or water-soluble phosphoric acid is used as a phosphoric acid source. Using salts such as sodium phosphate, potassium phosphate, ammonium phosphate,
An aqueous solution of the above tetravalent metal compound and an aqueous solution of a phosphoric acid source are heated at room temperature or under the boiling temperature of water,
A method in which a gel-like precipitate is generated by stirring and mixing, and after filtration, steam is blown into the gel to precipitate a tetravalent metal compound and a phosphoric acid source under a normal pressure in the presence of steam to cause a heat reaction. It is.

In any case, the molar ratio of the raw materials during the reaction in the steam atmosphere, that is, the molar ratio between the tetravalent metal compound and the phosphoric acid source is P ₂ O ₅ / MO ₂ (where M is a tetravalent metal Element
MO ₂ is an oxide of a tetravalent metal element), and is preferably in the range of 0.5 to 2.5 in terms of the molar ratio. That is, when the molar ratio is less than 0.5, the amount of the unreacted tetravalent metal compound remaining as a raw material increases, and when the molar ratio exceeds 2.5, excess phosphoric acid remains, which is uneconomical. A more desirable molar ratio is in the range of 1.0 to 2.0.

The amount of water vapor is not particularly limited, but usually,
This is performed by blowing steam from the outside into the head space above the reaction mixture in the reaction vessel.

In blowing steam into the reaction system, it is desirable to heat the steam to a temperature substantially equal to the reaction temperature so that the reaction temperature does not decrease.

The blowing of steam is not always necessary at the very early stage of the reaction, but it is necessary to blow steam after free moisture evaporates from the reaction system. Of course,
During the heating reaction, steam may be constantly blown into the reaction system.

As the crystalline layered phosphoric acid compound, for example, the following compounds have been known.

_{Ti (HPO 4) 2 · H} 2 O ( interlayer _{distance; 7.6Å) Ti (HPO 4)} 2 · 2H 2 O ( interlayer _{distance: 11.6Å) Zr (HPO 4)} 2 · H 2 O ( interlayer distance: 7.6 Å _{) Zr (HPO 4) 2 ·} 2H 2 O ( interlayer _{distance: 12.2Å) Hf (HPO 4)} 2 · H 2 O ( interlayer _{distance: 7.6Å) Sn (HPO 4)} 2 · 2H 2 O ( interlayer distance: 7.8 _{Å) Pb (HPO 4) 2} · H 2 O ( interlayer _{distance: 7.8Å) Ce (HPO 4)} 2 · 1.33H 2 O ( interlayer distance: 15.9Å) According to the present invention, as well, these crystalline layered The phosphoric acid compound can be produced in a shorter time and with higher efficiency than the conventional method.

Furthermore, according to the present invention, the crystalline layered cerium phosphate having a large interlayer distance, which cannot be produced by the conventional method, that is, the interlayer distance having two molecules of crystal water represented by the following chemical formula is 18.0Å. Can be produced.

Ce (HPO ₄ ) ₂ · 2H ₂ O (interlayer distance: 18.0 よ り) According to the present invention, Ce (HPO ₄ ) ₂ · 2H ₂ O
Can also be manufactured in a short time and with high efficiency, like other products.

As described above, these crystalline layered phosphoric acid compounds exhibit large solid acidity and have a large interlayer distance. Therefore, these crystalline layered phosphoric acid compounds are used for adsorbents, inorganic ion exchangers, intercalation, etc. can do. Especially Ce (HPO ₄ ) ₂・ 2H ₂ O has a large interlayer distance,
For example, when used as an adsorbent, it can be used as an adsorbent having excellent properties such as adsorbing a substance having a large molecular weight, or as an intercalator.

〔Example〕

Next, the present invention will be described specifically with reference to examples.
The present invention is not limited to only these examples.

Example 1 19.5 g of commercially available cerium oxide (reagent grade 99% CeO ₂ )
31.2 g of 5% phosphoric acid (molar ratio of P ₂ O ₅ / CeO ₂ of 1.2) was thoroughly stirred and mixed in a porcelain crucible.
The mixture was placed in an electric furnace set to 0 ° C., steam heated to 180 ° C. was blown, and cerium oxide and phosphoric acid were reacted at 180 ° C. under normal pressure for 4 hours in the presence of steam. The reaction product was pale yellow. The reaction product was washed with water and air-dried. In any of the following examples, the reaction is carried out under normal pressure.

The X-ray diffraction profile of the material after air drying is shown in FIG.

As shown in FIG. 1, the X-ray diffraction profile of the obtained substance has a strong peak at the lowest angle near 5 °. From the measurement results of X-ray diffraction and the results of elemental analysis,
The obtained substance is a crystalline layered cerium phosphate [Ce (HPO ₄ )
Was found to be ₂ · 2H ₂ O].

Example 2 Potassium hydroxide _{[Ce (OH) 4 .3 / 2H} 2 O ] and 26.5 g, 85%
31.2 g of phosphoric acid (1.2 in terms of the molar ratio of P ₂ O ₅ / CeO ₂ ) is mixed well in a porcelain crucible with stirring, and the resulting mixture is placed in an electric furnace set at 200 ° C. with the crucible. Then, steam heated to 200 ° C. was blown, and cerium hydroxide and phosphoric acid were reacted at 200 ° C. for 4 hours in the presence of steam. The reaction product was pale yellow. After washing the reaction product with water,
Dried at 180 ° C.

The X-ray diffraction profile of the material immediately after drying is shown in FIG.

As shown in FIG. 2, the X-ray diffraction profile of the obtained substance has a strong peak slightly over 5 °, and this X-ray diffraction profile is based on the existing crystalline layered phosphate compound [Ce ( HPO ₄₎ from 2 _· 0.33H ₂ O] that matches the X-ray diffraction profile of the resulting material is found to be crystalline layered phosphate compound _{[Ce (HPO 4) 2 · 0.33H} 2 O ] did. This substance is converted into a substance having the same X-ray diffraction profile as that shown in FIG. 1 by being left in the air or by adding a small amount of water, and the crystalline layered cerium phosphate [Ce (HPO _{4) 2 ·} 2H 2 O] is that obtained was found.

Example 3 Commercially available 15.9 g of zirconium hydroxide [Zr (OH) ₄ ] (primary reagent) and 34.6 g of 85% phosphoric acid (1.5 in terms of the molar ratio of P ₂ O ₅ / ZrO ₂ ) were used. The mixture was mixed in a porcelain crucible in the same manner as in Example 1, and the resulting mixture was placed in an electric furnace set at 190 ° C. and steam heated to 190 ° C. was blown therein, and zirconium hydroxide and phosphorus were added in the presence of steam. With acid
The reaction was performed at 190 ° C. for 5 hours. The reaction product was white. The reaction product was washed with water and air-dried.

The X-ray diffraction profile of the material after air drying is shown in FIG.

As shown in FIG. 3, the X-ray diffraction profile of the obtained substance slightly exceeded 10 °, and had strong peaks around 20 ° and 25 °.
Existing crystalline layered zirconium phosphate [Zr (HPO ₄ ) ₂・
H ₂ O], the obtained substance was a crystalline layered zirconium phosphate [Zr (HP
O ₄ ) ₂ · H ₂ O].

Example 4 11.6 g of titanium hydroxide [Ti (OH) ₄ ] and 34% of 85% phosphoric acid
Example 6 was 6 g (1.5 in terms of the molar ratio of P ₂ O ₅ / TiO ₂ ).
Mix in a porcelain crucible in the same manner as above, put the resulting mixture together with the crucible into an electric furnace set at 210 ° C, blow steam heated to 210 ° C, and mix titanium hydroxide and phosphoric acid in the presence of steam. Was reacted at 210 ° C. for 5 hours. The reaction product was white. The reaction product was washed with water and dried at 50 ° C.

When the X-ray diffraction profile of the dried substance was examined, the existing crystalline layered titanium phosphate [Ti (HPO ₄ ) ₂ .H ₂
O], the obtained substance was a crystalline layered titanium phosphate [Ti (HPO ₄ ) ₂ .H ₂
O].

Example 5 23.5 g of a water-soluble zirconium salt, ZrOCl _{2, was} mixed with pure water 500
Then, 46.1 g of 85% phosphoric acid (1.5 in terms of a molar ratio of P ₂ O ₅ / ZrO ₂ ) was gradually added dropwise thereto with stirring.
As a result, a white gel-like precipitate was obtained. After centrifugation, the mixture was put in a porcelain crucible, and 85% phosphoric acid was added.
After mixing, the whole crucible was placed in an electric furnace set at 190 ° C., steam heated to 190 ° C. was blown, and a reaction was performed at 190 ° C. for 4 hours in the presence of steam. The reaction product was washed with water and air-dried.

When the X-ray diffraction profile of the air-dried material was examined and found to be consistent with FIG. 3 of Example 3, the obtained material was crystalline layered zirconium phosphate [Zr (HPO ₄ ) ₂ .H _2.
O].

Example 6 43.3 g of commercially available tin chloride (SnCl ₄ ) (first grade reagent) was added to 50 ml of pure water.
Dissolve in 0 ml and separately add sodium phosphate (Na ₂ HPO ₄
143.2 g of (12H ₂ O) (primary reagent) was dissolved in 500 ml of pure water.

While stirring the tin chloride solution, the sodium phosphate aqueous solution was gradually dropped into the tin chloride solution to obtain a precipitate.
After filtration, put the precipitate in a porcelain crucible and further add 85% phosphoric acid
After adding 11.3 g and stirring, the whole crucible was put into an electric furnace set to a temperature of 200 ° C., steam heated to 200 ° C. was blown, and the mixture was reacted at 200 ° C. for 4 hours in the presence of steam. P ₂ of tin chloride and sodium phosphate and phosphoric acid used
The molar ratio calculated as O ₅ / SnO ₂ was 1.5.

 The reaction product was washed with water and air-dried.

When the X-ray diffraction profile of the air-dried material was examined, the existing crystalline layered tin phosphate [Sn (HPO ₄ ) ₂ · H
₂ O], the obtained substance was a crystalline layered tin phosphate [Sn (HPO ₄ ) ₂ · H
₂ O].

Comparative Example 1 In Example 1, 18 was introduced without introducing steam from outside.
Heat at 0 ° C. for 4 hours.

The mixture after heating was almost white. The mixture was washed with water and air-dried.

The X-ray diffraction profile of the air-dried substance showed only a peak of only cerium oxide (CeO ₂ ) as a raw material, and it was found that cerium oxide and phosphoric acid did not react at all.

Comparative Example 2 In Example 3, 22 was introduced without introducing steam from outside.
Heat at 0 ° C. for 5 hours.

 After the heating, the reaction product was washed with water and air-dried.

The X-ray diffraction profile of the obtained substance shows only the peak of zirconium pyrophosphate [Zr ₂ P ₂ O ₇ ], and the desired crystalline layered zirconium phosphate [Zr (HPO ₄ ) ₂ .H _2]
O] was not obtained at all.

〔The invention's effect〕

As described above, in the present invention, by heating and reacting a tetravalent metal compound and a phosphoric acid source in the presence of water vapor, the reaction under normal pressure allows the crystalline layered phosphoric acid to be produced in a short time and with high efficiency. Compounds can now be produced.

[Brief description of the drawings]

FIG. 1 is an X-ray diffraction profile of the crystalline layered cerium phosphate [Ce (HPO ₄ ) ₂ .2H ₂ O] obtained in Example 1. FIG. 2 is an X-ray diffraction profile of the crystalline layered cerium phosphate [Ce (HPO ₄ ) ₂ .0.33H ₂ O] obtained in Example 2. FIG. 3 shows the X of the crystalline layered zirconium phosphate [Zr (HPO ₄ ) ₂ .H ₂ O] obtained in Example 3.
It is a line diffraction profile.

Continuation of front page (56) References JP-A-62-226807 (JP, A) JP-A-1-119507 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C01B 25 / 37

Claims (4)

(57) [Claims] In the step of mixing and heating a tetravalent metal compound and a phosphoric acid source, steam is blown, and the tetravalent metal compound and the phosphoric acid source are reacted under normal pressure in the presence of steam. A method for producing a crystalline layered phosphoric acid compound, comprising: 2. The mixing ratio between a tetravalent metal compound and a phosphoric acid source is as follows:
The molar ratio of P ₂ O ₅ / MO ₂ (where M is a tetravalent metal element and MO ₂ is an oxide of the tetravalent metal element) is 0.5 to 2.5
2. The method for producing a crystalline layered phosphoric acid compound according to claim 1, wherein the mixture is mixed so that the heating temperature is 100 ° C. to 300 ° C., and steam is blown. 3. The phosphoric acid source, wherein the tetravalent metal compound is an oxide, hydroxide, carbonate or a mixture thereof of at least one metal element selected from the group consisting of group 4 metal elements and cerium. The method for producing a crystalline layered phosphoric acid compound according to claim 2, wherein is phosphoric acid. 4. The tetravalent metal compound is a water-soluble salt of at least one metal element selected from the group consisting of group 4 metal elements and cerium, and the phosphate source is phosphoric acid or a water-soluble phosphate. The method for producing a crystalline layered phosphoric acid compound according to claim 2, wherein a heating reaction is performed after a gel is formed when the tetravalent metal compound and the phosphoric acid source are mixed.