JPS61146704A - Production of calcium-phosphorus type apatite - Google Patents

Abstract

PURPOSE:To produce the titled apatite by a simple method by spraying a starting material soln. prepd. by dissolving a specified Ca compound and the org. compound of P on a heated zone to cause the thermal decomposition. CONSTITUTION:One or more kinds of Ca compounds selected among Ca(NO3)2, CaCl2 and CaBr2 and the org. compound of P such as (CH3O)3P are dissolved in a combustible org. solvent having compatibility with water such as methanol in 1.25-1.75 molar ratio of Ca/P to prepare a starting material soln. having a uniform composition. A mixed solvent consisting of the org. solvent and water may be used in place of the org. solvent, and NH4Cl and/or NH4Br is further dissolved as required. The starting material soln. is sprayed on the heated zone or a flame at 700-1,500 deg.C to cause the thermal decomposition and the resulting product is captured by a cyclone or the like and heat treated at a desired temp., as necessary.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing calcium-phosphorus anotite.

Calcium-phosphorus apatite has unique performance as an adsorbent for biopolymers, fluoride ions, heavy metal ions, etc., and in recent years, it has been used for the separation of proteins, enzymes, etc. by utilizing its biocompatibility. It is considered to be useful as a filler for chromatography, and is also attracting attention as a bioceramic material for artificial bones and teeth.

Conventionally, many methods have been known for producing apatite, and the following methods are exemplified if broadly classified.

(1) A method using a solid diffusion reaction called a dry synthesis method.

(2) A method based on a reaction under high pressure called hydrothermal synthesis. This method is mainly used for the purpose of obtaining large crystals.

(3) Direct precipitation using aqueous ions, called a wet synthesis method.

However, the dry synthesis method (1) requires reaction at high temperatures for a long time, which consumes a lot of energy, and because it is a solid-solid reaction, it is difficult to achieve uniform composition.
There is a problem with this. Furthermore, the hydrothermal synthesis method (2) involves problems such as expensive equipment and complicated operations because the reaction is carried out at high pressure. In the wet synthesis method (3),
The apatite precipitate produced by the reaction must be separated from each other, washed and dried, and many steps are required, resulting in complicated operations.

The present inventors have completed the present invention as a result of repeated research on a method for producing calcium-phosphorus apatite using a simple operation that eliminates the drawbacks of the above-mentioned prior art and requires fewer steps. reached.

That is, the present invention provides a novel method for producing calcium-phosphorus apatite.

In the method of the present invention, as a starting material, a flammable organic solvent that is compatible with water or a flammable organic solvent that is compatible with water is mixed with water in order to achieve uniform mixing of raw materials at the atomic and molecular level. It uses a raw material solution with a uniform composition dissolved in a solvent, and one of its characteristics is that no precipitate is generated due to mixing.

Up to now, a number of wet synthesis methods for apatite have been proposed, but the idea common to these conventional wet synthesis methods is, for example, that a calcium salt aqueous solution and a phosphorus aqueous solution are mixed at a pH of 90 to 100°C. As shown in the example of the method of forming a precipitate by mixing in a decarboxylation atmosphere while maintaining the temperature near 8, apatite is directly formed as a precipitate, and then separated and recovered from an aqueous solution by operations such as filtration. Therefore, the calcium compounds and phosphorus compounds used in conventional wet synthesis methods include, for example, Ca(NOs)2,
CaCl2, Ca(OH)2, CaF2, H3PO4,
CaHFO4・2H20, (NH4)2HP0,1, N
Inorganic compounds of calcium and phosphorus have been used, such as H4H2PO, KH2PO4, Na2HPO4.

By the way, according to such conventional methods, the process of mixing a calcium salt water bath solution and a phosphorus aqueous solution to generate a precipitate through a direct reaction of ions and crystallizing it into apatite depends on the type and concentration of the raw salt and the mixing procedure. and mixing speed, p
It is difficult to obtain a precipitate with the exact composition as it is difficult to obtain a precipitate with the exact composition as the results vary depending on many factors such as H adjustment, the molar ratio of calcium and phosphorus (Ca/P), and the physicochemical properties of the powder produced. It was extremely difficult to control with good reproducibility. In addition, there were many drawbacks, such as requiring multiple steps such as filtration, washing, drying, and pulverization of the precipitate, as well as multiple devices, and requiring skill to operate them.

In contrast to such conventional methods, the technical feature of the present method Q is that in order to solve the difficulties in precipitation formation and crystallization processes in the conventional wet synthesis method, a flammable organic solvent compatible with water or a flammable organic solvent compatible with water is used. Using a mixed solvent of a soluble flammable organic solvent and water, dissolve a soluble inorganic calcium compound and an organic phosphorus compound in these solvents to prepare a G solution with a uniform composition that does not cause precipitation. is used as a raw material solution.

In the method of the present invention, in order to maintain the uniformity of the composition of this raw material solution all the way to the product, the volume in which the components in the solution are segregated is made extremely fine by the spray pyrolysis method, and the solvent evaporates. , the combustion is rapid and the droplets are
This was achieved by minimizing the segregation of components within the interior.

By the method of the present invention, the synthesis reaction can be completed in an extremely short time of just a few seconds or less, compared to the conventional technology that requires a long time to synthesize apatite. The special effect is that powder can be obtained directly without the need for all the complicated steps.

Furthermore, the method of the present invention has the advantage that apatite containing halogens such as chlorine and bromine can be easily synthesized. For example, chlorapatite has conventionally been synthesized only by high-temperature solid phase reaction or pressurized hydrothermal reaction, and not by normal pressure wet method, but in the method of the present invention, chlorine-containing raw materials such as CaCl2.2H20 and NH4ct are By using it, chlorapatite and solid solution apatite of chlorapatite and hydroxyapatite can be easily synthesized. Regarding bromine apatite and bromine solid solution apatite, CaBr2.2H20 and NH4Br
It can be implemented using, for example.

The powder produced by the spray pyrolysis reaction according to the method of the present invention is usually obtained as a hollow spherical fine powder, and depending on the type and combination of raw materials and the spray pyrolysis conditions, it may be amorphous, apatite crystal, etc. There are various cases, such as those containing both a crystalline phase and an amorphous phase, and those containing free-formed CaO and other by-products in addition to apatite, but in all cases, the specific surface area is It is a powder with high reactivity.Depending on the use and purpose, it may be preferable to use a powder with high reactivity. In some cases, it may be desirable to reduce or eliminate unreacted components and by-products.In that case, the powder produced by the spray pyrolysis reaction may be further treated in various atmospheres without decomposing the apatite. The above-mentioned physical properties can be controlled by heat treatment at a desired temperature within a stable temperature range.For example, for hydroxyapatite, heating at a desired temperature of 1400°C or less in an air atmosphere is possible. By processing, desired physical properties can be obtained.

For example, with regard to chlorapatite, by selecting the preparation conditions of the raw material solution and the spray pyrolysis conditions, when the spray pyrolysis product obtained is heated, approximately 500 to 1
In the temperature range of 000°C, calcium chloride phosphate (Ca
It is also possible to obtain a product which changes into 2PO4C1) and changes back into chlorapatite at high temperatures of 100° 0°C or higher. Therefore, in this case as well, chloroapatite can be obtained by heat treatment by selecting appropriate temperature conditions.

Regarding calcium chloride phosphate, the following facts can be found from the above facts. That is, in preparing the above-mentioned raw material solution of the method of the present invention, a soluble phosphorus organic compound and calcium chloride are used, their concentrations in the solution are appropriately selected, and the raw material solution is subjected to the above-mentioned spray pyrolysis treatment. Calcium chloride phosphate can be produced by then performing heat treatment at 500 to 1000°C.

In addition, when the apatite produced by the method of the present invention contains free produced CaO etc., if it is desirable to sufficiently remove them for the use of the target substance, a well-known method, For example, pure apatite can be obtained by extraction and removal using an aqueous ammonium chloride solution.

A more specific explanation of the method of the present invention is as follows. In the method of the present invention, first, a soluble phosphorus organic compound, calcium nitrate, calcium chloride, and One or two calcium compounds selected from calcium chloride and, if necessary, one selected from ammonium chloride and ammonium bromide are added, mixed, and dissolved to produce a homogeneous solution. A raw material solution with a specific composition is prepared, but the order in which these raw materials are mixed is not necessarily specified, and may be mixed in any order as long as it does not cause precipitation. . The time required for mixing will vary depending on the raw materials selected. When mixing, it is preferable to stir until a sufficiently uniform solution is obtained. Next, the solution prepared in this manner is sprayed by a known spraying method using a pressurized nozzle or a rotating disk into a heating zone preheated to 700 to 1500°C in a flame such as a gas burner or in a gas furnace or electric furnace. In a very short time of several seconds or less, the solvent in the solution is evaporated and burned into fine droplets, usually several tens of microns or less, and the solute is solidified and a thermal decomposition reaction takes place. The product is usually a hollow spherical fine powder and can be collected using a cyclone or the like.

Furthermore, if necessary, the powder produced by the spray pyrolysis reaction is heated in various atmospheres such as air, air with water vapor added, and an inert atmosphere at a desired temperature within the temperature range at which apatite does not decompose. By processing, apatite with controlled crystallinity, specific surface area, etc. can be obtained.

Examples of the above-mentioned phosphorus organic compounds used in the method of the present invention include (CH30)5P, CC2H50)3
P, [(CH3)2CHO)5F, (CH5(CH2)
so )3P, (C6Hs)3F, (C2H50)2
Examples include POH1(C15H5)5PO. Examples of the flammable organic solvent used include alcohols such as methanol, ethanol, and impropatol, and acetone. None of these are particularly limited, and as mentioned above, they form a solution with a uniform composition with one or two calcium salts selected from calcium nitrate, calcium chloride, and calcium bromide. Any combination of organic compounds or organic solvents for phosphorus to be obtained may be used. Calcium nitrate, calcium chloride, and calcium bromide usually contain water of crystallization, so even if a mixed solvent with water is not used, a small amount of water will be present in the system. The raw materials to be used may be selected depending on the desired calcium-phosphorus apatite. For example, when synthesizing hydroxyapatite, a calcium nitrate salt such as Ca(NO3)2.4H20 is used as the calcium salt. do it. In addition, when synthesizing chlorapatite, CaCl2・2H20, Ca(N05)2
・Combination use of 4H20 and CaCl2・2H2o, Ca(
By using NO3)2.4H20 and NH2Cl in combination, it is possible to obtain chlorapatite or a solid solution apatite of hydroxyagutite and chlorapatite. Similarly for brominated apatite, CaBr2 * 2H20
, Ca(NO3)2・4H20 and CaBr2・2H20
Bromine apatite or a solid solution apatite of bromine apatite and hydroxyapatite can be obtained by using a combination of Ca(NO3)2.4H20 and NH4Br, or the like.

The molar ratio Ca/'P of calcium to phosphorus in calcium-phosphorus apatite having a stoichiometric composition is 5/3, but in the actual reaction in the method of the present invention, the molar ratio Ca/'P of calcium to phosphorus in the raw material solution is 5/3. /1' is 1.25 to 1.7
Using solutions with compositions in the range 5.5, products with apatite as the main component are obtained in each case. Depending on the conditions, free generated CaO may remain, but depending on the application and
Depending on the purpose, the performance is sufficient to use it,
Naturally, such products are also included within the scope of the calcium-phosphorus apatite produced by the method of the present invention. Also, Ca/P is 1.25 or less or 1.75
The present inventors have demonstrated that even in the above cases, a product whose main component is apatite can be obtained by combining the raw materials.
It has been experimentally confirmed.

EXAMPLES Below, the present invention will be described in more detail and specifically with reference to Examples, but the present invention is not limited thereto.

Example 1 About 200 tons of Ca(NO5)2.4H2036,90t
(C2H50)5F in this solution.
15.58 f' was added and stirred to mix and dissolve, and ethanol was further added to prepare a uniform raw material solution with a total amount of 250. Next, this raw material solution was supplied at a rate of 10 -/min and compressed air at a rate of 10 t/min to the liquid supply side and the gas supply side of the two-fluid spray nozzle, and sprayed into the flame of the gas burner. The raw material solution, which had become fine droplets, was instantaneously heated by evaporation and combustion of the solvent in the flame, causing a thermal decomposition reaction. The temperature during the thermal decomposition reaction is 1050 to 1
The temperature was 105°C. The powder thus produced was collected using a cyclone method and observed under an electron microscope, and as a result, it was found to be a hollow spherical fine powder. Next, X of this generated powder
As a result of line diffraction analysis, the obtained powder contained both a crystalline phase and an amorphous phase of hydroxyapatite, and unreacted component CaO remained.

Example 2 The powder obtained by the method of Example 1 was heated for 5 minutes in an air atmosphere.
The temperature was raised at a rate of °C/min, heat treatment was performed at 1300 °C for 1 hour, and the mixture was cooled at a rate of 5 °C/min. The results of X-ray diffraction measurements of the product obtained by this heat treatment are shown in FIG. As is clear from FIG. 1, the product obtained in this example was hydroxyapatite (hexagonal crystal) with well-grown crystals, and no decomposition of hydroxyapatite was observed at high temperatures.

Example 3 CaCl2 2H2045,94f was dissolved in about 200-ethanol, and (C2H50)3F3 was added to this solution.
1.16 F was added and stirred to mix and dissolve, and ethanol was further added to prepare a uniform raw material solution with a total volume of 250 d. Next, this raw material solution was subjected to spray pyrolysis in the same manner as in Example 1. The results of X-ray diffraction measurements of this produced powder are shown in FIG. It is clear from Figure 2 that 5.
It was confirmed that this produced powder contained both a crystalline phase and an amorphous phase of chlorazotite.

Example 4 (a): The powder obtained by the method of Example 3 was heated at a rate of 5°C/min in an air atmosphere, maintained at a constant temperature for 1 hour, and heated at a rate of 5°C/min. In the heat treatment method of cooling at 400, 600, 800, and 1000° C., experiments were conducted at each temperature. As a result of measuring the X-ray diffraction of the product heat-treated at 400°C, it showed a diffraction pattern of chlorapatite similar to that shown in Figure 2, and the diffraction intensity was slightly thicker (and growth of crystallites was observed. 600
The results of X-ray diffraction measurements of the product heat-treated at .degree. X of the product heat-treated at 800°C
Figure 3 shows the measurement results of line diffraction. As a result of measuring X-ray diffraction of the product heat-treated at 1000° C., a diffraction pattern was obtained in which the diffraction peak due to calcium chloride phosphate decreased and diffraction lines due to the formation of chlorapatite were observed. Through this series of experiments, it was found that when a powder containing both chlorapatite and an amorphous phase (powder obtained by the method of Example 3) was heat-treated, chlorapatite remained as it was at 400°C, but It was confirmed that it changed to calcium chloride phosphate at temperatures above 100°C, and changed again to chlorapatite at temperatures higher than 100°C.

(b): Raise the temperature at a rate of 5°C/min in a powder air atmosphere obtained by the method of Example 3, hold at 1200°C for 1 hour, and cool at a rate of 5°C/min. did.

By this heat treatment, the obtained product was dissolved in nitric acid, and a clouding test using a silver nitrate solution was performed, and it was confirmed that silver chloride precipitated. The results of X-ray diffraction measurement of the above product are shown in FIG. As is clear from Fig. 4, this product is chlorapatite, and the main peak is the diffraction peak of (211)'' and 2 at the diffraction angle 2θ = 31.4°.
0・=32.3@to (112-) and (-sum, a), of・
(A recursive I-fold peak was measured.

Example 5 C&CNO5)2 ・4H2036,9Of about 180
- in ethanol, and in this solution (C2H50)5
Add P 15.58 f and stir to mix 1. Dissolved. Then, NH4Br 4.90? Add an aqueous solution of ammonium bromide prepared by dissolving it in 25 Tnt of water, mix well, and further mix with ethanol.
A uniform raw material solution having a total volume of 250 m was prepared. Then, this raw material solution was subjected to spray pyrolysis using the same method as in Example 1. The obtained powder was heat-treated under the same conditions as in Example 4. As a result of measuring the X-ray diffraction of the obtained product, it showed a hydroxyapatite type (hexagonal) diffraction pattern similar to that shown in FIG. 1, and the peak of freely generated CaO remained. Furthermore, when this product was dissolved in nitric acid and bromine was detected using a silver nitrate solution, silver bromide precipitated.
The presence of bromine was confirmed. Therefore, it can be seen that the product obtained in this example is a solid solution apatite of hydroxyapatite and bromine apatite.

Example 6 CaBr2.2H2036,87t was dissolved in about 180-ethanol, and (C2H50)5F15 was added to this solution.
．． 58 t was added, mixed and dissolved by stirring, and ethanol was further added to prepare a uniform raw material solution having a total amount of 250 t. Next, this raw material solution was subjected to spray pyrolysis in the same manner as in Example 1. The obtained powder was used in Example 4 (b
) The heat treatment was performed under the same conditions.

As a result of measuring X-ray diffraction of the obtained product, it showed the same diffraction pattern as in FIG. 4, and the presence of bromine was confirmed by the silver nitrate solution. Therefore, it can be seen that the above product is brominated apatite.

Examples 7-18 Ca(N05)2.4H20, CaCl2, CaCl2
・2H20, CaBr2・2H20, NHa"'1CC
HsO)sPs (C2H50)5F, ((CH3)2
CHO: 15F.

(CH3(CH2)30)5P, (C4)(so)5F
, (C6H5)51)Ol(C2H50)2POH, Mel/-#, ethanol, impropatol, acetone, H2O, etc., were used as raw material components and prepared according to the respective raw material blending ratios shown in Table 1, With respect to conditions other than those shown in Table 1, various calcium-phosphorus apatites were synthesized by carrying out a spray pyrolysis operation using the same material as in Example 1.

Note 1. Number r250J in the alcohol and acetone column
In each case, the total amount of the raw material solution is 250-
It means to dissolve alcohol or acetone.

Note 2. (H-B)AP is a solid solution apatite of hydroxyapatite and bromine apatite, (H-C)AP is a solid solution of hydroxyapatite and chlorapatite. Means molten apatite.

[Brief explanation of drawings]

Figure 1 shows the X of hydroxyapatite obtained in Example 2.
FIG. 2 is an X-ray diffraction diagram of chlorapatite obtained in Example 3. FIG. 3 is an X-ray diffraction diagram of calcium chloride phosphate obtained by heat treatment at 800°C in Example 4(a), and FIG. 4 is an X-ray diffraction diagram of chlorapatite obtained in Example 4(b). X
It is a line diffraction diagram. 1st / 3rd turn 1st 3rd turn

Claims (4)

[Claims] (1) One or two selected from calcium nitrate, calcium chloride, and calcium bromide for a water-compatible flammable organic solvent or a mixed solvent of a water-compatible flammable organic solvent and water. a calcium compound, an organic phosphorus compound soluble in the above solvent, and, if necessary, one selected from ammonium chloride and ammonium bromide.
A method for producing calcium-phosphorus apatite, which is characterized in that a raw material solution with a uniform composition is prepared by adding, mixing and dissolving seeds, and the raw material solution is sprayed into a flame or a heating zone to cause a thermal decomposition reaction. Production method. (2) One or two selected from calcium nitrate, calcium chloride, and calcium bromide for a water-compatible flammable organic solvent or a mixed solvent of a water-compatible flammable organic solvent and water. a calcium compound, an organic phosphorus compound soluble in the above solvent, and, if necessary, one selected from ammonium chloride and ammonium bromide.
Add seeds, mix and dissolve to prepare a raw material solution with a uniform composition, spray this raw material solution into a flame or heating zone to perform a thermal decomposition reaction, and heat treat the resulting powder. Characteristic method for producing calcium-phosphorus apatite. (3) The method according to each of claims 1 and 2, characterized in that a phosphorus alkoxide is used as the organic phosphorus compound. (4) The method according to each of claims 1 and 2, characterized in that triethyl phosphite is used as the organic compound of phosphorus.