JP5531606B2 - Spherical crystalline titanium oxyoxalate powder and method for producing the same - Google Patents

Description

  The present invention relates to a spherical crystalline titanium oxyoxalate powder and a method for producing the same. The spherical crystalline titanium oxyoxalate powder of the present invention is a spherical powder having a stable particle size, so that it has excellent dispersibility, is excellent as a catalyst used in a dispersion system, and has a particle size by using this product as an intermediate raw material. It is possible to obtain various titanium compounds which are stable spherical powders, and these titanium compounds can also be suitably used for various applications as having excellent dispersibility.

  The use of titanium oxyoxalate as a polycondensation catalyst for producing polyester is described in Patent Document 1, but there is no description about the production method of titanium oxyoxalate, and there is no description about particle size or shape. It was.

  Patent Document 2 describes the use as a precursor of titanium dioxide, but there is no description of a production method of titanium oxyoxalate itself, and there is no description of particle size and shape.

  As a method for synthesizing titanium oxyoxalate, Non-Patent Document 1 discloses that titanium hydroxide is dissolved in hydrochloric acid and oxalic acid is added thereto. In Non-Patent Document 2, crystalline titanium oxyoxalate can be obtained by adding a titanium oxynitrate aqueous solution prepared from titanium tetrachloride and nitric acid to an ethanol solution of oxalic acid and stirring at 60 ° C. for 12 hours. It is shown. However, crystalline titanium oxyoxalate powder having a spherical shape has not been known.

  That is, spherical crystalline titanium oxyoxalate is an unknown problem, and a production method capable of obtaining spherical crystalline titanium oxyoxalate has not been known. However, taking into account that various titanium compounds such as titanium oxyoxalate as a catalyst and titanium oxide obtained from titanium oxyoxalate as an intermediate are used in many dispersions, the particle size is controlled in a spherical shape. Since it is clear that it is excellent in dispersibility, filling properties, etc., the spherical crystalline titanium oxyoxalate is desirable itself and as an intermediate of the titanium compound. .

JP-A-2001-190963 JP 2003-252626 A

Kyoritsu Shuppan 1960, chemistry dictionary 2, page 62 Choi, H .; -L. , Powder Diffraction, Vol. 9, pp. 187-188 (1994)

  An object of the present invention is to provide a spherical crystalline titanium oxyoxalate powder.

As a result of intensive studies to solve the above problems, the present inventors have reacted titanyl oxysulfate and oxalic acid under specific conditions, and wet ripened to form a spherical crystalline oxy represented by the following formula [1]. The inventors have found that titanium oxalate powder can be obtained, and found that the particle size of the spherical crystalline titanium oxyoxalate powder can be controlled by limiting the reaction and aging conditions, thereby completing the present invention. That is, the present invention is a spherical crystalline titanium oxyoxalate powder and a production method thereof, and a production method capable of controlling the particle size.

(TiO) ₂ OC ₂ O ₄ .nH ₂ O [1]

(In the formula [1], n is an integer of 1 to 12, and different n may be included.)

  According to the spherical crystalline titanium oxyoxalate powder and the method for producing the same of the present invention, spherical crystalline titanium oxyoxalate can be obtained, which can be controlled in particle size. In addition, since the spherical crystalline titanium oxyoxalate powder of the present invention is an intermediate raw material for various titanium compounds, it can also be a raw material capable of providing a spherical titanium compound having a controlled particle size, particularly a spherical titanium oxide.

SEM photograph of titanium oxyoxalate powder obtained in Example 4 The X-ray-diffraction figure which measured the titanium oxyoxalate powder obtained in Example 4 with the powder X-ray-diffraction apparatus. The X-ray-diffraction figure which measured the powder obtained by the comparative example 2 with the powder X-ray-diffraction apparatus. Particle size distribution chart of laser diffraction particle size distribution meter of titanium oxyoxalate powder obtained in Example 4

The present invention will be described below. Unless otherwise specified,% is% by mass.
The spherical crystalline titanium oxyoxalate powder of the present invention is a spherical compound crystal represented by the following formula [1].

(TiO) ₂ OC ₂ O ₄ .nH ₂ O [1]

(In the formula [1], n is an integer of 1 to 12, and different n may be included.)

  The crystalline titanium oxyoxalate of the present invention can be confirmed by a powder X-ray diffraction pattern. The diffraction pattern is described in ASTM File No. 48-1164 and Non-Patent Document 2, and the d value is 3.352 (100), 4.621 (90), 3.221 (78), 6.475. (65), 4.236 (62), 2.844 (45), 1.885 (44), 2.595 (36), 4.189 (26), 7.763 (24). The numbers in parentheses are numbers indicating the X-ray diffraction intensity at each d value as relative intensity when the x-ray diffraction intensity at d = 3.352 is (100). The d value is a physical numerical value indicating the crystal plane interval in angstrom units, but unit angstroms are conventionally omitted.

  In the powder X-ray diffraction pattern, it is described in Patent Document 2 that titanium oxide exhibits a characteristic diffraction peak at d value = 3.464, but in the present invention, a characteristic diffraction peak of a titanium oxyoxalate crystal is described. X-ray diffraction intensity of d value = 3.352 (corresponding to diffraction angle 2θ = 26.57 ° when measured with CuKα ray) is d value = 3.464 indicating titanium oxide (measured with CuKα ray) In this case, the diffraction intensity is preferably 1,000 times or more, more preferably 3,000 times or more of the diffraction intensity at a diffraction angle 2θ = 25.72 °. When expressed by the absolute value of the X-ray diffraction intensity cps when measured using CuKα rays at 40 kv / 150 mA, which is a common-sense measurement condition, 3000 cps or more is preferable at a diffraction angle 2θ = 26.57 °, more preferably Is preferably 4000 cps or more, and at the same time, the X-ray intensity of 2θ = 25.72 ° indicated by titanium oxide is preferably 100 cps or less.

  If the X-ray diffraction intensity at 2θ = 26.57 ° is less than 3000 cps under these measurement conditions, the crystallinity may be low, or the purity may be lowered by mixing with other products. Preferably, it is 3000 cps or more because it is a single crystal having stable physical properties. In addition, when titanium oxide is mixed, not only the ratio of the titanium oxyoxalate crystal is reduced, but also the chemical reactivity of the titanium oxyoxalate crystal is lowered. Therefore, the diffraction angle 2θ = 25.72 indicating titanium oxide. The X-ray intensity at ° is preferably 100 cps or less.

  The crystalline titanium oxyoxalate powder of the present invention is spherical. It is difficult to control a sphere to be a perfect sphere. In SEM observation, the sphere includes those that are somewhat flat or have a “substantially spherical” shape with some surface irregularities. Other than the production method of the present invention, it is difficult to obtain a spherical shape, and the shape becomes an ellipsoidal to cylindrical shape, an annular shape, a crushed shape, an indefinite shape, or the like. The distinction of these shapes is obvious at a glance when observed with a scanning electron microscope (SEM), but the definition of sphere in the present invention is that it looks circular from any direction, and any point on the surface of the particle. The length of a line from a to a different point b is x, the line connecting points a to b where x is the maximum value is the particle long axis, and points a to b where x is the minimum value In the particle group, particles having a ratio of the length of the particle minor axis to the particle major axis in the range of 0.5 to 1 account for 60% or more of all particles. Occupy. An ellipsoid is defined when the ratio of the minor particle axis to the major particle axis is 0.5 or less, and a cylindrical shape is defined when the end surface of the major particle axis has a planar area of 3 area% or more and 97% or less of the surface area.

  The particle size gives slightly different values depending on the measurement principle, but the particle size and particle size values in the present invention are based on a general laser diffraction particle size distribution meter, and the median diameter calculated on a volume basis is used. Can be defined as the particle size representative of the powder. According to the production method of the present invention, spherical crystalline titanium oxyoxalate powder having a median diameter of 0.05 to 30 μm can be obtained. The preferred particle size is 0.1 to 20 μm, more preferably 0.3 to 15 μm, and it is easy to obtain a particle having a uniform particle size and good shape stability.

The particle size of the spherical crystalline titanium oxyoxalate powder of the present invention can be controlled by the synthesis conditions. For example, the size of the median diameter and the state of the particle size distribution can be changed depending on the stirring force, the heating rate, the aging temperature, etc. Can do. Even if the median size is the same, the particle size distribution is too wide and there are many coarse particles and fine particles. In the present invention, it is preferable that the particle size distribution width is narrow, and the particle size distribution defined by the formula [2] is preferable. The σ value is preferably 1 or more and 3.5 or less.

σ = (D ₁ / D ₂ ) ^0.5 [2]

(D ₁ is the particle diameter when the accumulation is 84% on the volume basis, and D ₂ is the particle diameter when the accumulation is 16% on the volume basis.)

More preferably, the σ value is 1 or more and 2.5 or less, and more preferably 1 or more and 2 or less. Since the spherical crystalline titanium oxyoxalate powder of the present invention has a uniform chemical component, the true density is constant, and the volume-based and mass-based particle size distributions have the same value.

  Crystal water contained in the spherical crystalline titanium oxyoxalate powder of the present invention is 1 to 12 for n in the formula [1], and a 12-hydrate salt is usually formed in an aqueous solution. In general drying conditions, those having n of about 2 to 5 are easily obtained.

  Although there is no limitation on the production method of the spherical crystalline titanium oxyoxalate powder in the present invention, it can be obtained by a production method in which an aqueous titanium solution is mixed with an aqueous oxalic acid solution at a specific mixing ratio and then aged under specific conditions. This is a preferred production method.

In the titanium aqueous solution, titanyl oxysulfate is used by dissolving in water. The concentration of the titanyl oxysulfate aqueous solution depends on the water temperature, but it can be 0.1 to 5 mol / L (liter), and is preferably 1 to 5 mol / L, more preferably 2 to 5 in consideration of productivity. 4 mol / L. The other raw material, oxalic acid, can be used either anhydrous or dihydrate. The concentration of the oxalic acid aqueous solution may also be in the concentration range of 0.1 to 5 mol / L, preferably 0.5 to 2 mol / L, depending on the water temperature. The mixing ratio (molar ratio) of oxalic acid when titanyl oxysulfate is 1 can be 0.4 to 0.65, preferably 0.42 to 0.6, and 0.45 to 0.55. More preferred.

  There is no limitation on the mixing order of oxalic acid and titanyl sulfate, and titanyl sulfate may be added dropwise to oxalic acid, or oxalic acid may be added dropwise to titanyl sulfate, or may be added dropwise at the same time. The dropping time and dropping temperature are not limited, but the dropping time is preferably within 1 minute to 10 hours, and more preferably between 5 minutes and 1 hour. The dropping temperature is preferably 100 ° C. or lower, more preferably 1 ° C. or higher and 80 ° C. or lower, more preferably 10 ° C. or higher and 50 ° C. or lower.

  After completion of the dropping of the raw material, crystallization of titanium oxyoxalate proceeds by heating and aging in the solution, and powder is deposited. A preferable aging temperature is 50 ° C to 100 ° C. Crystallinity cannot be obtained at 50 ° C. or less, or a long time is required until it is obtained, and if it exceeds a high temperature, particularly 100 ° C., water is boiled at atmospheric pressure, so a pressure reactor is necessary and economical. Therefore, it is more preferably 60 ° C to 80 ° C. When the aging temperature is 60 ° C. to 80 ° C., titanium oxyoxalate powder can be obtained in several hours to tens of hours. Moreover, finer titanium oxyoxalate powder is obtained as the temperature is lower. The obtained titanium oxyoxalate suspension can be washed with deionized water by a method such as repeating a ceramic filter or washing filtration. Washing with water until the electric conductivity of the filtrate is 500 μS (Siemens) or less is preferable because impurities are sufficiently removed.

  Since the spherical crystalline titanium oxyoxalate powder of the present invention has a spherical shape with a controlled particle size, the titanium compound synthesized using this as a raw material is likely to be spherical or uniform and spherical. Titanium oxide can be easily obtained. According to the synthesis conditions of the target titanium compound, the spherical titanium oxyoxalate of the present invention can be provided in the form of an aqueous dispersion, a wet powder, a dry powder or the like. Further, for example, in the case of synthesis of titanium oxide, the spherical titanium oxyoxalate of the present invention can be heat-treated at a high temperature to obtain titanium oxide while maintaining the spherical form and particle size.

EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to this.
The XRD diffraction intensity is a specific reflection angle (2θ = 26.57 ° which is a typical peak showing a crystalline titanium oxyoxalate compound) when measured by CuKα ray under a measurement condition of 40 kv / 150 mA with a powder X-ray diffractometer. This is a measured value of the X-ray diffraction intensity. In order to confirm the spherical shape, it was observed with a scanning electron microscope (SEM) at a magnification of several thousand to 10,000 times. The median diameter and the maximum particle diameter are values measured using a laser diffraction particle size distribution analyzer and analyzed on a volume basis.

<Example 1>
200 mL of deionized water and 0.5 mol of titanyl oxysulfate were added to a 1 liter glass flask, heated and dissolved at 40 ° C. A 50 ° C. aqueous solution prepared by adding 0.25 mol of oxalic acid dihydrate to 250 mL of deionized water was added dropwise over 20 minutes. After completion of dropping, the mixture was stirred at 1500 rpm and 60 ° C. for 8 hours. Thereafter, the resulting precipitate was thoroughly washed with deionized water, dried at 120 ° C. for 4 hours, and then lightly crushed in a mortar to synthesize titanium oxyoxalate powder.
The obtained titanium oxyoxalate was examined by XRD diffraction measurement to determine the presence or absence of crystalline impurities and the X-ray intensity at 2θ = 26.57 ° indicating the titanium oxyoxalate compound. The shape and the like were confirmed by SEM observation, and the results of measuring the particle size and median diameter with a laser diffraction particle size distribution analyzer are shown in Table 1. A diffraction peak at 2θ = 25.72 ° indicating titanium oxide was not observed.

<Example 2>
200 mL of deionized water and 0.45 mol of titanyl oxysulfate were added to a 1 liter glass flask and dissolved at 30 ° C. An aqueous solution at 30 ° C. in which 0.25 mol of oxalic acid dihydrate was added and dissolved in 250 mL of deionized water was added dropwise over 20 minutes. After completion of dropping, the mixture was stirred at 1000 rpm and 80 ° C. for 6 hours. Thereafter, the obtained precipitate was thoroughly washed with deionized water, dried at 120 ° C. for 4 hours, and then crushed to synthesize titanium oxyoxalate.
The obtained titanium oxyoxalate was examined by XRD diffraction measurement to determine the presence or absence of crystalline impurities and the X-ray intensity at 2θ = 26.57 ° indicating the titanium oxyoxalate compound. The shape and the like were confirmed by SEM observation, and the results of measuring the particle size and median diameter with a laser diffraction particle size distribution analyzer are shown in Table 1. A diffraction peak at 2θ = 25.72 ° indicating titanium oxide was not observed.

<Example 3>
To a glass flask having a capacity of 1 liter, 250 mL of deionized water and 0.25 mol of oxalic acid dihydrate were added and dissolved at 30 ° C. An aqueous solution at 30 ° C. in which 0.5 mol of titanyl oxysulfate was dissolved in 250 mL of deionized water was added dropwise over 20 minutes. After completion of dropping, the mixture was stirred at 1000 rpm and 95 ° C. for 6 hours. Thereafter, the obtained precipitate was washed well, dried at 120 ° C. for 4 hours, and then crushed to synthesize titanium oxyoxalate.
The obtained titanium oxyoxalate was subjected to XRD diffraction measurement to examine the presence or absence of crystalline impurities and the X-ray intensity at 2θ = 26.57 ° indicating the titanium oxyoxalate compound. The shape and the like were confirmed by SEM observation, and the results of measuring the particle size and median diameter with a laser diffraction particle size distribution analyzer are shown in Table 1. A diffraction peak at 2θ = 25.72 ° indicating titanium oxide was not observed.

<Example 4>
0.45 mol of titanyl oxysulfate was added to 200 mL of deionized water and dissolved at 20 ° C. An aqueous solution at 30 ° C. in which 0.25 mol of oxalic acid dihydrate was added and dissolved in 250 mL of deionized water was added dropwise over 20 minutes. After completion of dropping, the mixture was stirred at 2000 rpm and 80 ° C. for 6 hours. Thereafter, the obtained precipitate was thoroughly washed, dried at 120 ° C. for 4 hours, and then crushed to synthesize titanium oxyoxalate.
The obtained titanium oxyoxalate was examined by XRD diffraction measurement to determine the presence or absence of crystalline impurities and the X-ray intensity at 2θ = 26.57 ° indicating the titanium oxyoxalate compound. The shape and the like were confirmed by SEM observation, and the results of measuring the particle size and median diameter with a laser diffraction particle size distribution analyzer are shown in Table 1. A diffraction peak at 2θ = 25.72 ° indicating titanium oxide was not observed.

  The particle size distribution diagram of the spherical crystalline titanium oxyoxalate obtained in Example 4 is shown in FIG. 4. The particle size that is 16% in total on the volume basis is 2.8 μm, and the particle size that is 84% in total is 6. Since it was 1 μm, the σ value was calculated to be 1.5. The σ values were similarly calculated for other examples and are shown in Table 1.

<Example 5>
0.5 mol of titanyl oxysulfate was added to 200 mL of deionized water and dissolved at 20 ° C. To 250 mL of deionized water, 0.25 mol of oxalic acid dihydrate was added and dissolved at 40 ° C. An aqueous solution of titanyl oxysulfate and an aqueous oxalic acid solution were simultaneously added dropwise to 300 mL of deionized water in 30 minutes. After completion of dropping, the mixture was stirred at 2000 rpm and 60 ° C. for 6 hours. Thereafter, the obtained precipitate was thoroughly washed, dried at 120 ° C. for 4 hours, and then crushed to synthesize titanium oxyoxalate.
The obtained titanium oxyoxalate was examined by XRD diffraction measurement to determine the presence or absence of crystalline impurities and the X-ray intensity at 2θ = 26.57 ° indicating the titanium oxyoxalate compound. The shape and the like were confirmed by SEM observation, and the results of measuring the particle size and median diameter with a laser diffraction particle size distribution analyzer are shown in Table 1. A diffraction peak at 2θ = 25.72 ° indicating titanium oxide was not observed.

<Example 6>
0.5 mol of titanyl oxysulfate was added to 200 mL of deionized water and dissolved at 20 ° C. An aqueous solution at 20 ° C., in which 0.25 mol of oxalic acid dihydrate was added and dissolved in 350 mL of deionized water, was added dropwise over 120 minutes. 4 hours after the completion of dropping, the temperature was raised to 60 ° C. over 2 hours, and the mixture was further stirred for 12 hours at 2000 rpm. Thereafter, the obtained precipitate was washed well, dried at 120 ° C. for 4 hours, and then crushed to synthesize titanium oxyoxalate.
The obtained titanium oxyoxalate was examined by XRD diffraction measurement to determine the presence or absence of crystalline impurities and the X-ray intensity at 2θ = 26.57 ° indicating the titanium oxyoxalate compound. The shape and the like were confirmed by SEM observation, and the results of measuring the particle size and median diameter with a laser diffraction particle size distribution analyzer are shown in Table 1. A diffraction peak at 2θ = 25.72 ° indicating titanium oxide was not observed.

<Example 7>
50 L of titanyl oxysulfate was added to 20 L of deionized water and dissolved at 50 ° C. An aqueous solution at 50 ° C. in which 25 mol of oxalic acid dihydrate was dissolved in 25 L of deionized water was added dropwise over 10 minutes. After completion of dropping, the temperature was raised to 95 ° C. over 30 minutes, and the mixture was further stirred at 500 rpm for 8 hours. Thereafter, the obtained precipitate was washed well, dried at 120 ° C. for 4 hours, and then crushed to synthesize titanium oxyoxalate.
The obtained titanium oxyoxalate was examined by XRD diffraction measurement to determine the presence or absence of crystalline impurities and the X-ray intensity at 2θ = 26.57 ° indicating the titanium oxyoxalate compound. The shape and the like were confirmed by SEM observation, and the results of measuring the particle size and median diameter with a laser diffraction particle size distribution analyzer are shown in Table 1. A diffraction peak at 2θ = 25.72 ° indicating titanium oxide was not observed.

<Comparative Example 1>
0.5 mol of titanyl oxysulfate was added to 200 mL of deionized water and dissolved at 40 ° C. An aqueous solution at 40 ° C., in which 0.25 mol of oxalic acid dihydrate was added to 250 mL of deionized water and dissolved, was added dropwise over 20 minutes. After completion of dropping, the mixture was stirred at 1500 rpm and 40 ° C. for 24 hours. Thereafter, the obtained precipitate was washed well, dried at 120 ° C. for 4 hours, and then crushed.
The obtained titanium oxyoxalate was examined by XRD diffraction measurement to determine the presence or absence of crystalline impurities and the X-ray intensity at 2θ = 26.57 ° indicating the titanium oxyoxalate compound. The shape and the like were confirmed by SEM observation, and the results of measuring the particle size and median diameter with a laser diffraction particle size distribution analyzer are shown in Table 1. The obtained compound was amorphous with low crystallinity and almost no diffraction peak appeared in X-ray diffraction.

<Comparative example 2>
0.5 mol of titanyl oxysulfate was added to 200 mL of deionized water and dissolved at 40 ° C. An aqueous solution at 50 ° C. in which 0.19 mol of oxalic acid dihydrate was added and dissolved in 250 mL of deionized water was added dropwise over 20 minutes. After completion of dropping, the mixture was stirred at 1500 rpm and 80 ° C. for 8 hours. Thereafter, the obtained precipitate was washed well, dried at 120 ° C. for 4 hours, and then crushed.
The obtained titanium oxyoxalate was examined by XRD diffraction measurement to determine the presence or absence of crystalline impurities and the X-ray intensity at 2θ = 26.57 ° indicating the titanium oxyoxalate compound. The shape and the like were confirmed by SEM observation, and the results of measuring the particle size and median diameter with a laser diffraction particle size distribution analyzer are shown in Table 1. The obtained compound was not spherical in shape, but was agglomerated with irregularities such as small particle aggregates. Further, as shown in FIG. 3, the powder X-ray diffraction pattern has a small diffraction peak of 2θ = 26.57 °. However, the X-ray diffraction pattern of the titanium oxyoxalate of the present invention shown in FIG. Since the patterns were completely different, it was determined that the titanium oxyoxalate of the present invention was a compound having a different crystal system. The diffraction peak intensity at 2θ = 25.72 ° indicating titanium oxide was 210 cps, and the diffraction intensity ratio with the peak at 2θ = 26.57 ° was about 13.

<Comparative Example 3>
To 200 mL of an aqueous nitric acid solution, 0.2 mol of titanium tetrachloride was added and stirred at 40 ° C. An aqueous solution at 50 ° C., in which 0.1 mol of oxalic acid dihydrate was added to 250 mL of ethanol and dissolved, was added dropwise over 20 minutes. After completion of dropping, the mixture was stirred at 1500 rpm and 60 ° C. for 8 hours. Thereafter, the obtained precipitate was washed well, dried at 120 ° C. for 4 hours, and then crushed.
The obtained titanium oxyoxalate was examined by XRD diffraction measurement to determine the presence or absence of crystalline impurities and the X-ray intensity at 2θ = 26.57 ° indicating the titanium oxyoxalate compound. The shape and the like were confirmed by SEM observation, and the results of measuring the particle size and median diameter with a laser diffraction particle size distribution analyzer are shown in Table 1. The obtained compound had a powder X-ray analysis pattern of titanium oxyoxalate, but had a cylindrical shape. A diffraction peak at 2θ = 25.72 ° indicating titanium oxide was not observed.

In Examples 1 to 7, it was confirmed from the results in Table 1 that spherical crystalline titanium oxyoxalate was obtained. On the other hand, the product of Comparative Example 1 having a low ripening temperature has a low crystallinity and is not spherical in shape, and the product of Comparative Example 2 has a oxalic acid blending ratio of 0.38 when titanyl oxysulfate is 1. Was not spherical in shape and was different in crystal system from the crystalline titanium oxyoxalate of the present application. Moreover, although the product of the comparative example 3 synthesize | combined with the existing manufacturing method using the titanium tetrachloride as a raw material was crystalline titanium oxyoxalate, the shape was not spherical but cylindrical.

  Since the spherical crystalline titanium oxyoxalate of the present invention has a spherical shape with a controlled particle size, the titanium compound synthesized using this as a raw material is easy to obtain a spherical or uniform and spherical product, and particularly a spherical titanium compound. Is obtained.

2 and 3 represents the X-ray intensity (unit: cps) in the powder X-ray diffraction measurement.
2 and 3 represents the X-ray diffraction angle 2θ (unit: °).
The vertical axis in FIG. 4 represents the volume fraction (unit%) of particles having the particle diameter when the whole is taken as 100%.
The horizontal axis in FIG. 4 represents the particle size (unit: micrometers).

Claims (5)

A crystalline titanium oxyoxalate powder represented by the following formula [1] having a spherical shape.
(TiO) ₂ OC ₂ O ₄ .nH ₂ O [1]
(In Formula [1], n is 1-12.) In the powder X-ray diffraction pattern, the X-ray diffraction intensity of d value 3.352, which is a characteristic diffraction peak of titanium oxyoxalate crystal, is d value = 3.464, which is a characteristic diffraction peak of titanium oxide crystal. The spherical crystalline titanium oxyoxalate powder according to claim 1, which has a diffraction intensity of 1,000 times or more with respect to the diffraction intensity. The spherical crystalline titanium oxyoxalate powder according to claim 1 or 2, wherein a volume-based median diameter measured by a laser diffraction particle size distribution meter is in a range of 0.05 to 30 µm. The spherical crystalline titanium oxyoxalate powder according to claim 1, wherein the σ value of the particle size distribution defined by the formula [2] is 1 or more and 3.5 or less.
σ = (D ₁ / D ₂ ) ^0.5 [2]
(D ₁ is the particle diameter when the accumulation is 84% on the volume basis, and D ₂ is the particle diameter when the accumulation is 16% on the volume basis.) A method for producing crystalline titanium oxyoxalate powder using titanyl oxysulfate and oxalic acid, wherein the mixing ratio (molar ratio) of oxalic acid when the titanyl oxysulfate is 1 is 0.4 to 0.65. The method for producing crystalline titanium oxyoxalate powder according to claim 1 , wherein the aqueous solution containing titanyl oxysulfate and the aqueous solution containing oxalic acid are mixed and then heated to 50 ° C. or higher.