JPH0218323A - Preparation of titanium dioxide from titanium alkoxide - Google Patents

Abstract

PURPOSE:To prepare titanium dioxide having reduced particle size and particle size distribution range and increased yield, and to enable recovery of by- produced alcohol with high purity by carrying out the hydrolysis of Ti alkoxide in two stages, synthesizing titanoxane in the first stage, and distilling off by- produced alcohol in the first and the second stage of the hydrolysis. CONSTITUTION:Water of 1.0-2.0 mole is added to 1 mole titanium alkoxide in form of an alcoholic soln. of water, and allowed to react with the titanium alkoxide, and by-produced alcohol is distilled off after heating and aging the reaction mixture. Thus, titanoxane contg. no monomer of the titanium alkoxide is synthesized. Then, an alcoholic soln. of water is added to the titanoxane and is allowed to react. In this second stage reaction, the amt. of the alcoholic soln. of water to be added is regulated to about 2-40 mole expressed in terms of sum of the water added in the first stage and that added in the second stage. By this method, by-produced alcohol having >=99.9% purity is recovered, and the capacity for production per one reaction vessel is increased. Moreover, the particle size of obtd. TiO2 is reduced to 0.3-1.0mu.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a new industrially advantageous manufacturing method for ceramic raw materials, pigments, cosmetic fine particle oxidation, and titanium.

[Prior Art and Problems to be Solved] The conventional method for producing titanium oxide from titanium alkoxide has the following advantages, and titanium oxide is obtained by hydrolyzing titanium alkoxide.

■Hydrolysis under mild conditions yields oxides.

■Less contamination with impurities. (High purity alkoxides are easily available).

■Particle size and shape can be changed by controlling hydrolysis.

However, titanium oxide obtained by hydrolysis of titanium alkoxide has a wide particle size distribution in -a, and the yield is generally low when obtaining a highly monodisperse product.

Furthermore, in either case, a large amount of solvent is required, and the current situation is that either the hydrous alcohol is recovered or a large amount of the solvent and by-product alcohol are discarded. Even if it is recovered and reused as hydrous alcohol, there will always be a surplus of by-product alcohol, and a process to recover pure alcohol will be necessary, but refining hydrous alcohol is by no means easy.

[Means to solve problems]

As a result of intensive research into industrially advantageous manufacturing methods, the present inventors found that titanium alkoxide has a
Preferably, 1.3 to 1.5 times the mole of water is reacted as an alcoholic solution of water, and after heating and aging, the by-product alcohol is distilled off, and the reaction solution is mixed with 1 mole of titanium alkoxide.
It was discovered that by-product alcohol with a purity of 99.9% or more could be recovered by adding and reacting an alcoholic solution of water so that the sum of the number of moles of water in the first stage was 2 to 40, and the present invention was completed. I let it happen.

That is, in the present invention, the hydrolysis of titanium alkoxide is divided into two stages, and titanoxane is synthesized in the first stage. In the reaction between titanium alkoxide and water, when the molar ratio is examined in detail, up to a reaction amount of water up to a molar ratio of 1.0 and preferably 1.3, titanoxane and titanium alkoxide monomer (hereinafter abbreviated as monomer) is used. ).

Therefore, if water exceeding this molar ratio is reacted at once, the particle size distribution will become wider. On the other hand, if the reaction is controlled at a low molar ratio, monodispersity will result, but unreacted monomers will remain and the yield will generally be low.

Next, alcohol is distilled off between the first and second stages.
If the molar ratio in the first stage is low, monomers will be entrained in the distilled alcohol. Conversely, if the molar ratio is high, the water content in the distilled alcohol will be high. Therefore, the molar ratio of the first stage is!
A suitable amount is 0 to 2.0, preferably 1.3 to 1.5 times the mole. The amount of alcohol to be distilled off may be determined by distilling off an appropriate amount based on material balance, etc.

This recovered alcohol can be widely used for other raw materials, etc., and its purity was confirmed to be 99.9% or higher through gas chromatography and moisture analysis.

Furthermore, in the second stage reaction, water or its alcohol solution was added dropwise so that the sum of the number of moles of water in the first stage reaction was 2 to 40 moles. After the second-stage hydrolysis is completed, a filtration operation is performed. For filtration, a general centrifuge, filter press, etc. can be used. The iIt liquid can be distilled and used in the first and second stage reactions with its azeotropic composition.

The obtained titanium oxide was heated to 100 to 14
Dry at 0°C for several hours to obtain a final product.

The titanium alkoxide used here is represented by the following formula -m, and titanium alkoxides of 02 to C4 are preferably used.

T i (OR) a (R is a primary, secondary, or tertiary hydrocarbon having 1 to 8 carbon atoms) In addition, the alcohol used corresponds to an alkoxy group in order to recover the by-product alcohol with high purity. It is preferable to use an alcohol ROH (R is the above-mentioned hydrocarbon).

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples.

Example 1 284.2 g of titanium tetraisopropoxide was placed in a reaction tank, and azeotropic isopropanol was added with water (containing 25.2 g of water, the amount of isopropanol was 1.4 times the molar amount at room temperature). (168.6g) was added and reacted. After aging at 80°C, it is concentrated at normal pressure to obtain recovered isopropanol and titanoxane with a purity of 99.9% or higher. After cooling, 35
g of water is hydrolyzed with an azeotropic composition of isopropanol.

Furthermore, 120 g of water is added to obtain a slurry of titanium oxide, which is filtered using a centrifuge and then dried at 110° C. to obtain a final product. The filtrate is distilled and azeotropic isopropanol is recovered and recycled to the first stage of the reaction and the second stage of the reaction.

The obtained titanium oxide was found to have a particle size of 0.3 to 0.7 μm and a specific surface area (BET method) using an electron microscope (SEM photo image, Figure 1).
was 250 m/g, and X-ray diffraction (Fig. 2) showed that the crystal form was amorphous.

Example 2 22.8 g of titanium tetraethoxide was placed in a reaction tank, and 63 g of azeotropic ethanol (containing 2.5 g of water) was added to react at room temperature so that the amount of water was 1.4 times the molar amount. 8
After aging at 0°C, it is concentrated at normal pressure to obtain recovered ethanol and titanoxane with a purity of 99.9% or higher. After cooling, 3.
5 g of water is hydrolyzed with azeotropic ethanol. Further, 12 g of water was added to obtain a slurry of titanium oxide, which was filtered with suction to obtain a slurry, and then dried at 110° C. to obtain a product. The i+ liquid is distilled and used as azeotropic ethanol in the first and second stages of the reaction. The obtained titanium oxide had a particle size of 0.4 to 0.8 μ-
1 specific surface area (BET method) was 210n(/g), and the crystal form was amorphous according to X-ray diffraction.

〔effect〕

According to the present invention, by-product alcohol that could not be effectively utilized in the past can be recovered with high purity, and the production amount per reaction tank can be increased.

The titanium oxide obtained by the present invention has a particle size of 0°3 to 1
．． Smaller than Oμ steel, specific surface area is 250~550r//
g (BET method), which is very large. Therefore, it is highly expected to be used in paints, raw materials for fine ceramics, catalysts, adsorbents, etc.

[Brief explanation of the drawing]

FIG. 1 is an electron micrograph showing the particle structure of titanium oxide obtained in Example 1. FIG. 2 is an X-ray diffraction chart of titanium oxide obtained in Example 1. FIG. 3 is an electron micrograph showing the particle structure of titanium oxide obtained in Example 2. Application Agent: Person (430) Nippon Soda Co., Ltd. (7125) Company: Yoshimi Figure 1 Figure 3 Figure 2 PS 5μm

Claims (3)

[Claims] (1) 1.0 times to 2.0 times more than titanium alkoxide
Add and react twice the mole of water as an alcohol solution of water,
A novel oxidation process characterized by heating and aging and distilling off a portion of the solvent and by-product alcohol to synthesize titanoxane that does not contain titanium alkoxide monomers, and then adding and reacting an alcoholic solution of water to this titanoxane. How titanium is manufactured. (2) The method according to claim 1, wherein the solvent used is combined with the alkoxide of titanium alkoxide, thereby making the recovery of the by-product alcohol effective. (3) Dividing the hydrolysis of titanium alkoxide into two stages,
Titanoxane was synthesized in the first stage, converted to titanium oxide in the second stage, and alcohol with a purity of 99.9% or more was recovered between the first and second stages, reducing the loss of by-product alcohol. A method according to claim 1 characterized by industrial advantages.