Preparation method of rutile phase nano-titanium dioxide with controllable particle size

Abstract

The application discloses a preparation method of rutile phase nano titanium dioxide with controllable particle size, which comprises the following steps: constructing a water bath reaction environment by using a mixed solution of anhydrous ethanol and super-dry acetonitrile, adding benzoic acid, making the benzoic acid react with tetrabutyl titanate in the reaction environment and controlling the hydrolysis process of the tetrabutyl titanate, adding a mixed solution containing deionized water into the reaction to add appropriate hydrolysis sites into the formed tetrabutyl titanate-benzoic acid complex, then treating the precipitate and grinding the precipitate into a semi-finished powder, and finally carrying out microwave hydrothermal reaction on the semi-finished powder and anhydrous oxalic acid to obtain the rutile phase nano titanium dioxide with controllable particle size. The preparation method of the rutile phase nano titanium dioxide with controllable particle size effectively avoids high temperature and long time reaction required by traditional high-temperature calcination, is simple in overall scheme steps, convenient to operate, relatively low in material cost, safe and controllable in process, and clean and environmentally-friendly.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of nanometer material preparation, and particularly relates to a preparation method of rutile phase nanometer titanium dioxide with controllable particle size. BACKGROUND

[0002] Multilayer ceramic capacitor (MLCC) is one of the largest and fastest growing chip components in the world, which has the characteristics of wide capacity range, good frequency characteristics, small loss, wide working voltage and temperature range, and ultra-small volume. With the development of computer, network equipment, 5G mobile phone, new energy automobile and other electronic industries and the miniaturization trend of equipment, MLCC has become the preferred capacitor type in the electronic industry, and the market demand is increasing, therefore, MLCC is also known as the "pillar of electronic ceramic industry". With the development of new electronic components towards chip, miniaturization, high frequency, wide frequency, high precision, integration and green environmental protection, MLCC technology also continues to develop rapidly, and high-end MLCC with high capacity, ultra-small volume, high frequency and high temperature, high voltage resistance and higher reliability has always been the pursuit of the electronic industry. In order to achieve these performance requirements, one of the key points of research is titanium dioxide (TiO2) material.

[0003] TiO2 is an important raw material for synthesizing barium titanate powder by solid phase method or hydrothermal method, and the particle size of barium titanate powder is proportional to the particle size of titanium dioxide and inversely proportional to its specific surface area, so how to control the synthesis of TiO2 becomes the key problem to solve the uniformity and dispersibility of BaTiO3 powder. BaTiO3 is an inorganic strong dielectric material with high dielectric properties, low dielectric loss, good dielectric adjustability and moderate breakdown field strength (BDS). Studies have shown that the grain size of BaTiO3 seriously affects the dielectric constant, dielectric loss and BDS of ceramics and thin films. The capacitance of barium titanate increases with the increase of the relative dielectric constant of the dielectric layer and the number of dielectric layers, and decreases with the decrease of the thickness of the dielectric layer, and the increase of the number of dielectric layers and the decrease of the thickness of the dielectric layer both depend on the small particle size of BaTiO3 powder. Therefore, the particle size of TiO2 powder has a decisive influence on the performance of MLCC products.

[0004] Rutile titanium dioxide has excellent heat resistance, thermal stability, chemical stability and can be widely used in paint, cosmetics and ceramics and other fields. Its preparation method mainly includes liquid phase method, solid phase method and gas phase method. Among them, solid phase method and gas phase method consume large energy, the purity of the product is low, the morphology and size of the product cannot be accurately controlled and it is difficult to industrialize production; liquid phase method includes sol-gel method, hydrothermal method, liquid phase precipitation method and microemulsion method, however, when the liquid phase method is used for preparation, due to the too fast hydrolysis rate of titanium precursor, it is difficult to prepare rutile titanium dioxide powder with high yield, high uniformity and high sphericity, and in the traditional preparation scheme, high temperature calcination needs to be experienced, and the energy consumption is too large. Therefore, it is urgent to develop a suitable method to prepare rutile titanium dioxide powder with high uniformity and high dispersion. SUMMARY

[0005] The technical problem to be solved by the present application is to provide a preparation method of rutile phase nano titanium dioxide with controllable particle size, which solves the problems of non-uniform particle size, difficult particle size control and easy agglomeration of nano rutile titanium dioxide powder.

[0006] The technical solution of the present application to solve the above technical problem is:

[0007] A preparation method of rutile phase nano titanium dioxide with controllable particle size, comprising the following steps:

[0008] S1, anhydrous ethanol and super dry acetonitrile are put into a reaction vessel for mixing, after complete mixing, benzoic acid is slowly dropped into the mixed solution for water bath reaction in a stirring environment of 500 r / min, until the benzoic acid is completely dispersed in the mixed solution, to obtain system A;

[0009] S2, continue to stir at 500 r / min, slowly drop tetrabutyl titanate into system A for water bath reaction, until the mixed solution is light yellow, to obtain system B;

[0010] S3, first, anhydrous ethanol and super dry acetonitrile are put into a reaction vessel for mixing, after complete mixing, deionized water is dropped into the mixed solution for water bath reaction in a stirring environment of 500 r / min, to obtain system C;

[0011] S4, continue to stir at 500 r / min, quickly pour system C into system B for water bath reaction, to obtain system D;

[0012] S5, after washing, precipitation and drying of system D, the dried product is ground to have a delicate feeling, to obtain a semi-finished powder;

[0013] S6, the semi-finished powder is poured into deionized water for stirring, until the semi-finished powder is completely dispersed in the water, then anhydrous oxalic acid is added for microwave hydrothermal reaction, and the reaction is completed to obtain a reaction solution;

[0014] S7, the reaction liquid is sequentially subjected to ultrasonic, washing, centrifugation and drying treatment to obtain uniform rutile phase nano titanium dioxide;

[0015] The volume ratio of the anhydrous ethanol to the ultradry acetonitrile solution in the step S1 and the volume ratio of the anhydrous ethanol to the ultradry acetonitrile solution in the step S3 are 1:4, and the addition ratio of the anhydrous ethanol to the ultradry acetonitrile is 1:1.

[0016] The molar ratio of the addition amount of the benzoic acid to the addition amount of the tetrabutyl titanate is 0.05-0.5:1.

[0017] Preferably, the molar ratio of the addition amount of the benzoic acid to the addition amount of the tetrabutyl titanate is 0.15-0.4:1.

[0018] Specifically, the volume ratio of the addition amount of the tetrabutyl titanate to the total addition amount of the anhydrous ethanol and the ultradry acetonitrile is 1:50.

[0019] Preferably, in the step S1, the stirring time is at least 30 min, and the reaction temperature of the water bath reaction is 25-35℃.

[0020] Preferably, in the step S2, the stirring time is at least 1 h, and the reaction temperature of the water bath reaction is 25-35℃.

[0021] Specifically, in the step S3, the volume ratio of the addition amount of the water to the addition amount of the anhydrous ethanol and the ultradry acetonitrile is 1-20:200; the stirring time is at least 30 min, and the water bath temperature is 25-35℃.

[0022] Preferably, in the step S4, the stirring time is at least 2 h, and the reaction temperature of the water bath reaction is 25-35℃.

[0023] Specifically, in the step S6, the mass ratio of the addition amount of the semi-finished product powder to the addition amount of the anhydrous oxalic acid is 5-15:1-3; the volume of the deionized water is 25-50 mL; the reaction time of the microwave hydrothermal reaction is 20 min, and the reaction temperature is 160-220℃.

[0024] Preferably, in the step S5, the washing includes deionized water washing and anhydrous ethanol washing, wherein the deionized water washing is once, and the anhydrous ethanol washing is twice; the drying is performed by using a vacuum drying box, the drying temperature is 60℃, and the drying time is 8 hours.

[0025] The present application has the following beneficial effects: acetonitrile is used to ensure a reliable reaction environment for the dispersion of titanium dioxide, benzoic acid is used to realize the formation of amorphous titanium dioxide and the size control of titanium dioxide in a very short induction time, and finally, the microwave hydrothermal method is used to solidify titanium dioxide to form stable and uniform rutile phase nanometer titanium dioxide, thereby effectively avoiding the high temperature and long reaction time required by traditional high-temperature calcination, the overall scheme is simple and easy to operate, the cost of the materials used is relatively low, the process is safe and controllable, and clean and environmentally friendly. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 It is an electron microscope picture of the semi-finished powder (left) and the final product (right) in Example 1 of the present application.

[0027] Figure 2 It is an XRD diffraction spectrum of the semi-finished powder (a) and the final product (b) in Example 1 of the present application.

[0028] Figure 3 It is an electron microscope picture of the semi-finished powder (left) and the final product (right) in Example 2 of the present application.

[0029] Figure 4 It is an electron microscope picture of the final product of Comparative Example 1 of the present application.

[0030] Figure 5 It is an electron microscope picture of the final product of Comparative Example 2 of the present application. DETAILED DESCRIPTION

[0031] The present application will be described in detail below with reference to the accompanying drawings.

[0032] The preparation method of the present application for a particle size controllable rutile phase nanometer titanium dioxide in Example 1 comprises the following steps:

[0033] S1, 20 mL of anhydrous ethanol with a purity of ≥99.7% and a molecular weight of 46.07 and 20 mL of super-dry acetonitrile with a purity of 99.9% and a molecular weight of 41.05 are put into a reaction vessel, a beaker, for mixing, after complete mixing, 0.287 g of benzoic acid with a purity of 99.5% and a molecular weight of 122.12 is slowly dropped into the mixed solution for water bath reaction, the beaker is placed in a water bath kettle for water bath reaction, the water bath temperature is 25°C, and the stirring environment of 500 r / min is continuously maintained during the process, the stirring time is at least 30 min, until the benzoic acid is completely dispersed in the mixed solution, to obtain system A.

[0034] S2, continue to stir at 500 r / min, and use a pipette to remove 0.5 mL of tetrabutyl titanate (C16 H 36 4 mL of O4Ti was slowly added dropwise to system A for a water bath reaction. The water bath temperature was maintained at 25°C, and the mixture was stirred continuously for 30 minutes to allow benzoic acid and tetrabutyl titanate to react fully until the mixture turned pale yellow, thus obtaining system B. In this step, the reaction process of benzoic acid and tetrabutyl titanate can effectively control the hydrolysis rate of tetrabutyl titanate, thereby ensuring the uniformity of the particles after the reaction.

[0035] S3, first take 80 mL of anhydrous ethanol and 80 mL of ultra-dry acetonitrile and put them into another beaker for mixing. After complete mixing, in a stirring environment of 500 r / min, take 1 mL of deionized water and add it dropwise to the mixture for water bath reaction. The water bath temperature is 25℃ and the stirring time is 30 minutes to make the water evenly distributed in the mixed solution, and obtain system C.

[0036] S4, continue stirring at 500 r / min, quickly pour system C into system B for water bath reaction, at water bath temperature of 25℃, stirring time of 2h, to obtain system D;

[0037] S5, system D is washed, precipitated, and then dried. The dried product is then ground until it has a fine texture to obtain a semi-finished powder. Preferably, the washing includes washing with deionized water and washing with anhydrous ethanol. During washing, system D is first washed once with deionized water, and then washed twice with anhydrous ethanol. After that, the mixture is allowed to stand and precipitate to obtain a white precipitate. The precipitate is then placed in a clean crucible and dried in a vacuum drying oven at a temperature of 60°C for 8 hours. After the precipitate of system D is completely dried, it is ground with a grinder until it becomes a fine powder, which is the semi-finished powder.

[0038] S6. Take the semi-finished powder and pour it into deionized water and stir until the semi-finished powder is completely dispersed in the water. Then add anhydrous oxalic acid and carry out a microwave hydrothermal reaction. After the reaction is completed, the reaction solution is obtained. Specifically, take 40 mL of deionized water and pour it into a microwave hydrothermal reactor. Then weigh 1.0 g of semi-finished powder and 0.1 g of anhydrous oxalic acid (C2H2O4) with a purity of 99.0% and a molecular weight of 90.03. Pour them into the microwave hydrothermal reactor and stir the liquid in the reactor until the semi-finished powder and anhydrous oxalic acid are evenly dispersed in the deionized water. Then start the microwave hydrothermal reactor to carry out the microwave hydrothermal reaction. Set the reaction temperature to 190℃ and the reaction time to 20 min. After the reaction is completed, the reaction solution is obtained.

[0039] S7. The reaction solution was subjected to ultrasonication, washing, centrifugation and drying in sequence to obtain uniform rutile phase nano-titanium dioxide.

[0040] The scanning electron microscope images and XRD diffraction patterns shown in Figs. 1 and 2 are obtained by scanning electron microscope imaging and XRD analysis of the semi-finished product powder and the final product in the present embodiment. Figure 1 The particle conditions in the obtained electron microscope images are analyzed in detail as follows. Figure 2 The average particle size of the semi-finished product powder is 434.66 nm, and the crystal form is amorphous; the average particle size of the final product after the microwave hydrothermal reaction is 204.92 nm, and the crystal form is rutile, which belongs to the rutile phase nanometer titanium dioxide to be obtained in the present application.

[0041] The preparation method of the rutile phase nanometer titanium dioxide with controllable particle size in the present embodiment 2 comprises the following steps:

[0042] S1, 20 mL of anhydrous ethanol with a purity of ≥99.7% and a molecular weight of 46.07 and 20 mL of super-dry acetonitrile with a purity of 99.9% and a molecular weight of 41.05 are put into a reaction vessel, a beaker, for mixing. After complete mixing, 0.287 g of benzoic acid with a purity of 99.5% and a molecular weight of 122.12 is slowly dropped into the mixed solution for water bath reaction in a stirring environment of 500 r / min. The water bath reaction is carried out by placing the beaker in a water bath pot, and the water bath temperature is 25°C. The stirring environment of 500 r / min is continuously maintained during the process, and the stirring time is at least 30 min. Until the benzoic acid is completely dispersed in the mixed solution, system A is obtained.

[0043] S2, continue to slowly drop 4 mL of tetrabutyl titanate (C 16 H 36 O4Ti) with a purity of 99.0% and a molecular weight of 340.32 into system A for water bath reaction in a stirring environment of 500 r / min. The water bath temperature is maintained at 25°C in this step, and the stirring is continuously maintained for 30 min. The benzoic acid and tetrabutyl titanate are fully reacted until the mixed solution is light yellow, and system B is obtained.

[0044] S3, first, 80 mL of anhydrous ethanol and 80 mL of super-dry acetonitrile are put into another beaker for mixing. After complete mixing, 1 mL of deionized water is dropped into the mixed solution for water bath reaction in a stirring environment of 500 r / min. The water bath temperature is 25°C, and the stirring time is 30 min. The water is uniformly distributed in the mixed solution, and system C is obtained.

[0045] S4, continue stirring at 500 r / min, quickly pour system C into system B for water bath reaction, at this time the water bath temperature is 25℃, the stirring time is 2h, and system D is obtained;

[0046] S5, after washing, precipitation and drying of system D, the dried product is ground to have a delicate feeling, and a semi-finished powder is obtained; preferably, the washing includes deionized water washing and anhydrous ethanol washing, in which, first, system D is washed once with deionized water, then system D is washed twice with anhydrous ethanol, and then white precipitate is obtained after standing and precipitation; the precipitate is introduced into a clean crucible and placed in a vacuum drying oven for drying, the drying temperature is set to 60℃, and the drying time is 8h; after the precipitate of system D is completely dried, the precipitate is ground with a grinder until it is ground into a powder with a delicate feeling, that is, a semi-finished powder.

[0047] S6, take the semi-finished powder and pour it into deionized water for stirring until the semi-finished powder is completely dispersed in the water, then add anhydrous oxalic acid for microwave hydrothermal reaction, and obtain a reaction liquid after the reaction; specifically, 50mL of deionized water is poured into a microwave hydrothermal reaction kettle, then 1.5g of semi-finished powder and 0.1g of anhydrous oxalic acid with a purity of 99.0% and a molecular weight of 90.03 are weighed and poured into the microwave hydrothermal reaction kettle, the liquid in the reaction kettle is stirred until the semi-finished powder and the anhydrous oxalic acid are uniformly dispersed in the deionized water, then the microwave hydrothermal reaction instrument is started for microwave hydrothermal reaction, the reaction temperature is set to 190℃, and the reaction time is 20min, and after the reaction is completed, a reaction liquid is obtained.

[0048] S7, the reaction liquid is sequentially subjected to ultrasonic treatment, washing, centrifugation and drying treatment, and a uniform rutile phase nano titanium dioxide is obtained.

[0049] The scanning electron microscope imaging of the semi-finished powder and the final product in this embodiment is used to obtain an electron microscope photograph as shown in Figure 3 After statistical analysis, the average particle size of the semi-finished powder is 421.32nm, and the crystal form is amorphous; the average particle size of the final product after microwave hydrothermal reaction is 252.52nm, and the crystal form is rutile, which belongs to the rutile phase nano titanium dioxide to be obtained in the present application.

[0050] The preparation method of the rutile phase nano titanium dioxide with controllable particle size in the embodiment 3 of the present application comprises the following steps:

[0051] S1, take the purity of ≥ 99.7%, molecular weight of 46.07 anhydrous ethanol 20 mL and the purity of 99.9%, molecular weight of 41.05 super dry acetonitrile 20 mL into the reactor - beaker for mixing, after complete mixing, in the stirring environment of 500 r / min, take the purity of 99.5%, molecular weight of 122.12 benzoic acid 0.4305 g slowly drop into the mixed solution for water bath reaction, water bath reaction is to put the beaker into the water bath, the water bath temperature is 25 DEG C, the stirring environment is continuously kept at 500 r / min during the process, the stirring time is at least 30 min, until the benzoic acid is completely dispersed in the mixed solution, obtain system A.

[0052] S2, continue in the stirring environment of 500 r / min, use the pipette to remove the purity of 99.0%, molecular weight of 340.32 titanium tetrabutoxide (C 16 H 36 O4Ti) 4 mL slowly drop into system A for water bath reaction, the water bath temperature is kept at 25 DEG C in this step, continue stirring for 30 min, make the benzoic acid and titanium tetrabutoxide fully react, until the mixed solution is light yellow, obtain system B.

[0053] S3, first take 80 mL of anhydrous ethanol and 80 mL of super dry acetonitrile into another beaker for mixing, after complete mixing, in the stirring environment of 500 r / min, take 5 mL of deionized water drop into the mixed solution for water bath reaction, the water bath temperature is 25 DEG C, the stirring time is 30 min, make the water uniformly distributed in the mixed solution, obtain system C.

[0054] S4, continue in the stirring environment of 500 r / min, pour system C into system B for water bath reaction, at this time the water bath temperature is 25 DEG C, the stirring time is 2 h, obtain system D;

[0055] S5, after washing, precipitating and drying system D, grind the dried product to have a delicate feeling, obtain the semi-finished powder; preferably, the washing includes deionized water washing and anhydrous ethanol washing, in the washing, first wash system D with deionized water once, then wash system D with anhydrous ethanol twice, and then obtain white precipitate after standing and precipitating; introduce the precipitate into a clean crucible, put it into a vacuum drying oven for drying, set the drying temperature to 60 DEG C, the drying time is 8 hours, after the precipitate of system D is completely dried, grind the precipitate with a grinder until it is ground into a powder with a delicate feeling, which is the semi-finished powder.

[0056] S6, the semi-finished product powder is poured into deionized water for stirring until the semi-finished product powder is completely dispersed in the water, and then anhydrous oxalic acid is added for microwave hydrothermal reaction, and a reaction liquid is obtained; specifically, 40 mL of deionized water is poured into a microwave hydrothermal reaction kettle, and then 1.0 g of the semi-finished product powder and 0.1 g of anhydrous oxalic acid with a purity of 99.0% and a molecular weight of 90.03 (C2H2O4) are weighed and poured into the microwave hydrothermal reaction kettle, the liquid in the reaction kettle is stirred until the semi-finished product powder and the anhydrous oxalic acid are uniformly dispersed in the deionized water, and then the microwave hydrothermal reaction instrument is started for microwave hydrothermal reaction, the reaction temperature is set to 190 DEG C, and the reaction time is 20 min, and after the reaction is completed, the reaction liquid is obtained.

[0057] S7, the reaction liquid is sequentially subjected to ultrasonic treatment, washing, centrifugal treatment and drying treatment, and a uniform rutile phase nano titanium dioxide is obtained.

[0058] After statistical analysis, it is found that the average particle size of the semi-finished product powder is 372.72 nm, and the crystal form is amorphous; the average particle size of the final product after microwave hydrothermal reaction is 287.60 nm, and the crystal form is rutile, which belongs to the rutile phase nano titanium dioxide to be obtained in the application.

[0059] The preparation method of the rutile phase nano titanium dioxide with controllable particle size in the embodiment 4 of the application comprises the following steps:

[0060] S1, 20 mL of anhydrous ethanol with a purity of ≥99.7% and a molecular weight of 46.07 and 20 mL of super-dry acetonitrile with a purity of 99.9% and a molecular weight of 41.05 are poured into a reaction vessel, a beaker, for mixing, after complete mixing, 0.287 g of benzoic acid with a purity of 99.5% and a molecular weight of 122.12 is slowly dropped into the mixed liquid for water bath reaction under a stirring environment of 500 r / min, the beaker is placed in a water bath kettle for water bath reaction, the water bath temperature is 25 DEG C, and the stirring environment of 500 r / min is continuously maintained during the process, and the stirring time is at least 30 min, until the benzoic acid is completely dispersed in the mixed liquid, and system A is obtained.

[0061] S2, continue to stir at 500 r / min, and use a pipette to slowly drop 4 mL of tetrabutyl titanate (C 16 H 36 O4Ti) with a purity of 99.0% and a molecular weight of 340.32 into system A for water bath reaction, the water bath temperature is maintained at 25 DEG C in this step, and the stirring is continuously maintained for 30 min, so that the benzoic acid and the tetrabutyl titanate are fully reacted, until the mixed liquid is light yellow, and system B is obtained.

[0062] S3, first, 80mL of anhydrous ethanol and 80mL of super dry acetonitrile are put into another beaker to mix, after complete mixing, 5mL of deionized water is dropped into the mixed solution to carry out water bath reaction in the stirring environment of 500r / min, the water bath temperature is 25℃, and the stirring time is 30 minutes, so that the water is uniformly distributed in the mixed solution, to obtain system C.

[0063] S4, continue to stir in the environment of 500r / min, quickly pour system C into system B to carry out water bath reaction, at this time the water bath temperature is 25℃, and the stirring time is 2h, to obtain system D.

[0064] S5, after washing, precipitation and drying of system D, the dried product is ground to have a delicate feeling, to obtain a semi-finished powder; preferably, the washing includes deionized water washing and anhydrous ethanol washing, in the washing, first, system D is washed once with deionized water, then system D is washed twice with anhydrous ethanol, and then white precipitate is obtained after standing and precipitation; the precipitate is introduced into a clean crucible and placed in a vacuum drying oven to dry, the drying temperature is set to 60℃, and the drying time is 8 hours, after the precipitate of system D is completely dried, the precipitate is ground with a grinder until it is ground into a powder with a delicate feeling, that is, a semi-finished powder.

[0065] S6, the semi-finished powder is poured into deionized water to stir until the semi-finished powder is completely dispersed in the water, then anhydrous oxalic acid is added to carry out microwave hydrothermal reaction, and a reaction liquid is obtained after the reaction; specifically, 40mL of deionized water is poured into a microwave hydrothermal reaction kettle, then 1.0g of semi-finished powder and 0.1g of anhydrous oxalic acid with a purity of 99.0% and a molecular weight of 90.03 (C2H2O4) are weighed and poured into the microwave hydrothermal reaction kettle, the liquid in the reaction kettle is stirred until the semi-finished powder and the anhydrous oxalic acid are uniformly dispersed in the deionized water, then the microwave hydrothermal reaction instrument is started to carry out microwave hydrothermal reaction, the reaction temperature is set to 190℃, and the reaction time is 20 minutes, after the reaction is completed, the reaction liquid is obtained.

[0066] S7, the reaction liquid is sequentially subjected to ultrasonic treatment, washing, centrifugation and drying treatment, to obtain uniform rutile phase nano titanium dioxide.

[0067] After statistical analysis, the average particle size of the semi-finished powder is 368.93nm, and the crystal form is amorphous; the average particle size of the final product after microwave hydrothermal reaction is 237.07nm, and the crystal form is rutile, which belongs to the rutile phase nano titanium dioxide to be obtained in the application.

[0068] The preparation method of the rutile phase nano titanium dioxide with controllable particle size in the embodiment 5 of the application comprises the following steps:

[0069] S1, take the purity of ≥ 99.7%, molecular weight of 46.07 anhydrous ethanol 20 mL and the purity of 99.9%, molecular weight of 41.05 super dry acetonitrile 20 mL into the reactor - beaker mixing, complete mixing in 500 r / min stirring environment, take the purity of 99.5%, molecular weight of 122.12 benzoic acid 0.4305 g slowly drop into the mixed solution for water bath reaction, water bath reaction is to be placed into the water bath in the beaker, water bath temperature is 25 DEG C, the process continues to keep 500 r / min stirring environment, stirring time is at least 30 min, until the benzoic acid is completely dispersed in the mixed solution, get system A.

[0070] S2, continue in 500 r / min stirring environment, with a pipette to remove the purity of 99.0%, molecular weight of 340.32 titanium tetrabutoxide (C 16 H 36 O4Ti)4 mL slowly drop into system A for water bath reaction, the water bath temperature is kept at 25 DEG C in this step, continue to stir for 30 min, make benzoic acid and titanium tetrabutoxide react fully, until the mixed solution is light yellow, get system B; in this step, due to the reaction process of benzoic acid and titanium tetrabutoxide, the hydrolysis rate of titanium tetrabutoxide can be effectively controlled, and the uniformity of the particles after the reaction is ensured.

[0071] S3, first take 80 mL of anhydrous ethanol and 80 mL of super dry acetonitrile into another beaker for mixing, complete mixing in 500 r / min stirring environment, take 10 mL of deionized water drop into the mixed solution for water bath reaction, water bath temperature is 25 DEG C, stirring time is 30 min, make the water evenly distributed in the mixed solution, get system C.

[0072] S4, continue in 500 r / min stirring environment, quickly pour system C into system B for water bath reaction, the water bath temperature is 25 DEG C at this time, stirring time is 2 h, get system D.

[0073] S5, system D is washed, precipitated and dried, and the dried product is ground to have a delicate feeling, and a semi-finished powder is obtained; preferably, the washing includes deionized water washing and anhydrous ethanol washing, in the washing, first wash system D with deionized water once, then wash system D with anhydrous ethanol twice, and then obtain white precipitate after standing and precipitating; introduce the precipitate into a clean crucible and put it into a vacuum drying oven for drying, set the drying temperature to 60 DEG C, and the drying time is 8 hours, make the precipitate of system D completely dry, and then grind the precipitate with a grinder until it is ground into a powder with a delicate feeling, which is a semi-finished powder.

[0074] S6, pour the semi-finished product powder into deionized water for stirring until the semi-finished product powder is completely dispersed in the water, then add anhydrous oxalic acid for microwave hydrothermal reaction, and obtain a reaction liquid after the reaction; specifically, 25 mL of deionized water is poured into a microwave hydrothermal reaction kettle, then 0.5 g of semi-finished product powder and 0.1 g of anhydrous oxalic acid with a purity of 99.0% and a molecular weight of 90.03 (C2H2O4) are weighed and poured into the microwave hydrothermal reaction kettle, the liquid in the reaction kettle is stirred until the semi-finished product powder and the anhydrous oxalic acid are uniformly dispersed in the deionized water, then the microwave hydrothermal reaction instrument is started for microwave hydrothermal reaction, the reaction temperature is set to 190 DEG C, and the reaction time is 20 min, and the reaction liquid is obtained after the reaction.

[0075] S7, the reaction liquid is sequentially subjected to ultrasonic treatment, washing, centrifugation and drying treatment to obtain uniform rutile phase nano titanium dioxide.

[0076] After statistical analysis, the average particle size of the semi-finished product powder is 314.65 nm, and the crystal form is amorphous; the average particle size of the final product after microwave hydrothermal reaction is 182.34 nm, and the crystal form is rutile, which belongs to the rutile phase nano titanium dioxide to be obtained in the application.

[0077] The preparation method of the rutile phase nano titanium dioxide with controllable particle size in the embodiment 6 of the application comprises the following steps:

[0078] S1, 20 mL of anhydrous ethanol with a purity of ≥99.7% and a molecular weight of 46.07 and 20 mL of super-dry acetonitrile with a purity of 99.9% and a molecular weight of 41.05 are poured into a reaction vessel, a beaker, for mixing, after complete mixing, 0.287 g of benzoic acid with a purity of 99.5% and a molecular weight of 122.12 is slowly dropped into the mixed liquid for water bath reaction under a stirring environment of 500 r / min, the water bath reaction is carried out by placing the beaker in a water bath, the water bath temperature is 25 DEG C, the stirring environment of 500 r / min is continuously maintained during the process, and the stirring time is at least 30 min, until the benzoic acid is completely dispersed in the mixed liquid, to obtain system A.

[0079] S2, continue to stir at 500 r / min, and slowly drop 4 mL of tetrabutyl titanate (C 16 H 36 O4Ti) with a purity of 99.0% and a molecular weight of 340.32 into system A for water bath reaction, the water bath temperature is maintained at 25 DEG C in this step, and the stirring is continuously maintained for 30 min, so that the benzoic acid and the tetrabutyl titanate are fully reacted, until the mixed liquid is light yellow, to obtain system B; in this step, the reaction process of the benzoic acid and the tetrabutyl titanate can effectively control the hydrolysis rate of the tetrabutyl titanate, thereby ensuring the uniformity of the particles after the reaction is completed.

[0080] S3, first take 80 mL of anhydrous ethanol and 80 mL of super dry acetonitrile into another beaker for mixing, after complete mixing, take 10 mL of deionized water drop into the mixed solution for water bath reaction in the stirring environment of 500 r / min, the water bath temperature is 25℃, the stirring time is 30 minutes, make the water evenly distributed in the mixed solution, obtain system C.

[0081] S4, continue to stir in the environment of 500 r / min, quickly pour system C into system B for water bath reaction, at this time the water bath temperature is 25℃, the stirring time is 2h, obtain system D.

[0082] S5, after washing, precipitating and drying system D, grind the dried product until it has a delicate feeling, obtain the semi-finished powder; preferably, the washing includes deionized water washing and anhydrous ethanol washing, during washing, first wash system D with deionized water once, then wash system D with anhydrous ethanol twice, and then obtain white precipitate after standing and precipitating; introduce the precipitate into a clean crucible and put it into a vacuum drying oven for drying, set the drying temperature to 60℃, the drying time is 8 hours, after the precipitate of system D is completely dried, grind the precipitate with a grinder until it is ground into a powder with a delicate feeling, which is the semi-finished powder.

[0083] S6, take the semi-finished powder into deionized water for stirring until the semi-finished powder is completely dispersed in the water, then add anhydrous oxalic acid for microwave hydrothermal reaction, and obtain the reaction liquid after the reaction; specifically, take 40 mL of deionized water into a microwave hydrothermal reaction kettle, then weigh 1.0 g of semi-finished powder and 0.1 g of anhydrous oxalic acid with a purity of 99.0% and a molecular weight of 90.03 (C2H2O4) into the microwave hydrothermal reaction kettle, stir the liquid in the reaction kettle until the semi-finished powder and the anhydrous oxalic acid are uniformly dispersed in the deionized water, then start the microwave hydrothermal reaction instrument for microwave hydrothermal reaction, the reaction temperature is set to 190℃, and the reaction time is 20 min, after the reaction is completed, the reaction liquid is obtained.

[0084] S7, the reaction liquid is sequentially subjected to ultrasonic, washing, centrifugation and drying treatment to obtain uniform rutile phase nano titanium dioxide.

[0085] After statistical analysis, the average particle size of the semi-finished powder is 270.77 nm, and the crystal form is amorphous; the average particle size of the final product after microwave hydrothermal reaction is 179.05 nm, and the crystal form is rutile, which belongs to the rutile phase nano titanium dioxide obtained in the present application.

[0086] The preparation method of the nano-titanium dioxide of the present application is basically identical with that of Example 1, the difference is that in step S1, no benzoic acid is added, the image of the product after SEM scanning is shown in Figure 4 It can be seen that the particle size distribution is not uniform, and the particle size cannot be controlled, which proves that in the preparation method, without the presence of benzoic acid, the hydrolysis of tetrabutyl titanate is too fast, resulting in uneven particle size distribution, and the steric hindrance effect of the benzene ring is lost, causing inevitable agglomeration of titanium dioxide, thus leading to the consequence of uneven particle size distribution.

[0087] The preparation method of the nano-titanium dioxide of the present application is basically identical with that of Example 1, the difference is that in step S3, the amount of deionized water added is 20 mL, the image of the product after SEM scanning is shown in Figure 5 It can be seen that the particle size distribution is not uniform, and the particle size cannot be controlled, which proves that in the preparation method, without the presence of benzoic acid, the hydrolysis of tetrabutyl titanate is too fast, resulting in uneven particle size distribution, and the steric hindrance effect of the benzene ring is lost, causing inevitable agglomeration of titanium dioxide, thus leading to the consequence of uneven particle size distribution.

[0088] The above is a further detailed description of the present application in combination with specific preferred embodiments, and cannot be considered as limiting the specific implementation of the present application to these descriptions. For ordinary skilled persons in the technical field to which the present application belongs, without departing from the concept of the present application, a number of simple deductions or substitutions can be made, which should be considered as falling within the protection scope of the present application.

Claims

1. A method for preparing rutile phase nanosized titanium dioxide with controllable particle size, characterized in that, It comprises the following steps: S1, take absolute ethanol and super dry acetonitrile into the reaction vessel for mixing, after complete mixing, take benzoic acid slowly drop into the mixed solution for water bath reaction in the stirring environment of 500 r / min, until benzoic acid is completely dispersed in the mixed solution, to obtain system A; S2, continue to stir in the stirring environment of 500 r / min, take tetrabutyl titanate slowly drop into system A for water bath reaction, until the mixed solution is light yellow, to obtain system B; S3, first take absolute ethanol and super dry acetonitrile into the reaction vessel for mixing, after complete mixing, take deionized water drop into the mixed solution for water bath reaction in the stirring environment of 500 r / min, to obtain system C; S4, continue to stir in the stirring environment of 500 r / min, quickly pour system C into system B for water bath reaction, to obtain system D; S5, after washing, precipitating and drying system D, grind the dried product to have a delicate feeling, to obtain a semi-finished powder; S6, take the semi-finished powder into deionized water for stirring, until the semi-finished powder is completely dispersed in water, then add anhydrous oxalic acid for microwave hydrothermal reaction, after the reaction is completed, a reaction solution is obtained; S7, the reaction solution is sequentially subjected to ultrasonic, washing, centrifugal and drying treatment, to obtain uniform rutile phase nano titanium dioxide; In the step S1, the volume ratio of the absolute ethanol and super dry acetonitrile solution to the absolute ethanol and super dry acetonitrile solution in the step S3 is 1:4, and the addition ratio of the absolute ethanol to the super dry acetonitrile is 1:1; In the step S3, the volume ratio of the addition amount of the deionized water to the addition amount of the absolute ethanol and the super dry acetonitrile is 1~20:200 The molar ratio of the addition amount of the benzoic acid to the tetrabutyl titanate is 0.05~0.5:

1.

2. The method for preparing the particle size controllable rutile phase nano-titania according to claim 1, characterized in that: The volume ratio of the addition amount of the tetrabutyl titanate to the total addition amount of the absolute ethanol and the super dry acetonitrile is 1:

50.

3. The method of claim 1, wherein the method is characterized by: In the step S1, the stirring time is at least 30 min, and the reaction temperature of the water bath reaction is 25~35℃.

4. The method of claim 1, wherein the method is characterized by: In the step S2, the stirring time is at least 1h, and the reaction temperature of the water bath reaction is 25~35℃.

5. The method of claim 1, wherein the method is characterized by: In the step S3, the stirring time is at least 30 min, and the water bath temperature is 25~35℃.

6. The method of claim 1, wherein the method is characterized by: In the step S4, the stirring time is at least 2h, and the reaction temperature of the water bath reaction is 25~35℃.

7. The method for preparing the rutile phase nano-titania with controllable particle size according to any one of claims 1-6, characterized in that: In the step S6, the mass ratio of the semi-finished powder to the anhydrous oxalic acid is 5~15:1~3; the volume of the deionized water is 25~50mL; the reaction time of the microwave hydrothermal reaction is 20 min, and the reaction temperature is 160~220℃.

8. The method of claim 7, wherein the method is characterized by: In the step S5, the washing includes deionized water washing and absolute ethanol washing, wherein the deionized water washing is once, and the absolute ethanol washing is twice; the drying is carried out by using a vacuum drying box, the drying temperature is 60℃, and the drying time is 8 hours.

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