Preparation method, product and application of a water-soluble nitrogen-doped titanium dioxide dispersion

Abstract

The invention discloses a preparation method, a product and an application of a water-soluble nitrogen-doped titanium dioxide dispersion liquid. A titanate is added to a short-chain alcohol, and stirred at room temperature to obtain a premix; the premix is added to an acidic aqueous solution, heated to 60-90 °C and stirred for reaction to obtain a titanium dioxide dispersion liquid; the temperature is lowered to 40-45 °C, and a nitrogen source triethylamine is added to the titanium dioxide dispersion liquid, and stirred for reaction to obtain a water-soluble nitrogen-doped titanium dioxide dispersion. The preparation conditions of the nitrogen-doped titanium dioxide dispersion liquid of the invention are mild, without high temperature and high pressure, the production process has high safety and low preparation cost, and the product stability is significantly improved. The obtained product has high transparency and does not precipitate in an aqueous solution environment with pH = 1-14.

Description

Technical Field

[0001] The present invention belongs to the technical field of new materials, and particularly relates to a preparation method, product and application of a water-soluble nitrogen-doped titanium dioxide dispersion liquid. Background Art

[0002] Titanium dioxide (TiO 2 ) has a wide range of applications in cosmetics due to its excellent physical and chemical properties. First of all, titanium dioxide is a physical sunscreen that can reflect ultraviolet rays and protect the skin from UVA and UVB damage. It is widely used in sunscreen creams and other sunscreen products, usually in the form of nanoscale particles to provide effective ultraviolet protection. Secondly, due to its excellent covering power, titanium dioxide is often used as a white pigment to give products an opaque or whitening effect, and is widely used in many fields such as cosmetics (such as foundation, eyeshadow), personal care products (such as toothpaste, soap), and coatings.

[0003] Nitrogen-doped titanium dioxide exhibits higher photoactivity and photostability than titanium dioxide. At the same time, nitrogen-doped titanium dioxide can absorb a wider spectrum. Therefore, nitrogen-doped titanium dioxide has very high application value in the fields of cosmetics, coatings and environmental governance. Currently, nitrogen-doped titanium dioxide is mainly prepared by the high-pressure method or the high-temperature calcination method, and the preparation process has low safety and high production cost. On the other hand, highly stable water-dispersible nitrogen-doped titanium dioxide has rarely been reported. The water-dispersible nitrogen-doped nano-titanium dioxide prepared by the low-temperature hydrothermal method described in the patent with the patent application number 200510011165.3 still requires secondary dispersion during actual use. A visible light-responsive photocatalytic spray described in the patent with the patent application number 201410298480.4 still uses the nitrogen-doped nano-titanium dioxide prepared by the patent with the patent number 200510011165.3 in its preparation. Therefore, the preparation of water-dispersible nitrogen-doped nano-titanium dioxide under normal pressure and low temperature is still a challenging task. Summary of the Invention

[0004] The purpose of this part is to outline some aspects of the embodiments of the present invention and briefly introduce some preferred embodiments.

[0005] As one aspect of the present invention, the present invention provides a preparation method of a water-soluble nitrogen-doped titanium dioxide dispersion liquid, which includes the following steps,

[0006] (1) Adding a titanate ester to a short-chain alcohol and stirring at room temperature to obtain a premix; the titanate ester includes tetrabutyl titanate;

[0007] (2) Adding the premix to an acidic aqueous solution, heating to 60-90 °C and stirring for reaction to obtain a titanium dioxide dispersion liquid;

[0008] (3) Cool down to 40 - 45 °C and add the nitrogen source triethylamine to the titanium dioxide dispersion obtained in step (2), and stir and react to obtain a water-soluble nitrogen-doped titanium dioxide dispersion.

[0009] A preferred embodiment of the preparation method of the water-soluble nitrogen-doped titanium dioxide dispersion of the present invention: In step (2), the acidic aqueous solution is a hydrochloric acid aqueous solution, and the mass concentration of the brine aqueous solution is 0.6 - 3%.

[0010] A preferred embodiment of the preparation method of the water-soluble nitrogen-doped titanium dioxide dispersion of the present invention: In step (1), the short-chain alcohol includes one or more of methanol, ethanol, propanol, or butanol.

[0011] A preferred embodiment of the preparation method of the water-soluble nitrogen-doped titanium dioxide dispersion of the present invention: In step (1), the mass ratio of titanate to short-chain alcohol is 0.3 - 0.7:1.

[0012] A preferred embodiment of the preparation method of the water-soluble nitrogen-doped titanium dioxide dispersion of the present invention: In step (1), the premix obtained by stirring at room temperature is stirred at 200 - 800 r / min for 0.1 - 2 hours.

[0013] A preferred embodiment of the preparation method of the water-soluble nitrogen-doped titanium dioxide dispersion of the present invention: In step (2), the mass ratio of the premix to the acidic aqueous solution is 0.1 - 0.2:1.

[0014] A preferred embodiment of the preparation method of the water-soluble nitrogen-doped titanium dioxide dispersion of the present invention: In step (2), the stirring reaction is carried out at 200 - 800 r / min for 1 - 5 h.

[0015] A preferred embodiment of the preparation method of the water-soluble nitrogen-doped titanium dioxide dispersion of the present invention: In step (3), the mass ratio of triethylamine to the titanium dioxide dispersion is 0.01 - 0.05:1; the stirring reaction is carried out at 200 - 800 r / min for 2 - 24 hours.

[0016] Advantages of the present invention: Compared with the prior art, the preparation conditions of the nitrogen-doped titanium dioxide dispersion of the present invention are mild, without high temperature and high pressure, the production process has high safety, low preparation cost, and the product stability is significantly improved. The obtained product has high transparency and will not flocculate in an aqueous solution environment with pH = 1 - 14. Description of the Drawings

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Among them:

[0018] Figure 1XRD pattern of nitrogen-doped titanium dioxide in Example 1.

[0019] Figure 2 Antibacterial effect of the product in Example 1.

[0020] Figure 3 Antibacterial effect of the titanium dioxide dispersion in Comparative Example 7.

[0021] Figure 4 Antibacterial effect of the supernatant of the product in Comparative Example 5.

[0022] Figure 5 Antibacterial effect of the supernatant of the product in Comparative Example 6.

[0023] Figure 6 Product photos of Example 1 and Comparative Examples 1-6. Detailed implementation manners

[0024] To make the above objects, features and advantages of the present invention more obvious and understandable, the following specific embodiments are used to make a detailed description of the specific implementation manners of the present invention.

[0025] Example 1:

[0026] (1) Add 4.0 g of tetrabutyl titanate to 10 g of ethanol and stir for 1 hour at 500 r / min to obtain a premix.

[0027] (2) Add 1.8 g of concentrated hydrochloric acid with a mass concentration of 37% to 100 g of deionized water and stir evenly to obtain a hydrochloric acid solution.

[0028] (3) Add the premix prepared in step (1) to the hydrochloric acid solution prepared in step (2), heat to 80 °C while stirring at 300 r / min, and react for 2 hours to obtain a titanium dioxide dispersion.

[0029] (4) Cool the titanium dioxide dispersion obtained in step (3) to 40 °C, then add 1.5 g of triethylamine thereto, and react for 10 h under stirring at 300 r / min to prepare a water-soluble nitrogen-doped titanium dioxide dispersion.

[0030] Comparative Example 1:

[0031] The difference between Comparative Example 1 and Example 1 is only that 0.5 g of concentrated hydrochloric acid is used instead of 1.8 g of concentrated hydrochloric acid in step (2), and other conditions are the same as those in Example 1.

[0032] Experimental result: Instead of obtaining a blue transparent water-soluble nitrogen-doped titanium dioxide dispersion, a milky white product with a large amount of white precipitate is obtained.

[0033] Comparative Example 2:

[0034] The difference between Comparative Example 2 and Example 1 lies only in step (4). The titanium dioxide dispersion obtained in step (3) was cooled to 60 °C, 1.5 g of triethylamine was added thereto, and the reaction was carried out for 10 h under stirring conditions of 300 r / min. Other conditions were the same as those in Example 1.

[0035] Experimental results: It was impossible to prepare a transparent and blue water-soluble nitrogen-doped titanium dioxide dispersion. Instead, a translucent product containing white precipitate was obtained. It is speculated that the rapid decomposition of triethylamine may be caused by the relatively high temperature.

[0036] Comparative Example 3:

[0037] The difference between Comparative Example 3 and Example 1 is only that 1.5 g of triethylamine was changed to 0.8 g of triethylamine in step (4), and other conditions were the same as those in Example 1.

[0038] Experimental results: It was impossible to prepare a transparent and blue water-soluble nitrogen-doped titanium dioxide dispersion. Instead, a translucent product containing white precipitate was obtained. This is because insufficient surface amino modification was caused by the relatively small amount of triethylamine.

[0039] Comparative Example 4:

[0040] (1) 4.0 g of tetrabutyl titanate was added to 10 g of ethanol, and the mixture was stirred for 1 hour under the condition of 500 r / min to obtain a premix;

[0041] (2) 1.5 g of triethylamine was added to the premix prepared in step (1), and the reaction was carried out for 10 h under stirring conditions of 300 r / min to obtain a nitrogen-doped pre-hydrolyzed product;

[0042] (3) 1.8 g of concentrated hydrochloric acid (mass concentration 37%) was added to 100 g of deionized water, and the mixture was stirred evenly to obtain a hydrochloric acid solution;

[0043] (4) The nitrogen-doped pre-hydrolyzed product prepared in step (2) was added to the hydrochloric acid solution prepared in step (3), and the mixture was heated to 80 °C while stirring at 300 r / min, and the reaction was carried out for 2 hours to obtain a nitrogen-doped titanium dioxide product.

[0044] Experimental results: It was impossible to prepare a transparent and blue water-soluble nitrogen-doped titanium dioxide dispersion. Instead, a product containing white precipitate was obtained. Adding triethylamine first would result in a relatively large particle size of the product.

[0045] Comparative Example 5:

[0046] The difference between Comparative Example 5 and Example 1 is that tetrabutyl titanate was changed to titanium tetrachloride, and other conditions were the same as those in Example 1.

[0047] Experimental results: It was impossible to prepare a transparent and blue water-soluble nitrogen-doped titanium dioxide dispersion. Instead, a product containing a large amount of white precipitate was obtained.

[0048] Comparative Example 6:

[0049] The difference between Comparative Example 6 and Example 1 is that triethylamine was replaced with ammonia water, and other conditions were the same as those in Example 1.

[0050] Experimental results: It was impossible to prepare a transparent and blue water-soluble nitrogen-doped titanium dioxide dispersion. Instead, a product containing a large amount of white precipitate was obtained. Ammonia water could not effectively perform surface modification, and the particle size of the titanium dioxide obtained in the experiment was very large.

[0051] The appearance of the products obtained in Example 1 and Comparative Examples 1 - 6 and the stability test results of the product of Example 1 are shown in Table 1.

[0052] Stability test conditions:

[0053] A certain amount of the sample was placed in a sample bottle, adjusted to different pH values, sealed and stored at a high temperature (50 °C) for 3 months to investigate its stability.

[0054] Comparative Example 7:

[0055] (1) 4.0 g of tetrabutyl titanate was added to 10 g of ethanol and stirred at 500 r / min for 1 hour to obtain a premix;

[0056] (2) 1.8 g of concentrated hydrochloric acid with a mass concentration of 37% was added to 100 g of deionized water and stirred evenly to obtain a hydrochloric acid solution;

[0057] (3) The premix prepared in step (1) was added to the hydrochloric acid solution prepared in step (2), and the mixture was heated to 80 °C while stirring at 300 r / min for 2 hours to obtain a titanium dioxide dispersion.

[0058] The antibacterial effect tests of the product of Example 1 and the products of Comparative Examples 5, 6, and 7 are shown in Figures 2 to 5 .

[0059] Comparative Example 8:

[0060] (1) 4.0 g of tetraethyl titanate was added to 10 g of ethanol and stirred at 500 r / min for 1 hour to obtain a premix;

[0061] (2) 1.8 g of concentrated hydrochloric acid with a mass concentration of 37% was added to 100 g of deionized water and stirred evenly to obtain a hydrochloric acid solution;

[0062] (3) Add the premix prepared in step (1) to the hydrochloric acid solution prepared in step (2), heat it to 80 °C with stirring at 300 r / min, and react for 2 hours to obtain a titanium dioxide dispersion;

[0063] (4) Cool the titanium dioxide dispersion obtained in step (3) to 40 °C, then add 1.5 g of triethylamine thereto, and react for 10 h under stirring at 300 r / min to prepare a water-soluble nitrogen-doped titanium dioxide dispersion.

[0064] Experimental results: White precipitates were formed in the prepared water-soluble nitrogen-doped titanium dioxide dispersion. The possible reason is that the hydrolysis reaction of tetraethyl orthotitanate is relatively violent.

[0065] Comparative Example 9:

[0066] (1) Add 4.0 g of isopropyl titanate to 10 g of ethanol, and stir for 1 hour at 500 r / min to obtain a premix;

[0067] (2) Add 1.8 g of concentrated hydrochloric acid with a mass concentration of 37% to 100 g of deionized water, and stir evenly to obtain a hydrochloric acid solution;

[0068] (3) Add the premix prepared in step (1) to the hydrochloric acid solution prepared in step (2), heat it to 80 °C with stirring at 300 r / min, and react for 2 hours to obtain a titanium dioxide dispersion;

[0069] (4) Cool the titanium dioxide dispersion obtained in step (3) to 40 °C, then add 1.5 g of triethylamine thereto, and react for 10 h under stirring at 300 r / min to prepare a water-soluble nitrogen-doped titanium dioxide dispersion.

[0070] Experimental results: The transparency of the prepared water-soluble nitrogen-doped titanium dioxide dispersion is significantly lower than that of Example 1. The possible reason is that the hydrolysis rate of isopropyl titanate is relatively fast.

[0071] Antibacterial test method:

[0072] Inoculate Malassezia furfur into 200 mL of liquid medium, culture it at 37 °C for 24 h, and culture it overnight on a shaker at 220 r / min. The bacterial solution is reserved. Pour about 20 mL of plate medium into a sterilized plate, let it stand horizontally and solidify. Spread Malassezia furfur evenly on the surface of the solid medium. Place a sterilized Oxford cup on the inoculated medium, and then add 100 μL of the sample solution into the Oxford cup. Place two Oxford cups in each medium and perform two parallel experiments with replicates. Then place it in an incubator at 37 °C and 60% humidity for 48 h, and observe the antibacterial situation.

[0073] Table 1

[0074]

[0075] Figure 1 XRD spectrum of the product of Example 1. Figure 2 Antibacterial effect of the product of Example 1, Figure 2 The diameters of the antibacterial zones on the left and right sides are 19.8 mm and 16.97 mm respectively. Figure 3 Antibacterial effect of the titanium dioxide dispersion of Comparative Example 7, Figure 3 The diameters of the antibacterial zones on the left and right sides are 10.53 mm and 6.57 mm respectively. Figure 4 Antibacterial effect of the supernatant of the product of Comparative Example 5, Figure 4 The diameters of the antibacterial zones on the left and right sides are 12.76 mm and 10.9 mm respectively. Figure 5 Antibacterial effect of the supernatant of the product of Comparative Example 6, Figure 5 The diameters of the antibacterial zones on the left and right sides are 10.0 mm and 9.03 mm respectively. Figure 6 Product photos of Example 1 and Comparative Examples 1-6.

[0076] It should be noted that the above examples are only used to illustrate the technical solutions of the present invention and are not restrictive. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered by the scope of the claims of the present invention.

Claims

1. A method for preparing a water-soluble nitrogen-doped titanium dioxide dispersion, characterized in that: The following steps are included: (1) Adding titanate to short-chain alcohol and stirring at room temperature to obtain a premix; (2) adding the premix into an acidic aqueous solution, heating to 60-90° C. and stirring to react, thereby obtaining a titanium dioxide dispersion; (3) cooling to 40° C. and adding nitrogen source triethylamine to the titanium dioxide dispersion obtained in step (2), stirring and reacting to obtain a water-soluble nitrogen-doped titanium dioxide dispersion; In step (2), the acidic aqueous solution is a hydrochloric acid aqueous solution, and the mass concentration of the hydrochloric acid aqueous solution is 0.6-3%; In step (1), the titanate is tetrabutyl titanate; In step (3), the mass ratio of triethylamine to titanium dioxide dispersion is 0.01-0.05:1; In step (2), the mass ratio of the premix to the acidic aqueous solution is 0.1-0.2:

1.

2. The method for preparing a water-soluble nitrogen-doped titanium dioxide dispersion according to claim 1, characterized in that: In step (1), the short-chain alcohol includes one or more of methanol, ethanol, propanol or butanol.

3. The method for preparing a water-soluble nitrogen-doped titanium dioxide dispersion according to claim 1 or 2, characterized in that: In step (1), the mass ratio of titanate to short-chain alcohol is 0.3-0.7:

1.

4. The method for preparing a water-soluble nitrogen-doped titanium dioxide dispersion according to claim 1 or 2, characterized in that: In step (1), the stirring at room temperature to obtain the premix is ​​performed at 200-800 r / min for 0.1-2 hours.

5. The method for preparing a water-soluble nitrogen-doped titanium dioxide dispersion according to claim 1 or 2, characterized in that: In step (2), the stirring reaction is carried out at 200-800 r / min for 1-5 h.

6. The method for preparing a water-soluble nitrogen-doped titanium dioxide dispersion according to claim 1 or 2, characterized in that: In step (3), the stirring reaction is carried out at 200-800 r / min for 2-24 hours. 7 . The water-soluble nitrogen-doped titanium dioxide dispersion prepared by the method for preparing the water-soluble nitrogen-doped titanium dioxide dispersion according to claim 1 .

8. Use of the water-soluble nitrogen-doped titanium dioxide dispersion prepared by the method for preparing the water-soluble nitrogen-doped titanium dioxide dispersion according to claim 1 in cosmetics, coatings or environmental management.

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