Fluorescent stilbene biphenyl whitening agent crystal and preparation method thereof

Abstract

The invention belongs to the technical field of fluorescent whitening agents, and particularly relates to a fluorescent stilbene biphenyl fluorescent whitening agent crystal and a preparation method thereof. The X-ray powder diffraction angle 2theta of the crystal is equal to 6.68 degrees, 12.82 degrees, 15.88 degrees, 17.72 degrees, 19.46 degrees, 20.92 degrees and 24.42 degrees, and the X-ray powder diffraction angle 2theta of the crystal is equal to 2theta. The crystal structure is in a rhombic sheet shape. The X-ray powder diffraction angle 2 theta of the crystal is equal to 8.46 degrees, 11.76 degrees, 16.18 degrees, 17.38 degrees, 23.12 degrees and 28.9 degrees; the crystal structure is in a block shape. The X-ray diffraction pattern data of the fluorescent whitening agent CBS with two crystal forms provided by the invention can confirm that the fluorescent whitening agent CBS has different crystal forms. And the crystal morphology is more beneficial to filtering and leaching operation in industrial production, so that a product with higher purity is obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of fluorescent whitening agents, and in particular relates to fluorescent distyryl biphenyl fluorescent whitening agent crystals and a preparation method thereof. Background Art

[0002] Fluorescent whitening agent is a fluorescent dye that whitens through the principle of light compensation. Distyryl biphenyl fluorescent whitening agent (CBS), also known as distyryl biphenyl disulfonate sodium, is a benzene derivative with a single-double bond conjugated structure. It has excellent solubility and light resistance, chlorine bleaching resistance, oxygen bleaching resistance, acid and alkali resistance, and good affinity and diffusion for fibers, which can make fabrics bleach evenly. Therefore, it has become the most recognized fluorescent whitening agent in the global washing industry and is also widely used in papermaking, coatings and other fields. It can be prepared from biphenyl through chloromethylation, esterification, and condensation reactions. The general formula of this type of fluorescent whitening agent is:

[0003]

[0004] In current industrial production, the refined CBS crystals are generally needle-shaped, which is not conducive to filtering operations. After filter pressing and drying, the product is finely broken, causing a large amount of fluorescent whitening agent dust to be suspended in the internal air of the production enterprise's workplace. At the same time, the incomplete solid-liquid separation caused by poor filtering performance also causes some impurities in the liquid to remain in the product, thereby affecting the purity of the product.

[0005] In summary, the crystal form and production process of CBS fluorescent whitening agent in the prior art have many deficiencies, especially in terms of the influence of crystal form on filtration operation and product purity. It is urgent to develop new crystal forms and production processes or methods to solve these problems. Summary of the invention

[0006] The object of the present invention is to provide fluorescent distyryl biphenyl brightener crystals and a preparation method thereof which are more conducive to solid-liquid separation of products, so as to improve separation efficiency and product purity in industrial applications.

[0007] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention is:

[0008] A distyryl biphenyl fluorescent whitening agent crystal, with X-ray powder diffraction angles 2θ=6.68°, 12.82°, 15.88°, 17.72°, 19.46°, 20.92°, and 24.42°; the crystal structure is a rhombus flake.

[0009] A distyryl biphenyl fluorescent whitening agent crystal, with X-ray powder diffraction angles 2θ=8.46°, 11.76°, 16.18°, 17.38°, 23.12°, and 28.9°; the crystal structure is blocky.

[0010] A preparation method of the distyryl biphenyl fluorescent whitening agent comprises the following steps: heating and dissolving a crude product of 4,4'-bis(2-sodium sulfonate styryl)biphenyl (CBS) in a solvent, wherein the heating and dissolving temperature is 60-70°C, cooling the temperature to 40-50°C at a cooling rate of 0.5-1°C / min and maintaining the temperature, and cooling the temperature to 15-20°C at a cooling rate of 1-2°C / min and growing the crystals to obtain distyryl biphenyl fluorescent whitening agent crystals.

[0011] When preparing rhombic plate-like crystals, the solvent is a mixed solvent of water and DMF;

[0012] When preparing bulk crystals, the solvent is a mixed solvent of water and ethanolamine solvent.

[0013] When preparing rhombic plate-like crystals, the weight ratio of water to DMF in the mixed solvent is 1:(1-5);

[0014] When preparing block crystals, the weight ratio of water to ethanolamine solvent in the mixed solvent is 1:(3-7).

[0015] When preparing rhombus plate-like crystals, the mass ratio of crude 4,4'-bis(2-sodium sulfonate styryl)biphenyl (CBS) to solvent is 1:(2-5);

[0016] When preparing block crystals, the mass ratio of crude 4,4'-bis(2-sodium sulfonate styryl)biphenyl (CBS) to the solvent in the solution is 1:(5-10).

[0017] The insulation time is 1 to 2 hours.

[0018] The crystal growing time is 4 to 6 hours.

[0019] Compared with the prior art, the advantages of the present invention are:

[0020] The invention provides two crystal forms of distyryl biphenyl fluorescent whitening agent CBS, which respectively have rhombus flake and block morphologies; the X-ray powder diffraction angles 2θ of the rhombus flake fluorescent whitening agent CBS are 6.68°, 12.82°, 15.88°, 17.72°, 19.46°, 20.92° and 24.42°; the X-ray powder diffraction angles 2θ of the block fluorescent whitening agent CBS are 8.46°, 11.76°, 16.18°, 17.38°, 23.12° and 28.9°.

[0021] The two crystal forms of fluorescent whitening agent CBS provided by the present invention can be confirmed as different crystal forms by X-ray diffraction spectrum data. The crystal morphology is more conducive to filtering and eluting operations in industrial production, thereby obtaining a product with higher purity.

[0022] The preparation method of the present invention is convenient for post-processing of the product by adjusting the crystallization process parameters, can be simply eluted, has regular product particle morphology and high purity, is simple to operate, and is easy for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The X-ray powder diffraction pattern of the diamond-shaped flake fluorescent brightener CBS prepared in Example 1;

[0024] Figure 2 This is a polarizing microscope image of the diamond-shaped flake fluorescent brightener CBS prepared in Example 1;

[0025] Figure 3 The X-ray powder diffraction pattern of the block fluorescent brightener CBS prepared in Example 2;

[0026] Figure 4 This is a polarizing microscope image of the block-shaped fluorescent brightener CBS prepared in Example 2. DETAILED DESCRIPTION

[0027] In order to enable those skilled in the art to further understand the technical solutions and features of the present invention, the present invention will be described in detail below in conjunction with embodiments.

[0028] The radiation source used for X-ray powder diffraction in the embodiments of the present invention is CuK ɑ Radiation, obtained by X-ray diffraction on the powder pattern of the new crystalline form determined in the instrument X'Pert powder diffractometer PANalytical in a closed Anton Paar measurement stage, under the following conditions:

[0029] a. Tube power: 40kV / 40mA

[0030] b. Scanning range 1-50°(2θ)

[0031] c. Step size: 0.02°(2θ)

[0032] d. Each step takes 2 seconds

[0033] e. Room temperature

[0034] Example 1

[0035] Add 100g of 4,4'-bis(2-sodium sulfonate styryl)biphenyl (CBS) to a 500ml crystallization kettle, mix 75g of deionized water with 225g of DMF, pour the mixed solvent into the crystallization kettle, start circulating water bath heating to 60°C, stir at this temperature until the solid is dissolved, and keep warm for half an hour to ensure that the solid is completely dissolved. Cool down to 50°C at a cooling rate of 0.5°C / min, keep warm for 1h, then cool down to 20°C at a cooling rate of 2°C / min, grow crystals for 5h, filter to obtain rhombus-shaped fluorescent whitening agent CBS, X-ray powder diffraction pattern is shown in Figure 1 , polarizing microscope image see Figure 2 .

[0036] Depend on Figure 1 It can be seen that the diamond-shaped flake fluorescent whitening agent CBS prepared in this example has characteristic peaks at diffraction angles 2θ=6.68°, 12.82°, 15.88°, 17.72°, 19.46°, 20.92°, and 24.42°.

[0037] Example 2

[0038] Add 50g of 4,4'-bis(2-sodium sulfonate styryl)biphenyl (CBS) to a 500ml crystallization kettle, mix 75g of deionized water with 225g of ethanolamine solvent, pour the mixed solvent into the crystallization kettle, start circulating water bath heating to 65°C, stir at this temperature until the solid is dissolved, and keep warm for half an hour to ensure that the solid is completely dissolved. Cool down to 50°C at a cooling rate of 0.5°C / min, keep warm for 1.5h, then cool down to 20°C at a cooling rate of 2°C / min, grow crystals for 4h, filter to obtain a block of fluorescent whitening agent CBS, X-ray powder diffraction pattern is shown in Figure 3 , polarizing microscope image see Figure 4 .

[0039] Depend on Figure 3 It can be seen that the block fluorescent whitening agent CBS prepared in this example has characteristic peaks at diffraction angles 2θ=8.46°, 11.76°, 16.18°, 17.38°, 23.12°, and 28.9°.

[0040] Example 3

[0041] The rhombus-shaped flake fluorescent brightener CBS obtained in Example 1 and the needle-shaped fluorescent brightener CBS (prepared according to the method described in Chen Hua's document "Synthesis of Fluorescent Brightener 4,4'-Bis-(2-Sodium Sulfonate Styrene) Biphenyl") were respectively used to prepare a dye bath with an owf of 0.5% in a beaker, with a bath ratio of 1:50, and the temperature was raised to 70°C. Cotton cloth was put in and kept warm for 30 minutes, then taken out, naturally dried, and the whiteness of the cloth sample was tested. The whiteness data of the cotton cloth before and after treatment with the two fluorescent brighteners are as follows:

[0042] Table 1 Whitening effect comparison table of diamond-shaped flake fluorescent brightener CBS and needle-shaped fluorescent brightener CBS prepared in Example 1 after application

[0043]

[0044] As shown in Table 1, after dyeing with the diamond-shaped flake fluorescent brightener CBS prepared in Example 1, the whiteness of the cotton cloth is improved, and the whiteness of the cotton cloth after dyeing is higher than that after dyeing with the needle-shaped fluorescent brightener CBS. This shows that the diamond-shaped flake fluorescent brightener CBS prepared by the present invention has a better fabric whitening effect than the existing needle-shaped fluorescent brightener CBS.

[0045] Example 4

[0046] The block fluorescent brightener CBS obtained in Example 2 and the needle fluorescent brightener CBS (prepared according to the method described in Chen Hua's document "Synthesis of Fluorescent Brightener 4,4'-Bis-(2-Sodium Sulfonate Styrene) Biphenyl") were respectively prepared in a beaker with an owf of 0.5% dye bath, a bath ratio of 1:50, and the temperature was raised to 70°C. Cotton cloth was put into the beaker for 30 minutes of heat preservation, then taken out, and the cloth sample was naturally dried, and the whiteness of the cloth sample was tested. The whiteness data of the cotton cloth before and after treatment with the two fluorescent brighteners are as follows:

[0047] Table 2 Whitening effect comparison table of block fluorescent brightener CBS and needle fluorescent brightener CBS prepared in Example 2 after application

[0048]

[0049] It can be seen from Table 2 that the whiteness of the cotton cloth dyed with the block fluorescent brightener CBS prepared in Example 2 is higher than that dyed with the needle-shaped fluorescent brightener CBS, indicating that the whitening effect of the block fluorescent brightener CBS on the fabric is better than that of the needle-shaped fluorescent brightener CBS.

[0050] It can be seen from the above that the two crystal forms of fluorescent whitening agent CBS provided by the present invention have significantly superior whitening effects compared to the needle-shaped fluorescent whitening agent CBS. At the same time, the rhombic flake and block crystal morphologies are more conducive to filtration and elution operations in industrial production than the needle-shaped ones, thereby obtaining products with higher purity.

Claims

1. A distyryl biphenyl fluorescent brightener crystal, characterized in that: The X-ray powder diffraction angles of the crystals are 2θ=6.68°, 12.82°, 15.88°, 17.72°, 19.46°, 20.92°, and 24.42°; and the crystal structure is rhombic flake-shaped.

2. A distyryl biphenyl fluorescent whitening agent crystal, characterized in that: The X-ray powder diffraction angles of the crystals are 2θ=8.46°, 11.76°, 16.18°, 17.38°, 23.12°, and 28.9°; and the crystal structure is blocky.

3. A method for preparing the distyryl biphenyl fluorescent whitening agent according to claim 1 or 2, characterized in that: The crude product of 4,4'-bis(2-sodium sulfonate styryl)biphenyl (CBS) is heated and dissolved in a solvent at a temperature of 60-70°C, cooled to 40-50°C at a cooling rate of 0.5-1°C / min and kept warm, cooled to 15-20°C at a cooling rate of 1-2°C / min for crystal cultivation, and distyryl biphenyl fluorescent whitening agent crystals are obtained.

4. The preparation method according to claim 3, characterized in that: When preparing rhombic plate-like crystals, the solvent is a mixed solvent of water and DMF; When preparing bulk crystals, the solvent is a mixed solvent of water and ethanolamine solvent.

5. The preparation method according to claim 4, characterized in that: When preparing rhombic plate-like crystals, the weight ratio of water to DMF in the mixed solvent is 1:(1-5); When preparing block crystals, the weight ratio of water to ethanolamine solvent in the mixed solvent is 1:(3-7).

6. The preparation method according to claim 3, characterized in that: When preparing rhombus plate-like crystals, the mass ratio of crude 4,4'-bis(2-sodium sulfonate styryl)biphenyl (CBS) to solvent is 1:(2-5); When preparing block crystals, the mass ratio of crude 4,4'-bis(2-sodium sulfonate styryl)biphenyl (CBS) to the solvent in the solution is 1:(5-10).

7. The preparation method according to claim 3, characterized in that: The insulation time is 1 to 2 hours.

8. The preparation method according to claim 3, characterized in that: The crystal growing time is 4 to 6 hours.

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