CN110358366A - A kind of chemical stain fluorescent ink and preparation method and applications - Google Patents

Abstract

A fluorescent color-changing ink, prepared from dye molecule 2,5-diamino-1,4-dibenzoic acid butyl ester, dye dispersant and solvent, the fluorescent ink is written on natural-color paper, the font appears yellow, and Under the irradiation of 365nm ultraviolet lamp, it emits yellow fluorescence; the color of the font can be changed under the action of ink additives, and the ink additives are applied to the above fonts, and chemical reactions occur in situ on the paper, according to the acylation in the ink additives Different concentrations of reagents generate different new fluorescent substances, and the fonts can show green and blue fluorescence under the irradiation of ultraviolet light. The preparation process of the fluorescent dye 2,5-diamino-1,4-dibenzoate butyl is simple and convenient, and it is yellow fluorescent when written on paper, and reacts rapidly with ink additives. As the concentration of ink additives increases, Under natural light, the font color can gradually change from yellow to green to colorless, and under ultraviolet light, the fluorescent color can gradually change from orange to green to blue.

Description

A chemical color-changing fluorescent ink, preparation method and application thereof

technical field

The invention belongs to the field of fluorescent luminescent materials, in particular to a preparation method of a single benzene ring fluorescent dye and a fluorescent color-changing ink.

Background technique

Anti-counterfeiting fluorescent materials will show bright fluorescent effects after being excited by light waves of a specific wavelength. And when the light source is removed, this glowing behavior stops immediately. With the development of the social market and the needs of commodity anti-counterfeiting, the design of fluorescent anti-counterfeiting materials has developed rapidly in many fields. The existing organic fluorescent small molecule color-changing mechanisms are force-induced, lyochromic, and photochromic.

Under the stimulation of external pressure or mechanical force, mechanochromic fluorescent molecules will reversibly transform their photophysical properties (such as ultraviolet-visible absorption, fluorescence emission, etc.). This transformation is based on the molecular configuration, stacking mode and intermolecular forces of fluorescent molecules that can be transformed under external force stimulation, such as molecular planarization, singlet exciton conversion, crystal-amorphous, and amorphous-crystal. , crystal form-crystal conversion, etc. For example, Araki et al. reported a derivative of pyrene containing four acetamides in 2007. Adding methanol to the chloroform solution of the compound precipitated the compound and formed a white solid with strong blue light emission properties. When the force acts on this Solid, color transition from white to yellow, yellow solid with green fluorescent emission. See: Sagara Y, Mutai T, Yoshikawa I, et al.Material design for piezochromicluminescence: hydrogen-bond-directed assemblies of a pyrene derivative.[J].Journal of the American Chemical Society,2007,129(6):1520- 1. LIU et al. reported carbazole-modified D-π-A type β-diketone difluoride boron complexes TCBM and CBM, which have piezofluorochromic properties. The emission wavelength of CBM red-shifted from 548nm to 572nm under mechanical stimulation, and the emission color changed from yellow to orange. The TCBM with tert-butyl group has obvious piezofluorescent discoloration behavior. The synthesized TCBM sample emits strong green fluorescence with the maximum emission wavelength at 547nm. After grinding, the luminescent color becomes orange with the maximum emission peak at 597nm , redshifted by 50nm. This is due to the steric hindrance effect of the tert-butyl group, which makes the molecules arranged loosely in the crystal and is more sensitive to external stimuli, resulting in high-contrast piezofluorochromic behavior of TCBM. See: LIU M, ZHAI L, SUN J, et al.Multi-color solid-state luminescence of difluoroboronβ-diketonate complexes bearing carbazole with mechanofluorochromism and thermofluorochromism[J]. Dyes Pigm, 2016, 128, 271-278. In 2017, SUN et al. The tert-butyl carbazole modified Schiff base boron difluoride complex TPOB was synthesized. The synthesized crystal can emit yellow fluorescence, and the emission wavelength is at 570nm. After grinding, the emission color becomes orange-red, and the emission wavelength is red-shifted to 590nm. After heating the ground powder, the solid-state luminescence returned to yellow fluorescence, and after grinding again, it turned into orange-red fluorescence again, indicating that TPOB piezofluorescent discoloration is a reversible process. See: SUN J, SUN J, MI W, et al. Self-assembling and piezofluorochromic properties of tert-butylcarbazole-based Schiff bases and the difluoroboron complex[J]. Dyes Pigm, 2017, 136, 633-640.

Lyotropic discoloration is due to the change of the polarity of the solvent substance, resulting in a sharp change in the absorption spectrum or emission spectrum of the organic dye molecule, which in turn induces a change in the color development of the organic fluorescent dye substance solution. Lyochromic fluorescent materials generally have a D-π-A conjugated structure. One or more strong electron-withdrawing groups are introduced into the conjugated molecule, which can greatly increase the electron-withdrawing ability and promote the internal charge transfer of the molecule, resulting in molecular The dipole moment is deflected. Based on the principle of intramolecular charge transfer, by changing the polarity of the solvent, the dipole moment of the molecule in the excited state increases, which is conducive to the generation of lysochromism. Using triphenylamine as the matrix, it is modified to obtain a material with a push-pull electronic structure, which has obvious lyochromic properties. As the degree of molecular conjugation increases, the difference in dipole moment becomes larger, and the lyochromic ability is enhanced. See Gupta V D, Tathe A B, Padalkar V S, et al. Red emitting solid state fluorescent triphenylamine dyes: Synthesis, photo-physical property and DFT study [J]. Dyes&Pigments, 2013, 97(3): 429-439. Meisner Q J et al. The 2-(2'-hydroxyphenyl)benzoxazole molecule was synthesized, and its structure has the properties of intramolecular charge transfer and excited state intramolecular proton transfer. Affected by the molecular structure, there are two structures in the excited state, enol and ketone, and the polarity of the solvent will affect the change of the ground state structure of the molecule, thereby causing the change of the excited state structure. Thus, depending on the medium and the excitation wavelength, the emission of the enol, keto, and anion forms can occur simultaneously in the color ranges of blue, green, and orange/red, respectively. Through reasonable selection of medium and excitation wavelength, the white compound color with CIE coordinates of (0.33,0.33) can be obtained. See: Meisner Q J, Younes A H, Yuan Z, et al. Excitation-Dependent Multiple Fluorescence of a Substituted 2-(2'-Hydroxyphenyl)benzoxazole[J].The journal of physical chemistry.A,2018,122(47):9209 .

Photochromism refers to the chemical reaction of a certain compound in the molecule under the irradiation of light of a certain wavelength, and the molecular structure changes from the A configuration with one color to the B configuration of another color, accompanied by the absorption spectrum of the compound. The change. The B configuration can return to the original A configuration under the irradiation of another wavelength of light or the action of heat. Generally, the A configuration only absorbs in the near ultraviolet region, while the B configuration presents a new absorption peak in the visible region, so the two types will show obviously different colors. Spiropyran and spirooxazine are typical photochromic compounds. Professor Liu Lang's research group designed and synthesized 1,3-diphenyl-4-(3-bromobiphenyl)-5-hydroxypyrazole 4-phenylsemicarbazide, a white powder that will change under 365nm ultraviolet light. It turns into yellow powder. The white powder is very sensitive to light. The yellow form formed after a few minutes of sunlight can be stored in the dark for more than 3 months and is very stable. The yellow powder can be turned back to white after being heated in an oven at 110°C for a few minutes. See: Liu L, Xie X, Jia D, et al.Synthesis and Properties of a Novel Photochromic Compound with Modulated Fluorescence in the Solid State[J].The Journal of Organic Chemistry,2010,75(14):4742-4747.Shao B designed and synthesized a molecular switch of photochromic hydrazine derivatives. There are two isomers 1Z (hydrogen bond closing type) and 1E (hydrogen bond breaking type). When 442nm ultraviolet light irradiates 1Z When in toluene solution, the hydrogen bond breaks to 1E, the maximum ultraviolet absorption shifts from 395nm to 343nm, and the solution changes from light yellow to colorless. It returns to the 1Z state when heated or irradiated with 340nm ultraviolet light. See: Shao B, Baroncini M, Qian H, et al.Solution and Solid-State Emission Toggling of a Photochromic Hydrazone[J].Journal of the American Chemical Society,2018,140(39):12323-12327.

Chemical discoloration refers to the rapid reaction of a fluorescent compound with other non-fluorescent chemical reagents to obtain another new stable fluorescent compound to achieve in-situ color change. Synthesize new fluorescent compounds through chemical color change, which has its own stable and unique structure. Compared with the previous dye molecules: the electronic structure of the system, intramolecular hydrogen bonds, and van der Waals forces are all different, so the performance of color development, ultraviolet light and fluorescence spectrum Both change to achieve chemical discoloration.

Mechanochromism, lyochromism, and photochromism will return to their original state after changes in external pressure, solvent, and light environment, and are reversible. Therefore, these color-changing materials are unstable, and are limited in applications such as commodity anti-counterfeiting. The chemical discoloration behavior is not reversible, and the chemical properties of the product are stable, which is suitable for practical production and application. However, there are few reports that propose the use of chemical color-changing mechanism to solve the problem of unstable performance of fluorescent color-changing materials.

Contents of the invention

The object of the present invention is to solve the problem of instability of the above-mentioned color-changing materials, and provide a chemical color-changing fluorescent ink, a preparation method and its application.

The ink consists of two components, one is a fluorescent dye solution and the other is an active chemical reagent solution. The main component of the fluorescent dye solution is a simple fluorescent substance a, 2,5-diamino-1,4-dibenzoic acid butyl ester. The fluorescent dye is produced by the reaction of dibutyl succinate and sodium hydride to generate dibutyl succinate, and then the product is obtained under the action of ammonium acetate and elemental sulfur. The obtained dye is dissolved in an organic solvent, and a dye dispersant is added to prepare a fluorescent ink. The fluorescent ink is written on the natural color paper, the font appears yellow, and emits yellow fluorescence under the irradiation of a 365nm ultraviolet lamp; while the main component of the other component is an acylating agent without fluorescent activity, which can convert 2,5- Amino acylation in butyl diamino-1,4-dibenzoate, dissolve the acylating reagent in an organic solvent and scribble on the above-mentioned fonts, a chemical reaction occurs in situ on the paper, and different concentrations of acylating reagents are produced The new fluorescent substance b or c, the font can show green or blue fluorescence under the irradiation of ultraviolet light.

Technical scheme of the present invention:

1. Chemical color-changing fluorescent ink

It consists of a dye molecule with a simple structure, that is, a single benzene ring fluorescent material 2,5-diamino-1,4-dibenzoic acid butyl (that is, fluorescent substance a), dye dispersants (SRE-4190, SRE-4029, SRE-48000-60, SRE-4703W, SRE-42000, SRE-4023AX) and organic solvents (chloroform, acetone, dichloromethane, ethyl acetate, tetrahydrofuran, acetonitrile, ethanol, methanol, dimethyl sulfoxide, N, N-dimethyl sulfoxide) together; write with this ink, the font color can change color under the action of ink additives, and the molecular structural formula of the dye is as follows:

The dosage ratio of 2,5-diamino-1,4-dibenzoic acid butyl ester, organic solvent and dye dispersant in the chemical fluorescent color-changing ink is (0.0062-0.0125g): (3-5mL): ( 0-2mL). Ultrasonic to make it evenly dispersed.

Described ink auxiliary agent comprises ink auxiliary agent I and ink auxiliary agent II; Acetic anhydride, propionic anhydride, trifluoroacetic anhydride) and organic solvents (chloroform, acetone, dichloromethane, ethyl acetate, tetrahydrofuran, acetonitrile, ethanol, methanol, petroleum ether, n-hexane) mixed uniformly, acyl The concentration of the acylating reagent is the same as that of the fluorescent substance a in the fluorescent color-changing ink; the ink additive II is uniformly prepared by mixing the acylating reagent and an organic solvent, and the concentration of the acylating reagent is 5-5% of the concentration of the fluorescent substance a in the fluorescent color-changing ink. 50 times.

2. The preparation method of the dye molecule (fluorescent substance a) 2,5-diamino-1,4-dibenzoic acid butyl in the chemical color-changing fluorescent ink, the steps are as follows:

1) Synthesis of dibutyl 2,5-diaminoterephthalate: Add 2-3 equivalents of sodium hydride and 50-150 mL of ether (or methyl tert-butyl ether, N, N-dimethyl methyl formamide, N, N-dimethylacetamide, tetrahydrofuran, ethylene glycol dimethyl ether, ethylene glycol dimethyl ether), then slowly drop 0.1-5mL n-butanol, 5.8g (25m mol, 1 equivalent) dibutyl succinate. Raise the temperature to 40-100°C and react for 4 hours. Quench the reaction with 20-100 mL of water and 3-10 mL of acetic acid (concentrated sulfuric acid, hydrochloric acid, phosphoric acid, nitric acid). The solid product was obtained by suction filtration.

2) Weigh 1.56g (5mmol, 1 equivalent) of the solid obtained in step 1), mix it with 2-10 equivalents of ammonium acetate, and put it into 4-50mL of n-butanol (or N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, ethylene glycol dimethyl ether) at 90-150°C for 8 hours under reflux. After the reaction is complete, 0.4-4.0 equivalents of elemental sulfur is added, and the reaction is heated at 70-150° C. for 10 hours. After cooling, it was suction filtered to obtain an orange-yellow solid product fluorescent substance a, that is, the dye molecule 2,5-diamino-1,4-dibenzoic acid butyl in the chemical color-changing fluorescent ink. The reaction process is as follows:

3. Synthesis of fluorescent substance b

Take 2,5-diamino-1,4-dibenzoic acid butyl 0.308g (1m moL, 1 equivalent), 1-2 equivalents of N,N-diisopropylethylamine dissolved in 10-100mL dichloromethane ( or chloroform, acetonitrile, acetone, ethyl acetate) and stir in an ice bath, take 1.0-2.5 equivalents of an acylating reagent and slowly add it dropwise to the reaction system, and stir at room temperature for 1-6 hours. The reaction liquid was successively washed twice with an equal volume of water, 0.1 mol/L hydrochloric acid, saturated sodium bicarbonate solution, and saturated sodium chloride solution respectively. Dry over anhydrous sodium sulfate. Fluorescent substance b was obtained by column chromatography. The synthetic route is as follows:

4. Synthesis of fluorescent substance c

Take 2,5-diamino-1,4-dibenzoic acid butyl 0.308g (1m moL, 1 equivalent), 1-2 equivalents of N,N-diisopropylethylamine dissolved in 10-100mL dichloromethane ( or chloroform, acetonitrile, acetone, ethyl acetate) and stir in an ice bath, take 2.0-5.0 equivalents of an acylating reagent and slowly add it dropwise to the reaction system, and stir at room temperature for 1-6 hours. The reaction liquid was successively washed twice with an equal volume of water, 0.1 mol/L hydrochloric acid, saturated sodium bicarbonate solution, and saturated sodium chloride solution respectively. Dry over anhydrous sodium sulfate. Fluorescent substance c was obtained by column chromatography. The synthetic route is as follows:

5. Application of chemical color-changing fluorescent ink

1) Preparation of fluorescent ink: Dissolve 2,5-diamino-1,4-dibenzoic acid butyl ester and dye dispersant in an organic solvent and mix evenly, among which 2,5-diamino-1,4-dibenzoic acid The dosage ratio of butyl ester, organic solvent and dye dispersant is (0.0062-0.0125g): (3-5mL): (0-2mL). Ultrasonic to disperse evenly.

2) An application of the fluorescent color-changing ink, using the prepared ink to write on natural-color paper, the font appears yellow under natural light, and emits yellow fluorescence under the irradiation of a 365nm ultraviolet lamp. The emission wavelength was detected at 559nm by a fluorescence spectrophotometer, and the excitation wavelength was set at 375nm.

Use the ink additive I to write on the above-mentioned characters, the fluorescent substance a in the fluorescent color-changing ink reacts with the non-fluorescent active acylating reagent in the ink additive I in situ, and generates the fluorescent substance b in situ (the synthesis process is as described above ), the font turns green under natural light, and emits green fluorescence under 365nm ultraviolet light. The emission wavelength was detected at 493nm and the excitation wavelength was 375nm by a fluorescence spectrophotometer.

Use ink additive II to write on the font, the fluorescent substance a in the fluorescent color-changing ink reacts with the non-fluorescent active acylating reagent in the ink additive II in situ, and generates fluorescent substance c in situ (the synthesis process is as described above) , the font becomes colorless under natural light, and emits blue fluorescence under 365nm ultraviolet light. The emission wavelength was detected at 467nm and the excitation wavelength was 375nm by a fluorescence spectrophotometer.

The invention has the advantages that the fluorescent dye 2,5-diamino-1,4-dibenzoic acid butyl ester has a simple preparation process, excellent fluorescent luminescence performance, solid fluorescent performance, and rapid reaction with ink additives. With the increase of the concentration of ink additives, the font color can gradually change from yellow to green to colorless under natural light, and the fluorescent color can gradually change from orange to green to blue under ultraviolet light, and fluorescent substances b and c can be generated in situ on the paper .

Description of drawings

Fig. 1 is the NMR spectrum of fluorescent substance a, 2,5-dibutyl diaminoterephthalate.

Fig. 2 is the H NMR spectrum of the fluorescent substance b.

Fig. 3 is the H NMR spectrum of the fluorescent substance c.

Fig. 4 is the ultraviolet spectrograms of fluorescent substances a, b, and c.

Fig. 5 is the fluorescence spectrum diagrams of fluorescent substances a, b, and c.

Figure 6 is an application example of fluorescent color-changing ink.

Fig. 7 is a fluorescence spectrum diagram of three fluorescent color fonts of yellow, green and blue.

Fig. 8 is a chromaticity diagram of fluorescent substances a, b, and c.

Detailed ways

Example 1:

A chemical color-changing fluorescent ink, its main components are 2,5-diamino-1,4-dibenzoic acid butyl ester (fluorescent substance a), dye dispersant SRE-4190, acetone mixed evenly to make fluorescent color-changing ink , wherein the dosage ratio of 2,5-diamino-1,4-dibenzoic acid butyl ester, organic solvent and dye dispersant is 0.0125g: 3mL: 2mL.

1. Synthesis of fluorescent dyes

The structure of 2,5-diamino-1,4-dibenzoic acid butyl ester is:

The preparation method of the fluorescent dye is as follows,

1. Synthesis of 2,5-dibutyl diaminoterephthalate (fluorescent substance a), the specific steps are as follows:

1) Dibutyl 2,5-diaminoterephthalate: Take 2.5g of sodium hydride (63m moL, 2.5 equivalents) and 50mL of ether into a 100mL single-necked flask in turn, and stir. 2 mL of n-butanol and 5.8 g (25 m mol, 1 equivalent) of dibutyl succinate were slowly added dropwise in sequence. Connect the condenser tube and the bubbler, program the temperature to 40°C, and stop heating after 4 hours of reaction. The reaction was quenched with 20 mL of water and 5 mL of acetic acid. The solid product was obtained by suction filtration.

2) Weigh 1.56g (5mmol, 1eq) of the solid in step 1), 1.93g (25mmol, 5eq) of ammonium acetate, and 10mL of dimethyl sulfoxide into a 50mL single-necked flask, and heat to reflux at 150°C for 8 hours. Sampling was done to monitor the progress of the reaction. After the reaction was complete, 0.176 g (5.5 mmol, 1.1 equivalent) of elemental sulfur was added, and the temperature was lowered to 100° C. for 10 hours. After the reaction was complete, the heating was stopped, and after cooling, the fluorescent substance a was obtained by suction filtration to obtain an orange-yellow solid product.

Fig. 1 is the proton nuclear magnetic resonance spectrogram of 2,5-diamino-dibutyl terephthalate. The figure shows: ¹ HNMR (400MHz, DCCl ₃ ) δ7.28(s, 1H), 5.07(s, 2H), 4.28(t, J=6.6Hz, 2H), 1.74(dq, J=8.6, 6.7Hz ,2H), 1.52–1.42(m,2H), 0.98(t,J=7.4Hz,3H). It indicated the successful synthesis of 2,5-diamino-1,4-dibenzoic acid butyl ester.

2. Synthesis of fluorescent dye b: Take 0.308g (1m mol, 1 equivalent) of 2,5-diamino-1,4-dibenzoic acid butyl ester, 50mL ethyl acetate, 0.3 N,N-diisopropylethylamine g (2.3mmol, 1.15eq) into a 100mL single-necked bottle, and stirred under an ice bath. Take 1.6 g of acetyl chloride (2 mmol, 1 equivalent) in 5 mL of ethyl acetate, slowly add it dropwise into the reaction system, and stir at room temperature for 3 hours. Post-treatment: The reaction liquid was washed successively with water (50mL×2), 0.1mol/L hydrochloric acid (50mL×2), saturated sodium bicarbonate solution (50mL×2), and saturated sodium chloride solution (50mL×2). Dry over anhydrous sodium sulfate. Fluorescent substance b was obtained by column chromatography.

Figure 2 is the H NMR spectrum of fluorescent dye b. The figure shows: ¹ H NMR (400MHz, DCCl ₃ ) δ10.06(s,1H),8.83(s,1H),7.36(s,1H),5.59(s,2H),4.83(s,2H), 4.37–4.33(m,2H),4.33–4.28(m,2H),1.78(qd,J＝7.4,3.6Hz,4H),1.47(dtd,J＝16.6,7.4,1.9Hz,4H),0.99( td, J=7.4, 4.0Hz, 6H). It indicated that the fluorescent dye b was synthesized.

3. Synthesis of fluorescent dye c: Take 0.308g (1mmol, 1 equivalent) of 2,5-diamino-1,4-dibenzoic acid butyl ester, 50mL ethyl acetate, 0.3 N,N-diisopropylethylamine g (2.3mmol, 1.15eq) into a 100mL single-necked bottle, and stirred under an ice bath. Take 4.8g (6mmol, 3eq) of acetyl chloride in 5mL of ethyl acetate, slowly add it dropwise into the reaction system, and stir at room temperature for 3 hours. Post-treatment: The reaction liquid was washed successively with water (50mL×2), 0.1mol/L hydrochloric acid (50mL×2), saturated sodium bicarbonate solution (50mL×2), and saturated sodium chloride solution (50mL×2). Dry over anhydrous sodium sulfate. Fluorescent substance c was obtained by column chromatography.

Fig. 3 is the proton nuclear magnetic resonance spectrogram of fluorescent dye c. The figure shows: ¹ H NMR (400MHz, DCCl ₃ δ10.56(s, 1H), 9.10(s, 1H), 4.85(s, 2H), 4.39(t, J=6.8Hz, 2H), 1.81(dd , J=8.5, 6.3Hz, 2H), 1.54–1.46(m, 2H), 1.00(t, J=7.4Hz, 3H). It indicated that the fluorescent dye c was synthesized.

Fig. 4 is the ultraviolet spectrograms of fluorescent substances a, b, and c. Test conditions: 4×10 ^-5 mol/L dichloromethane solution of fluorescent substances a, b, and c. It can be seen from FIG. 4 that the ultraviolet absorption wavelengths of fluorescent substances a, b, and c are 434nm, 400nm, and 367nm, respectively. The ultraviolet absorption wavelengths of fluorescent substances a, b, and c are sequentially blue-shifted.

Fig. 5 Fluorescence spectra of fluorescent substances a, b, and c. Test conditions: 4×10 ^-5 mol/L dichloromethane solution of fluorescent substances a, b, and c. The fluorescence emission wavelengths of fluorescent substances a, b, and c are 534nm, 473nm, and 434nm, respectively. Fluorescence wavelengths of fluorescent substances a, b, and c are sequentially blue-shifted.

2. Preparation and application of chemical color-changing fluorescent ink

1. The application of the fluorescent substance a - for the preparation of chemical color-changing fluorescent ink, the method is: weigh 0.0125g 2,5-diamino-1,4-butyl dibenzoate dye and 2mL dye dispersant SRE -4190 was dissolved in 3mL of acetone and dispersed evenly by ultrasonication. Use a brush dipped in ink to write "TUST" on natural-colored paper. The font appears yellow under natural light, and the font emits yellow fluorescence when irradiated with 365nm ultraviolet light (see Figure 6a). It was detected with a fluorescence spectrophotometer that the maximum emission wavelength of solid fluorescence was at 558nm (the excitation wavelength was 375nm, see line a in Figure 7). The fluorescence spectrum of fluorescent substance a on natural paper has a certain red shift compared with that in dichloromethane.

2. Preparation and application of ink additives.

Ink Auxiliary I: Dissolve 0.0016g of acetyl chloride in 5mL of petroleum ether and mix well to prepare a solution of acetyl chloride with a concentration of 8×10 ^-3 moL/L. Dip the ink additive I and write on the above-mentioned font "UST", the font changes from yellow to green under natural light, and emits green fluorescence under the irradiation of a 365nm ultraviolet lamp (see Figure 6b). It was detected with a fluorescence spectrophotometer that the solid fluorescence maximum emission wavelength was at 493nm (the excitation wavelength was 375nm, see line b in Figure 7). It can be concluded that the fluorescent substance a reacts with acetyl chloride in situ to generate the fluorescent substance b.

Ink Auxiliary II: Dissolve 0.016g of acetyl chloride in 5mL of petroleum ether and mix well to prepare an 8×10 ^-2 moL/L solution of acetyl chloride. Dip ink additive II and write on "S", the font changes from green to colorless under natural light, almost invisible, and emits blue fluorescence under the irradiation of 365nm ultraviolet light (see Figure 6c). It was detected with a fluorescence spectrophotometer that the emission wavelength of the solid fluorescence was 467nm (the excitation wavelength was 375nm, see line c in Figure 7). It can be concluded that fluorescent substance a reacts with high concentration acetyl chloride in situ to generate fluorescent substance c.

Figure 6 is an application example of fluorescent color-changing ink. The left picture in Figure 6 a is the picture presented by writing "TUST" with ink, and the font is yellow; the right picture is under the irradiation of ultraviolet light, and the font emits yellow fluorescence. b The picture on the left is the picture presented by scribbling on the "UST" font with ink additive I. The font is green after scribbling; the picture on the right is under the irradiation of ultraviolet light, and the font emits green fluorescence after scribbling. c The picture on the left is the picture presented by scribbling on the "S" font with Ink Auxiliary II. After the scribbling, the font is close to colorless; the picture on the right is under the irradiation of ultraviolet light, and the font emits blue fluorescence after scribbling. dThe picture on the left is the picture of the fourth font "T" written with ink, and the font turns back to yellow after the scribble; the picture on the right is under the irradiation of ultraviolet light, the font emits yellow fluorescence after the scribble. From Figure 6d, it can be seen that under the action of ink and ink additives, the font color sequentially realizes the transformation of yellow, green and colorless under natural light; under the irradiation of ultraviolet light, the transformation of yellow, green and blue fluorescence is realized in sequence; The transformation from fluorescent substance a to fluorescent substance b and then to fluorescent substance c is realized from the molecular level.

Fig. 7 is a graph of fluorescence emission spectra of fonts in three colors of yellow, green and blue. When the excitation wavelength is fixed at 375nm, the maximum emission wavelength of the yellow font is 559nm, the maximum emission wavelength of the green font is 493nm, and the maximum emission wavelength of the colorless font is 467nm. From this solid fluorescence, it can be concluded that the ink additive I is applied to the font written in the ink a to generate the fluorescent substance b, and the ink additive II is applied to the font written in the ink a to generate the fluorescent substance c.

Fig. 8 is a chromaticity diagram of fluorescent substances a, b, and c. From right to left are the fluorescent chromaticity diagrams of fluorescent substances a, b, and c. Visually reflect the fluorescence properties of the compound.

Example 2:

The structural formula of 2,5-diamino-1,4-dibenzoic acid butyl ester is:

The preparation method of the fluorescent dye is as follows,

1. Synthesis of fluorescent substance a:

1) Synthesis of dibutyl 2,5-diaminoterephthalate: Take 2.5g of sodium hydride (63m moL, 2.5 equivalents) and 50mL of N,N-dimethylacetamide into a 100mL single-necked flask in turn, and stir. 3 mL of n-butanol and 5.8 g (25 m mol, 1 equivalent) of dibutyl succinate were slowly added dropwise in sequence. Connect the condenser tube and the bubbler, program the temperature to 80°C, and stop heating after 4 hours of reaction. The reaction was quenched with 20 mL of water and 10 mL of phosphoric acid. The solid product was obtained by suction filtration.

2) Weigh 1.56g (5mmol, 1 equivalent) of the solid in step 1), 3.96g (50mmol, 10 equivalents) of ammonium acetate, and 10mL of N, N-dimethylformamide into a 50mL single-necked flask, and heat to reflux at 100°C for 8 Hour. Sampling point plate was used to monitor the reaction progress. After the reaction was complete, 0.176 g (5.5 mmol, 1.1 equivalent) of elemental sulfur was added, and the temperature was lowered to 90° C. for 10 hours. After the reaction was complete, the heating was stopped, and after cooling, the fluorescent substance a was obtained by suction filtration to obtain an orange-yellow solid product.

2. Synthesis of fluorescent dye b: Take 0.308g (1m mol, 1 equivalent) of 2,5-diamino-1,4-dibenzoic acid butyl ester, 50mL ethyl acetate, 0.3 N,N-diisopropylethylamine g (2.3mmol, 1.15eq) into a 100mL single-necked bottle, and stirred under an ice bath. Take 1.6 g of acetyl chloride (2 mmol, 1 equivalent) in 5 mL of ethyl acetate, slowly add it dropwise into the reaction system, and stir at room temperature for 3 hours. Post-treatment: The reaction liquid was washed successively with water (50mL×2), 0.1mol/L hydrochloric acid (50mL×2), saturated sodium bicarbonate solution (50mL×2), and saturated sodium chloride solution (50mL×2). Dry over anhydrous sodium sulfate. Fluorescent substance b was obtained by column chromatography.

3. Synthesis of fluorescent dye c: Take 0.308g (1mmol, 1 equivalent) of 2,5-diamino-1,4-dibenzoic acid butyl ester, 50mL ethyl acetate, 0.3 N,N-diisopropylethylamine g (2.3mmol, 1.15eq) into a 100mL single-necked bottle, and stirred under an ice bath. Take 4.8g (6mmol, 3eq) of acetyl chloride in 5mL of ethyl acetate, slowly add it dropwise into the reaction system, and stir at room temperature for 3 hours. Post-treatment: The reaction liquid was washed successively with water (50mL×2), 0.1mol/L hydrochloric acid (50mL×2), saturated sodium bicarbonate solution (50mL×2), and saturated sodium chloride solution (50mL×2). Dry over anhydrous sodium sulfate. Fluorescent substance c was obtained by column chromatography.

Example 3:

The application of the fluorescent substance a - for the preparation of chemical color-changing fluorescent ink, the method is: weigh 0.0125g 2,5-diamino-1,4-butyl dibenzoate dye and 0.5mL dye dispersant SRE-4029 Dissolve in 4.5mL of dichloromethane, and ultrasonically disperse it evenly. Use a brush dipped in ink to write "TUST" on natural-colored paper. The font appears yellow under natural light, and the font emits yellow fluorescence when irradiated with 365nm ultraviolet light. The maximum emission wavelength of solid fluorescence is detected at 558nm (excitation wavelength is 375nm) by a fluorescence spectrophotometer.

Example 4:

The application of the fluorescent substance a - for the preparation of chemical color-changing fluorescent ink, the method is: weigh 0.0100g 2,5-diamino-1,4-butyl dibenzoate dye and 0mL dye dispersant SRE-4029 solution In 5mL acetone, ultrasonically disperse it evenly. Use a brush dipped in ink to write "TUST" on natural-colored paper. The font appears yellow under natural light, and the font emits yellow fluorescence when irradiated with 365nm ultraviolet light.

Example 5:

The application of the fluorescent substance a - for the preparation of chemical color-changing fluorescent ink, the method is: weigh 0.0125g 2,5-diamino-1,4-butyl dibenzoate dye and 0.5mL dye dispersant SRE-48000 -60 was dissolved in 4.5mL ethyl acetate, and it was dispersed evenly by ultrasonication. Use a brush dipped in ink to write "TUST" on natural-colored paper. The font appears yellow under natural light, and the font emits yellow fluorescence when irradiated with 365nm ultraviolet light.

Embodiment 6:

Preparation and application of ink additives.

Ink additive I: Dissolve 0.0016g of acetyl chloride in 5mL of n-hexane and mix well to prepare a solution of acetyl chloride with a concentration of 8×10 ^-3 moL/L. Dip ink additive I and scribble on the above-mentioned font "UST", the font changes from yellow to green under natural light, and emits green fluorescence under the irradiation of a 365nm ultraviolet lamp.

Ink Auxiliary II: Dissolve 0.016g of acetyl chloride in 5mL of n-hexane and mix well to prepare an 8×10 ^-2 moL/L acetyl chloride solution. Dip ink additive II and write on the "S", the font changes from green to colorless under natural light, almost invisible, and emits blue fluorescence under the irradiation of 365nm ultraviolet light.

Claims (9)

1. a kind of chemical stain fluorescent ink, it is characterised in that: by a kind of simply single phenyl ring fluorescent material 2 of structure, 5- bis- Amino-Isosorbide-5-Nitrae-dibenzoic acid butyl ester dye molecule that is, fluorescent material a, dye dispersant and organic solvent are collectively constituted, through super Sound is allowed to be uniformly dispersed；It is write with this ink, font color can change color under the action of ink auxiliary agent；Wherein contaminate Expect that molecular structural formula is as follows:

2. chemical stain fluorescent ink according to claim 1, which is characterized in that the organic solvent has to be described Solvent be chloroform, acetone, methylene chloride, ethyl acetate, tetrahydrofuran, acetonitrile, ethyl alcohol, methanol, dimethyl sulfoxide or N, N- dimethyl sulfoxide；Dye dispersant is SRE-4190, SRE-4029, SRE-48000-60, SRE-4703W, SRE-42000 Or SRE-4023AX；2,5- diaminostilbene, 4- dibenzoic acid butyl ester, organic solvent, dye dispersant amount ratio be (0.0062-0.0125g): (3-5mL): (0-2mL).

3. chemical stain fluorescent ink according to claim 1, which is characterized in that the ink auxiliary agent includes that ink helps Agent I and ink auxiliary agent II；Ink auxiliary agent I is uniformly mixed with organic solvent by acylated examination and is formulated, the concentration of acylating reagent and Fluorescent material a concentration is identical in fluorescence color-change ink；Ink auxiliary agent II, be uniformly mixed with organic solvent preparation by acylating reagent and At the concentration of acylating reagent is 5-50 times of fluorescent material a concentration in fluorescence color-change ink.

4. chemical stain fluorescent ink according to claim 3, which is characterized in that the acylating reagent is chloro-carbonic acid- 2,2,2- trichloro ethyl ester, chloroacetic chloride, propionyl chloride, butyl chloride, acetic anhydride, propionic andydride or trifluoroacetic anhydride；The organic solvent For chloroform, acetone, methylene chloride, ethyl acetate, tetrahydrofuran, acetonitrile, ethyl alcohol, methanol, petroleum ether or n-hexane.

5. the dye molecule 2,5- diaminostilbene in a kind of chemical stain fluorescent ink as described in claim 1,4- dibenzoic acid The preparation method of butyl ester, its step are as follows:

1) 2-3 equivalent sodium hydride and 50- the synthesis of 2,5- diamino dibutyl terephthalate: are sequentially added in single-necked flask 0.1-5mL n-butanol, 5.8g that is, 25m moL, the dibutyl succinate of 1 equivalent, heating is then slowly added dropwise in 150mL ether To 40-100 DEG C, after reacting 4hr.With 20-100mL water and 3-10mL acetic acid quenching reaction, suction filtration obtains solid product；

2) the solid 1.56g i.e. 5m mol that step 1) obtains is weighed, the ammonium acetate of 1 equivalent and 2-10 equivalent is mixed into 4-50mL It is heated to reflux 8 hours for 90-150 DEG C in n-butanol.The elemental sulfur of 0-2 equivalent, 70-150 DEG C of heating reaction are added after fully reacting 10 hours.It is filtered after cooling and obtains orange/yellow solid product fluorescent material a, that is, the dye molecule in chemical stain fluorescent ink 2,5- diaminostilbene, 4- dibenzoic acid butyl ester.

6. preparation method according to claim 5, which is characterized in that ether described in step 1) can be substituted for methyl- tert Butyl ether, N, dinethylformamide, N, N- dimethyl acetamide, tetrahydrofuran, glycol dimethyl ether or diethylene glycol two Methyl ether；The acetic acid can be substituted for the concentrated sulfuric acid, hydrochloric acid, phosphoric acid or nitric acid；

N-butanol described in step 2 can be substituted for N, dinethylformamide, N, N- dimethyl acetamide, dimethyl sulfoxide Or diethylene glycol dimethyl ether.

7. a kind of application of the chemical stain fluorescent ink as described in any one of claims 1 to 3, it is characterised in that: with the ink Water writes on unbleached paper, and font is yellow, issues yellow fluorescence under the ultraviolet light of 365nm；It is examined with sepectrophotofluorometer Launch wavelength is measured in 559nm, excitation wavelength 375nm.

8. application according to claim 7, it is characterised in that: write in above-mentioned font with ink auxiliary agent I painting, under natural light Font becomes green by yellow, and the fluorescence of green is issued under the ultraviolet light irradiation of 365nm；It is detected with sepectrophotofluorometer Launch wavelength is in 493nm, excitation wavelength 375nm.

9. application according to claim 7, it is characterised in that: it is write in above-mentioned font with ink auxiliary agent II painting, it is natural Font becomes colourless by yellow under light, and the fluorescence of blue is issued under the ultraviolet grade of 365nm；It is detected with sepectrophotofluorometer Launch wavelength is in 467nm, excitation wavelength 375nm.