Phenoxazine dye intermediate, dye precursor, dye and preparation method thereof

Abstract

The invention relates to a phenoxazine dye intermediate, a dye precursor, a dye and a preparation method thereof, and belongs to the technical field of dyes. According to the phenoxazine type dye, the phenoxazine intermediate is used as a dye matrix, cyanuric chloride and genipin double active groups are grafted, and the phenoxazine type dye intermediate has excellent color light stability, high color development intensity and bright color light and can dye fibers in supercritical fluid. An iridoid structure of genipin reacts with amino groups on protein fibers, and a fiber-dye-color trinity is generated in the dyeing process. The phenoxazine dye does not need to be applied to water and other dyeing assistants in the dyeing process, the dyeing mode is novel and special, the dyeing process is green and environment-friendly, the dye is friendly to equipment, and the phenoxazine dye has a good application prospect in the aspect of supercritical CO2 dyeing.

Description

Technical Field

[0001] The invention belongs to the technical field of dyes, and in particular relates to a phenoxazine dye intermediate, a dye precursor, a dye and a preparation method thereof. Background Art

[0002] Supercritical CO2 fluid technology turns CO2 gas into a supercritical state under high temperature and high pressure conditions, replacing the water medium to dye and functionally finish textiles under the action of various dyes or auxiliaries. No drying is required after dyeing, which solves the problem of consuming a large amount of water resources and heat energy in the printing and dyeing process (see literature: Banchero M. Recent advances in supercritical fluid dyeing [J]. Coloration Technology, 2020, 136 (4): 317-335.).

[0003] In supercritical CO2 fluid, single dye molecules show excellent diffusion efficiency, and their diffusion rate significantly exceeds that in conventional aqueous solution environment, which effectively improves dyeing efficiency. The samples dyed with SCF-CO2 are evenly colored, and the effect is comparable to the traditional water bath dyeing method. Among them, the dyeing of polyester fibers with disperse dyes in supercritical CO2 fluid has achieved good results, and several active disperse dyes have been studied to successfully dye cellulose fibers, but the variety of active disperse dyes for protein fibers is very small. Protein fibers have a wide range of performance in life, and it is very necessary to develop a supercritical CO2-specific protein fiber active disperse dye (see literature: Zhu WW, Long JJ, Shi MW. Resveratrol-Loaded Diacetate Fiber by Supercritical CO2 Fluid Assisted Impregnation [J]. Materials, 2022, 15 (16): 797-804.).

[0004] Currently, there are relatively few types of active disperse dyes that can be used in supercritical CO2. Generally, azo or anthraquinone structures are used as dye matrices, and s-triazine, vinyl sulfone and bromoacrylamide are used as active groups to synthesize active disperse dyes. Azo active disperse dyes are usually suitable for preparing light-colored dyes, such as orange, yellow and other similar bright colors. Anthraquinone active disperse dyes tend to produce darker colors, especially blue-green tones, and are often more expensive to produce. In addition, these two types of active disperse dyes have poor color fastness after dyeing protein fibers, which greatly limits their application.

[0005] Therefore, for protein fibers, the preparation of non-azo heterocyclic reactive disperse dyes to obtain bright and intense color performance is still of great market value. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a phenoxazine dye intermediate, a dye precursor, a dye and a preparation method thereof. The oxazine structure contains heteroatoms such as N and O, has high color intensity and excellent heat resistance, and can be used as a dye intermediate. In order to improve the dyeing performance of protein fibers, a cyanuric chloride group is grafted on the molecular structure to form a dye precursor, and then a genipin group is grafted to form an active disperse dye. Due to its own low polarity and the effect of active groups, phenoxazine dyes can dye wool, cashmere, silk and other fibers in supercritical CO2 fluid.

[0007] The first object of the present invention is to provide a phenoxazine dye intermediate, the structure of which is shown in Formula III:

[0008]

[0009] Wherein, X = Br, Cl, F or NO2;

[0010] Y=OH, NH2 or NHR, R=CH3 or CH2CH3.

[0011] The second object of the present invention is to provide a method for preparing the phenoxazine dye intermediate, comprising the following steps: reacting a compound of formula I and a compound of formula II in water under the action of an oxidant to obtain a phenoxazine dye intermediate of formula III;

[0012] Wherein, the structural formula of formula I-formula III is as follows:

[0013]

[0014] Wherein, X = Br, Cl, F or NO2;

[0015] Y=OH, NH2 or NHR, R=CH3 or CH2CH3.

[0016] In one embodiment of the present invention, the molar ratio of the compound of formula I to the compound of formula II is 1:(1-3).

[0017] In one embodiment of the present invention, the oxidant is selected from one or more of sodium periodate, potassium permanganate, potassium persulfate, sodium persulfate and ferric chloride.

[0018] In one embodiment of the present invention, the pH of the reaction is 9-11, the temperature is 20°C-40°C, and the time is 30min-90min.

[0019] In one embodiment of the present invention, the pH regulator is sodium carbonate.

[0020] The third object of the present invention is to provide a phenoxazine dye precursor, the structure of which is shown in Formula V:

[0021]

[0022] Wherein, X = Br, Cl, F or NO2;

[0023] Y=OH, NH2 or NHR with one H atom removed, R=CH3 or CH2CH3;

[0024] Z=Cl or F.

[0025] The fourth object of the present invention is to provide a method for preparing the phenoxazine dye precursor, comprising the following steps: reacting the phenoxazine dye intermediate of formula III and the compound of formula IV in a solvent to obtain a phenoxazine dye precursor of formula V;

[0026] Wherein, the structural formula of formula IV-formula V is as follows:

[0027]

[0028] Wherein, X = Br, Cl, F or NO2;

[0029] Y=OH, NH2 or NHR with one H atom removed, R=CH3 or CH2CH3;

[0030] Z=Cl or F.

[0031] In one embodiment of the present invention, the molar ratio of the phenoxazine dye intermediate of formula III to the compound of formula IV is 1:(1-3).

[0032] In one embodiment of the present invention, the pH of the reaction is 9-11, the temperature is 0°C-16°C, and the time is 18h-26h.

[0033] In one embodiment of the present invention, the pH regulator is sodium carbonate.

[0034] A fifth object of the present invention is to provide a phenoxazine dye, the structure of which is shown in Formula VI:

[0035]

[0036] Wherein, X = Br, Cl, F or NO2;

[0037] Y=OH, NH2 or NHR with one H atom removed, R=CH3 or CH2CH3;

[0038] Z=Cl or F.

[0039] The sixth object of the present invention is to provide a method for preparing the phenoxazine dye, comprising the following steps: the phenoxazine dye precursor of formula V and genipin react in a solvent to obtain a phenoxazine dye of formula VI.

[0040] In one embodiment of the present invention, the pH of the reaction is 9-11, the temperature is 32° C.-48° C., and the time is 10 h-18 h.

[0041] In one embodiment of the present invention, the pH regulator is sodium carbonate.

[0042] The technical solution of the present invention has the following advantages over the prior art:

[0043] (1) The phenoxazine dye of the present invention is prepared from a phenoxazine dye precursor and genipin. The phenoxazine dye intermediate is a conjugated cyclic structure containing heteroatoms such as N and O, and has high color intensity and excellent heat resistance. The phenoxazine dye precursor is a cyanuric chloride group grafted on the phenoxazine ring. It not only has the excellent performance of the phenoxazine dye intermediate, but also the introduced cyanuric chloride group is an excellent active group that can undergo nucleophilic substitution reaction with the fiber, so that the dye is firmly attached to the fiber. The phenoxazine dye precursor obtained in this way can be used as a dye precursor and can also be used as a separate active disperse dye. Genipin, as a green and environmentally friendly natural dye, has excellent dyeing effect on protein fibers.

[0044] (2) The active groups of the phenoxazine dye of the present invention are fixed to the protein fiber through a nucleophilic substitution reaction, and the iridoid structure of genipin reacts with the amino group on the protein fiber, and the dyeing process produces a trinity of fiber-dye-color. The phenoxazine dye does not need to be applied with water or other dyeing auxiliaries during the dyeing process, the dyeing method is novel and special, the dyeing process is green and environmentally friendly, and is equipment-friendly, and has good application prospects in supercritical CO2 dyeing.

[0045] (3) The phenoxazine dye of the present invention uses phenoxazine as a matrix and contains two active groups, cyanuric chloride and genipin. Due to the low polarity of the dye itself and the activity of the active group, when dyeing protein fibers in a supercritical CO2 fluid system, the dye can not only dissolve smoothly in the supercritical fluid, but also undergo nucleophilic substitution reaction with the amino group in the protein to form a new conjugated system to produce color. It can be used as a special dye for protein in a supercritical CO2 system, adding to the variety of active disperse dyes and solving the problem of limited dyeing of protein fibers in a supercritical dyeing system.

[0046] (4) The molecular structure of the phenoxazine dye of the present invention contains elements such as nitrogen and sulfur. Such a conjugated system enhances the color development performance of the dye, making it show higher color saturation and brightness.

[0047] (5) The preparation method described in the present invention is simple to operate, easy to control, and has a high reaction conversion rate. The obtained phenoxazine-type active disperse dyes are bright in color, have good directness to fibers, have stable color light, and the two active groups are more firmly bound to the fibers. It has broad application prospects in supercritical CO2 dyeing. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments of the present invention in conjunction with the accompanying drawings, wherein:

[0049] Figure 1 is a Fourier infrared spectrum of the phenoxazine dye intermediate of Example 1 in Test Example 1 of the present invention;

[0050] Figure 2 This is a Fourier infrared spectrum of the phenoxazine dye precursor of Example 2 in Test Example 1 of the present invention;

[0051] Figure 3 is a Fourier transform infrared spectrum of the phenoxazine dye of Example 3 in Test Example 1 of the present invention;

[0052] Figure 4 The UV-visible absorption spectra of the phenoxazine dye intermediate, the phenoxazine dye precursor and the phenoxazine dye in Test Example 2 of the present invention;

[0053] Figure 5 This is a diagram showing the actual effects of different dyeing samples of phenoxazine dyes in supercritical CO2 in Test Example 3 of the present invention;

[0054] Figure 6 3 is the K / S curve of different dyeing samples of phenoxazine dyes in supercritical CO2 in Test Example 3 of the present invention. DETAILED DESCRIPTION

[0055] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. It should be understood that the specific embodiments are only used to explain the present invention, but the embodiments are not intended to limit the present invention.

[0056] In the present invention, unless otherwise explained, technical and scientific terms used in the present invention have the same meanings as commonly understood by those skilled in the art to which the present invention belongs.

[0057] In the present invention, unless otherwise stated, the term "and / or" used in the present invention includes any and all combinations of one or more of the associated listed items.

[0058] In the present invention, unless otherwise stated, the experimental methods used in the embodiments of the present invention are conventional methods unless otherwise stated, and the materials, reagents, etc. used are all commercially available unless otherwise stated.

[0059] Example 1

[0060] The phenoxazine dye intermediate of the present invention and the preparation method thereof specifically comprise the following steps:

[0061] Accurately weigh 0.25 g (2.5 mmol) of catechol, dissolve it in 50 mL of deionized water, and oxidize it with 2.5 mmol of sodium periodate. When the solution changes from transparent to red, it indicates that the catechol has been oxidized to an o-benzoquinone intermediate. Then, add 0.188 g (1 mmol) of 2-amino-4-bromophenol to the solution, stir the mixed solution evenly, and place it in an ultrasonic device until it is completely dissolved. Use 1 mol / L sodium carbonate aqueous solution to adjust the pH value of the system to 9, react at 25°C for 45 minutes, and track the progress of the reaction with a dot plate.

[0062] After the reaction is completed, the reaction solution is acidified with hydrochloric acid, the pH value of the system is adjusted to 1, and the reaction solution is placed in a 5°C ice bath for 3 hours to allow the product to be fully precipitated from the aqueous phase; when the reaction solution shows obvious stratification (the aqueous phase is yellow and transparent on the top, and the product layer is brown on the bottom), equal volume extraction is performed with ethyl acetate, and the organic phases are combined and concentrated after repeated three times; after the ethyl acetate is spin-dried using a rotary evaporator, the product pH is washed to neutral with deionized water, and the aqueous solution is removed using a high-speed centrifuge.

[0063] The concentrated product was separated and purified by column chromatography using silica gel powder with a specification of 200-300 meshes, and the eluent was acetone:methanol=1:1 (v / v); the separated components were subjected to low-pressure rotary evaporation and vacuum drying to obtain a phenoxazine dye intermediate, and the final separation yield was 69%;

[0064] The structure of the phenoxazine dye intermediate is as follows:

[0065]

[0066] Example 2

[0067] The phenoxazine dye precursor and the preparation method thereof of the present invention specifically comprise the following steps:

[0068] Weigh 1 mmol (0.293 g) of the phenoxazine dye intermediate of Example 1, dissolve it with 10 mL of acetone and 10 mL of methanol, and pour it into a three-necked flask; weigh 2.5 mmol (0.46 g) of cyanuric chloride, dissolve it with 20 mL of acetone; weigh 2 mmol (0.212 g) of sodium carbonate, dissolve it with 5 mL of deionized water and 15 mL of acetone; pour the cyanuric chloride solution and the sodium carbonate solution into a constant pressure dropping funnel respectively, and connect them to the interface of the three-necked flask; put a rotor into the three-necked flask and place it in a low-temperature constant temperature stirring reaction bath, adjust the pH value of the system to 9, react at 4°C for 26 hours, and track the progress of the reaction with a dot plate.

[0069] After the reaction is completed, the organic solvent is first dried by a rotary evaporator, then washed with deionized water until neutral, centrifuged to separate the deionized water and the product, dissolved and collected with acetone, and the acetone is removed by a rotary evaporator to obtain a solid product; then column chromatography is used for purification, and the eluent is ethyl acetate: acetone = 1:2 (v / v), and the separated components are collected and the solvent is removed by rotary evaporation, and then fully dried in a vacuum oven to obtain a dye precursor, and the final separation yield is 67%;

[0070] The structure of the phenoxazine dye precursor is as follows:

[0071]

[0072] Example 3

[0073] The phenoxazine dye and the preparation method thereof of the present invention specifically comprise the following steps:

[0074] Weigh 1mmol (0.292g) of the phenoxazine dye intermediate of Example 1, dissolve it in 10mL acetone and 10mL methanol solvent, and pour it into a three-necked flask; weigh 2.5mmol (0.46g) of cyanuric chloride and 1mmol (0.106g) of sodium carbonate, pour them into a constant pressure dropping funnel after dissolving, connect them to the interface of the three-necked flask, and slowly drop them in; put a rotor into the three-necked flask and place it in a low-temperature constant temperature stirring reaction bath, adjust the pH value of the system to 9, and react at 4°C for 26h; weigh 1mmol genipin (0.226g) and 1mmol sodium carbonate (0.106g), dissolve them in acetone and deionized water respectively, pour them into a constant pressure dropping funnel, connect them to the interface of the three-necked flask, and slowly drop them in; adjust the pH value of the system to 9, react at 44°C for 10h, and track the progress of the reaction by dot plate.

[0075] After the reaction is completed, the solution after the reaction is firstly removed from the solvents such as acetone and methanol by a rotary evaporator; then washed with deionized water until neutral, separated the unpurified product after the reaction from the deionized water by a centrifuge, dried a small amount of water by a rotary evaporator, and purified by column chromatography, the eluent acetone: methanol = 1: 1 (v / v); the separated components are collected and the solvent is removed by rotary evaporation by a rotary evaporator, and then fully dried in a vacuum oven to obtain a phenoxazine dye, and the final separation yield is 52%;

[0076] The structure of phenoxazine dyes is as follows:

[0077]

[0078] Test Example 1

[0079] The Fourier transform infrared spectra of the phenoxazine dye intermediate of Example 1, the phenoxazine dye precursor of Example 2 and the phenoxazine dye of Example 3 are as follows: Figure 1-Figure 3 shown.

[0080] from Figure 1 It can be seen that at the wave number of 3420cm -1 The stretching vibration peak of -OH is at 3172cm -1 The absorption peak at 1620 cm-1 comes from the stretching vibration of the -N= bond in the phenoxazine heterocycle. -1 The characteristic peak at comes from C=O. Generally, the absorption peak wave number of carbonyl is greater than 1700cm -1 , and the wave number in the figure is 1620cm -1 Because the carbonyl group is connected to the benzene ring, the absorption peak wave number is less than 1700cm due to the conjugation effect. -1 .1063cm -1 The stretching vibration of the COC group is at 580 cm-1.-1 This indicates that the phenoxazine dye intermediate has an active reactive group and a stable conjugated structure and can be used as a raw material for synthesizing other compounds.

[0081] from Figure 2 It can be seen that 3412cm -1 The peak at 3118 cm is generated by the stretching vibration of free -OH. -1 The peak at 3027cm is the vibration peak of the C=N bond on cyanuric chloride. Due to the hydrogen bonding of the nitrogen atom in the cyanuric chloride molecule, -1 The absorption peak of hydrogen bonding of nitrogen atoms in cyanuric chloride molecules is 1605 cm -1 The C=O stretching vibration peak on the phenoxazine ring is at 1055cm -1 The peak at 774 cm is the vibration peak generated by the superposition of the ether vibration peak signals within the phenoxazine heterocycle and the ether bond vibration peak signals between the molecules of phenoxazine and cyanuric chloride. -1 The peak at 537 cm is the stretching vibration peak of the C-Cl bond on the cyanuric chloride ring. -1 The peak at 2 is the stretching vibration peak of the C-Br bond on the phenoxazine ring. This indicates that the phenoxazine dye precursor can be grafted with active groups and used as an active disperse dye. Due to the presence of cyanuric chloride, it can also be used as a single dye.

[0082] from Figure 3 It can be seen that 3445cm -1 The vibration peak at 2954 cm-1 comes from the hydroxyl group on the side chain of genipin. -1 and 2868cm -1 The peak at 1604cm comes from the antisymmetric stretching and symmetric stretching vibrations of -CH3 and -CH2. -1 The peak at 1192cm comes from the stretching vibration of C=O on the phenoxazine ring. -1 The peak at 1081cm comes from the vibration of acetate. -1 and 1104cm -1 The absorption peak at 1044cm comes from the ether bond on the acetate. -1 and 1277cm -1 The vibration peaks at 897cm come from phenoxazine and cyanuric chloride molecules, and cyanuric chloride molecules and ether bonds on genipin groups. -1 The vibration peak of the Genipin ring was found at 770cm -1 The peak at 551 cm comes from the vibration of the C-Cl bond. -1 The peak at comes from the vibration of C-Br. This shows that the phenoxazine dye has dual active groups of cyanuric chloride and genipin, and due to the low polarity characteristics of the parent structure, it can ensure that the dye can be smoothly dissolved in the supercritical CO2 fluid and firmly combined with the fiber.

[0083] Test Example 2

[0084] Acetone was used as the solvent in the concentration range of 5.29×10 -5 mol / L-6.92×10 -5 Under the condition of 1:1 mol / L, the phenoxazine dye intermediate of Example 1, the phenoxazine dye precursor of Example 2, and the phenoxazine dye of Example 3 were tested, and the measured UV-visible absorption spectra were as follows: Figure 4 As shown. Figure 4 It can be seen that the maximum absorption wavelength of the phenoxazine dye intermediate is 444 nm, and the corresponding molar absorption coefficient is 6.576×10 3 L / (mol·cm)- 1 The maximum absorption wavelength of the phenoxazine dye precursor is 400nm, and the corresponding molar absorption coefficient is 5.276×10 3 L / (mol·cm)- 1 The maximum absorption wavelength of the dye is 448nm, and the corresponding molar absorption coefficient is 6.252×10 3 L / (mol·cm)- 1 . The maximum absorption wavelength of the phenoxazine dye precursor is blue-shifted by the action of the cyanuric chloride group; the maximum absorption wavelength of the phenoxazine dye is red-shifted by the action of the genipin group; the maximum absorption wavelengths of the three substances in acetone solvent are inconsistent, but the solutions are all yellow and absorb blue light. This shows that the dye color structure in the phenoxazine dye is less affected by the induction of the active group, which is conducive to obtaining active disperse dyes with different structures but the same color, and further adjusting the dyeing properties of the phenoxazine dye.

[0085] Test Example 3

[0086] Using silk, wool, cashmere, polyester and nylon as dyeing substrates, the phenoxazine dyes of Example 3 were applied to the dyeing process of several dyeing substrates in a supercritical CO2 dyeing equipment (T = 110°C, P = 20MPa, t = 90min).

[0087] The actual effect and color intensity (K / S value) of different dyeing samples are as follows Figure 5-Figure 6 As shown. Figure 5-Figure 6It can be seen that the maximum K / S values ​​of several dyeing samples are all obtained at 435nm, and the dyed fabric has a yellow hue. The color is uniform and the colorability is good. Phenoxazine dyes dye silk, wool, and cashmere fibers by reacting the nitrogen atom on genipin with the amino group. The nitrogen atom enters the genipin ring to form a new conjugated system, and the fiber-dye-color trinity is generated by this nucleophilic substitution reaction to generate a second chromophoric system. Due to the dual effects of the dye matrix and the second chromophoric system, an intramolecular color mixing effect occurs inside fibers such as wool and cashmere, so a small characteristic peak appears at 455nm. Whether it is synthetic fiber or natural fiber, phenoxazine dyes have a good dyeing effect on fabrics in SCF-CO2 fluid.

[0088] Through the soap washing experiment, the color fastness of different dyed samples was tested with reference to the national standard GB / T 3921-2008. The specific test results are shown in Table 1:

[0089] Table 1

[0090]

[0091] As can be seen from Table 1, phenoxazine dyes have achieved relatively ideal color fastness on several dyeing samples. The staining fastness of several samples reached level 4-5 or level 5. The color fastness of wool and cashmere fibers is level 4-5, and the color fastness of silk fabrics is level 4-5, indicating that the combination of amino groups in the fibers and genipin is very good. The dry rubbing fastness and wet rubbing fastness of the five samples are good, all reaching level 4-5 or level 5. Comprehensive analysis shows that phenoxazine dyes can be used for dyeing protein fibers in SCF-CO2, and have good color characteristics and fastness indicators.

[0092] Obviously, the above embodiments are merely examples for clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the protection scope of the invention.

Claims

1. A phenoxazine dye intermediate, characterized in that: The structure of the phenoxazine dye intermediate is shown in Formula III: Wherein, X = Br, Cl, F or NO2; Y=OH, NH2 or NHR, R=CH3 or CH2CH3.

2. A method for preparing a phenoxazine dye intermediate as claimed in claim 1, characterized in that: The following steps are involved: Under the action of an oxidant, the compound of formula I and the compound of formula II react in water to obtain a phenoxazine dye intermediate of formula III; Wherein, the structural formula of Formula I-Formula III is as follows: Wherein, X = Br, Cl, F or NO2; Y=OH, NH2 or NHR, R=CH3 or CH2CH3.

3. The method for preparing a phenoxazine dye intermediate according to claim 2, characterized in that: The molar ratio of the compound of formula I to the compound of formula II is 1:(1-3).

4. The method for preparing a phenoxazine dye intermediate according to claim 2, characterized in that: The oxidant is selected from one or more of sodium periodate, potassium permanganate, potassium persulfate, sodium persulfate and ferric chloride.

5. The method for preparing a phenoxazine dye intermediate according to claim 2, characterized in that: The pH of the reaction is 9-11, the temperature is 20°C-40°C, and the time is 30min-90min.

6. A phenoxazine dye precursor, characterized in that: The structure of the phenoxazine dye precursor is shown in Formula V: Wherein, X = Br, Cl, F or NO2; Y=OH, NH2 or NHR with one H atom removed, R=CH3 or CH2CH3; Z=Cl or F.

7. A method for preparing a phenoxazine dye precursor as claimed in claim 6, characterized in that: The method comprises the following steps: reacting the phenoxazine dye intermediate of formula III according to claim 1 with the compound of formula IV in a solvent to obtain a phenoxazine dye precursor of formula V; Wherein, the structural formula of formula IV-formula V is as follows: Wherein, X = Br, Cl, F or NO2; Y=OH, NH2 or NHR with one H atom removed, R=CH3 or CH2CH3; Z=Cl or F.

8. The method for preparing a phenoxazine dye precursor according to claim 7, characterized in that: The molar ratio of the phenoxazine dye intermediate of formula III to the compound of formula IV is 1:(1-3).

9. A phenoxazine dye, characterized in that: The structure of the phenoxazine dye is shown in Formula VI: Wherein, X = Br, Cl, F or NO2; Y=OH, NH2 or NHR with one H atom removed, R=CH3 or CH2CH3; Z=Cl or F.

10. A method for preparing a phenoxazine dye according to claim 9, characterized in that: The following steps are involved: The phenoxazine dye precursor of formula V described in claim 6 reacts with genipin in a solvent to obtain a phenoxazine dye of formula VI.

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