Background
The silk fiber has the problem of poor color fastness, and the existing dyeing methods suitable for the silk fiber have defects. The synthetic dyes currently used for silk dyeing mainly include acid dyes, metal complex dyes and reactive dyes. Although the acid dye has bright color, complete chromatogram and high dye uptake, the acid dye is combined with silk fiber through ionic bond force, is easily influenced by solvation of water, and generally has poor fastness to wet treatment. The metal complex dye forms a complex on the fiber under the action of metal (chromium and cobalt) ions, has good wet-resistant treatment fastness, but the fiber and a large amount of metal ions in the dye liquor can cause negative effects on human health and environment. The reactive dye structure is provided with reactive groups, and can react with amino at the chain end of a silk fiber macromolecule and phenolic hydroxyl in a tyrosine residue to generate covalent bonds to dye the fibers during dyeing, however, the covalent bonds formed between the reactive dye and protein fibers are mostly ester groups and amide groups, and the covalent bonds are easily hydrolyzed and broken in stronger acid and alkali media, so that the reactive dye cannot completely solve the problem of the moisture-proof treatment fastness of the silk fibers. In addition, the reactive dye has serious hydrolysis problem in the high-temperature color fixing process, generates a large amount of colored wastewater, and has high sewage treatment difficulty. Therefore, designing a dye which can form firm covalent bond combination with silk fiber, has excellent fastness to wet treatment and reduces the discharge capacity is a problem to be solved urgently in the dyeing and finishing industry.
Silk fiber dyeing usually adopts water as a medium, dye molecules enter an amorphous area of the fiber to form a physical or chemical combination process with amino acid, and the dyeing performance of the silk fiber is closely related to the morphological structure, the aggregation structure and the amino acid composition of the fiber. The silk is composed of silk fibroin and sericin, and silk fibroin fibers after degumming of the silk have high crystallinity, few amino dye mats and poor deep dyeing property. The amino acid of silk fiber contains phenol structure, which is distributed in amorphous area of fiber easy to permeate water solution, and is suitable for reactive dyeing mat.
Chemical modification of protein side groups is an important method for improving the chemical properties of proteins. Tyrosine residue in protein or polypeptide can react with aldehyde substance, primary aromatic amine and derivatives thereof in three components under mild conditions, so that the three substances are firmly combined through covalent bonds, and the reaction is called Mannich reaction.
The inventor's task group has filed for ' a covalent bond coloring method for silk ' (2013107373959), which is a method (abbreviated as normal temperature Mannich dyeing method) for firmly connecting dye molecules to silk macromolecules by using a Mannich reaction of an aromatic primary amine dye and tyrosine residues in silk fibers under the action of aldehydes, and has mild dyeing conditions (30 ℃, pH4, 10h of dyeing holding time) and excellent fastness to wet treatment. Namely, the acid dye containing monoaryl primary amine group is combined with a tyrosine residue covalent bond in silk fiber by utilizing aldehyde substance bridging through Mannich reaction, so that the moisture-proof treatment fastness of silk is improved.
However, the dye involved in the patent only contains one primary arylamine group, the reaction efficiency on silk is not high, more dye can not be reacted and fixed with fiber, colored wastewater with higher concentration is generated, and the sewage treatment cost is higher.
Disclosure of Invention
The invention aims to provide a bi-aromatic primary amine acid dye containing an H acid structure and a preparation method thereof. Aiming at the problem of low reaction rate of the monoaromatic primary amine dye, two aromatic primary amine groups are simultaneously introduced into a dye structure containing an H acid structure, and the color fixing efficiency of the double aromatic primary amine dye containing the H acid structure is improved by utilizing the Mannich reaction principle.
In order to solve the technical problems, the invention provides a bi-aromatic primary amine acid dye containing an H acid structure, which has a structural general formula as follows:
in the formula: r1Is NH2、H;R2Is NH2、H、Cl、CH3;R3H, Cl, Br; and R is1、R2In which only one amino group is present (i.e., R)1、R2Not all being NH2) (ii) a When R1 is NH2When R is2And R3Not both can be H.
As the improvement of the bi-aromatic primary amine acid dye containing the H acid structure, the structural formula is any one of the following:
the invention also provides a preparation method of the bi-aromatic primary amine acid dye containing the H acid structure, which is suitable for reactive dyeing of silk, and the preparation method comprises the following steps:
1) and diazotization reaction:
in hydrochloric acid aqueous solution, carrying out diazotization reaction on nitroaniline compounds and sodium nitrite to prepare a diazo component serving as an intermediate product;
2) and (3) coupling reaction:
carrying out coupling reaction on the diazo component to obtain a coupling product;
3) and nitro reduction:
and carrying out nitro reduction reaction on the coupling product to prepare the target product, namely the bi-aromatic primary amine acid dye containing the H acid structure.
The improvement of the preparation method of the bi-aromatic primary amine acid dye containing the H acid structure of the invention is as follows: the nitroaniline compounds are 2-chloro-4-nitroaniline, 3-methyl-4-nitroaniline and 2-chloro-5-nitroaniline.
The bi-aromatic primary amine acid dye containing the H acid structure has the following technical advantages:
compared with the existing commercialized acid dye containing an H acid structure, the dye disclosed by the invention can be subjected to a Mannich reaction to enable the dye and fibers to be combined through a covalent bond, so that the reaction efficiency is improved (the reaction time is only 5 hours), and the fixation rate can reach more than 97%, and is remarkably superior to that of a red dye (C.I. acid red 33) in patent No. 2013107373959 under the same dyeing condition.
In conclusion, the invention introduces two primary amine groups with excellent nucleophilic ability into the azo-type acid dye containing the H acid structure, develops the bi-aromatic primary amine acid dye which is suitable for Mannich reactive dyeing of silk and has excellent performance, and has good application prospect.
Detailed Description
The invention will be further described with reference to specific examples, but the scope of the invention is not limited thereto:
the hydrochloric acid in the invention is 36 to 38 percent of concentrated hydrochloric acid.
Example 1, a method for preparing a bis-aromatic primary amine acid dye containing an H acid structure, sequentially comprising the following steps:
1) and diazotization reaction:
1.72g (0.01mol) of 2-chloro-4-nitroaniline was added to a 250mL three-necked flask, and 10mL of hydrochloric acid and 30mL of water were added to the three-necked flask with stirring, and the temperature was controlled at 0 to 5 ℃ and the mixture was stirred for about 15min until the solid (i.e., 2-chloro-4-nitroaniline) was completely dissolved. Weighing 0.828g (0.012mol) of sodium nitrite, dissolving in 5mL of water, quickly adding into the three-neck flask, reacting at 0-5 ℃ for 30min, after the reaction is finished (namely, after the set reaction time is up), adding urea to remove redundant sodium nitrite (KI test paper is used for detecting whether the urea is added to an excessive amount and the test paper is not changed in color within 1-2 s), and placing the obtained product as a diazo component in an ice bath for later use.
2) And (3) coupling reaction:
weighing 3.41g (0.01mol) of H acid monosodium salt, placing the H acid monosodium salt in a beaker, adding about 100mL of NaOH solution with the mass concentration of 1% to completely dissolve the H acid monosodium salt, adjusting the pH value to 9-10 by using NaOH or sodium bicarbonate, transferring the H acid monosodium salt to a 500mL three-neck flask, adding excessive sodium carbonate to precipitate under the condition of mechanical stirring, controlling the reaction temperature to be 0-5 ℃, and dropwise adding the diazo component obtained in the step 1) into the three-neck flask (the dropwise adding time is about 1 hour); after the dropwise addition, the pH value of the reaction is adjusted to 9-10 by using sodium carbonate, and the reaction is carried out for 2 hours under the condition of heat preservation (0-5 ℃).
After the reaction is finished, adding sodium chloride solid into the obtained reaction product solution until sodium chloride is saturated, salting out a dye product, and filtering to obtain a salt-containing dye (salt-containing product).
Removing salt in the salt-containing dye by adopting a DMF-ether method, collecting and drying, and specifically comprising the following steps: DMF-Ether method: dissolving 10g of salt-containing dye in 75mL of DMF (dye dissolved and salt insoluble), filtering to remove salt, adding 500mL of anhydrous ether into the filtrate to separate out the dye, filtering, collecting a filter cake, and drying at room temperature to constant weight; obtaining a coupling product (pure product);
3) reduction of nitro group
A100 mL three-necked flask was charged with 30mL of H2O, 5.45g (0.01mol) of the coupling product obtained in step 2) above, thermostatted to 75 ℃. Weighing Na2S·9H2O(4.80g),NaHCO3(1.68g) dissolved in H2O (25ml), the solution was slowly added dropwise to the flask over about 1h, and after the dropwise addition was completed, the reaction was kept at room temperature (75 ℃) for 4h, followed by cooling to room temperature.
After the reaction is finished, adding sodium chloride solid into the obtained reaction product solution until sodium chloride is saturated, salting out a dye product, and filtering to obtain a salt-containing dye (salt-containing product).
Removing salt in the salt-containing dye by adopting a DMF-ether method, collecting and drying, and specifically comprising the following steps: DMF-Ether method: dissolving 6g of salt-containing dye in 45mL of DMF (dye dissolved and salt insoluble), filtering to remove salt, adding 300mL of anhydrous ether into the filtrate to separate out the dye, filtering, collecting a filter cake, and drying at room temperature to constant weight; obtaining the diarylide primary amine acid dye AD-1 containing H acid structure.
The structural formula of the dye AD-1 is as follows:
1H NMR(400MHz,DMSO-d6):δ8.11(s,1H),7.84(s,1H),7.61(d,1H),7.30(s,1H),6.67(s,1H),6.54(d,1H);ESI MS(m/z,%):493.0([M-Na]-,100)。
example 2, a method for preparing a bis-aromatic primary amine acid dye containing an H acid structure:
0.01mol of 2-chloro-4-nitroaniline from example 1, step 1) was changed to 0.01mol of 3-methyl-4-nitroaniline;
the rest is equivalent to the embodiment 1; obtaining the diarylide primary amine acid dye AD-2 containing H acid structure.
The structural formula of the dye AD-2 is as follows:
1H NMR(400MHz,DMSO-d6):δ8.12(s,1H),7.84(s,1H),7.49(m,2H),7.26(s,1H),6.55(d,1H),2.35(s,3H);ESI MS(m/z,%):473.0([M-Na]-,100)。
example 3, a method for preparing a bis-aromatic primary amine acid dye containing an H acid structure:
0.01mol of 2-chloro-4-nitroaniline from example 1, step 1) was changed to 0.01mol of 2-chloro-5-nitroaniline;
the rest is equivalent to the embodiment 1; obtaining the diarylide primary amine acid dye AD-3 containing H acid structure.
The structural formula of the dye AD-3 is as follows:
1H NMR(400MHz,DMSO-d6):δ8.15(s,1H),7.83(s,1H),7.25(m,2H),7.08(s,1H),6.60(d,1H);ESI MS(m/z,%):493.0([M-Na]-,100)。
the application of the bi-aromatic primary amine acid dye containing the H acid structure in the Mannich dyeing of silk fabrics is illustrated by experiments.
Experiment 1, 1g of silk fabric is taken, materials are fed according to the molar ratio of 2% o.w.f of dye to formaldehyde to dye of 30:1, the dyeing bath ratio is 1:50, the pH value is adjusted to 4.0-4.5 by using acetic acid-sodium acetate buffer solution, the dyeing temperature is 30 ℃, and the heat preservation time is 5 hours.
And (3) after dyeing is finished, taking out the dyed cloth sample, washing (the water amount for washing is 200mL), combining the dyeing residual liquid and the washing liquid, carrying out constant volume measurement on absorbance, and solving the dye uptake of the dye by utilizing the Lambert-beer law. The color fixing rate is calculated according to the K/S value of the color depth of the cloth before and after stripping, and the main method is as follows: the dyed silk fabric was immersed in 300mL DMF and extracted at 95 ℃ for 30 min. The fabric was then removed, washed with water and dried at room temperature. Calculating the fixation rate of the primary arylamine dye on the silk by using a formula (1):
in equation (1)% F is calculated based on the K/S value measured at the maximum absorption wavelength of the dye on the silk fabric. (K/S)0And (K/S)1The K/S values are respectively measured at the maximum absorption wavelength of the dye on the silk fabric before and after DMF stripping. And the soaping color fastness resistance and wet rubbing fastness of the dyed cloth sample are respectively measured according to ISO 105-X12:2001 and ISO 105-F06: 2000. The results are shown in Table 1.
TABLE 1 dyeing performance and fastness data of acid dyes on silk fabrics
|
Dye uptake (%)
|
Fixation ratio (%)
|
Fastness to soaping (grade)
|
Fastness to wet rubbing (grade)
|
Example 1(AD-1)
|
98.7
|
95.6
|
4-5
|
4-5
|
Example 2(AD-2)
|
97.8
|
96.1
|
4-5
|
4-5
|
Example 3(AD-3)
|
98.8
|
96.4
|
4-5
|
4-5
|
C.i. acid red 33
|
96.3
|
48.5
|
4-5
|
4
|
C.I. acid Violet 7
|
84.3
|
0
|
2-3
|
3
|
AD-5
|
95.7
|
82.4
|
4-5
|
4 |
Comparative example 1, the dye in experiment 1 was changed to the following commercial dye containing H acid structure: c.i. acid red 33, c.i. acid violet 7; the rest is identical to experiment 1. The results obtained are shown in Table 1.
From table 1, it can be seen that: the dye uptake and the fixation rate of the diarylide primary amine dyes AD-1, AD-2 and AD-3 of the invention are all over 97 percent, the dye utilization rate in the dye process is extremely high, and the fastness to color change caused by soaping and the fastness to wet rubbing both reach 4-5 grades, which shows that the dyes and silk fibers are efficiently fixed together through Mannich reaction. The commercial acid dye C.I. acid violet 7 does not contain aromatic primary amine groups in the structure, can not perform Mannich reaction with silk, has poor soaping color change resistance fastness and wet rubbing fastness, is 2-3 grade or 3 grade, has the dye uptake lower than 90 percent and has the color fixing rate of 0. The commercial acid dye C.I. acid red 33 containing the monoaromatic primary amine group in the structure can perform Mannich reaction dyeing with silk to obtain better dye-uptake and color fastness, but the color fixation rate is lower than 50%, which indicates that a large amount of dye cannot form good reactive fixation with silk fiber, and the dyeing performance of the dye is obviously lower than that of the diarylamine primary amine dyes AD-1, AD-2 and AD-3.
In summary, in the azo-type acid dye containing the H acid structure, because two active groups exist in the structure, the dye uptake and the fixation rate of the dye are both obviously improved, and the soaping color change resistance fastness and the wet rubbing fastness of the dye are also obviously improved. Above-mentioned advantage can improve the dyeing efficiency of dyestuff to silk fibre, reduces dyestuff content in the waste water, satisfies the industrial production demand.
Comparative example 2, the acid dye in experiment 1 was changed to the dye AD-4 as follows, and the remainder was identical to experiment 1.
The dye AD-4, because the amino is in the ortho position of the azo group, the silk dyed by Mannich does not obtain the required color, mainly because the azo bond of the amino and the ortho position and formaldehyde are decomposed through the Mannich reaction in three components, the azo bond is destroyed, the color fades, and the reactive dyeing of the silk cannot be realized. Therefore, the amino position has great influence on the dyeing performance, and the color fixing effect and the reaction efficiency cannot be improved by simply introducing the amino into the color body.
Comparative example 3, the acid dye in experiment 1 was changed to the dye AD-5 described below, and the remainder was identical to experiment 1. The results obtained are shown in Table 1.
According to the dye AD-5, amino on a benzene ring is positioned at a para position of an azo group and is influenced by an electron withdrawing effect of an azo bond, the electron cloud density on an amino nitrogen atom is reduced, the Mannich reactivity is influenced, the fixation rate is 82.4% after dyeing according to the method of the experiment 1 and is lower than that of the optimized diarylamine dyes AD-1, AD-2 and AD-3, and the introduction of the amino position and other substituents can influence the Mannich reaction performance of the dye, so that the efficient reactive dyeing can not be simply realized through molecular design.
Finally, it is also noted that the above-mentioned lists merely illustrate a few specific embodiments of the invention. It is obvious that the invention is not limited to the above embodiments, but that many variations are possible. All modifications which can be derived or suggested by a person skilled in the art from the disclosure of the present invention are to be considered within the scope of the invention.