One-pot synthesis of reactive deep black

Abstract

A one-pot synthesis for preparing an aqueous reactive black mixture includes a) dissolving 2-[(4-aminophenyl)sulfonyl]ethanesulfonic acid (vinyl sulphone parabase ester) in water; b) diazotizing the dissolved vinyl sulphone parabase ester using excess nitrous acid or using excess nitrite and an acid, resulting in a diazonium salt and remaining nitrous acid; c) quenching the remaining nitrous acid with sulfamic acid; d) coupling the diazonium salt of step c) with 4-amino-5-hydroxy-2,7-naphthalenedisulfonic acid (H-acid) until the reaction is complete, resulting in Reactive Black 5 (RB 5) and remaining diazonium salt, e) coupling the remaining diazonium salt with 7-acetamido-4-hydroxy-2-naphthalenesulfonic acid (acetyl-J-acid) until the reaction is complete resulting in Reactive Orange 78 (RO 78); and f) obtaining the aqueous reactive black mixture.

Claims

1. A one-pot synthesis for preparing an aqueous reactive black mixture, comprising the following steps a)-f): a) dissolving 2-[(4-aminophenyl)sulfonyl]ethanesulfonic acid (vinyl sulphone parabase ester) in water; b) diazotizing the dissolved vinyl sulphone parabase ester using excess nitrous acid or using excess nitrite and an acid, resulting in a diazonium salt and remaining nitrous acid; c) quenching the remaining nitrous acid with sulfamic acid; d) coupling the diazonium salt of step b) with 4-amino-5-hydroxy-2,7-naphthalenedisulfonic acid (H-acid) until the reaction is complete, resulting in Reactive Black 5 (RB 5) and remaining diazonium salt, e) coupling the remaining diazonium salt with 7-acetamido-4-hydroxy-2-naphthalenesulfonic acid (acetyl-J-acid) until the reaction is complete resulting in Reactive Orange 78 (RO 78); and f) obtaining the aqueous reactive black mixture, wherein steps a) to e) are performed without intermediate purification and at least steps d) and e) are performed under high shear mixing conditions, and wherein the combined concentration of RB 5 and RO 78 at the end of step e) is higher than 0.1 mol/L.

2. The one-pot synthesis according to claim 1, wherein in step b) the molar ratio of vinyl sulphone parabase ester:nitrite is within the range of 1:1.001-1:1.2.

3. The one-pot synthesis according to claim 1, wherein in step c) the molar ratio of remaining nitrous acid:sulfamic acid is within the range of 1:1-1:2.

4. The one-pot synthesis according to claim 1, wherein in step d) the molar ratio of diazonium salt:H-acid is within the range of 2.6:1-2.9:1.

5. The one-pot synthesis according to claim 1, wherein in step e) the molar ratio of remaining diazonium salt:acetyl-J-acid is within the range of 1.0:1-1.2:1.

6. The one-pot synthesis according to claim 1, wherein in the obtained aqueous reactive black mixture the molar ratio of RB 5:RO 78 is within the range of 1.3:1-1.7:1.

7. The one-pot synthesis according to claim 1, wherein the nitrite is sodium nitrite.

8. The one-pot synthesis according to claim 1, wherein the acid is hydrochloric acid.

9. The one-pot synthesis according to claim 1, wherein the pH in step b) is lower than 2.

10. The one-pot synthesis according to claim 1, wherein steps a) to e) are performed in the same reaction vessel.

Description

DESCRIPTION OF EMBODIMENTS

(1) The invention may be illustrated by the following reaction schemes:

(2) ##STR00003## ##STR00004##

(3) A typical one-pot synthesis for preparing an aqueous reactive black mixture according to the present invention comprises the above mentioned steps a)-f). Steps a) to e) are performed without intermediate purification and at least steps d) and e) are performed under high shear mixing conditions.

(4) High shear mixing can be executed in any equipment capable of providing high shear mixing conditions. Such equipment is known in the art and includes, for example, equipment capable of providing a grinding, impact, or similar impingement action, such as horizontal media mills, vertical media mills such as attritors, ball mills, hammer mills, pin disk mills, fluid energy mills, jet mills, fluid jet mills, impingement jet mills, rotor-stators, pelletizers, homogenizers, sonicators, cavitators, and the like. Thus, as used herein for the method of the present invention, high shear mixing means mixing conditions having sufficient energy to produce an intimate mixture of used chemicals and water. The high shear mixers may be either batch, semi-continuous, or continuous mixers. A continuous mixer offers both economic and practical advantages to batch processing equipment and would be generally preferred. Due to the use of high shear mixing conditions, the combined concentration of RB 5 and RO 78 at the end of step e) can be higher than 0.1 mol/L.

(5) Due to the combination of the differentiating features of the current invention, the resulting mixture of RB 5 and RO 78 surprisingly results in a product with an increased purity as compared to prior art RB 5 and RO 78 mixtures.

(6) In a typical reaction, first 2-[(4-aminophenyl)sulfonyl]ethanesulfonic acid (vinyl sulphone parabase ester) is diazotized. Such diazotization reactions are well-known in the art, and can for example be achieved by reacting the vinyl sulphone parabase ester with nitrosyl sulfuric acid or nitrous acid. Usually the nitrous acid is generated in situ from sodium nitrite and a mineral acid. Preferably the reaction is performed with sodium nitrite in an acid solution, preferably hydrochloric acid.

(7) In aqueous solution diazonium salts are unstable at temperatures above 5 C. Therefore, reactions are preferably performed at temperatures between 0 and 5 C. Such reaction temperatures can for example be achieved by performing these reactions in ice/water mixtures. Additionally or alternatively, external cooling can be employed. For example, the reaction can be executed in a reaction vessel which is externally cooled by a cooling bath.

(8) In an embodiment of the current invention vinyl sulphone parabase ester is suspended in water, optionally a mixture of ice and water, and stirred at a temperature between 0 and 5 C. An acid solution, such as 37% HCl is then added. Preferably, the pH of the resulting mixture is at most 2. In order to perform the diazotization, a nitrite salt solution, preferably sodium nitrite in water, is then added. Stirring is preferably continued until complete diazotization has occurred. The temperature is preferably kept below 5 C., i.e. between 0 and 5 C.

(9) Preferably, in step b) the molar ratio of vinyl sulphone parabase ester:nitrite is within the range of 1:1.001-1:1.2. Addition of an excess of nitrite results in complete diazotization of the vinyl sulphone parabase ester, thus no unreacted vinyl sulphone parabase ester will remain. However, too much of an excess of nitrite results in a high amount of nitrous acid remaining after the diazotization. This is disadvantageous, as this remaining nitrous acid can have undesirable effects on the further reaction steps. Therefore, the remaining nitrous acid should be quenched. Higher amounts of remaining nitrous acid result in the need of additional quenching material, which is undesirable from an economic point of view. Furthermore, it leads to an undesirable increased amount of impurities.

(10) Preferably, in the quenching step (step c)), the molar ratio of remaining nitrous acid:sulfamic acid is within the range of 1:1-1:2. The ratio should at least be 1:1 for quenching of all remaining nitrous acid. Higher amounts of sulfamic acid do not provide for a specific benefit in the quenching reaction, but increases the amount and therefore cost of the used sulfamic acid. Furthermore, it results in an extra impurity in the final product. During quenching, the reaction temperature is advantageously kept between 0 and 5 C.

(11) In the target mixture of RB 5 and RO 78, the ratio RB 5:RO 78 is preferably within the range of 1.3:1 to 1.7:1. Such mixtures provide for acceptable black colouring when used as reactive dyes. More preferably, the ratio of RB 5 and RO 78 is in the range of 1.4:1 to 1.6:1. Such ratio's provide for deep black colouring. For an optimal deep black colouring effect, preferably this ratio is in the range of 1.45:1 to 1.50:1.

(12) H-acid can be added, for example as an aqueous suspension, immediately after quenching the remaining nitrous acid with sulfamic acid. Preferably the reaction temperature is between 0 and 5 C. Related to the above mentioned ratios of RB 5:RO 78, in step d) the molar ratio of diazonium salt:H-acid is preferably within the range of 2.6:1 to 2.8:1. This will result in a ratio of RB 5:remaining diazonium salt of 1.7:1 to 1.3:1. More preferably, the molar ratio of diazonium salt:H-acid is within the range of 2.6:1 to 2.7:1.

(13) After all H-acid has been consumed, the reaction can be continued by adding acetyl-J-acid to the reaction mixture (step e). Acetyl-J-acid can be added in the form of an aqueous slurry. As acetyl-J-acid is a valuable resource which is less easy to prepare than the diazonium salt, the diazonium salt is preferably present in at least equimolar amounts at the beginning of step e). In this way all acetyl-J-acid can react to form RO 78. More preferably, the remaining diazonium salt is present as an excess, to ensure that all acetyl-J-acid will react to form RO 78. Most preferably, in step e) the molar ratio of remaining diazonium salt:acetyl-J-acid is within the range of 1.0:1-1.2:1. Lower relative amounts of diazonium salt lead to an undesirable excess of acetyl-J-acid, whereas higher relative amounts of diazonium salt result in a too high surplus of diazonium salt. This needs to be removed from the resulting dye mixture and results in unnecessary costs and/or purification steps. The pH of the reaction of step e) is preferably adjusted to pH 5, for example through the addition of a sodium carbonate solution. Optionally, the pH is checked during the reaction, and re-adjusted if necessary.

(14) Preferably, steps a) to e) are performed in the same reaction vessel as this enables to make full advantage of the one-pot process properties of the current invention.

(15) The current invention further provides for the use of an aqueous reactive black mixture prepared according to the above mentioned process in textile dying, i.e. a process of adding color to textile products.

(16) Preferably, the dye mixtures according to the invention are used in printing of textiles.

(17) More preferably, the dye mixtures according to the invention are used in inkjet printing of textiles.

Example

(18) To prepare a target Mixture of 0.1475 mole of Black 5 and 0.1 mole of Orange 78, vinyl sulphone parabase ester (115.5 g) was suspended in ice/water (1 l) and stirred at 0-5 C. whilst 37% HCl (80.2 g, 68 ml, 0.814 mole) was added. To this was then added a solution of sodium nitrite (28.0 g, 0.406 mole) in water (100 ml) over 15 min's at the same temperature, maintained through external cooling. The mixture was stirred for 1 h at 0-5 C. and then analyzed by HPLC, which showed no starting material remained, indicating complete diazotization had occurred.

(19) Excess nitrous acid was quenched by the addition of sulfamic acid (1 g). H-Acid (59.1 g, 0.1475 mole) was suspended well in water (100 ml) and the suspension added to the above diazotization reaction. After 3 h stirring using a Silverson L5M-A high shear mixer at 0-5 C., paper run-out with diazo-PNA stain, indicated that all H-acid had been consumed.

(20) The acetyl-J-acid slurry prepared in Step 1 (135 g, 0.1 mole) was adjusted to pH 5 with 2N HCl and then added to the reaction. Over 30 minutes, the reaction was adjusted to pH 5 through the addition of 2M sodium carbonate solution (180 ml required). The reaction was then stirred overnight using a Silverson L5M-A high shear mixer at pH 5.0 allowing it to warm up to room temp. No further alkali or acid solution was required to maintain pH 5 overnight. The total reaction volume was about 2 liter. Table 1 gives an overview of the reactants that were used.

(21) TABLE-US-00001 TABLE 1 Reactants Mol. Weight Mass Materials (g/mol) (g) Moles Vinyl sulphone 286.5 115.5 0.403 parabase ester H-Acid 401 59.1 0.1475 Sodium nitrite 69 28.0 0.406 N-Acetyl-J-acid 1365 136.5 0.1 37% HCl 98.6 80.2 0.814 2M Na.sub.2CO.sub.3 solution 180 ml 0.36 Sulfamic acid 97.1 1 0.01

(22) For convenience, the total reaction liquor was freeze dried to give a black solid which was slurried in acetone to homogenise and to render it more handleable, meaning less static, less dusty, and having less volume. The solid was filtered off and dried at 40 C. under vacuum overnight.

(23) The dye content was analyzed by nitrogen content obtained from micro analysis. As the dye sample will contain extra carbon from residual acetate and sodium carbonate, the % dye content is calculated from the nitrogen content, obtained by micro analysis. Mw.sub.Black5=903.89 g/mol; m.sub.Black5=0.1475 mol903.89 g/mol=133.3 g Mw.sub.Orange78=573.57 g/mol; m.sub.Orange78=0.1 mol573.57 g/mol=57.4 g Both dyes: 133.3 g+57.4 g=190.7 g dye mixture expected Expected nitrogen content: (0.1475 mol5 N-atoms in Black 5+0.1 mol3 N-atoms in Orange 78)14.007190.7=7.62% Found nitrogen content: 4.90% Dye content=4.90%7.62%=64.3%

(24) Thus, the total mass of freeze dried solid was 283.2 g at 64.3% strength which corresponds to 182.1 g at 100% strength. The solid dye mixture was analyzed using UV-Vis as an aqueous solution of 10 ppm (see FIG. 1: UV-Vis spectrum of the resulting product) and HPLC (see Tables 2 and 3).

(25) In FIG. 1:

(26) =601 nm: A/g=23.2 at 64.3% strength corresponding to A/g=36.1 at 100% strength

(27) =480 nm: A/g=17.1 at 64.3% strength, corresponding to A/g=26.6 at 100% strength

(28) =392 nm: A/g=12.0 at 64.3% strength, corresponding to A/g=18.6 at 100% strength

(29) Analytical HPLC measurements were performed on a Waters Acquity UPLC equipped with PDA and MS detectors. The used column was a Waters Acquity Phenyl BEH column (1.7 m, 2.1150 mm). The column was maintained at 20 C. Eluent A consisted of 5% formic acid buffer (pH 3) in acetonitrile, and eluent B consisted of 5% formic acid buffer (pH 3) in water. The injection volume was 10 microliter, and the flow rate was 0.5 mL/min. The analysed samples were dissolved in water and diluted in water to a concentration of 100 ppm. The used gradient is summarized in Table 2.

(30) TABLE-US-00002 TABLE 2 HPLC gradient Time (min.) Eluent A (%) Eluent B (%) 0 20 80 1 20 80 8 80 20 10 80 20 12 20 80 14 20 80

(31) TABLE-US-00003 TABLE 3 HPLC analysis of dye mixture prepared according to example 1 ( = 478 nm) RT Area Height % Area 1 6.911 3626 588 0.17 2 7.173 945 375 0.04 3 7.758 624337 45188 29.38 4 8.702 1173514 342091 55.22 5 8.874 28186 9640 1.33 6 8.927 25138 6271 1.18 7 9.025 21796 5712 1.03 8 9.143 5584 1219 0.26 9 9.255 61731 20960 2.90 10 9.411 1649 430 0.08 11 9.771 12439 2689 0.59 12 9.957 11842 4617 0.56 13 10.391 84935 26625 4.00 14 10.665 35814 6574 1.69 15 10.982 2979 521 0.14 16 11.198 948 486 0.04 17 11.447 1118 439 0.05 18 11.875 1670 421 0.08 19 12.036 825 275 0.04 20 12.156 18845 6348 0.89 21 12.651 968 349 0.05 22 12.723 2429 784 0.11 23 13.841 555 240 0.03 24 13.964 1319 399 0.06 25 14.195 1998 565 0.09 25 14.195 1998 565 0.09

Comparative Example

(32) In a comparative experiment, a mixture of RB 5 and RO 78 was prepared by mixing commercially available RB 5 and commercially available RO 78 in a ratio of RB 5:RO 78 of 1.48:1. HPLC analysis was performed using an identical analysis method as described for the above example (see Table 4).

(33) TABLE-US-00004 TABLE 4 HPLC analysis of dye mixture of individually prepared RB 5 and RO 78 ( = 478 nm) RT Area Height % Area 1 6.865 4379 599 0.14 2 7.490 565 290 0.02 3 7.719 749685 59371 24.76 4 8.622 9512 2765 0.31 5 8.685 1559417 408577 51.50 6 8.942 34752 4912 1.15 7 9.223 4803 1236 0.16 8 9.285 3416 1429 0.11 9 9.337 10174 3427 0.34 10 9.804 2903 1308 0.10 11 9.824 4894 1506 0.16 12 9.952 18627 6986 0.62 13 10.379 105732 32911 3.49 14 10.645 54802 9306 1.81 15 10.915 3710 1267 0.12 16 11.041 3615 1266 0.12 17 11.079 868 349 0.03 18 11.195 719 304 0.02 19 11.757 833 324 0.03 20 12.018 7995 2589 0.26 21 12.128 431446 143164 14.25 22 12.509 591 248 0.02 23 12.674 2477 787 0.08 24 13.098 766 392 0.03 25 13.536 853 258 0.03 26 13.827 8351 2806 0.28 27 13.960 2040 492 0.07

(34) A comparison of the analyses of the example according to the present invention and the comparative example reveals that the dye mixture as prepared according to the present invention comprises less impurities. The most predominant difference is the vast reduction in the impurity eluting at around 12.13 min. It is believed that this impurity is mono-hydrolysed RB 5:

(35) ##STR00005##

(36) The one-pot synthesis according to the present invention surprisingly leads to a vast reduction of the above mentioned impurity.

(37) TABLE-US-00005 TABLE 3 Comparison of HPLC Analyses of mixtures of RB 5 and RO 78 ( = 478 nm) Presence in dye mixture Presence in dye mix- RT of individually prepared ture prepared according (min.) RB 5 and RO 78 (%) to example (%) Component 7.7 24.76 29.38 RB 5 8.7 51.50 55.22 RO 78 12.13 14.25 0.89 Impurity