Synthesis and preparation method of high-concentration KNB slurry

Abstract

The invention discloses a synthesis preparation method of high-concentration KNB slurry, which comprises the following steps: diazotization: preparing initial slurry, dissolving KNB in the initial slurry, then cooling the initial slurry to keep the temperature of the initial slurry below 25 DEG C, adding para-ester to the initial slurry, keeping the temperature of the para-ester below 30 DEG C, and reacting for 2-3 hours to obtain the high-concentration KNB slurry. Stirring, adding a dispersing agent, a catalyst, hydrochloric acid and flake ice, stirring, and adding sodium nitrite to prepare para-ester diazonium salt. According to the scheme disclosed by the invention, the slurry containing KNB is used for replacing water, the temperature of each raw material substance before reaction is reduced, the temperature rise amplitude of the slurry in the reaction process is reduced, the use amount of ice blocks is reduced, the content of solid particles in the finally prepared slurry is increased, and meanwhile, the use amount of a defoaming agent in the reaction process is reduced.

Description

Technical Field

[0001] The invention relates to the field of dye synthesis, and in particular to a method for synthesizing a high-concentration KNB slurry. Background Art

[0002] KNB slurry is a commonly used dye. The current process for synthesizing KNB slurry is to add water, hydrochloric acid, and crushed ice to ethyl sulfate sulfone aniline (referred to as para-ester) to make a uniform slurry, then add sodium nitrite solution for diazotization reaction, and then add solid 1-amino-8-hydroxynaphthalene-3,6-disulfonic acid (referred to as H acid) for a coupling reaction, and finally add defoaming agent and baking soda for a secondary coupling reaction to obtain KNB slurry. The above process has the following defects. The first is that the reaction material is viscous in the later stage of the primary coupling, the reaction time is long, and the temperature will rise during the reaction (especially in summer). Crushed ice must be added continuously to cool it down, which will result in a low solid content; the second is that the secondary coupling in the same reaction pot consumes a large amount of defoaming agent, and a large amount of carbon dioxide is generated in a short time, resulting in a poor working environment. The product quality of this process is poor and the yield is low. Summary of the invention

[0003] In view of the above problems, the present invention proposes a method for synthesizing and preparing a high-concentration KNB slurry.

[0004] The technical solution adopted by the present invention is as follows:

[0005] A method for synthesizing a high-concentration KNB slurry comprises the following steps:

[0006] Diazo step: preparing an initial slurry, wherein KNB is dissolved in the initial slurry, and then cooling the initial slurry to maintain the temperature of the initial slurry below 25° C., adding a para-ester to the initial slurry, wherein the temperature of the para-ester is below 30° C., and then stirring, adding a dispersant, a catalyst, hydrochloric acid and flake ice, stirring, and then adding sodium nitrite to obtain a para-ester diazonium salt;

[0007] A coupling step: step A: H acid slurry dissolution: add the para-ester diazonium salt to part of the initial slurry, the temperature of the initial slurry is lower than 12°C, adjust to pH 2.5, then add H acid, wherein the temperature of the slurry does not exceed 18°C, and stir to react; step B: diazonium salt pH adjustment: add baking soda to the remaining diazonium salt to adjust the pH to 1.5-2.0; C: add the diazonium salt slurry of step B to the H acid slurry of step A (the H acid slurry of step A can also be added to the diazonium salt slurry of step B) to carry out a coupling reaction, and control the reaction temperature at 12-20°C to obtain a coupling slurry;

[0008] Secondary coupling step: sodium bicarbonate is added to the initial slurry, the temperature of the initial slurry is lower than 15°C, and then the primary coupling slurry is added to react, the temperature of the entire reaction solution is maintained at 10°C to 20°C, and the pH of the entire reaction solution is maintained at 5-6.5 to obtain a secondary coupling slurry.

[0009] In this scheme, the selected initial slurry contains a certain amount of KNB, so the solid particle content in the secondary coupling slurry finally prepared can be further improved; at the same time, the temperature of the initial slurry before the reaction is strictly controlled during the reaction process, and the initial temperatures of several raw materials (para-ester and H acid) are strictly controlled, so that the temperature rise of the solution in the entire preparation reaction process is relatively low, thereby reducing the amount of ice added during the preparation process, and finally achieving a relatively high solid content in the prepared slurry. At the same time, in this scheme, after adding H acid, baking soda is added to adjust the pH of the remaining para-ester diazonium salt, and then a coupling is performed, so that the pH of the first coupling reaction is higher than before, the material fluidity is good, the viscosity is low, and the time of the first coupling reaction and the energy consumption during the reaction are reduced. Since the temperature rise of the slurry in the whole reaction process is relatively small, the temperature rise is small and the amount of foam generated is relatively small, so the amount of defoaming agent required to be added is also relatively small.

[0010] In summary, the preparation method controls the use of KNB-containing slurry to replace water, reduces the temperature of each raw material before the reaction, reduces the temperature rise of the slurry during the reaction, reduces the amount of ice used, increases the content of solid particles in the finally prepared slurry, and reduces the amount of defoaming agent used during the reaction.

[0011] Optionally, in the diazo step, the molecular ratio of the para-ester, sodium nitrite and hydrochloric acid is 1:1.0-1.02:1.35-1.8.

[0012] Optionally, in the first coupling step, the molecular ratio of the para-ester diazonium salt to the H acid is 1:0.485-0.5.

[0013] Optionally, after adding sodium nitrite in the diazo step, the pH of the entire reaction solution is maintained at 0.9 to 1.2.

[0014] Optionally, after adding sodium nitrite in the diazo step, the temperature of the entire reaction solution is maintained at 5°C to 12°C.

[0015] Optionally, in the first coupling step, after adding sodium bicarbonate and H acid, the temperature of the reaction solution is maintained at 12°C to 18°C

[0016] Optionally, in the diazo step, after the content of the para-ester in the organic component is less than 0.8%, aminosulfonic acid is added to eliminate excess sodium nitrite.

[0017] Optionally, the mass ratio of the dispersant to the catalyst in the diazo step is 2:1.

[0018] The beneficial effects of the present invention are: using a slurry containing KNB to replace water, reducing the temperature of each raw material before the reaction, reducing the temperature rise of the slurry during the reaction, reducing the amount of ice used, increasing the content of solid particles in the finally prepared slurry, and reducing the amount of defoaming agent used during the reaction. Specific implementation method:

[0019] The present invention is described in detail below in conjunction with embodiments.

[0020] Example 1

[0021] A method for synthesizing high-concentration KNB slurry

[0022] The following steps are included.

[0023] S1, diazo step:

[0024] In this step, the molecular ratio of para-ester: sodium nitrite: hydrochloric acid = 1: 1.0-1.02: 1.35-1.8;

[0025] In a 500ML beaker, add 30 grams of the previous batch of secondary coupling slurry, 10 grams of crushed ice, and then add 28.13 grams of 100% para-ester. After stirring for 30 minutes, add 0.2 grams of dispersant, 0.1 grams of catalyst, and 18 grams of 30% hydrochloric acid. Cool to 10°C, add 30 grams of crushed ice, and then add 23.2 grams of 30% sodium nitrite solution. Control the pH to 0.9-1.2 and the temperature to 5-12°C. React for 1 hour. After detecting that the concentration of the para-ester is less than 0.8%, add 5 grams of crushed ice and 0.1 grams of aminosulfonic acid to eliminate excess sodium nitrite, and finally prepare the para-ester diazonium salt.

[0026] S2, primary coupling step:

[0027] In this step, the molecular ratio of the para-ester diazonium salt: H acid is 1:0.49-0.5

[0028] Add 25 g of the 15°C secondary coupling slurry from the previous batch into a 200 ml beaker, then add 5 g of crushed ice, then add 8 g of para-ester diazonium salt, adjust the pH of the reaction solution to 2.5, add 16.9 g of 100% H acid, and stir for half an hour;

[0029] After adding 1.5 g of baking soda to the remaining diazonium salt, add the above-mentioned H acid slurry, control the temperature at 14-18°C to react for 2 hours and detect the end point. When the reaction ends, add 5-10 g of crushed ice to prepare a primary coupling slurry.

[0030] S3, secondary coupling step:

[0031] In a 500ML beaker, add 10 grams of the previous batch of secondary coupling slurry, 5 grams of crushed ice, and 3 grams of baking soda, then add the primary coupling slurry, add baking soda halfway to control the pH to 5-6.5, and react at 10-20°C to the end point to obtain KNB slurry. The slurry weight is 160-180 grams, with a solid content of 40-50%.

[0032] In this embodiment, the secondary coupling slurry prepared in the previous batch of reactions is reused as the initial slurry, which helps to increase the solid content in the KNB slurry finally prepared.

[0033] Comparison Example

[0034] A preparation method of KNB slurry

[0035] S1 Diazo Reaction Steps:

[0036] Add 40 grams of water to a 500ML beaker, then add 28.13 grams of 100% para-ester, stir for 30 minutes, add 0.2 grams of dispersant, 13.5 grams of 30% hydrochloric acid, add 40 grams of crushed ice, add 23.2 grams of 30% sodium nitrite solution, control the pH to 0.9-1.2, the temperature to 5-12°C, react for 1 hour, detect the purity of the para-ester to be less than 1.0%, then add 10 grams of crushed ice and 0.1 grams of aminosulfonic acid to eliminate excess sodium nitrite.

[0037] S2 primary coupling step:

[0038] Add 16.9 g of 100% H acid to the diazonium salt from which sodium nitrite has been eliminated, control the reaction temperature at 15-18°C, and react for 5-8 hours to detect the end point (add crushed ice during the reaction). Add 5-10 g of crushed ice to the end point of the reaction.

[0039] S3 secondary coupling step:

[0040] Add 5-10 grams of defoamer to the above primary coupling product, then add baking soda to adjust the solution pH to 5.5-6.5 and react to the end point to obtain KNB slurry. Weigh the KNB slurry to 160 grams, with a solid content of 31%.

[0041] The above description is only a preferred embodiment of the present invention, and does not limit the patent protection scope of the present invention. Any equivalent transformations made using the contents of the present invention specification, directly or indirectly used in other related technical fields, are also included in the protection scope of the present invention.

Claims

1. A method for synthesizing a high-concentration KNB slurry, characterized in that: The following steps are included: Diazo step: preparing an initial slurry, wherein KNB is dissolved in the initial slurry, and then cooling the initial slurry to maintain the temperature of the initial slurry below 25° C., adding a para-ester to the initial slurry, wherein the temperature of the para-ester is below 30° C., and then stirring, adding a dispersant, a catalyst, hydrochloric acid and flake ice, stirring, and then adding sodium nitrite to obtain a para-ester diazonium salt; A coupling step: step A, H acid is used for slurrying and dissolving, and the para-ester diazonium salt is added to part of the initial slurry, the temperature of the initial slurry is lower than 12°C, and the pH is adjusted to 2.5, and then H acid is added, wherein the temperature of the H acid does not exceed 18°C, and the reaction is stirred; step B, the pH of the diazonium salt is adjusted, and the remaining diazonium salt is added with baking soda to adjust the pH to 1.5-2.0; C, the diazonium salt slurry of step B is added to the H acid slurry of step A to carry out a coupling reaction, and the reaction temperature is controlled at 12-20°C to obtain a coupling slurry; Secondary coupling step: sodium bicarbonate is added to the initial slurry, the temperature of the initial slurry is lower than 15°C, and then the primary coupling slurry is added to react, the temperature of the entire reaction solution is maintained at 10°C to 20°C, and the pH of the entire reaction solution is maintained at 5-6.5 to obtain a secondary coupling slurry.

2. The method for preparing a high-concentration KNB slurry according to claim 1, characterized in that: The molecular ratio of the para-ester, sodium nitrite and hydrochloric acid in the diazo step is 1:1.0-1.02:1.35-1.

8.

3. The method for preparing a high-concentration KNB slurry according to claim 1, characterized in that: The molecular ratio of the para-ester diazonium salt to the H acid in the first coupling step is 1:0.485-0.

5.

4. The method for preparing a high-concentration KNB slurry according to claim 1, characterized in that: After sodium nitrite is added in the diazo step, the pH of the entire reaction solution is maintained at 0.9-1.

2.

5. The method for preparing a high-concentration KNB slurry according to claim 1, characterized in that: After adding sodium nitrite in the diazo step, the temperature of the entire reaction solution is maintained at 5°C to 12°C.

6. The method for preparing a high-concentration KNB slurry according to claim 1, characterized in that: In the primary coupling step, after adding sodium bicarbonate and H acid, the temperature of the reaction solution is maintained at 12° C. to 18° C.

7. The method for preparing a high-concentration KNB slurry according to claim 1, characterized in that: In the diazo step, when the content of the para-ester in the organic component is less than 0.8%, aminosulfonic acid is added to eliminate the excess sodium nitrite.

8. The method for preparing a high-concentration KNB slurry according to claim 1, characterized in that: The mass ratio of the dispersant to the catalyst in the diazo step is 2:1.