CN110423492B - Process for the preparation of a leucoindigo salt solution and process for the continuous production of a leucoindigo salt solution - Google Patents
Process for the preparation of a leucoindigo salt solution and process for the continuous production of a leucoindigo salt solution Download PDFInfo
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- CN110423492B CN110423492B CN201910792156.0A CN201910792156A CN110423492B CN 110423492 B CN110423492 B CN 110423492B CN 201910792156 A CN201910792156 A CN 201910792156A CN 110423492 B CN110423492 B CN 110423492B
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09B—ORGANIC DYES OR CLOSELY-RELATED COMPOUNDS FOR PRODUCING DYES, e.g. PIGMENTS; MORDANTS; LAKES
- C09B67/00—Influencing the physical, e.g. the dyeing or printing properties of dyestuffs without chemical reactions, e.g. by treating with solvents grinding or grinding assistants, coating of pigments or dyes; Process features in the making of dyestuff preparations; Dyestuff preparations of a special physical nature, e.g. tablets, films
- C09B67/0071—Process features in the making of dyestuff preparations; Dehydrating agents; Dispersing agents; Dustfree compositions
- C09B67/0077—Preparations with possibly reduced vat, sulfur or indigo dyes
- C09B67/0078—Preparations of vat, sulfur or indigo dyes in liquid form
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09B—ORGANIC DYES OR CLOSELY-RELATED COMPOUNDS FOR PRODUCING DYES, e.g. PIGMENTS; MORDANTS; LAKES
- C09B7/00—Indigoid dyes
- C09B7/02—Bis-indole indigos
Abstract
The invention provides a preparation method of a leucoindigo salt solution and a method for continuously producing the leucoindigo salt solution. The preparation method of the leucoindigo salt solution comprises the following steps: taking a leucoindigo salt solution I with the mass concentration of 30-45% as a substrate material; preparing an indigo suspension solution, wherein the indigo suspension solution comprises 30-55% of indigo and 1.5-3% of a dispersing agent by mass of the total mass of the indigo suspension solution; adding the indigo suspension solution into the substrate material to form a reactant, and introducing hydrogen to perform catalytic hydrogenation reaction in the presence of an alkaline agent and a catalyst to obtain an indigo white salt solution II. The preparation method can realize continuous feeding and continuous production to obtain the leucoindigo salt solution, the obtained leucoindigo salt solution can be stably placed at room temperature, and the leucoindigo salt solution has small fluidity. Further, the leucoindigo salt solution obtained by the preparation method has good fluidity and standing stability.
Description
Technical Field
The invention relates to a preparation method of a leucoindigo salt solution and a method for continuously producing the leucoindigo salt solution, belonging to the field of dye preparation.
Background
Indigo is a widely used vat dye for dyeing cellulosic textile materials, especially cotton warp yarns for blue denim articles. Traditionally indigo is sold in solid form or as an aqueous dispersion of indigo and a dispersant. In order to normally dye cellulose fibers, the cellulose fibers need to be reduced and converted into a water-soluble leuco form, which has substantivity to the cellulose fibers and is oxidized to return to the original indigo structure after dyeing the cellulose fibers, so that the dyeing is completed. In this dyeing process, the metal hydroxide and the excess sodium hydrosulfite are required to be used for effective reduction of indigo, causing a large amount of pollution.
WO-A-94/23114 discloses an ecologically advantageous dyeing process in which an indigo suspension is reduced by catalytic hydrogenation to give an aqueous solution of indigo white salt, and the cellulose fibres are then dyed using conventional methods. The method adopts a catalytic reduction method, replaces the traditional sodium hydrosulfite with hydrogen, can reduce the content of sulfate or organic matters in the wastewater, and reduces the environmental pollution. However, since the viscosity of the indigo suspension is very high, the industrially usable catalytic hydrogenation reduction concentration is generally 20% to 25%, and does not exceed 30%, and the indigo solution exceeding 30% loses its stirring property under heating (the temperature of catalytic hydrogenation is 70 ℃ or higher), and thus the reaction cannot be smoothly performed. Further, when a single alkali metal salt is used as the indigo alkali metal salt obtained by the reduction of indigo, the concentration of the indigo alkali metal salt which is stable in water and does not crystallize is 30% or less. The content of the resulting leucoindigo salt solution is therefore only 20% by weight.
CN1309685A discloses a solution of indigo white salt for dyeing, the concentration can reach 25-55%. This patent uses two alkali metals for the catalytic hydrogenation synthesis of the leucoindigo salt solution, obtaining a mixture of at least two alkali metal hydroxides of neutral leucoindigo salt, wherein none of the alkali metal hydroxides exceeds 70 mol%, in specific example 1 a mixture of 0.8mol potassium hydroxide and 1.2mol sodium hydroxide is used for the catalytic hydrogenation synthesis of leucoindigo, obtaining a leucoindigo salt solution of 45%. However, due to the limitation of reaction concentration, this example uses a two-step hydrogenation reduction method, i.e., a batch hydrogenation operation, in which a 23% indigo salt solution is synthesized in the first step, and then indigo solids are added to the indigo salt solution, and a secondary hydrogenation is performed to obtain a 45% indigo solution. Therefore, the method adopts intermittent hydrogenation operation, and needs to adopt a method of hydrogenation twice, and can complete a cycle reaction by feeding materials twice, the whole reaction is time-consuming, the operation risk is high, and the method belongs to a high-risk operation type.
In addition, example 2 of CN1309685A also mentions that the high-concentration indigo salt solution can be obtained by distillation concentration, but the indigo salt solution is very easy to foam, which results in distillation blanking, so there is no production example for producing the high-concentration indigo salt solution.
GB328104, 1929, a patent of ICI corporation, reports a continuous hydrogenation synthesis process of indigo and alkali mixture, which uses a fixed bed catalytic process, and an aqueous solution mixture of indigo and alkali is passed through a pipeline containing a nickel catalyst to achieve continuous catalytic hydrogenation reduction of indigo at 120-.
Disclosure of Invention
Problems to be solved by the invention
In view of the technical problems in the prior art, the present invention provides a method for preparing a leucoindigo salt solution and a method for continuously producing the leucoindigo salt solution. The preparation method can realize continuous feeding and continuous production to obtain the leucoindigo salt solution, and the obtained leucoindigo salt solution can be stably placed at room temperature.
Further, the method of the invention can reduce the dosage ratio of the alkaline agent in the leucoindigo salt solution so as to reduce the cost.
Means for solving the problems
The invention provides a preparation method of an indigo white salt solution, which comprises the following steps:
taking a leucoindigo salt solution I with the mass concentration of 30-45% as a substrate material;
preparing an indigo suspension solution, wherein the indigo suspension solution comprises 30-55% of indigo and 1.5-3% of a dispersing agent by mass of the total mass of the indigo suspension solution;
adding the indigo suspension solution into the substrate material to form a reactant, and introducing hydrogen to perform catalytic hydrogenation reaction in the presence of an alkaline agent and a catalyst to obtain an indigo white salt solution II.
The method for preparing the indigo white salt solution according to the present invention is characterized in that the molar amount of the alkali agent is 1.5 to 2.5 times the molar amount of the indigo blue.
The preparation method of the indigo white salt solution comprises the steps of preparing an alkali agent, wherein the alkali agent comprises potassium hydroxide and sodium hydroxide, the molar content of the sodium hydroxide is 70-85% and the molar content of the potassium hydroxide is 15-30% based on the total molar content of the alkali agent as 100%.
The preparation method of the indigo white salt solution according to the present invention, wherein the catalyst comprises a heterogeneous catalyst, preferably comprises one or two of Rayney Ni catalyst, Pd/C catalyst.
The method for preparing an indigo white salt solution according to the invention, wherein the indigo blue suspension solution is added to the base material at a rate of 0.1-10%/min of the volume of the base material, preferably at a rate of 0.1-1%/min of the volume of the base material.
The method for preparing the indigo white salt solution according to the present invention, wherein the indigo blue suspension solution is prepared under the condition of less than 50 ℃.
The preparation method of the leucoindigo salt solution according to the invention, wherein the preparation method of the leucoindigo salt solution I comprises the following steps:
step 1) placing a mixture of indigo, an alkaline agent, a dispersing agent, a catalyst and water in a reaction kettle;
step 2) replacing gas in the reaction kettle with hydrogen, and obtaining a reaction product after catalytic hydrogenation reaction;
and 3) adding indigo into the reaction product, replacing gas in the reaction kettle with hydrogen, and performing catalytic hydrogenation reaction again to obtain an indigo white salt solution I.
According to the preparation method of the indigo white salt solution, the reaction pressure of the catalytic hydrogenation reaction is 10-20 bar, preferably 14-17 bar; the reaction temperature is 80-120 ℃, and preferably 90-100 ℃.
The preparation method of the leucoindigo salt solution is characterized in that the mass concentration of the leucoindigo salt solution II is 30-45%.
The invention also provides a method for continuously producing the leucoindigo salt solution, which comprises the preparation method of the leucoindigo salt solution, wherein the leucoindigo suspension solution is continuously fed, the leucoindigo salt solution II is continuously discharged, and the volume in the reaction system is basically kept unchanged.
ADVANTAGEOUS EFFECTS OF INVENTION
The preparation method can realize continuous feeding and continuous production to obtain the leucoindigo salt solution, the obtained leucoindigo salt solution can be stably placed at room temperature, and the leucoindigo salt solution has small fluidity.
Further, the leucoindigo salt solution obtained by the preparation method has good fluidity and standing stability.
In addition, the preparation method has simple technological process operation and is suitable for mass production.
Detailed Description
Various exemplary embodiments, features and aspects of the invention will be described in detail below. The word "exemplary" is used exclusively herein to mean "serving as an example, embodiment, or illustration. Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments.
Furthermore, in the following detailed description, numerous specific details are set forth in order to provide a better understanding of the present invention. It will be understood by those skilled in the art that the present invention may be practiced without some of these specific details. In other instances, methods, means, devices and steps which are well known to those skilled in the art have not been described in detail so as not to obscure the invention.
All units used in the present invention are international standard units unless otherwise stated, and numerical values and numerical ranges appearing in the present invention should be understood to include errors allowed in industrial production.
As used herein, "water" includes any feasible water such as tap water, deionized water, distilled water, double distilled water, purified water, ion-exchanged water, and the like.
If "about", "substantially", "approximately" or the like is used herein, the error may be 5%.
The "room temperature" herein may be 15 to 30 ℃.
First embodiment
A first embodiment of the present invention provides a method for preparing an indigo white salt solution, comprising the steps of:
taking a leucoindigo salt solution I with the mass concentration of 30-45% as a substrate material;
preparing an indigo suspension solution, wherein the indigo suspension solution comprises 30-55% of indigo and 1.5-3% of a dispersing agent by mass of the total mass of the indigo suspension solution;
adding the indigo suspension solution into the substrate material to form a reactant, and introducing hydrogen to perform catalytic hydrogenation reaction in the presence of an alkaline agent and a catalyst to obtain an indigo white salt solution II.
The preparation method can continuously feed and continuously produce the leucoindigo salt solution II, and the obtained leucoindigo salt solution II can be stably placed at room temperature.
< indigo salt solution I >
The leucoindigo salt solution I of the present invention may be commercially available, may be prepared by batch hydrogenation, or may be the leucoindigo salt solution II prepared by the method of the present application. Therefore, the mass concentrations of the leucoindigo salt solution I and the leucoindigo salt solution II of the present invention may be the same or different.
Specifically, the mass concentration of the leucoindigo salt solution I is 30-45%. When the mass concentration of the leucoindigo salt solution I is 30-45%, the production of the leucoindigo salt solution II with high concentration is facilitated. Generally speaking, if 30-45% of the indigo solution II is needed, the mass concentration of the feeding material (the mass concentration of the indigo suspension solution) and the mass concentration of the discharging material (the mass concentration of the indigo salt solution II) are basically consistent, and the indigo with the mass concentration of 30-45% can be continuously obtained.
If the mass concentration of the indigo white salt solution I is less than 30%, even if the mass concentration of the fed indigo blue is 30-45% of the indigo blue suspension solution, the mass concentration of the discharged material can be slowly increased to 30-45% from less than 30% to reach a balance state, so that the product quality is influenced, and the product quality is poor. If the mass concentration of the indigo white salt solution I is more than 45%, the preparation is not easy, the agglomeration is caused, and the fluidity is poor.
Preferably, in the present invention, the mass concentration of the indigo solution I and the mass concentration of the feed (mass concentration of the indigo suspension solution) are kept substantially the same, which is more advantageous for continuously obtaining the indigo solution II with the desired mass concentration. For example: if a 40% strength by mass indigo salt solution I is used and a likewise 40% strength by mass indigo suspension is fed, the strength by mass of the resulting indigo salt solution II is also substantially 40%.
Further, in the first production, the present invention preferably uses, as the leucoindigo salt solution I, a leucoindigo salt solution prepared by a batch hydrogenation operation, from the viewpoint of cost saving. In the non-primary production, the present invention preferably uses, as the leucoindigo salt solution I, the leucoindigo salt solution II obtained in the previous preparation by the preparation method of the present invention, from the viewpoint of energy saving.
When batch hydroprocessing is employed, the process for preparing the leucoindigo salt solution I comprises the steps of:
step 1) placing a mixture of indigo, an alkaline agent, a dispersing agent, a catalyst and water in a reaction kettle;
step 2) replacing gas in the reaction kettle with hydrogen, and obtaining a reaction product after catalytic hydrogenation reaction;
and 3) adding indigo into the reaction product, replacing gas in the reaction kettle with hydrogen, and performing catalytic hydrogenation reaction again to obtain an indigo white salt solution I.
Specifically, in the step 1), the addition amount of the indigo is 20-30% by mass of the total mass of the mixture, for example: 22%, 24%, 26%, 28%, etc.; the addition amount of the alkaline agent is 8-18%, for example: 10%, 12%, 14%, 16%, etc.; the addition amount of the dispersing agent is 0.1-1%, for example: 0.2%, 0.4%, 0.6%, 0.8%, etc.; the addition amount of the catalyst is 1.5-3%, for example: 1.8%, 2.0%, 2.2%, 2.5%, 2.8%, etc. The water is added in an amount of 50-70%, for example: 52%, 55%, 58%, 60%, 65%, 68%, etc.
Further, the specific components of the alkali agent, the catalyst, the dispersing agent, and the like in the preparation of the leucoindigo salt solution I and the reaction conditions of the catalytic hydrogenation are substantially the same as the specific components of the alkali agent, the catalyst, the dispersing agent, and the like in the preparation of the leucoindigo salt solution II and the reaction conditions of the catalytic hydrogenation, and are not described herein again.
In the step 3), 10 to 30% by mass of indigo, for example, 12%, 15%, 18%, 20%, 22%, 25%, 28% by mass of the mixture of the step 1) is added again. Thereby preparing the leucoindigo salt solution I with the mass concentration of 30-45%.
Further, in the present invention, when the leucoindigo salt solution prepared by the batch hydrogenation operation is used as the leucoindigo salt solution I, or the leucoindigo salt solution II prepared previously by the preparation method of the present invention is used as the leucoindigo salt solution I, the catalyst therein may not be removed, and the catalyst may be directly contained in the reactant to simplify the preparation process.
< indigo suspension solution >
In the present invention, in order to obtain the indigo white salt solution II continuously, it is necessary to prepare an indigo blue suspension solution in advance. The indigo suspension solution comprises 30-55% of indigo and 1.5-3% of a dispersing agent by mass of the total mass of the indigo suspension solution. When the content of the indigo in the indigo suspension solution is 30-55% and the content of the diffusant is 1.5-3%, the indigo salt solution II with high concentration and excellent performance can be prepared. Specifically, the indigo suspension solution may have an indigo content of 35%, 40%, 45%, 50%, etc., and a diffusing agent content of 1.8%, 2.0%, 2.2%, 2.5%, 2.8%, etc.
The required indigo suspension can be obtained by adding the dispersing agent without agglomerating the indigo suspension into blocks. Preferably, in the present invention, the diffusing agent may be a diffusing agent NNO, a diffusing agent MF, a diffusing agent CNF, a diffusing agent S, or the like.
Further, in order to prevent the indigo suspension solution from forming a jelly without fluidity, the indigo suspension solution of the present invention is prepared at a temperature of less than 50 ℃, for example, 45 ℃, 40 ℃, 35 ℃, 30 ℃, 25 ℃, 20 ℃, etc.
In addition, the solvent for preparing the indigo suspension solution is not particularly limited in the present invention, and may be a common solvent available in the art. In the present invention, it is preferable to prepare an indigo suspension solution using water as a solvent. The content of water is not particularly limited in the present invention, and the leucoindigo salt solution II required in the present invention can be obtained finally. For example: the addition amount of water may be 42-68.5% by mass of the total mass of the indigo suspension solution.
< alkaline agent >
In the present invention, the alkaline agent is selected from one or more of alkali metal hydroxides, preferably potassium hydroxide and/or sodium hydroxide. More preferably, the present invention uses a combination of potassium hydroxide and sodium hydroxide. By using a combination of potassium hydroxide and sodium hydroxide, the generation of crystals can be reduced, which is advantageous for obtaining the leucoindigo salt solution II excellent in properties.
Further, the inventors of the present invention have found that when the molar content of sodium hydroxide is 70 to 85% and the molar content of potassium hydroxide is 15 to 30% in the alkali agent based on 100% of the total molar content of the alkali agent, the prepared leucoindigo salt solution II has excellent fluidity and storage stability. Preferably, in order to make the effect of the alkali agent more effective, in the present invention, the molar content of sodium hydroxide is more than 70 to 85%, and may be, for example, 72%, 75%, 78%, 80%, 82%, or the like; the molar content of potassium hydroxide is 15 to less than 30%, and may be, for example, 18%, 20%, 22%, 25%, 28%, or the like.
In the present invention, the alkaline agent may be added at the time of preparing the indigo suspension solution, that is, the alkaline agent is added to the indigo suspension solution; when the indigo suspension solution is added to the base material, an alkaline agent may be added to the base material, so that the reactant may contain the alkaline agent.
When the indigo suspension solution is added to the base material, and the alkaline agent is also added to the base material, the alkaline agent may be configured as an alkaline solution, and the alkaline agent may be added to the base material in the form of an alkaline solution. The solvent for preparing the alkali solution is not particularly limited in the present invention, and may be a common solvent available in the art. In the present invention, it is preferable to prepare the alkali solution using water as a solvent. The water content is not particularly limited in the present invention, and the leucoindigo salt solution II required in the present invention can be finally obtained.
Specifically, the indigo suspension solution may be added to the base material at a rate, and the alkali solution may also be added to the base material at a rate. Wherein the addition rate of the alkali solution may be different from the addition rate of the indigo suspension solution.
In the invention, the molar content of the alkaline agent is 1.5-2.5 times of that of the indigo, so that the high-concentration indigo white salt solution II can be effectively prepared.
< catalyst >
The catalyst of the present invention is not particularly limited in kind, and may be a hydrogenation catalyst commonly used in the art. The hydrogenation catalyst generally refers to a catalyst used for addition of a compound to hydrogen, and specifically, the catalyst of the present invention may be a heterogeneous catalyst.
As the heterogeneous catalyst, a catalyst supporting a transition metal element of group VIII, etc. are usually used. The catalyst can be platinum, palladium, nickel carrier catalyst and skeleton nickel. Preferably, the catalyst comprises a heterogeneous catalyst, preferably comprising one or both of a Rayney Ni catalyst, a Pd/C catalyst.
Because the invention is a continuous reaction, the addition of the catalyst is supplemented according to the loss, for example, the Rayney Ni catalyst can be broken and lose the catalytic effect along with the reaction, thereby being discharged out of the reaction system together with the reaction product. In this case, the catalyst may be continuously replenished in order to maintain the reaction rate, and the catalyst may be replenished in an amount corresponding to the amount of the catalyst lost. Therefore, the specific amount of the catalyst used in the present invention is not particularly limited as long as the catalytic hydrogenation reaction can be carried out to produce the leucoindigo salt solution II.
In addition, if the base material leucoindigo salt solution I used in the invention is commercially available, then when the leucoindigo salt solution II is prepared for the first time, a proper amount of catalyst is added according to the need of catalytic hydrogenation reaction.
< catalytic hydrogenation reaction >
In the invention, the indigo suspension solution is added into the substrate material to form a reactant, and the catalytic hydrogenation reaction is carried out by introducing hydrogen under the condition of the existence of an alkaline agent and a catalyst, so as to obtain the indigo white salt solution II.
Preferably, the catalytic hydrogenation reaction can be carried out in a high-pressure reactor. Specifically, the reaction pressure of the catalytic hydrogenation reaction is 10-20 bar, preferably 14-17 bar; the reaction temperature is 80-120 ℃, and preferably 90-100 ℃.
In addition, in the continuous hydrogenation process, the leucoindigo salt solution II is transferred from the reaction system in a continuous filtration mode, and the leucoindigo salt solution II is collected. The reacted indigo white salt solution II can be dissolved in water, while the raw material indigo blue and the catalyst are not dissolved in water and can be remained in the reaction solution for continuous use.
Second embodiment
The second embodiment of the present invention also provides a method for continuously producing an indigo white salt solution, which includes the method for preparing an indigo white salt solution according to the first embodiment of the present invention, wherein the indigo blue suspension solution is continuously fed, the indigo white salt solution II is continuously discharged, and the volume in the reaction system is substantially maintained.
The present invention preferably uses a continuous dosing system when adding the indigo suspension solution to the substrate material to form the reactants, thereby enabling continuous production of the indigo salt solution II.
Specifically, when the indigo suspension solution is prepared to contain the alkaline agent, the indigo suspension solution containing the alkaline agent is added to the base material at a certain rate. In order to maintain the volume of the reaction system not to be changed basically, the discharging rate in the reaction kettle is basically consistent with (basically equal to) the adding rate of the indigo blue suspension solution containing the alkaline agent.
When the indigo suspension solution is prepared without an alkaline agent, the alkaline agent may be dissolved with water to obtain an alkaline solution. Then, while the indigo suspension solution is added to the base material at a certain rate, the alkali solution is also added to the base material at a certain rate. Wherein the addition rate of the alkali solution may be different from the addition rate of the indigo suspension solution.
Generally, the addition rate of the alkaline agent is slower than that of the indigo suspension solution, and the specific rate can be determined based on the concentration of the alkaline solution, generally speaking, the feeding rates of the two liquids are based on the fact that the addition is finished simultaneously within the same time, and in addition, in order to maintain the volume of the reaction system to be basically unchanged, the discharging rate in the reaction kettle is basically consistent with (basically equal to) the sum of the addition rate of the indigo suspension solution and the addition rate of the alkaline solution.
For example, the indigo suspension solution is added to the base material at a rate of 3mL/min, while the alkali solution is added to the base material at a rate of 0.9 mL/min. In addition, in order to maintain the volume of the reaction system unchanged, the discharge rate in the reaction vessel may be 3.9mL/min, i.e., the discharge rate of the leucoindigo salt solution II is 3.9 mL/min.
Preferably, the indigo suspension solution is added to the base stock at a rate of 0.1-10%/min of the volume of the base stock, preferably the indigo suspension solution is added to the base stock at a rate of 0.1-1%/min of the volume of the base stock. The leucoindigo salt solution II is discharged at a rate of 0.1-10%/min of the volume of the base material, preferably the leucoindigo salt solution II is discharged at a rate of 0.1-1%/min of the volume of the base material.
By using the preparation method of the leucoindigo salt solution, the leucoindigo salt solution II can be continuously produced, and the mass concentration of the leucoindigo salt solution II can be 30-45%. In addition, the leucoindigo salt solution II prepared by the invention can be used for preparing dyes.
The preparation method can continuously feed and continuously produce the leucoindigo salt solution II, the obtained leucoindigo salt solution II can be stably placed at room temperature, and the leucoindigo salt solution II has good fluidity. Further, the leucoindigo salt solution II obtained by the preparation method has good fluidity and standing stability.
Examples
Embodiments of the present invention will be described in detail below with reference to examples, but those skilled in the art will appreciate that the following examples are only illustrative of the present invention and should not be construed as limiting the scope of the present invention. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products commercially available.
In an embodiment, the preparation method of the leucoindigo salt solution I comprises the following steps:
adding 250g of indigo blue, 33g of potassium hydroxide, 94g of solid sodium hydroxide, 4g of a diffusant NNO, 600ml of water and 15g of a Rayney Ni catalyst in a water suspension state into a 3L high-pressure reaction kettle with a stirrer, closing the reaction kettle, replacing gas in the reaction kettle with hydrogen, heating to 90 ℃, keeping the pressure at 14 bar, and stirring for reaction for 10 hours under the condition until hydrogen is not absorbed to obtain an indigo white salt solution with the mass concentration of 25.5%.
After the pressure reduction, the hydrogen in the kettle is replaced by nitrogen, the kettle is opened, 238g of indigo powder is added into the indigo white salt solution with the mass concentration of 25.5%, the reaction kettle is closed, after the hydrogen replacement, the temperature is raised to 90 ℃ and 14 bar, and the stirring reaction is continued for about 6 hours until no hydrogen is absorbed. The catalyst-containing leucoindigo salt solution I is obtained, the mass concentration is 40.0%, and the volume is about 1000 ml.
Using this catalyst-containing leucoindigo salt solution I as the base material, it should be noted that, since examples 1 to 4 of the present application were produced continuously, a catalyst-containing leucoindigo salt solution I having a volume of about 1000ml and a mass concentration of about 40.0% was always present in the reaction vessel.
Example 1
The following indigo suspension solutions were prepared: 376g of 30% sodium hydroxide is added into 456.8g of water, 39.6g of potassium hydroxide is added under stirring, 12g of dispersing agent NNO is added after stirring and dissolving, 585.6g of indigo is slowly and slowly added into the solution under the condition of ensuring the temperature of the solution to be 30 ℃, stirring is continued for 30min after adding, and the formation of an indigo suspension solution is ensured, wherein the specific composition and the molar weight of example 1 are shown in the following table 1.
Adding the indigo suspension solution into a continuous metering feeding system, continuously adding the indigo suspension solution into the catalyst-containing indigo white salt solution I at the speed of 4ml/min, maintaining the pressure at 14-15 bar and the temperature at 90 ℃, and simultaneously discharging the indigo suspension solution through filtration at the discharge speed of 4ml/min so as to maintain the volume of the reaction system unchanged. And (3) stopping the reaction until the material addition in the continuous metering feeding system is finished, adding the next batch of material into the feeding system, and continuing the continuous catalytic hydrogenation reaction.
And collecting the materials in the kettle, decompressing, taking out, and measuring the content of the materials to obtain 39.8-40% of indigo white salt solution II, wherein the solution is brown, can be stably placed at room temperature for 1 year, and is free from crystal precipitation.
TABLE 1
Example 2
The following indigo suspension solution 1 was prepared: 9.6g of dispersing agent NNO is added into 540ml of water, 585.6g of indigo is slowly and slowly added into the solution after stirring and dissolving, and stirring is continued for 30min after adding, so as to ensure that an indigo suspension solution is formed.
The following alkali solution 2 was prepared: to 156g of water, 39.6g of potassium hydroxide and 112.8g of sodium hydroxide were slowly added while cooling the solution to prevent overheating, and after dissolution by stirring, the solution was cooled to room temperature, and the specific composition and molar amount of example 2 are shown in Table 2 below.
Adding the indigo suspension solution into a continuous metering feeding system, and continuously adding the indigo suspension solution into the catalyst-containing indigo white salt solution I at the speed of 3ml/min, and maintaining the pressure at 14-15 bar and the temperature at 90 ℃; simultaneously, injecting alkali solution into the reaction kettle through a metering pump at the speed of 0.9 ml/min; meanwhile, the reaction mixture is discharged by filtration at a discharge rate of 3.9ml/min to maintain the volume of the reaction system unchanged. And (3) stopping the reaction until the material addition in the continuous metering feeding system is finished, adding the next batch of material into the feeding system, and continuing the continuous catalytic hydrogenation reaction.
Collecting the materials in the kettle, taking out after pressure relief, measuring the content of the materials, wherein the content of the materials is 40% of indigo white salt solution II, the color of the solution is brown, the solution can be stably placed at room temperature for more than 1 year, and no crystal is separated out.
TABLE 2
| Indigo suspension solution 1 | Weight (g) | Molar content (mol) | Mass percent (%) |
| Indigo blue | 585.6 | 2.235 | 51.6 |
| NNO | 9.6 | / | 0.8 |
| Water (W) | 540 | / | 47.6 |
| Total weight of | 1135.2 | / | 100 |
| Alkali solution 2 | Weight (g) | Number of moles | Mass percent (%) |
| Potassium hydroxide | 39.6 | 0.707 | 12.8 |
| Sodium hydroxide | 112.8 | 2.97 | 36.6 |
| Water (W) | 156 | / | 50.6 |
| Total weight of | 308.4 | / | 100 |
Example 3
The same procedure as in example 1 was followed, but the indigo suspension solution was prepared by changing to: adding 112.8g of flake sodium hydroxide into 456.8g of water, adding 39.6g of potassium hydroxide under stirring, adding 12g of dispersing agent NNO after stirring and dissolving, slowly and slowly adding 585.6g of indigo into the solution under the condition that the temperature of the solution is cooled to be below 50 ℃, and continuously stirring for 30min after adding to ensure that an indigo suspension solution is formed.
The rest of the operations are carried out according to the same method as the example 1, and 39.8 to 40 percent of indigo salt solution II is obtained, the solution color is brown, the solution can be stably placed at room temperature for more than 1 year, and no crystal is separated out.
Example 4
The same procedure as in example 1 was followed, but the following indigo suspension solutions were prepared: adding 329.2g of 30% sodium hydroxide into 483.9g of water, adding 59.3g of potassium hydroxide under stirring, adding 12g of dispersing agent NNO after stirring and dissolving, slowly adding 585.6g of indigo into the solution under the condition of ensuring that the temperature of the solution is lower than 50 ℃, and continuously stirring for 30min after adding to ensure that an indigo suspension solution is formed.
The rest of the operations are carried out according to the same method as the example 1, and 39.8 to 40 percent of indigo salt solution II is obtained, the solution color is brown, the solution can be stably placed at room temperature for more than 1 year, and no crystal is separated out.
Industrial applicability
The present invention makes it possible to produce leucoindigo salt solution in batches by the process of the present invention, and the obtained leucoindigo salt solution can be used as a dye.
The above examples of the present invention are merely examples for clearly illustrating the present invention and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.
Claims (13)
1. A method for preparing a leucoindigo salt solution, comprising the steps of:
taking a leucoindigo salt solution I with the mass concentration of 30-45% as a substrate material;
preparing an indigo suspension solution, wherein the indigo suspension solution comprises 30-55% of indigo and 1.5-3% of a dispersing agent by mass of the total mass of the indigo suspension solution;
adding the indigo suspension solution into the substrate material to form a reactant, and introducing hydrogen to perform catalytic hydrogenation reaction in the presence of an alkaline agent and a catalyst to obtain an indigo white salt solution II.
2. The method for preparing an indigo white salt solution according to claim 1, wherein the molar amount of the alkali agent is 1.5 to 2.5 times the molar amount of the indigo blue.
3. The method for preparing an indigo white salt solution according to claim 2, characterized in that the alkaline agent comprises potassium hydroxide and sodium hydroxide; and based on the total molar content of the alkaline agent as 100%, the molar content of the sodium hydroxide is 70-85%, and the molar content of the potassium hydroxide is 15-30%.
4. The method of preparing an indigo white salt solution according to any of claims 1-3, characterized in that the catalyst comprises a heterogeneous catalyst.
5. The method of preparing an indigo salt solution according to claim 4, characterized in that the catalyst comprises one or both of Rayney Ni catalyst, Pd/C catalyst.
6. The method for preparing the indigo white salt solution according to any one of claims 1 to 3, characterized in that the indigo blue suspension solution is added to the base material at a rate of 0.1 to 10% per minute of the volume of the base material.
7. The method of preparing an indigo salt solution according to claim 6, characterized in that the indigo suspension solution is added to the base mass at a rate of 0.1-1%/min of the volume of the base mass.
8. The method for preparing the indigo white salt solution according to any one of claims 1 to 3, wherein the indigo blue suspension solution is formulated at a temperature of less than 50 ℃.
9. The process for the preparation of the leucoindigo salt solution according to any one of claims 1 to 3, characterized in that the process for the preparation of the leucoindigo salt solution I comprises the following steps:
step 1) placing a mixture of indigo, an alkaline agent, a dispersing agent, a catalyst and water in a reaction kettle;
step 2) replacing gas in the reaction kettle with hydrogen, and obtaining a reaction product after catalytic hydrogenation reaction;
and 3) adding indigo into the reaction product, replacing gas in the reaction kettle with hydrogen, and performing catalytic hydrogenation reaction again to obtain an indigo white salt solution I.
10. The method for preparing an indigo white salt solution according to any of claims 1-3, characterized in that the reaction pressure of the catalytic hydrogenation reaction is 10-20 bar; the reaction temperature is 80-120 ℃.
11. The method for preparing an indigo white salt solution according to claim 10, characterized in that the reaction pressure of the catalytic hydrogenation reaction is 14 to 17 bar; the reaction temperature is 90-100 ℃.
12. The method for preparing the leucoindigo salt solution according to any one of claims 1 to 3, wherein the leucoindigo salt solution II has a mass concentration of 30 to 45%.
13. A process for the continuous production of the leucoindigo salt solution, characterized in that it comprises the process for the preparation of the leucoindigo salt solution according to any one of claims 1 to 12, wherein the indigo suspension solution is continuously fed and the leucoindigo salt solution II is continuously discharged, the volume in the reaction system remaining substantially constant.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB191419848A (en) * | 1913-09-29 | 1915-09-16 | Andre Brochet | Improvements in the Manufacture of Leuco-derivatives of Vat Dye-stuffs. |
| GB328104A (en) * | 1929-04-08 | 1930-04-24 | Ici Ltd | Improvements in the manufacture of leucoindigo |
| CN1120357A (en) * | 1993-03-30 | 1996-04-10 | Basf公司 | Method of dyeing cellulose-containing textile material with hydrogenated indigo |
| CN102516817A (en) * | 2011-12-28 | 2012-06-27 | 河北化工医药职业技术学院 | Method for preparing indigo white solution |
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB191419848A (en) * | 1913-09-29 | 1915-09-16 | Andre Brochet | Improvements in the Manufacture of Leuco-derivatives of Vat Dye-stuffs. |
| GB328104A (en) * | 1929-04-08 | 1930-04-24 | Ici Ltd | Improvements in the manufacture of leucoindigo |
| CN1120357A (en) * | 1993-03-30 | 1996-04-10 | Basf公司 | Method of dyeing cellulose-containing textile material with hydrogenated indigo |
| CN102516817A (en) * | 2011-12-28 | 2012-06-27 | 河北化工医药职业技术学院 | Method for preparing indigo white solution |
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