A method for continuously preparing azo dye in micro-reactors

A micro-reactor, azo dye technology, applied in the direction of azo dyes, monoazo dyes, chemical instruments and methods, etc., can solve the problem that the diazotization reaction temperature is difficult to control, the yield of diazonium salts is not high, and the reaction cycle To avoid decomposition and other side reactions, shorten the residence time, and shorten the reaction period

Active Publication Date: 2017-12-19
深圳智微通科技有限公司
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AI-Extracted Technical Summary

Problems solved by technology

[0006] In order to solve the problems of difficult control of diazotization reaction temperature, low yield of diazonium salt, cumbersome flow process and long reaction cycle in the existing m...
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Abstract

The invention discloses a method for continuously preparing azo dye in micro-reactors in the field of dye synthesis. The azo dye is prepared by firstly subjecting a sodium nitrite solution, an aromatic primary amine and an inorganic acid to a diazotization reaction at room temperature in a first micro-reactor to generate an aromatic primary amine diazonium salt; and then subjecting the aromatic primary amine diazonium salt and a coupling component to a coupling reaction in a second micro-reactor to generate the azo dye. Continuous preparation of the azo dye is achieved by utilizing the micro-reactors, a process is simple, a reaction period is short, and a reaction process can be easily monitored and controlled. Addition of an excessive amount of the sodium nitrite and the coupling agent to increase the reaction speed is not required so that raw materials are saved and the method is environmentally friendly. Reaction liquid in the micro-reactors achieves high-speed collision mixing, a uniform reaction environment is formed immediately, the reaction efficiency is high, and the yield and quality of a reaction product are greatly improved.

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  • A method for continuously preparing azo dye in micro-reactors
  • A method for continuously preparing azo dye in micro-reactors
  • A method for continuously preparing azo dye in micro-reactors

Examples

  • Experimental program(11)

Example Embodiment

[0030] Example 1: The specific steps for the continuous preparation of azo dye product 1# are as follows (such as figure 1 with figure 2 ):
[0031] (1) At room temperature (25°C), take 0.930g of aniline in a 100mL beaker, add 15mL DMF (N,N-dimethylformamide), 2.5mL concentrated hydrochloric acid (37%), 32.5mL deionized water, Stir evenly to obtain material liquid A;
[0032] (2) Take 0.731 g of sodium nitrite solid in a 100 mL beaker, add 15 mL of DMF (N,N-dimethylformamide), 35 mL of deionized water, and stir until the sodium nitrite solid is completely dissolved to obtain feed solution B;
[0033] (3) At room temperature (25°C), take 2.54g of coupling component 1-(4-sulfophenyl)-3-methyl-5-pyrazolone in a beaker, add 60mL water, 30mLDMF( N,N-dimethylformamide), shake it well, add sodium hydroxide solution to adjust the pH of the coupling component to 9.95-10.05, stir until the coupling component is completely dissolved, and prepare liquid C;
[0034] (4) The micro-reactor used in this example is composed of a micro-mixing component and a coil. At room temperature (25°C), the material liquid A and the material liquid B are quickly mixed through the first micro-mixing component to perform the diazotization reaction. The flow pump controls the flow rate of the reaction solution to be 30mL/min, and the length of the coil is used to control the residence time of the reaction to 10s to obtain the diazonium salt solution D;
[0035] (5) The feed liquid C and the diazonium salt solution D are quickly mixed in the second micro-mixing assembly at room temperature (25°C), and a coupling reaction occurs. A constant flow pump is used to control the flow rate of the feed liquid C and the solution D to 60 mL/ min, the length of the coil is used to control the residence time of the reaction to 7s, the inner diameter of the coil used in the reaction is 2mm, and the azo dye aqueous solution is finally obtained.
[0036] Measure the standard working curve of the dye by ultraviolet-visible spectrophotometer, and then calculate the product concentration according to the absorbance of the product at the maximum absorption wavelength, and calculate the azo dye product 1# (see Table 1 for the structural formula), and its yield is 98.73% .

Example Embodiment

[0037] Example 2: The specific steps for the continuous preparation of azo dye product 2-12# are as follows (such as figure 1 with figure 2 ):
[0038] Use p-methoxyaniline, o-chloroaniline, p-nitroaniline, m-nitroaniline, o-nitroaniline, 1-naphthylamine, p-nitrile aniline, N,N-dimethylaniline, p-aminobenzenesulfonic acid , Anthranilic acid, 1-amino-4-naphthalenesulfonic acid instead of the diazonium component aniline in Example 1, and the coupling component 1-(4-sulfophenyl)-3-methyl-5 -Pyrazolinone is used for continuous synthesis of azo dyes, and other conditions are the same as in Example 1, to obtain azo dyes of structure 2-12# (see Table 1 for the structural formula).

Example Embodiment

[0039] Example 3: The specific steps for the continuous preparation of azo dye product 13# are as follows (such as figure 1 with figure 2 ):
[0040] (1) At room temperature (25℃), take 0.930kg of aniline into a 100L container, add 15LDMF (N,N-dimethylformamide), 2.5L concentrated hydrochloric acid (37%), 32.5L deionized water, and stir Evenly, material liquid A is prepared;
[0041] (2) Take 0.731kg of sodium nitrite solid in a 100L container, add 15LDMF (N,N-dimethylformamide), 35L of deionized water, and stir until the sodium nitrite solid is completely dissolved to obtain feed liquid B;
[0042] (3) Take 3.68kg of coupling component H acid monosodium salt at room temperature (25℃), add 60L of water, 30LDMF (N,N-dimethylformamide) and shake well, add sodium hydroxide solution Adjust the pH of the coupling component to 9.95-10.05, and stir until the coupling component is completely dissolved to obtain feed liquid C;
[0043] (4) The micro-reactor used in this example is composed of a micro-mixing component and a coil. At room temperature (25°C), the material liquid A and the material liquid B are quickly mixed through the first micro-mixing component to perform the diazotization reaction. The flow pump controls the flow rate of the reaction solution to be 20mL/min, and the residence time of the reaction is 10s to obtain the diazonium salt solution D;
[0044] (5) The feed liquid C and the diazonium salt solution D are rapidly mixed in the second micro-mixing assembly at room temperature (25°C), and a coupling reaction occurs. A constant flow pump is used to control the flow rate of the feed liquid C and the solution D to 40 mL/ min, using the length of the coil to control the residence time of the reaction to 5s, the inner diameter of the reaction coil used in the reaction is 2mm, and finally the azo dye aqueous solution is obtained.
[0045] The standard working curve of the dye was measured by an ultraviolet-visible spectrophotometer, and then the product concentration was calculated according to the absorbance of the product at the maximum absorption wavelength. The azo dye product 13# was calculated (see Table 1 for the structural formula), and its yield was 98.86% .
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