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Method for synthetizing DSD acid (4,4'-diamino-2,2'-stilbenedisulfonic acid) oxidation intermediate by water phase pressurization method

A technology for acid oxidation and intermediates, which is applied in the field of synthesizing DSD acid oxidation intermediates by the water phase pressurization method, can solve the problems of easy generation of by-products, reduce the possibility of by-products, and achieve high product yield and good quality Effect

Inactive Publication Date: 2017-12-01
连云港莱亚化学有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although this method has the advantages of using water as a solvent, mild conditions, and high selectivity, due to the formation of DNS in the early stage of production, some of the DNS double bonds are easily broken and by-products are generated during the continuous heating and oxygen supply period.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] Example 1, a method for synthesizing DSD acid oxidation intermediates by water phase pressurization method, comprising the following steps: (1) adding the raw material nitrotoluene o-sulfonate and the catalyst into the reaction vessel according to the mass ratio of 1:0.001-0.01 , and add water 5-6 times the weight of the raw material, then add alkali to make the alkali concentration in the reactor reach 1.2-2.0mol / L, and then feed oxygen, air, or a mixed gas of oxygen and nitrogen to make the pressure reach 0.01- 0.5MPa, adjust the stirring speed to make the gas-liquid ratio in the reactor meet the requirements and ensure that the pressure in the reactor is 0.05-0.3MPa, and control the temperature in the reactor to oxidize and synthesize benzyl under the condition of 45-50°C; (2) Add the weight of The raw material is 10-12 times water, and alkali is added so that the alkali concentration in the kettle is 0.5-1.0mol / L, and then the temperature is raised to 75-85°C, and th...

Embodiment 2

[0019] Example 2, in the method for synthesizing the DSD acid oxidation intermediate by the water phase pressurization method described in Example 1: the reaction kettle is a self-priming agitator or a loop reactor. The fluid near the self-priming agitator also moves in a circle under the action of the impeller, and the centrifugal force generated generates suction to the inside of the agitator, so that a negative pressure zone is formed inside the agitator, and the inside of the agitator is connected with the gas phase through a hollow shaft. Connected, so that the gas on the liquid surface is continuously sucked into the agitator and re-dispersed in the liquid phase. The self-priming agitator has the ability of gas self-priming, and the bubbles are well dispersed, which can greatly increase the gas holdup and the contact area of ​​the gas-liquid phase, and can significantly increase the reaction rate for most gas-liquid reactions. The loop reactor consists of a high-pressure...

Embodiment 3

[0020] Embodiment 3, in the method for synthesizing the DSD acid oxidation intermediate by the aqueous phase pressurization method described in embodiment 1 or 2: the alkali is sodium hydroxide or potassium hydroxide. The sodium hydroxide or potassium hydroxide is solid or solution of sodium hydroxide or potassium hydroxide.

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Abstract

The invention relates to a method for synthetizing a DSD acid (4,4'-diamino-2,2'-stilbenedisulfonic acid) oxidation intermediate by a water phase pressurization method. The method comprises the following steps that (1) raw materials of nitrotoluene o-sulfonate and catalysts are added into a reaction kettle according to a mass ratio of 1 to (0.001 to 0.01); water with the weight being 5 to 6 times of that of the raw materials is added; then, alkali is added, so that the concentration of the alkali in the reaction kettle reaches 1.2 to 2.0mol / L; oxygen gas, air or mixed gas of oxygen gas and nitrogen gas is introduced, so that the pressure reaches 0.01 to 0.5MPa; (2) water with the weight being 10 to 12 times of that of the raw materials is added; the alkali is added, so that the concentration of the alkali in the kettle reaches 0.5 to 1.0 mol / L; then, the temperature is raised to 75 to 85 DEG C; a double-bond compound is synthetized through oxidation. The method has the advantages that a step-by-step method is used; firstly, a single-bond compound is synthetized at low temperature; then, the single-bond compound is dehydrogenized to synthetize the double-bond compound; the possibility of by-product formation due to bond breaking of the double-bond compound in a high-temperature state for a long time is reduced.

Description

technical field [0001] The invention relates to a synthesis technology of DSD acid, in particular to a method for synthesizing an oxidation intermediate of DSD acid by an aqueous phase pressurization method. Background technique [0002] The full name of DSD acid is 4,4'-diaminostilbene-2,2'-disulfonic acid, which is an important dye intermediate in the field of fine chemicals and the main raw material for the production of stilbene series optical brighteners; It is also an important intermediate of direct dyes and reactive dyes, and can produce hundreds of varieties such as direct frozen yellow G, direct brilliant yellow 4R, reactive bright yellow KD-3G, and fast orange F3G. The synthesis of DSD acid generally adopts the steps of sulfonation, oxidation, reduction, and acid analysis: the raw material p-nitrotoluene is sulfonated with oleum to obtain p-nitrotoluene orthosulfonic acid (NTS), which is oxidized and condensed into 4,4'-di Sodium nitrostilbene-2,2'-disulfonate (D...

Claims

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Application Information

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IPC IPC(8): C07C303/22C07C309/40
Inventor 李将刘肖晖王国森
Owner 连云港莱亚化学有限公司
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