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A method for preparing 4,4'-dinitrostilbene-2,2'-disulfonic acid

A technology of dinitrostilbene and disulfonic acid, applied in the preparation of sulfonic acid, organic chemistry, etc., can solve the problems of complex solvent recovery process, unsuitable for industrial production, heavy air drying load, etc., and achieve strong industrial practical value, Improved oxygen utilization rate and short reaction time

Active Publication Date: 2015-09-09
中国中化股份有限公司 +1
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Although this method has the advantages of stable solvent, low consumption of alkali and catalyst, and high yield, it needs to blow dry air to cause heavy air drying load, and the solvent loss caused by air entrainment is large, and the mixed alcohol used in lye is consumed. Larger, resulting in high production costs, not suitable for industrial production
Since then, Bayer has also published a series of patents on the synthesis of DNS by the solvent method, which mainly uses a mixed medium of organic solvent and water. Although the yield can reach more than 90%, in addition to the shortcoming of air entrainment loss, it is also There are problems of complicated solvent recovery process and high production cost
In addition, the dye industry [J]. 2001 (03) reported the method of using a liquid jet loop reactor to oxidize and synthesize DNS in a non-aqueous medium. Due to the low selectivity of the reaction, it is also difficult to realize industrial production.
[0005] So far, there is no report on the preparation of DNS by solvent method suitable for industrialization at home and abroad.

Method used

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  • A method for preparing 4,4'-dinitrostilbene-2,2'-disulfonic acid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] In a 500ml reaction kettle with a cooling jacket and a self-priming stirrer, add 150g dimethyl sulfoxide, 30.5g sodium p-nitrotoluene o-sulfonate, 0.05g Mn(OAc) 2 .4H 2 O was stirred and dissolved, the system was closed, and the O in the reactor was 2 with N 2 Adjust the ratio of mixed gas to 22:78 (or pass through dry air), pressure 520mmH 2 O column, connected to the oxygen storage tank, adjust the stirring speed so that the gas holdup (volume) in the reaction solution reaches 20%, under the condition of 18-20°C, add 4.0g of 22.95% NaOH methanol solution to the system within 5min, and at the same time add Oxygen is supplemented in the system and the internal temperature of the system is maintained at 520mmH 2O column pressure, reaction 50min, liquid chromatographic tracking monitoring raw material p-nitrotoluene o-sulfonic acid and benzyl (transition product) content of 99%. After recovering a small amount of residual solvent and products from the mother liquor, th...

Embodiment 2

[0033] The system pressure in the reaction process of Example 1 was kept floating at 400-600mm water column, other feeding and operating conditions were unchanged, the reaction was completed in 60 minutes, and the product yield was 94.6%.

Embodiment 3

[0035] The ratio of the mixed gas of oxygen and nitrogen introduced initially in Example 1 was adjusted to 50:50, other feeding and operating conditions remained unchanged, the reaction was completed in 45 minutes, and the product yield was 95.0%.

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Abstract

The invention discloses a novel method for preparing 4,4'-dinitrostilbene-2,2'-disulfonic acid or sodium salt of the 4,4'-dinitrostilbene-2,2'-disulfonic acid. A target product is obtained through a catalytic oxidation process that oxygen or mixed gas composed of oxygen and nitrogen is passed into an oxidation reaction device having a self-suction stirrer, with 4-nitrotoluene-2-sulfonic acid (NTS) or sodium salt of the 4-nitrotoluene-2-sulfonic acid being a raw material, a strong polar organic solvent being a medium, and transition metal salt being a catalyst. During a reaction process in the preparing method, solvent does not lose, reaction speed is rapid, reaction conditions are mild, reaction selectivity is good, and product yield is high.

Description

technical field [0001] The invention belongs to the field of organic synthesis, in particular to a method for preparing 4,4'-dinitrostilbene-2,2'-disulfonic acid. Background technique [0002] 4,4'-dinitrostilbene-2,2'-disulfonic acid (or sodium salt, referred to as DNS) is 4,4'-diaminostilbene-2,2'-disulfonic acid (referred to as DSD acid) is an intermediate product in the production process. For a long time, the improvement of its synthesis method has been widely concerned by people. So far, DNS at home and abroad is obtained through the oxidative condensation of p-nitrotoluene orthosulfonic acid. There are many preparation methods according to the difference of medium, alkali, oxidant and catalyst, but the oxidation process that has attracted more attention is mainly the sodium hypochlorite method. , chlorine method, water medium method (abbreviated as water method) and solvent method. Among them, the common disadvantage of the sodium hypochlorite method, the chlorine g...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C309/40C07C303/22
Inventor 郑玉安祁巍王雪梅贾晓雷
Owner 中国中化股份有限公司
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