Preparation of 2-aminophenol_Kain Industrial Additive

Background and overview^[1][2]

2-Aminophenol is also called o-aminophenol. O-aminophenol (OPA), a typical aromatic amphoteric compound, is an important chemical intermediate and is widely used in dyes, medicine, printing industry and biological fields.

Preparation^[1]

The main preparation processes of 2-aminophenol include iron powder reduction, hydrogenation reduction, nitrification and reduction, and sodium sulfide reduction. Its traditional synthesis method is to use o-nitrochlorobenzene as raw material, hydrolysis and reduction of iron powder. During the reduction process, the three wastes are seriously polluted, and the product is wrapped in iron mud, resulting in a low product yield. Ortho-aminophenol can also be prepared using o-nitrophenol as the raw material and ethanol as the solvent. Because the solubility of o-nitrophenol (ONP) in water is too small during the reduction process, the organic solvent ethanol is mostly used in this process. However, because o-aminophenol (OAP) has a large solubility in organic solvents and is very unstable, the yield has not been high, and the cost of ethanol is also high, making the cost of this process slightly higher. When sodium sulfide is used for reduction, the yield of the product is very low, and because the wastewater contains a large amount of chloride ions, it also causes great pollution to the environment.

CN201310710958.5 provides a preparation method of o-aminophenol. First, o-nitrochlorobenzene is used as raw material, and sodium hydroxide solution is added for hydrolysis; then sodium hydrosulfide is added for reduction reaction to obtain sodium o-aminophenol, and then Add sulfuric acid solution for acidification to obtain hydrogen sulfide gas, and pass through the hydrogen sulfide absorption tower to obtain sodium hydrosulfide before putting it into production. The sulfate radicals in the solution can react with the sodium ions in sodium o-nitrophenolate to obtain sodium sulfate, which is then passed through The temperature is lowered to obtain sodium sulfate crystals; the acidified solution is filtered and then added to an alkaline solution to neutralize it to obtain the final o-aminophenol. The wastewater obtained after production contains free chloride ions, and limestone can be added to obtain calcium chloride precipitation; after the precipitation is removed, the industrial production water is obtained through activated carbon decolorization and four-effect evaporation and put into production to achieve the purpose of recycling. Figure 1 is a process flow diagram of a novel process for preparing o-aminophenol according to the present invention.

Wastewater treatment^[2]

CN201410667163.5 provides a method for treating o-aminophenol wastewater, which can effectively solve the problem of treating o-aminophenol wastewater and realize wastewater recycling and reuse. This is specifically achieved by the following steps:

(1) Wastewater pretreatment: Filter o-aminophenol wastewater to remove suspended matter and solid impurities, and adjust the pH value to 6-8 with sodium hydroxide or sulfuric acid; (2) Preparation of composite extraction agent: Compound The extraction agent is composed of bis(2-ethylhexyl)phosphate (P204), tris(octyl-decyl)alkyl tertiary amine (N235) and diluent. Among them, bis(2-ethylhexyl)phosphate The weight ratio with tri(octyl-decyl)alkyl tertiary amine is 1:1-5 (i.e., bis(2-ethylhexyl)phosphate:tris(octyl-decyl)alkyl tertiary amine=1:1-5 weight ratio ) are mixed together to form a mixture, the mixture is dissolved in the diluent, and the weight ratio of the mixture to the diluent is 1:5-10 (i.e., mixture: diluent = 1:5-10 weight ratio); the diluent is One of octanol, kerosene, chloroform or carbon tetrachloride; (3) Extraction reaction:

Add the composite extractant to the inlet of the wastewater pump, and enter the cyclone air flotation extractor (commercially available equipment, such as “Chemical Engineering” Issue 06, 2006, Beijing Heston Environmental Protection Equipment along with the pretreated o-aminophenol wastewater Co., Ltd. and the School of Resources and Environment of Lanzhou University released the “Cyclone Air Flotation Extractor”, the same below), and at the same time, air or nitrogen is introduced. Under the action of the air flow, the composite extraction agent and o-aminophenol wastewater react, and the cyclone air flotation is introduced. The air or nitrogen pressure at the bottom of the extractor is 0.01~0.2MPa, the gas volume is 0.5~80L/m3 wastewater, the reaction time of wastewater in the reactor is 0.3~1.5h, and o-aminophenol is transferred from the wastewater phase to the oil phase to achieve Oil and water are separated, the wastewater enters the ozone reaction tower, and then H2SO4 (sulfuric acid) with a mass concentration of 2-4% or HCl (hydrochloric acid) with a mass concentration of 2-4% is added to the cyclone air flotation extractor. The composite extraction agent uses H2SO4 with a mass concentration of 2-4% or HCl with a mass concentration of 2-4% to regenerate and reuse (i.e. reuse). The regeneration reaction time is 0.5-1.5h and the temperature is 20-30°C. The weight concentration ratio of the extraction agent to H2SO4 with a mass concentration of 2-4% or HCl with a mass concentration of 2-4% is 1:1-10; (4) Ozone reaction: The wastewater after oil-water separation enters the ozone reaction tower, Ozone is introduced from the bottom of the ozone reaction tower, and a catalyst is added to the wastewater at the same time. The ozone bubbles and the catalyst work together to efficiently remove the remaining small molecular organic pollutants methanol and ethanol. The wastewater can be directly reused; the wastewater entering the bottom of the ozone reaction tower The ozone pressure is 0.01~0.15MPa, and the ozone air intake volume is 0.4~70L/m³wastewater; the catalyst is ferrous sulfate, ferrous chloride or ferrous nitrate of ferrous salts etc., the mass concentration ratio of ozone to catalyst is 1-30:1-3.

The method has simple operation, low cost and good effect. The recovery rate of o-aminophenol is as high as over 99%. It not only improves the environment, but also greatly improves the recycling of resources, saves resources and has huge economic and social benefits.

Apply^[3-4]

1. Used to prepare a poly-o-hydroxyphenol antibacterial material

In daily life, pathogenic bacteria are seriously��Threatens human health. With the improvement of people’s living standards and health awareness, the development and application of antibacterial materials and products have become one of the topics of global concern. CN201310186873.1 Develop a polymerization method of aniline derivative-o-aminophenol, and use chemical oxidation method to synthesize poly-o-aminophenol; provide a new type of poly-o-aminophenol high-efficiency antibacterial material. The specific preparation method includes the following steps: (1) Prepare an acidic solution with a molar concentration of 0.1~5.0mol/L, divide it into two equal parts, add o-aminophenol to one part, and stir evenly to form liquid A, in which o-aminophenol The concentration is 0.05~1.0mol/L; add the oxidative initiator to another acidic solution and stir evenly to form liquid B. Pour liquid B into liquid A quickly at room temperature, in which o-aminophenol and the oxidative initiator The molar ratio is 10:1~0.5:1, and then react under different conditions for 4~30 hours to obtain a solid-liquid mixture; (2) The solid-liquid mixture obtained in step (1) under reduced pressure is filtered with an acidic aqueous solution, deionized Wash the filter cake with water in sequence until the filtrate is colorless; (3) Vacuum dry the solid obtained in step (2) at 60~80°C for 12 hours to obtain powdered polyo-aminophenol polymer antibacterial material. The present invention has the following advantages or positive effects: 1. The present invention adopts chemical oxidation method to synthesize polyo-o-aminophenol antibacterial material in one step, with simple preparation process and low cost, and can be used in large-scale production; 2. The anti-bacterial polyo-o-aminophenol provided by the present invention The material has an excellent antibacterial performance spectrum and has a strong antibacterial effect on both Gram-negative and Gram-positive bacteria; 3. The polyo-aminophenol antibacterial agent provided by the present invention has good thermal stability, is soluble in most common organic solvents, and is extremely applicable value.

2. Used to prepare a polymerization inhibitor used in the thermal dimerization process of petroleum cracking carbon five fractions

CN201010535960. This polymerization inhibitor is particularly suitable for the thermal dimerization process of diolefins in the carbon five fraction of petroleum cracking. It can effectively inhibit the self-polymerization or copolymerization of diolefins in the thermal dimerization reactor and the blocking of the preheater. It captures free radicals and adjusts the molecular weight of the polymer, so that the logistics has better fluidity; during the thermal dimerization process of the petroleum cracking carbon five fraction, it can effectively reduce the isopentene conversion rate without affecting the cyclopentadiene conversion rate. diene loss rate, and at the same time it is easy to separate the diene system.

Main reference materials

[1] CN201310710958.5 A new process for preparing o-aminophenol

[2] CN201410667163.5 A method for treating o-aminophenol wastewater

[3] CN201310186873.1 A poly-o-hydroxyphenol antibacterial material and its preparation method

[4] CN201010535960.X A polymerization inhibitor used in the thermal dimerization process of petroleum cracking carbon five fractions