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Nitric acid loop oxidation device and selective oxidation of dimethyl nitrobenzene in device

A technology of dimethylnitrobenzene and oxidation device, which is applied in the field of environmental protection and safety production, and can solve problems such as COD increase, production safety cannot be guaranteed, and product yield reduction

Inactive Publication Date: 2019-10-08
上海泰初化工技术有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] Oxidation with acetic acid as the medium is usually carried out in a special autoclave containing rare metals. The raw materials, acetic acid and catalyst are placed in the autoclave, and air and oxygen at a certain pressure are introduced into the autoclave. After a certain period of reaction, the acetic acid is distilled out to obtain the product The disadvantage of this production process is that the oxidation of nitroxylene cannot be controlled to stay in the stage of nitromonomethylbenzoic acid, and nitromonomethylbenzoic acid will continue to be deeply oxidized by oxygen to form nitrophthalic acid after it is generated, thereby The yield of the product is greatly reduced; the oxidation reaction with dilute nitric acid as the medium usually uses a tank reactor to mix the raw material and the oxidant, and directly oxidizes at a certain temperature to obtain nitromonomethylbenzoic acid. The disadvantages of this type of production process In addition to the fact that the oxidation cannot stay at the stage of nitromonomethylbenzoic acid, the more important thing is that nitrophthalic acid will be further oxidized and decomposed (digested), and a large amount of organic matter will be decomposed, which will greatly increase the COD in the wastewater, and at the same time the waste gas contains NO x , if a closed high-pressure reaction system is used, the pressure will be 8-10MPa
Production safety cannot be guaranteed

Method used

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  • Nitric acid loop oxidation device and selective oxidation of dimethyl nitrobenzene in device
  • Nitric acid loop oxidation device and selective oxidation of dimethyl nitrobenzene in device
  • Nitric acid loop oxidation device and selective oxidation of dimethyl nitrobenzene in device

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] Embodiment 1, 3-nitro o-xylene oxidation preparation 3-nitro-2-methylbenzoic acid

[0023]

[0024] Put 400 kilograms of 30% nitric acid, 25 grams of catalyst and 100 kilograms of 3-nitroxylene raw materials into a 1000L reactor, heat up to 110°C-120°C, wait until the pressure of the reactor rises to 0.3MPA, turn on the circulation pump, and the mixture Pour into a 200-liter separation tank. When the liquid level in the separation tank reaches a certain height, the controller closes valve 2 and opens valve-1, so that the liquid directly flows back to the reactor, and the system forms an internal cycle. Open the gas valve -3, adjust the pressure of air or oxygen at 0.4MPA, the liquid in the separation tank and air or oxygen are pressed into the reaction kettle, the excess gas is released from the pressure relief valve, and the liquid in the separation tank is emptied Finally, the controller automatically opens valve-2, closes valve-1, and so on. After 15 hours of reac...

Embodiment -2

[0025] Example-2, 4-Nitro-o-xylene Oxidation Preparation of 4-Nitro-3-Methylbenzoic Acid

[0026]

[0027] Put 500 kilograms of 20% nitric acid, 25 grams of catalyst and 100 kilograms of 4-nitro-o-xylene raw materials into a 1000L reactor, heat up to 110°C-120°C, and wait until the pressure of the reactor rises to 0.3MPA, turn on the circulation pump, The mixture is poured into a 200-liter separation tank. When the liquid level in the separation tank reaches a certain height, the controller closes valve 2 and opens valve-1, so that the liquid flows back directly to the reactor, and the system forms an internal cycle. Open the gas valve-3, adjust the pressure of air or oxygen at 0.4MPA, the liquid in the separation tank and air or oxygen are slowly pressed into the reaction kettle, the excess gas is released from the pressure relief valve, and the liquid in the separation tank is discharged After emptying, the controller automatically opens valve-2 and closes valve-1, and th...

Embodiment -3

[0028] Example-3 Preparation of 3-methyl-4-nitrobenzoic acid by oxidation of 4-nitro-m-xylene

[0029]

[0030]Put 400 kilograms of 30% nitric acid, 25 grams of catalyst and 100 kilograms of 4-nitro-m-xylene raw materials into a 1000L reactor, heat up to 110°C-120°C, wait until the pressure of the reactor rises to 0.3MPA, turn on the circulation pump, The mixture is poured into the 200-liter separation tank. When the liquid level of the separation tank reaches a certain height, the controller closes the valve-2 and opens the valve-1, so that the liquid directly flows back to the reactor, and the system forms an internal cycle. Open the gas valve -3, adjust the pressure of air or oxygen at 0.4MPA, the liquid in the separation tank and air or oxygen are pressed into the reaction kettle, the excess gas is released from the pressure relief valve, and the liquid in the separation tank is emptied Finally, the controller automatically opens valve-2, closes valve-1, and so on. Afte...

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Abstract

The invention discloses a nitric acid loop oxidation device and selective oxidation of dimethyl nitrobenzene in the device. The device is characterized in that the device (as shown in the attached drawings of the specification) consists of 1, a reaction kettle 2, a condenser 3, a pressure relief valve 4, a circulation pipeline 5, an air or oxygen steel cylinder or storage tank 6, a circulation pump 7, a filter pressing tank 8, a spray head 9, a valve III 10, a controller 11, a valve I 12, a valve II 13 and a pressure reducing valve. The selective oxidation of dimethylnitrobenzene is carried out in the device, and the result shows that the device can selectively oxidize the nitromonomethylbenzoic acid generated by dimethylnitrobenzene with high yield and high selectivity. At the same time,nitric acid is recycled by using the principle that oxygen reacts with nitrogen oxides and water to generate nitric acid, the emission of nitrogen oxides is greatly reduced, the total pressure of thereaction system is reduced, and the safety is improved.

Description

technical field [0001] The invention relates to a loop nitric acid oxidation device, which belongs to the fields of environmental protection and safe production. It specifically relates to a loop reaction device, which can effectively separate the nitromethylbenzoic acid generated by catalytic oxidation of dimethylnitrobenzene with air or oxygen in dilute nitric acid from the system, thereby No deeply oxidized nitrodiacids are produced. [0002] technical background [0003] Nitromonomethylbenzoic acid is a class of very valuable compounds, 3-methyl-4-nitrobenzoic acid is an important intermediate for the synthesis of antihypertensive drug telmisartan, 2-methyl-3-nitrobenzoic acid 2-methyl-4-nitrobenzoic acid is the main intermediate for the synthesis of insecticide methoxyfenozide, and 2-methyl-4-nitrobenzoic acid can be used to synthesize a series of antitumor drugs. Usually, the production of this kind of compound is prepared by oxidation of nitroxylene. There are two ma...

Claims

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Application Information

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IPC IPC(8): B01J19/18B01J4/00C07C201/12C07C205/57
CPCB01J4/001B01J19/0053B01J19/1881C07C201/12C07C205/57Y02P20/10
Inventor 谭昊明谭佳楣吴哲青其他发明人请求不公开姓名
Owner 上海泰初化工技术有限公司
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