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Method for treating ethyl nitrite in sodium azide synthesis tail gas

A technology for the synthesis of ethyl nitrite and exhaust gas, which is applied in the direction of chemical instruments and methods, separation methods, and dispersed particle separation, can solve the problems of waste of thermal energy resources, unfavorable economic benefits, and increase the cost of nitrite removal, and achieve protection Environmental protection, saving social heat energy resources, and reducing the effect of removal costs

Active Publication Date: 2016-12-07
CHEM TECH ACAD OF SHANDONG PROVINCE
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  • Abstract
  • Description
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Problems solved by technology

[0006] The Chinese patent application "201210575718.4" discloses the technical scheme of "in a fixed bed reactor, the tail gas containing nitrite produced in the CO coupling oxalate ester is contacted with ammonia under the action of a copper-containing catalyst", and the invention The Chinese patent application titled "Method for Removing Alkyl Nitrite and Nitrogen Oxide Gas in Exhaust Gas" and application number "200610028186.7" discloses a "two-step method for absorbing alkyl nitrite. The first step is passed The alkyl alcohol is absorbed, and the unabsorbed part passes through the second part to react with the reducing gas under the condition of the supported catalyst to generate N 2 "Both the above two patent applications use metal components as catalysts, and the reaction temperature is as high as 150°C. The higher temperature greatly increases the cost of nitrite removal, which is not conducive to the economic benefits of enterprises and causes waste of thermal energy resources.

Method used

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  • Method for treating ethyl nitrite in sodium azide synthesis tail gas

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Comparison scheme
Effect test

Embodiment 1

[0032] Add 125g (2mol) mass fraction of 80% hydrazine hydrate aqueous solution and 81.6g (2.04mol) solid sodium hydroxide into 250mL ethanol, slowly feed ethyl nitrite at a rate of 30g / hour at 50°C, and the reaction time is 8 Hour. The tail gas produced is not condensed and directly passed into a two-stage absorption bottle with an absorption liquid temperature of 40°C. The two-stage absorption liquid is composed of 300g (5mol) urea + 588.7g (1.5mol) 31% hydrochloric acid + 5g ammonium nitrate + 606.3g water Prepare 20% urea acidic solution, and absorb the ethyl nitrite in the unabsorbed tail gas of the absorption device with 300mL-5°C absolute ethanol. After the reaction, the ethyl nitrite absorbed in the absolute ethanol was detected by gas chromatography, and the conversion rate of the ethyl nitrite in the tail gas in the absorption liquid was calculated to be 99.5%.

Embodiment 2

[0034] Add 125g (2mol) 80% hydrazine hydrate, 275g (2.2mol) 32% liquid caustic soda and 172.5g ethyl nitrite cooled to -5°C into the autoclave, react at 15-17°C for 10 hours, pass through the pressure regulating valve Limit the pressure in the kettle to ≤0.2Mpa, and the tail gas is not condensed and directly passed into the two-stage absorption bottle with the temperature of the absorption liquid at 40°C. The composition of the two-stage absorption liquid is 300g (5mol) urea + 588.7g (1.5mol) 31% hydrochloric acid + 5g nitric acid Ammonium + 606.3g water is configured as 20% urea acidic solution, and the ethyl nitrite in the unabsorbed tail gas of the absorption device is absorbed with 300mL-5°C absolute ethanol. After the reaction, the ethyl nitrite absorbed in the absolute ethanol was detected by gas chromatography, and the conversion rate of the ethyl nitrite in the tail gas was 99.4%.

Embodiment 3

[0036] Add 75g (1mol) of ethyl nitrite at -10°C to 150g of 80% ethanol aqueous solution, heat in a water bath at 35°C for 1 hour, and pass the generated ethyl nitrite gas directly into the two-stage absorbing liquid at 40°C without condensation. The absorption bottle, the two-stage absorption liquid is composed of 300g (5mol) urea + 588.7g (1.5mol) 31% hydrochloric acid + 5g ammonium nitrate + 606.3g water to configure a 20% urea acidic solution, the sub Absorb ethyl nitrate with 300mL-5°C absolute ethanol. After the reaction, the ethyl nitrite absorbed in the absolute ethanol was detected by gas chromatography, and the conversion rate of the ethyl nitrite in the tail gas was 99.1%.

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Abstract

The invention discloses a method for treating ethyl nitrite in sodium azide synthesis tail gas and belongs to the technical field of tail gas treatment. The method comprises the step of leading ethyl nitrite air flow into an absorption liquid containing urea, hydrogen ions and nitrate. The method is low in cost, the reaction is mild, the concentration of ethyl nitrite in the tail gas can be greatly reduced, and the treatment efficiency is 99.1%. The method can effectively protect the environment and have very good economic benefits and social benefits.

Description

technical field [0001] The invention belongs to the technical field of tail gas treatment, and in particular relates to a method for treating ethyl nitrite in the tail gas of sodium azide synthesis. Background technique [0002] Sodium azide is a fine chemical product widely used in medicine, pesticide, automobile, military, biology and other fields. The most commonly used method for the synthesis of sodium azide is the reaction of hydrazine hydrate, sodium hydroxide and ethyl nitrite. [0003] Ethyl nitrite is an extremely volatile substance with a boiling point of only 17°C. It is a flammable and explosive gas that is highly toxic to the human body and can be transformed into nitrogen oxides in the air, causing serious environmental hazards. [0004] During the synthesis of sodium azide, due to the limitation of the reaction principle, there will usually be a large amount of ethyl nitrite residue, and the tail gas containing ethyl nitrite will be formed during the post-tr...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D53/78B01D53/86B01D53/54
CPCB01D53/78B01D53/8621B01D2251/2067B01D2251/50B01D2255/70
Inventor 岳涛邢文国杨旭朱军伟王灏陈琦冯维春王瑞菲唐晓婵徐婷
Owner CHEM TECH ACAD OF SHANDONG PROVINCE
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