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Method for producing ADC (azodicarbonamide) foaming agent by chlorine dioxide biurea

A technology of ADC foaming agent and biuret is applied in the field of producing ADC foaming agent by oxidizing biuret with chlorine gas, which can solve the problems of high reaction control requirements, wide product particle size distribution, low gas generation, etc., so as to reduce peroxide Effects of side reactions, reduction of particle size distribution width, and reduction of COD content

Inactive Publication Date: 2013-07-10
HANGZHOU HI TECH FINE CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] At present, the industrial production of ADC foaming agent is generally oxidized by chlorine gas, and sodium bromide is used as the catalyst. There are problems such as high requirements for reaction control, prone to overoxidation, wide particle size distribution of the product, and relatively low gas generation.

Method used

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  • Method for producing ADC (azodicarbonamide) foaming agent by chlorine dioxide biurea
  • Method for producing ADC (azodicarbonamide) foaming agent by chlorine dioxide biurea

Examples

Experimental program
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Effect test

Embodiment 1

[0017] Weigh 150 g of biurea, beat it into a biurea slurry with a solid content of 30% with industrial water, then add 1.5 g of sodium bromide therein, and stir to dissolve it. Pour the slurry into a 1L covered glass reactor with a built-in coil. Coolant is passed through the coil to control the temperature of the reaction system at 35°C. The exhaust port on the top of the cover is connected to the exhaust fan to maintain a slight negative pressure in the reactor. Chlorine gas is fed into the bottom of the reactor after being vaporized by the liquid chlorine cylinder, and the speed of chlorine gas feeding is based on maintaining a slight negative pressure in the reactor. Until the reaction is finished, the slurry is filtered, washed, and dried to analyze the gas generation and particle size.

Embodiment 2

[0019] The filtered mother liquor of Example 1 is mixed with a certain amount of industrial water to form a dilute hydrochloric acid solution with an HCl content of 5%. Weigh 150 g of the same batch of biurea, and then beat the biurea slurry with 5% dilute hydrochloric acid solution, then add 1 g of sodium bromide and 0.5 g of ferric chloride, and stir to dissolve it. Pour the slurry into a 1L covered glass reactor with a built-in coil. Coolant is passed through the coil to control the temperature of the reaction system at 35°C. The exhaust port on the top of the cover is connected to the exhaust fan to maintain a slight negative pressure in the reactor. Chlorine gas is fed into the bottom of the reactor after being vaporized by the liquid chlorine cylinder, and the speed of chlorine gas feeding is based on maintaining a slight negative pressure in the reactor. Until the reaction is finished, the slurry is filtered, washed, and dried to analyze the gas generation and particle...

Embodiment 3

[0021] The filtered mother liquor of Example 1 is mixed with a certain amount of industrial water to form a dilute hydrochloric acid solution with an HCl content of 5%. Weigh 150g of the same batch of biurea, and then use 5% dilute hydrochloric acid solution to form a biurea slurry, then add 0.5g of sodium bromide and 1g of ferric chloride, and stir to dissolve it. Pour the slurry into a glass reactor with a cover and a coil with a volume of 1 L, and a refrigerant is passed through the coil to control the temperature of the reaction system at 40°C. The exhaust port on the top of the cover is connected to the exhaust fan to maintain a slight negative pressure in the reactor. Chlorine gas is fed into the bottom of the reactor after being vaporized by the liquid chlorine cylinder, and the speed of chlorine gas feeding is based on maintaining a slight negative pressure in the reactor. Until the reaction is finished, the slurry is filtered, washed, and dried to analyze the gas gen...

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Abstract

The invention discloses a method for producing an ADC (azodicarbonamide) foaming agent by chlorine dioxide biurea. The method concretely comprises the following steps of A, adding a part of water to biurea, recovering a part of oxidized mother liquor to prepare 20-40% biurea slurry containing acid, adding an oxide additive of which the mass ratio of the biurea is 0.3-10%; B, adding the biurea slurry into an oxidizing kettle, exhausting by an exhaust fan, keeping micro-negative pressure inside the oxidizing kettle, namely -1 to -10kPa; C, opening a chlorine valve, leading chlorine, and controlling the reaction temperature at 20-60 DEG C by a refrigerant, oxidizing until the reaction is finished; keeping the micro-negative pressure inside the oxidizing kettle in an oxidizing process; D, separating, washing and drying the slurry to prepare the product ADC foaming agent after the reaction is finished; recycling a part of oxidizing mother liquor, and carrying out wastewater treatment on a part of oxidizing mother liquor. The method has the beneficial effects that the quality of the ADC product is improved by adopting these methods; the particle size distribution width is reduced; the gas forming amount is improved; a reaction terminal point is easier to control; the peroxide phenomenon is reduced; the product yield is improved; the peroxide side reaction is reduced; and the COD (chemical oxygen demand) content of the waste liquid is also reduced.

Description

technical field [0001] The invention relates to the field of ADC foaming agents, in particular to a method for producing ADC foaming agents by oxidizing biurea with chlorine gas. Background technique [0002] ADC foaming agent (azodicarbonamide) is the most widely used general-purpose foaming agent in foam products. It is widely used in Plastic products such as polyethylene, polyvinyl chloride, polystyrene, polypropylene, ABS resin and EVA, and rubber products. [0003] At present, the industrial production of ADC foaming agents generally uses chlorine gas oxidation and sodium bromide as the catalyst, which has problems such as high requirements for reaction control, prone to overoxidation, wide particle size distribution of the product, and relatively low gas generation. Contents of the invention [0004] The purpose of the present invention is to overcome the deficiencies in the prior art, and provide a method for producing ADC foaming agent by chlorine gas oxidation of...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C281/20
Inventor 陈海贤魏增
Owner HANGZHOU HI TECH FINE CHEM
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