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Biurea synthesis technology

A synthesis process, biurea technology, applied in the field of biurea synthesis process, can solve the problems of high treatment costs, unaffordable enterprises, large water consumption, etc., to reduce production costs, ensure non-polluting discharge, and thoroughly treat waste liquid Effect

Inactive Publication Date: 2006-02-15
KAIFENG DONGDA CHEM GROUP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0011] Due to the above synthesis process will eventually produce a large amount of waste liquid containing ammonia nitrogen, and these waste liquids also contain SO 4 -2 、CL - 、Na + Such substances have many components and complex phases. If they are treated, the treatment cost will be high and the enterprise will not be able to bear them. If they are not treated and discharged directly, they will cause serious pollution to the environment. The purity of the biurea produced by the above process is The highest can only reach 90%, and the purity is low. Adopting the method of washing to improve its purity will not only consume a lot of water, but also cost a lot. , due to the decomposition of urea and hydrazine hydrate, the yield of biurea can only reach 80%-85%, and the yield is low. Therefore, the above-mentioned problems have become a difficult problem for production enterprises for many years

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] The following production steps are used:

[0021] 1. Pretreatment of HCL gas

[0022] Pass HCL gas into it and fill it with FeCl as a reducing agent 2 Pretreatment is carried out in the filter tank to eliminate the excess oxidizing substances present.

[0023] 2. Synthesis of biurea

[0024] Add 500ml of hydrazine hydrate (hydrazine content 30g / L) into a 1000ml four-neck round-bottomed flask equipped with a mechanical stirrer, a thermometer, a reflux condenser and an air guide tube. 57g, and then feed the pretreated HCL gas through the airway until the pH value is 4, then warm to 108°C, adjust the amount of HCL gas feeding, and keep the pH value and reaction temperature to the end of the reaction (ie: in the solution hydrazine content <0.1g / L), and finally through washing, filtering and drying, 51.93g of biurea with a purity of 98% can be obtained, and the calculated reaction yield (in terms of hydrazine hydrate) is 92%.

[0025] The reaction formula in the above-me...

Embodiment 2

[0036] The following production steps are adopted:

[0037] 1. Pretreatment of hydrochloric acid

[0038] Pass HCL gas into it and fill it with FeSO as reducing agent 4 Pretreatment is carried out in the filter tank to eliminate the excess oxidizing substances, and then, the pretreated HCL gas is absorbed by water to make hydrochloric acid.

[0039] 2. Synthesis of biurea

[0040] Add 500ml of hydrazine hydrate (hydrazine content 29g / L) into a 1000ml four-necked round-bottomed flask with a mechanical stirrer, a thermometer, a reflux condenser and a constant pressure dropping funnel on it. Add 55.825g of urea in the ratio of 55.825g, and then add dropwise the pretreated hydrochloric acid (31%-36%) to the pH value of 5 through the constant pressure dropping funnel, and then heat up to 108°C to adjust the dropwise addition of hydrochloric acid. Quantity and rate of addition, keep above-mentioned pH value and temperature of reaction to the end of reaction, finally, through wash...

Embodiment 3

[0046]The following production steps are adopted:

[0047] 1. Carry out pretreatment respectively to HCL gas and hydrochloric acid, its processing method is identical with the processing method in embodiment 1, embodiment 2, but the reducing agent that adopts is Na 2 SO 3 .

[0048] 2. Synthesis of biurea

[0049] Add 500ml of hydrazine hydrate into a four-necked round-bottomed flask with a mechanical stirrer, a thermometer, a reflux condenser, and an airway tube of 1000ml. HCL gas, until the pH value is 5, replace the gas guide tube with a constant pressure dropping funnel that drips hydrochloric acid inward, raise the temperature to 107°C, adjust the amount and rate of hydrochloric acid added dropwise, and maintain the above pH value and reaction temperature to the end of the reaction (hydrazine content<0.1g / L), after washing, filtering and drying, 51.63g of biurea with a purity of 97.5% was obtained, and the calculated yield was 91% (in terms of hydrazine hydrate).

[0...

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Abstract

The synthesis technique for LDA comprises, using hydrazine hydrate and urea as material, using pretreated HCl gas without excessive oxidizing substance to replace strong H2SO4 in existing technique and prepare the said product. To treat the waste liquid, according ammonia nitrogen content in waste, caltulating required vaporated water quantity to prepare NaCl and NH4Cl, crystallizing the NaCl and NH4Cl both of high purity by evaporation and condensation respectively, and the obtained water can be recycled; returning the last little waste liquid to system for treatment with new waste liquid. This invention has little corrosion to device and high product purity and yield, and ensures the no-pollutant discharge.

Description

technical field [0001] The invention relates to a urea synthesis process, in particular to a biurea synthesis process. Background technique [0002] Biurea is an important intermediate for the production of ADC foaming agent (chemical name: azodicarbonamide), and it can also be used for anti-skid of airstrips, anti-skid of gears, fireproof and anti-solvent of advanced cables, etc. [0003] The structural formula of biurea is: [0004] [0005] In the chemical industry, the traditional process for preparing biurea is mainly based on hydrazine hydrate (N 2 h 4 ·H 2 O) and urea (CO(NH 2 ) 2 ) as raw material, according to the ratio of hydrazine hydrate and urea 1: 3.75-3.9, using concentrated H 2 SO 4 It is prepared by condensation under acidic conditions of 4-5 by controlling the pH value. The main reaction formula in the preparation process is: [0006] 1. Neutralization reaction [0007] <chemistry num="001"> <chem file="20051...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C281/06
Inventor 杨金顺陈勇张品三
Owner KAIFENG DONGDA CHEM GROUP
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