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Method for recycling cyanoacetamide in mother liquor

A technology of cyanoacetamide and recovery method, which is applied in the direction of carboxylic acid nitrile purification/separation, organic chemistry, etc., can solve the problems of large workload and processing cost of wastewater treatment, material waste environment, material viscosity, etc., and achieves economical increase. Benefit and environmental benefits, high recycling rates, reduced emissions

Active Publication Date: 2014-11-05
NANTONG NABAIYUAN CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Problems with this technology: the waste liquid still contains a lot of cyanoacetamide products and methanol, which causes material waste and environmental pollution, and also brings a lot of workload and treatment cost to wastewater treatment
If the methanol is evaporated as much as possible during the concentration, the material in the evaporator will be viscous and agglomerated, and the material cannot be discharged.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] Evaporate and concentrate 150g of the mother liquor below 90°C, evaporate about 102g of methanol, then cool down to 60°C, add 43g of water, continue to cool down to 20°C, filter and centrifuge to obtain about 38g of cyanoacetamide (about 93% content ), waste water is about 53g (COD is about 6500mg / L);

Embodiment 2

[0020] Add 1000kg of mother liquor into the 1500L reactor and stir; when the temperature of the reactor is slowly raised to about 68°C, the methanol is evaporated, and the methanol is cooled and collected by the condenser; 1000kg of mother liquor is added dropwise while evaporating, and the dropping speed is consistent with the methanol output speed. After the 1200kg mother liquor is added dropwise, continue to evaporate methanol, and the evaporation temperature is controlled below 90°C; when the temperature reaches 90~92°C, about 1490kg of methanol will be evaporated Turn off the steam, use cooling water to lower the temperature of the reactor to 58°C, then add 700kg of water to the reactor, cool down to normal temperature, filter and centrifuge to obtain about 560kg of cyanoacetamide (content about 92.5%) , about 850kg of wastewater (COD about 7800mg / L).

[0021] The solubility of cyanoacetamide in different proportions of methanol aqueous solution is different, and the pres...

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PUM

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Abstract

The invention discloses a method for recycling cyanoacetamide in mother liquor. The method comprises the following steps of: adding primary mother liquor into a reaction kettle, and stirring; slowly rising the temperature of the reaction kettle, evaporating methanol, starting to discharge methanol when the kettle temperature achieves about 65 DEG C, cooling the methanol by using a condenser and collecting the methanol; and finishing the evaporation when the temperature inside the reaction kettle achieves 90-92 DEG C; decreasing the temperature of the reaction kettle to about 50+ / -10 DEG C, subsequently adding water, toluene or heptane and the like into the reaction kettle, decreasing the temperature to 10-20 DEG C, filtering, centrifuging and drying so as to obtain a cyanoacetamide product. The method has the advantages of high recycling rate, emission reduction and pollution reduction.

Description

technical field [0001] The invention relates to a method for recovering cyanoacetamide in mother liquor. Background technique [0002] At present, in the production process of cyanoacetamide products, methanol is used as a solvent. After the reaction is completed, the product is cooled and crystallized, and then filtered and centrifuged to obtain the product and a mother liquor. The mother liquor is evaporated and concentrated below 80°C, and 60% of the methanol is evaporated, then cooled and crystallized, filtered, and centrifuged to obtain the recovered product and the secondary mother liquor, and the secondary mother liquor is discarded (go to the wastewater treatment station). For example, if the mother liquor is 1700kg, the recycled product is 185kg (content 95%), the recovered methanol is about 900kg, and the waste liquid is about 615kg to be treated at the wastewater treatment station (COD reaches about 180,000 mg / L). [0003] The problem with this technology is that...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C255/19C07C253/34
Inventor 孙冬兵朱志平张海东顾文广徐红光吴小林
Owner NANTONG NABAIYUAN CHEM
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