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., which can solve the problems of large workload and processing cost of wastewater treatment, material waste environment, and inability to discharge materials, etc., to achieve economical increase Benefits and environmental benefits, reduced treatment costs, reduced emissions

Active Publication Date: 2013-05-22
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 mother liquor below 90°C to distill out about 102g of methanol, then cool to 60°C, add 43g of water, continue to cool to 20°C, filter and centrifuge to obtain about 38g of cyanoacetamide (content about 93%) ), about 53g of wastewater (COD about 6500mg / L);

Embodiment 2

[0020] Add 1000kg of mother liquor to the 1500L reactor and stir; when the reactor is slowly heated to about 68℃, the methanol is evaporated, and the methanol is cooled and collected by the condenser; when the methanol starts to evaporate, slowly drip into the reactor again 1000kg mother liquor is added dropwise while evaporating. The dropping rate is consistent with the methanol output rate. After the 1200kg mother liquor is added, continue to evaporate the methanol. The evaporation temperature is controlled below 90℃; when the temperature reaches 90~92℃, about 1490kg of methanol is evaporated When about, turn off the steam, use cooling water to cool the temperature of the reactor to 58°C, then add 700kg of water to the reactor, cool to room temperature, filter and centrifuge to obtain about 560kg of cyanoacetamide (content about 92.5%) , Waste water is about 850kg (COD is about 7800mg / L).

[0021] The solubility of cyanoacetamide in different ratios of methanol aqueous solution...

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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 involves the recycling method of cyanomide in a mother liquid. Background technique [0002] At present, in the production process of cyanide acetyide products, methanol uses methanol for solvents, the reaction is over, cooling crystals, and then filtering, centrifugal, and obtained product and a parent liquid.The mother solution evaporates below 80 ° C, steams 60%of the methanol, and then cools down the crystals, filtering, and centrifugation.For example, the mother liquid is 1700kg, the recycling product is 185kg (95%), the recycling of about 900kg of methanol, and about 615kg of waste liquid to the wastewater treatment station (COD reaches about 180,000 mg / L). [0003] There are problems with this technology: The waste liquid still contains more cyanide achoinamide products and methanol, which causes material waste and environmental pollution. At the same time, it also brings a lot of workload and treatment costs to wastewater treatment.If ...

Claims

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Application Information

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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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