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Edetic acid pressurization recrystallization method

An ethylenediaminetetraacetic acid, recrystallization technology, applied in chemical instruments and methods, preparation of organic compounds, organic chemistry and other directions, can solve the problems of high consumption, difficult to meet demand, complicated processes, etc., and achieve low energy consumption and high quality. Stable and less wasteful effect

Inactive Publication Date: 2016-11-09
NANJING CHEM REAGENT
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, due to the limitation of the production process, the purity of the obtained ethylenediaminetetraacetic acid is not high enough, and it is difficult to meet the needs of modern analysis and testing for high-purity ethylenediaminetetraacetic acid
[0003] The solubility of ethylenediaminetetraacetic acid in water under normal pressure is extremely small, so most of the existing purification methods of ethylenediaminetetraacetic acid are converted into sodium salt first, recrystallized, and then acidified to obtain relatively pure ethylenediaminetetraacetic acid Finished product, but a lot of acid and alkali will be consumed in the process, and a lot of deionized water will be used for washing in the later stage, the process is cumbersome and the consumption is huge

Method used

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  • Edetic acid pressurization recrystallization method
  • Edetic acid pressurization recrystallization method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] Add deionized water and ethylenediaminetetraacetic acid into the reaction device equipped with a stirrer, temperature controller and pressure gauge, the mass ratio of deionized water and ethylenediaminetetraacetic acid is 20:1, then connect nitrogen, first pass Nitrogen drives the air in the kettle clean, closes the vent valve of the reaction kettle, and then continues to pass nitrogen until the pressure in the kettle is 1 MPa, and closes the nitrogen valve. Turn on heating, start stirring when the temperature rises to 120°C, stop heating and stirring after stirring for 1 hour, open the reaction kettle when the temperature in the kettle drops to 25°C, take out the crystallized ethylenediaminetetraacetic acid, centrifuge the crystallization and separate the solution , and dried at 130°C for 3h to obtain white needle-like crystals with a yield of 93.5%. The analysis results showed that all the indicators of the EDTA recrystallized under pressure were in line with the Amer...

Embodiment 2

[0026] Add deionized water and ethylenediaminetetraacetic acid into the reaction device equipped with a stirrer, temperature controller and pressure gauge, the mass ratio of deionized water and ethylenediaminetetraacetic acid is 4:1, then connect nitrogen, first pass Nitrogen drives the air in the kettle clean, closes the vent valve of the reaction kettle, and then continues to vent nitrogen until the pressure in the kettle is 2MPa, and closes the nitrogen valve. Turn on heating, start stirring when the temperature rises to 180°C, stop heating and stirring after stirring for 3 hours, open the reaction kettle when the temperature in the kettle drops to 25°C, take out the crystallized ethylenediaminetetraacetic acid, and centrifuge the crystallization to separate the solution , and dried at 120°C for 4h to obtain white needle-like crystals with a yield of 96.1%. The analysis results showed that all the indicators of the EDTA recrystallized under pressure were in line with the Am...

Embodiment 3

[0028] Add deionized water and ethylenediaminetetraacetic acid into the reaction device equipped with a stirrer, temperature controller and pressure gauge, the mass ratio of deionized water and ethylenediaminetetraacetic acid is 7:1, then connect nitrogen, first pass Nitrogen drives off the air in the still, closes the vent valve of the reaction kettle, then continues to feed nitrogen until the pressure in the still is 1.5MPa, and closes the nitrogen valve. Turn on heating, start stirring when the temperature rises to 160°C, stop heating and stirring after stirring for 2 hours, open the reaction kettle when the temperature in the kettle drops to 28°C, take out the crystallized ethylenediaminetetraacetic acid, and centrifuge the crystallization solution Afterwards, it was dried at 80°C for 8 hours to obtain white needle-like crystals with a yield of 93.5%. The analysis results showed that all the indicators of the EDTA recrystallized under pressure were in line with the America...

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Abstract

The invention discloses an edetic acid pressurization recrystallization method. Edetic acid and water are added into a reactor, inert gas is led into the reactor to replace air in the reactor, leading of the inert gas is continued, the reactor is pressurized so that the internal pressure of the reactor is 1-2MPa, the reactor is heated to 120-180 DEG C and then cooled to form crystals, and the crystals are separated from solution and then dried to obtain recrystallized edetic acid crystals. The recrystallization method is short in integral process flow, convenient to operate, suitable for industrial production and less in raw material and energy consumption, and yield can reach 90% or more. Compared with a traditional process, less waste liquid is generated, the method is safe and environmentally friendly. The obtained edetic acid crystals are white needle crystals, stable in quality and high in purity, and various indexes conform to ACS (American chemical standards).

Description

technical field [0001] The invention belongs to the field of chemical purification, and in particular relates to a pressure recrystallization method of ethylenediaminetetraacetic acid. Background technique [0002] Ethylenediaminetetraacetic acid (EDTA) is an important complexing agent with a wide range of uses. It can be used as a bleaching and fixing solution for the processing of color photosensitive materials, dyeing auxiliaries, fiber processing auxiliaries, cosmetic additives, and blood anticoagulants , Detergent, stabilizer, synthetic rubber polymerization initiator, EDTA is a representative substance of chelating agent. However, due to the limitations of the production process, the purity of the obtained EDTA is not high enough to meet the requirements of modern analysis and testing for high-purity EDTA. [0003] The solubility of ethylenediaminetetraacetic acid in water under normal pressure is extremely small, so most of the existing purification methods of ethyle...

Claims

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Application Information

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IPC IPC(8): C07C227/42C07C229/16
CPCC07C227/42C07C229/16
Inventor 李清洁曹春
Owner NANJING CHEM REAGENT
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