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Method for separating and purifying triethylene diamine

A technology of triethylenediamine and rectification tower, which is applied in the field of separation and purification of fine chemicals, can solve the problems of increased distillation difficulty, blockage of pipelines, cumbersome process, etc., and achieve the effect of less process equipment and high recovery rate

Inactive Publication Date: 2015-01-28
RUIAN PULUO BIOTECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] At present, the main raw materials for the preparation of triethylenediamine are N-hydroxyethylpiperazine, ethylenediamine, ethanolamine, piperazine, etc. Triethylenediamine itself has a melting point of 159.8°C and a boiling point of 174°C, and the temperature range in which it exists in a liquid state is only 14.2°C, resulting in the easy crystallization of triethylenediamine and blockage of the pipeline, thus increasing the difficulty of distillation
Most patents use the way of quenching triethylenediamine to prepare pure product solution. In the prior art, the method of quenching and purifying triethylenediamine is generally used, but in this method, the evaporator needs to be heated or kept warm, and the product is obtained for the first time. The purity is not high, it needs to be further vaporized and condensed in a solvent with a high boiling point, the equipment investment is high, the energy consumption is large, and the process is cumbersome

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0015] Diethylenetriamine reacts with a catalyst composed of 86% silicon dioxide and 12% aluminum oxide at normal pressure and a temperature of 360°C to obtain triethylenediamine and piperazine mixture (the mass content of triethylenediamine is 75%) ) is fed from the middle of the tower, and the flow rate is 5ml / min. The extraction agent 1-chloro-n-hexane is fed from the top of the tower, and the flow rate is 20ml / min. ℃~160℃, reflux ratio 2, the top distillate is the azeotrope of triethylenediamine, piperazine and extractant, and the distillate in the bottom of the tower is triethylenediamine; the top distillate of the first rectification tower enters the second distillation Distillation tower for separation, the operating pressure of the second distillation tower is 50kPa ~ 150kPa, the temperature of the tower top is 135°C ~ 180°C, the temperature of the tower bottom is 140°C ~ 200°C, the reflux ratio is 5, and the content of triethylenediamine in the top fraction is relative...

Embodiment 2

[0017] Diethylenetriamine reacts with a catalyst composed of 86% silicon dioxide and 12% aluminum oxide at normal pressure and a temperature of 360°C to obtain a mixture of triethylenediamine and piperazine (the mass content of triethylenediamine is 65%) ) from the middle of the first rectification tower, the flow rate is 6ml / min, the extractant 1-chloroheptane is fed from the top of the tower, the flow rate is 30ml / min, the operating pressure is 28kPa, and the temperature at the top of the tower is 80°C to 150°C , the temperature at the bottom of the tower is 90°C to 160°C, the reflux ratio is 4, the overhead distillate is the azeotrope of triethylenediamine, piperazine and extractant, and the bottom fraction is triethylenediamine; the top of the first rectification tower The fraction enters the second rectification tower for separation. The operating pressure of the second rectification tower is 50kPa-150kPa, the tower top temperature is 135°C-180°C, the tower bottom temperat...

Embodiment 3

[0020] Diethylenetriamine reacts with a catalyst composed of 86% silicon dioxide and 12% alumina at normal pressure and a temperature of 360° C. to obtain triethylenediamine and piperazine mixture (the mass content of triethylenediamine is 70% ) from the middle of the tower, the flow rate is 7ml / min, the extraction agent 1-chloro-n-octane is fed from the top of the tower, the flow rate is 40ml / min, the operating pressure is 28kPa, the temperature at the top of the tower is 80 ° C ~ 150 ° C, the temperature 90 ℃ ~ 160 ℃, reflux ratio 8, the top fraction is triethylenediamine, piperazine and extractant azeotrope, the bottom fraction is triethylenediamine; the top fraction of the first rectification tower enters the second Separation is carried out in the rectification tower, the operating pressure of the second rectification tower is 50kPa~150kPa, the temperature of the tower top is 135℃~180℃, the temperature of the tower bottom is 140℃~200℃, the reflux ratio is 4, and the conten...

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PUM

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Abstract

The invention discloses a method for separating and purifying triethylene diamine. The method comprises the following steps: adding an extraction agent for extraction and distillation into a mixture of triethylene diamine and piperazine, and feeding the components into a first rectifying tower for separation, thereby obtaining an overhead fraction, namely, azeotrope of triethylene diamine, piperazine and the extraction agent, and a bottom fraction, namely, triethylene diamine; feeding the overhead fraction of the first rectifying tower into a second rectifying tower for separation, circulating an overhead fraction to the first rectifying tower, and collecting a bottom fraction, namely, triethylene diamine; combining the bottom fractions of the first rectifying tower and the second rectifying tower; subsequently adding a cyclomethylamine-containing compound which accounts for 38% of the mass of triethylene diamine into the bottom fractions to be used as an entrainer; adding the above components into the bottom of a third rectifying tower, rectifying under the conditions that the absolute vacuum degree is 38kPa and the temperature of a bottom reaction liquid is 125 DEG C, controlling the reflux ratio to be 0.15 to 1, and collecting the fraction before 115 DEG C, wherein the number of theoretical plates of the third rectifying tower is 38. In the separation and purification process, the extraction gent is not azeotropic with the mixture of triethylene diamine and piperazine and crystals are not generated.

Description

technical field [0001] The invention relates to the technical field of separation and purification of fine chemicals, in particular to a method for separation and purification of triethylenediamine. Background technique [0002] Triethylenediamine (TEDA) is an important industrial chemical widely used as a blowing agent for polyurethane soft, semi-rigid, rigid foams and elastomers. It is the most widely used and the largest amount of polyurethane catalyst in the polyurethane industry. [0003] At present, the main raw materials for the preparation of triethylenediamine are N-hydroxyethylpiperazine, ethylenediamine, ethanolamine, piperazine, etc. Triethylenediamine itself has a melting point of 159.8°C and a boiling point of 174°C, and the temperature range in which it exists in a liquid state is only 14.2°C, triethylenediamine is easily crystallized and the pipeline is blocked, thereby increasing the difficulty of distillation. Most patents use the way of quenching triethyl...

Claims

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Application Information

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IPC IPC(8): C07D487/08
CPCC07D487/08
Inventor 杨钟华
Owner RUIAN PULUO BIOTECH