Method for recovering toluenediamine from waste slag emitted from production of toluene diisocyanate

A technology of toluene diisocyanate and toluene diamine, which is applied in the field of toluene diisocyanate industrial residue recycling and environmental protection, can solve the problems of high production cost, low yield, long time consumption and the like, and achieves low production cost and product yield. High, time-consuming effect

Inactive Publication Date: 2014-05-21
UNIV OF JINAN
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] Aiming at the deficiencies of the prior art, the present invention provides a method for recovering toluene diamine (TDA) with high yield and fast from the residue waste formed in the production process of toluene dii

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] Weigh 12g of crushed TDI residue and 80g of triethylenetetramine and add them to a 200mL reactor equipped with a reflux condenser, stirrer and thermometer and heat. When the temperature rises to 100°C, add 8g of TDI residue and heat To 292 ° C until the system boils, keep reflux for 30 minutes. Afterwards, 20 g of 50% NaOH aqueous solution was added at a flow rate of 20 mL / h. During the dropwise addition, the system temperature gradually dropped to 160° C., and the reaction was continued for 1 h after the dropwise addition was completed. Stop heating afterwards, cool down and discharge. The obtained product is filtered to remove the residue to obtain a dark brown filtrate, and the obtained filtrate is salted out with a saturated sodium chloride solution. The filtrate was extracted, and the amount of dichloromethane was 2 times by weight of the filtrate after salting out, and extracted 4 times in 4 equal portions.

[0035] Finally, the solvent (dichloromethane) was re...

Embodiment 2

[0037]Weigh 12g of the crushed TDI distillation residue and 40g of triethylenetetramine and add it to a reactor equipped with a reflux condenser, agitator and a thermometer and heat it. When the temperature rises to 100°C, add 8g of the TDI residue and heat it to 292°C until the system boils, keep reflux for 30min. Afterwards, 20 g of 50% NaOH aqueous solution was added at a flow rate of 20 mL / h. During the dropwise addition, the system temperature gradually dropped to 144°C. All the other steps are the same as in Example 1. The TDA yield was 65.1% of the added TDI residue.

Embodiment 3

[0039] Weigh 12g of the crushed TDI distillation residue and 80g of triethylenetetramine and add them to a reactor equipped with a reflux condenser, a stirrer and a thermometer and heat them. When the temperature rises to 100°C, add 8g of TDI residues and heat to 292°C until the system boils, keep reflux for 40min. All the other steps are the same as in Example 1. The TDA yield was 69.3% of the added TDI residue.

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PUM

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Abstract

The invention relates to a method for recovering toluenediamine (TDA) from waste slag emitted from production of toluene diisocyanate (TDI). The method comprises the steps: with triethylenetetramine as a reaction medium, performing catalysis hydrolysis on crushed TDI residue at a normal pressure by using a strong base, and completing the reaction within 3 hours; and salting out a hydrolysis product by using a saturated sodium chloride solution after filtering, extracting by using dichloromethane, and finally performing reduced pressure distillation on an extract to obtain the TDA, wherein the yield is capable of reaching above 75 percent and the purity is capable of reaching above 95 percent. According to the method, a high-pressure reactor and distillation or fractionation equipment with high cost are not needed, the reaction time consumption is short, the product yield is high, and the large-scale production of preparing the TDA through recovering of the residue of the TDI is favorably promoted.

Description

technical field [0001] The invention relates to a method for recovering toluene diamine (TDA) from residue waste formed in the production process of toluene diisocyanate (TDI), and belongs to the technical fields of preparation of toluene diamine, recycling of toluene diisocyanate industrial residues, and environmental protection . Background technique [0002] Toluene diisocyanate (TDI) is an important chemical raw material for the production of polyurethane, which is widely used in the fields of foam plastics, elastomers, coatings and adhesives. At present, the industry mainly uses toluene diamine (TDA) as a raw material to synthesize TDI through the phosgene method. When the reaction product is purified by rectification, a high-boiling distillation residue will be discharged from the bottom of the distillation tower, the main components of which are polyurea and polybiuret, containing a small amount of TDI and tar. Further heating and steaming the TDI distillation resid...

Claims

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Application Information

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IPC IPC(8): C07C209/62C07C209/84C07C211/50
Inventor 姜绪宝孔祥正张春光朱晓丽
Owner UNIV OF JINAN
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