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Extraction-rectification recovery method of N, N-dimethylformamide

A technology of dimethylformamide and a recovery method, which is applied in the field of chemical waste solvent treatment and recovery, can solve problems such as clogging of adsorption channels, and achieve the effects of reducing process energy consumption, making the process green, and realizing industrialization.

Pending Publication Date: 2020-05-05
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, for spinning waste solvents, due to the presence of oligomers or impurities, it is easy to cause blockage of the adsorption channels, and there are certain problems in industrialization.

Method used

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  • Extraction-rectification recovery method of N, N-dimethylformamide
  • Extraction-rectification recovery method of N, N-dimethylformamide

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031]The obtained batch of N,N-dimethylformamide wastewater solvent, the concentration of N,N-dimethylformamide in it was determined to be 40%, using a single solvent octanoic acid as the extraction agent, entering from the lower part of the rotary disk extraction tower, The feed flow rate is fixed at 10ml / min, and the waste solvent enters from the upper part of the extraction tower, and the flow rate is set at 20ml / min. Set the rotary speed of the sieve-plate rotary-disk extraction tower to 40 r / min, the extraction temperature to 25° C., and obtain the extraction phase at the top of the extraction tower. The obtained extraction phase is subjected to a rectification operation, which enters from the middle of the rectification tower, and the operating pressure is controlled to be 0.75 atm, and the reflux ratio is set to 0.5. Under these operating conditions, a top fraction at a top temperature of 140.8°C was collected. Then the obtained fractions are further refined through a...

Embodiment 2

[0033] The obtained batch of N,N-dimethylformamide wastewater solvent, the concentration of N,N-dimethylformamide in it was determined to be 30%, using a single solvent octanoic acid as the extraction agent, entering from the lower part of the rotary disk extraction tower, The feed flow rate is fixed at 10ml / min, and the waste solvent enters from the upper part of the extraction tower, and the flow rate is set at 20ml / min. Set the rotary speed of the sieve plate rotary extraction tower to 60r / min, the extraction temperature to 25°C, and obtain the extraction phase at the top of the extraction tower. The obtained extraction phase is subjected to a rectification operation, which enters from the middle of the rectification tower, and the operating pressure is controlled to be 0.75 atm, and the reflux ratio is set to 0.5. Under these operating conditions, a top fraction at a top temperature of 140.8°C was collected. Then the obtained fractions are further refined through a dehydr...

Embodiment 3

[0035] The obtained batch of N,N-dimethylformamide wastewater solvent, the concentration of N,N-dimethylformamide was determined to be 15%, and a single solvent octanoic acid was used as the extraction agent, which entered from the lower part of the rotary extraction tower. The feed flow rate is fixed at 10ml / min, and the waste solvent enters from the upper part of the extraction tower, and the flow rate is set at 20ml / min. Set the rotary speed of the sieve plate rotary extraction tower to 60r / min, the extraction temperature to 25°C, and obtain the extraction phase at the top of the extraction tower. The obtained extraction phase is subjected to a rectification operation, which enters from the middle of the rectification tower, and the operating pressure is controlled to be 0.5 atm, and the reflux ratio is set to 0.5. Under these operating conditions, an overhead fraction was collected at an overhead temperature of 127.2°C. Then the obtained fractions are further refined thro...

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Abstract

The invention provides an extraction-rectification recovery method of N, N-dimethylformamide. The method comprises the following steps: firstly, extracting an N, N-dimethylformamide wastewater solution by utilizing an extracting agent, carrying out a rectification process on an obtained extract phase, recycling to obtain a high-purity N, N-dimethylformamide product at the tower top, and finally, carrying out refining steps of molecular sieve dehydration, activated carbon decoloration and the like to obtain a product meeting spinning solvent recycling requirements. The method is green in process and high in operation flexibility, compared with a rectification process, decomposition of N, N-dimethylformamide is greatly reduced, the purity of the obtained N, N-dimethylformamide product is larger than 99.9%, the recovery rate is higher than 97%, and the water content is lower than 400 ppm.

Description

technical field [0001] The invention relates to the field of chemical waste solvent treatment and recovery, and specifically relates to a N,N-dimethylformamide recovery process using a selected solvent or a composite solvent as an extraction agent and taking extraction-distillation as the core separation and recovery method. Background technique [0002] N,N-Dimethylformamide (dimethylformamide, DMF) is a transparent liquid with a faint special odor and is miscible with water and most organic solvents, so it is an organic solvent with a wide range of uses. It is used in the extraction of aromatics and for the separation and recovery of butadiene from the C4 fraction and the separation and recovery of isoprene from the C5 fraction, etc. It can also be used as an effective reagent for separating non-hydrocarbon components from paraffin. It is also widely used in the fields of medicine and pesticides and insecticides, and is often used as an important intermediate in organic sy...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C231/24C07C233/03
CPCC07C231/24C07C233/03
Inventor 秦磊蔡立鑫陈亮
Owner CHINA PETROLEUM & CHEM CORP