Method for recovering tetrahydrofuran from waste solvent

A technology for tetrahydrofuran and waste solvents, which is applied in the field of purification and recovery of tetrahydrofuran and recovery of tetrahydrofuran in waste solvents, can solve the problems of complex process and high cost, achieve good purity, low price, and reduce the harm to human body and environment

Pending Publication Date: 2021-10-01
JIANGSU YINGTIAN CHEM
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Problems solved by technology

[0006] The technical problem to be solved by the present invention is to provide a method with simple process, convenient operation, low cost, environmental protection and high yield for the problems of complex process, high cost, low yield and purity in the process of purifying and recovering THF from hazardous waste solvents. High-efficiency high-purity tetrahydrofuran purification and recovery process, this process can purify and recover tetrahydrofuran in hazardous waste solvents, the recovery rate can reach more than 92%, the purity can reach more than 99.95%, and the water content is less than 200ppm, which can meet the requirements of industrial grade tetrahydrofuran

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  • Method for recovering tetrahydrofuran from waste solvent

Examples

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preparation example Construction

[0032] The preparation method of described hydrophilic polyaniline pervaporation membrane is:

[0033]Add deionized water to the reactor, then add aniline with 10% to 15% deionized water quality into the reactor, stir continuously, then mix sulfuric acid and sulfosalicylic acid in a molar ratio of 1:4 to obtain a mixed acid, Add excess mixed acid to the reaction kettle, aniline reacts with acid to generate soluble sulfate, and add ammonium persulfate 1.5 times the quality of aniline dropwise to the generated sulfate solution at a rate of 5mL / min under constant stirring solution, after adding ammonium persulfate, the color of the solution gradually changes from light yellow to green, and as the reaction continues, the color of the solution gradually deepens and finally turns emerald green. Control the reaction temperature at 20°C for polymerization for 6 hours. Filter, and successively wash and filter with compound acid, absolute ethanol, and distilled water until the filtrate ...

Embodiment 1

[0039] The feed flow rate of tetrahydrofuran-methanol-water mixed liquid is 1000kg / h, and the mass composition is: tetrahydrofuran 70%, methanol 25%, water 5%. The solution is preheated to 60°C by a heater, and then added to an atmospheric rectification column for extraction and rectification. Ethylene glycol was added as an extractant. The feed ratio of the extractant to the tetrahydrofuran-methanol-water mixture was 1.5:1, the reflux ratio was controlled to be 6, the heating temperature of the tower bottom was 75°C, and the temperature at the top of the tower was 64.7°C. The number of trays in the atmospheric rectification column is 55, and the number of trays in the high-pressure rectification column is 38. The extraction agent is ethylene glycol. For ethylene glycol, methanol and water. The ethylene glycol at the bottom of the tower is sent to the separation tower for separation, and the ethylene glycol is recycled. Send the azeotrope discharged from the top of the towe...

Embodiment 2

[0041] The feed flow rate of tetrahydrofuran-methanol-water mixture is 1200kg / h, preheated to 60°C by a heater, and its mass composition is: 50% tetrahydrofuran, 40% methanol, and 10% water. The feed ratio of extractant to tetrahydrofuran-methanol-water mixture is 2:1, rectification at atmospheric pressure, the control reflux ratio is 6, the number of trays in the rectification column at atmospheric pressure is 55, and the number of trays in the high-pressure rectification column is 38 blocks, the heating temperature of the tower bottom is 78°C, the temperature at the top of the tower is 63.4°C, the extraction agent is ethylene glycol, the top discharge is an azeotrope containing a large amount of tetrahydrofuran and a small amount of methanol, and the bottom discharge is ethylene glycol, methanol and water. The ethylene glycol at the bottom of the tower is sent to the separation tower for separation, and the ethylene glycol is recycled. The azeotrope discharged from the top ...

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Abstract

The invention relates to the technical field of purification and recovery of hazardous waste solvents, in particular to a method for purifying and recovering tetrahydrofuran, and particularly relates to a method for recovering tetrahydrofuran from a waste solvent. The method comprises the following steps: preheating raw materials, feeding the preheated raw materials into a normal-pressure rectifying tower taking ethylene glycol as an extracting agent, obtaining an azeotrope of tetrahydrofuran and methanol at the tower top of the normal-pressure rectifying tower, and obtaining a product which is a mixture of water, methanol and ethylene glycol in a tower kettle. The mixture enters an extraction agent recovery tower, and the extraction agent is recovered and recycled. The azeotrope enters a high-pressure tower, tetrahydrofuran with relatively high purity is obtained at a tower kettle, azeotrope containing a small amount of tetrahydrofuran and methanol is obtained at the top of the high-pressure rectifying tower, and the azeotrope at the top of the high-pressure rectifying tower is sent to normal-pressure extractive distillation for circular distillation, so that the product recovery rate is increased.

Description

technical field [0001] The invention relates to the technical field of purification and recovery of hazardous waste solvents, in particular to a method for purification and recovery of tetrahydrofuran, in particular to a method for recovery of tetrahydrofuran in waste solvents. Background technique [0002] At present, as a polar aprotic solvent, tetrahydrofuran (THF) has the characteristics of clarity, low viscosity, low boiling point, strong stability, good fluidity, and good solubility to many organic substances. Therefore, it is used in the chemical industry, especially It is widely used in organic synthesis, drug synthesis and polymer synthesis. [0003] Tetrahydrofuran can be miscible with water in any ratio, and it is also a solvent that is easy to absorb water. After absorbing water, it has a great impact on chemical reactions. The dehydration cost of recovering tetrahydrofuran is high, which reduces the economy of recovering tetrahydrofuran. In addition, the boilin...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D307/06
CPCC07D307/06
Inventor 杨水清董玉杰李勇庄可徐啸
Owner JIANGSU YINGTIAN CHEM
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