A process for refining and recovering mixed waste liquid containing hydroxyethylpiperazine and hydroxyethylethylenediamine

Abstract

The present invention discloses a refining and recovery process of a mixed waste liquid containing hydroxyethylpiperazine and hydroxyethylethylenediamine, firstly collects a stripping liquid waste liquid containing N-hydroxyethylpiperazine and hydroxyethylethylenediamine, adds an ether organic solvent as an extractant to the stripping liquid waste liquid and mixes it evenly, shakes and extracts it, and then stratifies it; after stratifying it, the N-hydroxyethylpiperazine-ether solution located on the upper layer and the hydroxyethylethylenediamine located on the lower layer are separated and respectively sent to a distillation tower for vacuum distillation, thereby respectively obtaining N-hydroxyethylpiperazine and hydroxyethylethylenediamine with a purity greater than 99%. Hydroxyethylpiperazine and hydroxyethylethylenediamine with similar boiling points in the stripping liquid waste liquid can be separated by the method provided by the present invention to obtain high-purity electronic chemicals.

Description

Technical Field

[0001] The invention belongs to the technical field of separation and purification of fine chemicals, and specifically relates to a refining and recovery process for mixed waste liquid containing hydroxyethylpiperazine and hydroxyethylethylenediamine. Background Art

[0002] Generally, in the manufacturing process of printed circuit boards, liquid crystal display panels, semiconductor integrated circuits, etc., it is necessary to form multiple layers of precise microcircuits on silicon wafers or glass substrates through multiple processes such as pattern mask irradiation exposure and etching. After the microcircuits are formed, the photoresist coated on the microcircuit protection area as a mask is further removed with a stripping liquid. The production process of printed circuit boards, liquid crystal display panels, etc. is complex, the process flow is long, and many chemicals are used. In the entire process, the process using stripping liquid includes photoresist removal, demolding, and degumming. Therefore, the amount of stripping liquid waste liquid generated is large. The stripping liquid waste liquid is dark black and has a strong odor. It is a mixture of organic amines and polar organic solvents, which can be recycled. A mixture of N-hydroxyethylpiperazine (HEP) and hydroxyethylethylenediamine (AEEA) is one of them. N-hydroxyethylpiperazine is an important intermediate for the production of triethylenediamine, surfactants, medicines, and pesticides. It can be used to synthesize the psychiatric drug fluphenazine. At the same time, N-hydroxyethylpiperazine is an excellent desulfurization and decarbonization agent, which can be widely used in the environmental protection industry. It can also be used as an electronic chemical in the electronics industry. Hydroxyethylethylenediamine is an important pharmaceutical and daily chemical raw material, which can be used to produce corrosion inhibitors, light stabilizers, vulcanization accelerators, and pharmaceutical intermediates such as piperazine. In terms of surfactants, cationic and zwitterionic imidazoline surfactants produced with hydroxyethylethylenediamine as raw material account for more than 90% of the total production capacity of such surfactants.

[0003] The existing stripping liquid recovery technology is mainly based on distillation, but the recovered solvent is often a mixed solvent, the product quality is low, the use value is relatively low, and its use is greatly limited. For the high-purity product recovery of HEP and AEEA stripping waste liquid, traditional distillation cannot achieve separation because the boiling points of HEP and AEEA are very close, distillation requires a lot of energy consumption, and it cannot meet the purity requirements of high-purity electronic chemicals.

[0004] The patent "A process for recovering high-purity N-methylformamide from waste stripping liquid" with publication number CN109970591A discloses a technical principle of combining melt crystallization with distillation to separate N-methylformamide (NMF) and diethylene glycol methyl ether with similar boiling points, thereby obtaining high-purity N-methylformamide; there is no mature solution in the prior art for recovering high-purity N-hydroxyethylpiperazine (HEP) and hydroxyethylethylenediamine (AEEA) from waste stripping liquid. Summary of the invention

[0005] In order to overcome the shortcomings of the prior art, the present invention provides a refining and recovery process for mixed waste liquid containing hydroxyethylpiperazine and hydroxyethylethylenediamine. According to the characteristics that HEP is miscible with ether and AEEA is slightly soluble in ether in the stripping waste liquid containing hydroxyethylpiperazine and hydroxyethylethylenediamine, HEP and AEEA are separated by extractive distillation, and high-purity mono-chemicals can be obtained after separation.

[0006] The technical solution of the present invention is as follows:

[0007] The present invention provides a refining and recovery process for a mixed waste liquid containing hydroxyethylpiperazine and hydroxyethylethylenediamine, which specifically comprises the following steps:

[0008] (1) Extraction and stratification: collecting the stripping liquid waste liquid containing N-hydroxyethylpiperazine and hydroxyethylethylenediamine, adding an ether organic solvent as an extractant to the stripping liquid waste liquid and mixing them evenly, shaking and extracting them, and then standing to separate them;

[0009] (2) Distillation: After standing and stratifying, the N-hydroxyethylpiperazine-ether solution at the upper layer and the hydroxyethylethylenediamine at the lower layer are separated and sent to a distillation tower for vacuum distillation to obtain N-hydroxyethylpiperazine and hydroxyethylethylenediamine with a purity greater than 99%.

[0010] Preferably, the boiling point of the ether organic solvent in step (1) is below 160°C, and the ether organic solvent can be selected from diethyl ether, propyl ether, butyl ether, etc.

[0011] Preferably, the volume ratio of the extractant to the stripping liquid waste is 1:(1-8). Due to the different solubilities of the selected ether organic solvents, the volume ratio of the extractant to the stripping liquid waste varies according to the selection of different ether organic solvents.

[0012] Preferably, the extraction in step (1) is carried out at room temperature, and after stirring for 1-4 hours to mix evenly, the mixture is allowed to stand for 2-8 hours to achieve stratification.

[0013] Preferably, in step (2), double-tower distillation is selected, the vacuum degree of one tower is in the range of 5-50 KPa, the tower top temperature is 45-80°C, and the tower bottom temperature is 130-170°C. Vacuum distillation is performed in one tower to remove light components, and the extractant is collected and recovered at 60-120°C on the tower side according to the boiling point of the extractant; and the second tower is subjected to vacuum distillation at an ultimate vacuum of less than 2 KPa, with a tower top temperature of 85-110°C and a tower bottom temperature of 150-180°C.

[0014] The present invention also provides a mixed waste liquid refining and recovery system containing hydroxyethylpiperazine and hydroxyethylethylenediamine, comprising an extraction tank, an N-hydroxyethylpiperazine mixed liquid tank, a hydroxyethylethylenediamine mixed liquid tank and a vacuum distillation system; the feed ports of the N-hydroxyethylpiperazine mixed liquid tank and the hydroxyethylethylenediamine mixed liquid tank are respectively connected to the side wall and the bottom of the extraction tank, and the discharge ports are respectively connected to the vacuum distillation system; the vacuum distillation system is a double-tower distillation, comprising a No. 1 distillation tower and a No. 2 distillation tower; the tower sides of the No. 1 distillation tower and the No. 2 distillation tower are both connected to a top sampling system and a discharge system, and the tower bottoms are connected to a reboiler; the No. 1 distillation tower is connected to the No. 2 distillation tower through a feed pump to achieve double-tower distillation.

[0015] Furthermore, the top sampling system includes a condenser connected to the tower kettle, a vacuum system and a reflux pump; water is collected from the top of the No. 1 distillation tower after condensation, and the distillation light components are collected from the top of the No. 2 distillation tower after condensation.

[0016] Furthermore, the discharging system includes a cooler, a collection tank, a collection pump and a vacuum system connected to the tower side; after cooling the tower side of the No. 1 distillation tower, the extractant is collected and recovered; after cooling the tower side of the No. 2 distillation tower, the refined and recovered N-hydroxyethylpiperazine and hydroxyethylethylenediamine are collected.

[0017] Compared with the prior art, the beneficial effects of the present invention are:

[0018] 1. The present invention provides a refining and recovery process for mixed waste liquid containing hydroxyethylpiperazine and hydroxyethylethylenediamine, which adopts the technical means of combining extraction and distillation, and utilizes the miscibility of HEP with ether, so as to not only solve the problem of recovering hydroxyethylpiperazine and hydroxyethylethylenediamine with similar boiling points, but also obtain hydroxyethylpiperazine and hydroxyethylethylenediamine products with high purity, which can meet the requirement of 99% purity of electronic chemicals, and overcome the technical problem of low purity of distillation recovery products in the current prior art;

[0019] 2. The amount of the extractant in the present invention will cause the loss of hydroxyethylethylenediamine. The greater the amount of the extractant, the more hydroxyethylethylenediamine will be lost, and the purity of N-hydroxyethylpiperazine will be low. On the contrary, insufficient amount of the extractant will cause low purity of hydroxyethylethylenediamine. Therefore, the volume ratio of the extractant to the stripping liquid waste liquid is designed to be 1:

[0020] (1~8);

[0021] 3. The recovery method provided by the present invention also fills the gap in the prior art regarding the high-purity recovery of hydroxyethylpiperazine and hydroxyethylethylenediamine contained in stripping waste liquid. It has a simple process and is easy to operate, and is suitable for factory production. The ether extractant can be recovered and recycled after distillation. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1This is a diagram of the HEP and AEEA recovery system in the present invention. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0024] The ether organic reagent used in the present invention is a commercially available product, and the stripping waste liquid is recycled from an electronic chemical factory.

[0025] Example 1

[0026] A process for refining and recovering a mixed waste liquid containing hydroxyethylpiperazine and hydroxyethylethylenediamine, comprising the following steps:

[0027] (1) Extraction and stratification: Collect the stripping liquid waste liquid containing N-hydroxyethylpiperazine and hydroxyethylethylenediamine, add an ether organic solvent as an extractant to the stripping liquid waste liquid and mix them evenly, shake and evenly extract at room temperature for 1 hour, and then stand for 2 hours to achieve stratification; in this embodiment, the ether organic solvent is diethyl ether, and the volume ratio of diethyl ether to the stripping waste liquid is 1:1;

[0028] (2) distillation: after standing and stratifying, the N-hydroxyethylpiperazine-ether solution in the upper layer and the hydroxyethylethylenediamine in the lower layer are separated and sent to double towers for vacuum distillation, wherein the vacuum degree of one tower is in the range of 5-20 KPa, the tower top temperature is 45-50°C, and the tower bottom temperature is 130-140°C. Vacuum distillation is carried out in the first tower to remove light components, and the extractant is collected and recovered at 60-80°C on the tower side according to the different boiling points of the extractant; the second tower is subjected to vacuum distillation at an ultimate vacuum of less than 2 KPa, the tower top temperature is 85-95°C, and the tower bottom temperature is 150-160°C, thereby obtaining N-hydroxyethylpiperazine and hydroxyethylethylenediamine with a purity greater than 99%, respectively.

[0029] Example 2

[0030] A refining and recovery process for a mixed waste liquid containing hydroxyethylpiperazine and hydroxyethylethylenediamine, specifically comprising the following steps:

[0031] (1) Extraction and stratification: Collect the stripping liquid waste liquid containing N-hydroxyethylpiperazine and hydroxyethylethylenediamine, add an ether organic solvent as an extractant to the stripping liquid waste liquid and mix them evenly, shake and evenly extract at room temperature for 4 hours, and then stand for 8 hours to achieve stratification; in this embodiment, the ether organic solvent is n-butyl ether, and the volume ratio of ether to the stripping waste liquid is 1:8;

[0032] (2) distillation: after standing and stratifying, the N-hydroxyethylpiperazine-ether solution in the upper layer and the hydroxyethylethylenediamine in the lower layer are separated and respectively sent to double towers for vacuum distillation, wherein the vacuum degree of one tower is in the range of 20-35 KPa, the tower top temperature is 65-80°C, and the tower bottom temperature is 155-170°C. Vacuum distillation is carried out in the first tower to remove light components, and the extractant is collected and recovered at 100-120°C on the tower side according to the different boiling points of the extractant; vacuum distillation is carried out in the second tower at an ultimate vacuum of less than 2 KPa, the tower top temperature is 105-110°C, and the tower bottom temperature is 170-180°C, thereby obtaining N-hydroxyethylpiperazine and hydroxyethylethylenediamine with a purity greater than 99%, respectively.

[0033] Example 3

[0034] A refining and recovery process for a mixed waste liquid containing hydroxyethylpiperazine and hydroxyethylethylenediamine, specifically comprising the following steps:

[0035] (1) Extraction and stratification: Collect the stripping liquid waste liquid containing N-hydroxyethylpiperazine and hydroxyethylethylenediamine, add an ether organic solvent as an extractant to the stripping liquid waste liquid and mix them evenly, shake and evenly shake at room temperature for 2 hours to extract, and then stand for 6 hours to achieve stratification; in this embodiment, the ether organic solvent is isopropyl ether, and the volume ratio of isopropyl ether to the stripping waste liquid is 1:2;

[0036] (2) distillation: after standing and stratifying, the N-hydroxyethylpiperazine-ether solution in the upper layer and the hydroxyethylethylenediamine in the lower layer are separated and respectively sent to double towers for vacuum distillation, wherein the vacuum degree of one tower is in the range of 35-50 KPa, the tower top temperature is 50-65°C, and the tower bottom temperature is 140-155°C. Vacuum distillation is carried out in the first tower to remove light components, and the extractant is collected and recovered at 80-100°C on the tower side according to the boiling point of the extractant; vacuum distillation is carried out in the second tower at an ultimate vacuum of less than 2 KPa, the tower top temperature is 95-105°C, and the tower bottom temperature is 160-170°C, thereby obtaining N-hydroxyethylpiperazine and hydroxyethylethylenediamine with a purity greater than 99%, respectively.

[0037] Example 4

[0038] See also Figure 1, a mixed waste liquid refining and recovery system containing hydroxyethylpiperazine and hydroxyethylethylenediamine, comprising an extraction tank, an N-hydroxyethylpiperazine mixed liquid tank, a hydroxyethylethylenediamine mixed liquid tank and a vacuum distillation system; the feed ports of the N-hydroxyethylpiperazine mixed liquid tank and the hydroxyethylethylenediamine mixed liquid tank are respectively connected to the side wall and the bottom of the extraction tank, and the discharge ports are respectively connected to the vacuum distillation system; the vacuum distillation system is a double-tower distillation, comprising a No. 1 distillation tower and a No. 2 distillation tower, the No. 1 distillation tower and the No. 2 distillation tower are connected through a feed pump, and the discharge of the No. 1 distillation tower is introduced into the No. 2 distillation tower to realize double-tower distillation; the tower sides of the No. 1 distillation tower and the No. 2 distillation tower are both connected with a top extraction system and a discharge system; the top extraction system comprises a condenser connected to the tower kettle, a vacuum system and a reflux pump; No. 1 distillation tower Water is collected from the top after condensation, and the distilled light components are collected from the top of the No. 2 distillation tower after condensation, and the vacuum system is used to maintain the vacuum state in the bottom of the tower; the bottoms of the No. 1 distillation tower and the No. 2 distillation tower are both connected to reboilers, the material liquid level in the reboiler and the liquid level in the distillation tower are at the same height, and the liquid level evaporated at the bottom of the tower is continuously replenished by the reboiler; the side of the No. 1 distillation tower is connected to the discharging system for collecting and recovering the extractant after cooling; the side of the No. 2 distillation tower is connected to the discharging system for collecting and refining N-hydroxyethylpiperazine and hydroxyethylethylenediamine after cooling; the discharging system includes a cooler connected to the tower side, a collection tank, a collection pump and a vacuum system, and the vacuum system is used to maintain the vacuum state in the bottom of the tower; the bottom of the No. 2 distillation tower is also provided with a residual liquid pump to discharge the residual liquid after distillation to the wastewater collection point.

[0039] The present invention has been described by the above-mentioned relevant embodiments, however, the above-mentioned embodiments are only examples for implementing the present invention. It must be pointed out that the disclosed embodiments do not limit the scope of the present invention. On the contrary, changes and modifications made without departing from the spirit and scope of the present invention are all within the scope of patent protection of the present invention.

Claims

1. A process for refining and recovering a mixed waste liquid containing hydroxyethylpiperazine and hydroxyethylethylenediamine, characterized in that: The specific steps include: (1) Extraction and stratification: collecting the stripping liquid waste liquid containing N-hydroxyethylpiperazine and hydroxyethylethylenediamine, adding an ether organic solvent as an extractant to the stripping liquid waste liquid and mixing them evenly, shaking and extracting them, and standing them for stratification; the extraction is carried out at room temperature, stirring for 1-4 hours to mix evenly, and standing them for 2-8 hours to achieve stratification; the ether organic solvent is diethyl ether, n-butyl ether, and isopropyl ether; (2) distillation: after standing and stratifying, the N-hydroxyethylpiperazine-ether solution in the upper layer and the hydroxyethylethylenediamine in the lower layer are separated and respectively sent to distillation towers for vacuum distillation, thereby obtaining N-hydroxyethylpiperazine and hydroxyethylethylenediamine with a purity greater than 99%; the distillation adopts double-tower distillation, the vacuum degree of one tower is in the range of 5-50 KPa, the tower top temperature is 45-80°C, the tower bottom temperature is 130-170°C, and the tower side is set with a collection temperature of 60-120°C according to the boiling point of the extractant; the second tower is subjected to vacuum distillation at an ultimate vacuum of less than 2 KPa, the tower top temperature is 85-110°C, and the tower bottom temperature is 150-180°C.

2. The process for refining and recovering a mixed waste liquid containing hydroxyethylpiperazine and hydroxyethylethylenediamine according to claim 1, characterized in that: The boiling point of the ether organic solvent in step (1) is below 160°C.

3. The process for refining and recovering a mixed waste liquid containing hydroxyethylpiperazine and hydroxyethylethylenediamine according to claim 1, characterized in that: The volume ratio of the extractant to the stripping liquid waste is 1:(1-8).

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