Method for recovering products from 2-vinylpyridine production wastewater and waste residues

Abstract

The invention discloses a method for recovering products from 2-vinylpyridine production wastewater and waste residues, and aims to realize efficient utilization and environmental protection of resources. Comprising the following steps: mixing wastewater and waste residues, dissolving the waste residues, and adding a high-temperature polymerization inhibitor to inhibit free radical polymerization reaction; the method comprises the following steps: separating a fraction containing 2-vinylpyridine through primary rectification, adding potassium carbonate into the fraction to carry out phase separation treatment, and separating to obtain an oil phase rich in 2-vinylpyridine and a water phase containing a small amount of impurities; rectifying the oil phase again to obtain a high-purity 2-vinylpyridine product, and meanwhile, recycling the water phase to the next batch of wastewater treatment; the preferable process conditions of the method are as follows: the ratio of the wastewater to the waste residue is 2: 1, the addition amount of the polymerization inhibitor is 0.5% of the total mass of the mixed material, and the primary rectification temperature is 115 DEG C; the method effectively improves the recovery rate of 2-vinylpyridine, reduces the discharge of wastewater and waste residues, reduces the production cost, is environment-friendly, and meets the requirements of green chemical production.

Description

Technical Field

[0001] The invention relates to the technical field of 2-vinylpyridine recovery, in particular to a method for recovering products from 2-vinylpyridine production wastewater and waste residues. Background Art

[0002] 2-Vinylpyridine (2VP) is an important chemical intermediate, widely used in the fields of medicine, pesticides, polymers, etc., with high added value and broad market prospects. Its molecular formula is C7H7N, and its molecular weight is 105.14. In the existing industrial production process, 2-methylpyridine is usually reacted with polyformaldehyde to generate the intermediate 2-hydroxyethylpyridine, which is then dehydrated under alkaline conditions to obtain 2VP. In this reaction process, a certain amount of wastewater and waste residue will inevitably be produced, and about 2.0%-5.0% of 2VP remains in these by-products.

[0003] In the prior art, this part of wastewater and waste residue is usually directly regarded as three wastes and disposed of by incineration, landfill, etc. This method not only wastes precious chemical resources, but also leads to an increase in the cost of three wastes treatment, while also bringing about problems such as energy consumption and environmental pollution.

[0004] In response to the above problems, there are currently no public technical documents or patent reports that can effectively recover 2VP from these wastewaters and waste residues. The existing process treats wastewater and waste residue as three wastes, resulting in the following problems: serious waste of resources, a considerable proportion of 2VP is contained in wastewater and waste residue, but it is not effectively recovered and is directly treated as industrial waste. High treatment costs: Incineration and landfilling as traditional waste treatment methods require additional equipment investment and operating costs, and pose a greater potential threat to the environment; and they cannot meet the modern industry's demand for green, low-carbon, and environmentally friendly, limiting the company's ability to sustain sustainable development.

[0005] In summary, there is currently a lack of effective recycling technology for wastewater and waste residue in 2VP production, so a method for recovering products from 2-vinylpyridine production wastewater and waste residue is proposed to solve the above problems. Summary of the invention

[0006] The technical problem to be solved by the present invention is to overcome the existing defects and provide a method for recovering products from waste water and waste residues in the production of 2-vinylpyridine. Through distillation separation and phase separation treatment, 2-vinylpyridine in waste water and waste residues can be efficiently recovered, thereby avoiding the problem of waste of resources, reducing the demand for raw materials, and reducing the treatment cost of waste water and waste residues, thereby effectively solving the problems in the background technology.

[0007] To achieve the above object, the present invention provides the following technical solution: a method for recovering products from waste water and waste residues in the production of 2-vinylpyridine, comprising the following steps:

[0008] Step a, dissolving waste residue with waste water: mixing waste water and waste residue in a ratio of 10 to 1:1 to meet the requirements of different production process conditions, stirring until the waste residue is dissolved to form a mixed material;

[0009] Step b, adding polymerization inhibitor: adding polymerization inhibitor to the mixed material, the addition amount of polymerization inhibitor is 0-1.0% of the total mass of the mixed material, and the addition amount of polymerization inhibitor is preferably 0.5% of the total mass of the mixed material, and stirring evenly;

[0010] Step c, primary distillation: feeding the mixed material into a distillation tower, the operating temperature of the distillation tower is controlled at 100° C. to 115° C., and collecting the fractions of the primary distillation;

[0011] Step d, fraction phase separation treatment: adding potassium carbonate to the fraction obtained from the primary distillation for phase separation treatment, and obtaining an oil phase and a water phase after standing;

[0012] The oil phase is rich in 2-vinylpyridine, and the water phase contains a small amount of 2-vinylpyridine and other impurities;

[0013] Step e, re-distilling the oil phase: sending the separated oil phase into a distillation tower for re-distillation to obtain a 2-vinylpyridine product;

[0014] Step f. In step d, the separated aqueous phase is mixed with the next batch of wastewater and waste residue, and then subjected to primary distillation treatment again to achieve resource recycling.

[0015] Through the implementation of the above steps, firstly, the waste water and the waste residue are dissolved to form a uniform mixed material, and the free radical polymerization reaction is effectively inhibited by adding an inhibitor to ensure the stability of the monomer during the separation process; through the primary distillation and phase separation treatment, the target product in the oil phase and part of the organic matter in the water phase are respectively recovered, and finally a 2-vinylpyridine product with high purity is obtained through secondary distillation separation; in step f, the water phase after phase separation is recycled to further improve the resource utilization rate, reduce waste discharge, and at the same time reduce the production cost and pollution to the environment, which meets the green and environmentally friendly production requirements.

[0016] Furthermore, the ratio of wastewater to waste residue is preferably 2:1. This preferred ratio reduces the amount of wastewater used, improves resource utilization efficiency, and reduces production costs and the burden of wastewater treatment.

[0017] Furthermore, the operating temperature of the primary distillation is preferably 115°C.

[0018] Furthermore, the reflux ratio of the initial distillation is 5 to 0.5:1, preferably 3:1. The top reflux ratio is set to 3:1 by a reflux ratio controller, that is, for every fraction collected, 3 portions of distillate are condensed and returned to the tower. The appropriate reflux ratio not only improves the distillation efficiency, but also reduces the residence time of the material in the tower, avoids the degradation of the target product at high temperature, and reduces energy consumption.

[0019] Furthermore, potassium carbonate is added to the primary distillation fraction for phase separation, and the amount of potassium carbonate added is 0-20% of the fraction mass, preferably 10%.

[0020] Furthermore, in step 2, the oil phase after phase separation treatment is distilled again at a distillation temperature of 60 to 90°C, a pressure of -50 to -98 kPa, and a reflux ratio of 1 to 5:1 to obtain a product with a content greater than 99%. The operation is carried out under low temperature and negative pressure conditions, which reduces the risk of thermal decomposition, improves product purity, and at the same time reduces energy consumption and improves economy.

[0021] Furthermore, both the first distillation and the second distillation adopt total reflux, that is, the top distillate is completely condensed and returned to the tower without collecting the fraction, which is used to optimize the separation effect, test the operating parameters or improve the separation efficiency in the tower.

[0022] Furthermore, the residual 2-vinylpyridine content of the aqueous phase after phase separation is detected online. If the residual content is less than 0.1%, it can be directly discharged. Otherwise, it is mixed with the next batch of wastewater and waste residue and recycled. Through the implementation of this process, organic pollution to the environment is effectively reduced, which meets the requirements of green production and environmental protection regulations.

[0023] Furthermore, the inhibitor used is a high-temperature inhibitor, which refers to a chemical substance that can inhibit the free radical polymerization reaction of monomers (such as 2-vinylpyridine) under high temperature conditions (such as 100°C to 115°C), thereby improving separation efficiency and product quality; commonly used high-temperature inhibitors such as quinone compounds, nitro compounds, amine compounds, composite inhibitors, etc., are usually added in an amount of 0.1%-1% of the total mass of the material, preferably 0.5%, which can effectively inhibit the polymerization of the target object.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. The present invention can efficiently recover 2-vinylpyridine in wastewater and waste residue through processes such as wastewater dissolution, distillation, and phase separation treatment, thereby maximizing the reuse of resources and achieving the purpose of reducing resource recovery costs: Through this method, 2-vinylpyridine in wastewater and waste residue can be effectively recovered, resources can be reused, the cost of three wastes treatment can be significantly reduced, and environmental pollution can be reduced.

[0026] 2. The recycling method of the present invention has simple process, convenient operation and is easy to realize industrial production; the method not only has strong industrial application value, but also can bring significant economic benefits.

[0027] 3. Through phase separation and secondary distillation technology, 2-vinylpyridine products with a purity of ≥99% can be obtained to meet the needs of downstream applications for high-quality raw materials; through the recycling design of mixing the water phase with the next batch of wastewater and waste residues and then distilling again, the wastewater discharge is further reduced and the overall resource utilization efficiency is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the process flow of the present invention. DETAILED DESCRIPTION

[0029] The present invention is further described below in conjunction with examples. It should be understood that the examples described herein are only used to explain the present invention and are not used to limit the present invention.

[0030] Example 1

[0031] 1000 g of waste liquid containing 2-vinyl pyridine was mixed with 1000 g of waste residue, 0.5% of high-temperature inhibitor was added, and heating and distillation were carried out under normal pressure; when the temperature reached 115°C and the material was boiling, total reflux was timed for 1 hour, and then it was extracted with a reflux ratio of 3:1; when there was no obvious stratification in the distillate, the extraction was stopped, and a total of 125.9 g of liquid was extracted, 12.6 g of potassium carbonate was added, and after standing and stratification, the upper oil phase was taken out to obtain 35.6 g of sample, in which the 2-vinyl pyridine content was 85%, and the 2-vinyl pyridine content in the bottom material was 0.5%; finally, the oil phase product was distilled again to obtain 2-vinyl pyridine with a content of ≥99.0%.

[0032] Example 2

[0033] 1000 g of waste liquid containing 2-vinylpyridine was mixed with 500 g of waste residue, 0.5% of high-temperature inhibitor was added, and heated and distilled under normal pressure; when the temperature reached 115°C and the material was boiling, total reflux was timed for 1 hour, and then it was extracted with a reflux ratio of 3:1; when there was no obvious stratification in the distillate, the extraction was stopped, and a total of 158.0 g of liquid was extracted, 15.8 g of potassium carbonate was added, and after standing and stratification, the upper oil phase was taken out to obtain 39.7 g of sample, in which the 2-vinylpyridine content was 84%, and 2-vinylpyridine was not detected in the bottom material; finally, the oil phase product was distilled again to obtain 2-vinylpyridine with a content of ≥99.0%.

[0034] And Example 3

[0035] 1000 g of waste liquid containing 2-vinylpyridine is mixed with 500 g of waste residue, and heated and distilled under normal pressure; when the temperature reaches 115°C and the material boils, the whole reflux is timed for 1 hour, and then it is extracted with a reflux ratio of 3:1; when no organic matter is extracted from the distillate, the extraction is stopped, and a total of 128.0 g of liquid is extracted, 12.8 g of potassium carbonate is added, and after standing and stratification, the upper oil phase is taken out to obtain 35.7 g of sample, in which the 2-vinylpyridine content is 86%, and the 2-vinylpyridine content in the bottom material is 0.05%; finally, the oil phase product is distilled again to obtain 2-vinylpyridine with a content of ≥99.0%.

[0036] Example 4

[0037] 1000 g of waste liquid containing 2-vinyl pyridine was mixed with 500 g of waste residue, 0.5% of high-temperature inhibitor was added, and heating and distillation were carried out under normal pressure; when the temperature reached 115°C and the material was boiling, total reflux was timed for 1 hour, and then it was extracted with a reflux ratio of 0.5:1; when no organic matter was extracted from the distillate, the extraction was stopped, and a total of 159.0 g of liquid was extracted, 15.9 g of potassium carbonate was added, and after standing and stratification, the upper oil phase was taken out to obtain 29.0 g of sample, in which the 2-vinyl pyridine content was 81%, and the 2-vinyl pyridine content in the bottom material was 0.4%; finally, the oil phase product was distilled again to obtain 2-vinyl pyridine with a content of ≥99.0%.

[0038] Example 5

[0039] 1000 g of waste liquid containing 2-vinyl pyridine was mixed with 500 g of waste residue, 0.5% of high-temperature inhibitor was added, and heating and distillation were carried out under normal pressure; when the temperature reached 115°C and the material was boiling, total reflux was timed for 1 hour, and then it was extracted with a reflux ratio of 3:1; when no organic matter was extracted from the distillate, the extraction was stopped, and a total of 160.0 g of liquid was extracted. After standing and stratification, the upper oil phase was taken out to obtain 35.5 g of sample, in which the 2-vinyl pyridine content was 65%, and 2-vinyl pyridine was not detected in the bottom material; finally, the oil phase product was distilled again to obtain 2-vinyl pyridine with a content of ≥99.0%.

[0040] The basic principles, main features and advantages of the present invention are shown and described above. Without departing from the spirit and scope of the present invention, the present invention may also be subject to various changes and improvements, which all fall within the scope of the present invention to be protected.

Claims

1. A method for recovering products from wastewater and waste residues in the production of 2-vinylpyridine, characterized in that: The following steps are involved: Step a, dissolving waste residue with waste water: mixing waste water and waste residue in a ratio of 10 to 1:1, stirring until the waste residue is dissolved to form a mixed material; Step b, adding polymerization inhibitor: adding polymerization inhibitor to the mixed material, the added amount is 0-1.0% of the total mass of the mixed material, and stirring evenly; Step c, primary distillation: feeding the mixed material into a distillation tower, the operating temperature of the distillation tower is controlled at 100° C. to 115° C., and collecting the fractions of the primary distillation; Step d, fraction phase separation treatment: adding potassium carbonate to the fraction obtained from the primary distillation for phase separation treatment, and obtaining an oil phase and a water phase after standing; Step e, re-distilling the oil phase: sending the separated oil phase into a distillation tower for re-distillation to obtain a 2-vinylpyridine product; Step f. In step d, the separated aqueous phase is mixed with the next batch of wastewater and waste residue, and then subjected to primary distillation treatment again to achieve resource recycling.

2. A method for recovering products from 2-vinylpyridine production wastewater and waste residue according to claim 1, characterized in that: The ratio of wastewater to waste residue is preferably 2:

1.

3. A method for recovering products from 2-vinylpyridine production wastewater and waste residue according to claim 1, characterized in that: The amount of the polymerization inhibitor added is preferably 0.5% of the total mass of the mixed material.

4. A method for recovering products from 2-vinylpyridine production wastewater and waste residue according to claim 1, characterized in that: The operating temperature of the primary distillation is preferably 115°C.

5. A method for recovering products from 2-vinylpyridine production wastewater and waste residue according to claim 4, characterized in that: The reflux ratio of the primary distillation is 5 to 0.5:1, preferably 3:

1.

6. A method for recovering products from 2-vinylpyridine production wastewater and waste residue according to claim 1, characterized in that: Potassium carbonate is added to the primary distillation fraction for phase separation, and the amount of potassium carbonate added is 0-20% of the fraction mass, preferably 10%.

7. A method for recovering products from 2-vinylpyridine production wastewater and waste residue according to claim 1, characterized in that: In step 2, the oil phase after phase separation treatment is distilled again at a distillation temperature of 60 to 90° C., a pressure of -50 to -98 kPa, and a reflux ratio of 1 to 5:1 to obtain a product with a content greater than 99%.

8. A method for recovering products from 2-vinylpyridine production wastewater and waste residue according to claim 1, characterized in that: The aqueous phase after phase separation is tested online for its residual 2-vinylpyridine content. If the residual content is less than 0.1%, it can be directly discharged. Otherwise, it can be mixed with the next batch of wastewater and waste residue and recycled.

9. The method for recovering products from waste water and waste residues in the production of 2-vinylpyridine according to claim 3, wherein the polymerization inhibitor is a high-temperature polymerization inhibitor.

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