Purification device of 2, 3, 5, 6-tetrachloropyridine

Abstract

The utility model discloses a purification device of 2, 3, 5, 6-tetrachloropyridine. Comprising a crude product storage tank, a first-stage storage tank, a liquid alkali storage tank, a first-stage rectifying tower, a neutralizing tank, an extraction layering tank, a second-stage rectifying tower, a third-stage rectifying tower, a waste storage tank, a triple-effect evaporation device, a crude salt storage tank, a low-boiling-point mixture receiver, a finished product storage tank, a reboiler, a first condenser, a second condenser and a third condenser. The crude product storage tank is connected with an inlet of the first-stage storage tank through a pipeline, the side surface of the first-stage storage tank is connected with an inlet of the first-stage rectifying tower through a pipeline, and a bottom outlet of the first-stage storage tank is connected with an inlet of the reboiler through a pipeline; according to the utility model, multiple functions of mixing, extracting and rectifying are combined, high-purity 2, 3, 5, 6-tetrachloropyridine can be produced so as to meet the purity requirement of downstream products on 2, 3, 5, 6-tetrachloropyridine, and meanwhile, high-concentration salt-containing wastewater generated in the extraction process is subjected to triple-effect evaporation to obtain industrial salt for use.

Description

Technical Field

[0001] This utility model relates to the field of chemical machinery technology, specifically to a purification device for 2,3,5,6-tetrachloropyridine. Background Technology

[0002] 2,3,5,6-Tetrachloropyridine, as an important pesticide intermediate, is a crucial raw material for the synthesis of sodium trichloropyridinol, which plays a direct role in the synthesis of herbicides such as chlorpyrifos and glyphosate. 2,3,5,6-Tetrachloropyridine is primarily prepared through the selective chlorination of small chloropyridines via a catalyst. However, the resulting 2,3,5,6-tetrachloropyridine contains a large amount of acidic waste, chloropyridine, and other impurities, making it difficult to meet the purity requirements of downstream products. Therefore, developing a 2,3,5,6-tetrachloropyridine purification device is of paramount importance. Utility Model Content

[0003] The purpose of this invention is to provide a purification device for 2,3,5,6-tetrachloropyridine, in order to solve the problem mentioned in the background art that the existing preparation process produces 2,3,5,6-tetrachloropyridine containing a large amount of acidic waste, chloropyridine and other impurities, and its purity is difficult to meet the requirements of downstream products.

[0004] To achieve the above objectives, this utility model provides the following technical solution: a purification device for 2,3,5,6-tetrachloropyridine, comprising a crude product storage tank, a primary storage tank, a liquid alkali storage tank, a primary distillation column, a neutralization tank, an extraction and separation tank, a secondary distillation column, a tertiary distillation column, a waste storage tank, a triple-effect evaporator, a crude salt storage tank, a low-boiling mixture receiver, a finished product storage tank, a reboiler, a first condenser, a second condenser, and a third condenser;

[0005] The crude product storage tank is connected to the inlet of the primary storage tank via a pipeline. The side of the primary storage tank is connected to the inlet of the primary distillation column via a pipeline. The bottom outlet of the primary storage tank is connected to the inlet of the reboiler via a pipeline. The outlet of the reboiler is connected to the inlet of the waste storage tank via a pipeline. The outlets of the liquid alkali storage tank and the primary distillation column are respectively connected to the inlet of the neutralization tank via pipelines. The outlet of the neutralization tank is connected to the side inlet of the extraction layer tank via a pipeline. The side outlet of the extraction layer tank is connected to the inlet of the secondary distillation column via a pipeline.

[0006] The outlet at the bottom of the secondary distillation column is connected to the inlet of the No. 1 condenser via a pipe. The outlet of the No. 1 condenser is connected to the triple-effect evaporator via a pipe. The bottom outlet of the triple-effect evaporator is connected to the inlet of the crude salt storage tank via a pipe. The side outlet of the secondary distillation column is connected to the inlet of the tertiary distillation column via a pipe. The top outlet of the secondary distillation column is connected to the inlet of the No. 2 condenser via a pipe. The outlet of the No. 2 condenser is connected to the inlet of the low-boiling mixture receiver via a pipe. The top outlet of the tertiary distillation column is connected to the inlet of the No. 3 condenser via a pipe. The outlet of the No. 3 condenser is connected to the inlet of the finished product storage tank via a pipe.

[0007] Preferably, the crude product storage tank, primary storage tank, liquid alkali storage tank, primary distillation column, secondary distillation column, tertiary distillation column and neutralization tank are all equipped with external level gauges and side sight glasses.

[0008] Preferably, the neutralization tank is provided with a baffle inside.

[0009] Compared with the prior art, the beneficial effects of this utility model are as follows: This 2,3,5,6-tetrachloropyridine purification device combines multiple functions such as mixing, extraction, and distillation, and can produce high-purity 2,3,5,6-tetrachloropyridine to meet the purity requirements of downstream products. Simultaneously, the high-concentration saline wastewater generated during the extraction process is utilized by triple-effect evaporation to obtain industrial salt; the primary distillation produces crude 2,3,5,6-tetrachloropyridine, which facilitates continuous processing of 2,3,5,6-tetrachloropyridine; the low-boiling-point mixture obtained from the secondary distillation can be returned to the chlorination workshop for further chlorination; and the tertiary distillation yields high-purity 2,3,5,6-tetrachloropyridine.

[0010] This 2,3,5,6-tetrachloropyridine purification device maximizes the utilization of 2,3,5,6-tetrachloropyridine raw material through a three-stage distillation process. It not only saves economic costs but also conforms to the concept of green chemistry. It is highly practical and can well meet the needs of 2,3,5,6-tetrachloropyridine raw material purification. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the structure of this utility model.

[0012] In the diagram: 1. Crude product storage tank; 2. Primary storage tank; 3. Liquid alkali storage tank; 4. Primary distillation column; 5. Neutralization tank; 6. Extraction and separation tank; 7. Secondary distillation column; 8. Tertiary distillation column; 9. Waste storage tank; 10. Triple-effect evaporator; 11. Crude salt storage tank; 12. Low-boiling mixture receiver; 13. Finished product storage tank; 14. Reboiler; 151. No. 1 condenser; 152. No. 2 condenser; 153. No. 3 condenser. Detailed Implementation

[0013] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0014] Please see Figure 1 The present invention provides an embodiment of a purification device for 2,3,5,6-tetrachloropyridine, comprising a crude product storage tank 1, a primary storage tank 2, a liquid alkali storage tank 3, a primary distillation column 4, a neutralization tank 5, an extraction and separation tank 6, a secondary distillation column 7, a tertiary distillation column 8, a waste storage tank 9, a triple-effect evaporator 10, a crude salt storage tank 11, a low-boiling mixture receiver 12, a finished product storage tank 13, a reboiler 14, a first condenser 151, a second condenser 152, and a third condenser 153;

[0015] The crude product storage tank 1 is connected to the inlet of the primary storage tank 2 via a pipeline. The side of the primary storage tank 2 is connected to the inlet of the primary distillation column 4 via a pipeline. The bottom outlet of the primary storage tank 2 is connected to the inlet of the reboiler 14 via a pipeline. The outlet of the reboiler 14 is connected to the inlet of the waste storage tank 9 via a pipeline. The outlets of the liquid alkali storage tank 3 and the primary distillation column 4 are respectively connected to the inlet of the neutralization tank 5 via pipelines. The neutralization tank 5 is equipped with a baffle and has an oil-water separation function. The outlet of the neutralization tank 5 is connected to the side inlet of the extraction layer tank 6 via a pipeline. The side outlet of the extraction layer tank 6 is connected to the inlet of the secondary distillation column 7 via a pipeline.

[0016] The outlet at the bottom of the secondary distillation column 7 is connected to the inlet of the No. 1 condenser 151 via a pipe. The outlet of the No. 1 condenser 151 is connected to the triple-effect evaporator 10 via a pipe. The bottom outlet of the triple-effect evaporator 10 is connected to the inlet of the crude salt storage tank 11 via a pipe. The side outlet of the secondary distillation column 7 is connected to the inlet of the tertiary distillation column 8 via a pipe. The top outlet of the secondary distillation column 7 is connected to the inlet of the No. 2 condenser 152 via a pipe. The outlet of the No. 2 condenser 152 is connected to the inlet of the low-boiling mixture receiver 12 via a pipe. The top outlet of the tertiary distillation column 8 is connected to the inlet of the No. 3 condenser 153 via a pipe. The outlet of the No. 3 condenser 153 is connected to the inlet of the finished product storage tank 13 via a pipe.

[0017] External level gauges and side sight glasses are installed on crude product storage tank 1, primary storage tank 2, liquid alkali storage tank 3, primary distillation column 4, secondary distillation column 7, tertiary distillation column 8 and neutralization tank 5 to facilitate observation of liquid levels.

[0018] The crude product storage tank 1, primary storage tank 2, liquid alkali storage tank 3, primary distillation column 4, neutralization tank 5, extraction and stratification tank 6, secondary distillation column 7, tertiary distillation column 8, waste storage tank 9, triple-effect evaporator 10, crude salt storage tank 11, low-boiling mixture receiver 12, finished product storage tank 13, reboiler 14, No. 1 condenser 151, No. 2 condenser 152, and No. 3 condenser 153 in the device are existing technologies, and their composition and structure are exactly the same as existing devices.

[0019] Working principle: First, 2,3,5,6-tetrachloropyridine raw material enters the primary distillation column 4 through the crude product storage tank 1. A large amount of crude 2,3,5,6-tetrachloropyridine is distilled off. The waste remaining at the bottom of the primary distillation column 4 is processed by the reboiler 14 and then stored in the waste storage tank 9.

[0020] The crude product undergoes a neutralization reaction with alkali from liquid alkali storage tank 3, and the neutralization product then enters extraction and separation tank 5. After extraction and settling, the aqueous phase is a high-concentration brine, which is condensed by condenser 151 and then concentrated and cooled by triple-effect evaporator 10. The resulting industrial salt enters crude salt storage tank 11 for reuse, and the remaining oil phase enters secondary distillation column 7. After secondary distillation, the light components of the resulting low-boiling-point mixture are condensed and enriched by condenser 152 and then enter low-boiling-point mixture receiver 12. The raw materials required for the synthesis of 2,3,5,6-tetrachloropyridine can be obtained by re-chlorination.

[0021] The secondary distillation product enters the tertiary distillation column 8 for tertiary distillation. The tertiary distillation product is condensed by the No. 3 condenser 153 and then enters the finished product storage tank 13, which is the purified 2,3,5,6-tetrachloropyridine.

[0022] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0023] In the description of this utility model, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "head," "tail," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. In addition, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0024] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection or a detachable connection; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

Claims

1. A purification apparatus for 2,3,5,6-tetrachloropyridine, comprising a crude product storage tank (1), a primary storage tank (2), a liquid alkali storage tank (3), a primary distillation column (4), a neutralization tank (5), an extraction and separation tank (6), a secondary distillation column (7), a tertiary distillation column (8), a waste storage tank (9), a triple-effect evaporator (10), a crude salt storage tank (11), a low-boiling mixture receiver (12), a finished product storage tank (13), a reboiler (14), a first condenser (151), a second condenser (152), and a third condenser (153), characterized in that: The crude product storage tank (1) is connected to the inlet of the primary storage tank (2) via a pipe. The side of the primary storage tank (2) is connected to the inlet of the primary distillation column (4) via a pipe. The bottom outlet of the primary storage tank (2) is connected to the inlet of the reboiler (14) via a pipe. The outlet of the reboiler (14) is connected to the inlet of the waste storage tank (9) via a pipe. The outlets of the liquid alkali storage tank (3) and the primary distillation column (4) are respectively connected to the inlet of the neutralization tank (5) via pipe. The outlet of the neutralization tank (5) is connected to the side inlet of the extraction layer tank (6) via a pipe. The side outlet of the extraction layer tank (6) is connected to the inlet of the secondary distillation column (7) via a pipe. The outlet at the bottom of the secondary distillation column (7) is connected to the inlet of the first condenser (151) via a pipe. The outlet of the first condenser (151) is connected to the triple-effect evaporator (10) via a pipe. The bottom outlet of the triple-effect evaporator (10) is connected to the inlet of the crude salt storage tank (11) via a pipe. The side outlet of the secondary distillation column (7) is connected to the inlet of the tertiary distillation column (8) via a pipe. The top outlet of the secondary distillation column (7) is connected to the inlet of the second condenser (152) via a pipe. The outlet of the second condenser (152) is connected to the inlet of the low-boiling mixture receiver (12) via a pipe. The top outlet of the tertiary distillation column (8) is connected to the inlet of the third condenser (153) via a pipe. The outlet of the third condenser (153) is connected to the inlet of the finished product storage tank (13) via a pipe.

2. A purification apparatus for 2,3,5,6-tetrachloropyridine according to claim 1, characterized in that: The crude product storage tank (1), primary storage tank (2), liquid alkali storage tank (3), primary distillation column (4), secondary distillation column (7), tertiary distillation column (8) and neutralization tank (5) are all equipped with external level gauges and side sight glasses.

3. A purification apparatus for 2,3,5,6-tetrachloropyridine according to claim 1, characterized in that: The neutralization tank (5) is equipped with a baffle inside.

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