A production system of 2-chloro-3-isothiocyanato-1-propene
By designing a 2-chloro-3-isothiocyano-1-propene production system, and utilizing the connection between layered tanks and recovery tanks, the recovery of 2,3-dichloropropene and the reuse of wastewater were realized. This solved the problems of high wastewater treatment pressure and high cost in existing systems, reduced production costs, and improved the purity of the organic phase.
Patent Information
- Application Number
- CN202522067909.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-25
- Publication Date
- 2026-08-25
- Estimated Expiration
- 2035-09-25
AI Technical Summary
The existing 2-chloro-3-isothiocyano-1-propylene production system suffers from high wastewater treatment pressure and high production costs, making it difficult to achieve wastewater reuse and resource recycling.
Design a production system that collects substances with different boiling points by connecting a stratification tank and a product collection tank to the condenser outlet, and connects a recovery tank to a substitution vessel through a pipeline to achieve the recovery of 2,3-dichloropropylene; at the same time, by connecting the aqueous phase outlet of the stratification tank to a water collection tank, a portion of the wastewater is recycled and reused, and water-soluble impurities in the organic phase are removed in a water washing vessel.
It reduced the pressure on wastewater treatment, enabled resource reuse, lowered production costs, and improved the purity of the organic phase.
Smart Images
Figure CN224672714U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of chemical intermediate production technology, specifically a production system for 2-chloro-3-isothiocyano-1-propylene. Background Technology
[0002] 2-Chloro-3-isothiocyano-1-propene is an important chemical intermediate, typically produced from 2,3-dichloropropene as a starting material through a reaction with a thiocyanate solution, followed by continuous dropwise addition, temperature control, phase separation, and distillation. 2-Chloro-3-isothiocyano-1-propene is a key intermediate in the production of pesticides such as thiamethoxam, thiamethoxam, and 2-chloro-5-chloromethylthiazole, holding a significant position in pesticide synthesis. The production of 2-chloro-3-isothiocyano-1-propene generates wastewater containing organic solvents. Traditionally, this wastewater is centrally treated, increasing production costs and the burden on wastewater treatment facilities. Therefore, there is a need to develop a production system for 2-chloro-3-isothiocyano-1-propene that can reuse the synthetic wastewater and reduce production costs. Utility Model Content
[0003] To address the above technical problems, this utility model provides a production system for 2-chloro-3-isothiocyano-1-propylene that can reuse synthetic wastewater and reduce enterprise production costs, thereby solving the problems of high wastewater treatment pressure and high production costs in existing 2-chloro-3-isothiocyano-1-propylene production systems.
[0004] To solve the above-mentioned technical problems, the present invention provides a production system for 2-chloro-3-isothiocyano-1-propylene, comprising a substitution vessel and a vacuum distillation vessel. The organic phase outlet of the substitution vessel is connected to the feed inlet of the vacuum distillation vessel via a pipe. The outlet of the vacuum distillation vessel is connected to the condenser inlet via a pipe. The condenser outlet is connected to a layering tank and a product collection tank via two pipes respectively. The organic phase outlet of the layering tank is connected to the feed inlet of a recovery tank via a pipe. The outlet of the recovery tank is connected to the feed inlet of the substitution vessel via a pipe.
[0005] Furthermore, it also includes a preparation vessel, the outlet of which is connected to the inlet of the replacement vessel via a pipe.
[0006] Furthermore, the water phase outlet of the stratification tank is connected to the inlet of the water collection tank via a pipe, and the outlet of the water collection tank is connected to the inlet of the preparation vessel via a pipe.
[0007] Furthermore, the organic phase outlet of the substitution vessel is connected to the feed inlet of the water washing vessel via a pipe, and the organic phase outlet of the water washing vessel is connected to the feed inlet of the vacuum distillation vessel via a pipe.
[0008] This utility model has the following advantages compared with the prior art:
[0009] 1. This utility model, by connecting a stratification tank and a product collection tank to the condenser outlet, can collect 2,3-dichloropropene, a water mixture, and the product 2-chloro-3-isothiocyano-1-propene separately according to their different boiling points. By connecting the organic phase outlet of the stratification tank to a recovery tank and connecting the outlet of the recovery tank to a substitution vessel via a pipeline, the recycling and reuse of 2,3-dichloropropene can be achieved. By connecting the aqueous phase outlet of the stratification tank to a water collection tank and connecting the outlet of the water collection tank to a preparation vessel via a pipeline, a portion of the wastewater can be recycled and reused. This production system can reduce wastewater treatment pressure and production costs.
[0010] 2. This utility model removes some water-soluble impurities from the organic phase after reaction by setting up a water washing tank to wash the organic phase after reaction, thereby improving the purity of the organic phase. Attached Figure Description
[0011] Figure 1 This is a schematic diagram of the structure of this utility model.
[0012] In the diagram: 1. Preparation vessel, 2. Substitution vessel, 3. Washing vessel, 4. Vacuum distillation vessel, 5. Condenser, 6. Separation tank, 7. Product collection tank, 8. Recovery tank, 9. Water collection tank. Detailed Implementation
[0013] The present invention will be further described below with reference to the accompanying drawings.
[0014] In the production of the pesticide synthesis intermediate 2-chloro-5-chloromethylthiazole, 2-chloro-3-isothiocyano-1-propene is required as an intermediate raw material. The preparation of 2-chloro-3-isothiocyano-1-propene involves a substitution reaction using sodium thiocyanate and 2,3-dichloropropene as raw materials. This process generates wastewater containing organic solvents. Traditional production systems centrally treat this wastewater at a wastewater treatment plant, increasing the company's wastewater treatment burden and production costs. Therefore, it is necessary to develop a production system that can effectively utilize the wastewater generated during the production process to reduce production costs and achieve resource recycling and reuse. For example... Figure 1The system shown is a production system for 2-chloro-3-isothiocyano-1-propene, comprising a preparation vessel 1, a substitution vessel 2, and a vacuum distillation vessel 4. The purpose of the preparation vessel 1 is to prepare a 40% sodium thiocyanate aqueous solution from 99% sodium thiocyanate. High-purity solid sodium thiocyanate is difficult to accurately feed and participate in liquid-phase reactions; preparing it as a 40% aqueous solution facilitates pumping and metering. The outlet flange at the bottom of the preparation vessel 1 is connected to a pipe that is connected to the inlet flange of the substitution vessel 2. The organic phase outlet flange of the substitution vessel 2 is connected to a pipe that is connected to water. The inlet flange of washing vessel 3 is connected to a pipeline. The purpose of washing vessel 3 is to purify the organic phase. The organic phase separated from the substitution vessel 2 may still contain a small amount of water-soluble impurities, such as trace amounts of NaSCN and NaCl. Washing with water can further remove these water-soluble impurities and purify the organic phase. The outlet flange of the organic phase of washing vessel 3 is connected to a pipeline that connects to the inlet flange of vacuum distillation vessel 4. The target product and the raw material 2,3-dichloropropene are both heat-sensitive organic compounds that are easily decomposed, polymerized, or deteriorated at high temperatures. Reduced pressure significantly lowers the boiling point of liquids, allowing materials to boil and vaporize at temperatures far below atmospheric pressure, thus avoiding high-temperature damage and ensuring product quality and yield. The first distillate is the lower-boiling-point component, mainly the unreacted raw material 2,3-dichloropropene and some entrained water. After the fore-distillate is removed, distillation continues under specific vacuum and temperature conditions to obtain the higher-boiling-point target product, 2-chloro-3-isothiocyano-1-propene. The outlet flange of the reduced-pressure distillation vessel 4 is connected to a pipe that connects to the inlet flange of the condenser 5. The outlet of the condenser 5 is connected to two pipes via a tee, the other ends of which are connected to the layering tank 6 and the product collection tank 7, respectively. The organic phase outlet flange of the layering tank 6 is connected to a pipe that connects to the inlet flange of the recovery tank 8, and the outlet flange of the recovery tank 8 is connected to the inlet flange of the substitution vessel 2. The aqueous phase outlet flange of the layering tank 6 is connected to a pipe that connects to the inlet flange of the water collection tank 9, and the outlet flange of the water collection tank 9 is connected to the inlet flange of the preparation vessel 1.
[0015] To facilitate the control of material transport between each process and ensure smooth transport between processes during the reaction, valves and transfer pumps are connected to the pipeline between preparation vessel 1 and substitution vessel 2; valves and transfer pumps are connected to the pipeline between substitution vessel 2 and washing vessel 3; valves and transfer pumps are connected to the pipeline between washing vessel 3 and vacuum distillation vessel 4; valves are connected to the pipeline between vacuum distillation vessel 4 and condenser 5; valves and transfer pumps are connected to the pipeline between layering tank 6 and recovery tank 8; valves and transfer pumps are connected to the pipeline between layering tank 6 and water collection tank 9; valves and transfer pumps are connected to the pipeline between recovery tank 8 and substitution vessel 2; and valves and transfer pumps are connected to the pipeline between water collection tank 9 and preparation vessel 1.
[0016] In this embodiment, the preparation vessel 1, substitution vessel 2, water washing vessel 3, vacuum distillation vessel 4, condenser 5, layering tank 6, product collection tank 7, recovery tank 8, and water collection tank 9 are all existing reaction vessels, which are conventional equipment in the chemical production process. The innovation of this application lies in connecting the above equipment to form a new production system.
[0017] The working principle of this embodiment is as follows:
[0018] In the production of 2-chloro-3-isothiocyano-1-propene, 99% sodium thiocyanate and water are added to preparation vessel 1 to prepare a 40% sodium thiocyanate solution. This 40% sodium thiocyanate solution is then added to substitution vessel 2. When the reaction temperature is controlled at 70–75°C, 2,3-dichloropropene is added dropwise to initiate the substitution reaction. The addition is completed in 2.5–3 hours. The reaction pressure is atmospheric pressure, and the reaction temperature is controlled at 90–95°C. After maintaining this temperature for 5–5.5 hours, samples are taken for analysis. The reaction ends when the 2,3-dichloropropene content in substitution vessel 2 is ≤0.5%. Water is then added to lower the temperature of the material inside the vessel to 65–70°C. Stop stirring, allow to stand and separate into layers, transfer the organic phase to water washing vessel 3 for washing, then allow to stand and separate into layers again, transfer the organic phase to vacuum distillation vessel 4 for vacuum distillation, the fore fraction 2,3-dichloropropene and water mixture first passes through condenser 5 and enters separation tank 6, the latter fraction 2-chloro-3-isothiocyano-1-propene passes through condenser 5 and enters product collection tank 7; after standing and separating into layers, the 2,3-dichloropropene in separation tank 6 enters recovery tank 8, and the aqueous phase enters water collection tank 9, the 2,3-dichloropropene in recovery tank 8 is reused in substitution vessel 2, and the water in water collection tank 9 is reused in preparation vessel 1.
Claims
1. A production system for 2-chloro-3-isothiocyano-1-propylene, comprising a substitution vessel (2) and a vacuum distillation vessel (4), wherein the organic phase outlet of the substitution vessel (2) is connected to the feed inlet of the vacuum distillation vessel (4) via a pipe, and the outlet of the vacuum distillation vessel (4) is connected to the inlet of a condenser (5) via a pipe, characterized in that: The outlet of the condenser (5) is connected to the stratification tank (6) and the product collection tank (7) through two pipes respectively. The organic phase outlet of the stratification tank (6) is connected to the feed inlet of the recovery tank (8) through a pipe. The outlet of the recovery tank (8) is connected to the feed inlet of the substitution vessel (2) through a pipe.
2. The production system for 2-chloro-3-isothiocyano-1-propene according to claim 1, characterized in that: It also includes a preparation vessel (1), the outlet of which is connected to the inlet of the replacement vessel (2) via a pipe.
3. The production system for 2-chloro-3-isothiocyano-1-propene according to claim 2, characterized in that: The water phase outlet of the layered tank (6) is connected to the inlet of the water collection tank (9) via a pipe, and the outlet of the water collection tank (9) is connected to the inlet of the preparation vessel (1) via a pipe.
4. The production system for 2-chloro-3-isothiocyano-1-propylene according to claim 3, characterized in that: The organic phase outlet of the substitution vessel (2) is connected to the feed inlet of the washing vessel (3) via a pipe, and the organic phase outlet of the washing vessel (3) is connected to the feed inlet of the vacuum distillation vessel (4) via a pipe.