A method for synthesizing 1,1,1,3-tetrachloropropane

Abstract

This invention discloses a method for synthesizing 1,1,1,3-tetrachloropropane, belonging to the field of fine chemical intermediate synthesis technology. The method uses chloroform, chlorine, and ethylene as raw materials. Chloroform is mixed with a specific solid chloride catalyst as a mother liquor and added to a reactor. Chlorine and ethylene are continuously introduced from the bottom of the reactor. An addition reaction occurs under reaction conditions of 80-120℃ and 0.5-1.5 MPa, wherein the molar ratio of chloroform, chlorine, and ethylene is controlled at 1.6:0.8:1. The crude product generated is separated by distillation in a recovery tower, and unreacted chloroform and ethylene are returned to the reactor for recycling. No wastewater is generated throughout the reaction process. This invention features a simple process, high reaction selectivity, high catalyst activity and reusability, significantly improved raw material utilization, low equipment material requirements, low investment, and easy implementation for continuous industrial production. It overcomes the technical shortcomings of existing technologies, such as numerous by-products, complex control, large catalyst consumption, and difficult wastewater treatment.

Description

Technical Field

[0001] This invention relates to the field of fine chemical intermediate synthesis technology, specifically to a method for synthesizing 1,1,1,3-tetrachloropropane. Background Technology

[0002] 1,1,1,3-Tetrachloropropane is a key intermediate in the synthesis of various fine chemical products. It can be used to prepare environmentally friendly refrigerants and chlorinated organic compounds such as 1,1,1,2,3-pentachloropropane, playing an important role in refrigeration, chemical synthesis, and other fields. It also has good solubility and can be used as an industrial solvent to dissolve oils, resins, and other substances. In organic synthesis, it can also be used as an extractant to separate and purify target products. At the same time, it is an important raw material for pesticide synthesis and can be used to produce various insecticides, herbicides, and other pesticide products, contributing to the prevention and control of agricultural pests and diseases.

[0003] Several methods for preparing 1,1,1,3-tetrachloropropane have been disclosed in the prior art, such as the method for continuous production of 1,1,1,3-tetrachloropropane in patent number CN120205036A, a method for preparing 1,1,1,3-tetrachloropropane in patent number CN202110143120.7, and a method for preparing 1,1,1,3-tetrachloropropane in patent number 202010337171.9. However, these prior art methods all have many technical defects: the reaction process produces a variety of by-products, resulting in difficulty in product separation and low purity; the process control conditions are complex, requiring high standards for equipment and operators, and prone to reaction instability; the catalyst consumption is large, and the catalyst has low activity and cannot be reused, significantly increasing the cost of raw materials; the reaction process generates a large amount of industrial wastewater, which has a complex composition, is difficult to treat, and is costly. Direct discharge of this wastewater would cause serious environmental pollution and does not meet the requirements of current environmentally friendly production. Therefore, developing a simple, catalyst-stable, efficient, safe, and environmentally friendly method for preparing 1,1,1,3-tetrachloropropane has become an urgent technical problem to be solved in this field. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for synthesizing 1,1,1,3-tetrachloropropane. This method has a simple process, high reaction selectivity, high catalyst activity and reusability, high raw material utilization, low equipment material requirements and low investment, and is easy to achieve continuous industrial production. Moreover, no wastewater is generated during the entire reaction process, which solves the problems of many by-products, complex control, large catalyst consumption and difficult wastewater treatment in the prior art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for synthesizing 1,1,1,3-tetrachloropropane, using chloroform and chlorine gas (… Using chloroform and ethylene as reactants, and at least one of cyclic iron, ferrous chloride, ferric chloride, aluminum chloride, magnesium chloride, tributyl phosphate, triethyl phosphate, and triethyl phosphite as a solid chloride catalyst, chloroform is thoroughly mixed with the solid chloride catalyst to form a reaction mother liquor, which is then added to a reaction vessel reactor. Chlorine and ethylene are continuously introduced from the bottom of the reaction vessel reactor, causing the reactants to undergo an addition reaction to produce 1,1,1,3-tetrachloropropane. No wastewater is generated during the entire reaction process. After the reaction, the crude 1,1,1,3-tetrachloropropane product is sent to a recovery tower for distillation and separation. The unreacted chloroform and ethylene separated by the recovery tower are directly returned to the reaction vessel reactor for recycling, while the unreacted catalyst remains in the reactor and can participate in the next addition reaction.

[0006] Furthermore, the reaction temperature of the addition reaction is strictly controlled at 80-120℃. During the reaction, the temperature is maintained within this range by the reactor temperature control system to avoid the problem of additional by-products being generated due to excessively high temperature and the reaction rate decreasing due to excessively low temperature. Moreover, the reaction conversion rate of the raw materials and the selectivity of the products can reach the optimal level within this temperature range.

[0007] Furthermore, the reaction pressure of the addition reaction is strictly controlled at 0.5-1.5 MPa. The pressure inside the reactor is maintained by atmospheric pressure boosting. This pressure range can ensure that chlorine and ethylene are fully dissolved in the mother liquor and react with chloroform, while avoiding the problems of increased equipment sealing requirements, increased production safety risks, and excessive equipment investment costs caused by high pressure.

[0008] Furthermore, the chloroform and chlorine gas ( The feed molar ratio of chloroform to ethylene is strictly controlled at 1.6:0.8:1. During the reaction, raw materials are continuously added according to this molar ratio to ensure that chloroform is slightly in excess to fully consume chlorine and ethylene, reduce the generation of by-products caused by the imbalance of raw material ratio, and at the same time, excess chloroform can be recycled after separation in the subsequent recovery tower, effectively improving the overall utilization rate of raw materials.

[0009] Furthermore, the solid chloride catalyst is one or more of cyclic iron, ferrous chloride, ferric chloride, aluminum chloride, magnesium chloride, tributyl phosphate, triethyl phosphate, and triethyl phosphite, used in combination. When the catalyst is mixed with chloroform to form a reaction mother liquor, it is uniformly dispersed in the chloroform. The amount of catalyst added is 0.5%-5% of the mass of chloroform. This catalyst has high activity and strong selectivity, and good stability under reaction conditions of 80-120℃ and 0.5-1.5MPa. There is no catalyst loss after the reaction is completed, and it can be directly retained in the reactor to participate in the addition reaction again without additional separation and replenishment.

[0010] Furthermore, the reactor is a dedicated reaction vessel reactor, which is equipped with a temperature control system, a pressure control system, a raw material feeding system, and a gas distributor. Chlorine and ethylene are uniformly introduced into the reaction mother liquor through the gas distributor at the bottom of the reactor, so that the gaseous raw materials can fully contact the chloroform and catalyst in the liquid phase, thereby improving the mass transfer efficiency of the reaction and ensuring that the addition reaction proceeds uniformly and continuously. The reactor is made of ordinary chemical carbon steel, without the need for special corrosion-resistant and high-pressure materials, resulting in low equipment investment costs.

[0011] Furthermore, the main reaction formula for the addition reaction is: → The reaction process generates only 1,1,1,3-tetrachloropropane and hydrogen chloride, with no other organic byproducts. The hydrogen chloride is discharged from the top of the reactor in gaseous form and can be collected and treated later. The entire reaction process generates no wastewater or waste residue, meeting the requirements for safe and environmentally friendly production.

[0012] Furthermore, the crude product is separated by distillation using a recovery tower system combining a low-boiling tower and a high-boiling tower. The crude product first enters the low-boiling tower, where unreacted chloroform and ethylene mixed gas is distilled off at the top. After condensation and liquefaction, this gas is directly fed back to the feed end of the reaction vessel reactor for recycling. The material at the bottom of the low-boiling tower enters the high-boiling tower, where high-purity 1,1,1,3-tetrachloropropane is distilled off at the top. No residue is generated at the bottom of the high-boiling tower, and the yield of the distillation separation process reaches over 98%.

[0013] Furthermore, the synthesis method is a continuous production process. After the mother liquor of chloroform and catalyst is added to the reactor at once, chlorine and ethylene are continuously introduced from the bottom. The crude product is continuously discharged from the reactor outlet to the recovery tower. The recovered unreacted raw materials are continuously returned to the reactor. The entire production process does not need to be interrupted. The reaction rate is fast and the yield of 1,1,1,3-tetrachloropropane per unit time is high. The production efficiency is more than 50% higher than that of the existing batch process.

[0014] Furthermore, the operation steps of the synthesis method are as follows: (1) Preparation of reaction mother liquor: A certain amount of chloroform is added to the reaction vessel reactor, and a solid chloride catalyst is added at 0.5% to 5% of the mass of chloroform. The mixture is stirred to make the catalyst evenly dispersed to form the reaction mother liquor. (2) Reaction condition adjustment: The temperature inside the reactor is raised to 80-120℃ by the temperature control system, and the pressure inside the reactor is adjusted to 0.5-1.5MPa and kept stable by the pressure control system; (3) Continuous feed of raw materials: Chlorine and ethylene are continuously fed into the mother liquor from the bottom of the reactor through a gas distributor at a molar ratio of 1.6:0.8:1, so that the three reactants can undergo an addition reaction. (4) Crude product discharge: The crude product 1,1,1,3-tetrachloropropane generated in the reaction is continuously discharged from the outlet of the reactor; (5) Crude product separation: The crude product is distilled and separated by a recovery tower system consisting of a low-boiling tower and a high-boiling tower to obtain high-purity 1,1,1,3-tetrachloropropane product. Unreacted chloroform and ethylene are recycled, and the catalyst is stored in the reactor for reuse.

[0015] This invention provides a method for synthesizing 1,1,1,3-tetrachloropropane, which has the following beneficial effects: 1. Preparation of reaction mother liquor: Add a measured amount of chloroform to the reaction vessel reactor, and add a solid chloride catalyst at 0.5%-5% of the mass of chloroform. Stir to make the catalyst evenly dispersed to form the reaction mother liquor; 2. Reaction condition adjustment: The temperature inside the reactor is raised to 80-120℃ by the temperature control system, and the pressure inside the reactor is adjusted to 0.5-1.5MPa and maintained stable by the pressure control system; 3. Continuous feed of raw materials: Chlorine and ethylene are continuously fed into the mother liquor from the bottom of the reactor through a gas distributor at a molar ratio of 1.6:0.8:1, so that the three reactants can undergo an addition reaction. 4. Crude product discharge: The crude 1,1,1,3-tetrachloropropane product generated in the reaction is continuously discharged from the outlet of the reactor; 6. Crude product separation: The crude product is separated by distillation in a recovery tower system consisting of a low-boiling tower and a high-boiling tower. Unreacted chloroform and ethylene are distilled off the top of the low-boiling tower and returned to the reactor for recycling after condensation. High-purity 1,1,1,3-tetrachloropropane is distilled off the top of the high-boiling tower. The distillation separation yield is over 98%. Attached Figure Description

[0016] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0017] Figure 1 This is a flowchart illustrating the preparation of the reaction mother liquor in this invention. Figure 2 This is a flowchart illustrating the reaction process control of the present invention. Figure 3 This is a flowchart illustrating the crude product separation and recycling process of the present invention. Figure 4 This is a flowchart of the process for this invention. Detailed Implementation

[0018] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses consistent with some aspects of this disclosure as detailed in the appended claims.

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0020] Example 1

[0021] A method for synthesizing 1,1,1,3-tetrachloropropane, comprising the following steps: Preparation of reaction mother liquor: 16 mol of chloroform was added to a carbon steel reaction vessel reactor, and 1% by mass of ferrous chloride catalyst of chloroform was added. The mixture was stirred to uniformly disperse the ferrous chloride to form the reaction mother liquor. Reaction condition adjustment: The temperature inside the reactor is raised to 80℃ by the temperature control system, and the pressure inside the reactor is adjusted to 0.5MPa and maintained stable by the pressure control system; Continuous feed of raw materials: 8 mol of chlorine gas and 10 mol of ethylene are continuously fed into the mother liquor from the gas distributor at the bottom of the reactor at a molar ratio of 1.6:0.8:1 to carry out the addition reaction. Crude product discharge: The crude product 1,1,1,3-tetrachloropropane generated in the reaction is continuously discharged from the outlet of the reactor; Crude product separation: The crude product is separated by distillation in a recovery tower consisting of a low-boiling tower and a high-boiling tower. Unreacted chloroform and ethylene are distilled off the top of the low-boiling tower and returned to the reactor for recycling after condensation. 1,1,1,3-tetrachloropropane is distilled off the top of the high-boiling tower. The distillation separation yield is 98.2%.

[0022] No wastewater is generated during the entire reaction process. Hydrogen chloride gas is discharged and collected from the top of the reactor. The ferrous chloride catalyst is retained in the reactor and can directly participate in the next reaction. The purity of the product 1,1,1,3-tetrachloropropane reaches 99.5%.

[0023] Example 2

[0024] A method for synthesizing 1,1,1,3-tetrachloropropane, comprising the following steps: Preparation of reaction mother liquor: 16 mol of chloroform was added to a carbon steel reaction vessel reactor, and 3% by mass of aluminum chloride and tributyl phosphate composite catalyst (mass ratio 1:1) was added. The mixture was stirred to disperse the catalyst evenly and form the reaction mother liquor. Reaction condition adjustment: The temperature inside the reactor is raised to 100℃ by the temperature control system, and the pressure inside the reactor is adjusted to 1.0MPa and maintained stable by the pressure control system; Continuous feed of raw materials: 8 mol of chlorine gas and 10 mol of ethylene are continuously fed into the mother liquor from the gas distributor at the bottom of the reactor at a molar ratio of 1.6:0.8:1 to carry out the addition reaction. Crude product discharge: The crude product 1,1,1,3-tetrachloropropane generated in the reaction is continuously discharged from the outlet of the reactor; Crude product separation: The crude product is separated by distillation in a recovery tower consisting of a low-boiling tower and a high-boiling tower. Unreacted chloroform and ethylene are distilled off the top of the low-boiling tower and returned to the reactor for recycling after condensation. 1,1,1,3-tetrachloropropane is distilled off the top of the high-boiling tower. The distillation separation yield is 98.8%.

[0025] No wastewater is generated during the entire reaction process. Hydrogen chloride gas is discharged and collected from the top of the reactor. The compound catalyst is stored in the reactor and can directly participate in the next reaction. The purity of the product 1,1,1,3-tetrachloropropane reaches 99.7%.

[0026] Example 3

[0027] A method for synthesizing 1,1,1,3-tetrachloropropane, comprising the following steps: Preparation of reaction mother liquor: 16 mol of chloroform was added to a carbon steel reaction vessel reactor, and 5% of the mass of chloroform was added to a cyclic iron catalyst. The mixture was stirred to uniformly disperse the cyclic iron and form a reaction mother liquor. Reaction condition adjustment: The temperature inside the reactor is raised to 120℃ by the temperature control system, and the pressure inside the reactor is adjusted to 1.5MPa and maintained stable by the pressure control system; Continuous feed of raw materials: 8 mol of chlorine gas and 10 mol of ethylene are continuously fed into the mother liquor from the gas distributor at the bottom of the reactor at a molar ratio of 1.6:0.8:1 to carry out the addition reaction. Crude product discharge: The crude product 1,1,1,3-tetrachloropropane generated in the reaction is continuously discharged from the outlet of the reactor; Crude product separation: The crude product is separated by distillation in a recovery tower consisting of a low-boiling tower and a high-boiling tower. Unreacted chloroform and ethylene are distilled off the top of the low-boiling tower and returned to the reactor for recycling after condensation. 1,1,1,3-tetrachloropropane is distilled off the top of the high-boiling tower. The distillation separation yield is 98.5%.

[0028] No wastewater is generated during the entire reaction process. Hydrogen chloride gas is discharged and collected from the top of the reactor. The cyclic iron catalyst is retained in the reactor and can directly participate in the next reaction. The purity of the product 1,1,1,3-tetrachloropropane reaches 99.6%.

[0029] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for synthesizing 1,1,1,3-tetrachloropropane, characterized in that: With chloroform, chlorine gas ( Using chloroform and ethylene as reactants, and at least one of cyclic iron, ferrous chloride, ferric chloride, aluminum chloride, magnesium chloride, tributyl phosphate, triethyl phosphate, and triethyl phosphite as a solid chloride catalyst, chloroform is thoroughly mixed with the solid chloride catalyst to form a reaction mother liquor, which is then added to a reaction vessel reactor. Chlorine and ethylene are continuously introduced from the bottom of the reaction vessel reactor, causing the reactants to undergo an addition reaction to produce 1,1,1,3-tetrachloropropane. No wastewater is generated during the entire reaction process. After the reaction, the crude 1,1,1,3-tetrachloropropane product is sent to a recovery tower for distillation and separation. The unreacted chloroform and ethylene separated by the recovery tower are directly returned to the reaction vessel reactor for recycling, while the unreacted catalyst remains in the reactor and can participate in the next addition reaction.

2. The method for synthesizing 1,1,1,3-tetrachloropropane according to claim 1, characterized in that: The reaction temperature of the addition reaction is strictly controlled at 80-120℃. During the reaction, the temperature is maintained within this range by the temperature control system of the reactor to avoid the problem of additional by-products due to excessive temperature and the decrease in reaction rate due to excessive temperature. Moreover, the reaction conversion rate of raw materials and the selectivity of products can reach the optimal level within this temperature range.

3. The method for synthesizing 1,1,1,3-tetrachloropropane according to claim 1, characterized in that: The reaction pressure of the addition reaction is strictly controlled at 0.5-1.5 MPa. The pressure inside the reactor is maintained by atmospheric pressure boosting. This pressure range can ensure that chlorine and ethylene are fully dissolved in the mother liquor and react with chloroform, while avoiding the problems of increased equipment sealing requirements, increased production safety risks, and excessive equipment investment costs caused by high pressure.

4. The method for synthesizing 1,1,1,3-tetrachloropropane according to claim 1, characterized in that: The chloroform, chlorine ( The feed molar ratio of chloroform to ethylene is strictly controlled at 1.6:0.8:

1. During the reaction, raw materials are continuously added according to this molar ratio to ensure that chloroform is slightly in excess to fully consume chlorine and ethylene, reduce the generation of by-products caused by the imbalance of raw material ratio, and at the same time, excess chloroform can be recycled after separation in the subsequent recovery tower, effectively improving the overall utilization rate of raw materials.

5. The method for synthesizing 1,1,1,3-tetrachloropropane according to claim 1, characterized in that: The solid chloride catalyst is one or more of cyclic iron, ferrous chloride, ferric chloride, aluminum chloride, magnesium chloride, tributyl phosphate, triethyl phosphate, and triethyl phosphite, used in combination. When the catalyst is mixed with chloroform to form a reaction mother liquor, it is uniformly dispersed in the chloroform. The amount of catalyst added is 0.5%-5% of the mass of chloroform. This catalyst has high activity and strong selectivity, and good stability under reaction conditions of 80-120℃ and 0.5-1.5MPa. There is no catalyst loss after the reaction is completed, and it can be directly retained in the reactor to participate in the addition reaction again without the need for additional separation and replenishment.

6. The method for synthesizing 1,1,1,3-tetrachloropropane according to claim 1, characterized in that: The reactor is a specialized reaction vessel reactor, equipped with a temperature control system, a pressure control system, a raw material feeding system, and a gas distributor. Chlorine and ethylene are uniformly introduced into the reaction mother liquor through the gas distributor at the bottom of the reactor, allowing the gaseous raw materials to fully contact the chloroform and catalyst in the liquid phase, improving the mass transfer efficiency of the reaction, and ensuring that the addition reaction proceeds uniformly and continuously. The reactor is made of ordinary chemical-grade carbon steel, eliminating the need for special corrosion-resistant and high-pressure materials, resulting in low equipment investment costs.

7. The method for synthesizing 1,1,1,3-tetrachloropropane according to claim 1, characterized in that: The main reaction equation for the addition reaction is: → The reaction process generates only 1,1,1,3-tetrachloropropane and hydrogen chloride, with no other organic byproducts. The hydrogen chloride is discharged from the top of the reactor in gaseous form and can be collected and treated later. The entire reaction process generates no wastewater or waste residue, meeting the requirements for safe and environmentally friendly production.

8. The method for synthesizing 1,1,1,3-tetrachloropropane according to claim 1, characterized in that: The crude product is separated by distillation using a recovery tower system combining a low-boiling tower and a high-boiling tower. The crude product first enters the low-boiling tower, where unreacted chloroform and ethylene mixture is distilled off at the top. After condensation and liquefaction, this mixture is directly fed back to the feed end of the reaction vessel reactor for recycling. The material at the bottom of the low-boiling tower enters the high-boiling tower, where high-purity 1,1,1,3-tetrachloropropane is distilled off at the top. No residue is generated at the bottom of the high-boiling tower, and the yield of the distillation separation process reaches over 98%.

9. The method for synthesizing 1,1,1,3-tetrachloropropane according to claim 1, characterized in that: The synthesis method is a continuous production process. After the mother liquor of chloroform and catalyst is added to the reactor at once, chlorine and ethylene are continuously introduced from the bottom. The crude product is continuously discharged from the reactor outlet to the recovery tower. The recovered unreacted raw materials are continuously returned to the reactor. The entire production process does not need to be interrupted. The reaction rate is fast and the yield of 1,1,1,3-tetrachloropropane per unit time is high. The production efficiency is more than 50% higher than that of the existing batch process.

10. A method for synthesizing 1,1,1,3-tetrachloropropane according to any one of claims 1-9, characterized in that: The steps of the synthesis method are as follows: (1) Preparation of reaction mother liquor: A certain amount of chloroform is added to the reaction vessel reactor, and a solid chloride catalyst is added at 0.5% to 5% of the mass of chloroform. The mixture is stirred to make the catalyst evenly dispersed to form the reaction mother liquor. (2) Reaction condition adjustment: The temperature inside the reactor is raised to 80-120℃ by the temperature control system, and the pressure inside the reactor is adjusted to 0.5-1.5MPa and kept stable by the pressure control system; (3) Continuous feed of raw materials: Chlorine and ethylene are continuously fed into the mother liquor from the bottom of the reactor through a gas distributor at a molar ratio of 1.6:0.8:1, so that the three reactants can undergo an addition reaction. (4) Crude product discharge: The crude product 1,1,1,3-tetrachloropropane generated in the reaction is continuously discharged from the outlet of the reactor; (5) Crude product separation: The crude product is distilled and separated by a recovery tower system consisting of a low-boiling tower and a high-boiling tower to obtain high-purity 1,1,1,3-tetrachloropropane product. Unreacted chloroform and ethylene are recycled, and the catalyst is stored in the reactor for reuse.

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