A method for the continuous production of 1-chloro-2,2,3,3-tetrafluoropropane
By using a two-stage microchannel reactor for continuous chlorination-decomposition reaction, the problems of long reaction time and low yield in the preparation of 1-chloro-2,2,3,3-tetrafluoropropane were solved, achieving efficient and highly selective synthesis, which is suitable for the preparation of key intermediates for semiconductor industry cleaning agents.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- JUHUA GROUP TECH CENT
- Filing Date
- 2026-02-12
- Publication Date
- 2026-06-19
Smart Images
Figure CN122233864A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of organic synthesis technology, specifically relating to a method for the continuous preparation of 1-chloro-2,2,3,3-tetrafluoropropane. Background Technology
[0002] 1-Chloro-2,2,3,3-Tetrafluoropropane is characterized by the substitution of a chlorine atom at the 1-position of the propane skeleton with two fluorine atoms attached to the 2- and 3-position carbon atoms, and has the molecular formula ClCH2CF2CF2H. It is a hydrochlorofluorocarbon with significant industrial value. However, as a member of the hydrochlorofluorocarbon family, this molecule contains chlorine atoms and has a certain ozone depletion potential (ODP) and a significant global warming potential (GWP). Currently, it is mainly used as a key intermediate in the synthesis of fluorinated fine chemicals, and its application as a basic raw material in the preparation of detergents, foaming agents, and refrigerants has broad prospects.
[0003] 1-Chloro-2,2,3,3-Tetrafluoropropane has a variety of isomers. The differences between the isomers lie in the relative positions and connections of the chlorine and fluorine atoms on the carbon chain. The main isomers include positional isomers formed by the chlorine atom being attached to different carbon atoms. In the prior art, various methods for preparing 1-chloro-2,2,3,3-tetrafluoropropane isomers have been disclosed. For example, Chinese patent document CN116178097A discloses a method for highly selectively preparing 2-chloro-1,1,1,2-tetrafluoropropane, which includes the following steps: HF and 2-chloro-3,3,3-trifluoropropene are mixed in a molar ratio of 5 to 10:1 under the action of a catalyst and reacted at 350 to 400°C. The contact time between the raw materials and the catalyst is 6 to 8 seconds to obtain 2-chloro-1,1,1,2-tetrafluoropropane. The catalyst is a nickel, chromium, or a combination thereof metal catalyst supported on activated carbon. The catalyst is calcined in two steps under one or more combined atmospheres of air, nitrogen, and water vapor. Chinese patent document CN110343029A discloses a method for preparing 3-chloro-1,1,1,3-tetrafluoropropane. This method involves the liquid-phase fluorination of hydrogen fluoride with 1-chloro-3,3,3-trifluoropropene in the presence of a liquid-phase composite catalyst to prepare 3-chloro-1,1,1,3-tetrafluoropropane. The reaction temperature is 50℃~150℃, and the reaction time is 0.5h~10h. The liquid-phase composite catalyst consists of a metal fluoride and a compounding agent. The metal fluoride is TaF5, NbF5, TiF4, or SnF4, and the compounding agent is an organic amine. It is evident that the addition reaction of olefins with hydrogen fluoride is difficult to prepare 1-chloro-2,2,3,3-tetrafluoropropane; it can only be used to prepare isomers of 1-chloro-2,2,3,3-tetrafluoropropane.
[0004] Patent document CN110167907A discloses a method for producing 3-chloro-1,1,2,2-tetrafluoropropane. The method includes: a first step, reacting TFPO with thionyl chloride in the presence of DMF to produce 2,2,3,3-tetrafluoropropanesulfonyl chloride; and a second step, simultaneously thermally decomposing and distilling the 2,2,3,3-tetrafluoropropanesulfonyl chloride to obtain a distillate containing 244 Ca. However, this invention uses conventional reactors such as high-pressure reactors and glass flasks for the reaction, resulting in long reaction times, low yields, and low efficiency.
[0005] Therefore, it is of great significance to develop a method for the continuous synthesis of 1-chloro-2,2,3,3-tetrafluoropropane with high efficiency, high selectivity and high yield. Summary of the Invention
[0006] This invention provides a method for the continuous preparation of 1-chloro-2,2,3,3-tetrafluoropropane, which enables the reaction to be completed in a short time, improving reaction efficiency while ensuring reaction yield.
[0007] The specific technical solution adopted is as follows: A method for the continuous preparation of 1-chloro-2,2,3,3-tetrafluoropropane includes the following steps: 1-Chloro-2,2,3,3-Tetrafluoropropane was prepared by a continuous chlorination-decomposition reaction in a two-stage microchannel reactor using tetrafluoropropanol (2,2,3,3-tetrafluoropropanol) and thionyl chloride as raw materials in an aprotic polar solvent.
[0008] This invention conducts a continuous chlorination-decomposition reaction in a two-stage microchannel reactor. The continuous flow operation significantly improves process stability and product yield compared to conventional batch operation, reduces side reactions, and at the same time, the system has a small liquid holdup, high safety, and greatly shortens the reaction time and improves reaction efficiency.
[0009] Furthermore, the aprotic polar solvent is N,N-dimethylformamide and / or N,N-dimethylacetamide.
[0010] Furthermore, the two-stage microchannel reactor includes a chlorination microchannel reactor and a decomposition microchannel reactor connected in series. The chlorination reaction of tetrafluoropropanol and thionyl chloride is carried out in the chlorination microchannel reactor, and the thermal decomposition of the chlorination reaction products is carried out in the decomposition microchannel reactor.
[0011] Furthermore, tetrafluoropropanol and aprotic polar solvent are premixed, and the premixed solution and thionyl chloride are continuously pumped into a chlorination microchannel reactor for mixing and reaction. The resulting chlorination reaction product flows out continuously and is then pumped into a decomposition microchannel reactor for thermal decomposition. The obtained thermal decomposition reaction product is post-processed to prepare 1-chloro-2,2,3,3-tetrafluoropropane.
[0012] The method of this invention requires maintaining a stable and continuous feed and discharge between the two-stage microchannel reactors. Abnormalities in the reaction within the chlorination microchannel reactor will affect the reaction efficiency within the decomposition microchannel reactor.
[0013] Preferably, in the chlorination microchannel reactor, the reaction temperature is 0~40℃, the reaction pressure is atmospheric pressure, and the residence time of the reactants is 5~30 min.
[0014] Preferably, in the decomposition microchannel reactor, the reaction temperature is 90~115℃, the reaction pressure is atmospheric pressure, and the residence time of the reactants is 5~20 min.
[0015] Preferably, the premixed solution is pumped into the chlorination microchannel reactor at a rate of 5-50 mL / min, thionyl chloride is pumped into the chlorination microchannel reactor at a rate of 5-70 mL / min, and the chlorination reaction products are pumped into the decomposition microchannel reactor at a rate of 10-130 mL / min.
[0016] Furthermore, the molar ratio of tetrafluoropropanol to thionyl chloride is 1:1 to 1.5, and the amount of aprotic polar solvent used is 5% to 20% of the mass of tetrafluoropropanol.
[0017] Preferably, in the chlorination reaction of tetrafluoropropanol and thionyl chloride, trialkylphosphine oxide or triphenylphosphine oxide is also added. Trialkylphosphine oxide or triphenylphosphine oxide acts as a catalyst to further promote the chlorination reaction. Its phosphorus center has strong nucleophilicity and can efficiently activate the substrate under mild conditions, thereby improving reaction efficiency and product yield.
[0018] More preferably, in the chlorination reaction of tetrafluoropropanol and thionyl chloride, trialkylphosphine oxide is added, and the molar ratio of tetrafluoropropanol to trialkylphosphine oxide is 1:0.01 to 0.1.
[0019] Specifically, tetrafluoropropanol and aprotic polar solvents are premixed, and the premixed solution, thionyl chloride, and trialkylphosphine oxide are continuously pumped into a chlorination microchannel reactor for mixing and reaction. The resulting chlorination reaction product flows out continuously and is then pumped into a decomposition microchannel reactor for thermal decomposition. The obtained thermal decomposition reaction product is post-processed to prepare 1-chloro-2,2,3,3-tetrafluoropropane.
[0020] Furthermore, the outlet of the two-stage microchannel reactor is connected to a condenser, and the liquid obtained by condensation of the thermal decomposition reaction products is purified by distillation to prepare 1-chloro-2,2,3,3-tetrafluoropropane.
[0021] The present invention also provides the application of the continuous preparation method of 1-chloro-2,2,3,3-tetrafluoropropane in the synthesis of fluorine-containing fine chemicals.
[0022] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The method for preparing 1-chloro-2,2,3,3-tetrafluoropropane in this invention is a two-step continuous flow process. This method can complete the reaction in a short time (≤50 min), which improves the reaction efficiency while ensuring the reaction yield and can obtain more target products per unit time.
[0023] (2) The present invention carries out a continuous chlorination-decomposition reaction in a two-stage microchannel reactor. The continuous flow operation significantly improves the process stability and product yield compared with the conventional batch operation, reduces side reactions, and at the same time, the system has a small liquid holdup and high safety.
[0024] (3) In the chlorination reaction of tetrafluoropropanol and thionyl chloride, the present invention adds trialkylphosphine oxide or triphenylphosphine oxide as a catalyst. These catalysts are widely available, have strong catalytic performance, can reduce the amount of by-products generated, further improve selectivity, and prepare 1-chloro-2,2,3,3-tetrafluoropropane in higher yield.
[0025] (4) The 1-chloro-2,2,3,3-tetrafluoropropane prepared by the present invention is a key intermediate for the preparation of 1-chloro-3,3,3-trifluoropropene, a cleaning agent for the semiconductor industry. The development of the continuous synthesis route of the present invention provides important reference for the industrial production of the cleaning agent 1-chloro-3,3,3-trifluoropropene.
[0026] (5) The nonprotic polar solvent used in this invention can be recycled and reused, and the route is green and economical. Attached Figure Description
[0027] Figure 1 This is a schematic diagram of a continuous chlorination-decomposition reaction using a two-stage microchannel reactor. Detailed Implementation
[0028] To make the objectives, features, and advantages of this invention more apparent and understandable, a detailed description is provided below through specific embodiments. Many specific details are set forth in the following description to provide a thorough understanding of the invention. However, the invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below. Technical features in various embodiments of the invention can be combined appropriately without mutual conflict.
[0029] Unless otherwise specified, the operating methods in the following examples are generally performed under conventional conditions or as recommended by the manufacturer. Contents not described in detail in this specification are prior art known to those skilled in the art. Unless otherwise specified, the experimental materials used in the examples below can be purchased from conventional biochemical reagent companies.
[0030] All scopes disclosed herein include endpoints, and endpoints can be combined independently of each other.
[0031] Unless otherwise stated herein or clearly contradicted by the context, the terms “an”, “a”, and “the” do not imply a limitation of quantity and should be interpreted to cover both the singular and the plural.
[0032] In this invention, a schematic diagram of a continuous chlorination-decomposition reaction using a two-stage microchannel reactor is shown below. Figure 1 As shown. Specifically, the two-stage microchannel reactor includes a chlorination microchannel reactor and a decomposition microchannel reactor connected in series.
[0033] This invention uses tetrafluoropropanol and thionyl chloride as raw materials to prepare 1-chloro-2,2,3,3-tetrafluoropropane through a continuous chlorination-decomposition reaction in an aprotic polar solvent using a two-stage microchannel reactor. The specific operation steps are as follows: tetrafluoropropanol and the aprotic polar solvent are premixed; the premixed solution and thionyl chloride are continuously pumped into the chlorination microchannel reactor for mixing and reaction; the chlorination reaction product is continuously discharged and then pumped into the decomposition microchannel reactor for thermal decomposition reaction; the obtained thermal decomposition reaction product is post-processed to prepare 1-chloro-2,2,3,3-tetrafluoropropane.
[0034] In some preferred embodiments, the aprotic polar solvent is N,N-dimethylformamide and / or N,N-dimethylacetamide.
[0035] In some preferred embodiments, the reaction temperature in the chlorination microchannel reactor is 0~40°C, the reaction pressure is atmospheric pressure, and the residence time of the reactants is 5~30 min.
[0036] In some preferred embodiments, the reaction temperature in the decomposition microchannel reactor is 90~115℃, the reaction pressure is atmospheric pressure, and the residence time of the reactants is 5~20 min.
[0037] In some preferred embodiments, the molar ratio of tetrafluoropropanol to thionyl chloride is 1:1 to 1.5; the amount of aprotic polar solvent is 5% to 20% of the mass of tetrafluoropropanol; the actual rate at which the premixed solution is pumped into the chlorination microchannel reactor is 5-50 mL / min, the actual rate at which thionyl chloride is pumped into the chlorination microchannel reactor is 5-70 mL / min, and the actual rate at which the chlorination reaction product is pumped into the decomposition microchannel reactor is 10-130 mL / min.
[0038] In some preferred embodiments, trialkylphosphine oxide or triphenylphosphine oxide is also added to the chlorination reaction of tetrafluoropropanol and thionyl chloride. When trialkylphosphine oxide is added, the molar ratio of tetrafluoropropanol to trialkylphosphine oxide is 1:0.01 to 0.1. Specifically, tetrafluoropropanol and aprotic polar solvent are premixed, and the premixed solution, thionyl chloride and trialkylphosphine oxide are continuously pumped into a chlorination microchannel reactor for mixing and reaction. The chlorination reaction product is continuously discharged and then pumped into a decomposition microchannel reactor for thermal decomposition reaction. The obtained thermal decomposition reaction product is post-processed to prepare 1-chloro-2,2,3,3-tetrafluoropropane.
[0039] In some preferred embodiments, the outlet of the two-stage microchannel reactor is connected to a condenser, and the liquid obtained by condensation of the thermal decomposition reaction products is purified by distillation to prepare 1-chloro-2,2,3,3-tetrafluoropropane.
[0040] In the following examples and comparative examples, the tetrafluoropropanol used specifically refers to 2,2,3,3-tetrafluoropropanol.
[0041] Example 1 S1. Tetrafluoropropanol and N,N-dimethylformamide are premixed to obtain a premixed solution. The premixed solution and thionyl chloride are continuously pumped into the primary chlorination microchannel reactor through metering pump 1 and metering pump 2, respectively, to carry out the chlorination reaction and obtain the reaction products. The molar ratio of tetrafluoropropanol to thionyl chloride is 1:1.1, the amount of N,N-dimethylformamide is 10% of the mass of tetrafluoropropanol, the actual feed rate of the premixed solution is 42.9 mL / min, and the actual feed rate of thionyl chloride is 34.8 mL / min. At the same time, the reaction temperature in the chlorination microchannel reactor is controlled at 20℃, the reaction pressure is at atmospheric pressure, and the residence time of the reactants is 5 min.
[0042] S2. The chlorination reaction product obtained in S1 is continuously pumped into the secondary decomposition microchannel reactor at an actual rate of 77.7 mL / min using metering pump 3. The reaction temperature in the decomposition microchannel reactor is controlled at 110℃, the reaction pressure is at atmospheric pressure, and the residence time of the reactants is 20 min. The thermal decomposition reaction product passes through a condenser, and the gas obtained from the condensation enters the alkaline absorption bottle through the gas phase pipeline. The liquid obtained from the condensation is crude 1-chloro-2,2,3,3-tetrafluoropropane with a single-pass yield of 90.6%. The crude 1-chloro-2,2,3,3-tetrafluoropropane is then separated by distillation to obtain 1-chloro-2,2,3,3-tetrafluoropropane with a purity of 99%.
[0043] Example 2 S1. Tetrafluoropropanol and N,N-dimethylformamide are premixed to obtain a premixed solution. The premixed solution and thionyl chloride are continuously pumped into the primary chlorination microchannel reactor through metering pump 1 and metering pump 2, respectively, to carry out the chlorination reaction and obtain the reaction products. The molar ratio of tetrafluoropropanol to thionyl chloride is 1:1.2, the amount of N,N-dimethylformamide is 15% of the mass of tetrafluoropropanol, the actual feed rate of the premixed solution is 14.0 mL / min, and the actual feed rate of thionyl chloride is 11.6 mL / min. At the same time, the reaction temperature in the chlorination microchannel reactor is controlled at 30℃, the reaction pressure is at atmospheric pressure, and the residence time of the reactants is 20 min.
[0044] S2. The chlorination reaction product obtained in S1 is continuously pumped into the secondary decomposition microchannel reactor at an actual rate of 25.6 mL / min using metering pump 3. The reaction temperature in the decomposition microchannel reactor is controlled at 115℃, the reaction pressure at atmospheric pressure, and the residence time of the reactants is 10 min. The thermal decomposition reaction product passes through a condenser, and the condensed gas enters the alkaline absorption bottle through a gas phase pipeline. The condensed liquid is crude 1-chloro-2,2,3,3-tetrafluoropropane, with a single-pass yield of 88.5%. The crude 1-chloro-2,2,3,3-tetrafluoropropane is then subjected to distillation to obtain 1-chloro-2,2,3,3-tetrafluoropropane with a purity of 99%.
[0045] Example 3 S1. Tetrafluoropropanol and N,N-dimethylformamide are premixed to obtain a premixed solution. The premixed solution and thionyl chloride are continuously pumped into the primary chlorination microchannel reactor through metering pump 1 and metering pump 2, respectively, to carry out the chlorination reaction and obtain the reaction products. The molar ratio of tetrafluoropropanol to thionyl chloride is 1:1.3, the amount of N,N-dimethylacetamide is 10% of the mass of tetrafluoropropanol, the actual feed rate of the premixed solution is 9.9 mL / min, and the actual feed rate of thionyl chloride is 9.7 mL / min. At the same time, the reaction temperature in the chlorination microchannel reactor is controlled at 10℃, the reaction pressure is at atmospheric pressure, and the residence time of the reactants is 30 min.
[0046] S2. The chlorination reaction product obtained in S1 is continuously pumped into the secondary decomposition microchannel reactor at an actual rate of 19.6 mL / min using metering pump 3. The reaction temperature in the decomposition microchannel reactor is controlled at 100℃, the reaction pressure is at atmospheric pressure, and the residence time of the reactants is 20 min. The thermal decomposition reaction product passes through a condenser, and the gas obtained from the condensation enters the alkaline absorption bottle through the gas phase pipeline. The liquid obtained from the condensation is crude 1-chloro-2,2,3,3-tetrafluoropropane with a single-pass yield of 91.2%. The crude 1-chloro-2,2,3,3-tetrafluoropropane is then separated by distillation to obtain 1-chloro-2,2,3,3-tetrafluoropropane with a purity of 99%.
[0047] Example 4 S1. Tetrafluoropropanol and N,N-dimethylformamide are premixed to obtain a premixed solution. The premixed solution and thionyl chloride are continuously pumped into the primary chlorination microchannel reactor through metering pump 1 and metering pump 2, respectively, to carry out the chlorination reaction and obtain the reaction products. The molar ratio of tetrafluoropropanol to thionyl chloride is 1:1.4, the amount of N,N-dimethylacetamide is 5% of the mass of tetrafluoropropanol, the actual feed rate of the premixed solution is 23.4 mL / min, and the actual feed rate of thionyl chloride is 25.5 mL / min. At the same time, the reaction temperature in the chlorination microchannel reactor is controlled at 0℃, the reaction pressure is at atmospheric pressure, and the residence time of the reactants is 10 min.
[0048] S2. The chlorination reaction product obtained in S1 is continuously pumped into the secondary decomposition microchannel reactor at an actual rate of 48.9 mL / min using metering pump 3. The reaction temperature in the decomposition microchannel reactor is controlled at 90℃, the reaction pressure is at atmospheric pressure, and the residence time of the reactants is 10 min. The thermal decomposition reaction product passes through a condenser, and the gas obtained from the condensation enters the alkaline absorption bottle through the gas phase pipeline. The liquid obtained from the condensation is crude 1-chloro-2,2,3,3-tetrafluoropropane with a single-pass yield of 89.2%. The crude 1-chloro-2,2,3,3-tetrafluoropropane is then separated by distillation to obtain 1-chloro-2,2,3,3-tetrafluoropropane with a purity of 99%.
[0049] Example 5 S1. Tetrafluoropropanol and N,N-dimethylformamide are premixed to obtain a premixed solution. The premixed solution and thionyl chloride are continuously pumped into the primary chlorination microchannel reactor through metering pump 1 and metering pump 2, respectively, to carry out the chlorination reaction and obtain the reaction products. The molar ratio of tetrafluoropropanol to thionyl chloride is 1:1.5, the amount of N,N-dimethylacetamide is 20% of the mass of tetrafluoropropanol, the actual feed rate of the premixed solution is 64.3 mL / min, and the actual feed rate of thionyl chloride is 62.0 mL / min. At the same time, the reaction temperature in the chlorination microchannel reactor is controlled at 40℃, the reaction pressure is at atmospheric pressure, and the residence time of the reactants is 20 min.
[0050] S2. The chlorination reaction product obtained in S1 is continuously pumped into the secondary decomposition microchannel reactor at an actual rate of 126.3 mL / min using metering pump 3. The reaction temperature in the decomposition microchannel reactor is controlled at 110℃, the reaction pressure is at atmospheric pressure, and the residence time of the reactants is 15 min. The thermal decomposition reaction product passes through a condenser, and the gas obtained from the condensation enters the alkaline absorption bottle through the gas phase pipeline. The liquid obtained from the condensation is crude 1-chloro-2,2,3,3-tetrafluoropropane with a single-pass yield of 92.0%. The crude 1-chloro-2,2,3,3-tetrafluoropropane is then separated by distillation to obtain 1-chloro-2,2,3,3-tetrafluoropropane with a purity of 99%.
[0051] Example 6 S1. Tetrafluoropropanol and N,N-dimethylformamide are premixed to obtain a premixed solution. The premixed solution and thionyl chloride are continuously pumped into the primary chlorination microchannel reactor through metering pump 1 and metering pump 2, respectively, to carry out the chlorination reaction and obtain the reaction products. The molar ratio of tetrafluoropropanol to thionyl chloride is 1:1.1, the amount of N,N-dimethylformamide is 15% of the mass of tetrafluoropropanol, the actual feed rate of the premixed solution is 32.5 mL / min, and the actual feed rate of thionyl chloride is 24.6 mL / min. At the same time, the reaction temperature in the chlorination microchannel reactor is controlled at 20℃, the reaction pressure is at atmospheric pressure, and the residence time of the reactants is 15 min.
[0052] S2. The chlorination reaction product obtained in S1 is continuously pumped into the secondary decomposition microchannel reactor at an actual rate of 57.1 mL / min using metering pump 3. The reaction temperature in the decomposition microchannel reactor is controlled at 120℃, the reaction pressure is at atmospheric pressure, and the residence time of the reactants is 5 min. The thermal decomposition reaction product passes through a condenser, and the gas obtained from the condensation enters the alkaline absorption bottle through the gas phase pipeline. The liquid obtained from the condensation is crude 1-chloro-2,2,3,3-tetrafluoropropane with a single-pass yield of 86.3%. The crude 1-chloro-2,2,3,3-tetrafluoropropane is then separated by distillation to obtain 1-chloro-2,2,3,3-tetrafluoropropane with a purity of 99%.
[0053] Example 7 S1. Tetrafluoropropanol and N,N-dimethylformamide are premixed to obtain a premixed solution. The premixed solution and thionyl chloride are continuously pumped into the primary chlorination microchannel reactor through metering pump 1 and metering pump 2, respectively, to carry out the chlorination reaction and obtain the reaction products. The molar ratio of tetrafluoropropanol to thionyl chloride is 1:1.2, the amount of N,N-dimethylformamide is 15% of the mass of tetrafluoropropanol, the actual feed rate of the premixed solution is 28.0 mL / min, and the actual feed rate of thionyl chloride is 23.2 mL / min. At the same time, the reaction temperature in the chlorination microchannel reactor is controlled at 20℃, the reaction pressure is at atmospheric pressure, and the residence time of the reactants is 15 min.
[0054] S2. The chlorination reaction product obtained in S1 is continuously pumped into the secondary decomposition microchannel reactor at an actual rate of 51.2 mL / min using metering pump 3. The reaction temperature in the decomposition microchannel reactor is controlled at 120℃, the reaction pressure is at atmospheric pressure, and the residence time of the reactants is 8 min. The thermal decomposition reaction product passes through a condenser, and the gas obtained from the condensation enters the alkaline absorption bottle through the gas phase pipeline. The liquid obtained from the condensation is crude 1-chloro-2,2,3,3-tetrafluoropropane with a single-pass yield of 89.5%. The crude 1-chloro-2,2,3,3-tetrafluoropropane is then separated by distillation to obtain 1-chloro-2,2,3,3-tetrafluoropropane with a purity of 99%.
[0055] Example 8 S1. Tetrafluoropropanol and N,N-dimethylformamide are premixed to obtain a premixed solution. The premixed solution and thionyl chloride are continuously pumped into the primary chlorination microchannel reactor through metering pump 1 and metering pump 2, respectively, to carry out the chlorination reaction and obtain the reaction products. The molar ratio of tetrafluoropropanol to thionyl chloride is 1:1.4, the amount of N,N-dimethylacetamide is 10% of the mass of tetrafluoropropanol, the feed rate of the premixed solution is 24.8 mL / min, and the feed rate of thionyl chloride is 25.5 mL / min. At the same time, the reaction temperature in the chlorination microchannel reactor is controlled at 10℃, the reaction pressure is at atmospheric pressure, and the residence time of the reactants is 20 min.
[0056] S2. The chlorination reaction product obtained in S1 is continuously pumped into the secondary decomposition microchannel reactor at an actual rate of 50.3 mL / min using metering pump 3. The reaction temperature in the decomposition microchannel reactor is controlled at 90℃, the reaction pressure is at atmospheric pressure, and the residence time of the reactants is 10 min. The thermal decomposition reaction product passes through a condenser, and the gas obtained from the condensation enters the alkaline absorption bottle through the gas phase pipeline. The liquid obtained from the condensation is crude 1-chloro-2,2,3,3-tetrafluoropropane with a single-pass yield of 89.2%. The crude 1-chloro-2,2,3,3-tetrafluoropropane is then separated by distillation to obtain 1-chloro-2,2,3,3-tetrafluoropropane with a purity of 99%.
[0057] Example 9 S1. Tetrafluoropropanol and N,N-dimethylformamide are premixed to obtain a premixed solution. The premixed solution, thionyl chloride, and trialkylphosphine oxide are continuously pumped into the primary chlorination microchannel reactor through metering pumps 1, 2, and 4, respectively, to carry out the chlorination reaction and obtain the reaction products. The molar ratio of tetrafluoropropanol to thionyl chloride is 1:1.2, the molar ratio of tetrafluoropropanol to trialkylphosphine oxide is 1:0.05, the amount of N,N-dimethylformamide is 15% of the mass of tetrafluoropropanol, the feed rate of the premixed solution is 14.0 mL / min, the feed rate of thionyl chloride is 11.6 mL / min, and the feed rate of trialkylphosphine oxide is 2.5 mL / min. At the same time, the reaction temperature in the chlorination microchannel reactor is controlled at 30℃, the reaction pressure is at atmospheric pressure, and the residence time of the reactants is 5 min.
[0058] S2. The chlorination reaction product obtained in S1 is continuously pumped into the secondary decomposition microchannel reactor at a rate of 28.1 mL / min using metering pump 3. The reaction temperature in the decomposition microchannel reactor is controlled at 115℃, the reaction pressure at atmospheric pressure, and the residence time of the reactants is 10 min. The thermal decomposition reaction product passes through a condenser, and the condensed gas enters the alkaline absorption bottle through a gas phase pipeline. The condensed liquid is crude 1-chloro-2,2,3,3-tetrafluoropropane, with a single-pass yield of 94.5%. The crude 1-chloro-2,2,3,3-tetrafluoropropane is then subjected to distillation to obtain 1-chloro-2,2,3,3-tetrafluoropropane with a purity of 99%.
[0059] Example 10 S1. Tetrafluoropropanol and N,N-dimethylformamide are premixed to obtain a premixed solution. The premixed solution and thionyl chloride are continuously pumped into the primary chlorination microchannel reactor through metering pump 1 and metering pump 2, respectively, to carry out the chlorination reaction and obtain the reaction products. The molar ratio of tetrafluoropropanol to thionyl chloride is 1:1.1, the amount of N,N-dimethylformamide is 10% of the mass of tetrafluoropropanol, the actual feed rate of the premixed solution is 42.9 mL / min, and the actual feed rate of thionyl chloride is 34.8 mL / min. At the same time, the reaction temperature in the chlorination microchannel reactor is controlled at 10℃, the reaction pressure is at atmospheric pressure, and the residence time of the reactants is 10 min.
[0060] S2. The chlorination reaction product obtained in S1 is continuously pumped into the secondary decomposition microchannel reactor at an actual rate of 77.7 mL / min using metering pump 3. The reaction temperature in the decomposition microchannel reactor is controlled at 110℃, the reaction pressure is at atmospheric pressure, and the residence time of the reactants is 20 min. The thermal decomposition reaction product passes through a condenser, and the gas obtained from the condensation enters the alkaline absorption bottle through the gas phase pipeline. The liquid obtained from the condensation is crude 1-chloro-2,2,3,3-tetrafluoropropane with a single-pass yield of 90.9%. The crude 1-chloro-2,2,3,3-tetrafluoropropane is then separated by distillation to obtain 1-chloro-2,2,3,3-tetrafluoropropane with a purity of 99%.
[0061] Comparative Example 1 Tetrafluoropropanol (132.06 g) and N,N-dimethylformamide (13.2 g) were mixed and added dropwise to a three-necked flask containing thionyl chloride (130.87 g) for chlorination. Under stirring, the molar ratio of tetrafluoropropanol to thionyl chloride was 1:1.1, and the amount of N,N-dimethylformamide was 10% of the mass of tetrafluoropropanol. The reaction temperature was 20 °C, and the reaction continued for 1 h after the addition was complete. After the reaction was completed, the reaction solution was heated to 90-115 °C for thermal decomposition distillation for 6 hours. The distillate was collected and washed with ice water and alkali to obtain 1-chloro-2,2,3,3-tetrafluoropropane with a yield of 82.5%.
[0062] Comparative Example 2 Tetrafluoropropanol (132.06 g) and N,N-dimethylformamide (26.4 g) were mixed and added dropwise to a three-necked flask containing thionyl chloride (118.97 g) for chlorination. Under stirring, the molar ratio of tetrafluoropropanol to thionyl chloride was 1:1, and the amount of N,N-dimethylformamide was 20% of the mass of tetrafluoropropanol. The reaction temperature was 10 °C, and the reaction continued for 2 hours after the addition was complete. After the reaction was completed, the reaction solution was heated to 90-115 °C for thermal decomposition distillation for 6.5 hours. The distillate was collected and washed with ice water and alkali to obtain the intermediate HCFC-244ca, with a yield of 83.6%.
[0063] Sample Analysis As can be seen from the above data, the main difference between the comparative example and the embodiment lies in whether a continuous process is used. The single-pass yield of the continuous reaction is not much different from the total yield of the batch reaction. However, the method of preparing 1-chloro-2,2,3,3-tetrafluoropropane using a two-stage microchannel reactor can complete the reaction in a shorter time and obtain a high throughput of the target product per unit time, which is more efficient.
[0064] The embodiments described above provide a detailed explanation of the technical solutions of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, additions, or similar substitutions made within the scope of the principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for the continuous preparation of 1-chloro-2,2,3,3-tetrafluoropropane, characterized in that, Includes the following steps: 1-Chloro-2,2,3,3-Tetrafluoropropane was prepared by a continuous chlorination-decomposition reaction in a two-stage microchannel reactor using tetrafluoropropanol and thionyl chloride as raw materials in an aprotic polar solvent.
2. The method for continuous preparation of 1-chloro-2,2,3,3-tetrafluoropropane according to claim 1, characterized in that, The aprotic polar solvents are N,N-dimethylformamide and / or N,N-dimethylacetamide.
3. The method for continuous preparation of 1-chloro-2,2,3,3-tetrafluoropropane according to claim 1, characterized in that, The two-stage microchannel reactor consists of a chlorination microchannel reactor and a decomposition microchannel reactor connected in series. The chlorination reaction of tetrafluoropropanol and thionyl chloride is carried out in the chlorination microchannel reactor, and the thermal decomposition of the chlorination reaction products is carried out in the decomposition microchannel reactor.
4. The method for continuous preparation of 1-chloro-2,2,3,3-tetrafluoropropane according to claim 1, characterized in that, Tetrafluoropropanol and aprotic polar solvents are premixed. The premixed solution and thionyl chloride are continuously pumped into a chlorination microchannel reactor for mixing and reaction. The resulting chlorination reaction product flows out continuously and is then pumped into a decomposition microchannel reactor for thermal decomposition. The obtained thermal decomposition reaction product is post-processed to prepare 1-chloro-2,2,3,3-tetrafluoropropane.
5. The method for continuous preparation of 1-chloro-2,2,3,3-tetrafluoropropane according to claim 4, characterized in that, In the chlorination microchannel reactor, the reaction temperature is 0~40℃, the reaction pressure is atmospheric pressure, and the residence time of the reactants is 5~30 min.
6. The method for continuous preparation of 1-chloro-2,2,3,3-tetrafluoropropane according to claim 4, characterized in that, In the decomposition microchannel reactor, the reaction temperature is 90~115℃, the reaction pressure is atmospheric pressure, and the residence time of the reactants is 5~20min.
7. The method for continuous preparation of 1-chloro-2,2,3,3-tetrafluoropropane according to claim 4, characterized in that, The premixed solution was pumped into the chlorination microchannel reactor at a rate of 5-50 mL / min, and thionyl chloride was pumped into the chlorination microchannel reactor at a rate of 5-70 mL / min.
8. The method for continuous preparation of 1-chloro-2,2,3,3-tetrafluoropropane according to claim 4, characterized in that, The chlorination reaction products are pumped into the decomposition microchannel reactor at a rate of 10-130 mL / min.
9. The method for continuous preparation of 1-chloro-2,2,3,3-tetrafluoropropane according to claim 1, characterized in that, The molar ratio of tetrafluoropropanol to thionyl chloride is 1:1 to 1.
5.
10. The method for continuous preparation of 1-chloro-2,2,3,3-tetrafluoropropane according to claim 1, characterized in that, The amount of aprotic polar solvent used is 5% to 20% of the mass of tetrafluoropropanol.
11. The method for continuous preparation of 1-chloro-2,2,3,3-tetrafluoropropane according to claim 1, characterized in that, In the chlorination reaction of tetrafluoropropanol and thionyl chloride, trialkylphosphine oxide or triphenylphosphine oxide is also added.
12. The method for continuous preparation of 1-chloro-2,2,3,3-tetrafluoropropane according to claim 11, characterized in that, In the chlorination reaction of tetrafluoropropanol and thionyl chloride, trialkylphosphine oxide is added, and the molar ratio of tetrafluoropropanol to trialkylphosphine oxide is 1:0.01 to 0.
1.
13. The method for continuous preparation of 1-chloro-2,2,3,3-tetrafluoropropane according to claim 12, characterized in that, Tetrafluoropropanol and aprotic polar solvents are premixed. The premixed solution, thionyl chloride, and trialkylphosphine oxide are continuously pumped into a chlorination microchannel reactor for mixing and reaction. The resulting chlorination reaction product flows out continuously and is then pumped into a decomposition microchannel reactor for thermal decomposition. The obtained thermal decomposition reaction product is post-processed to prepare 1-chloro-2,2,3,3-tetrafluoropropane.
14. The method for continuous preparation of 1-chloro-2,2,3,3-tetrafluoropropane according to claim 1, characterized in that, The outlet of the two-stage microchannel reactor is connected to a condenser. The liquid obtained by condensation of the thermal decomposition reaction products is purified by distillation to prepare 1-chloro-2,2,3,3-tetrafluoropropane.
15. The application of the continuous preparation method of 1-chloro-2,2,3,3-tetrafluoropropane according to any one of claims 1-14 in the synthesis of fluorine-containing fine chemicals.