Continuous production method for 1,1,1,2,3-pentachloropropane

Abstract

The present invention discloses a continuous method for producing 1,1,1,2,3-pentachloropropane, in which 1,1,1,3-tetrachloropropane and chlorine gas are introduced into a reactor in series and reacted over a solid oxide catalyst to produce 1,1,1,2,3-pentachloropropane. The reaction is a gas-liquid-solid three-phase reaction, in which 1,1,1,3-tetrachloropropane is introduced from the top of the reactor and chlorine gas is introduced from the top or bottom. The mild reaction conditions and simple process have the advantages of low exhaust gas, wastewater, and solid waste, high conversion of 1,1,1,3-tetrachloropropane, high product selectivity, catalyst stability, and continuous production, making this process highly suitable for industrial applications.

Description

[Technical Field]

[0001] The present invention relates to a process for producing chlorinated hydrocarbons, and more particularly to a continuous process for producing 1,1,1,2,3-pentachloropropane. [Background technology]

[0002] 2,3,3,3-Tetrafluoropropene (HFO-1234yf), a new generation environmentally friendly refrigerant, has an ozone depletion potential (ODP) of 0 and a greenhouse effect potential (GWP) of only 4 and is considered an ideal replacement for 1,1,1,2-tetrafluoroethane (HFC-134a, ODP=0, GWP=1430).

[0003] In recent years, research into technologies for producing 2,3,3,3-tetrafluoropropene has entered a period of rapid development. Among these methods, synthesizing 2,3,3,3-tetrafluoropropene using 1,1,2,3-tetrachloropropene as a raw material is one of the important methods. 1,1,2,3-tetrachloropropene is obtained by dehydrochlorinating 1,1,1,2,3-pentachloropropane. Therefore, how to efficiently synthesize 1,1,1,2,3-pentachloropropane is the key to producing 2,3,3,3-tetrafluoropropene.

[0004] There are two main methods for producing 1,1,1,2,3-pentachloropropane. The first is an indirect method (two-step method) in which 1,1,1,3-tetrachloropropane is first dehydrochlorinated to obtain 1,1,3-trichloropropene and / or 3,3,3-trichloropropene, which is then chlorinated to synthesize 1,1,1,2,3-pentachloropropane. The second is a direct method in which 1,1,1,3-tetrachloropropane is directly chlorinated to produce 1,1,1,2,3-pentachloropropane.

[0005] For example, CN108069817A discloses a one-pot process for producing 1,1,1,2,3-pentachloropropane with high selectivity and yield. This process involves dehydrochlorinating 1,1,1,3-tetrachloropropane to obtain 1,1,3-trichloropropene. When the 1,1,3-trichloropropene content in the system reaches 4-20%, chlorine gas is introduced to continue the reaction. After the introduction of chlorine gas, the 1,1,3-trichloropropene content in the reaction system is controlled to 1-6%, and the reaction is terminated when the 1,1,1,2,3-pentachloropropane content in the system reaches 90-99%. The catalyst used is anhydrous ferric chloride or a composite catalyst consisting of iron powder and anhydrous ferric chloride, and the product yield is 95%. However, this invention does not address the stability of the catalyst, and many side reactions, such as polymerization and isomerization, still exist. On the other hand, this reaction is characterized in that it requires careful attention to the content of each substance in the reaction system, which makes the operation inconvenient.

[0006] CN109232173A also discloses a continuous method for producing 1,1,1,2,3-pentachloropropane. This invention uses trichloropropene as a raw material, which is introduced separately from chlorine gas into a microchannel preheater for preheating. The preheated materials are then sequentially introduced into a microchannel reactor for reaction. This reaction does not require light or a catalyst, and the raw material conversion rate is over 99%, with a product selectivity of over 98%. Microchannel reactors can improve mass transfer and heat transfer performance and shorten reaction times, but solid materials cannot pass through the microchannels. If a large amount of solids is generated during the reaction, the microchannels are prone to clogging, making continuous production impossible. At the current technological level, industrialization of microchannel reactors is difficult.

[0007] CN104130100A discloses a method for producing chlorinated hydrocarbons by liquid-phase chlorination of 1,1,1,3-tetrachloropropane under the action of dissolved ferric chloride to produce 1,1,1,2,3-pentachloropropane, but the product selectivity is low and the catalyst is unstable, lasting only 5-6 hours.

[0008] As described above, conventional production technologies suffer from several major drawbacks. On the one hand, the catalyst is unstable. Currently, an anhydrous FeCl3 Lewis acid catalyst is widely used, but this catalyst is prone to deactivation and has problems with separation of the product and catalyst under liquid-phase conditions, making it useless for industrial production. On the other hand, trichloropropene, the raw material and intermediate used to produce 1,1,1,2,3-pentachloropropane, is prone to self-polymerization during the reaction, resulting in increased by-products and reduced product yields, and complicating subsequent separation and purification. Therefore, there is an urgent need to develop a safe, environmentally friendly method for producing 1,1,1,2,3-pentachloropropane that offers simple processes, good catalyst stability, high production efficiency, and high productivity. Summary of the Invention [Problem to be solved by the invention]

[0009] The object of the present invention is to provide a method for continuously producing 1,1,1,2,3-pentachloropropane, which has a simple process, good catalyst stability, high production efficiency, and is safe and environmentally friendly, in response to the shortcomings of the prior art. [Means for solving the problem]

[0010] To solve the above technical problems, the present invention provides the following technical solution: A continuous method for producing 1,1,1,2,3-pentachloropropane, in which 1,1,1,3-tetrachloropropane and chlorine gas are continuously introduced into a reactor and reacted under the action of a solid oxide catalyst to obtain 1,1,1,2,3-pentachloropropane.

[0011] Preferably, the reaction temperature is 50 to 100°C.

[0012] Preferably, the reaction pressure is 0.1 to 0.5 MPa.

[0013] Preferably, the molar ratio of the 1,1,1,3-tetrachloropropane to the chlorine gas fed is 0.8 to 1.1:1.

[0014] Preferably, the solid oxide catalyst is at least one of magnesium oxide, iron oxide, zinc oxide, aluminum oxide, silicon oxide, and titanium oxide.

[0015] Preferably, the chlorine gas is pretreated with the solid oxide catalyst before reaction.

[0016] Preferably, the pretreatment is carried out at a temperature of 60 to 200°C for 20 to 40 hours, and the space velocity of the chlorine gas is 50 to 100 h -1 is.

[0017] Preferably, the reactor is a trickle bed reactor.

[0018] Preferably, the 1,1,1,3-tetrachloropropane and chlorine gas flow cocurrently or countercurrently in the reactor.

[0019] The method for producing 1,1,1,2,3-pentachloropropane of the present invention uses 1,1,1,3-tetrachloropropane and chlorine gas as raw materials and produces 1,1,1,2,3-pentachloropropane through a single-stage reaction over a solid oxide catalyst. In actual production, the resulting product can be purified, as needed, by conventional techniques in this field, such as rectification, to obtain a higher-purity 1,1,1,2,3-pentachloropropane product. The method for producing 1,1,1,2,3-pentachloropropane of the present invention is a gas-liquid-solid three-phase reaction, and has the advantages of a simple process, mild reaction conditions, a high conversion rate of 1,1,1,3-tetrachloropropane, high product selectivity, stable catalytic performance, and the ability to produce continuously, making it highly suitable for industrial applications. In the present invention, the main chemical reactions are as follows:

[0020] Main reaction: [ka]

[0021] Side effects: [ka] [Effects of the Invention]

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] 1. Simple process. Using 1,1,1,3-tetrachloropropane and chlorine gas as raw materials, 1,1,1,2,3-pentachloropropane can be continuously produced through a one-stage reaction under the action of a solid oxide catalyst, significantly simplifying the production process. In addition, the oxide catalyst is a solid catalyst, and can be easily separated from the product after the reaction is completed, overcoming the drawback of the prior art that it is difficult to separate the catalyst from the product.

[0024] 2. The catalyst has good stability and high catalytic activity. The conversion rate of 1,1,1,3-tetrachloropropane is above 90.3%, and can reach a maximum of 98.4%. The selectivity of 1,1,1,2,3-pentachloropropane is above 93.1%, and can reach a maximum of 98.2%. There is no obvious decrease in catalytic activity even after continuous operation for more than 360 hours.

[0025] 3. Easy to commercialize: The present invention enables continuous production of 1,1,1,2,3-pentachloropropane through a single-stage reaction, and the catalyst used is low in production cost and easily available, making it easy to realize industrial mass production and showing promising future applications.

[0026] 4. Low investment: The present invention uses a gas-liquid-solid three-phase reaction with mild reaction conditions, which significantly reduces the number and cost of production equipment compared to the two-stage method, simplifies operation, and improves production safety. [Brief explanation of the drawings]

[0027] [Figure 1] FIG. 1 is a schematic diagram of the reaction modes of Examples 1 to 8 of the present invention. [Figure 2] FIG. 1 is a schematic diagram of the reaction mode in Example 9 of the present invention. [Figure 3] This is a chromatogram of the product obtained in Example 1 of the present invention. From this figure, it can be seen that this chromatogram has a stable baseline, few impurity peaks, and no tailing or overlapping of the main peaks, allowing for separation of the products and facilitating quantitative analysis. The peak at 13.227 min represents 1,1,1,3-tetrachloropropane, the peak at 14.226 min represents 1,1,2,3-tetrachloropropene, the peak at 16.323 min represents 1,1,1,2,3-pentachloropropane, and the peak at 18.811 min represents 1,1,1,2,2,3-hexachloropropane. DETAILED DESCRIPTION OF THE INVENTION

[0028] The following will clearly and completely describe the technical solutions of the present invention with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without performing creative work all fall within the protection scope of the present invention.

[0029] Example 1 120 mL of aluminum oxide catalyst was loaded into a trickle-bed reactor (length 50 cm, diameter 2.5 cm) and then heated for 60 h. -1 Chlorine gas was continuously introduced into the top of the trickle-bed reactor at a space velocity of 1000 kJ / s to pretreat the catalyst. The temperature of the trickle-bed reactor was controlled at 150°C and the pressure at 0.1 MPa. The pretreatment process was completed after 20 hours. After catalyst pretreatment was completed, the temperature was lowered to 70°C, and 1,1,1,3-tetrachloropropane (flow rate 60 g / h) and chlorine gas were continuously introduced into the top of the trickle-bed reactor to react. During the reaction, the molar ratio of 1,1,1,3-tetrachloropropane to chlorine gas was controlled at 1:1, and the pressure was controlled at 0.1 MPa. The reaction was continued for 24 hours, and the reaction product was collected after suction. Analysis of the reaction product by gas chromatography revealed a conversion of 1,1,1,3-tetrachloropropane of 93.9% and a selectivity for 1,1,1,2,3-pentachloropropane of 94.9%. After 360 hours of reaction, samples were taken and analyzed again, and it was found that the conversion rate of the raw material and the selectivity of the product did not decrease, indicating that the stability of this catalyst was good.

[0030] Example 2 120 mL of aluminum oxide catalyst was loaded into a trickle-bed reactor (length 50 cm, diameter 2.5 cm) and then heated for 50 h. -1Chlorine gas was continuously introduced into the top of the trickle-bed reactor at a space velocity of 1000 kJ / s to pretreat the catalyst. The temperature of the trickle-bed reactor was controlled at 120°C and the pressure at 0.1 MPa, and the pretreatment process was completed after 20 hours. After catalyst pretreatment was completed, the temperature was lowered to 70°C, and 1,1,1,3-tetrachloropropane (flow rate 60 g / h) and chlorine gas were continuously introduced into the top of the trickle-bed reactor to react. During the reaction, the molar ratio of 1,1,1,3-tetrachloropropane to chlorine gas was controlled at 1:1, and the pressure was controlled at 0.1 MPa. The reaction was continued for 24 hours, and the reaction product was collected after suction. Analysis of the reaction product by gas chromatography revealed a conversion of 1,1,1,3-tetrachloropropane of 91.8% and a selectivity for 1,1,1,2,3-pentachloropropane of 97.2%. After 360 hours of reaction, samples were taken and analyzed again, and it was found that the conversion rate of the raw material and the selectivity of the product did not decrease, indicating that the stability of this catalyst was good.

[0031] Example 3 120 mL of aluminum oxide catalyst was loaded into a trickle-bed reactor (length 50 cm, diameter 2.5 cm) and then heated for 50 h. -1 Chlorine gas was continuously introduced into the top of the trickle-bed reactor at a space velocity of 0.1 MPa to pretreat the catalyst. The temperature of the trickle-bed reactor was controlled at 200°C and the pressure at 0.1 MPa. The pretreatment process was completed after 25 hours. After catalyst pretreatment was completed, the temperature was lowered to 70°C, and 1,1,1,3-tetrachloropropane (flow rate 60 g / h) and chlorine gas were continuously introduced into the top of the trickle-bed reactor to react. During the reaction, the molar ratio of 1,1,1,3-tetrachloropropane to chlorine gas was controlled at 0.8:1 and the pressure at 0.2 MPa. The reaction was continued for 24 hours, and the reaction product was collected after suction. Analysis of the reaction product by gas chromatography revealed a conversion of 1,1,1,3-tetrachloropropane of 95.5% and a selectivity for 1,1,1,2,3-pentachloropropane of 94.3%. After 400 hours of reaction, samples were taken and analyzed again, and it was found that the conversion rate of the raw material and the selectivity of the product did not decrease, indicating that the stability of this catalyst was good.

[0032] Example 4 120 mL of aluminum oxide catalyst was loaded into a trickle-bed reactor (length 50 cm, diameter 2.5 cm) and then heated for 50 h. -1 Chlorine gas was continuously introduced into the top of the trickle-bed reactor at a space velocity of 0.1 MPa to pretreat the catalyst. The temperature of the trickle-bed reactor was controlled at 60°C and the pressure at 0.1 MPa. The pretreatment process was completed after 30 hours. After catalyst pretreatment was completed, the temperature was lowered to 50°C, and 1,1,1,3-tetrachloropropane (flow rate 60 g / h) and chlorine gas were continuously introduced into the top of the trickle-bed reactor to react. During the reaction, the molar ratio of 1,1,1,3-tetrachloropropane to chlorine gas was controlled at 0.8:1 and the pressure at 0.5 MPa. The reaction was continued for 24 hours, and the reaction product was collected after suction. Analysis of the reaction product by gas chromatography revealed a conversion of 1,1,1,3-tetrachloropropane of 92.3% and a selectivity for 1,1,1,2,3-pentachloropropane of 98.2%. After 480 hours of reaction, samples were taken and analyzed again, and it was found that the conversion rate of the raw material and the selectivity of the product did not decrease, indicating that the stability of this catalyst was good.

[0033] Example 5 120 mL of aluminum oxide catalyst was loaded into a trickle-bed reactor (length 50 cm, diameter 2.5 cm) and then heated for 80 h. -1Chlorine gas was continuously introduced into the top of the trickle-bed reactor at a space velocity of 1.0 sq. m / s to pretreat the catalyst. The temperature of the trickle-bed reactor was controlled at 150°C and the pressure at 0.1 MPa. The pretreatment process was completed after 20 hours. After catalyst pretreatment was completed, the temperature was lowered to 80°C, and 1,1,1,3-tetrachloropropane (flow rate 60 g / h) and chlorine gas were continuously introduced into the top of the trickle-bed reactor to react. During the reaction, the molar ratio of 1,1,1,3-tetrachloropropane to chlorine gas was controlled at 1.1:1 and the pressure at 0.1 MPa. The reaction was continued for 24 hours, and the reaction product was collected after suction. Analysis of the reaction product by gas chromatography revealed a conversion of 1,1,1,3-tetrachloropropane of 90.3% and a selectivity for 1,1,1,2,3-pentachloropropane of 97.5%. After 480 hours of reaction, samples were taken and analyzed again, and it was found that the conversion rate of the raw material and the selectivity of the product did not decrease, indicating that the stability of this catalyst was good.

[0034] Example 6 120 mL of aluminum oxide catalyst was loaded into a trickle-bed reactor (length 50 cm, diameter 2.5 cm) and then heated for 100 h. -1 Chlorine gas was continuously introduced into the top of the trickle-bed reactor at a space velocity of 0.1 MPa to pretreat the catalyst. The temperature of the trickle-bed reactor was controlled at 150°C and the pressure at 0.1 MPa. The pretreatment process was completed after 40 hours. After catalyst pretreatment was completed, the temperature was lowered to 100°C, and 1,1,1,3-tetrachloropropane (flow rate 60 g / h) and chlorine gas were continuously introduced into the top of the trickle-bed reactor to react. During the reaction, the molar ratio of 1,1,1,3-tetrachloropropane to chlorine gas was controlled at 0.8:1 and the pressure at 0.1 MPa. The reaction was continued for 24 hours, and the reaction product was collected after suction. Analysis of the reaction product by gas chromatography revealed a conversion of 1,1,1,3-tetrachloropropane of 98.4% and a selectivity for 1,1,1,2,3-pentachloropropane of 93.1%. After 480 hours of reaction, samples were taken and analyzed again, and it was found that the conversion rate of the raw material and the selectivity of the product did not decrease, indicating that the stability of this catalyst was good.

[0035] Example 7 120 mL of zinc oxide catalyst was loaded into a trickle-bed reactor (length 50 cm, diameter 2.5 cm) and then heated for 80 h. -1 Chlorine gas was continuously introduced into the top of the trickle-bed reactor at a space velocity of 1000 kJ / s to pretreat the catalyst. The temperature of the trickle-bed reactor was controlled at 120°C and the pressure at 0.1 MPa. The pretreatment process was completed after 20 hours. After catalyst pretreatment was completed, the temperature was lowered to 70°C, and 1,1,1,3-tetrachloropropane (flow rate 60 g / h) and chlorine gas were continuously introduced into the top of the trickle-bed reactor to react. During the reaction, the molar ratio of 1,1,1,3-tetrachloropropane to chlorine gas was controlled at 0.8:1 and the pressure at 0.1 MPa. The reaction was continued for 24 hours, and the reaction product was collected after suction. Analysis of the reaction product by gas chromatography revealed a conversion of 1,1,1,3-tetrachloropropane of 92.4% and a selectivity for 1,1,1,2,3-pentachloropropane of 95.7%. After 600 hours of reaction, samples were taken and analyzed again, and it was found that the conversion rate of the raw material and the selectivity of the product did not decrease, indicating that the stability of this catalyst was good.

[0036] Example 8 120 mL of magnesium oxide catalyst was loaded into a trickle-bed reactor (length 50 cm, diameter 2.5 cm) and then heated for 50 h. -1Chlorine gas was continuously introduced into the top of the trickle-bed reactor at a space velocity of 1000 kJ / s to pretreat the catalyst. The temperature of the trickle-bed reactor was controlled at 120°C and the pressure at 0.1 MPa, and the pretreatment process was completed after 30 hours. After catalyst pretreatment was completed, the temperature was lowered to 70°C, and 1,1,1,3-tetrachloropropane (flow rate 60 g / h) and chlorine gas were continuously introduced into the top of the trickle-bed reactor to react. During the reaction, the molar ratio of 1,1,1,3-tetrachloropropane to chlorine gas was controlled at 0.8:1 and the pressure at 0.1 MPa. The reaction was continued for 24 hours, and the reaction product was collected after suction. Analysis of the reaction product by gas chromatography revealed a conversion of 1,1,1,3-tetrachloropropane of 95.5% and a selectivity for 1,1,1,2,3-pentachloropropane of 94.2%. After 600 hours of reaction, samples were taken and analyzed again, and it was found that the conversion rate of the raw material and the selectivity of the product did not decrease, indicating that the stability of this catalyst was good.

[0037] Example 9 120 mL of aluminum oxide catalyst was loaded into a trickle-bed reactor (length 50 cm, diameter 2.5 cm) and then heated for 50 h. -1Chlorine gas was continuously introduced from the bottom of the trickle-bed reactor at a space velocity of 1000 kJ / s to pretreat the catalyst. The temperature of the trickle-bed reactor was controlled at 150°C and the pressure at 0.1 MPa. This was maintained for 20 hours, completing the pretreatment process. After catalyst pretreatment was complete, the temperature was lowered to 70°C, and 1,1,1,3-tetrachloropropane (flow rate 60 g / h) was continuously introduced from the top of the trickle-bed reactor, while chlorine gas was continuously introduced from the bottom of the trickle-bed reactor. During the reaction, the molar ratio of 1,1,1,3-tetrachloropropane to chlorine gas was controlled at 1:1, and the pressure was controlled at 0.1 MPa. The reaction was continued for 24 hours, and the reaction product was collected after suction. Analysis of the reaction product by gas chromatography revealed a conversion of 1,1,1,3-tetrachloropropane of 95.2% and a selectivity for 1,1,1,2,3-pentachloropropane of 93.8%. After 720 hours of reaction, samples were taken and analyzed again, which showed that the conversion rate of the raw material and the selectivity of the product did not decrease, indicating that the stability of this catalyst was good.

[0038] It should be noted that the above is merely a preferred embodiment of the present invention, and those skilled in the art may make further improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered as within the scope of protection of the present invention.

Claims

1. 1,1,1,3-tetrachloropropane and chlorine gas are successively introduced into a reactor and reacted under the action of a solid oxide catalyst to obtain 1,1,1,2,3-pentachloropropane; Among the solid oxide catalysts, aluminum oxide, magnesium oxide, and zinc oxide pretreated with chlorine gas are used, The solid oxide catalyst is at least one of aluminum oxide, magnesium oxide, and zinc oxide. A method for continuously producing 1,1,1,2,3-pentachloropropane.

2. 2. The method for continuously producing 1,1,1,2,3-pentachloropropane according to claim 1, wherein the reaction temperature is 50 to 100°C.

3. 2. The method for continuously producing 1,1,1,2,3-pentachloropropane according to claim 1, wherein the reaction pressure is 0.1 to 0.5 MPa.

4. 2. The method for continuously producing 1,1,1,2,3-pentachloropropane according to claim 1, wherein the molar ratio of the 1,1,1,3-tetrachloropropane to the chlorine gas fed is 0.8 to 1.1:

1.

5. 2. The method for continuously producing 1,1,1,2,3-pentachloropropane according to claim 1, wherein the solid oxide catalyst is pretreated with chlorine gas before the reaction.

6. The pretreatment is carried out at a temperature of 60 to 200°C for 20 to 40 hours, and at a space velocity of 50 to 100 h －１ The method for continuously producing 1,1,1,2,3-pentachloropropane according to claim 5,

7. 2. The method for continuously producing 1,1,1,2,3-pentachloropropane according to claim 1, wherein the reactor is a trickle-bed reactor.

8. 2. The method for continuously producing 1,1,1,2,3-pentachloropropane according to claim 1, wherein the 1,1,1,3-tetrachloropropane and chlorine gas flow in a cocurrent or countercurrent manner in the reactor.

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