A production process, apparatus, and application for the co-production of 3-chloropropene and dichloropropanol

Abstract

The application provides a production process and device and application thereof for co-production of 3-chloropropylene and dichloropropanol, comprising: allowing raw materials of propylene and chlorine to occur halogenation reaction in a halogenation reactor, and allowing the halogenation reaction product to enter a heat exchanger, and after heat exchange, the halogenation reaction product is divided into a gas phase part and a liquid phase part, wherein hydrogen chloride gas in the gas phase part is used as raw material to occur hydrochlorination reaction with glycerol and a catalyst in a hydrochlorination reactor, and is used for preparing dichloropropanol; and the liquid phase part enters a rectifying column to separate and purify to obtain 3-chloropropylene, the application fully utilizes a large amount of hydrogen chloride by-produced in a high-temperature chlorination process of propylene, and supplies a chlorine source required in a glycerol hydrochlorination process, so that a by-production recovery treatment process in the high-temperature chlorination process of propylene is omitted, a production process is simplified, energy consumption is reduced, the device is simple to operate, equipment production efficiency is high, and industrial application is facilitated.

Description

Technical Field

[0001] This application relates to the field of epichlorohydrin production technology, specifically to a production process, apparatus, and application for the co-production of 3-chloropropene and dichloropropanol. Background Technology

[0002] Epichlorohydrin (ECH), also known as epichlorohydrin or 3-chloro-1,2-epoxypropane, is a colorless liquid, insoluble in water, and moderately toxic. It is an important raw material for the production of epoxy resins, the synthesis of glycerol and chlorohydrin rubber, and can also be used to prepare other derivatives. It can also be used as a solvent, plasticizer, flame retardant, and surfactant. It is an important organic chemical raw material and a key intermediate in the petrochemical industry, with a wide range of applications.

[0003] Currently, the hydrogen peroxide method is commonly used in the production of epichlorohydrin, which is prepared by the direct epoxidation of the raw material 3-chloropropene. This raw material 3-chloropropene is generated by the halogenation reaction of propylene and chlorine. Although this method solves the problems of saponification wastewater and waste residue generated in the chlorohydrin reaction and alkali saponification process in the original high-temperature chlorination method and glycerol saponification process, and the production process is simple, a large amount of hydrogen chloride is generated as a byproduct during production, which requires further treatment, resulting in high production costs and complex treatment processes. Summary of the Invention

[0004] In view of this, this application provides a co-production process and apparatus for 3-chloropropene and dichloropropanol, which solves the technical problem in the prior art that hydrogen chloride, a byproduct generated during the production of epichlorohydrin, needs further treatment, resulting in high production costs.

[0005] This application provides a production process for the co-production of 3-chloropropene and dichloropropanol, characterized by comprising: halogenating raw materials propylene and chlorine in a halogenation reactor, wherein the product of the halogenation reaction is a mixture of 3-chloropropene, hydrogen chloride, and other halogenation byproducts; the halogenation reaction product is separated into a gas phase and a liquid phase after heat exchange, wherein the gas phase is a mixture of unreacted propylene and the reaction product hydrogen chloride, and the hydrogen chloride gas in the gas phase is used as a raw material to undergo a hydrochlorination reaction with glycerol and a catalyst in a hydrochlorination reactor to prepare dichloropropanol; the liquid phase is a mixture of 3-chloropropene and byproducts with boiling points higher than 3-chloropropene, and the liquid phase enters a distillation column for separation and purification to obtain 3-chloropropene.

[0006] In one possible implementation, the non-condensable gas extracted from the top of the hydrochlorination reactor is condensed and absorbed, and the treated propylene is used again as a feedstock for the halogenation reaction.

[0007] In one possible implementation, the hydrochlorination product liquid collected from the bottom of the hydrochlorination reactor is purified and separated. Pure dichloropropanol product is collected at 174-185°C. The separated catalyst and unreacted glycerol are recycled back to the hydrochlorination reactor. The purified and separated light components are collected with acidic waste liquid after condensation and absorption treatment, and the purified and separated heavy components are collected and processed. The hydrochlorination product liquid includes 1,3-dichloro-2-propanol, 2,3-dichloro-1-propanol, catalyst, water, and a small amount of unreacted glycerol, as well as by-products such as glyceryl esters and chloropropanediol esters. The heavy components include one or more of water, glyceryl monoesters, chloropropanediol monoesters, diglyceryl monoesters, glyceryl dimers, and glyceryl dimer esters. The light components include a small amount of water and hydrogen chloride.

[0008] In one possible implementation, the raw material propylene and raw material chlorine are preheated before being mixed to undergo a halogenation reaction; preferably, the preheating temperature of the raw material propylene is 350–510°C, and / or the preheating temperature of the raw material chlorine is 350–510°C.

[0009] In one possible implementation, propylene and chlorine, after being preheated, undergo a halogenation reaction in a halogenation reactor; wherein the molar ratio of propylene to chlorine entering the halogenation reactor is (1.5 to 30):1, and preferably, the reaction temperature of the halogenation reaction is greater than 500°C.

[0010] In one possible implementation, the glycerol and hydrogen chloride are introduced into a hydrochlorination reactor at a molar ratio of (0.05 to 0.5):1 to undergo a hydrochlorination reaction; preferably, the catalyst is an organic acid, more preferably, the catalyst is one or more of anhydrous acetic acid, hexanoic acid, octanoic acid, and adipic acid; preferably, the reaction temperature of the hydrochlorination reaction is 80-130°C.

[0011] In one possible implementation, the liquid phase of the halogenation reaction product after heat exchange is purified by distillation in a distillation column to obtain 3-chloropropene; wherein, a light halogenated hydrocarbon with a boiling point lower than 3-chloropropene is collected from the top of the distillation column, and DD mixture is collected from the bottom of the distillation column.

[0012] According to a second aspect of this application, an apparatus for the co-production of 3-chloropropene and dichloropropanol is provided. This apparatus is capable of being used in the aforementioned production process for the co-production of 3-chloropropene and dichloropropanol. The apparatus includes: a halogenated reactor; a heat exchanger connected to the halogenated reactor, with a gas phase outlet pipe connected to the top of the heat exchanger and a crude chloropropene outlet pipe connected to the bottom of the heat exchanger; and a distillation column, with the crude chloropropene outlet pipe connected to the inlet of the distillation column, a light halogenated hydrocarbon outlet pipe connected to the top of the distillation column, and a DD mixture outlet pipe connected to the bottom of the distillation column. The distillation column is connected to a 3-chloropropene outlet pipeline; a hydrochlorination reactor, which is connected to the heat exchanger via the gas phase outlet pipeline, and is also connected to a glycerol inlet pipeline and a catalyst inlet pipeline, with a non-condensable gas outlet pipeline connected to the top of the hydrochlorination reactor and a hydrochlorinated product liquid outlet pipeline connected to the bottom of the hydrochlorination reactor; and a refining unit, which is connected to the hydrochlorination reactor via the hydrochlorinated product liquid outlet pipeline, with a light component outlet pipeline connected to the top of the refining unit and a heavy component outlet pipeline connected to the bottom of the refining unit.

[0013] The condenser absorber is connected to the refining unit via a light component extraction pipeline, and to the hydrochlorination reactor via a hydrochlorination non-condensable gas extraction pipeline. The condenser absorber is also connected to a circulating propylene pipeline and an acidic waste liquid extraction pipeline.

[0014] In one possible implementation, the apparatus for co-producing 3-chloropropylene and dichloropropanol further includes: a propylene preheater connected to a propylene inlet pipe, the propylene preheater being connected to the condenser absorber via the circulating propylene pipe; and a chlorine preheater connected to a chlorine inlet pipe; wherein the propylene preheater and the chlorine preheater are respectively connected to the halogenated reactor.

[0015] According to a third aspect of this application, this application provides a process for producing epichlorohydrin, the process comprising the aforementioned process for co-producing 3-chloropropene and dichloropropanol; and / or the production apparatus used in the process for producing epichlorohydrin comprises the aforementioned apparatus for co-producing 3-chloropropene and dichloropropanol.

[0016] This application provides a production process and apparatus for the co-production of 3-chloropropene and dichloropropanol. Propylene and chlorine undergo a halogenation reaction in a halogenation reactor. The product of the halogenation reaction is a mixture of 3-chloropropene, hydrogen chloride, and other halogenation byproducts. After heat exchange, the halogenation reaction product is divided into a gas phase and a liquid phase. The gas phase consists of a mixture of unreacted propylene and the reaction product hydrogen chloride. The hydrogen chloride gas in the gas phase is used as a raw material to undergo a hydrochlorination reaction with glycerol and a catalyst in a hydrochlorination reactor to prepare dichloropropanol. The liquid phase is a mixture of 3-chloropropene and byproducts with boiling points higher than 3-chloropropene. The liquid phase enters a distillation column for separation and purification to obtain 3-chloropropene. This application uses hydrogen chloride, a byproduct of the high-temperature chlorination of propylene to produce allyl chloride, as the source of hydrogen chloride in the hydrochlorination of glycerol. Hydrochloric acid gas containing propylene is introduced into the hydrochlorination reactor along with glycerol and a catalyst for a substitution reaction. After the hydrochloric acid gas is consumed, the remaining non-condensable gas (mainly propylene) is purified and reintroduced into the high-temperature chlorination reactor of propylene. This device combines two methods for producing epichlorohydrin: the glycerol method and the hydrogen peroxide method. It solves the problem of treating chlorine-containing waste such as hydrogen chloride generated during the hydrogen peroxide method and also solves the problem of raw materials required for the glycerol method. It not only eliminates the by-product recovery and treatment process during the high-temperature chlorination of propylene, simplifying the production process and reducing energy consumption, but also allows for the sharing of utilities, separation units, and epichlorohydrin product tanks. This co-production device is simple to operate, has high production efficiency, and is conducive to industrial application. Attached Figure Description

[0017] Figure 1 The diagram shown is a structural schematic of a device for co-producing chloropropylene and dichloropropanol provided in this application.

[0018] Explanation of reference numerals in the attached figures:

[0019] 1. Propylene; 2. Chlorine; 3. Propylene preheater; 4. Chlorine preheater; 5. Halogenation reactor; 6. Heat exchanger; 7. Liquid phase section; 8. Gas phase section; 9. Distillation column; 10. Glycerol; 11. Catalyst; 12. Hydrochlorination reactor; 13. Non-condensable gas; 14. Hydrochlorination product liquid; 15. Condensation absorber; 16. Refining unit; 17. Recycled propylene; 18. Light halogenated hydrocarbons; 19. DD mixture; 20. 3-chloropropene; 21. Dichloropropanol; 22. Recycled catalyst; 23. Heavy components; 24. Acidic waste liquid; 25. Light components. Detailed Implementation

[0020] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0021] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0022] The main raw materials for producing epichlorohydrin via the glycerol chlorination saponification method are industrial glycerol, 30% caustic soda, and gaseous hydrogen chloride. The process involves four steps: the hydrochlorination of glycerol to produce 1,3-dichloro-2-propanol and 2,3-dichloro-1-propanol; the separation of dichloropropanol; the saponification of dichloropropanol; and the refining of epichlorohydrin. This method is characterized by its simple production process, short flow, low emissions of waste, low investment, low operating costs, and renewable raw materials. The glycerol method has increased its share of total production from 10% to approximately 39% currently, but its production process involves the use of hydrogen chloride. The hydrogen peroxide method for producing epichlorohydrin involves the direct epoxidation of 3-chloropropene to prepare epichlorohydrin. The raw material is 3-chloropropene, which is produced by the halogenation reaction of propylene and chlorine. This method completely solves the problems of saponification wastewater and residue generated in the chlorohydrin reaction and alkali saponification process of the original allyl chloride process. The production process is simple, but a large amount of hydrogen chloride is generated as a byproduct that needs further treatment. If 3-chloropropene is produced separately using the existing production process, 0.48 tons of hydrogen chloride gas are generated as a byproduct for every ton of 3-chloropropene produced, which in turn generates about 2 tons of 25% hydrochloric acid solution. The byproduct hydrogen chloride gas carries away a large amount of heat and is absorbed to become hydrochloric acid. The dissolution of hydrogen chloride gas, the generation and treatment of hydrochloric acid, and the storage process need to be considered separately. On the other hand, the existing glycerol process for producing dichloropropanol consumes a large amount of hydrogen chloride and requires 5 to 6 tons of steam per ton.

[0023] Therefore, this application provides a production process and apparatus for the co-production of 3-chloropropene and dichloropropanol. Hydrogen chloride, a byproduct of the high-temperature chlorination of propylene to produce chloropropene, is used as the source of hydrogen chloride in the hydrochlorination of glycerol. Hydrogen chloride, along with glycerol and a catalyst, enters the hydrochlorination reactor for a substitution reaction. After the hydrogen chloride is consumed, the remaining non-condensable gas (mainly propylene) is purified and used again as a feedstock for the halogenation reaction. This co-production apparatus can simultaneously produce chloropropene and dichloropropanol. The front section is used for the hydrogen peroxide method to produce epichlorohydrin; the back section is used for the glycerol method to produce epichlorohydrin. The two processes are combined to produce epichlorohydrin. The combination of propane production methods and equipment solves the problem of treating chlorine-containing waste such as hydrogen chloride generated during the hydrogen peroxide process, and also solves the problem of hydrogen chloride raw material required for glycerol production. It not only eliminates the by-product recovery and treatment process during the high-temperature chlorination of propylene, simplifying the production process and reducing energy consumption, but also allows for the sharing of utilities, separation units, and epichlorohydrin product tanks. It effectively utilizes the hydrogen chloride generated during the high-temperature chlorination of propylene, significantly improving the utilization efficiency of chlorine, reducing the generation of chlorine-containing waste, thereby reducing the generation and treatment of waste strong acid, and ultimately reducing production costs.

[0024] The chloropropene unit and the dichloropropanol unit can share utilities, separation units, and epichlorohydrin product tanks. Specifically, hot steam can be first supplied to units and equipment requiring higher temperatures, such as halogenation reactors, propylene preheaters, and chlorine preheaters. After one heat exchange, the remaining steam can be used to heat the glycerol hydrochlorination reactor. Nitrogen protection pipelines and emergency pipelines can be shared. 3-chloropropene can be used for epoxidation to produce epichlorohydrin, and dichloropropanol can also be used for saponification to produce epichlorohydrin. The crude epichlorohydrin product after preliminary separation can share the distillation and purification unit, and the purified epichlorohydrin product tanks can also be shared.

[0025] Figure 1 The diagram shown is a structural schematic of a device for the co-production of 3-chloropropene and dichloropropanol provided in this application. It is used as an example for illustration. Figure 1 The present invention describes the production process and apparatus for the co-production of 3-chloropropene and dichloropropanol. For example... Figure 1 As shown, propylene 1 enters the propylene preheater 3 through the propylene inlet, and the temperature of the propylene preheater 3 is 350-510℃. Chlorine 2 enters the chlorine preheater 4 through the chlorine inlet, and the temperature of the chlorine preheater 4 is 350-510℃. After preheating, propylene 1 and chlorine 2 enter the halogenation reactor 5 in a molar ratio of (1.5-30):1. At a temperature above 500℃, propylene 1 and chlorine 2 undergo a halogenation reaction to obtain a mixture of propylene, 3-chloropropene, hydrogen chloride, and other halogenation byproducts (including 1-chloropropane, 2-chloropropane, 1-chloropropene, 1,2-dichloropropane, 1,3-dichloropropane, 1,2-dichloropropene, 1,3-dichloropropene, etc.).

[0026] A mixture of propylene, 3-chloropropene, hydrogen chloride, and other halogenated byproducts enters heat exchanger 6. After heat exchange, the temperature drops from 500°C at the outlet of halogenated reactor 5 to below 35°C. At this point, the mixture separates into two phases: a liquid phase and a gas phase. The liquid phase is collected from the bottom of heat exchanger 6. This liquid phase is a mixed solution of 3-chloropropene and byproducts with boiling points higher than 3-chloropropene (including two types of dichloropropane and two types of dichloropropene, and a small amount of monochloropropane, etc.). The liquid phase collected from the bottom of heat exchanger 6 enters distillation column 9 for separation and purification to obtain the 3-chloropropene product. The light component, consisting of a small amount of light halogenated hydrocarbons with boiling points lower than 3-chloropropene, is collected from the top of distillation column 9. The heavy component, consisting of a polyhalogenated hydrocarbon DD mixture (a mixture of 1,2-dichloropropane and 1,3-dichloropropene), is collected from the bottom of distillation column 9. The gas phase 8 is collected from the top of heat exchanger 6. The gas phase 8 is a mixture of the remaining unreacted propylene and hydrogen chloride.

[0027] Glycerol and hydrogen chloride 10 are introduced into the hydrochlorination reactor 12 at a molar ratio of (0.05-0.5):1 along with catalyst 11 (the catalyst is a common organic acid, such as anhydrous acetic acid, hexanoic acid, octanoic acid, adipic acid, etc.). The hydrochlorination reaction occurs at 80-130℃, consuming glycerol and hydrogen chloride to produce two main products: 1,3-dichloro-2-propanol and 2,3-dichloro-1-propanol. The remaining non-condensable gas 13 after the reaction (including propylene that does not participate in the reaction and some hydrogen chloride) is collected from the top of the hydrochlorination reactor 12. After passing through the condenser absorber 15 to remove the remaining hydrogen chloride, halogenated hydrocarbons and water, propylene 17 is obtained. Propylene 17 is recycled back to the propylene preheater 3 and enters the halogenation reactor 5 together with fresh propylene to continue the propylene halogenation reaction. The acidic waste liquid 24 containing a small amount of halogenated hydrocarbons is discharged from the bottom of the condenser absorber 15 and sent to the waste liquid treatment workshop for treatment.

[0028] The hydrochlorination product liquid 14, after reaction in the hydrochlorination reactor 12, is collected from the bottom of the reactor. The hydrochlorination product liquid 14 contains two main products, 1,3-dichloro-2-propanol and 2,3-dichloro-1-propanol, as well as an organic acid catalyst, water, a small amount of unreacted glycerol, and byproducts of glyceryl esters and chloropropanediol esters, namely glyceryl monoesters, chloropropanediol monoesters, diglyceryl monoesters, glyceryl dimers, and glyceryl dimer esters. These are then purified in the purification unit 16. The product, pure dichloropropanol 21, is collected at 174-185℃, and excess organic acid catalyst and unreacted glycerol are separated and refluxed to the hydrochlorination reactor 12 through the catalyst inlet 11. The heavy components (water, glycerol esters, and chloropropanediol esters) collected from the bottom of the refining unit 16 are sent to the waste liquid treatment workshop for processing; a small amount of light components (small amount of water and hydrogen chloride) are collected from the top of the refining unit 16. The light components are condensed by the condenser absorber 15 and sent to the waste liquid treatment workshop with the acidic waste liquid 24.

[0029] In halogenation reactor 5, propylene should be kept in excess to prevent excessive chlorine, which could cause corrosion of the reactor. Unused propylene and byproduct hydrogen chloride mixture directly enters hydrochlorination reactor 12 as a source of hydrogen chloride to produce dichloropropanol through glycerol hydrochlorination. The reaction continues, and after removing the remaining small amount of hydrogen chloride, halogenated hydrocarbons, and water from the propylene mixture, it is dried before entering halogenation reactor 5 to participate in the halogenation reaction, ultimately achieving the co-production process of 3-chloropropene-dichloropropanol. This co-production unit fully utilizes the large amount of hydrogen chloride produced as a byproduct during the high-temperature chlorination of propylene to supply the chlorine source required for the hydrochlorination of glycerol, thereby eliminating the need for byproduct recovery and treatment during the high-temperature chlorination of propylene, simplifying the production process, reducing energy consumption, simplifying operation, and providing high equipment efficiency, which is conducive to industrial application.

[0030] Example 1

[0031] Propylene, the raw material, enters the propylene preheater 3 through the propylene inlet, where it vaporizes at 510°C. Chlorine, the raw material, enters the chlorine preheater 4 through the chlorine inlet, where it also vaporizes at 510°C. The vaporized propylene and vaporized chlorine 2 enter the halogenation reactor 5 at a molar ratio of 5:1 to undergo a halogenation reaction. During this reaction, propylene generates free radicals, and chlorine is converted into chlorine free radicals. Collisions between these free radicals lead to chlorination of the propylene at temperatures above 500°C, producing propylene, 3-chloropropene, hydrogen chloride, and other halogenated compounds. Other halogenated byproducts include 1-chloropropane, 2-chloropropane, 1-chloropropene, 1,2-dichloropropane, 1,3-dichloropropane, 1,2-dichloropropene, 1,3-dichloropropene, etc. Propylene, 3-chloropropene, hydrogen chloride and other byproducts enter heat exchanger 6 for heat exchange treatment. After heat exchange treatment, the temperature drops from 500℃ at the outlet of the halogenated reactor to below 35℃. At this time, the mixed gas is separated into gas and liquid phases. The liquid phase component is taken out from the bottom of the heat exchanger and the gas phase component is taken out from the top of the heat exchanger.

[0032] The gas phase component consists of a mixture of unreacted propylene and hydrogen chloride from the halogenation reactor. The feedstock, glycerol, and hydrogen chloride are introduced into the hydrochlorination reactor at a molar ratio of 0.275:1. The catalyst (anhydrous acetic acid) content is 6.67% (w / w). Under the action of the catalyst, the glycerol feedstock and hydrogen chloride undergo hydrochlorination at 107.6°C to produce hydrochlorinated product liquid 14. Hydrochlorinated product liquid 14 includes two main products, 1,3-dichloro-2-propanol and 2,3-dichloro-1-propanol, as well as an organic acid catalyst, water, a small amount of unreacted glycerol, and byproducts such as glyceryl esters and chloropropanediol esters, i.e., glycerol. Monoesters, chloropropanediol monoesters, diglycerides, glycerol dimers, and glycerol dimer esters, etc., the hydrochlorinated product liquid 14 enters the refining unit, where it is further refined at 180°C to produce pure dichloropropanol and separates excess organic acid catalyst. The organic acid catalyst is recycled back to the hydrochlorination reactor to participate in the hydrochlorination reaction again. The heavy phase waste liquid (water and organic compounds such as glycerides and chloropropanediol esters) collected from the bottom of the refining unit is sent to the waste liquid treatment workshop. The light component (a small amount of water and hydrogen chloride) collected from the top of the refining unit is condensed in the condenser and then sent to the waste liquid treatment workshop for further treatment along with the acidic waste liquid.

[0033] The liquid phase component collected from the bottom of the heat exchanger enters the distillation column 9 for separation and purification to obtain 3-chloropropene product. The light component collected from the top of the distillation column 9 is a small amount of light halogenated hydrocarbons with a boiling point lower than 3-chloropropene. The heavy component collected from the bottom of the distillation column 9 is a mixture of polyhalogenated hydrocarbons (DD) (a mixture of 1,2-dichloropropane and 1,3-dichloropropene).

[0034] Using the production process of Example 1, the selectivity for 3-chloropropene was 85.10%, and the selectivity for dichloropropanol was 88.20%.

[0035] Example 2

[0036] The implementation method of Example 2 is the same as that of Example 1, except that:

[0037] Propylene and chlorine are vaporized at 355°C. Propylene and chlorine are fed into a halogenation reactor at a molar ratio of 1.75:1. The halogenation reaction is carried out at 485°C. After heat exchange treatment, glycerol and hydrogen chloride are fed into a hydrochlorination reactor at a molar ratio of 0.338:1. The catalyst added to the hydrochlorination reactor has a content of 4.17% (w / w). The hydrochlorination reaction is carried out at 93.2°C. Excess propylene is dehydrochlorinated, dehydrated, and dehydrohalogenated, and then recycled back into the halogenation reactor. Crude 3-chloropropene and crude dichloropropanol are separated and purified to obtain 3-chloropropene and dichloropropanol products.

[0038] Using the production process of Example 2, the selectivity for 3-chloropropene was 64.03%, and the selectivity for dichloropropanol was 72.11%.

[0039] Example 3

[0040] The implementation method of Example 3 is the same as that of Example 1, except that:

[0041] Propylene and chlorine are vaporized at 433°C. Propylene and chlorine are fed into a halogenation reactor at a molar ratio of 3.5:1. The halogenation reaction is carried out at 493°C. After heat exchange treatment, glycerol and hydrogen chloride are fed into a hydrochlorination reactor at a molar ratio of 0.109:1. The catalyst added to the hydrochlorination reactor has a content of 2.35% (w / w). The hydrochlorination reaction is carried out at 86.5°C. Excess propylene is dehydrochlorinated, dehydrated, and dehydrohalogenated, and then recycled back into the halogenation reactor. Crude 3-chloropropene and crude dichloropropanol are separated and purified to obtain 3-chloropropene and dichloropropanol products.

[0042] Using the production process of Example 3, the selectivity for 3-chloropropene was 76.78%, and the selectivity for dichloropropanol was 40.22%.

[0043] Example 4

[0044] The implementation method of Example 4 is the same as that of Example 1, except that:

[0045] Propylene and chlorine are vaporized at 387°C. Propylene and chlorine are fed into a halogenation reactor at a molar ratio of 4.15:1. The halogenation reaction is carried out at 501°C. After heat exchange treatment, glycerol and hydrogen chloride are fed into a hydrochlorination reactor at a molar ratio of 0.461:1. The catalyst content added to the hydrochlorination reactor is 8.15% (w / w). The hydrochlorination reaction is carried out at 113.3°C. Excess propylene is dehydrochlorinated, dehydrated, and dehalogenated, and then recycled back into the halogenation reactor. Crude 3-chloropropene and crude dichloropropanol are separated and purified to obtain 3-chloropropene and dichloropropanol products.

[0046] Using the production process of Example 4, the selectivity for 3-chloropropene was 88.25%, and the selectivity for dichloropropanol was 87.08%.

[0047] Example 5

[0048] The implementation method of Example 5 is the same as that of Example 1, except that:

[0049] Propylene and chlorine are vaporized at 455°C. Propylene and chlorine are fed into a halogenation reactor at a molar ratio of 28.75:1. The halogenation reaction is carried out at 501°C. After heat exchange treatment, glycerol and hydrogen chloride are fed into a hydrochlorination reactor at a molar ratio of 0.461:1. The catalyst added to the hydrochlorination reactor has a content of 8.15% (w / w). The hydrochlorination reaction is carried out at 100.4°C. Excess propylene is dehydrochlorinated, dehydrated, and dehydrohalogenated, and then recycled back into the halogenation reactor. Crude 3-chloropropene and crude dichloropropanol are separated and purified to obtain 3-chloropropene and dichloropropanol products.

[0050] Using the production process of Example 4, the selectivity for 3-chloropropene was 88.25%, and the selectivity for dichloropropanol was 87.08%.

[0051] Table 1. Comparison of selectivity of 3-chloropropene and dichloropropanol in Examples 1-5

[0052]

[0053]

[0054] As shown in Table 1, when the vaporization temperature of propylene and chlorine in the preheater is 387℃, the molar ratio of propylene to chlorine entering the halogenation reactor is 4.15:1, the hydrochlorination reaction temperature is 113.3℃, ​​the molar ratio of glycerol to hydrogen chloride entering the hydrochlorination reactor is 0.461:1, and the catalyst content added to the hydrochlorination reactor is 8.15w / w, the selectivity of 3-chloropropene and dichloropropanol is the highest. The selectivity is the proportion of all products in the halogenation reaction of propylene chloride and the proportion of all products in the hydrochlorination reaction of dichloropropanol.

[0055] The hydrochlorination reaction temperature in Example 3 was lower than that in Example 4, and the amount of catalyst added was also lower than that in Example 4. The selectivity of 3-chloropropene and dichloropropanol in Example 3 was lower than that in Example 4.

[0056] The temperature of the hydrochlorination reaction in Example 2 was slightly higher than that in Example 3, and the amount of catalyst added was also slightly higher than that in Example 3. Therefore, the selectivity of 3-chloropropene and dichloropropene in Example 2 was slightly higher than that in Example 3.

[0057] In Example 1, the vaporization temperature of propylene and chlorine was 510°C, the molar ratio of propylene to chlorine entering the halogenation reactor was 5:1, and the molar ratio of glycerol to hydrogen chloride entering the hydrochlorination reactor was 0.275:1. The selectivity of 3-chloropropene and dichloropropanol was comparable to that in Example 4.

[0058] In Example 5, the molar ratio of propylene to chlorine was 28.75:1. The larger molar ratio increased the selectivity of chloropropylene, but required heating a large amount of unreacted propylene and produced a small amount of hydrochloric acid gas. In the subsequent hydrochlorination reaction, the amount of hydrogen chloride obtained was small, and the product was mainly monochloropropanediol, with very low selectivity for dichloropropanol.

[0059] Therefore, the molar ratio of propylene halogenation and the preheating temperature directly affect the selectivity of 3-chloropropene; while the molar ratio of glycerol to hydrogen chloride entering the hydrochlorination reactor and the amount of catalyst added to the hydrochlorination reactor directly affect the selectivity of dichloropropanol.

[0060] In this application, the amount of propylene introduced should be kept in excess to avoid corrosion of the hydrochlorination reactor by excessive chlorine gas. This can significantly improve the utilization efficiency of chlorine, reduce the generation of chlorine-containing waste, thereby reducing the generation and treatment of waste strong acid, and thus reducing production costs. The large amount of hydrogen chloride produced as a byproduct during the high-temperature chlorination of propylene is fully utilized to supply the chlorine source required for the hydrochlorination of glycerol, thereby eliminating the byproduct recovery and treatment process during the high-temperature chlorination of propylene, simplifying the production process and reducing energy consumption.

[0061] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications or equivalent substitutions made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A production process for the co-production of 3-chloropropene and dichloropropanol, characterized in that, The method comprises the following steps: The raw material propylene and chlorine gas are mixed after preheating and then halogenated in a halogenation reactor, and the halogenation product is a mixed gas of 3-chloropropylene, hydrogen chloride and other halogenated byproducts; the raw material propylene is preheated in a propylene preheater, and the raw material chlorine gas is preheated in a chlorine gas preheater; The halogenation reactor is connected with a heat exchanger, and the top of the heat exchanger is connected with a gas phase part extraction pipeline; The halogenation product is divided into a gas phase part and a liquid phase part after heat exchange, wherein the gas phase part is a mixed gas of unreacted propylene and reaction product hydrogen chloride, and the hydrogen chloride gas in the gas phase part is used as raw material to react with glycerol and a catalyst in a hydrochlorination reactor to prepare dichloropropanol, and the obtained product dichloropropanol is used to produce epichlorohydrin by the glycerol method; the liquid phase part is a mixed liquid of 3-chloropropylene and byproducts with a boiling point higher than that of 3-chloropropylene, and the liquid phase part is separated and purified in a rectifying column to obtain 3-chloropropylene, and the obtained product 3-chloropropylene is used to produce epichlorohydrin by the hydrogen peroxide method; The hydrochlorination reactor is connected with the heat exchanger through the gas phase part extraction pipeline; The non-condensable gas extracted from the top of the hydrochlorination reactor after the gas phase part is subjected to hydrochlorination is condensed and absorbed in a condensation absorber, and the treated propylene is used as raw material for halogenation again; The hydrochlorination product liquid extracted from the bottom of the hydrochlorination reactor is refined and separated, the separated catalyst and unreacted glycerol are circulated to the hydrochlorination reactor, the light component after refined separation is treated by condensation and absorption in the condensation absorber and then extracted with acidic waste liquid, and the heavy component after refined separation is extracted and treated; the light component comprises a small amount of water and hydrogen chloride.

2. A process for the production of 3-chloropropene and dichloropropanol as a co-product according to claim 1, characterized in that, The pure dichloropropanol product is collected at 174-185℃; the hydrochlorination product liquid comprises 1,3-dichloro-2-propanol, 2,3-dichloro-1-propanol, a catalyst, water and a small amount of unreacted glycerol, and byproducts glycerol acid ester organic matter and chloropropylene glycol acid ester organic matter; and the heavy component comprises one or more of water, glycerol monoester, chloropropylene glycol monoester, diglycerol monoester, glycerol dimer and glycerol dimer acid ester.

3. A process for the production of 3-chloropropene and dichloropropanol as a co-product according to claim 1, characterized in that, The preheating temperature of the raw material propylene is 350-510℃, and / or the preheating temperature of the raw material chlorine gas is 350-510℃.

4. A process for the production of 3-chloropropene and dichloropropanol as a co-product according to claim 3, characterized in that, The preheated propylene and chlorine gas are subjected to halogenation in a halogenation reactor; wherein the molar ratio of propylene to chlorine gas entering the halogenation reactor is (1.5-30):

1.

5. A process for the production of 3-chloropropene and dichloropropanol as a co-product according to claim 1, characterized in that, The reaction temperature of the halogenation reaction is greater than 500℃.

6. A process for the production of 3-chloropropene and dichloropropanol as a co-product according to claim 1, characterized in that, The glycerol and hydrogen chloride enter the hydrochlorination reactor to undergo hydrochlorination at a molar ratio of (0.05-0.5):

1.

7. A process for the production of 3-chloropropene and dichloropropanol as a co-product according to claim 1, characterized in that, The catalyst is an organic acid.

8. A process for the production of 3-chloropropene and dichloropropanol as a co-product according to claim 7, characterized in that, The catalyst is one or more of anhydrous acetic acid, hexanoic acid, octanoic acid and adipic acid.

9. The process for the production of 3-chloropropene and dichloropropanol as by-products according to claim 1, characterized in that, The reaction temperature of the hydrochlorination reaction is 80-130℃.

10. A process for the production of 3-chloropropene and dichloropropanol as a co-product according to claim 1, characterized in that, The liquid phase part of the halogenation product after heat exchange is refined and separated in a rectifying column to obtain 3-chloropropylene; wherein the light halogenated hydrocarbon with a boiling point lower than that of 3-chloropropylene is extracted from the top of the rectifying column, and the D-D mixed agent is extracted from the bottom of the rectifying column.

11. An apparatus for the co-production of 3-chloropropene and dichloropropanol, characterized in that, The device for co-producing 3-chloropropene and dichloropropanol can be used in the production process for co-producing 3-chloropropene and dichloropropanol according to any one of claims 1 to 10, and the device for co-producing 3-chloropropene and dichloropropanol comprises: a halogenation reactor (5); a heat exchanger (6) connected with the halogenation reactor (5), a gas phase portion (8) take-out pipeline connected with the top of the heat exchanger (6), and a crude chloropropene (7) take-out pipeline connected with the bottom of the heat exchanger (6); a rectifying tower (9) connected with the crude chloropropene (7) take-out pipeline and a take-in port of the rectifying tower (9), a light halogenated hydrocarbon (18) take-out pipeline connected with the top of the rectifying tower (9), a D-D mixed agent (19) take-out pipeline connected with the bottom of the rectifying tower (9), and a 3-chloropropene (20) take-out pipeline connected with the rectifying tower (9); a hydrochlorination reactor (12) connected with the heat exchanger (6) through the gas phase portion (8) take-out pipeline, a glycerol (10) take-in pipeline and a catalyst (11) take-in pipeline connected with the hydrochlorination reactor (12), a non-condensable gas (13) take-out pipeline connected with the top of the hydrochlorination reactor (12), and a hydrochlorination product liquid (14) take-out pipeline connected with the bottom of the hydrochlorination reactor (12); a refining unit (16) connected with the hydrochlorination reactor (12) through the hydrochlorination product liquid (14) take-out pipeline, a light component (25) take-out pipeline connected with the top of the refining unit (16), and a heavy component (23) take-out pipeline connected with the bottom of the refining unit (16); a condensation absorber (15) connected with the refining unit (16) through the light component (25) take-out pipeline, connected with the hydrochlorination reactor (12) through the non-condensable gas (13) take-out pipeline, and further connected with a circulating propylene (17) pipeline and an acidic waste liquid (24) take-out pipeline.

12. A device for co-production of 3-chloropropene and dichloropropanol according to claim 11, characterized in that, The device further comprises: a propylene preheater (3) connected with a propylene (1) take-in pipeline and connected with the condensation absorber (15) through the circulating propylene (17) pipeline; a chlorine preheater (4) connected with a chlorine (2) take-in pipeline; wherein the propylene preheater (3) and the chlorine preheater (4) are respectively connected with the halogenation reactor (5).

13. A process for the production of epichlorohydrin, characterized in that, The production process for the epichlorohydrin comprises the production process for co-producing 3-chloropropene and dichloropropanol according to any one of claims 1 to 10; and / or the production device used in the production process for the epichlorohydrin comprises the device for co-producing 3-chloropropene and dichloropropanol according to claim 11 or 12.

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