Production process and device for co-production of 3-chloropropene and dichloropropanol, and application of production process and device

Abstract

The invention provides a production process for co-production of 3-chloropropene and dichloropropanol and a device and application thereof, the production process comprises the following steps: raw materials propylene and chlorine are subjected to a halogenation reaction in a halogenation reactor, a halogenation reaction product enters a heat exchanger to be subjected to heat exchange and then is divided into a gas phase part and a liquid phase part, the hydrogen chloride gas in the gas phase part is used as a raw material and is subjected to a hydrochlorination reaction with glycerol and a catalyst in a hydrochlorination reactor for preparing dichloropropanol; according to the method, a large amount of hydrogen chloride as a byproduct in the propylene high-temperature chlorination process is fully utilized and supplied to a chlorine source required in the glycerol hydrochlorination process, so that the byproduct recovery treatment process in the propylene high-temperature chlorination process is omitted, the production process is simplified, the energy consumption is reduced, and the device is simple to operate, low in cost and high in yield. The equipment is high in production efficiency and beneficial to industrial application.

Description

Technical Field

[0001] The present application relates to the technical field of epichlorohydrin production, and specifically to a production process for co-producing 3-chloropropene and dichloropropanol, and a device and application thereof. Background Art

[0002] Epichlorohydrin (ECH), also known as epichlorohydrin or 3-chloro-1,2-epoxypropane, is a colorless liquid that is insoluble in water and has moderate toxicity. It is an important raw material for the production of epoxy resins, synthetic glycerin 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 an important intermediate in petrochemicals and has a wide range of uses.

[0003] At present, the hydrogen peroxide method is often used in production to produce epichlorohydrin, which is prepared by direct epoxidation of the raw material 3-chloropropene, which is produced by the halogenation reaction of propylene and chlorine. Although this method solves the problem of saponification wastewater and waste residue generated in the chlorohydrin reaction in the original high-temperature chlorination method and the alkali saponification step in the glycerol saponification method, and the production process route is simple, a large amount of hydrogen chloride by-product during production needs to be further processed, resulting in high production costs and complicated processing procedures. Summary of the invention

[0004] In view of this, the present application provides a co-production process and device for 3-chloropropene and dichloropropanol, which solves the technical problem in the prior art that the byproduct hydrogen chloride produced during the production of epichlorohydrin needs to be further processed, thereby leading to high production costs.

[0005] The present application provides a production process for co-producing 3-chloropropene and dichloropropane, which is characterized by comprising: causing raw materials propylene and chlorine to undergo a halogenation reaction in a halogenation reactor, wherein the product of the halogenation reaction is a mixed gas of 3-chloropropene, hydrogen chloride and other halogenated by-products; the halogenation reaction 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 the reaction product hydrogen chloride, and the hydrogen chloride gas in the gas phase part is used as a raw material to undergo a hydrochlorination reaction with glycerol and a catalyst in a hydrochlorination reactor to prepare dichloropropane; the liquid phase part is a mixed liquid of 3-chloropropene and by-products with a boiling point higher than that of 3-chloropropene, and the liquid phase part enters a distillation tower for separation and purification to obtain 3-chloropropene.

[0006] In a possible implementation, the non-condensable gas taken out from the top of the gas phase after passing through the hydrochlorination reactor is subjected to condensation and absorption treatment, and the treated propylene is used as a raw material for the halogenation reaction again.

[0007] In a possible implementation, the hydrochlorination product liquid extracted from the bottom of the hydrochlorination reactor is refined and separated, pure dichloropropanol product is collected at 174-185° C., the separated catalyst and unreacted glycerol are circulated to the hydrochlorination reactor, the light components after refinement and separation are condensed and absorbed and then extracted with the acidic waste liquid, and the heavy components after refinement and separation are extracted and processed; wherein the hydrochlorination product liquid includes 1,3-dichloro-2-propanol, 2,3-dichloro-1-propanol, catalyst, water and a small amount of unreacted glycerol, and by-product glycerate organic matter and chloropropylene glycol ester organic matter; the heavy components include one or more of water, glycerol monoester, chloropropylene glycol monoester, diglycerol monoester, glycerol dimer, and glycerol dimer ester; the light components include a small amount of water and hydrogen chloride.

[0008] In a possible implementation, the raw materials propylene and chlorine are preheated and then 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 a possible implementation, the preheated propylene and chlorine undergo a halogenation reaction in a halogenation reactor; wherein the molar ratio of propylene to chlorine entering the halogenation reactor is (1.5-30):1, and preferably, the reaction temperature of the halogenation reaction is greater than 500°C.

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

[0011] In a possible implementation, the liquid phase of the halogenated reaction product after heat exchange is distilled and separated in a distillation tower to purify 3-chloropropene; wherein light halogenated hydrocarbons with a boiling point lower than 3-chloropropene are extracted from the top of the distillation tower, and DD mixture is extracted from the bottom of the distillation tower.

[0012] According to the second aspect of the present application, the present application provides a device for co-producing 3-chloropropene and dichloropropanol, which can be used in the above-mentioned production process for co-producing 3-chloropropene and dichloropropanol, and the device comprises: a halogenation reactor; a heat exchanger, the halogenation reactor is connected to the heat exchanger, the top of the heat exchanger is connected to a gas phase part production pipeline, and the bottom of the heat exchanger is connected to a crude chloropropene production pipeline; a distillation tower, the crude chloropropene production pipeline is connected to the production port of the distillation tower, the top of the distillation tower is connected to a light halogenated hydrocarbon production pipeline, and the bottom of the distillation tower is connected to a DD mixture production pipeline, The distillation tower is connected to a 3-chloropropylene extraction pipeline; a hydrochlorination reactor, the hydrochlorination reactor is connected to the heat exchanger through the gas phase extraction pipeline, the hydrochlorination reactor is also connected to a glycerol extraction pipeline and a catalyst extraction pipeline, the top of the hydrochlorination reactor is connected to a non-condensable gas extraction pipeline, and the bottom of the hydrochlorination reactor is connected to a hydrochlorination product liquid extraction pipeline; a refining unit, the hydrochlorination reactor is connected to the refining unit through the hydrochlorination product liquid extraction pipeline, the top of the refining unit is connected to a light component extraction pipeline, and the bottom of the refining unit is connected to a heavy component extraction pipeline;

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

[0014] In a possible implementation, the device for co-producing 3-chloropropene and dichloropropanol further includes: a propylene preheater, to which a propylene intake pipeline is connected, and the propylene preheater is connected to the condensation absorber through the circulating propylene pipeline; a chlorine preheater, to which a chlorine intake pipeline is connected; wherein the propylene preheater and the chlorine preheater are respectively connected to the halogenation reactor.

[0015] According to the third aspect of the present application, the present application provides a production process of epichlorohydrin, the production process of epichlorohydrin includes the above-mentioned production process for co-producing 3-chloropropene and dichloropropanol; and / or the production device used in the production process of epichlorohydrin includes the above-mentioned device for co-producing 3-chloropropene and dichloropropanol.

[0016] The present application provides a production process and device for co-producing 3-chloropropene and dichloropropane, wherein raw materials propylene and chlorine undergo halogenation reaction in a halogenation reactor, and the product of the halogenation reaction is a mixed gas of 3-chloropropene, hydrogen chloride and other halogenated byproducts; the halogenated reaction 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 the reaction product hydrogen chloride, and the hydrogen chloride gas in the gas phase part is used as a raw material to undergo a hydrochlorination reaction with glycerol and a catalyst in a hydrochlorination reactor to prepare dichloropropane; the liquid phase part is a mixed liquid of 3-chloropropene and byproducts with a boiling point higher than that of 3-chloropropene, and the liquid phase part enters a distillation tower for separation and purification to obtain 3-chloropropene. The present application uses the hydrogen chloride produced as a byproduct in the process of producing chloropropene by high-temperature chlorination of propylene as the source of hydrogen chloride in the process of hydrochlorination of glycerol, and the hydrochloric acid gas containing propylene enters the hydrochlorination reactor together with glycerol and a catalyst for substitution reaction, and after the hydrochloric acid gas is consumed, the remaining non-condensable gas (mainly propylene) enters the propylene high-temperature chlorination reactor again after purification. The device combines two methods for producing epichlorohydrin, the co-production of the glycerol method and the hydrogen peroxide method, which solves the need to treat chlorine-containing wastes such as hydrogen chloride produced in the production process of the hydrogen peroxide method, and solves the raw materials required for the production of the glycerol method. It not only eliminates the by-product recovery and treatment process in the high-temperature chlorination process of propylene, simplifies the production process and reduces energy consumption, but also can share public works, separation devices and epichlorohydrin product tanks and other devices. The co-production device is simple to operate, has high production efficiency and is conducive to industrial application. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Shown is a schematic structural diagram of a device for co-producing allyl chloride and dichloropropanol provided in the present application.

[0018] Description of reference numerals:

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

[0020] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0021] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0022] The main raw materials for producing epichlorohydrin by the glycerol chlorination and saponification method are industrial glycerol, 30% caustic soda and gaseous hydrogen chloride, including the hydrochlorination of glycerol to produce 1,3-dichloro-2-propanol and 2,3-dichloro-1-propanol, separation of dichloropropanol, saponification of dichloropropanol and refining of epichlorohydrin. This method has the characteristics of simple production process, short process, less emission of "three wastes", low investment, low operating cost and renewable raw materials. The glycerol method has increased from 10% of the total output to about 39% at present, but its production process involves the use of raw material hydrogen chloride; the hydrogen peroxide method for producing epichlorohydrin is to prepare epichlorohydrin by direct epoxidation of 3-chloropropylene. The raw material is 3-chloropropene, which is generated by halogenation reaction of propene and chlorine. This method completely solves the problem of saponification wastewater and waste residue produced by chlorohydrin reaction and alkali saponification process in the original chloropropene method. The production process route is simple, but a large amount of hydrogen chloride by-products during production need to be further processed; if 3-chloropropene is produced alone through the existing production process, currently, for every ton of 3-chloropropene produced, 0.48 tons of hydrogen chloride gas will be produced as a by-product, and then about 2 tons of 25% hydrochloric acid solution will be produced as a by-product. The by-product hydrogen chloride gas takes away a lot of heat and becomes hydrochloric acid after absorption. It is necessary to consider the dissolution of hydrogen chloride gas, the generation and treatment of hydrochloric acid, and the storage process separately. The production of dichloropropane by the existing glycerol method requires the consumption of a large amount of hydrogen chloride, and 5 to 6 tons of steam per ton.

[0023] Therefore, the present application provides a production process and device for the co-production of 3-chloropropene and dichloropropane, wherein the hydrogen chloride produced as a by-product in the process of producing chloropropene by high-temperature chlorination of propylene is used as the source of hydrogen chloride in the process of hydrochlorination of glycerol, and the hydrogen chloride enters the hydrochlorination reactor together with glycerol and a catalyst for substitution reaction. After the hydrogen chloride is consumed, the remaining non-condensable gas (mainly propylene) is purified and used again as a raw material for halogenation reaction. The co-production device can produce chloropropene and dichloropropane at the same time, the front section is used for the production of epichlorohydrin by hydrogen peroxide method; the rear section is used for the production of epichlorohydrin by glycerol method, and the two production methods of epichlorohydrin are combined. The method and device of propane are combined to solve the problem of needing to treat chlorine-containing wastes such as hydrogen chloride generated in the production process of hydrogen peroxide method, and solve the problem of hydrogen chloride raw materials required for glycerol production. It not only saves the by-product recovery and treatment process in the high-temperature chlorination process of propylene, simplifies the production process and reduces energy consumption, but also can share public works, separation devices and epichlorohydrin product tanks and other devices, effectively utilizes hydrogen chloride generated in the high-temperature chlorination process of propylene, greatly improves the utilization efficiency of chlorine elements, reduces the generation of chlorine-containing wastes, thereby reducing the generation and treatment process of waste strong acid, and further reducing production costs.

[0024] The allyl chloride unit and the dichloropropanol unit can share public works, separation units and epichlorohydrin product tanks. Specifically, the hot steam can first be passed to devices and equipment with higher temperature requirements, such as halogenation reactors, propylene preheaters and chlorine preheaters. After one heat exchange, the remaining steam can also be used to heat the glycerol hydrochlorination reactor; the nitrogen protection pipeline and the emergency pipeline can be shared; 3-chloropropene can be used for epoxidation to prepare epichlorohydrin, and dichloropropanol can also be saponified to prepare epichlorohydrin. The crude epichlorohydrin product after preliminary separation can share the distillation and purification unit, and the purified epichlorohydrin product tank can also be shared.

[0025] Figure 1 The schematic diagram of the structure of a device for co-producing 3-chloropropene and dichloropropanol provided in the present application is shown as an exemplary illustration. Figure 1 The present invention describes the production process and device for co-producing 3-chloropropene and dichloropropanol. Figure 1 As shown, propylene 1 enters into propylene preheater 3 through propylene inlet, the temperature of propylene preheater 3 is 350-510°C, chlorine 2 enters into chlorine preheater 4 through chlorine inlet, the temperature of chlorine preheater 4 is 350-510°C, and the preheated propylene 1 and chlorine 2 enter into halogenation reactor 5 at a molar ratio of (1.5-30):1. Halogenation reaction occurs between propylene 1 and chlorine 2 at a temperature above 500°C to obtain a mixed gas of propylene, 3-chloropropene, hydrogen chloride and other halogenated by-products (including 1-chloropropane, 2-chloropropane, 1-chloropropene, 1,2-dichloropropane, 1,3-dichloropropane, 1,2-dichloropropene, 1,3-dichloropropene, etc.).

[0026] The mixed gas of propylene, 3-chloropropylene, hydrogen chloride and other halogenated by-products enters the heat exchanger 6. After the heat exchange process, the temperature drops from 500°C at the outlet of the halogenation reactor 5 to below 35°C. At this time, the mixed gas is divided into gas and liquid phases. The liquid phase part is extracted from the bottom of the heat exchanger 6. The liquid phase part is a mixed solution of 3-chloropropylene and by-products with a boiling point higher than 3-chloropropylene (including two dichloropropanes and two dichloropropylenes, and a small amount of monochloropropane, etc.). The liquid phase part extracted from the bottom of the heat exchanger 6 enters the distillation tower 9 for separation and purification to obtain a 3-chloropropylene product. The light component is a small amount of light halogenated hydrocarbons with a boiling point lower than 3-chloropropylene, which are extracted from the top of the distillation tower 9. The heavy component is a polyhalogenated hydrocarbon DD mixture (a mixture of 1,2-dichloropropane and 1,3-dichloropropylene) extracted from the bottom of the distillation tower 9. The gas phase part 8 is extracted from the top of the heat exchanger 6. The gas phase part 8 is a mixed gas of the remaining unreacted propylene and hydrogen chloride.

[0027] Glycerol and hydrogen chloride 10 are introduced into a hydrochlorination reactor 12 together with a catalyst 11 (the catalyst is a common organic acid, such as anhydrous acetic acid, hexanoic acid, octanoic acid, adipic acid, etc.) at a molar ratio of (0.05-0.5):1, and a hydrochlorination reaction occurs at 80-130°C to consume glycerol and hydrogen chloride to generate 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 and part of hydrogen chloride that do not participate in the reaction) is extracted from the top of the hydrochlorination reactor 12, and the remaining hydrogen chloride, halogenated hydrocarbons and water are removed by a condensation absorber 15 to obtain propylene 17, which is circulated back to the propylene preheater 3 and enters the halogenation reactor 5 together with fresh propylene to continue the propylene halogenation reaction, and the acidic waste liquid 24 containing a small amount of halogenated hydrocarbons is discharged from the bottom of the condensation absorber 15 to be treated in a waste liquid treatment workshop.

[0028] The hydrochlorination product liquid 14 after the reaction in the hydrochlorination reactor 12 is extracted from the bottom of the hydrochlorination reactor 12. The hydrochlorination product liquid 14 contains two main products, 1,3-dichloro-2-propanol and 2,3-dichloro-1-propanol, and an organic acid catalyst, water, a small amount of unreacted glycerol, and by-products of glyceryl esters and chloropropylene glycol esters, namely, glyceryl monoesters, chloropropylene glycol monoesters, diglyceryl monoesters, glyceryl dimers, and glyceryl dimer esters, which are sent to the refining unit 16 for refining and separation. The product pure dichloropropanol 21 is collected at 174-185° C., and the excess organic acid catalyst and unreacted glycerol are separated and refluxed to the hydrochlorination reactor 12 through the catalyst 11 intake port. The heavy components (water and glyceryl esters and chloropropylene glycol esters organic matter) taken out from the bottom of the refining unit 16 are sent to the waste liquid treatment workshop for treatment; a small amount of light components (a small amount of water and hydrogen chloride) are taken out from the top of the refining unit 16, and the light components are condensed in the condensation absorber 15 and sent to the waste liquid treatment workshop with the acidic waste liquid 24.

[0029] In the halogenation reactor 5, propylene should be kept in an excess state, and chlorine should not be excessive, thereby causing corrosion of the reactor; the unused propylene and by-product hydrogen chloride mixed gas directly enter the hydrochlorination reactor 12, as a source of hydrogen chloride, to carry out glycerol hydrochlorination to produce dichloropropanol, and continue the reaction. After the remaining small amount of hydrogen chloride, halogenated hydrocarbons and water are removed from the propylene in the mixed gas, it is dried and then enters the halogenation reactor 5 to participate in the halogenation reaction, and finally reaches the co-production process of 3-chloropropene-dichloropropanol. The co-production device fully utilizes a large amount of by-product hydrogen chloride in the high-temperature chlorination process of propylene to supply the chlorine source required in the glycerol hydrochlorination process, thereby eliminating the by-product recovery and treatment process in the high-temperature chlorination process of propylene, simplifying the production process, reducing energy consumption, simple operation, high equipment production efficiency and conducive to industrial application.

[0030] Example 1

[0031] The raw material propylene enters the propylene preheater 3 through the propylene inlet, and the propylene is vaporized at 510°C. The raw material chlorine enters the chlorine preheater 4 through the chlorine inlet, and the chlorine is vaporized at 510°C. The vaporized propylene and the vaporized chlorine 2 enter the halogenation reactor 5 at a molar ratio of 5:1 to undergo a halogenation reaction. The vaporized propylene and the chlorine propylene generate free radicals, and the chlorine becomes a chlorine free radical. The two collide with each other, and the propylene is chlorinated at a high temperature above 500°C to generate propylene, 3-chloropropylene, hydrogen chloride and other halogenated radicals. Byproducts, other halogenated byproducts include 1-chloropropane, 2-chloropropane, 1-chloropropene, 1,2-dichloropropane, 1,3-dichloropropene, 1,2-dichloropropene, 1,3-dichloropropene, etc. Propylene, 3-chloropropene, hydrogen chloride and other byproducts enter the heat exchanger 6 for heat exchange treatment. After heat exchange treatment, the temperature drops from 500°C at the outlet of the halogenation reactor to below 35°C. At this time, the mixed gas is divided into gas-liquid two phases, the liquid phase component is extracted from the bottom of the heat exchanger, and the gas phase component is extracted from the top of the heat exchanger.

[0032] The gas phase component is a mixed gas of the remaining propylene and hydrogen chloride that have not reacted in the halogenation reactor. The raw material glycerol and hydrogen chloride enter 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 raw material and hydrogen chloride undergo a hydrochlorination reaction at 107.6°C to generate a hydrochlorination product liquid 14. The hydrochlorination product liquid 14 includes two main products, 1,3-dichloro-2-propanol and 2,3-dichloro-1-propanol, an organic acid catalyst, water, a small amount of unreacted glycerol, and by-products glyceryl esters and chloropropylene glycol esters, namely glycerol. The hydrochlorination product liquid 14 enters the refining unit, is further refined at 180°C to produce pure dichloropropanol, and the excess organic acid catalyst is separated. 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 glycerol esters and chloropropylene glycol esters organic matter) extracted from the bottom of the refining unit is sent to the waste liquid treatment workshop, and the light component (a small amount of water and hydrogen chloride) is extracted from the top of the refining unit. After condensation in the condensation absorber, the light component is sent to the waste liquid treatment workshop together with the acidic waste liquid for further treatment.

[0033] The liquid components extracted from the bottom of the heat exchanger enter the distillation tower 9 for separation and purification to obtain 3-chloropropylene product, the light components extracted from the top of the distillation tower 9 are a small amount of light halogenated hydrocarbons with a boiling point lower than 3-chloropropylene, and the heavy components extracted from the bottom of the distillation tower 9 are polyhalogenated hydrocarbon DD mixture (a mixture of 1,2-dichloropropane and 1,3-dichloropropylene).

[0034] Through the production process of Example 1, the selectivity of 3-chloropropylene is 85.10%, and the selectivity of dichloropropanol is 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 gasified at 355°C, propylene and chlorine enter the halogenation reactor at a molar ratio of 1.75:1, propylene and chlorine undergo halogenation reaction at 485°C, and after heat exchange treatment, glycerol and hydrogen chloride enter the hydrochlorination reactor at a molar ratio of 0.338:1, the content of the catalyst added to the hydrochlorination reactor is 4.17% (w / w), and the hydrochlorination reaction is carried out at 93.2°C. Excess propylene is subjected to removal of hydrogen chloride, water and halogenated hydrocarbons and circulated into the halogenation reactor, and crude 3-chloropropylene and crude dichloropropanol are separated and purified to obtain 3-chloropropylene and dichloropropanol products.

[0038] Through the production process of Example 2, the selectivity of 3-chloropropylene is 64.03%, and the selectivity of dichloropropanol is 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 gasified at 433°C, and propylene and chlorine enter the halogenation reactor at a molar ratio of 3.5:1. Propylene and chlorine undergo halogenation reaction at 493°C. After heat exchange treatment, glycerol and hydrogen chloride enter the hydrochlorination reactor at a molar ratio of 0.109:1. The content of the catalyst added to the hydrochlorination reactor is 2.35% (w / w). The hydrochlorination reaction is carried out at 86.5°C. Excess propylene is subjected to removal of hydrogen chloride, water and halogenated hydrocarbons and circulated into the halogenation reactor. Crude 3-chloropropylene and crude dichloropropanol are separated and purified to obtain 3-chloropropylene and dichloropropanol products.

[0042] Through the production process of Example 3, the selectivity of 3-chloropropylene is 76.78%, and the selectivity of dichloropropanol is 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 gasified at 387°C, and propylene and chlorine enter the halogenation reactor at a molar ratio of 4.15:1. Propylene and chlorine undergo halogenation reaction at 501°C. After heat exchange treatment, glycerol and hydrogen chloride enter the hydrochlorination reactor at a molar ratio of 0.461:1. The content of the catalyst added to the hydrochlorination reactor is 8.15% (w / w). The hydrochlorination reaction is carried out at 113.3°C. Excess propylene is subjected to removal of hydrogen chloride, water and halogenated hydrocarbons, and circulated into the halogenation reaction device. Crude 3-chloropropylene and crude dichloropropanol are separated and purified to obtain 3-chloropropylene and dichloropropanol products.

[0046] Through the production process of Example 4, the selectivity of 3-chloropropylene is 88.25%, and the selectivity of dichloropropanol is 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 gasified at 455°C, and propylene and chlorine enter the halogenation reactor at a molar ratio of 28.75:1. Propylene and chlorine undergo halogenation reaction at 501°C. After heat exchange treatment, glycerol and hydrogen chloride enter the hydrochlorination reactor at a molar ratio of 0.461:1. The content of the catalyst added to the hydrochlorination reactor is 8.15% (w / w). The hydrochlorination reaction is carried out at 100.4°C. Excess propylene is subjected to removal of hydrogen chloride, water and halogenated hydrocarbons and circulated into the halogenation reaction device. Crude 3-chloropropylene and crude dichloropropanol are separated and purified to obtain 3-chloropropylene and dichloropropanol products.

[0050] Through the production process of Example 4, the selectivity of 3-chloropropylene is 88.25%, and the selectivity of dichloropropanol is 87.08%.

[0051] Table 1 Comparison of the selectivity of 3-chloropropylene and dichloropropanol in Examples 1-5

[0052]

[0053]

[0054] It can be seen from Table 1 that when the vaporization temperatures of propylene and chlorine in the preheater are both 387°C, the molar ratio of propylene to chlorine entering the halogenation reactor is 4.15:1, the hydrochlorination reaction temperature is 113.3°C, 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-chloropropylene and dichloropropanol is the highest. The selectivity is the proportion of all products of chloropropylene in the halogenation reaction process, and the proportion of all products of dichloropropanol in the hydrochlorination reaction process.

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

[0056] The temperature of the hydrochlorination reaction in Example 2 is slightly higher than that in Example 3, and the amount of catalyst added is slightly higher than that in Example 3. Therefore, the selectivity of 3-chloropropylene and dichloropropylene in Example 2 is slightly higher than that in Example 3.

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

[0058] In Example 5, the molar ratio of propylene to chlorine is 28.75:1. A larger molar ratio increases the selectivity of allyl chloride, but a large amount of unreacted propylene needs to be heated, and the amount of hydrochloric acid gas generated is small. In the subsequent hydrochlorination reaction, the amount of hydrogen chloride obtained is small, and the product is mainly monochloropropylene glycol, and the selectivity of dichloropropylene glycol is very low.

[0059] It can be seen that the molar ratio of propylene halogenation and the preheating temperature directly affect the selectivity of 3-chloropropylene; while the molar ratio of glycerol and hydrogen chloride entering the hydrochlorination reactor and the content of the catalyst added in the hydrochlorination reactor directly affect the selectivity of dichloropropanol.

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

[0061] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A production process for co-producing 3-chloropropene and dichloropropanol, characterized in that: include: The raw materials propylene and chlorine are subjected to a halogenation reaction in a halogenation reactor, wherein the product of the halogenation reaction is a mixed gas of 3-chloropropylene, hydrogen chloride and other halogenated byproducts; The halogenation reaction 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 the reaction product hydrogen chloride, and the hydrogen chloride gas in the gas phase part is used as a raw material to undergo a hydrochlorination reaction with glycerol and a catalyst in a hydrochlorination reactor to prepare dichloropropane; the liquid phase part is a mixed liquid of 3-chloropropene and by-products with a boiling point higher than 3-chloropropene, and the liquid phase part enters a distillation tower for separation and purification to obtain 3-chloropropene.

2. A production process for co-producing 3-chloropropene and dichloropropanol according to claim 1, characterized in that: The non-condensable gas taken out from the top of the gas phase after passing through the hydrochlorination reactor is subjected to condensation and absorption treatment, and the treated propylene is used as the raw material for the halogenation reaction again.

3. A production process for co-producing 3-chloropropene and dichloropropanol according to claim 1, characterized in that: The hydrochlorination product liquid extracted from the bottom of the hydrochlorination reactor is refined and separated, and the pure dichloropropanol product is collected at 174-185° C. The separated catalyst and unreacted glycerol are recycled to the hydrochlorination reactor, and the light component after refinement and separation is condensed and absorbed and then extracted with the acidic waste liquid, and the heavy component after refinement and separation is extracted and processed; The hydrochlorination product liquid includes 1,3-dichloro-2-propanol, 2,3-dichloro-1-propanol, a catalyst, water, a small amount of unreacted glycerol, and by-product glyceryl ester organic matter and chloropropylene glycol ester organic matter; the heavy component includes one or more of water, glyceryl monoester, chloropropylene glycol monoester, diglyceryl monoester, glyceryl dimer, and glyceryl dimer ester; the light component includes a small amount of water and hydrogen chloride.

4. A production process for co-producing 3-chloropropene and dichloropropanol according to claim 1, characterized in that: The raw material propylene and the raw material chlorine are preheated and then 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.

5. A production process for co-producing 3-chloropropene and dichloropropanol according to claim 4, characterized in that: The preheated propylene and chlorine undergo a halogenation reaction in the halogenation reactor; wherein the molar ratio of propylene to chlorine entering the halogenation reactor is (1.5-30):1, and preferably, the reaction temperature of the halogenation reaction is greater than 500°C.

6. A production process for co-producing 3-chloropropene and dichloropropanol according to claim 1, characterized in that: The glycerol and hydrogen chloride enter the hydrochlorination reactor at a molar ratio of (0.05-0.5):1 to undergo a hydrochlorination reaction; preferably, the catalyst is an organic acid, and more preferably, the catalyst is one or more of anhydrous acetic acid, caproic acid, caprylic acid, and adipic acid; preferably, the reaction temperature of the hydrochlorination reaction is 80-130°C.

7. A production process for co-producing 3-chloropropene and dichloropropanol according to claim 1, characterized in that: The liquid phase of the halogenation reaction product after heat exchange is distilled and separated in a distillation tower to purify 3-chloropropene; wherein, light halogenated hydrocarbons with a boiling point lower than 3-chloropropene are produced from the top of the distillation tower, and DD mixture is produced from the bottom of the distillation tower.

8. A device for co-producing 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 7, and the device for co-producing 3-chloropropene and dichloropropanol comprises: Halogenation reactor (5); A heat exchanger (6), wherein the halogenation reactor (5) is connected to the heat exchanger (6), the top of the heat exchanger (6) is connected to a gas phase (8) extraction pipeline, and the bottom of the heat exchanger (6) is connected to a crude propylene chloride (7) extraction pipeline; A distillation tower (9), wherein the crude chloropropylene (7) extraction pipeline is connected to the extraction port of the distillation tower (9), the top of the distillation tower (9) is connected to a light halogenated hydrocarbon (18) extraction pipeline, the bottom of the distillation tower (9) is connected to a DD mixture (19) extraction pipeline, and the top of the distillation tower (9) is connected to a 3-chloropropylene (20) extraction pipeline; A hydrochlorination reactor (12), wherein the hydrochlorination reactor (12) is connected to the heat exchanger (6) via the gas phase (8) extraction pipeline, the hydrochlorination reactor (12) is also connected to a glycerol (10) extraction pipeline and a catalyst (11) extraction pipeline, the top of the hydrochlorination reactor (12) is connected to a non-condensable gas (13) extraction pipeline, and the bottom of the hydrochlorination reactor (12) is connected to a hydrochlorination product liquid (14) extraction pipeline; A refining unit (16), wherein the hydrochlorination reactor (12) is connected to the refining unit (16) via a pipeline for extracting the hydrochlorination product liquid (14), the top of the refining unit (16) is connected to a pipeline for extracting a light component (25), and the bottom of the refining unit (16) is connected to a pipeline for extracting a heavy component (23); A condensation absorber (15), wherein the condensation absorber (15) is connected to the refining unit (16) via a light component (25) extraction pipeline, and the condensation absorber (15) is connected to the hydrochlorination reactor (12) via the non-condensable gas (13) extraction pipeline. The condensation absorber (15) is also connected to a circulating propylene (17) pipeline and an acid waste liquid (24) extraction pipeline.

9. The device for co-producing 3-chloropropene and dichloropropanol according to claim 8, characterized in that: The device also includes: A propylene preheater (3), the propylene preheater (3) being connected to a propylene (1) intake pipeline, the propylene preheater (3) being connected to the condensation absorber (15) via the circulating propylene (17) pipeline; A chlorine preheater (4), wherein the chlorine preheater (4) is connected to a chlorine gas (2) intake pipeline; Wherein, the propylene preheater (3) and the chlorine preheater (4) are respectively connected to the halogenation reactor (5).

10. A process for producing epichlorohydrin, characterized in that: The production process of epichlorohydrin includes a production process for co-producing 3-chloropropene and dichloropropanol as described in any one of claims 1 to 7; and / or the production device used in the production process of epichlorohydrin includes the device for co-producing 3-chloropropene and dichloropropanol as described in claim 8 or 9.

Images