Post-treatment system and post-treatment method for high-boiling-point olefin epoxidation reaction liquid and application

Abstract

The application provides a post-treatment system for high-boiling-point olefin epoxidation reaction liquid, which comprises a first rectifying tower, a second rectifying tower, a first-stage condenser, a second-stage condenser, a preheater, an esterifier and a phase separator which are sequentially connected through pipelines, and an alcohol additive pipeline; the first rectifying tower is connected to the outlet of an epoxidation reactor for high-boiling-point olefin; and the alcohol additive pipeline is used for providing alcohol additive to the esterifier. The application also provides a post-treatment method for high-boiling-point olefin epoxidation reaction liquid, which utilizes the aforementioned post-treatment system to post-treat high-boiling-point olefin epoxidation reaction liquid. The post-treatment device is simple and easy to operate; the post-treatment system and the post-treatment method can post-treat high-boiling-point olefin epoxidation reaction liquid, avoid accumulation and concentration of organic peroxide to cause polymerization and decomposition of high-boiling-point olefin to produce oxygen, reduce the concentration of organic acid to avoid corrosion of equipment, improve the precipitation problem of catalyst and save cost.

Description

Technical Field

[0001] This invention belongs to the field of high-boiling-point olefin epoxidation production technology, specifically relating to a post-treatment system, post-treatment method and application for high-boiling-point olefin epoxidation reaction liquid. Background Technology

[0002] High-boiling-point epoxides are important organic synthesis intermediates, primarily used in the production of epoxy resins, pharmaceuticals, and fragrances. They can also be used as modifiers for organic elastomers. In recent years, with the booming development of fragrances and epoxy resins, the demand for high-boiling-point epoxides has been increasing.

[0003] Current reports indicate that epoxy olefin technology primarily stems from the production of propylene oxide (PO), mainly through the chlorohydrin process, peroxide process, and co-oxidation process. With increasing environmental and safety requirements, the chlorohydrin process has been phased out due to its high consumption of chlorine and alkali, and the generation of large amounts of wastewater. The oxidants in the peroxide process are divided into peroxy organic acids and organic peroxides. Compared to the co-oxidation process, which produces large quantities of organic peroxides, the direct use of peroxy organic acids is less economically viable. Therefore, with the widespread adoption of the co-oxidation process for PO production, the effective utilization of organic peroxides to produce epoxy organic compounds has become an important research topic.

[0004] Homogeneous epoxidation is a more mature technology than heterogeneous epoxidation due to its advantages such as high activity, simple reactor, and mild operating conditions. Common active components in olefin epoxidation catalysts are mainly molybdenum, titanium, cobalt, and vanadium. Because molybdenum has strong valence variation capabilities, organic peroxides can form complex complexes with it. These complexes increase the electrophilicity of oxygen in hydrocarbon peroxides, thereby allowing olefins to abstract oxygen and form epoxides.

[0005] Homogeneous molybdenum catalysts are the mainstream catalysts for olefin epoxidation. However, the selection of a suitable system for molybdenum catalysts depends on the solubility of the organic peroxide. For example, US404678 uses a non-polar alkyl molybdate catalyst for the epoxidation of EBHP / EB and CHP / CUM; EP0264184 uses a polar ethylene glycol molybdate catalyst for the epoxidation of TBHP / TBA. Therefore, the solubility of homogeneous catalysts has always been a key consideration in epoxidation catalysts.

[0006] Most research on epoxidation focuses on catalysts and reaction processes, with limited attention paid to the separation of organic peroxides and organic acids from the epoxidation reaction solution, particularly high-boiling-point olefins. Homogeneous catalysts, due to reaction tailing and selectivity limitations, still contain a certain amount of organic peroxides at the reaction endpoint, increasing the difficulty of subsequent separation. On one hand, the local accumulation of organic peroxides during subsequent separation can catalyze olefin polymerization and cause blockage at certain temperatures; on the other hand, organic peroxides pose a risk of decomposition at high temperatures, producing oxygen and accumulating. Furthermore, the boiling points of organic acids fall between TBA and high-boiling-point olefins, and sequential separation presents the problem of organic acid accumulation and corrosion.

[0007] Therefore, there is currently no good post-treatment method for high-boiling-point olefin epoxidation reaction solutions. Summary of the Invention

[0008] The first objective of this invention is to provide a post-treatment system for high-boiling-point olefin epoxidation reaction liquid, which can post-treat the high-boiling-point olefin epoxidation reaction liquid and effectively solve the problem of high-boiling-point olefin polymerization and decomposition oxygen production caused by local concentration of organic peroxides at high temperatures.

[0009] The second objective of this invention is to provide a post-treatment method for post-treating high-boiling-point olefin epoxidation reaction liquid using the aforementioned post-treatment system. This post-treatment method can post-treat high-boiling-point olefin epoxidation reaction liquid and effectively solves the problem of high-boiling-point olefin polymerization and decomposition oxygen production caused by local concentration of organic peroxides at high temperatures.

[0010] A third objective of this invention is to provide the application of the aforementioned post-treatment system and method in the TBHP / TBA system with a polar ethylene glycol molybdate catalyst.

[0011] To achieve the first objective of this invention, the following technical solution is adopted:

[0012] A post-treatment system for high-boiling-point olefin epoxidation reaction liquid, the post-treatment system comprising a first distillation column, a second distillation column, a first-stage condenser, a second-stage condenser, an esterifier, a phase separator, and an alcohol additive addition line connected by pipelines:

[0013] The first distillation column is connected to the outlet of the epoxidation reactor for high-boiling-point olefins, and is used to receive the high-boiling-point olefin epoxidation reaction liquid and distill it. TBA by-product is output from the top of the column, and the first column bottom material containing high-boiling-point olefins, high-boiling-point olefin epoxidation products, residual TBA and organic acids is output from the bottom of the column. The high-boiling-point olefins include olefins with a boiling point ≥200℃.

[0014] The second distillation column is connected to the bottom outlet of the first distillation column and is used to distill the first bottom material from the first distillation column. The second top material containing organic peroxides and organic acids is output from the top of the column, and the second bottom material containing high-boiling-point olefins and high-boiling-point olefin epoxide products is output from the bottom of the column for further processing in subsequent units.

[0015] The primary condenser is connected to the top outlet of the second distillation column and is used to perform primary condensation on the material from the top of the second distillation column and output the primary condensate.

[0016] The secondary condenser is connected to the outlet of the primary condenser and is used to perform secondary condensation on the primary condensate from the primary condenser and output the secondary condensate.

[0017] The esterifier is connected to the outlet of the secondary condenser, and a preheater is provided on the pipeline from the secondary condenser to the esterifier for preheating the alcohol additive input through the alcohol additive addition pipeline and the secondary condensed material from the secondary condenser to carry out the esterification reaction and output the esterification reaction liquid.

[0018] The phase separator is connected to the outlet of the esterifier and is used to perform phase separation treatment on the esterification reaction liquid from the esterifier. A non-polar light phase material containing organic esters, organic peroxides and high-boiling-point olefins is output from the top of the phase separator, and a polar heavy phase material containing alcohol auxiliaries, residual high-boiling-point olefins, residual organic esters and residual organic acids is output from the bottom of the phase separator as waste liquid.

[0019] Preferably, the inlet of the esterifier is provided with a loop distributor, and the upper part of the loop distributor is provided with a distribution hole.

[0020] Preferably, the diameter and number of the distribution holes satisfy the requirement that the pressure drop through the holes is ≤2kPa; preferably, the diameter of the distribution holes is 6-12mm; preferably, the ratio of the total area of ​​the distribution holes to the cross-sectional area of ​​the esterifier inlet is 15-50%.

[0021] Preferably, the esterifier is provided with a sieve plate, and the number of layers of the sieve plate is ≥5; more preferably, the aperture of the sieve plate is 6-12mm.

[0022] Preferably, the post-processing system further includes a circulation pipeline, the two ends of which are connected to the top outlet of the phase separator and the inlet of the epoxidation reactor, respectively, for circulating the non-polar light phase material from the phase separator to the epoxidation reactor.

[0023] Preferably, the alcohol additive addition line is connected to the inlet of the secondary condenser and / or the esterifier; and / or

[0024] The alcohol additive addition line is connected to the line from the secondary condenser to the esterifier.

[0025] Preferably, a cooler is provided on the pipeline from the esterifier to the phase separator.

[0026] Preferably, the secondary condenser is a vertical condenser; the alcohol additive addition line is connected to the end cap of the secondary condenser.

[0027] Preferably, the phase separator is a coalescer, and more preferably, it is a wire mesh coalescer.

[0028] To achieve the second objective of the present invention, a post-treatment method for a high-boiling-point olefin epoxidation reaction solution is provided, wherein the post-treatment method utilizes the aforementioned post-treatment system to post-treat the high-boiling-point olefin epoxidation reaction solution.

[0029] Preferably, the post-processing method includes the following steps:

[0030] (1) The high-boiling-point olefin epoxidation reaction liquid is transported to the first distillation column for distillation treatment, and TBA by-product is output from the top of the column, and the first column bottom material containing high-boiling-point olefin, high-boiling-point olefin epoxidation product, residual TBA and organic acid is output from the bottom of the column.

[0031] (2) The first column bottom material obtained in step (1) is sent to the second distillation column for distillation treatment. The second column top material containing organic peroxides and organic acids is output from the top of the column, and the second column bottom material containing high-boiling-point olefins and high-boiling-point olefin epoxy products is output from the bottom of the column for further processing in subsequent units.

[0032] (3) The material obtained in step (2) is transported to the first-stage condenser for first-stage condensation and the first-stage condensed material is output.

[0033] (4) The primary condensate obtained in step (3) is transported to the secondary condenser for secondary condensation, and the secondary condensate is output.

[0034] (5) The secondary condensate obtained in step (4) and the alcohol additive transported through the alcohol additive addition pipeline are preheated by the preheater and then transported to the esterifier for esterification reaction, and the esterification reaction liquid is output.

[0035] (6) The esterification reaction liquid obtained in step (5) is transported to the phase separator for phase separation treatment. A non-polar light phase material containing organic esters, organic peroxides and high-boiling-point olefins is output from its top, and a polar heavy phase material containing alcohol auxiliaries, residual high-boiling-point olefins, residual organic esters and residual organic acids is output from its bottom as waste liquid.

[0036] Preferably, the post-processing method further includes step (7), in which the non-polar light phase material obtained in step (6) is returned to the epoxidation reactor via the circulation pipeline.

[0037] Preferably, in step (5), the alcohol additives transported via the alcohol additive addition pipeline are first transported to the secondary condenser, and then preheated together with the secondary condensed material by the preheater before being transported to the esterifier;

[0038] Preferably, in step (5), the temperature is preheated to 80-110°C.

[0039] Preferably, in step (9), the esterification reaction solution is cooled by the cooler 10 before being delivered to the phase separator, preferably to 40-70°C.

[0040] Preferably, the operating conditions of the second distillation column include an operating pressure of 10-30 kPaA.

[0041] Preferably, the temperature of the primary condensate is 60-120℃; more preferably, the temperature of the secondary condensate is ≤50℃.

[0042] Preferably, the operating conditions of the esterifier include: an operating temperature of 80-110℃ and a fully liquid-phase adiabatic operation; preferably, the liquid phase flow rate in the esterifier is 2-20 mm / s and the liquid phase residence time is 0.5-2 h.

[0043] Preferably, the residence time of the esterification reaction solution in the phase separator is 0.5-2 hours.

[0044] Preferably, the alcohol auxiliaries are short-chain alcohols, and more preferably include any one or a combination of glycerol, ethylene glycol and isobutanol.

[0045] Preferably, the mass ratio of the alcohol auxiliaries to the organic acids in the secondary condensate is (3-15):1.

[0046] Preferably, after the non-polar light phase material is returned to the epoxidation reactor via the circulation pipeline (8), the content of organic esters in the feed of the first distillation column (1) is 1000-5000 ppm.

[0047] Preferably, the high-boiling-point olefins include olefins with a boiling point ≥200°C; more preferably, they include any one or a combination of cyclohexene, n-hexene, cyclododecene, cyclooctadiene, and cyclododecanetriene.

[0048] To achieve the third objective of the present invention, the present invention also provides the application of the aforementioned post-treatment system for high-boiling-point olefin epoxidation reaction liquid and the aforementioned post-treatment method in a TBHP / TBA system with a polar ethylene glycol molybdate catalyst.

[0049] The beneficial effects of this invention are as follows:

[0050] The post-treatment system and method for high-boiling-point olefin epoxidation reaction liquid of the present invention can post-treat the high-boiling-point olefin epoxidation reaction liquid, thereby avoiding the problems of high-boiling-point olefin polymerization and decomposition oxygen production caused by the accumulation and concentration of organic peroxides; reducing the concentration of organic acids to avoid corrosion of equipment; improving the catalyst precipitation problem and saving costs. Attached Figure Description

[0051] Figure 1 This is a schematic diagram of the post-treatment system for high-boiling-point olefin epoxidation reaction liquid in one embodiment of the present invention;

[0052] Figure 2 This is a schematic diagram of the esterifier in one embodiment of the post-treatment system for high-boiling-point olefin epoxidation reaction liquid of the present invention.

[0053] Figure 3 yes Figure 2 A schematic diagram of the loop distributor in one embodiment of the esterifier shown;

[0054] Figure 4 yes Figure 2 A schematic diagram of the sieve plate in one embodiment of the esterifier shown;

[0055] Figure 5 This is a schematic diagram of the post-treatment system used in the high-boiling-point olefin epoxidation reaction solution in Comparative Example 1. Detailed Implementation

[0056] The technical solution and its effects of the present invention will be further described below with reference to specific embodiments / examples. The following embodiments / examples are only for illustrating the content of the present invention, and the invention is not limited to the following embodiments or examples. Simple modifications made to the present invention based on the concept of the present invention are all within the scope of protection claimed by the present invention.

[0057] like Figure 1-4 As shown, a post-treatment system for a high-boiling-point olefin epoxidation reaction liquid includes a first distillation column 1, a second distillation column 2, a primary condenser 3, a secondary condenser 4, an esterifier 5, a phase separator 6, and an alcohol additive addition line 7 connected by pipelines.

[0058] The first distillation column 1 is connected to the outlet of the epoxidation reactor 01 for high-boiling-point olefins, and is used to receive the high-boiling-point olefin epoxidation reaction liquid and distill it. TBA by-product is output from the top of the column, and the first column bottom material containing high-boiling-point olefins, high-boiling-point olefin epoxidation products, residual TBA, and organic acids is output from the bottom of the column. The high-boiling-point olefins include olefins with a boiling point ≥200℃.

[0059] The second distillation column 2 is connected to the bottom outlet of the first distillation column 1 and is used to distill the first bottom material from the first distillation column 1. The second top material containing organic peroxides and organic acids is output from the top of the column, and the second bottom material containing high-boiling-point olefins and high-boiling-point olefin epoxide products is output from the bottom of the column for further processing in subsequent units.

[0060] The primary condenser 3 is connected to the top outlet of the second distillation column 2 and is used to perform primary condensation on the material from the top of the second distillation column 2, and output the primary condensed material.

[0061] The secondary condenser 4 is connected to the outlet of the primary condenser 3 and is used to perform secondary condensation on the primary condensate from the primary condenser 3 and output the secondary condensate.

[0062] The esterifier 5 is connected to the outlet of the secondary condenser 4, and a preheater 9 is provided on the pipeline from the secondary condenser 4 to the esterifier 5. The preheater 9 is used to preheat the alcohol additive input through the alcohol additive addition pipeline 7 and the secondary condensed material from the secondary condenser 4 to carry out the esterification reaction and output the esterification reaction liquid.

[0063] The phase separator 6 is connected to the outlet of the esterifier 5 and is used to perform phase separation treatment on the esterification reaction liquid from the esterifier 5. The non-polar light phase material containing organic esters, organic peroxides and high-boiling-point olefins is output from the top of the phase separator 6, and the polar heavy phase material containing alcohol auxiliaries, residual high-boiling-point olefins, residual organic esters and residual organic acids is output from the bottom of the phase separator 6 as waste liquid.

[0064] Those skilled in the art will understand that the first distillation column 1 is equipped with a reboiler at the bottom and a condenser at the top, for condensing the material output from the top of the first distillation column 1 and then partially outputting and partially refluxing it.

[0065] Those skilled in the art will understand that the reboiler of the second distillation column 2 is equipped with a reboiler.

[0066] Those skilled in the art will understand that the primary condensate is partially refluxed.

[0067] Those skilled in the art will understand that the esterifier 5 has a material inlet at the bottom and a material outlet at the top, and temperature measuring ports are respectively provided on the upper and lower parts of its sidewall.

[0068] The post-treatment system for high-boiling-point olefin epoxidation reaction liquid of the present invention can post-treat the high-boiling-point olefin epoxidation reaction liquid. By adding alcohol additives through pipeline 7, the esterification reaction of organic acids in the high-boiling-point olefin epoxidation reaction liquid is realized, thereby reducing the concentration of organic acids in the high-boiling-point olefin epoxidation reaction liquid and avoiding their corrosion to equipment.

[0069] In one embodiment, the inlet of the esterifier 5 is provided with a ring pipe distributor 51, and the upper part of the ring pipe distributor 51 is provided with distribution holes for uniformly distributing the feed. Preferably, the diameter and number of the distribution holes satisfy the through-hole pressure drop ≤2kPa, such as 1.9kPa, 1.8kPa, 1.7kPa, 1.6kPa, 1.5kPa, 1.4kPa, 1.3kPa, 1.2kPa, 1.1kPa, 1.0kPa, and 0.5kPa. Preferably, the diameter of the distribution holes is 6-12mm, such as 7mm, 8mm, 9mm, 10mm, and 11mm. Preferably, the ratio of the total area of ​​the distribution holes to the cross-sectional area of ​​the inlet of the esterifier 5 is 15-50%, such as 20%, 25%, 30%, 35%, 40%, and 45%.

[0070] In one embodiment, the esterifier 5 is provided with a sieve plate 52, the number of layers of the sieve plate 52 is ≥5, such as 5, 6, 7, 8, 9 and 10 or more; preferably the aperture of the sieve plate 52 is 6-12mm, such as 7mm, 8mm, 9mm, 10mm and 11mm, which helps the material to achieve a plug flow in the esterifier 5 and improves the esterification efficiency.

[0071] In one embodiment, the post-treatment system further includes a circulation pipeline 8, with its two ends connected to the top outlet of the phase separator 6 and the inlet of the epoxidation reactor 01, respectively. This circulation pipeline circulates the non-polar light phase material from the phase separator 6 to the epoxidation reactor 01, allowing the organic peroxides therein to react and be consumed again, thereby preventing the accumulation and concentration of organic peroxides that could lead to the polymerization and decomposition of high-boiling-point olefins and oxygen production. Simultaneously, the organic esters also enter the epoxidation reactor 01. Since the catalyst in the epoxidation reactor 01 is a molybdate complex of a polar system, and high-boiling-point olefins are non-polar substances, and since organic esters contain both polar and non-polar groups, their entry into the epoxidation reactor 01 helps improve the solubility of the catalyst, alleviate catalyst precipitation problems, reduce catalyst usage, and lower processing costs.

[0072] In one embodiment, the alcohol additive addition line 7 is connected to the inlet of the secondary condenser 4 and / or the esterifier 5; and / or

[0073] The alcohol additive addition line 7 is connected to the line from the secondary condenser 4 to the esterifier 5.

[0074] In this invention, the alcohol additive can be added from the inlet of the secondary condenser 4 and / or the esterifier 5, or from any position on the pipeline connected from the secondary condenser 4 to the esterifier 5.

[0075] Preferably, the alcohol additive addition line 7 is connected to the inlet of the secondary condenser 4, so that the alcohol additive can be added to the secondary condenser 4 first, and then preheated together with the secondary condensate by the preheater 9 before being transported to the esterifier 5, so that the alcohol additive and the primary condensate can be effectively mixed, which helps to improve the esterification efficiency in the esterifier 5.

[0076] In one embodiment, the secondary condenser 4 is a vertical condenser; the alcohol additive addition line 7 is connected to the end cap of the secondary condenser 4 and is used to add alcohol additives to the secondary condenser 4. The addition method can be a commonly used method in the art, such as injection.

[0077] In one embodiment, a cooler 10 is provided on the pipeline from the esterifier 5 to the phase separator 6 to cool the esterification reaction liquid from the esterifier 5 to facilitate subsequent phase separation.

[0078] In one embodiment, the phase separator 6 is a coalescer, preferably a wire mesh coalescer.

[0079] The present invention also provides a post-treatment method for a high-boiling-point olefin epoxidation reaction solution, wherein the post-treatment method utilizes the aforementioned post-treatment system to post-treat the high-boiling-point olefin epoxidation reaction solution.

[0080] like Figure 1-4 As shown, in one embodiment, the post-processing method includes the following steps:

[0081] (1) The high-boiling-point olefin epoxidation reaction liquid is transported to the first distillation column 1 for distillation treatment, and TBA by-product is output from the top of the column, and the first column bottom material containing high-boiling-point olefin, high-boiling-point olefin epoxidation product, residual TBA and organic acid is output from the bottom of the column.

[0082] (2) The first column bottom material obtained in step (1) is sent to the second distillation column 2 for distillation treatment. The second column top material containing organic peroxide and organic acid is output from the top of the column, and the second column bottom material containing high-boiling-point olefin and high-boiling-point olefin epoxy product is output from the bottom of the column for further processing in subsequent units.

[0083] (3) The material obtained in step (2) is transported to the first-stage condenser 3 for first-stage condensation and the first-stage condensed material is output.

[0084] (4) The primary condensate obtained in step (3) is transported to the secondary condenser 4 for secondary condensation, and the secondary condensate is output.

[0085] (5) The secondary condensate obtained in step (4) and the alcohol additive transported through the alcohol additive addition pipeline 7 are preheated by the preheater 9 and then transported to the esterifier 5 for esterification reaction, and the esterification reaction liquid is output.

[0086] (6) The esterification reaction liquid obtained in step (5) is transported to the phase separator 6 for phase separation treatment. The non-polar light phase material containing organic esters, organic peroxides and high-boiling-point olefins is output from the top of the separator, and the polar heavy phase material containing alcohol auxiliaries, residual high-boiling-point olefins, residual organic esters and residual organic acids is output from the bottom of the separator as waste liquid.

[0087] The post-treatment method for high-boiling-point olefin epoxidation reaction liquid of the present invention can post-treat the high-boiling-point olefin epoxidation reaction liquid. Esterification of organic acids in the high-boiling-point olefin epoxidation reaction liquid is achieved through the alcohol additive addition pipeline 7, thereby reducing the concentration of organic acids in the high-boiling-point olefin epoxidation reaction liquid and preventing corrosion of equipment. Equipment made of conventional stainless steel materials such as 304, 304L, 316, and 316L can be used. Furthermore, through phase separation, organic acids can be enriched in polar heavy phase materials and discharged as waste liquid, thereby further removing organic acids.

[0088] In one embodiment, the alcohol auxiliary is a short-chain alcohol, preferably including any one or a combination of glycerol, ethylene glycol, and isobutanol. The alcohol auxiliary can separate phases with high-boiling-point olefins and can undergo esterification reactions with organic acids.

[0089] In one embodiment, the high-boiling-point olefin includes olefins with a boiling point ≥200°C; preferably, it includes any one or a combination of cyclohexene, n-hexene, cyclododecene, cyclooctadiene, and cyclododecanetriene.

[0090] In one embodiment, after the nonpolar light phase material is returned to the epoxidation reactor 01 via the circulation pipeline 8, the content of organic esters in the material is 1000-5000ppm, such as 1500ppm, 2000ppm, 2500ppm, 3000ppm, 3500ppm, 4000ppm and 4500ppm.

[0091] Those skilled in the art will understand that after the non-polar light phase material is returned to the epoxidation reactor 01 via the circulation pipeline 8, the content of organic esters in the material remains almost unchanged compared to its content in the feed of the first distillation column 1. Therefore, in one embodiment, after the non-polar light phase material is returned to the epoxidation reactor 01 via the circulation pipeline 8, the content of organic esters in the feed of the first distillation column 1 is 1000-5000 ppm, such as 1500 ppm, 2000 ppm, 2500 ppm, 3000 ppm, 3500 ppm, 4000 ppm, and 4500 ppm.

[0092] In one embodiment, the content of organic acid in the high-boiling-point olefin epoxidation reaction solution is 4000-7000 ppm, such as 4500 ppm, 5000 ppm, 5500 ppm, 6000 ppm and 6500 ppm.

[0093] The high-boiling-point olefin epoxidation reaction solution refers to the high-boiling-point olefin epoxidation reaction solution output from the epoxidation reactor 01 used for high-boiling-point olefins.

[0094] In one embodiment, the post-processing method further includes step (7), in which the non-polar light phase material obtained in step (6) is returned to the epoxidation reactor 01 via the circulation pipeline 8.

[0095] In step (7), the non-polar light phase material obtained in step (6) is returned to the epoxidation reactor 01 via the circulation pipeline 8, so that the organic peroxides in the non-polar light phase material react again and are consumed, thereby avoiding the problems of high-boiling-point olefin polymerization and decomposition oxygen production caused by the accumulation and concentration of organic peroxides. At the same time, the organic esters therein also enter the epoxidation reactor 01. Since the catalyst in the epoxidation reactor 01 is a complex of molybdate in a polar system, and high-boiling-point olefins are non-polar substances, and since organic esters contain both polar and non-polar groups, the organic esters entering the epoxidation reactor 01 help to improve the solubility of the catalyst, improve the catalyst precipitation problem, reduce the amount of catalyst used, and reduce the processing cost.

[0096] In one embodiment, in step (5), the alcohol additives transported via the alcohol additive addition pipeline 7 are first transported to the secondary condenser 4, and then preheated together with the secondary condensate by the preheater 9 before being transported to the esterifier 5. This allows the alcohol additives and the primary condensate to be effectively mixed, and both are preheated, which helps to improve the esterification efficiency in the esterifier 5.

[0097] Preferably, in step (5), the temperature is preheated to 80-110°C, such as 85°C, 90°C, 95°C, 100°C and 105°C.

[0098] In one embodiment, in step (9), the esterification reaction solution is cooled by the cooler 10 before being delivered to the phase separator 6, preferably to 40-70°C, such as 45°C, 50°C, 55°C, 60°C and 65°C.

[0099] In one embodiment, the operating conditions of the first distillation column 1 include: an operating pressure of 30-60 kPaA, such as 32 kPaA, 34 kPaA, 36 kPaA, 38 kPaA, 40 kPaA, 42 kPaA, 44 kPaA, 46 kPaA, 48 kPaA, 50 kPaA, 52 kPaA, 54 kPaA, 56 kPaA, and 58 kPaA.

[0100] In one embodiment, the operating conditions of the second distillation column 2 include an operating pressure of 10-30 kPaA, such as 11 kPaA, 12 kPaA, 13 kPaA, 14 kPaA, 15 kPaA, 16 kPaA, 17 kPaA, 18 kPaA, 19 kPaA, 20 kPaA, 21 kPaA, 22 kPaA, 23 kPaA, 24 kPaA, 25 kPaA, 26 kPaA, 27 kPaA, 28 kPaA, and 29 kPaA.

[0101] Those skilled in the art will understand that kPaA represents the pressure under vacuum conditions.

[0102] In one embodiment, the content of isobutyric acid in the second column bottom material is ≤1ppm, such as 0.9ppm, 0.8ppm, 0.7ppm, 0.6ppm, 0.5ppm, 0.4ppm, 0.3ppm, 0.2ppm and 0.1ppm.

[0103] The organic acid in this invention refers to a small molecule organic acid, including any one or a combination of formic acid, acetic acid and isobutyric acid.

[0104] When the content of isobutyric acid in the bottom material of the second column is controlled to be ≤1ppm, it can be considered that all organic acids (including formic acid, acetic acid and isobutyric acid) have been distilled and separated into the top material of the second column.

[0105] In one embodiment, the temperature of the primary condensate is 60-120°C, such as 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, and 115°C; preferably, the temperature of the secondary condensate is ≤50°C, such as 45°C, 40°C, 35°C, 30°C, 25°C, and 20°C.

[0106] In one embodiment, the operating conditions of the esterifier 5 include: an operating temperature of 80-110°C, such as 85°C, 90°C, 95°C, 100°C, and 105°C, with all-liquid-phase adiabatic operation; preferably, the liquid phase flow rate in the esterifier 5 is 2-20 mm / s, such as 3 mm / s, 4 mm / s, 5 mm / s, 6 mm / s, 7 mm / s, 8 mm / s, 9 mm / s, 10 mm / s, 11 mm / s, 12 mm / s, 13 mm / s, 14 mm / s, 15 mm / s, 16 mm / s, 17 mm / s, 18 mm / s, and 19 mm / s; and the liquid phase residence time is 0.5-2 h, such as 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, and 110 min.

[0107] In one embodiment, the residence time of the esterification reaction solution in the phase separator 6 is 0.5-2 hours, such as 40 minutes, 50 minutes, 60 minutes, 70 minutes, 80 minutes, 90 minutes, 100 minutes, and 110 minutes.

[0108] In one embodiment, the mass ratio of the alcohol auxiliaries to the organic acids in the secondary condensate is (3-15):1, such as 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1 and 14:1.

[0109] In one embodiment, the organic acids in the secondary condensate are esterified at a rate of 60-90% in the esterifier 5, such as 65%, 70%, 75%, 80%, and 85%, with the remaining organic acids enriched in the polar heavy phase material.

[0110] In one embodiment, the concentration of organic acid in the polar heavy phase material is ≤2%, such as 1.9%, 1.8%, 1.7%, 1.6%, 1.5%, 1.4%, 1.3%, 1.2%, 1.1%, 1.0%, and 0.5%, thereby allowing the use of conventional stainless steel materials such as 304, 304L, 316, and 316L without causing corrosion to the equipment.

[0111] The post-processing method of this invention effectively solves the problem of high-boiling-point olefin polymerization and decomposition oxygen production caused by local concentration of organic peroxides at high temperatures through a recycling process; and effectively separates and concentrates organic peroxides through distillation design and two-stage condensation, and recycles organic peroxides back to the epoxidation reaction through low-temperature phase separation, thereby improving the inherent safety of the separation.

[0112] The added alcohol additives esterify and separate organic acids. The resulting organic esters are recycled to the epoxidation reactor along with the organic peroxides, which improves the catalyst precipitation problem. This not only solves the corrosion of small molecule organic acids, but also reduces the amount of catalyst used. Compared with sequential separation, it greatly reduces material loss and lowers the cost of metal materials and catalyst post-treatment.

[0113] The present invention also provides the aforementioned post-treatment system for high-boiling-point olefin epoxidation reaction liquid and the application of the aforementioned post-treatment method in the TBHP / TBA system with a polar ethylene glycol molybdate catalyst.

[0114] TBHP stands for tert-butyl hydroperoxide; TBA stands for tert-butanol.

[0115] The post-treatment system and method described above for high-boiling-point olefin epoxidation reaction solutions are also applicable to EBHP / EB or CHP / CUM systems with non-polar alkyl molybdate catalysts. However, when the above-described post-treatment method is applied to EBHP / EB or CHP / CUM systems with non-polar alkyl molybdate catalysts, the specific operating conditions will differ from those when applied to TBHP / TBA systems with polar ethylene glycol molybdate catalysts.

[0116] EBHP stands for ethylbenzene hydrogen peroxide; EB stands for ethylbenzene; CHP stands for cumene hydrogen peroxide; CUM stands for cumene.

[0117] The technical effects of the present invention are specifically illustrated below through examples and comparative examples. In the following examples and comparative examples, the TBHP / TBA system with a polar ethylene glycol molybdate catalyst is used.

[0118] The raw materials used in the following embodiments and comparative examples of this invention are as follows:

[0119] Cyclododecanetriene: purity greater than 99.9 wt%, water content less than 0.1 wt%;

[0120] TBHP / TBA solution: The main components are TBHP (tert-butyl hydroperoxide) at 55 wt%, TBA (tert-butanol) at 43.7 wt%, di-tert-butyl peroxide at 2000 ppm, water at 1100 ppm, organic acids (including formic acid, acetic acid, and isobutyric acid) at 3100 ppm, methanol at 880 ppm, acetone at 2400 ppm, and isobutanol at 3500 ppm.

[0121] Alcohol additives: Ethylene glycol, abbreviated as EG, with a purity greater than 99.5 wt% and a water content less than 500 ppm;

[0122] Molybdenum catalyst: molybdate catalyst, specifically ammonium dimolybdate ethylene glycol complex solution, with an effective active component molybdenum content of 9-12%.

[0123] The methods for determining / calculating the relevant parameters are as follows:

[0124] The TBHP content was determined by iodometric titration.

[0125] The composition of the product was determined by an Agilent 6820 gas chromatograph using an HP-PONA column.

[0126] The content of organic acids (formic acid, acetic acid, isobutyric acid) is determined by titration of total acid value;

[0127] Molybdenum content was determined by ICP in the high-boiling-point olefin epoxidation reaction solution.

[0128] The theoretical molybdenum content is calculated based on the raw material composition.

[0129] Example 1 (S1)

[0130] The aforementioned post-treatment system and method were applied to the TBHP / TBA system with a polar ethylene glycol molybdate catalyst, such as... Figure 1-4 As shown, the post-processing system is made of 304 stainless steel.

[0131] In epoxidation reactor 01, cyclododecanetriene and TBHP were reacted at 90°C for 1 hour with a molar ratio of 3:1 and a molybdenum catalyst content of 50 ppm (theoretical molybdenum content) in the total reaction feed solution, to obtain a high-boiling-point olefin epoxidation reaction solution. Its main components and contents are as follows: TBA, 22.15 wt%; cyclododecanetriene, 51.4 wt%; epoxy cyclododecanediene, 25.4 wt%; TBHP, 980 ppm; total organic acid content, 7100 ppm; heavy components, 5150 ppm.

[0132] (1) The 200 kg / h high-boiling-point olefin epoxidation reaction liquid is fed to the first distillation column 1 for distillation treatment, and 41 kg / h of TBA by-product is output from the top of the column, and the first column bottom material containing high-boiling-point olefin, high-boiling-point olefin epoxidation product, residual TBA and organic acid is output from the bottom of the column; wherein, the operating condition of the first distillation column 1 is 50 kPaA;

[0133] (2) The first column bottom material obtained in step (1) is sent to the second distillation column 2 for distillation treatment. The second column top material containing organic peroxides and organic acids is output from the top of the column, and the second column bottom material containing high-boiling-point olefins and high-boiling-point olefin epoxide products is output from the bottom of the column for further processing in subsequent units; wherein, the content of isobutyric acid in the second column bottom material is ≤1ppm; the operating pressure of the second distillation column 2 is 20kPaA;

[0134] (3) The material obtained in step (2) is transported to the first-stage condenser 3 for first-stage condensation to 100°C, and the first-stage condensed material is output.

[0135] (4) 7 kg / h of ethylene glycol (alcohol additive) is injected into the inlet of the secondary condenser 4, while the primary condensate obtained in step (3) is simultaneously transported to the secondary condenser 4 for secondary condensation, outputting secondary condensate containing ethylene glycol; wherein, the secondary condenser 4 is a total condensation operation; the mass ratio of ethylene glycol to organic acid in the secondary condensate is 4.9:1.

[0136] (5) The secondary condensate obtained in step (4) and the ethylene glycol output thereafter are preheated to 80°C by the preheater 9 and then transported to the esterifier 5 for esterification reaction, and the esterification reaction liquid is output; wherein, the esterifier 5 has a diameter of 20cm and a height of 80cm; the inlet is provided with a ring pipe distributor 51, and the upper part is provided with a distribution hole with a diameter of 8mm; the inside is provided with 6 layers of sieve plates 52, and the sieve plate 52 has a diameter of 8mm; wherein, the operating conditions of the esterifier 5 include: operating temperature of 80°C, all-liquid phase adiabatic operation; liquid phase flow rate of 3mm / s, and liquid phase residence time of 1.2h;

[0137] (6) The esterification reaction liquid obtained in step (5) is cooled to 40°C by the cooler 10 and then transported to the phase separator 6 for phase separation treatment. It stays in the phase separator 6 for 1 hour. The non-polar light phase material containing organic esters, organic peroxides and high-boiling-point olefins is output from the top, and the polar heavy phase material containing alcohol auxiliaries, residual high-boiling-point olefins, residual organic esters and residual organic acids is output from the bottom as waste liquid. The phase separator 6 is a coalescer and adopts double-wire mesh coalescing. The flow rate of the non-polar light phase material is 10.1 kg / h, and the flow rate of the polar heavy phase material is 8.6 kg / h.

[0138] (7) The non-polar light phase material obtained in step (6) is returned to the epoxidation reactor via the circulation pipeline 8.

[0139] After running for 240 hours as described above, samples were taken and analyzed from the first column bottom material, the polar heavy phase material as waste liquid, and the non-polar light phase material as circulating stream. The composition is shown in Table 1.

[0140] Example 2 (S2)

[0141] Compared with Example 1, the only differences are as follows:

[0142] The alcohol additive used is glycerol.

[0143] Example 3 (S3)

[0144] Compared with Example 1, the only differences are as follows:

[0145] The alcohol additive used is isobutanol.

[0146] Comparative Example 1 (D1)

[0147] Compared with Example 1, the only differences are as follows:

[0148] The post-processing system is as follows: Figure 5 The post-processing system shown;

[0149] It only includes steps (1)-(4), and in step (4), ethylene glycol is not injected into the secondary condenser 4, but the primary condensed material obtained in step (3) is transported to the secondary condenser 4 for secondary condensation and the secondary condensed material is output.

[0150] The secondary condensate does not separate into phases and is directly discharged as waste liquid; the waste liquid flow rate is 11.6 kg / h.

[0151] After running for 240 hours as described above, samples were taken from the first tower bottom material and the secondary condensate, which was used as waste liquid, for analysis. The composition is shown in Table 1.

[0152] Table 1. Sampling and analysis results of relevant materials after 240 hours of operation in Examples 1-3 and Comparative Example 1.

[0153]

[0154]

[0155] Based on the data in Table 1 and the comparison between Example 1 and Comparative Example 1, it can be seen that after 240 hours of operation, the molybdenum content in the first column bottom material of Example 1 was relatively high, the waste liquid flow rate was relatively low, and the contents of organic acids, cyclododecanetrienes, and TBHP in the waste liquid were relatively low. It also contained EG and esters, but Fe was not detected. Therefore, it can be concluded that...

[0156] The addition of alcohol-based additives (ethylene glycol, EG) can esterify and separate organic acids. On the one hand, organic acids are converted into organic esters, reducing the content of organic acids. On the other hand, the added alcohol-based additives promote phase separation, allowing organic acids to accumulate in the polar heavy phase material and be discharged as waste liquid. Therefore, the addition of alcohol-based additives greatly reduces the content of organic acids in the system, reduces corrosion of the equipment, lowers the grade of metal materials used in the equipment, and reduces post-treatment costs. The flow rate of the discharged waste liquid is reduced, and the loss of expensive raw material cyclododecanetriene (high-boiling-point olefin) is greatly reduced. At the same time, the content of organic peroxides in the waste liquid is reduced, improving the safety of waste liquid treatment.

[0157] The organic esters contained in the recycled high-boiling-point olefin epoxidation reaction solution promote the solubility of the molybdenum catalyst in epoxidation reactor 01, increase the content of molybdenum catalyst in the material, thereby reducing the amount of epoxidation reaction catalyst used, greatly saving the amount of metal catalyst used, and reducing post-processing costs.

Claims

1. A post-treatment system for high-boiling-point olefin epoxidation reaction solution, characterized in that, The post-processing system includes a first distillation column (1), a second distillation column (2), a primary condenser (3), a secondary condenser (4), an esterifier (5), a phase separator (6), and an alcohol additive addition line (7) connected by pipelines. The first distillation column (1) is connected to the outlet of the epoxidation reactor for high-boiling-point olefins, for receiving the high-boiling-point olefin epoxidation reaction liquid and distilling it, outputting TBA by-product from the top of the column, and outputting the first column bottom material containing high-boiling-point olefins, high-boiling-point olefin epoxidation products, residual TBA, and organic acids from the bottom of the column; the high-boiling-point olefins include olefins with a boiling point ≥200 °C. The second distillation column (2) is connected to the bottom outlet of the first distillation column (1) for distilling the first bottom material from the first distillation column (1), outputting a second top material containing organic peroxides and organic acids from the top of the column, and outputting a second bottom material containing high-boiling-point olefins and high-boiling-point olefin epoxide products from the bottom of the column for further processing in subsequent units. The primary condenser (3) is connected to the top outlet of the second distillation column (2) and is used to perform primary condensation on the material from the top of the second distillation column (2) and output the primary condensed material. The secondary condenser (4) is connected to the outlet of the primary condenser (3) and is used to perform secondary condensation on the primary condensate from the primary condenser (3) and output the secondary condensate. The esterifier (5) is connected to the outlet of the secondary condenser (4), and a preheater (9) is provided on the pipeline from the secondary condenser (4) to the esterifier (5) for preheating the alcohol additive input through the alcohol additive addition pipeline (7) and the secondary condensed material from the secondary condenser (4) to undergo an esterification reaction, and outputting the esterification reaction liquid from the esterifier (5); The phase separator (6) is connected to the outlet of the esterifier (5) and is used to perform phase separation treatment on the esterification reaction liquid from the esterifier (5). The non-polar light phase material containing organic esters, organic peroxides and high-boiling-point olefins is output from the top of the phase separator (6), and the polar heavy phase material containing alcohol auxiliaries, residual high-boiling-point olefins, residual organic esters and residual organic acids is output from the bottom of the phase separator (6) as waste liquid.

2. The post-processing system according to claim 1, characterized in that, The inlet of the esterifier (5) is provided with a ring pipe distributor (51), and the upper part of the ring pipe distributor (51) is provided with a distribution hole.

3. The post-processing system according to claim 2, characterized in that, The diameter and number of the distribution holes satisfy the requirement that the pressure drop through the holes is ≤2 kPa.

4. The post-processing system according to claim 2, characterized in that, The esterifier (5) is provided with a sieve plate (52), and the number of layers of the sieve plate (52) is ≥5.

5. The post-processing system according to claim 4, characterized in that, The aperture of the sieve plate (52) is 6-12 mm.

6. The post-processing system according to any one of claims 1-5, characterized in that, The post-processing system also includes a circulation pipeline (8), the two ends of which are connected to the top outlet of the phase separator (6) and the inlet of the epoxidation reactor, respectively, for circulating the non-polar light phase material from the phase separator (6) to the epoxidation reactor.

7. The post-processing system according to claim 6, characterized in that, The alcohol additive addition line (7) is connected to the inlet of the secondary condenser (4) and / or the esterifier (5); and / or The alcohol additive addition line (7) is connected to the line from the secondary condenser (4) to the esterifier (5).

8. The post-processing system according to claim 6, characterized in that, A cooler (10) is provided on the pipeline from the esterifier (5) to the phase separator (6).

9. A post-treatment method for a high-boiling-point olefin epoxidation reaction solution, characterized in that, The post-treatment method involves using the post-treatment system described in any one of claims 1-8 to post-treat the high-boiling-point olefin epoxidation reaction solution.

10. The post-processing method according to claim 9, characterized in that, The post-processing method includes the following steps: (1) The high-boiling-point olefin epoxidation reaction liquid is transported to the first distillation column (1) for distillation treatment, and TBA by-product is output from the top of the column, and the first column bottom material containing high-boiling-point olefin, high-boiling-point olefin epoxidation product, residual TBA and organic acid is output from the bottom of the column. (2) The first column bottom material obtained in step (1) is sent to the second distillation column (2) for distillation treatment. The second column top material containing organic peroxides and organic acids is output from the top of the column, and the second column bottom material containing high-boiling-point olefins and high-boiling-point olefin epoxy products is output from the bottom of the column for further processing in subsequent units. (3) The material obtained in step (2) is transported to the first-stage condenser (3) for first-stage condensation and the first-stage condensed material is output. (4) The primary condensate obtained in step (3) is transported to the secondary condenser (4) for secondary condensation, and the secondary condensate is output. (5) The secondary condensate obtained in step (4) and the alcohol additive transported through the alcohol additive addition pipeline (7) are preheated by the preheater (9) and then transported to the esterifier (5) for esterification reaction, and the esterification reaction liquid is output. (6) The esterification reaction liquid obtained in step (5) is transported to the phase separator (6) for phase separation treatment. The non-polar light phase material containing organic esters, organic peroxides and high-boiling-point olefins is output from the top of the separator, and the polar heavy phase material containing alcohol auxiliaries, residual high-boiling-point olefins, residual organic esters and residual organic acids is output from the bottom of the separator as waste liquid.

11. The post-processing method according to claim 10, characterized in that, The post-processing method further includes step (7), in which the non-polar light phase material obtained in step (6) is returned to the epoxidation reactor via the circulation pipeline (8).

12. The post-processing method according to claim 10, characterized in that, In step (5), the alcohol additives transported through the alcohol additive addition pipeline (7) are first transported to the secondary condenser (4), and then preheated together with the secondary condensed material by the preheater (9) before being transported to the esterifier (5).

13. The post-processing method according to claim 12, characterized in that, In step (5), preheat to 80-110 ℃.

14. The post-processing method according to claim 12, characterized in that, In step (6), the esterification reaction solution is cooled by the cooler (10) before being delivered to the phase separator (6).

15. The post-processing method according to claim 14, characterized in that, In step (6), the esterification reaction solution is cooled to 40-70 °C by the cooler (10) before being transported to the phase separator (6).

16. The post-processing method according to any one of claims 11-15, characterized in that, The operating conditions of the second distillation column (2) include: an operating pressure of 10-30 kPaA.

17. The post-processing method according to claim 16, characterized in that, The temperature of the primary condensate is 60-120 ℃.

18. The post-processing method according to claim 17, characterized in that, The temperature of the secondary condensate is ≤50℃.

19. The post-processing method according to claim 16, characterized in that, The operating conditions of the esterifier (5) include: operating temperature of 80-110 ℃ and all-liquid phase adiabatic operation.

20. The post-processing method according to claim 19, characterized in that, In the esterifier (5), the liquid phase flow rate is 2-20 mm / s and the liquid phase residence time is 0.5-2 h.

21. The post-processing method according to claim 20, characterized in that, The residence time of the esterification reaction solution in the phase separator (6) is 0.5-2 h.

22. The post-processing method according to any one of claims 11-15 and 17-21, characterized in that, The alcohol auxiliaries are short-chain alcohols.

23. The post-processing method according to claim 22, characterized in that, The alcohol auxiliaries include any one or a combination of glycerol, ethylene glycol, and isobutanol.

24. The post-processing method according to claim 22, characterized in that, The ratio of the amount of alcohol additive to the mass of organic acid in the secondary condensate is (3-15):

1.

25. The post-processing method according to any one of claims 11-15, 17-21, and 23-24, characterized in that, After the non-polar light phase material is returned to the epoxidation reactor via the circulation pipeline (8), the content of organic esters in the feed of the first distillation column (1) is 1000-5000 ppm.

26. The post-processing method according to claim 25, characterized in that, The high-boiling-point olefins include olefins with a boiling point ≥200℃.

27. The post-processing method according to claim 26, characterized in that, The high-boiling-point olefins include any one or a combination of cyclohexene, n-hexene, cyclododecene, cyclooctadiene, and cyclododecanetriene.

28. The application of a post-treatment system for a high-boiling-point olefin epoxidation reaction solution as described in any one of claims 1-8 and the post-treatment method as described in any one of claims 9-27 in a TBHP / TBA system with a polar ethylene glycol molybdate catalyst.

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