Process for purifying 1-hexene

Abstract

A process for purifying 1-hexene is disclosed. The process can include contacting a first stream containing 1-hexene and 2-ethyl-1-butene with an isomerization catalyst containing alumina, silica-alumina, a zeolite, or an ion exchange resin, or any combination thereof, under conditions sufficient to selectively isomerize at least a portion of the 2-ethyl-1-butene to 3-methyl-2-pentene and form a second stream containing 1-hexene and 3-methyl-2-pentene; and separating the second stream into a third stream containing 1-hexene and a fourth stream containing 3-methyl-2-pentene.

Description

Background of the Invention

[0002] This application claims priority to European patent application 20217807.5, filed on December 30, 2020, which is incorporated herein by reference in its entirety.

[0003] A. Field of Invention

[0004] This invention generally relates to systems and methods for purifying 1-hexene.

[0005] B. Relevant Technical Specifications

[0006] 1-Hexene is an α-olefin compound with growing demand. For example, 1-Hexene can be used to prepare a variety of high-value chemicals, such as high-density polyethylene (HDPE) and linear low-density polyethylene (LLDPE). HDPE and LLDPE have a wide range of industrial applications.

[0007] 1-Hexene is typically produced via the α-olefin process through the trimerization of ethylene. However, 1-Hexene can only be prepared to a certain purity level, such as below 99.5% by weight, using conventional α-olefin processes. For example, US20120310025A1 discloses a method for preparing 1-hexene via the trimerization of ethylene. The disclosed method yielded 1-hexene with a purity up to 97.2% by weight.

[0008] Other attempts to produce 1-hexene have been made (see, for example, US8084659B2, CN104549351B, US4236037A, RU2206557C1, US7355087B2, US4104321A, US5057638A). Typically, these processes may encounter problems of increased costs and / or low operational efficiency related to catalyst composition, processing conditions, and / or low purification results of 1-hexene. Summary of the Invention

[0009] Solutions have been found to address at least one or more problems related to obtaining high-purity 1-hexene. The trimerization of ethylene during α-olefin production can produce 1-hexene and 2-ethyl-1-butene as a byproduct. The boiling point of 2-ethyl-1-butene is similar to that of 1-hexene, making it difficult to separate from 1-hexene using conventional distillation processes. Therefore, conventional separation methods for purifying ethylene trimerization products can only produce 1-hexene with a purity up to a certain percentage. In one aspect of the invention, a catalyst comprising activated alumina, silica, silica-alumina, zeolite, and / or ion exchange resin has been discovered, which can be used for the selective isomerization of 2-ethyl-1-butene in the presence of 1-hexene. 2-Ethyl-1-butene can be isomerized to cis-3-methyl-2-pentene and trans-3-methyl-2-pentene. The boiling points of cis-3-methyl-2-pentene and trans-3-methyl-2-pentene differ sufficiently from those of 1-hexene to facilitate the separation of 1-hexene from its isomers and to produce a more purified 1-hexene stream. In some aspects, the purity of the 1-hexene stream is equal to or greater than 99.5% by weight of 1-hexene. The catalyst and method of the present invention can be used with limited or no reduction in the overall yield of 1-hexene.

[0010] In one aspect of the invention, a method for purifying 1-hexene is described. The method may include: i) contacting a first stream containing 1-hexene and 2-ethyl-1-butene with an isomerization catalyst under conditions sufficient to selectively isomerize at least a portion of 2-ethyl-1-butene to 3-methyl-2-pentene and form a second stream containing 1-hexene and 3-methyl-2-pentene; and ii) separating the second stream into a third stream containing 1-hexene and a fourth stream containing 3-methyl-2-pentene. Unless otherwise mentioned, 3-methyl-2-pentene refers to cis-3-methyl-2-pentene and trans-3-methyl-2-pentene. The boiling points of 1-hexene and 2-ethyl-1-butene are 63.4 °C and 64.5 °C, respectively, while the boiling points of cis-3-methyl-2-pentene and trans-3-methyl-2-pentene may be 67.6 °C and 70.4 °C, respectively. These differences in boiling points between 3-methyl-2-pentene and 1-hexene can aid in the separation of the 3-methyl-2-pentene and 1-hexene products. In some respects, the first stream can be used at temperatures from 40°C to 100°C, pressures from 1 bar to 10 bar, or for 0.5 hours. -1 Up to 10 hours -1 The second stream is contacted with the isomerization catalyst under conditions of liquid hourly space velocity (LISH), or any combination thereof. The second stream can be separated into a third and fourth stream by distillation. In some aspects, the second stream can be distilled at temperatures from 55°C to 75°C and / or pressures from 0 bar to 3 bar.

[0011] In some aspects, the first stream can be obtained by a linear α-olefin process. The linear α-olefin process can be a full-range linear α-olefin process and / or a process targeting 1-hexene. The linear α-olefin process can include the trimerization of ethylene to produce 1-hexene. In some aspects, the reaction product of ethylene trimerization can be purified by one or more steps to obtain the first stream. The first stream may contain 1-hexene, 2-ethyl-1-butene, optionally hexane, and optionally one or more other isomers of 1-hexene. In some aspects, the first stream comprises 90% to 99.5% by weight of 1-hexene, 0.3% to 1.5% by weight of 2-ethyl-1-butene, optionally 0.05% to 1% by weight of hexane, and optionally 0.1% to 15% by weight of one or more other isomers of 1-hexene. In some aspects, the second stream comprises 90% to 99.5% by weight of 1-hexene, 0.05% to 0.5% by weight of 2-ethyl-1-butene, 0.3% to 1.5% by weight of 3-methyl-2-pentene, optionally 0.05% to 1% by weight of hexane, and optionally 0.1% to 1.5% by weight of one or more other isomers of 1-hexene. The 3-methyl-2-pentene in the second stream can be obtained by isomerization of 2-ethyl-1-butene.

[0012] The third stream may contain at least 99.5% by weight of 1-hexene, such as 99.5% to 99.9% by weight, or 99.5% to 99.8% by weight of 1-hexene. Non-1-hexene impurities in the third stream may be less than 0.5% by weight, for example, 0 to 0.3% by weight of 2-ethyl-1-butene, 0 to 0.3% by weight of 3-methyl-2-pentene, 0 to 0.3% by weight of one or more other isomers, and 0 to 0.1% by weight of hexane. In some aspects, the optional one or more other isomers of 1-hexene may include cis-2-hexene, trans-2-hexene, cis-3-hexene, and / or trans-3-hexene.

[0013] Isomerization catalysts may include alumina, silica, silica-alumina, zeolite, and / or ion exchange resins. In some aspects, the isomerization catalyst may be loaded in a layered bed in an isomerization reactor (e.g., a reactor for carrying out an isomerization reaction), having various weight ratios of alumina, silica, silica-alumina, zeolite, and / or ion exchange resin. In some aspects, the isomerization catalyst may include alumina. The alumina used may have various properties, and non-limiting shapes include beads, extrusions, etc. In some aspects, the alumina may be shaped alumina (e.g., beads and / or extrusions) with an average particle size of 1 mm to 8 mm. In some aspects, the alumina may be activated alumina. In some aspects, the alumina (e.g., activated alumina) may contain a modifier. In some aspects, the surface area of ​​the alumina (e.g., activated alumina) may be 200 m². 2 / g to 550m 2 / g. In some aspects, alumina may include amorphous alumina. In some aspects, alumina may include amorphous γ-alumina. In some aspects, alumina may include γ-alumina and / or a mixed-phase alumina containing a modifier. The alumina modifier used can alter the physical and chemical properties of alumina, resulting in changes in its properties as an adsorbent and catalyst. In some aspects, the modifier may comprise an acidic material, such as a zeolite material. Alumina may have at least one of the alumina properties described herein, or any combination or all of them.

[0014] In some aspects, the isomerization catalyst may include zeolite. In some aspects, the zeolite may have a structure having 10- or 12-membered ring pores. In some aspects, the zeolite may be magnesium-alkali zeolite, ZSM-23, ZSM-11, ZSM-5, γ-zeolite, β-zeolite, or any combination thereof. In some aspects, the SiO2 / Al2O3 molar ratio of the zeolite may be 2 to 1000, preferably 5 to 1000, more preferably 20 to 1000, even more preferably 150 to 1000, and also preferably 45 to 280, including all ranges therebetween and all endpoints, for example, a range of 2 to 5, 5 to 20, or 45 to 1000. In some aspects, the zeolite may be in the H-form, for example, an acidic form of zeolite. In some aspects, the zeolite may be formed into a molded body, such as an extrusion. In some aspects, the zeolite may contain a binder. In some aspects, the zeolite (such as shaped zeolite) may contain 10% to 90% by weight of a binder. The binder may be alumina, silica-alumina, clay, or any combination thereof. In some aspects, the binder may be alumina. The zeolite may have at least one of the zeolite properties described herein, or any combination or all thereof. In some aspects, the isomerization catalyst may include a zeolite catalyst and an alumina catalyst. The zeolite catalyst may include the zeolite described herein. The alumina catalyst may include the alumina described herein. In some aspects, the isomerization catalyst may include a mixture comprising a zeolite catalyst and an alumina catalyst in a weight ratio of 10:1 to 1:10. In some aspects, the isomerization catalyst may include an ion exchange resin. The ion exchange resin may contain acidic sulfonic acid groups. In some aspects, the ion exchange resin may be a polystyrene-based ion exchange resin containing acidic sulfonic acid groups. In some aspects, the ion exchange resin may be an acidic cation exchange resin having a macroporous polystyrene matrix and sulfonic acid functional groups. In some specific aspects, the ion exchange resin can be an acidic cation exchange resin having macroporous styrene-divinylphenyl and sulfonic acid functional groups. In some aspects, the ion exchange resin can be in the form of hydrogen. Some aspects relate to the isomerization catalyst described above.

[0015] Other embodiments of the invention are also discussed in this application. Any embodiment discussed with respect to one aspect of the invention is also applicable to other aspects of the invention, and vice versa. All embodiments described herein are to be understood as applicable to embodiments of the invention in other aspects. It is contemplated that any embodiment discussed herein may be practiced with reference to any method or composition of the invention, and vice versa. Furthermore, the compositions and systems of the invention can be used to implement the methods of the invention.

[0016] The following includes definitions of various terms and phrases used in this specification.

[0017] As will be understood by those skilled in the art, the terms “about” or “approximately” are defined as close to. In one non-limiting embodiment, the term is defined as within ±10%, preferably within ±5%, more preferably within ±1%, and most preferably within ±0.5%.

[0018] The terms “weight%”, “volume%”, or “molar%” refer to the percentage by weight, volume, or mole of the component based on the total weight, total volume, or total number of moles of the material containing that component, respectively. In a non-limiting example, 10 grams of component in 100 grams of material is 10% by weight of the component.

[0019] The boiling points disclosed in this article are the boiling points of the corresponding compounds at standard atmospheric pressure (e.g., 760 mm Hg).

[0020] The term "basic (upper)" and its variations are defined as including the range within ±10%, ±5%, ±1%, or ±0.5%.

[0021] The terms “suppress” or “reduce” or “prevent” or “avoid” or any variations thereof, when used in the claims and / or specification, include any measurable reduction or complete suppression to achieve the desired result.

[0022] When used in the specification and / or claims, the term "effective" means sufficient to achieve the desired, anticipated, or predetermined result.

[0023] When used in conjunction with "comprising," "including," "containing," or "having" in the claims and description, the word "a" or "an" may mean "a," but it also has the same meaning as "one or more," "at least one," and "one or more than one."

[0024] The term "and / or" means both "and" and "or". For clarity, A, B, and / or C includes: only A, only B, only C, combinations of A and B, combinations of A and C, combinations of B and C, or combinations of A, B, and C. In other words, "and / or" operates on the principle of inclusion or substitution.

[0025] The words “contains” (and any form of inclusion, such as “contains” and “containing”), “have” (and any form of having, such as “have” and “possess”), “includes” (and any form of inclusion, such as “includes” and “encompasses”), or “contains” (and any form of containing, such as “includes” and “includes”) are inclusive or open-ended and do not exclude other elements or method steps not cited.

[0026] The methods and systems of the present invention may “comprising” the specific ingredients, components, compositions, etc. disclosed in the specification, “consistently composed of” the specific ingredients, components, compositions, etc. disclosed in the specification, or “composed of” the specific ingredients, components, compositions, etc. disclosed in the specification. In a non-limiting aspect, regarding the transitional phrase “based on being composed of”, the essential and novel feature of the methods and systems of the present invention is their ability to purify 1-hexene and separate 2-ethyl-1-butene, which has a similar boiling point to 1-hexene.

[0027] In the context of this invention, at least twenty embodiments will now be described. Embodiment 1 is a method for purifying 1-hexene. The method comprises the following steps: contacting a first stream containing 1-hexene and 2-ethyl-1-butene with an isomerization catalyst, said isomerization catalyst comprising modified alumina, silica-alumina, zeolite, or ion exchange resin, or any combination thereof, under conditions sufficient to selectively isomerize at least a portion of 2-ethyl-1-butene to 3-methyl-2-pentene and form a second stream containing 1-hexene and 3-methyl-2-pentene; and separating the second stream into a third stream containing 1-hexene and a fourth stream containing 3-methyl-2-pentene, wherein the conversion of 2-ethyl-1-butene in the isomerization reaction is greater than 70%, and the conversion of 1-hexene in the isomerization reaction is less than 10%. Embodiment 2 is an embodiment of Embodiment 1, wherein the isomerization conditions include a temperature of 40°C to 60°C. Embodiment 3 is the method of any one of Embodiments 1 or 2, wherein the second stream is separated by distillation at a temperature of 55°C to 75°C and a pressure of 0 to 3 bar. Embodiment 4 is the method of any one of Embodiments 1 to 3, wherein the third stream contains at least 99.5% by weight of 1-hexene, for example, 99.5% to 99.8% by weight of 1-hexene. Embodiment 5 is the method of any one of Embodiments 1 to 4, wherein the first stream is obtained by a linear α-olefin process, and / or, the first stream further contains hexane and one or more other isomers of 1-hexene. Embodiment 6 is the method of any one of Embodiments 1 to 5, wherein the first stream contains 90% to 99.5% by weight of 1-hexene, 0.3% to 1.5% by weight of 2-ethyl-1-butene, optionally 0.05% to 1% by weight of hexane, and optionally 0.1% to 15% by weight of one or more other isomers of 1-hexene. Embodiment 7 is the method of any one of Embodiments 1 to 6, wherein the second stream comprises 90% to 99.5% by weight of 1-hexene, 0.05% to 0.5% by weight of 2-ethyl-1-butene, 0.3% to 1.5% by weight of 3-methyl-2-pentene, optionally 0.05% to 1% by weight of hexane, and optionally 0.1% to 1.5% by weight of one or more other isomers of 1-hexene. Embodiment 8 is the method of any one of Embodiments 1 to 7, wherein the isomerization reaction has a 2-ethyl-1-butene conversion of 80% to 99.9%, a 1-hexene conversion of less than 5%, preferably less than 2%, and / or a total 3-methyl-2-pentene selectivity of 50% to 100%. Embodiment 9 is the method of any one of Embodiments 1 to 8, wherein the modified alumina is γ-alumina and / or a mixed phase containing a modifier. Embodiment 10 is the method described in any one of Embodiments 1 to 9, wherein the zeolite is ZSM-23, ZSM-11, ZSM-5, Y zeolite, β zeolite, magnesium alkali zeolite, or any combination thereof.Embodiment 11 is the method of any one of Embodiments 1 to 10, wherein the SiO2 / Al2O3 molar ratio of the zeolite is 2 to 1000, preferably 45 to 280; and / or the zeolite is of the H type. Embodiment 12 is the method of any one of Embodiments 1 to 11, wherein the zeolite contains 10% to 90% by weight of a binder. Embodiment 13 is the method of any one of Embodiments 1 to 12, wherein the ion exchange resin contains acidic sulfonic acid groups. Embodiment 14 is the method of any one of Embodiments 1 to 13, wherein the ion exchange resin is a polystyrene-based ion exchange resin having acidic sulfonic acid groups. Embodiment 15 is the method of any one of Embodiments 1 to 14, wherein the isomerization catalyst comprises zeolite and modified alumina in a weight ratio of 10:1 to 1:10. Embodiment 16 is the method of any one of Embodiments 1 to 15, wherein the SiO2 / Al2O3 molar ratio of the zeolite is 5 to 1000. Embodiment 17 is the method of any one of Embodiments 1 to 16, wherein the SiO2 / Al2O3 molar ratio of the zeolite is 20 to 1000. Embodiment 18 is the method of any one of Embodiments 1 to 17, wherein the SiO2 / Al2O3 molar ratio of the zeolite is 45 to 280. Embodiment 19 is a method for purifying 1-hexene, the method comprising the steps of: contacting a first stream containing 1-hexene and 2-ethyl-1-butene with an isomerization catalyst, said isomerization catalyst comprising modified alumina, silica-alumina, zeolite, or ion exchange resin or any combination thereof, under conditions sufficient to selectively isomerize at least a portion of 2-ethyl-1-butene to 3-methyl-2-pentene and form a second stream containing 1-hexene and 3-methyl-2-pentene; and separating the second stream into a third stream containing 1-hexene and a fourth stream containing 3-methyl-2-pentene, wherein the conversion of 2-ethyl-1-butene in the isomerization reaction is greater than 70%, and the conversion of 1-hexene in the isomerization reaction is less than 10%, wherein said isomerization conditions include a temperature of 40°C to 100°C, a pressure of 1 bar to 10 bar, or 0.5 hours. -1 Up to 10 hours -1 The liquid hourly space velocity (LISH), or any combination thereof, is used; wherein the zeolite is ZSM-23, ZSM-11, ZSM-5, Y zeolite, β zeolite, magnesium alkali zeolite, or any combination thereof; wherein the second stream is separated by distillation at a temperature of 55°C to 75°C and / or a pressure of 0 to 3 bar. Embodiment 20 is the method of Embodiment 19, wherein the SiO2 / Al2O3 molar ratio of the zeolite is 2 to 1000, preferably 5 to 1000, or more preferably 20 to 1000, or more preferably 2 to 5. Embodiment 21 is the method of any one of Embodiments 1 to 20, wherein the zeolite is ZSM-5 or Y zeolite, or any combination thereof.

[0028] Other objects, features, and advantages of the invention will become more apparent from the following accompanying drawings, detailed description, and embodiments. However, it should be understood that while the following drawings, detailed description, and embodiments illustrate specific embodiments of the invention, they are given by way of illustration only and are not intended to be limiting. Furthermore, it is anticipated that variations and modifications within the spirit and scope of the invention will become apparent to those skilled in the art based on this detailed description. In other embodiments, features from specific embodiments may be combined with features from other embodiments. For example, a feature of one embodiment may be combined with features of any other embodiment. In other embodiments, additional features may be added to the specific embodiments described herein.

[0029] Brief description of the attached figures

[0030] The advantages of the present invention will become apparent to those skilled in the art from the following detailed description and with reference to the accompanying drawings.

[0031] Figure 1 This is a schematic diagram illustrating an example of the method for purifying 1-hexene as described below according to the present invention.

[0032] While the invention is readily adaptable to various modifications and alternatives, specific embodiments thereof are illustrated by way of example in the accompanying drawings. The drawings may not be to scale. Detailed Implementation

[0033] Solutions have been found to address at least one or more problems related to obtaining high-purity 1-hexene. In one aspect of the invention, this solution may include a method for selectively isomerizing 2-ethyl-1-butene, which has a boiling point similar to that of 1-hexene, into isomers of 1-hexene (e.g., cis-3-methyl-2-pentene and trans-3-methyl-2-pentene), and separating 1-hexene from cis-3-methyl-2-pentene and trans-3-methyl-2-pentene by distillation. As illustrated in a non-limiting manner in the examples, an example method according to the invention can produce 1-hexene with a purity of 99.6% by weight.

[0034] These and other non-limiting aspects of the invention will be discussed in further detail in the following paragraphs with reference to the accompanying drawings.

[0035] refer to Figure 1This paper describes an example of the method and system of the present invention for purifying 1-hexene. System 100 may include a reactor 110 and a separation unit 112. A first stream containing 1-hexene and 2-ethyl-1-butene may be fed into reactor 110. In reactor 110, the first stream 101 may be contacted with an isomerization catalyst (not shown) to form a second stream 102 containing 1-hexene and 3-methyl-2-pentene. The isomerization catalyst may include activated alumina, zeolite, and / or ion exchange resin. The second stream 102 may exit reactor 110 and may be fed into separation unit 112. In separation unit 112, the second stream may be separated to form a third stream containing 1-hexene and a fourth stream containing 3-methyl-2-pentene.

[0036] The isomerization catalyst can selectively isomerize 2-ethyl-1-butene in the presence of 1-hexene [and hexane and other isomers of 1-hexene (if present)] to form 3-methyl-2-pentene. Reactor 110 can be a suitable reactor, including but not limited to: fixed-bed reactor, moving-bed reactor, trickle-bed reactor, rotating-bed reactor, slurry reactor, or fluidized-bed reactor. In some aspects, reactor 110 can be a fixed-bed reactor and may include a fixed bed containing the isomerization catalyst, and the first stream 101 can travel through and / or pass through the fixed bed. In reactor 110, the first stream 101 can be contacted with the isomerization catalyst to selectively isomerize 2-ethyl-1-butene in the first stream to 3-methyl-2-pentene. In some aspects, during the isomerization reaction (i.e., the isomerization of 2-ethyl-1-butene), the temperature of the reactor bed containing the catalyst can be from 40°C to 60°C, or at least any one, equal to, or between any two of the following: 40°C, 42°C, 44°C, 46°C, 48°C, 50°C, 52°C, 54°C, 56°C, 58°C, and 60°C. In some aspects, during the isomerization reaction, the inlet pressure of reactor 110 can be from 0.5 psig to 3 psig, or at least any one, equal to, or between any two of the following: 0.5 psig, 1 psig, 1.5 psig, 2 psig, 2.5 psig, and 3 psig. The first stream may be contacted with the isomerization catalyst under the following conditions: i) a temperature of 40°C to 100°C or 40°C to 60°C, or at least one, equal to, or between any two of the following temperatures: 40°C, 42°C, 44°C, 46°C, 48°C, 50°C, 52°C, 54°C, 56°C, 58°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, and 100°C; ii) a pressure of 1 bar to 10 bar, or at least one, equal to, or between any two of the following pressures: 1 bar, 2 bar, 3 bar, 4 bar, 5 bar, 6 bar, 7 bar, 8 bar, 9 bar, and 10 bar; and / or iii) 0.5 hours. -1 Up to 10 hours -1 Liquid hourly space velocity (LHSV), or 0.5 hours -1 1 hour -1 2 hours -1 3 hours -1 4 hours -1 5 hours -1 6 hours -1 7 hours -1 8 hours -1 9 hours -1 and 10 hours -1The liquid hourly space velocity (LHSV) is at least one of, equal to, or between any two of these values, or any combination thereof. The conversion of 2-ethyl-1-butene used in the isomerization reaction can be 50% to 100%, preferably 70% to 100%, more preferably 80% to 99.9%, or at least one of, equal to, or between any two of the following: 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 97.5%, 97.6%, 97.8%, 98%, 98.5%, 99%, 99.5%, 99.7%, 99.8%, 99.9%, and 100%. The overall selectivity of 3-methyl-2-pentene in the isomerization reaction can be from 50% to 100%, or at least one, equal to, or between any two of the following: 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 99%, and 100%. During the isomerization reaction, the conversion of 1-hexene can be less than 10%, or less than 5%, or less than 3%, or less than 2.5%, or less than 2%, or less than 1.5%, or less than 1%, or less than 0.5%, for example, from 0.5% to 10%, or less than one, equal to, or between any two of the following: 0.5%, 1%, 1.5%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, and 10%. In some respects, i) the conversion of 2-ethyl-1-butene in the isomerization reaction can be greater than 70%, greater than 80%, or greater than 90%, or greater than 95%, or greater than 97%, or greater than 97.6%, or greater than 98%, or greater than 99%, and ii) the conversion of 1-hexene in the isomerization reaction can be less than 10%, or less than 5%, or less than 3%, or less than 2.5%, or less than 2%, or less than 1.5%, or less than 1%, or less than 0.5%.

[0037] Isomerization catalysts may include alumina, silica, silica-alumina, zeolite, and / or ion exchange resins. The isomerization catalyst may include at least one, any combination thereof, or all of alumina, silica, silica-alumina, zeolite, and ion exchange resin. In some aspects, the isomerization catalyst may be alumina, silica, silica-alumina, H-type or proton (H+) type zeolite, and / or ion exchange resin containing acidic sulfonic acid groups, with a modifier. In some aspects, the isomerization catalyst may be dried in air and / or an inert atmosphere (e.g., N2) and / or under a stream at a temperature of 120°C to 300°C.

[0038] In some aspects, the isomerization catalyst may include alumina. In some aspects, the alumina may be activated alumina. In some aspects, the alumina (e.g., activated alumina) may have: i) 200m 2 / g to 550m 2 / g of surface area, or 200m 2 / g、210m 2 / g、220m 2 / g、230m 2 / g、240m 2 / g、250m 2 / g、260m 2 / g、270m 2 / g、280m 2 / g、290m 2 / g、300m 2 / g、310m 2 / g、320m 2 / g、330m 2 / g、340m 2 / g, 350m 2 / g、360m 2 / g、370m 2 / g、380m 2 / g、390m 2 / g、400m 2 / g、410m 2 / g、420m 2 / g、430m 2 / g、440m 2 / g、450m 2 / g、460m 2 / g、470m 2 / g、480m 2 / g、490m 2 / g、500m 2 / g、510m 2 / g、520m 2 / g、530m 2 / g、540m 2 / g and 550m 2ii) the average particle size of shaped alumina from 1 mm to 8 mm, or the average particle size of shaped alumina from 1, 2, 3, 4, 5, 6, 7, and 8 mm, or the average particle size of shaped alumina from 0.5 to 40 kg, or the average crushing strength from 0.5, 1, 5, 10, 15, 20, 25, 30, 35, and 40 kg, or any combination thereof. In some aspects, alumina may include amorphous alumina. In some aspects, alumina may include amorphous χ and / or γ alumina. In some aspects, alumina may include amorphous γ alumina and / or mixed-phase alumina containing a modifier. Non-limiting examples of commercially available activated alumina may include SELEXSORB CD, SELEX SORB CDL, and / or the ACTISORB 100 series available from BASF.

[0039] In some aspects, the isomerization catalyst may include zeolite. In some aspects, the zeolite may be ZSM-23, ZSM-11, ZSM-5, Y zeolite, β zeolite, magnesium alkali zeolite, or any combination thereof. In some aspects, the zeolite may be in H form, for example, in an acidic form. In some aspects, the zeolite may be a shaping catalyst, for example, combined with alumina to obtain a cylindrical extruded product. In some aspects, zeolites may have: i) a structure with two-dimensional or three-dimensional channels having 10 or 12-membered annular pores; ii) a SiO2 / Al2O3 molar ratio of 2 to 1000, 5 to 1000, or 2 to 5, or 30 to 500, or 45 to 280, or a SiO2 / Al2O3 molar ratio equal to at least one of 2, 5, 20, 30, 45, 50, 70, 100, 150, 200, 250, 280, 300, 400, 500, 600, 700, 800, 900, and 1000, or between any two of these ratios, the listed ranges including the endpoints; iii) medium-sized and / or large-sized pores; and / or iv) 300 μm 2 / g to 900m 2 / g surface area, or 300, 350, 400, 425, 450, 475, 500, 550, 600, 650, 700, 720, 740, 760, 780, 800, 850 and 900m 2The zeolite may contain at least one, equal to, or between any two of the following surface areas: 10% to 90% by weight, or 10% to 80% by weight of alumina as a binder, or 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, and 90% by weight of alumina as a binder, such as alumina, modified alumina, clay, silica-alumina, metal oxides, or any combination thereof. In certain aspects, the zeolite may contain 10% to 90% by weight, or 10% to 80% by weight of modified alumina as a binder. In certain aspects, the zeolite may be ZSM-5. In some specific aspects, the zeolite can be an H-type ZSM-5 extrusion with a SiO2 / Al2O3 molar ratio of 45 to 280 and containing 15% to 25% by weight of modified alumina as a binder. Non-limiting examples of commercially available zeolites that may be used include CBV2314, CBV5524G, CBV8014, CBV28014G, CP914C, CB V720, CB V760, or any combination thereof from Zeolyst.

[0040] In some aspects, the ion exchange resin may contain acidic sulfonic acid groups. In some specific aspects, the ion exchange resin may be a polystyrene-based ion exchange resin containing acidic sulfonic acid groups. In some specific aspects, the ion exchange resin may be an acidic cation exchange resin having a macroporous polystyrene matrix and sulfonic acid functional groups. In some specific aspects, the ion exchange resin may be an acidic cation exchange resin having macroporous styrene-divinylphenyl and sulfonic acid functional groups. In some aspects, the ion exchange resin may be in the form of hydrogen. In some aspects, the ion exchange resin may have: i) 10m 2 / g to 100m 2 / g of surface area, or 10m 2 / g、20m 2 / g、30m 2 / g、40m 2 / g, 50m 2 / g、60m 2 / g、70m 2 / g、80m 2 / g、90m 2 / g and 100m 2ii) Surface area of ​​at least one of / g, equal to any one of them, or between any two of them to The average aperture, or 200, 250, 300, 350, 400, 450 and The average pore size is equal to at least one of the following, or between any two of them: (iii) an average pore volume of 0.1 ml / g to 1 ml / g, or an average pore volume of at least one of 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 and 1 ml / g, or between any two of them: (iii) an average pore volume of 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 and 1 ml / g, or any combination thereof. Surface area, average pore size, and pore volume can be measured by nitrogen BET. Non-limiting examples of commercially available ion exchange resins that may be used include: DOW AMBERLYST 15, DOW AMBERLYST 35, DOWCSP-3, PUROLITE CT-175, PUROLITE CT-275, LANXESS K-2620, LANXESS K-2629, SINOCATA S-600, or any combination thereof, available from Purolite Co., Ltd.

[0041] In some aspects, the isomerization catalyst may include a zeolite catalyst and an alumina catalyst. The zeolite catalyst may include the zeolite described herein. The alumina catalyst may include the alumina described herein. In some specific aspects, the isomerization catalyst may comprise a mixture containing a zeolite catalyst and an alumina catalyst in a weight ratio of 10:1 to 1:10, or at least any one, equal to, or between any two of the following: 10:1, 9:2, 8:3, 7:4, 6:5, 5:5, 5:6, 4:7, 8:3, 9:2, and 10:1. In some specific aspects, the alumina catalyst may include alumina containing a modifier. In some aspects, the isomerization catalyst may include an ion exchange resin catalyst and an alumina catalyst. The ion exchange resin catalyst may include the ion exchange resin catalyst described herein. In some aspects, the isomerization catalyst may comprise a mixture containing an ion exchange resin catalyst and an alumina catalyst in a weight ratio of 10:1 to 1:10, or at least any one, equal to any one, or between any two of the following: 10:1, 9:2, 8:3, 7:4, 6:5, 5:5, 5:6, 4:7, 8:3, 9:2, and 10:1. In some aspects, the alumina catalyst may comprise alumina containing a modifier. In some aspects, the isomerization catalyst may comprise an ion exchange resin catalyst and a zeolite catalyst. In some aspects, the isomerization catalyst may comprise a mixture containing an ion exchange resin catalyst and a zeolite catalyst in a weight ratio of 10:1 to 1:10, or at least any one, equal to any one, or between any two of the following: 10:1, 9:2, 8:3, 7:4, 6:5, 5:5, 5:6, 4:7, 8:3, 9:2, and 10:1.

[0042] Table 1: Non-limiting list of catalysts

[0043]

[0044] Table 1 (continued): Non-limiting list of catalysts

[0045]

[0046] Table 1 (continued): Non-limiting list of catalysts

[0047]

[0048] In some aspects, the activity of the catalyst decreases over time due to the deposition of carbon material or pore blockage, and reactant molecules may be unable to access the active sites of the catalyst; thus, the catalyst in the reactor is referred to as a spent catalyst or a deactivated catalyst. In some aspects, the spent isomerized catalyst can be regenerated by contacting it with nitrogen (N2) or diluted oxygen (O2) at 150°C to 500°C. In some aspects, the spent catalyst can be contacted with a nitrogen (N2) stream at 150°C to 350°C, preferably 270°C to 290°C, for 15 to 30 hours. Regeneration conditions may depend on the catalyst type (e.g., composition).

[0049] Separation unit 112 may include a distillation column. The second stream 102 can be separated by distillation in the distillation column to form a third stream 103 containing 1-hexene and a fourth stream 104 containing 3-methyl-2-pentene. Operating conditions for the distillation column used to separate the second stream 102 may include: i) a temperature of 50°C to 100°C, or 55°C to 75°C, or at least one, equal to, or between any two of the following temperatures: 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, and 100°C; ii) a pressure of 0 bar to 3 bar, or at least one, equal to, or between any two of the following pressures: 0 bar, 0.01 bar, 0.1 bar, 0.5 bar, 1 bar, 1.5 bar, 2 bar, 2.5 bar, and 3 bar. The boiling points of cis-3-methyl-2-pentene and trans-3-methyl-2-pentene differ sufficiently from those of 1-hexene to allow for separation of 3-methyl-2-pentene from 1-hexane via a second distillation stream. In some respects, the third stream 103 may form the top distillate of the distillation column, while the fourth stream 104 may form the bottom distillate of the distillation column.

[0050] First stream 101 can be obtained by an α-olefin process. The α-olefin process is a process encompassing the full range of linear α-olefins and / or targeting 1-hexene. The α-olefin process may include the trimerization of ethylene to form 1-hexene. Ethylene can be trimerized using suitable processes and catalysts known in the art. In some aspects, the 1-hexene obtained by ethylene trimerization can be purified through one or more steps to obtain the first stream. The first stream may comprise i) 90% to 99.5% by weight, or 95% to 99.5% by weight, or 90, 90.5, 91, 91.5, 92, 92.5, 93, 93.5, 94, 94.5, 95, 95.5, 96, 96.5, 97, 97.5, 98, 98.5, 99, and 99.5% by weight, equal to any one of them, or between any two of them; and 0.3% to 1.5% by weight, or 0.3, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, and 1.5% by weight, equal to any one of them, or between any two of them, 2-ethyl-1-butene. First stream 101 may optionally contain 0.05% to 1% by weight of hexane and 0.1% to 1.5% by weight of one or more other isomers of 1-hexene. In some aspects, one or more other isomers of 1-hexene may include cis-2-hexene, trans-2-hexene, cis-3-hexene, and / or trans-3-hexene. 2-Ethyl-1-butene, hexane, and one or more other isomers in first stream 101 may be formed as byproducts in α-olefin processes.

[0051] The second stream 102 may contain i) 90% to 99.5% by weight, or 95% to 99.5% by weight, or at least one, equal to, or between any two of the following: 90, 90.5, 91, 91.5, 92, 92.5, 93, 93.5, 94, 94.5, 95, 95.5, 96, 96.5, 97, 97.5, 98, 98.5, 99, and 99.5% by weight; ii) 0.05% to 0.5% by weight, or 0.05, 0.1%,... 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, and 0.5 wt% of 2-ethyl-1-butene, equal to any one of them, or between any two of them; and iii) 0.3 wt% to 1.5 wt% of 3-methyl-2-pentene, or 0.3, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, and 1.5 wt% of 3-methyl-2-pentene. At least a portion of the 2-ethyl-1-butene from the first stream can be isomerized in reactor 110 to form at least a portion of the 3-methyl-2-pentene in the second stream 102. The second stream 102 may optionally contain one or more other isomers of hexane (0.05 wt% to 1 wt%) and 1-hexene (0.1 wt% to 1.5 wt%).

[0052] The third stream 103 may contain at least 99.5% by weight, or 99.5% to 99.9% by weight, or 99.5% to 99.8% by weight of 1-hexene, or at least one, equal to, or between any two of 99.5%, 99.6%, 99.7%, 99.8%, and 99.9% by weight of 1-hexene. Impurities in the third stream 103 may be less than 0.5% by weight, or less than 0.4% by weight, or less than 0.3% by weight, or less than 0.2% by weight, or less than 0.1% by weight, or 0 to 0.5% by weight or 0.1% to 0.5% by weight. Impurities in the third stream 103 may include 2-ethyl-1-butene, hexane, 3-methyl-2-pentene, and one or more other isomers. In some aspects, the third stream may also contain 0 to 0.3 wt% of 2-ethyl-1-butene, 0 to 0.3 wt% of 3-methyl-2-pentene, 0 to 0.3 wt% of one or more other isomers, and 0 to 0.1 wt% of hexane. In some aspects, 1-hexene from the third stream 103 can be used to produce HDPE and LLDPE.

[0053] The fourth stream 104 may contain at least a portion of other isomers, as well as hexane (if present) from the second stream 102. In some aspects, the fourth stream 104 may also contain a portion of 1-hexene from the second stream.

[0054] exist Figure 1 In this context, the reactor, unit, and / or region may include one or more heating and / or cooling devices (e.g., insulation, electric heaters, jacketed heat exchangers in the walls) and / or controllers (e.g., computers, flow valves, automated values, etc.) for controlling the reaction temperature and pressure of the reaction mixture. Although only one unit or region is shown, it should be understood that multiple reactors or regions may be housed in one unit, or multiple reactors may be housed in one heat transfer unit.

[0055] Example

[0056] This invention will be described in more detail through specific embodiments. The following embodiments are provided for illustrative purposes only and are not intended to limit the invention in any way. Those skilled in the art will readily recognize various non-critical parameters that can be changed or modified to produce substantially the same results.

[0057] Example 1

[0058] Methods for purifying 1-hexene

[0059] According to one embodiment of the invention, 1-hexene obtained from an α-olefin process (e.g., ethylene trimerization) is purified. A stream containing 1-hexene and 2-ethyl-1-butene (stream 1, from the ethylene trimerization process) is fed into a reactor. The reactor contains an isomerization catalyst comprising SELEXSORB CD, H-type ZSM-5 (SiO2 / Al2O3 ratio of 50), and AMBERLYST 15. In the reactor, stream 1 is contacted with the isomerization catalyst at 60°C to selectively isomerize 2-ethyl-1-butene, forming cis-3-methyl-2-pentene and trans-3-methyl-2-pentene. A stream 2 containing 1-hexene formed in the reactor, as well as cis-3-methyl-2-pentene and trans-3-methyl-2-pentene, is fed into a distillation column. Stream 2 is distilled in the distillation column. A stream containing 99.6% by weight of high-purity 1-hexene, i.e., stream 3, is obtained from the distillation column as the top distillate. A stream containing cis-3-methyl-2-pentene and trans-3-methyl-2-pentene, i.e., stream 4, was obtained from the distillation column as the bottom distillate. The compositions of streams 1, 2, 3, and 4 are provided in Table 2.

[0060] Table 2

[0061]

[0062] Example 2

[0063] Isomerization of 2-ethyl-1-butene

[0064] The catalyst used in Example 2 was tested using a stainless steel tubular flow reactor with a 1-hexene feed containing 2-ethyl-1-butene (see feed composition in Table 3). For each test, 7.00 ml of catalyst (20-40 mesh) was loaded into the reactor and dried overnight at 150°C under N2 flow. The 1-hexene feed was introduced at 1.0 ml / min, and the reactor effluent was analyzed to determine the conversion of 2-ethyl-1-butene and 1-hexene. Test data obtained after approximately 3 hours of operation are shown in Table 3. Using the catalyst described in Table 3, 2-ethyl-1-butane from the feed containing 1-hexene and 2-ethyl-1-butene was isomerized to form cis-3-methyl-2-pentene and trans-3-methyl-2-pentene. The reaction conditions and results of the experiments are described in Table 3. As shown in Table 3, zeolite and ion exchange resin catalysts can achieve a 2-ethyl-1-butene conversion rate higher than 97%. Furthermore, the alumina catalyst (Experiment 8) yielded a 2-ethyl-1-butene conversion rate of 94.55%.

[0065] Table 3

[0066]

[0067]

[0068] Table 3 (continued)

[0069]

[0070]

[0071] Although embodiments of the invention and their advantages have been described in detail, it should be understood that various changes, substitutions, and modifications can be made to this document without departing from the spirit and scope of the embodiments as defined by the appended claims. Furthermore, the scope of this application is not intended to be limited to the specific embodiments of the forms, means, methods, and steps described herein, including processes, machines, manufactures, and compositions. Those skilled in the art will readily understand from the content of this disclosure that existing or subsequently developed substances, means, methods, or steps that perform substantially the same function or achieve substantially the same results as the corresponding embodiments described herein may be used. Therefore, the appended claims are intended to include the forms, means, methods, or steps, processes, machines, manufactures, and compositions within their scope.

Claims

1. A method for purifying 1-hexene, the method comprising: Under conditions sufficient to selectively isomerize at least a portion of 2-ethyl-1-butene to 3-methyl-2-pentene and form a second stream containing 1-hexene and 3-methyl-2-pentene, a first stream containing 1-hexene and 2-ethyl-1-butene is contacted with an isomerization catalyst comprising a surface area of ​​200 m². 2 / g to 500m 2 / g of active alumina; as well as The second stream is separated into a third stream containing 1-hexene and a fourth stream containing 3-methyl-2-pentene. The isomerization reaction yielded a 2-ethyl-1-butene conversion of greater than 70%, while the isomerization reaction yielded a 1-hexene conversion of less than 10%. The isomerization conditions include a temperature of 40°C to 100°C, a pressure of 1 bar to 10 bar, or 0.5 hours. -1 Up to 10 hours -1 The liquid hourly space velocity; and The second stream is separated by distillation at a temperature of 55°C to 75°C and / or a pressure of 0 to 3 bar.

2. The method as described in claim 1, wherein, Isomerization conditions include temperatures ranging from 40°C to 60°C.

3. The method as described in claim 1, wherein, The third stream contains at least 99.5% by weight of 1-hexene.

4. The method of claim 3, wherein, The third stream contains 99.5% to 99.8% by weight of 1-hexene.

5. The method of claim 1, wherein, The first stream is obtained by a linear α-olefin process, and / or, wherein the first stream further comprises hexane and one or more other isomers of 1-hexene.

6. The method of claim 1, wherein, The first fraction comprises 90% to 99.5% by weight of 1-hexene, 0.3% to 1.5% by weight of 2-ethyl-1-butene, optionally 0.05% to 1% by weight of hexane, and optionally 0.1% to 15% by weight of one or more other isomers of 1-hexene.

7. The method of claim 1, wherein, The second stream comprises 90% to 99.5% by weight of 1-hexene, 0.05% to 0.5% by weight of 2-ethyl-1-butene, 0.3% to 1.5% by weight of 3-methyl-2-pentene, optionally 0.05% to 1% by weight of hexane, and optionally 0.1% to 1.5% by weight of one or more other isomers of 1-hexene.

8. The method of claim 1, wherein, The isomerization reaction has a 2-ethyl-1-butene conversion of 80% to 99.9%, a 1-hexene conversion of less than 5%, and / or a total 3-methyl-2-pentene selectivity of 50% to 100%.

9. The method of claim 8, wherein, The isomerization reaction has a 1-hexene conversion rate of less than 2%.

10. The method of claim 1, wherein, The average particle size of the activated alumina is 1 mm to 8 mm, and / or the average crushing strength is 0.5 to 40 kg.

11. The method according to any one of claims 1 to 10, wherein, Isomerization catalysts also include zeolites.

12. The method of claim 11, wherein, The SiO2 / Al2O3 molar ratio of zeolite is 5 to 1000.

13. The method of claim 11, wherein, The SiO2 / Al2O3 molar ratio of zeolite ranges from 20 to 1000.

14. The method of claim 11, wherein, The SiO2 / Al2O3 molar ratio of zeolite ranges from 45 to 280.

15. The method of claim 1, wherein, Activated alumina contains acidic modifiers.

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