阅读说明：本技术 用于异戊二烯纯化的系统和方法 (Systems and methods for isoprene purification ) 是由 欧内斯托·沃哈拉 于 2018-04-12 设计创作，主要内容包括：在包含异戊二烯的产物流中选择性氢化炔属化合物的方法。在异戊二烯存在下选择性氢化炔烃的方法可包括获得包含炔烃、异戊二烯和丁二烯或环戊二烯或两者的烃混合物。如果存在环戊二烯,则烃混合物可包含大于2重量％的环戊二烯。该方法还可包括在对炔烃的氢化比对异戊二烯的氢化更具选择性的反应条件下,使烃混合物和氢气(H<Sub>2</Sub>)与氢化催化剂接触。(A process for the selective hydrogenation of acetylenic compounds in a product stream comprising isoprene. A method of selectively hydrogenating alkynes in the presence of isoprene can include obtaining a hydrocarbon mixture comprising alkynes, isoprene, and butadiene or cyclopentadiene or both. If cyclopentadiene is present, the hydrocarbon mixture may comprise greater than 2 wt% cyclopentadiene. The process can also include contacting the hydrocarbon mixture and hydrogen (H2) with a hydrogenation catalyst under reaction conditions that are more selective for hydrogenation of alkynes than for hydrogenation of isoprene.)

1. A method of selectively hydrogenating an alkyne in the presence of isoprene, the method comprising:

(a) obtaining a hydrocarbon mixture comprising acetylenes, isoprene and butadiene or cyclopentadiene or both, wherein the hydrocarbon mixture comprises greater than 2 wt% cyclopentadiene, if present; and

(b) The hydrocarbon mixture and hydrogen (H2) are contacted with a hydrogenation catalyst under reaction conditions that are more selective for the hydrogenation of alkynes than for the hydrogenation of isoprene.

2. The method of claim 1, wherein the hydrogenation catalyst comprises nickel (Ni), palladium (Pd), or platinum (Pt), or a combination or alloy thereof.

3. The method of claim 1 or 2, wherein less than 10% of the isoprene is hydrogenated.

4. The process according to claim 1 or 2, wherein the alkyne is a butyne, preferably 2-butyne.

5. The method of claim 1 or 2, wherein the reaction conditions comprise a temperature of 30 ℃ to 50 ℃.

6. The process of claim 1 or 2, wherein the reaction conditions comprise a pressure of less than 10 bar (gauge), preferably from 5 bar (gauge) to 8 bar (gauge).

7. The process of claim 1 or 2, wherein the reaction conditions comprise a Weight Hourly Space Velocity (WHSV) of 1h "1 to 4 h" 1.

8. the process of claim 1 or 2, wherein the reaction conditions comprise a mole% ratio of H2/butyne of 2 to 3.

9. the process of claim 1 or 2, wherein the amount of cyclopentadiene in the hydrocarbon mixture is from 5 wt% to 25 wt%.

10. The method of claim 1 or 2, wherein the hydrocarbon mixture is a liquid.

11. The process according to claim 1 or 2, wherein the alkyne is fully hydrogenated.

12. The process of claim 1 or 2, wherein the process does not include a dimerization reaction involving cyclopentadiene.

13. the process of claim 1 or 2, wherein butadiene is added to a product stream from a pyrolysis or cracking process to form the hydrocarbon mixture.

14. The process of claim 1 or 2, wherein cyclopentadiene is added to a product stream from a pyrolysis or cracking process to form the hydrocarbon mixture.

15. The process of claim 1 or 2, wherein the contacting is carried out in a fixed bed reactor.

16. A process for the selective hydrogenation of butyne in the presence of isoprene, the process comprising:

(a) Obtaining a hydrocarbon mixture comprising butynes, isoprene, butadiene and cyclopentadiene, wherein the hydrocarbon mixture comprises 3 wt% to 25 wt% cyclopentadiene; and

(b) Contacting a hydrocarbon mixture and hydrogen (H2) with a hydrogenation catalyst comprising nickel (Ni), palladium (Pd) or platinum (Pt), or a combination or alloy thereof, at a temperature of less than 80 ℃, a pressure of less than 10 bar (gauge) and a Weight Hourly Space Velocity (WHSV) of less than 8H "1 in a fixed bed reactor under reaction conditions such that less than 7% of the isoprene is hydrogenated, wherein the molar% ratio of H2: butyne is less than 6: 1.

Technical Field

The present invention relates generally to the purification of isoprene. More specifically, the present invention relates to the selective hydrogenation of acetylenic compounds in a product stream comprising isoprene.

Background

Isoprene (CH2 ═ C (CH3) -CH ═ CH2) is an important petrochemical product. For example, it is used in the production of rubber and plastics. Isoprene is typically produced as a by-product of the hydrocarbon pyrolysis or catalytic cracking to produce ethylene. Isoprene is typically present in the product mixture during pyrolysis or catalytic processes, the product mixture also including C4 hydrocarbons and C5 hydrocarbons, the C4 and C5 hydrocarbons including acetylenic C4 and C5 hydrocarbons. These alkynes may adversely affect downstream processes. Thus, there is a need to separate the acetylenic compounds from isoprene before the isoprene can be used in other processes. However, the volatility of isoprene and other alkynes is similar. This makes separation by distillation difficult. Therefore, the extractive distillation for separating acetylenic compounds from isoprene is generally complex and expensive.

Selective hydrogenation in the presence of a noble metal-containing catalyst is one method of separating alkynes from isoprene (e.g., selective hydrogenation of vinyl acetylene for butadiene production). However, depending on how it is carried out, the selective hydrogenation process can result in a substantial loss of diolefins, such as isoprene.

Disclosure of Invention

A process has been found for the selective hydrogenation of acetylenic compounds in a product stream comprising isoprene. The process achieves operating conditions (e.g., temperature, pressure, Weight Hourly Space Velocity (WHSV)) that minimize isoprene loss during hydrogenation.

Embodiments of the invention include methods of selectively hydrogenating alkynes in the presence of isoprene. The method includes obtaining a hydrocarbon mixture comprising acetylenes, isoprene, and butadiene or cyclopentadiene or both. If cyclopentadiene is present, the hydrocarbon mixture may comprise greater than 2 wt% cyclopentadiene. Embodiments of the invention may also include contacting the hydrocarbon mixture and hydrogen (H2) with a hydrogenation catalyst under reaction conditions that are more selective for the hydrogenation of alkynes than for the hydrogenation of isoprene.

the following includes definitions of various terms and phrases used in the specification.

The term "about" or "approximately" is defined as being close as understood by one of ordinary skill in the art. 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%.

The terms "weight%", "volume%" or "mole%" refer to the weight percent, volume percent or mole percent of a component, respectively, based on the total weight, volume or total molar amount of the material comprising the component. In one non-limiting example, 10 mole of a component in 100 moles of material is 10 mole% of the component.

The term "substantially" is defined as including ranges within 10%, within 5%, within 1%, or within 0.5%.

The terms "inhibit" or "reduce" or "prevent" or "avoid" when used in the claims and/or the specification includes any measurable reduction or complete inhibition to achieve a desired result.

As used in this specification and/or in the claims, the term "effective" means suitable for achieving a desired, expected, or expected result.

When used in conjunction with the terms "comprising," including, "" containing, "or" having "in the claims or specification, the singular forms" a, "" an, "and" the "are intended to mean" one "or" an "without the use of quantity prior to the element, but it is also intended to mean" one or more, "" at least one, "and" one or more than one.

The words "comprising," "having," "including," or "containing" are inclusive or open-ended and do not exclude additional, unrecited elements or method steps.

The methods of the present invention can "comprise," "consist essentially of," or "consist of" the particular ingredients, components, compositions, etc. disclosed throughout the specification.

In the context of the present invention, at least sixteen embodiments are now described. Embodiment 1 is a process for selectively hydrogenating an alkyne in the presence of isoprene, the process comprising the steps of: (a) obtaining a hydrocarbon mixture containing acetylenes, isoprene and butadiene or cyclopentadiene or both, wherein the hydrocarbon mixture comprises greater than 2 wt% cyclopentadiene, if present; and (b) contacting the hydrocarbon mixture and hydrogen (H2) with a hydrogenation catalyst under reaction conditions that are more selective for the hydrogenation of alkynes than for the hydrogenation of isoprene. Embodiment 2 is the method of embodiment 1, wherein the hydrogenation catalyst comprises nickel (Ni), palladium (Pd), or platinum (Pt), or a combination or alloy thereof. Embodiment 3 is the method of embodiment 1 or 2, wherein less than 10% of the isoprene is hydrogenated. Embodiment 4 is the method of any one of embodiments 1 to 3, wherein the alkyne is a butyne, preferably 2-butyne. Embodiment 5 is the method of any one of embodiments 1 to 4, wherein the reaction conditions include a temperature of 30 ℃ to 50 ℃. Embodiment 6 is the method of any one of embodiments 1 to 5, wherein the reaction conditions include a pressure of less than 10 bar (gauge), preferably 5 bar (gauge) to 8 bar (gauge). Embodiment 7 is the method of any one of embodiments 1 to 6, wherein the reaction conditions include a Weight Hourly Space Velocity (WHSV) of 1h "1 to 4 h" 1. Embodiment 8 is the method of any one of embodiments 1 to 7, wherein the reaction conditions include a mole% ratio of H2/butyne of 2 to 3. Embodiment 9 is the method of any one of embodiments 1 to 8, wherein the amount of cyclopentadiene in the hydrocarbon mixture is from 5 wt% to 25 wt%. Embodiment 10 is the method of any one of embodiments 1 to 9, wherein the hydrocarbon mixture is a liquid. Embodiment 11 is the method of any one of embodiments 1 to 10, wherein the alkyne is fully hydrogenated. Embodiment 12 is the method of any one of embodiments 1 to 11, wherein the method does not include a dimerization reaction involving cyclopentadiene. Embodiment 13 is the method of any one of embodiments 1 to 12, wherein butadiene is added to the product stream from the pyrolysis or cracking process to form the hydrocarbon mixture. Embodiment 14 is the method of any one of embodiments 1 to 13, wherein cyclopentadiene is added to a product stream from a pyrolysis or cracking process to form a hydrocarbon mixture. Embodiment 15 is the method of any one of embodiments 1 to 14, wherein the contacting is conducted in a fixed bed reactor.

Brief description of the drawings

For a more complete understanding, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:

FIG. 1 shows a system for selective hydrogenation of acetylenic compounds in the presence of isoprene according to an embodiment of the present invention; and

Fig. 2 shows a process for selective hydrogenation of acetylenic compounds in the presence of isoprene according to an embodiment of the present invention.

Embodiment 16 is a process for selectively hydrogenating butynes in the presence of isoprene, the process comprising the steps of: (a) obtaining a hydrocarbon mixture comprising butynes, isoprene, butadiene and cyclopentadiene, wherein the hydrocarbon mixture comprises 3 wt% to 25 wt% cyclopentadiene; and (b) contacting the hydrocarbon mixture and hydrogen (H2) with a hydrogenation catalyst comprising nickel (Ni), palladium (Pd) or platinum (Pt), or a combination or alloy thereof, in a fixed bed reactor at a temperature of less than 80 ℃, a pressure of less than 10 bar (gauge) and a Weight Hourly Space Velocity (WHSV) of less than 8H "1 under reaction conditions such that less than 7% of the isoprene is hydrogenated, wherein the molar% ratio of H2: butyne is less than 6: 1.

Other objects, features and advantages of the present invention will become apparent from the following drawings, detailed description and examples. It should be understood, however, that the drawings, detailed description, and examples, while indicating specific embodiments of the present invention, are given by way of illustration only, and not by way of limitation. In addition, it is contemplated that variations and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. In other embodiments, features from specific embodiments may be combined with features from other embodiments. For example, features from one embodiment may be combined with features from any of the other embodiments. In other embodiments, additional features may be added to the specific embodiments described herein.