Combined preparation of at least butene and octene from ethene

• US 10,647,630 B2
• Filed: 01/19/2016
• Issued: 05/12/2020
• Est. Priority Date: 01/19/2015
• Status: Active Grant

• Current Assignee: Evonik Oxeno GmbH & Company KG
• Original Assignee: Evonik Operations GmbH (Rag-Stiftung)
• Inventors: Stochniol, Guido, Peitz, Stephan, Maschmeyer, Dietrich, Reeker, Helene, Schallenberg, Joerg
• Primary Examiner(s): Fadhel, Ali Z
• Application Number:
  US15/000,837
• Publication Number:
  US 20160207849A1
• Time in Patent Office: 1,575 Days
• Field of Search: None
• CPC Class Codes: C07C 11/02 Alkenes
• CPC Class Codes: C07C 11/08 with four carbon atoms
• CPC Class Codes: C07C 11/107 with six carbon atoms
• CPC Class Codes: C07C 2/10 with metal oxides
• CPC Class Codes: C07C 2/24 with metals
• CPC Class Codes: C07C 2521/12 Silica and alumina
• CPC Class Codes: C07C 2523/755 Nickel
• CPC Class Codes: C07C 7/04 by distillation

Abstract

A process for the combined preparation of at least butene and octene from ethane, proceeds by a) providing an inert solvent having a boiling point or boiling range below the boiling point of butene; b) providing a first feed mixture comprising at least the inert solvent and ethene dissolved therein; c) converting the first feed mixture in a first synthesis; d) in the first synthesis, oligomerizing at least a portion of the ethene present in the first feed mixture in the presence of a first heterogeneous catalyst and in the presence of the inert solvent to obtain a first reaction mixture comprising at least the inert solvent, butene, hexene and octene; e) working-up of the first reaction mixture and/or a substance stream based thereon into a low boiler fraction comprising the inert solvent, at least one C₄-fraction comprising butenes, a C₆-fraction comprising hexenes, a C₈-fraction comprising octenes and into a C₈₊-fraction comprising hydrocarbons having more than eight carbon atoms; f) using at least a portion of the low boiler fraction for providing the first feed mixture; g) providing a second feed mixture comprising at least hexene and ethene dissolved in the hexene using at least a portion of the C₆-fraction; h) converting the second feed mixture in a second synthesis, wherein the second synthesis is spatially separated from the first synthesis; i) in the second synthesis, reacting at least a portion of the ethene present in the second feed mixture with at least a portion of the hexene present in the second feed mixture in the presence of a second heterogeneous catalyst to obtain a second reaction mixture comprising at least octene; and k) joint working-up of the second reaction mixture with the first reaction mixture or with the substance stream based thereon.

Claims

1. A process for the combined preparation of at least butene and octene from ethene, the process comprising:

a) providing an inert solvent;

b) mixing ethene having a purity of more than 99.9% and said inert solvent to provide a first feed mixture comprising said inert solvent and ethene dissolved therein;

c) in a first synthesis, oligomerizing at least a portion of the ethene present in the first feed mixture in the presence of a first heterogeneous catalyst to obtain a first reaction mixture comprising said inert solvent, butenes, hexenes and octenes;

d) working-up of the first reaction mixture and/or a stream based thereon into a low boiler fraction comprising the inert solvent, at least one C₄-fraction comprising butenes, a C₆-fraction comprising hexenes, a C₈-fraction comprising octenes and into a C₈₊-fraction comprising hydrocarbons having more than eight carbon atoms;

e) recycling at least a portion of the low boiler fraction to the first feed mixture;

f) mixing hexene and ethene to provide a second feed mixture comprising ethene dissolved in the hexene wherein hexene is provided using at least a portion of the C₆-fraction;

g) in a second synthesis, reacting at least a portion of the ethene present in the second feed mixture with at least a portion of the hexene present in the second feed mixture in the presence of a second heterogeneous catalyst to obtain a second reaction mixture comprising at least octene, wherein the second synthesis is spatially separated from the first synthesis; and

h) feeding the second reaction mixture to the working-up of said first reaction mixture;

wherein said inert solvent has a boiling point or boiling range below any butene formed in said first synthesis;

a solid is used as the first heterogenous catalyst and/or the second heterogenous catalyst which comprises at least two components,

wherein a first component comprises at least one element selected from the group consisting of Ni, Cr, Fe, and Ti, which is present in a metallic and/or oxidic and/or hydridic form, and

wherein a second component comprises at least one metal oxide selected from the group consisting of Al₂O₃, SiO₂, TiO₂, and ZrO₂ and mixtures thereof.

2. The process according to claim 1, wherein the low boiler fraction is separated at the top from the first reaction mixture or from the substance stream based on the first reaction mixture using a first distillation column to obtain an essentially solvent-free bottom product from which in turn the C₄-fraction, the C₆-fraction, the C₈-fraction and the C₈₊-fraction are separated.

3. The process according to claim 2, wherein the low boiler fraction in the first synthesis and/or in the second synthesis comprises unreacted ethene in addition to said inert solvent.

4. The process according to claim 1, wherein said inert solvent is propane or isobutane or a mixture thereof.

5. The process according to claim 1 said first synthesis is carried out at the following conditions with the provision that said inert solvent is present in a liquid phase in said oligomerizing:

Temperature;

20°

C. to 150°

C.,

Pressure;

1*10⁵ Pa to 50*10⁵ Pa,

Weight hourly space velocity;

3 to 50 h<sup>−

1</sup>, and

a molar ratio of ethene to said solvent in the first feed mixture is adjusted to a value of 0.1 to 0.5.

6. The process according to claim 5, wherein the ethene is completely dissolved in the liquid inert solvent at the first synthesis conditions.

7. The process according to claim 5, wherein the ethene is partially dissolved in the liquid inert solvent and is present partially in the gas phase at the first synthesis conditions.

8. The process according to claim 1, wherein the second feed mixture comprises ethene at a proportion of from 0.1% by weight to 30% by weight and wherein the second synthesis is carried out at a temperature of from 20°

C. to 150°

C. and at a pressure of from 1*10⁵ Pa to 50*10⁵ Pa, wherein the proportion of ethene in the second feed mixture and the reaction conditions of the second synthesis are selected so that the hexene is present in a liquid phase and the ethene is completely dissolved therein.

9. The process according to claim 1, wherein the second reaction mixture is provided exclusively using at least a portion of the C₆-fraction and by adding ethene.

10. The process according to claim 9, wherein the second reaction mixture is provided exclusively using a first portion of the C₆-fraction and by adding ethene and that a second portion of the C₆-fraction is discharged.

11. The process according to claim 9, wherein the second reaction mixture is provided exclusively using the entire C₆-fraction and by adding ethene.

12. The process of claim 1, wherein said first reaction mixture further comprises ethene and said low boiler fraction comprises ethene and said inert solvent.

13. The process of claim 1, further comprising discharging the first reaction mixture from a reactor with said inert solvent as a transport medium after the first synthesis.

14. A process for the combined preparation of at least butene and octene from ethene, the process comprising:

a) providing an inert solvent;

b) mixing ethene having a purity of more than 99.9% and said inert solvent to provide a first feed mixture comprising said inert solvent and ethene dissolved therein;

c) in a first synthesis, oligomerizing at least a portion of the ethene present in the first feed mixture in the presence of a first heterogeneous catalyst to obtain a first reaction mixture comprising said inert solvent, butenes, hexenes and octenes;

d) working-up of the first reaction mixture and/or a stream based thereon into a low boiler fraction comprising the inert solvent, at least one C₄-fraction comprising butenes, a C₆-fraction comprising hexenes, a C₈-fraction comprising octenes and into a C₈₊-fraction comprising hydrocarbons having more than eight carbon atoms;

e) recycling at least a portion of the low boiler fraction to the first feed mixture;

f) mixing hexene and ethene to provide a second feed mixture comprising ethene dissolved in the hexene wherein hexene is provided using at least a portion of the C₆-fraction;

g) in a second synthesis, reacting at least a portion of the ethene present in the second feed mixture with at least a portion of the hexene present in the second feed mixture in the presence of a second heterogeneous catalyst to obtain a second reaction mixture comprising at least octene, wherein the second synthesis is spatially separated from the first synthesis; and

h) feeding the second reaction mixture to the working-up of said first reaction mixture;

wherein said inert solvent has a boiling point or boiling range below any butene formed in said first synthesis;

a solid is used as the first heterogenous catalyst which comprises at least two components,

wherein a first component comprises at least one element selected from the group consisting of Ni, Cr, Fe, and Ti, which is present in a metallic and/or oxidic and/or hydridic form, and

wherein a second component comprises at least one metal oxide selected from the group consisting of Al₂O₃, SiO₂, TiO₂, and ZrO₂ and mixtures thereof.

15. The process of claim 14, wherein a solid is used as the second heterogenous catalyst which comprises at least two components,

wherein a first component of said second heterogeneous catalyst comprises at least one element selected from the group consisting of Ni, Cr, Fe, and Ti, which is present in a metallic and/or oxidic and/or hydridic form, and

wherein a second component of said second heterogeneous catalyst comprises at least one metal oxide selected from the group consisting of Al₂O₃, SiO₂, TiO₂, and ZrO₂ and mixtures thereof.

16. The process of claim 14, further comprising discharging the first reaction mixture from a reactor with said inert solvent as a transport medium after the first synthesis.

17. The process of claim 14, wherein said first reaction mixture further comprises ethene and said low boiler fraction comprises ethene and said inert solvent.