Processes for preparing isoprene and mono-olefins comprising at least six carbon atoms

Patent metadata

Field	Value
Publication number	US-11976017-B2
Application number	US-202017755724-A
Country	US
Kind code	B2
Filing date	Nov 11, 2020
Priority date	Dec 19, 2019
Publication date	May 7, 2024
Grant date	May 7, 2024

Abstract

The present invention relates to processes for preparing isoprene and mono-olefins comprising at least six carbon atoms. In one aspect, a process comprises (a) hydroformylating a mixed C4 olefin stream, wherein the mixed C4 olefin stream comprises 1-butene, 2-butene, and optionally isobutene, with a hydroformylation catalyst, wherein the hydroformylation catalyst comprises rhodium with monodentate organophosphorous ligand and optionally polydentate organophosphorous ligand, to produce a mixture comprising linear and branched C5 aldehydes; (b) separating the branched C5 aldehydes from the linear C5 aldehydes to provide a branched C5 aldehyde stream and a linear C5 aldehyde stream; (c) dehydrating the branched C5 aldehydes in the branched C5 aldehyde stream using a dehydration catalyst to form a stream comprising isoprene; (d) hydrogenating the linear C5 aldehydes in the linear C5 aldehyde stream to form a C5 alcohol stream; (e) dehydrating the C5 alcohols in the C5 alcohol stream with a second dehydration catalyst to form a C5 olefin stream; (f) hydroformylating the C5 olefins in the C5 olefin stream to generate a C6 aldehyde stream; (g) hydrogenating the C6 aldehydes in the C6 aldehyde stream to form a C6 alcohol stream; and (h) dehydrating the C6 alcohols in the C6 alcohol stream with a third dehydration catalyst to form a C6 olefin stream.

First claim

What is claimed is:

1. A process for preparing isoprene and mono-olefins comprising at least six carbon atoms, the process comprising:
(a) hydroformylating a mixed C4 olefin stream, wherein the mixed C4 olefin stream comprises 1-butene, 2-butene, and optionally isobutene, with a hydroformylation catalyst, wherein the hydroformylation catalyst comprises rhodium with monodentate organophosphorous ligand and optionally polydentate organophosphorous ligand, to produce a mixture comprising linear and branched C5 aldehydes;
(b) separating the branched C5 aldehydes from the linear C5 aldehydes to provide a branched C5 aldehyde stream and a linear C5 aldehyde stream;
(c) dehydrating the branched C5 aldehydes in the branched C5 aldehyde stream using a dehydration catalyst to form a stream comprising isoprene;
(d) hydrogenating the linear C5 aldehydes in the linear C5 aldehyde stream to form a C5 alcohol stream;
(e) dehydrating the C5 alcohols in the C5 alcohol stream with a second dehydration catalyst to form a C5 olefin stream;
(f) hydroformylating the C5 olefins in the C5 olefin stream to generate a C6 aldehyde stream;
(g) hydrogenating the C6 aldehydes in the C6 aldehyde stream to form a C6 alcohol stream; and
(h) dehydrating the C6 alcohols in the C6 alcohol stream with a third dehydration catalyst to form a C6 olefin stream.

2. The process of claim 1 , wherein the ratio of linear and branched C5 aldehydes produced in step (a) is adjusted to match a target ratio of isoprenes and C6 olefins in steps (c) and (h), respectively.

3. The process of claim 2 , wherein the hydroformylation catalyst comprises a polydentate organophosphorous ligand, and the ratio of polydentate organophosphorous ligand to rhodium is less than 1:1.

4. The process of claim 3 , wherein the hydroformylation in step (a) is conducted in one more reaction zones, and wherein the ratio of linear to branched C5 aldehydes in the mixture of step (a) is increased by increasing the ratio of polydentate organophosphorus ligand to rhodium in at least one reaction zone.

5. The process of claim 2 , wherein the hydroformylation in step (a) comprises contacting the mixed C4 olefin stream with synthesis gas and the hydroformylation catalyst, the contacting conducted at hydroformylation conditions comprising a synthesis gas partial pressure, and wherein the ratio of linear to branched C5 aldehydes in the mixture of step (a) is increased by decreasing the synthesis gas partial pressure.

6. The process of claim 2 , wherein the hydroformylation in step (a) comprises contacting the mixed C4 olefin stream with synthesis gas and the hydroformylation catalyst, the contacting conducted in first and subsequent reaction zones and at hydroformylation conditions comprising a mixed C4 olefin partial pressure, wherein the ratio of linear to branched C5 aldehydes in the mixture of step (a) is increased by increasing the mixed C4 olefin partial pressure in the first reaction zone.

7. The process of claim 2 , wherein the hydroformylation in step (a) is conducted in one or more reaction zones, and wherein the ratio of linear to branched C5 aldehydes in the mixture of step (a) is increased by increasing the transition metal concentration in at least one reaction zone.

8. The process of claim 1 , wherein the C5 olefin stream further comprises C5 alcohols and ethers, and further comprising separating the C5 alcohols and ethers from the C5 olefin stream and returning the separated C5 alcohols and ethers to dehydration step (e).

9. The process of claim 1 , wherein the hydroformylation in step (f) is conducted in the same reactor or plurality of reactors as the hydroformylation in step (a).

10. The process of claim 1 , wherein the target ratio of isoprene from step (c) relative to C6 olefin produced from step (h) is from 1:1 to 1:50.

11. The process of claim 1 , wherein the C5 olefin stream comprises linear C5 alpha olefins, linear C5 internal olefins, and branched C5 olefins.

12. The process of claim 1 , further comprising adjusting the composition of the mixed C4 olefin stream prior to step (a).

13. The process of claim 1 , further comprising:
(i) hydroformylating the C6 olefins in the C6 olefin stream to generate a C7 aldehyde stream;
(j) hydrogenating the C7 aldehydes in the C7 aldehyde stream to form a C7 alcohol stream; and
(k) dehydrating the C7 alcohols in the C7 alcohol stream with a fourth dehydration catalyst to form a C7 olefin stream.

14. The process of claim 13 further comprising:
(l) hydroformylating the C7 olefins in the C7 olefin stream to generate a C8 aldehyde stream;
(m) hydrogenating the C8 aldehydes in the C8 aldehyde stream to form a C8 alcohol stream; and
(n) dehydrating the C8 alcohols in the C8 alcohol stream with a fifth dehydration catalyst to form a C8 olefin stream.

15. The process of claim 1 , wherein the monodentate organophosphosphorous ligand is a monophosphite, and wherein the hydroformylation catalyst further comprises polydentate organophosphorous ligand, and wherein the polydentate organophosphorous ligand is a bisphosphite.

Assignees

• Dow Technology Investments Llc

Inventors

• Bigi Marinus A
• Brammer Michael A
• Miller Glenn A
• Singh Amarnath

Classifications

• C07C1/24 Primary

  by elimination of water · CPC title

• C07C45/50

  by oxo-reactions · CPC title

• C07C45/82

  by distillation · CPC title

• C07C29/141

  with hydrogen or hydrogen-containing gases · CPC title

• Y02P20/582

  Recycling of unreacted starting or intermediate materials · CPC title