Method for producing conjugated diene

Patent metadata

Field	Value
Publication number	US-11198657-B2
Application number	US-201615577988-A
Country	US
Kind code	B2
Filing date	Jun 1, 2016
Priority date	Jun 3, 2015
Publication date	Dec 14, 2021
Grant date	Dec 14, 2021

Abstract

A method for producing a conjugated diene, including a step A of allowing an α-olefin and formaldehyde to react with each other to produce a γ,δ-unsaturated alcohol in the presence of an alcohol; and a step B of subjecting the γ,δ-unsaturated alcohol to a dehydration reaction at 135 to 210° C. in the presence of an aqueous solution of an acidic catalyst.

First claim

The invention claimed is:

1. A method for producing a conjugated diene, the method consisting of:
reacting an α-olefin and formaldehyde with each other to produce a reaction liquid comprising a γ,δ-unsaturated alcohol;
washing the reaction liquid to obtain a washed reaction liquid, wherein the washing comprises contacting the reaction liquid with an alkaline aqueous solution, and wherein the washed reaction liquid comprises an upper organic layer comprising the γ,δ-unsaturated alcohol;
separating the upper organic layer from the washed reaction liquid to obtain a separated organic layer, then;
distilling the separated organic layer to obtain a purified γ,δ-unsaturated alcohol; then
subjecting the γ,δ-unsaturated alcohol to a dehydration reaction at 135 to 210° C. in the presence of an aqueous solution of an acidic catalyst, to obtain a conjugated diene, and
optionally, purifying the conjugated diene.

2. The method according to claim 1 , wherein a solvent is present in the reacting of the α-olefin with the formaldehyde.

3. The method according to claim 2 , wherein the solvent is an alcohol.

4. The method according to claim 1 , wherein the α-olefin is isobutene, and the γ,δ-unsaturated alcohol is 3-methyl-3-buten-1-ol.

5. The method according to claim 1 , wherein the dehydration reaction comprises:
feeding the γ,δ-unsaturated alcohol and water continuously or intermittently into a reactor; and
removing the produced conjugated diene and water continuously or intermittently from the reaction system.

6. The method according to claim 5 , wherein {(feed rate of water (mol/hr))/(feed rate of γ,δ-unsaturated alcohol (mol/hr))} is from 0.5 to 12.

7. The method according to claim 1 , wherein the acidic catalyst is phosphoric acid.

8. The method according to claim 1 , wherein a reaction pressure in the dehydration reaction is from 0.35 to 1.6 MPa.

9. The method according to claim 1 , wherein, after the washing, the washed reaction liquid is an aqueous solution having a pH of 9 to 13.

Assignees

• Kuraray Co

Inventors

• Suzuki Yutaka
• Shimizu Masaki

Classifications

• C07C29/44

  increasing the number of carbon atoms by addition reactions, i.e. reactions involving at least one carbon-to-carbon double or triple bond (C07C29/16 takes precedence) · CPC title

• C07C1/24 Primary

  by elimination of water · CPC title

• C07C11/18

  Isoprene · CPC title

• C07C29/38

  by reaction with aldehydes or ketones · CPC title

• B01J27/16

  containing oxygen {, i.e. acids, anhydrides and their derivates with N, S, B or halogens without carriers or on carriers based on C, Si, Al or Zr; also salts of Si, Al and Zr} · CPC title