Production of at least 1-hexene and octene from ethene

Patent metadata

Field	Value
Publication number	US-10196327-B2
Application number	US-201715623631-A
Country	US
Kind code	B2
Filing date	Jun 15, 2017
Priority date	Jul 8, 2016
Publication date	Feb 5, 2019
Grant date	Feb 5, 2019

Abstract

The invention is concerned with the production of 1-hexene and octenes from ethene. 1-Butene is optionally also to be produced. The problem addressed by the present invention is that of developing a process for producing 1-hexene from ethene by MTHxE etherification to achieve better chemical utilization of the employed carbon atoms. This problem is solved by catalytic retrocleavage of MTHxE into the C6 olefins and the alcohol, reuse of the alcohol in the etherification and reaction of the obtained C6 olefins with ethene to afford C8 olefins. In this way the alcohol is not lost from the process but rather is internally recirculated as a derivatizing agent. The less attractive C6 olefins from the cleavage product are upgraded to octene with further ethene in order to provide a further commercial product.

First claim

The invention claimed is:

1. A process for producing at least 1-hexene and octene from ethene comprising the steps of:
a) providing a feedstock mixture comprising ethene;
b) subjecting the ethene to a first oligomerization to obtain a first oligomerizate comprising olefins having less than six carbon atoms, C 6 olefins including 1-hexene, 3-methyl-cis-2-pentene, and 3-methyl-trans-2-pentene and olefins having more than six carbon atoms;
c) distilling the first oligomerizate to obtain a C 6 fraction comprising 1-hexene, 3-methyl-cis-2-pentene, and 3-methyl-trans-2-pentene;
d) subjecting the C 6 fraction to an etherification by addition of an alcohol in the presence of a heterogeneous catalyst to obtain a first reaction mixture comprising at least 1-hexene and 3-methyl-3-methoxypentane;
e) distilling the first reaction mixture to obtain a first target fraction comprising 1-hexene and an ether fraction comprising at least 3-methyl-3-methoxypentane;
wherein the improvement comprises:

f) subjecting the ether fraction to a cleavage reaction to obtain a cleavage product which comprises 3-methyl-cis-2-pentene, 3-methyl-trans-2-pentene and the alcohol;
g) removing the alcohol from the cleavage product by distillation and reusing said removed alcohol in the etherification;
h) removing a first intermediate comprising at least 3-methyl-cis-2-pentene and 3-methyl-trans-2-pentene from the cleavage product by distillation;
i) reacting the first intermediate with ethene to obtain a second reaction mixture comprising olefins having at least eight carbon atoms; and
k) obtaining a second target fraction comprising octene from the second reaction mixture by distillation.

2. The process according to claim 1 , wherein
the first oligomerizate further comprises 1-butene, cis-2-butene and trans-2-butene and 1-butene is recovered as follows:
a) distilling the first oligomerizate to provide a C 4 fraction which comprises 1-butene, cis-2-butene and trans-2-butene;
b) separating the C 4 fraction by distillation into a third target fraction comprising 1-butene and into a second intermediate which comprises cis-2-butene and trans-2-butene;
c) subjecting the second intermediate to a second oligomerization to obtain a second oligomerizate which comprises olefins having at least eight carbon atoms;
d) distilling the second oligomerizate together with the second reaction mixture to obtain the second target fraction.

3. The process according to claim 1 , wherein the distillative workup of the first oligomerizate provides a C 6+ fraction which comprises olefins having more than six carbon atoms and in that the C 6+ fraction is worked up by distillation together with the second reaction mixture to obtain the second target fraction.

4. The process according to claim 2 , wherein the distillative workup of the first oligomerizate provides a C 6+ fraction which comprises olefins having more than six carbon atoms and in that the C 6+ fraction is worked up by distillation together with the second reaction mixture and with the second oligomerizate to obtain the second target fraction.

5. The process according to claim 1 , wherein the feedstock mixture comprises more than 95 wt % of ethene and that the reaction conditions of the first oligomerization are chosen such that the first oligomerization is affected in the gas phase in the presence of a heterogeneous catalyst.

6. The process according to claim 1 , wherein the feedstock mixture comprises less than 25 wt % of ethene, in that the feedstock mixture comprises more than 75 wt % of a solvent, wherein the reaction conditions of the first oligomerization and the concentration of the ethene in the solvent are chosen such that the first oligomerization is affected in the liquid phase and the ethene is fully dissolved in the liquid solvent.

7. The process according to claim 5 , wherein ethene unconverted in the first oligomerization is removed by distillation from the first oligomerizate and recycled into the first oligomerization.

8. The process according to claim 1 , wherein the feedstock mixture comprises not only ethene but also olefins having four carbon atoms, wherein the reaction conditions of the first oligomerization and the composition of the feedstock mixture are chosen such that the first oligomerization is affected in the liquid phase and the ethene is fully dissolved in the olefins having four carbon atoms.

9. The process according to claim 1 , wherein the feedstock mixture comprises not only ethene but also olefins having six carbon atoms, wherein the reaction conditions of the first oligomerization and the composition of the feedstock mixture are chosen such that the first oligomerization is affected in the liquid phase and the ethene is fully dissolved in the olefins having six carbon atoms.

10. The process according to claim 1 , wherein the feedstock mixture comprises not only ethene but also olefins having four carbon atoms and olefins having six carbon atoms, wherein the reaction conditions of the first oligomerization and the composition of the feedstock mixture are chosen such that the first oligomerization is affected in the liquid phase and the ethene is fully dissolved in the olefins having four and six carbon atoms.

11. The process according to claim 1 , wherein a solid body comprising at least two components is employed as a heterogeneous catalyst in one or more of the following reactions:
in the first oligomerization;
in the second oligomerization;
in the reaction of the second intermediate with ethene;
wherein the first component comprises at least one element selected from Ni, Cr, Fe, Ti which is present in metallic and/or oxidic and/or hydridic form and wherein the second component comprises at least one metal oxide selected from Al 2 O 3 , SiO 2 , TiO 2 , ZrO 2 .

12. The process according to claim 11 , wherein the reaction of the second intermediate with ethene is effected in the presence of said catalyst, wherein this reaction is affected at a temperature between 20° C. and 150° C. and at a pressure between 1*10 5 Pa and 50*10 5 Pa, wherein the quantitative ratio of the ethene to the second intermediate is chosen such that the second intermediate is present in the liquid phase and the ethene is fully dissolved therein.

13. The process according to claim 1 , wherein the cleavage reaction is effected in the gas phase at a pressure of 1*10 5 Pa to 25*10 5 Pa and a temperature of 130° C. to 350° C. in the presence of a solid body having the following composition which sums to 100 wt %:
silicon dioxide: 61 wt % to 74 wt %;
aluminum oxide: 19 wt % to 23 wt %;
magnesium oxide: 10 wt % to 12 wt %;
sum of other substances: 0 to 10 wt %.

14. The process according to claim 1 , wherein the etherification is affected in the liquid phase at a pressure of 1*10 5 Pa to 7*10 5 Pa and a temperature of 50° C. to 130° C. in the presence of a polystyrene-divinylbenzene copolymer bearing sulfonic acid groups or carboxylic acid groups.

15. The process according to claim 2 , wherein the cleavage reaction is affected in the gas phase at a pressure of 1*10 5 Pa to 25*10 5 Pa and a temperature of 130° C. to 350° C. in the presence of a solid body having the following composition which sums to 100 wt %:
silicon dioxide: 61 wt % to 74 wt %;
aluminum oxide: 19 wt % to 23 wt %;
magnesium oxide: 10 wt % to 12 wt %;
sum of other substances: 0 to 10 wt %.

16. The process according to claim 2 , wherein the etherification is affected in the liquid phase at a pressure of 1*10 5 Pa to 7*10 5 Pa and a temperature of 50° C. to 130° C. in the presence

Assignees

• Evonik Degussa Gmbh

Inventors

• Stochniol Guido
• Reeker Helene
• Maschmeyer Dietrich
• Peitz Stephan
• Schallenberg Jörg

Classifications

• C07C2/10

  with metal oxides · CPC title

• C01B33/12 Primary

  Silica; Hydrates thereof, e.g. lepidoic silicic acid · CPC title

• C07C2521/08

  Silica · CPC title

• C07C2/24

  with metals · CPC title

• Y02P20/52

  using catalysts, e.g. selective catalysts · CPC title