# US 2008/0188696 A1 · Process For Preparing A C4-Olefin Mixture By Selective Hydrogenation And Metathesis Process For Using This Stream

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- Number: US 2008/0188696 A1
- Document ID: US20080188696A1
- Status: Published application
- Kind: A1
- Application number: 11/665,161
- Filed: 2005-10-13
- Published: 2008-08-07
- Earliest claimed: 2004-10-13
- Assignees: BASF SE
- Inventors: Jurgen Stephan; Andreas Brodhagen; Markus Schubert; Frank Poplow; Michael Roper; Thomas Hill
- Web page: https://patentgrep.com/patent/US20080188696A1

## CPC

- C07C 11/08: with four carbon atoms
- C07C 6/04: at a carbon-to-carbon double bond
- C07C 2523/44: Palladium
- Y02P 20/52: using catalysts, e.g. selective catalysts
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

A C4-olefin mixture having a 1,3-butadiene content of from 100 to 500 ppm and a content of 1,2-dienes of less than 10 ppm is described. The present invention further provides a process for preparing this C4-olefin mixture and provides for its use in a metathesis reaction for preparing 2-pentene and/or 3-hexene.

## Claims

### Claim at position 1

1-19. (canceled)

### Claim 20

A C4-olefin mixture comprising a 1,3-butadiene content of from 100 to 500 ppm and a content in cumulated dienes of 1 to 10 ppm, wherein the 1-butene content in the mixture is at least 30% by weight, based on the mixture.

### Claim 21 (depends on 20)

The C4-olefin mixture according to claim 20, wherein the content of cumulated 1,2-dienes is less than 10 ppm.

### Claim 22 (depends on 20)

The C4-olefin mixture according to claim 20, wherein the ratio of 1-butene to 2-butenes in the mixture is from 1.2 to 2.0.

### Claim 23 (depends on 20)

The C4-olefin mixture according to claim 20, wherein the mixture comprises 1-butene, trans-2-butene, cis-2-butene, isobutene, isobutane and n-butane.

### Claim 24

A process for preparing a C4-olefin mixture comprising a 1,3-butadiene content of from 100 to 500 ppm and a content in cumulated dienes of less than 10 ppm,
by hydrogenation of a C4 stream coming from steam crackers,
wherein the hydrogenation in the first hydrogenation stage is carried out over a catalyst which comprises at least one metal of group VIII of the Periodic Table of the Elements as hydrogenation metal and, in addition, a promoter on an oxidic support, with at least 80% of the metal of group VIII of the Periodic Table of the Elements being distributed essentially homogeneously in a layer between the surface of the catalyst and a penetration depth corresponding to not more than 80% of the radius of the catalyst, calculated from the surface of the catalyst, and the promoter being distributed essentially homogeneously over the entire cross section of the catalyst.

### Claim 25 (depends on 24)

The process according to claim 24, wherein the hydrogenation is carried out in at least two hydrogenation stages.

### Claim 26 (depends on 24)

The process according to claim 24, wherein the catalyst has a diameter of from 2.5 to 10 mm, with at least 80% of the metal of group VIII of the Periodic Table of the Elements being distributed essentially homogeneously in a layer between the surface of the catalyst and a penetration depth of not more than 1000 μm, calculated from the surface of the catalyst, and the promoter being distributed essentially homogeneously over the entire cross section.

### Claim 27 (depends on 24)

The process according to claim 24, wherein the oxidic support is a mixture of δ-, θ- and α-aluminum oxide.

### Claim 28 (depends on 24)

The process according to claim 24, wherein the metal of group VIII of the Periodic Table of the Elements is palladium.

### Claim 29 (depends on 24)

The process according to claim 24, wherein the promoter is a metal of group IB of the Periodic Table of the Elements.

### Claim 30 (depends on 29)

The process according to claim 29, wherein the metal of group IB of the Periodic Table of the Elements is silver.

### Claim 31 (depends on 24)

The process according to claim 24, wherein the atomic ratio of the metal of group VIII of the Periodic Table of the Elements to the metal of group IB of the Periodic Table of the Elements is from 0.1 to 10.

### Claim 32 (depends on 25)

The process according to claim 25, wherein the temperature on entry to the second hydrogenation stage is from 20 to 100° C.

### Claim 33 (depends on 25)

The process according to claim 25, wherein the ratio of hydrogen to butadiene is from 1 to 3.

### Claim 34 (depends on 25)

The process according to claim 25, wherein the pressure in the second process stage is from 5 to 50 barg.

### Claim 35 (depends on 20)

A process for preparing an olefin mixture comprising 2-pentene and/or 3-hexene by reaction of the C4-olefin mixture according to claim 20 over a metathesis catalyst.

### Claim 36 (depends on 20, 35)

The process according to claim 35, wherein
a. the C4-olefin mixture according to claim 20 is subjected to a metathesis reaction in the presence of a metathesis catalyst comprising at least one compound of a metal of transition group VI.b, VII.b or VIII of the Periodic Table of the Elements, in which metathesis reaction the butenes present in the C4-olefin mixture are reacted with ethene to give a mixture comprising ethene, propene, butenes, 2-pentene, 3-hexene and butane, with up to 0.6 molar equivalents, based on the butenes, of ethene being able to be used;
b. the starting stream obtained in this way is firstly separated into possibly a low-boiling fraction A comprising C2-C3-olefins and a high-boiling fraction comprising C4-C6-olefins and butanes by distillation;
c. any low-boiling fraction A obtained from (2) is subsequently separated into an ethene-comprising fraction and a propene-comprising fraction by distillation, with the ethene-comprising fraction being recirculated to process step (1) and the propene-comprising fraction being discharged as product;
d. the high-boiling fraction obtained from (2) is subsequently separated into a low-boiling fraction B comprising butenes and butanes, an intermediate-boiling fraction C comprising 2-pentene and a high-boiling fraction D comprising 3-hexene by distillation; and
e. the fractions B and, if appropriate, C being wholly or partly recirculated to process step (1) and the fractions D and, if appropriate, C being discharged as a product.

### Claim 37 (depends on 20, 35)

The process according to claim 35, wherein
(1) the C4-olefin mixture according to claim 20 is subjected to a metathesis reaction in the presence of a metathesis catalyst comprising at least one compound of a metal of transition group VI.b, VII.b or VIII. of the Periodic Table of the Elements, in which metathesis reaction the butenes present in the C4-olefin mixture are reacted with ethene to give a mixture comprising ethene, propene, butenes, 2-pentene, 3-hexene and butane, with up to 0.6 molar equivalents, based on the butenes, of ethene being able to be used;
(2) the starting stream obtained in this way is firstly separated by distillation into a low-boiling C2 fraction which is removed via the top of a distillation column, a low-boiling C3 fraction which is subsequently likewise removed via the top of the distillation column to give a high-boiling fraction comprising C4-C6-olefins and butanes;
(3) the low-boiling C2 fraction obtained in process step (2) is recirculated to process step (1) and the low-boiling C3 fraction is discharged as product;
(4) the high-boiling fraction obtained from (2) is subsequently separated into a low-boiling fraction B comprising butenes and butanes, an intermediate-boiling fraction C comprising 2-pentene and a high-boiling fraction D comprising 3-hexene by distillation; and
(5) the fractions B and, if appropriate, C being wholly or partly recirculated to process step (1) and the fractions D and, if appropriate, C being discharged as a product.