Process and reactor for the epoxidation of propene

Patent metadata

Field	Value
Publication number	US-10214504-B2
Application number	US-201615778318-A
Country	US
Kind code	B2
Filing date	Nov 1, 2016
Priority date	Nov 26, 2015
Publication date	Feb 26, 2019
Grant date	Feb 26, 2019

Abstract

Propene is continuously reacted with hydrogen peroxide in a tube bundle reactor comprising a multitude of parallel reaction tubes in the presence of a titanium silicalite catalyst arranged as a fixed bed in the reaction tubes. A cooling jacket encloses the reaction tubes, which has a feed point for cooling medium near the entry of the reaction tubes, a withdrawal point for cooling medium near the end of the reaction tubes and at least one additional withdrawal point upstream of the withdrawal point near the end of the reaction tubes. Cooling medium is fed to the feed point for cooling medium, a part of the cooling medium is withdrawn at the at least one additional withdrawal point and the remainder exits at the withdrawal point near the end of the reaction tubes.

First claim

The invention claimed is:

1. A process for the epoxidation of propene by continuously reacting propene with hydrogen peroxide in the presence of a titanium silicalite catalyst in a tube bundle reactor, wherein:
a) the tube bundle reactor comprises a multitude of parallel reaction tubes and a cooling jacket enclosing the reaction tubes, said cooling jacket having a feed point for cooling medium near the entry of the reaction tubes and a withdrawal point for cooling medium near the end of the reaction tubes;
b) the catalyst is arranged as a fixed bed in the reaction tubes, wherein a mixture comprising propene and hydrogen peroxide is continuously introduced to the entry of the reaction tubes and a reaction mixture comprising propene oxide exits at the end of the reaction tubes;
c) the cooling jacket has at least one additional withdrawal point for cooling medium, upstream of the withdrawal point for cooling medium near the end of the reaction tubes, wherein:
i) cooling medium is fed to the feed point for cooling medium;
ii) a part of the cooling medium fed to said feed point is withdrawn at the at least one additional withdrawal point; and
iii) the remainder of the cooling medium fed to said feed point exits at the withdrawal point near the end of the reaction tubes.

2. The process of claim 1 , wherein the at least one additional withdrawal point is located at from 15 to 70% of the length of the reaction tubes.

3. The process of claim 1 , wherein from 10 to 70% of the cooling medium fed is withdrawn at the at least one additional withdrawal point.

4. The process of claim 2 , wherein from 10 to 70% of the cooling medium fed is withdrawn at the at least one additional withdrawal point.

5. The process of claim 1 , wherein the cooling medium is water circulated in a secondary cooling circuit.

6. The process of claim 1 , wherein baffles are arranged in the cooling jacket transverse to the reaction tubes across part of the cross section of the cooling jacket, guiding cooling medium transverse to the reaction tubes, said baffles having openings near or adjacent to the inner wall of the cooling jacket or a gap between the baffle and the inner wall of the cooling jacket.

7. The process of claim 6 , wherein the at least one additional withdrawal point is located at from 15 to 70% of the length of the reaction tubes.

8. The process of claim 6 , wherein from 10 to 70% of the cooling medium fed is withdrawn at the at least one additional withdrawal point.

9. The process of claim 1 , wherein initially no cooling medium is withdrawn at the additional withdrawal point until conversion of hydrogen peroxide decreases to a target value due to catalyst deactivation, followed by withdrawing an increasing part of the cooling medium at the additional withdrawal point to maintain an essentially constant conversion of hydrogen peroxide.

10. The process of claim 9 , wherein withdrawal of cooling medium at the additional withdrawal point is increased until the fraction of cooling medium withdrawn at the additional withdrawal point reaches a target value, and thereafter the fraction of cooling medium withdrawn at the additional withdrawal point is kept within 0.8 to 1.2 times the target value and the temperature of the cooling medium is increased to maintain an essentially constant conversion of hydrogen peroxide.

11. The process of claim 1 , wherein the parallel reaction tubes are arranged vertically and a mixture comprising propene, hydrogen peroxide and methanol solvent is passed through the reaction tubes in down-flow in trickle mode.

12. The process of claim 11 , wherein the at least one additional withdrawal point is located at from 15 to 70% of the length of the reaction tubes.

13. The process of claim 11 , wherein from 10 to 70% of the cooling medium fed is withdrawn at the at least one additional withdrawal point.

14. The process of claim 11 , wherein baffles are arranged in the cooling jacket transverse to the reaction tubes across part of the cross section of the cooling jacket, guiding cooling medium transverse to the reaction tubes, said baffles having openings near or adjacent to the inner wall of the cooling jacket or a gap between the baffle and the inner wall of the cooling jacket.

15. The process of claim 11 , wherein the mixture comprising propene, hydrogen peroxide and methanol solvent comprises two liquid phases, a first phase rich in propene and a second phase rich in methanol and hydrogen peroxide.

16. The process of claim 1 , wherein propene is reacted with hydrogen peroxide at a temperature of from 20 to 80° C. and a pressure of from 1.9 to 5.0 MPa.

17. A tube bundle reactor for the continuous epoxidation of propene comprising a multitude of parallel reaction tubes and a cooling jacket enclosing the reaction tubes, said cooling jacket having a feed point for cooling medium near the entry of the reaction tubes and a withdrawal point for cooling medium near the end of the reaction tubes, wherein the cooling jacket has at least one additional withdrawal point for cooling medium, upstream of the withdrawal point for cooling medium near the end of the reaction tubes.

18. The tube bundle reactor of claim 17 , wherein the at least one additional withdrawal point is located at from 15 to 70% of the length of the reaction tubes.

19. The tube bundle reactor of claim 17 , wherein baffles are arranged in the cooling jacket transverse to the reaction tubes across part of the cross section of the cooling jacket for guiding cooling medium transverse to the reaction tubes, said baffles having openings near or adjacent to the inner wall of the cooling jacket or a gap between the baffle and the inner wall of the cooling jacket.

20. The tube bundle reactor of claim 19 , wherein the at least one additional withdrawal point is located at from 15 to 70% of the length of the reaction tubes.

Assignees

• Evonik Degussa Gmbh
• Thyssenkrupp Ind Solutions Ag

Inventors

• Brendel Marc
• Bärz Manfred
• Kowoll Johannes
• Bolz David
• Hofen Willi
• Schemel Jürgen
• Jaeger Bernd
• Bredemeyer Niels
• Kolbe Bärbel
• Ullrich Norbert
• Dopfer Michael
• Wöll Wolfgang
• Porscha Peter
• Pfenning Dana
• Bernhard Maik

Classifications

• B01J19/2425 Primary

  in parallel · CPC title

• B01J2219/24

  Stationary reactors without moving elements inside · CPC title

• C07D301/12 Primary

  with hydrogen peroxide or inorganic peroxides or peracids · CPC title

• C07D303/04

  containing only hydrogen and carbon atoms in addition to the ring oxygen atoms · CPC title