Method for the epoxidation of an olefin with hydrogen peroxide

Patent metadata

Field	Value
Publication number	US-2018030010-A1
Application number	US-201615550814-A
Country	US
Kind code	A1
Filing date	Feb 17, 2016
Priority date	Feb 17, 2015
Publication date	Feb 1, 2018
Grant date	—

Abstract

Epoxidation of an olefin is carried out by continuously reacting the olefin with hydrogen peroxide in the presence of a homogeneous epoxidation catalyst in a reaction mixture comprising an aqueous liquid phase and an organic liquid phase, using a loop reactor with mixing of the liquid phases. The loop reactor comprises a measuring section in which the liquid phases are temporarily separated, at least one pH electrode is arranged in the measuring section in contact with the separated aqueous phase, a pH of the separated aqueous phase is determined with the pH electrode and the pH is maintained in a predetermined range by adding acid or base to the loop reactor.

First claim

1 - 11 . (canceled)

12 . A method for the epoxidation of an olefin, comprising continuously reacting the olefin with hydrogen peroxide in the presence of a homogeneous epoxidation catalyst, wherein:
a) the reaction is carried out in a reaction mixture comprising an aqueous liquid phase and an organic liquid phase using a loop reactor with mixing of the liquid phases, wherein the loop reactor comprises:
i) a measuring section in which the liquid phases are temporarily separated into a separated aqueous phase and a separated organic phase;
ii) at least one pH electrode in said measuring section in contact with the separated aqueous phase;
b) a pH of the separated aqueous phase is determined with said pH electrode and said pH is maintained in a predetermined range by adding acid or base to the loop reactor.

13 . The method of claim 12 , wherein the liquid phases are temporarily separated by lowering the flow rate.

14 . The method of claim 13 , wherein the flow rate is lowered in the measuring section by enlarging the flow cross section.

15 . The method of claim 12 , wherein the measuring section is located in a side stream to the loop reactor.

16 . The method of claim 15 , wherein a valve is used for lowering the flow rate or temporarily stopping the flow in the measuring section.

17 . The method of claim 12 , wherein at least three pH electrodes are arranged side by side in the measuring section.

18 . The method of claim 17 , wherein the pH is determined as the average of the values measured by the pH electrodes, excluding the value that differs most from the other measured values.

19 . The method of claim 12 , wherein the epoxidation catalyst comprises a manganese complex carrying a 1,4,7-trimethyl-1,4,7-triazacyclonane ligand.

20 . The method of claim 19 , wherein the olefin is propene and the pH is maintained in a range of from 3.5 to 4.8.

21 . The method of claim 19 , wherein the olefin is allyl chloride and the pH is maintained in a range of from 2.5 to 4.

22 . The method of claim 12 , wherein the epoxidation catalyst comprises a heteropolytungstate and the pH is maintained in a range of from 1.5 to 4.

23 . A method for the epoxidation of allyl chloride, comprising continuously reacting allyl chloride with hydrogen peroxide in the presence of a homogeneous epoxidation catalyst comprising a manganese complex carrying a 1,4,7-trimethyl-1,4,7-triazacyclonane ligand, wherein:
a) the reaction is carried out in a reaction mixture comprising an aqueous liquid phase and an organic liquid phase using a loop reactor with mixing of the liquid phases, wherein the loop reactor comprises:
i) a measuring section in which the liquid phases are temporarily separated into a separated aqueous phase and a separated organic phase;
ii) at least one pH electrode in said measuring section in contact with the separated aqueous phase;
b) a pH of the separated aqueous phase is determined with said pH electrode and said pH is maintained in a range of from 2.5 to 4 by adding acid or base to the loop reactor.

24 . The method of claim 23 , wherein the measuring section is located in a side stream to the loop reactor.

25 . The method of claim 24 , wherein a valve is used for lowering the flow rate or temporarily stopping the flow in the measuring section.

26 . The method of claim 24 , wherein at least three pH electrodes are arranged side by side in the measuring section.

27 . The method of claim 26 , wherein the pH is determined as the average of the values measured by the pH electrodes, excluding the value that differs most from the other measured values.

Assignees

• Evonik Degussa Gmbh

Inventors

• Breitenbach Uwe
• Imm Sebastian
• Rausch Hans-Martin
• Pascaly Matthias
• Stock Jürgen

Classifications

• B01J2219/00245

  Avoiding undesirable reactions or side-effects · CPC title

• B01J19/2465

  externally, i.e. the mixture leaving the vessel and subsequently re-entering it · CPC title

• B01J2231/72

  Epoxidation · CPC title

• B01J31/1815

  with more than one complexing nitrogen atom, e.g. bipyridyl, 2-aminopyridine · CPC title

• B01J14/00

  Chemical processes in general for reacting liquids with liquids; Apparatus specially adapted therefor (B01J8/00, B01J19/08 take precedence) · CPC title