Continuous method for producing Grignard adducts and a device for carrying out same

Patent metadata

Field	Value
Publication number	US-11667653-B2
Application number	US-201716092412-A
Country	US
Kind code	B2
Filing date	Mar 29, 2017
Priority date	Apr 13, 2016
Publication date	Jun 6, 2023
Grant date	Jun 6, 2023

Abstract

The invention relates to a continuous method for the production of Grignard adducts, in which the magnesium chips are activated mechanically in situ. Furthermore, the invention relates to a device for implementation of the method according to the invention.

First claim

The invention claimed is:

1. A continuous method for producing a Grignard adduct, wherein said continuous method is conducted in only one reactor, wherein a flow consisting of an alkyl- or aryl halide and a water-free solvent and a further flow consisting of magnesium chips are fed to the reactor such that the magnesium chips drop downwards and form a packed bed in which the chips abut each other, wherein the magnesium chips are fed such that a molar excess of the magnesium chips is present in the reactor relative to the alkyl-or aryl halide, the average dwell time of reagents in the reactor is 1.0 to 20.0 minutes, and the magnesium chips are activated mechanically in the reactor, without utilizing an agitator, but by friction of the magnesium chips against each other triggered by vibrations such that a passivation layer or passivation layers located on a surface of the magnesium chips is/are removed, said vibrations further causing compaction of the activated magnesium chips, and wherein a degree of conversion of the alkyl- or aryl halide to a Grignard adduct at an output of the reactor is at least 90%, wherein the continuous method does not utilize ultrasound to activate the magnesium chips.

2. The method according to claim 1 , wherein the magnesium chips have an average size of 0.5 to 3.0 mm.

3. The method according to claim 1 , wherein the solvent consists of an ether or a mixture of ethers.

4. The method according to claim 3 , wherein the ether is diethyl ether, 2-methyl-tetrahydrofuran, tetrahydrofuran, or a mixture thereof.

5. The method according to claim 1 , wherein the reactor is temperature-controlled at a temperature of 10 to 60° C.

6. The method according to claim 1 , wherein the alkyl- or aryl halide is fed to the reactor in a concentration of 0.5 mol/l to 5.0 mol/l.

7. The method according to claim 1 , wherein the molar excess is at least 5-times molar excess.

8. The method according to claim 1 , wherein an electrophilic educt is fed in addition to the reactor, wherein said electrophilic educt is selected from the group consisting of aldehydes, ketones, carboxylic acid esters, thioesters, boronic acid esters, nitriles, imines, epoxides, disulphides, carbon dioxide, further alkyl- or aryl halides or other compounds which comprise active hydrogen or polar double bonds, and mixtures thereof.

9. The method according to claim 1 , wherein the average dwell time of reagents in the reactor is 5.0 to 10.0 minutes.

10. The method according to claim 1 , wherein the reactor is temperature-controlled at a temperature of 30 to 40° C.

11. A continuous method for producing a Grignard adduct, wherein said continuous method is conducted in only one reactor, wherein the reactor is temperature- controlled at a temperature of 10° C. to 60° C., wherein a flow consisting of an alkyl- or aryl halide and a water-free solvent and a further flow consisting of magnesium chips are fed to the reactor such that the magnesium chips drop downwards and abut each other to form a packed bed, wherein the magnesium chips are fed such that a molar excess of the magnesium chips is present in the reactor relative to the alkyl- or aryl halide, the average dwell time of reagents in the reactor is 1.0 to 20.0 minutes, and the magnesium chips are activated mechanically in the reactor, without utilizing an agitator, by friction of the magnesium chips against each other triggered by vibrations which create a wobbling motion of the magnesium chips such that a passivation layer or passivation layers located on a surface of the magnesium chips is/are removed and further cause a compaction of the activated magnesium chips, and wherein a degree of conversion of the alkyl- or aryl halide to a Grignard adduct at an output of the reactor is at least 90%, wherein the continuous method does not utilize ultrasound to activate the magnesium chips.

12. The method according to claim 11 , wherein the magnesium chips have an average size of 0.5 to 3.0 mm.

13. The method according to claim 11 , wherein the water-free solvent consists of an ether or a mixture of ethers.

14. The method according to claim 13 , wherein the ether is diethyl ether, 2-methyl-tetrahydrofuran, tetrahydrofuran, or a mixture thereof.

15. The method according to claim 11 , wherein the molar excess is at least 5-times molar excess.

16. The method according to claim 11 , wherein an electrophilic educt is fed in addition to the reactor, wherein said electrophilic educt is selected from the group consisting of aldehydes, ketones, carboxylic acid esters, thioesters, boronic acid esters, nitriles, imines, epoxides, disulphides, carbon dioxide, further alkyl- or aryl halides or other compounds which comprise active hydrogen or polar double bonds, and mixtures thereof.

17. The method according to claim 1 , wherein the vibrations have a frequency of 20 Hz to 200 Hz.

18. The method according to claim 1 , wherein the reactor is made of a metal.

19. The method according to claim 1 , wherein the reactor comprises a device for mechanical activation of the magnesium chips, which device consists of a shaker, a vibration- and/or a grinding device and is fitted on or in the reactor or effectively connected to it for introducing the shaking or vibration movement.

20. The method according to claim 1 , wherein the flow fed to the reactor consists of an aryl halide and a water-free solvent, the magnesium chips are fed such that a molar excess of the magnesium chips is present in the reactor relative to the aryl halide, the average dwell time of reagents in the reactor is 1.0 to 20.0 minutes, and the magnesium chips are activated mechanically in the reactor, without utilizing an agitator, but by friction of the magnesium chips against each other triggered by vibrations such that a passivation layer or passivation layers located on a surface of the magnesium chips is/are removed, said vibrations further causing compaction of the activated magnesium chips, and wherein a degree of conversion of the aryl halide to a Grignard adduct at an output of the reactor is at least 90%.

Assignees

• Fraunhofer Ges Forschung

Inventors

• Menges-Flanagan Gabriele
• Hofmann Christian

Classifications

• B01J19/0053

  Details of the reactor · CPC title

• C07B49/00

  Grignard reactions · CPC title

• C07F3/02 Primary

  Magnesium compounds · CPC title