Granted Patent B2

US 12,187,669 · App. 17/413,540 · Granted Jan 7, 2025

Inventors: Daniel Sudhoff (Bergkamen, DE); Judith Hierold (Hanau, DE); Philipp Roth (Hanau, DE); Imad Moussallem (Hanau, DE); Ulf Bindernagel (Cologne, DE); Christian Renner (Gründau, DE)

Assignee: Evonik Operations GmbH

C07C319/20C07D233/76

Abstract

Claims (16)

1. A method for producing 2-hydroxy-4-(methylthio) butyronitrile (MMP-CN), comprising:

a) preparing a crude HCN process gas mixture by Andrussow HCN synthesis from methane, ammonia and oxygen;

b) preparing an HCN process gas mixture by adjusting the amount of ammonia in the crude HCN process gas mixture to between 20% (v/v) and 60% (v/v) of the amount present before adjustment; and

c) contacting the HCN process gas mixture with 3-methyl-mercaptopropionaldehyde (MMP).

2. The method of claim 1 , wherein the ammonia adjustment is performed using an ammonia scrubber equipped with a bypass stream.

3. The method of claim 1 , wherein the ammonia adjustment is performed using an ammonia scrubber enabling a partial ammonia breakthrough.

4. The method of claim 1 , wherein the ammonia is adjusted in step b) to about 40% (v/v) of the ammonia in the crude HCN process gas mixture.

5. The method of claim 4 , wherein adjustment is made using an ammonia scrubber.

6. A method for producing methionine, salts of methionine or derivatives of methionine from HCN, the method comprising:

a) preparing a crude HCN process gas mixture by Andrussow HCN synthesis from methane, ammonia and oxygen;

b) preparing an HCN process gas mixture by adjusting the amount of ammonia in the crude HCN process gas mixture to between 20% (v/v) and 60% (v/v) of the amount present before adjustment; and

c) contacting the HCN process gas mixture with 3-methyl-mercaptopropionaldehyde (MMP) to produce 2-hydroxy-4-(methylthio)-butyronitrile (MMP-CN), or a crude product mixture comprising MMP-CN; and

d) further reacting the MMP-CN or crude product mixture comprising MMP-CN of step c) to produce said methionine, salts of methionine or derivatives of methionine.

7. The method of claim 6 , wherein step d) comprises reacting the 2-hydroxy-4-(methylthio) butyronitrile (MMP-CN) or the crude product mixture comprising MMP-CN, with ammonia and/or ammonium salts and carbon dioxide and/or carbonic acid salts to give 5-(2-methylmercaptoethyl) hydantoin.

8. The method of claim 7 , wherein step d) further comprises reacting the 5-(2-methylmercapto-ethyl) hydantoin under basic conditions with formation of carbon dioxide and ammonia to give at least one methionine salt.

9. The method of claim 8 , wherein step d) further comprises reacting reacting the methionine salt with an acid to give methionine.

Assignments (1)

Priority Claims (1)

Continuity (1)

References Cited (23)