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1. WO2020161067 - PROCÉDÉ DE PRÉPARATION DE MÉTHIONINE

Note: Texte fondé sur des processus automatiques de reconnaissance optique de caractères. Seule la version PDF a une valeur juridique

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Patent claims

1 . A process for the preparation of methionine comprising the step of contacting a solution or suspension comprising 2-amino-4-(methylthio)butanenitrile and/or 2-amino-4- (methylthio)butaneamide with water in the presence of a catalyst to give a methionine comprising mixture, wherein the catalyst comprises CeC>2 comprising particles, wherein the CeC>2 comprising particles comprise from 50 to 100 wt.-% of CeC>2, have a BET surface area of from 35 to 65 m2/g measured according to DIN ISO 9277-5 (2003), a mean maximum Feret diameter XFmax, mean of from 10 to 40 nm and a mean minimum Feret diameter XFmin, mean of from 5 to 30 nm, both measured according to DIN ISO 9276-6 (2012).

2. The process according to claim 1 , wherein the catalyst comprises from 25 to 100 wt.-% of the 0eO2, based on the total weight of the catalyst.

3. The process according to any of claims 1 to 2, wherein the 0eO2 comprising particles have a mean minimum Feret diameter XFmin, mean of from 9 to 25 nm.

4. The process according to any of claims 1 to 3, wherein the CeC>2 comprising particles have a mean maximum Feret diameter XFmax, mean of from 13 to 36 nm.

5. The process according to any of claims 1 to 4, wherein the mean minimum Feret diameter XFmin, mean of the CeC>2 comprising particles is always smaller than the mean maximum Feret diameter XFmax, mean of said particles.

6. The process according to any of claims 1 to 5, wherein the CeC>2 comprising particles have a mean aspect ratio XFmin, mean / XFmax, min of from 0.55 to 0.85, measured according to DIN ISO 9276-6 (2012).

7. The process according to any of claims 1 to 6, wherein the 0eO2 comprising particles have a lattice plane distance of from 0.24 to 0.32 nm.

8. The process according to any of claims 1 to 7, wherein the 0eO2 comprising particles comprise octahedral particles.

9. The process according to any of claims 1 to 8, wherein the 0eO2 comprising particles have a mean equivalent circular diameter XA, mean of from 5 to 45 nm, measured according to DIN ISO 9276-6 (2012).

10. The process according to any of claims 1 to 9, wherein the 0eO2 comprising particles have a crystallinity of at least 50 %.

1 1 . The process according to any of claims 1 to 10, wherein the contacting step is performed at a temperature of 90°C at the most with a 2-amino-4-(methylthio)butanenitrile comprising solution or suspension.

12. The process according to any of claims 1 to 1 1 , wherein the methionine comprising mixture obtained from a contacting step is fed to at least one further contacting step.

13. The process according to claim 12, wherein the at least one further contacting step is performed at a temperature ranging from 70 to 140°C.

14. The process according to any of claims 1 to 13, wherein the process further comprises the step of separating the catalyst from the methionine comprising mixture by a continuous cross-flow filtration.

15. The process according to any of claims 1 to 14, wherein the at least one contacting step is accompanied by a vacuum distillation or by stripping of the reaction solution or suspension with water vapor.