# US 10,501,409 B2 · Method for producing methionine and/or 2-hydroxy-4-(methylthio) butanoic acid

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- Number: US 10,501,409 B2
- Document ID: US10501409B2
- Status: Granted
- Kind: B2
- Application number: 16/124,764
- Filed: 2018-09-07
- Published: 2019-03-14
- Granted: 2019-12-10
- Earliest claimed: 2017-09-08
- Assignees: Sumitomo Chemical Company, Limited
- Applicants: Sumitomo Chemical Company, Limited
- Inventors: Masayuki Ikeguchi
- Web page: https://patentgrep.com/patent/US10501409B2

## CPC

- C07C 319/20: by reactions not involving the formation of sulfide groups
- B01J 23/10: of rare earths
- B01J 2523/3712: Cerium
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS

## Abstract

An object of the invention is to provide a simple method for producing methionine and/or 2-hydroxy-4-(methylthio)butanoic acid at a high yield using 3-(methylthio)propionaldehyde as a raw material. An oxide catalyst containing cerium, 3-(methylthio)propionaldehyde, a compound containing cyanide ion, ammonia or a compound containing ammonium ion, and water are contacted with each other to produce methionine and/or 2-hydroxy-4-(methylthio)butanoic acid.

## Claims

### Claim 1

A method for producing methionine and 2-hydroxy-4-(methylthio)butanoic acid, comprising contacting
an oxide catalyst containing cerium,
3-(methylthio)propionaldehyde,
a compound containing cyanide ion, ammonia or a compound containing ammonium ion, and
water
with each other,
wherein the amount of the oxide catalyst containing cerium is, in a cerium amount, 0.02 to 1.5 moles, per mole of 3-(methylthio)propionaldehyde.

### Claim 2 (depends on 1)

The method according to claim 1, wherein the oxide catalyst containing cerium is at least one oxide selected from cerium oxides and oxide solid solutions containing cerium.

### Claim 3 (depends on 1)

The method according to claim 1, wherein the compound containing cyanide ion is hydrogen cyanide.

### Claim 4 (depends on 1)

The method according to claim 1, wherein ammonia or the compound containing ammonium ion is at least one member selected from aqueous ammonia, liquid ammonia, and ammonia gas.

### Claim 5 (depends on 1)

The method according to claim 1, wherein the reaction temperature is 40 to 110° C.

### Claim 6 (depends on 1)

The method according to claim 1, wherein the oxide catalyst containing cerium, 3-(methylthio)propionaldehyde, hydrogen cyanide, ammonia, and water are contacted with each other in a single vessel.

### Claim 7 (depends on 1)

The method according to claim 1, wherein the oxide catalyst containing cerium and 3-(methylthio)propionaldehyde are contacted with each other in the presence of the compound containing cyanide ion and ammonia or the compound containing ammonium ion.

### Claim 8 (depends on 1)

The method according to claim 1, wherein, after the oxide catalyst containing cerium, the compound containing cyanide ion, ammonia or the compound containing ammonium ion, and water are mixed, the mixture is mixed with 3-(methylthio)propionaldehyde.