# US 10,870,619 B2 · Method for preparing L-methionine crystals using crystallization technique

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- Number: US 10,870,619 B2
- Document ID: US10870619B2
- Status: Granted
- Kind: B2
- Application number: 16/469,852
- Filed: 2017-12-29
- Published: 2019-10-17
- Granted: 2020-12-22
- Earliest claimed: 2016-12-30
- Assignees: Cj Cheiljedang Corporation
- Applicants: Cj Cheiljedang Corporation
- Inventors: Jun-Woo Kim; In Sung Lee; Kee Kahb Koo; Wang Soo Kim; Allan S. Myerson
- Web page: https://patentgrep.com/patent/US10870619B2

## CPC

- B01D 9/0013: {by indirect heat exchange}
- C07C 319/28: Separation; Purification
- B01D 9/0018: {Evaporation of components of the mixture to be separated}
- B01D 9/0054: {Use of anti-solvent}
- B01D 9/0063: {Control or regulation (control per se G05)}
- C07C 319/20: by reactions not involving the formation of sulfide groups
- C07C 323/58: with amino groups bound to the carbon skeleton
- B01D 9/0059: {General arrangements of crystallisation plant, e.g. flow sheets}
- B01D 2009/0086: {Processes or apparatus therefor}
- C07B 2200/13: Crystalline forms, e.g. polymorphs
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07B: GENERAL METHODS OF ORGANIC CHEMISTRY; APPARATUS THEREFOR (preparation of carboxylic acid esters by telomerisation C07C67/47; telomerisation C08F)

## Abstract

The present application relates to a method for preparing L-methionine crystals with an improved bulk density. As the L-methionine crystals prepared according to the method for preparing L-methionine crystals of the present application may have a bulk density of up to 800 g/L, the L-methionine crystals are expected to reduce storage and transport costs of L-methionine powder and improve working conditions due to improved fluidity of the powder.

## Claims

### Claim 1

A method for preparing L-methionine crystals, comprising:
(a) adding a pH control agent to an aqueous solution comprising L-methionine to lower or increase the pH, a step of pH adjustment;
(b) heating the aqueous solution comprising L-methionine, a step of heat treatment;
(b-2) adding a pH control agent to the aqueous solution comprising L-methionine to increase or lower the pH, a step of pH readjustment, between Step (b) and Step (c) or in Step (c); and
(c) extracting L-methionine crystals from the aqueous solution comprising L-methionine, which underwent pH adjustment and heat treatment, a step of extraction of crystals.

### Claim 2 (depends on 1)

The method according to claim 1, further comprising Step (b-1): adding a coagulant to the aqueous solution comprising L-methionine, a step of addition of a coagulant, before Step (b-2).

### Claim 3 (depends on 1)

The method according to claim 1, further comprising Step (b-3): cooling the aqueous solution comprising L-methionine, a step of cooling, before or during Step (c).

### Claim 4 (depends on 1)

The method according to claim 1, wherein when the pH control agent in the step of pH adjustment is a pH-increasing agent, the pH control agent in the step of pH readjustment is a pH-lowering agent, and when the pH control agent in the step of pH adjustment is a pH-lowering agent, the pH control agent in the step of pH readjustment is a pH-increasing agent.

### Claim 5 (depends on 2)

The method according to claim 2, wherein the coagulant is an aromatic compound.

### Claim 6 (depends on 5)

The method according to claim 5, wherein the aromatic compound is at least one compound selected from the group consisting of acetylsalicylic acid, acetaminophen, benzoic acid, salicylic acid, gallic acid, L-tyrosine, and L-phenylalanine.

### Claim 7 (depends on 2)

The method according to claim 2, wherein the coagulant is added in an amount of 2 to 7 parts by weight relative to 100 parts by weight of L-methionine.

### Claim 8 (depends on 1)

The method according to claim 1, wherein the step of heat treatment is to heat to a temperature of 40° C. to 90° C.

### Claim 9 (depends on 3)

The method according to claim 3, wherein the step of cooling is to cool to a temperature of 15° C. to 35° C.

### Claim 10 (depends on 3)

The method according to claim 3, wherein the step of cooling is performed at a rate of 20° C./h or less.

### Claim 11 (depends on 2)

The method according to claim 2, wherein when the pH control agent in the step of pH adjustment is a pH-increasing agent, the pH control agent in the step of pH readjustment is a pH-lowering agent, and when the pH control agent in the step of pH adjustment is a pH-lowering agent, the pH control agent in the step of pH readjustment is a pH-increasing agent.