Process of purifying methionine

Abstract

The present invention provides a process for purifying methionine. A methionine product having a purity of up to 99% or higher is obtained by separating methionine from a salt by-product through a process comprising adsorption and desorption using a macroporous adsorption resin, where the methionine content in the salt by-product is 0.03%. The yield of methionine extracted with the resin is up to 98% or higher. By using the process of the present invention, the existing production process is simplified, the quality of the methionine product is improved, and the production costs for methionine are reduced.

Claims

1. A process for purifying methionine, wherein methionine is separated from a salt by-product by using a macroporous adsorption resin, in which the methionine is adsorbed onto the macroporous adsorption resin, and then the methionine is recovered by desorbing from the resin using a desorbent; and the salt by-product is not absorbed onto the macroporous adsorption resin during the adsorption process, but enters an effluent resulting from the adsorption, the process comprising the following steps: 1) flowing a methionine solution comprising methionine and a salt by-product being at least one of sodium carbonate, sodium sulfate, ammonium sulfate, potassium carbonate, ammonium carbonate, or potassium sulfate, or a mixture of two or more thereof, from the top to the bottom, through a macroporous adsorption resin layer, and stopping resin adsorption when the content of methionine in the effluent from the resin column is 1 to 50% (w/w) of the content at the inlet, in which the effluent resulting from the resin adsorption is a salt by-product; 2) resin desorption: desorbing, from the top to the bottom, the resin that has completed the adsorption in step 1) using a desorbent, and collecting the desorption solution; and 3) subsequent process: subjecting the desorption solution to subsequent treatments following an existing process.

2. The process for purifying methionine according to claim 1, wherein the methionine is selected from methionine and a hydroxyl derivative of methionine.

3. The process for purifying methionine according to claim 1, wherein in the resin adsorption of step 1), the methionine solution to be adsorbed is adjusted to pH 1.0-10.0.

4. The process for purifying methionine according to claim 3, wherein in the resin adsorption of step 1), the methionine solution to be adsorbed is adjusted to pH 1.0-5.0.

5. The process for purifying methionine according to claim 4, wherein in the resin adsorption of step 1), the methionine solution to be adsorbed is adjusted to pH 2.0-3.0.

6. The process for purifying methionine according to claim 1, wherein the methionine solution is flowed through the macroporous adsorption resin layer at a flow rate of 1-10 BV/h.

7. The process for purifying methionine according to claim 6, wherein the methionine solution is flowed through the macroporous adsorption resin layer at a flow rate of 1-5 BV/h.

8. The process for purifying methionine according to claim 7, wherein the methionine solution is flowed through the macroporous adsorption resin layer at a flow rate of 1-3 BV/h.

9. The process for purifying methionine according to claim 1, wherein the desorbent is selected from sodium hydroxide, potassium hydroxide, acetic acid, acetonitrile, sulfuric acid, nitric acid, bromohydric acid, hydrochloric acid, sodium chloride, aqueous ammonia, methanol, ethanol, i-propanol, isobutanol, ethyl acetate, and acetone.

10. The process for purifying methionine according to claim 1, wherein the concentration of the desorbent is 1-50% (w/w) with respect to the desorbent solution.

11. The process for purifying methionine according to claim 10, wherein the concentration of the desorbent is 1-30% (w/w) with respect to the desorbent solution.

12. The process for purifying methionine according to claim 11, wherein the concentration of the desorbent is 2-25% (w/w) with respect to the desorbent solution.

13. The process for purifying methionine according to claim 1, wherein the volume of the desorbent for the resin is 1-10 BV.

14. The process for purifying methionine according to claim 1, wherein the flow rate of the desorbent for the resin is 1-10 BV/h.

15. The process for purifying methionine according to claim 1, wherein in the resin adsorption of step 1), the methionine solution to be adsorbed is adjusted to pH 1.0-3.0; and then the methionine solution is flowed through the macroporous adsorption resin layer at a flow rate of 1-10 BV/h; the desorbent is selected from sodium hydroxide, potassium hydroxide, hydrochloric acid, sodium chloride, aqueous ammonia, methanol, ethanol, i-propanol, and acetone; the concentration of the desorbent is 2-25% (w/w); the volume of the desorbent for the resin is 1-3 BV; and the flow rate of the desorbent for the resin is 1-5 BV/h.

16. The process for purifying methionine according to claim 1, comprising the following steps: 1) resin adsorption: flowing a methionine solution (pH 1.5) with a methionine content of 2.98% (w/w) and an ammonium sulfate content of 41.59% (w/w) evenly, from the top to the bottom, through a 100 ml resin bed of a macroporous adsorption resin trademarked as XDA-1 by Xi'An Sunresin New Materials Co., Ltd at a flow rate of 1 BV/h, collecting the effluent from the resin column separately, and stopping feeding to the resin column when the methionine content in the effluent from the bottom of the resin column is 0.3%; 2) resin desorption: desorbing, from the top to the bottom, the resin using 3 BV of 12% aqueous ammonia solution at a flow rate of 1 BV/h, and collecting the desorption solution; this desorbing solution is collected and sent back to the methionine process with improvement of recycling yield, economical balance, environmental footprint and a simplification of the process; and 3) the resin is regenerated by washing step and prepared for new adsorption with adsorbed solution.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The drawing shows a specific implementation of a process according to the present invention.

DETAILED DESCRIPTION

(2) The present invention is further described by way of examples, in which the methionine solution used is available from two enterprises in Chongqing and Nanjing, respectively.

Example 1

(3) 1. Resin adsorption: A methionine solution (pH 10.72) with a methionine content of 17.24% (w/w) and a sodium carbonate content of 10.35% (w/w) was flowed evenly, from the top to the bottom, through a 100 ml resin bed of a macroporous adsorption resin trademarked as XDA-1 by Xi'An Sunresin New Materials Co., Ltd at a flow rate of 1 BV/h. An effluent from the resin column was collected separately, and feeding to the resin column was stopped when the methionine content in the effluent from the bottom of the resin column is 1.7% (w/w).

(4) 2. Resin desorption: The resin was desorbed from the top to the bottom using 2 BV of a 3% (w/w) sodium hydroxide solution at a flow rate of 1 BV/h, and the desorption solution was collected.

(5) 3.300 ml of the effluent from the resin column was collected, and detected to have a methionine content of 0.02% (w/w), and a sodium carbonate content of 10.35% (w/w). 200 ml of the desorption solution was collected, and detected to have a methionine content of 24.60% (w/w), with a methionine yield of 95.15% (w/w).

Example 2

(6) 1. Resin adsorption: A liquid methionine solution with a methionine content of 2.8% (w/w) and a potassium sulfate content of 17.4% (w/w) was adjusted to pH 2.2 with a 2% (w/w) sulfuric acid solution, and flowed evenly, from the top to the bottom, through a 100 ml resin bed of a macroporous adsorption resin trademarked as XDA-8 by Xi'An Sunresin New Materials Co., Ltd at a flow rate of 1 BV/h. An effluent from the resin column was collected separately, and feeding to the resin column was stopped when the methionine content in the effluent from the bottom of the resin column is 0.3% (w/w).

(7) 2. Resin desorption: The resin was desorbed from the top to the bottom using 3 BV of a 4% (w/w) methanol solution at a flow rate of 1 BV/h, and the desorption solution was collected.

(8) 3. 700 ml of the effluent from the resin column was collected, and detected to have a methionine content of 0.01% (w/w), and a potassium sulfate content of 17.38% (w/w). 302 ml of the desorption solution was collected, and detected to have a methionine content of 6.45% (w/w), with a methionine yield of 98.76% (w/w).

Examples 3-9

(9) The implementation process was specifically the same as that in Example 1, in which the influence of different pH values of the methionine solutions on the adsorption capacity of the resin was mainly investigated, where the concentrations not specifically given in the experiments were all concentrations in percentages by weight.

(10) Methionine content: 2.80% (w/w), ammonium sulfate content: 43.5% (w/w), and potassium carbonate content: 2.1% (w/w). Feed volume: 7 BV, and feed flow rate: 1 BV/h. 5 portions of macroporous adsorption resin trademarked as XDA-8 by Xi'An Sunresin New Materials Co., Ltd were prepared, each portion containing 100 ml resin. The methionine solution was adjusted to pH 1.0, 3.0, 7.0, 9.0, and 10.0 respectively with a 4% (w/w) sodium hydroxide or a 4% (w/w) sulfuric acid solution, and then subjected to an adsorption comparison test.

(11) Adsorption capacity of resin=(Methionine content in the feed*Feed volumeMethionine content in the effluent*Effluent volume)/Resin volume

(12) TABLE-US-00001 Example pH of mother solution Adsorption capacity of resin (g/L) Example 3 1.0 192.1 Example 4 2.0 195.9 Example 5 3.0 194.1 Example 6 5.0 172.5 Example 7 7.0 159.4 Example 8 9.0 102.1 Example 9 10.0 80.2

Examples 10-15

(13) The implementation process was specifically the same as that in Example 1, in which the influence of different adsorption rates on the adsorption capacity of the resin was mainly investigated, where the concentrations not specifically given in the experiments were all concentrations in percentages by weight.

(14) Methionine content: 3.28% (w/w), sodium sulfate content: 40.19% (w/w), pH 2.40. Feed volume: 7 BV. 5 portions of macroporous adsorption resin trademarked as XDA-8 by Xi'An Sunresin New Materials Co., Ltd were prepared, each portion containing 100 ml resin. The resin adsorption was carried out at various flow rates.

(15) TABLE-US-00002 Example Flow rate (BV/h) Adsorption capacity of resin (g/L) Example 10 1 229.6 Example 11 2 225.1 Example 12 3 211.9 Example 13 5 139.2 Example 14 7 91.4 Example 15 10 55.8

Examples 16-24

(16) The implementation process was specifically the same as that in Example 1, in which the desorption rate of various desorbents and the quality of the desorption solution were mainly investigated, where the concentrations not specifically given in the experiments were all concentrations in percentages by weight.

(17) Methionine content: 2.95% (w/w), ammonium sulfate content: 42.04% (w/w), pH 2.20. Feed volume: 7 BV each. The methionine solution was flowed respectively through 7 portions of macroporous adsorption resin (each 100 ml) trademarked as XDA-300 by Xi'An Sunresin New Materials Co., Ltd at a flow rate of 1 BV/h. After adsorption, the resin was desorbed by using 3 BV of 4% (w/w) sodium hydroxide, 4% (w/w) potassium hydroxide, 4% (w/w) hydrochloric acid, 4% (w/w) sodium chloride, 4% (w/w) aqueous ammonia, 4% (v/v) methanol, 4% (v/v) ethanol, 4% (v/v) i-propanol, and 4% (v/v) acetone at a flow rate of 1 BV/h respectively.

(18) TABLE-US-00003 Methionine Ammonium sulfate concentration in the concentration in the desorption solution desorption solution Desorption Example Desorption solution (%) (%) rate (%) Example 4% (w/w) sodium 6.03 0.03 87.6 16 hydroxide Example 4% (w/w) potassium 5.98 0.02 86.9 17 hydroxide Example 4% (w/w) hydrochloric 5.81 0.01 84.4 18 acid Example 4% (w/w) sodium 5.21 0 75.7 19 chloride Example 4% (w/w) aqueous 6.69 0.02 97.3 20 ammonia Example 4% (v/v) methanol 6.79 0.02 98.7 21 Example 4% (v/v) ethanol 6.75 0.05 98.1 22 Example 4% (v/v) i-propanol 6.84 0.02 99.4 23 Example 4% (v/v) acetone 6.84 0.01 99.4 24

Examples 25-29

(19) The implementation process was specifically the same as that in Examples 16-24, in which the influences of different concentrations of a desorbent on the quality of the desorption solution and the desorption rate were mainly investigated.

(20) Methionine content: 2.64% (w/w), ammonium sulfate content: 42.04% (w/w), pH 2.20. Feed volume: 8 BV each. The methionine solution was flowed respectively through 4 portions of macroporous adsorption resin (each 100 ml) trademarked as XDA-8G by by Xi'An Sunresin New Materials Co., Ltd at a flow rate of 1 BV/h. After adsorption, the resin was desorbed by using 3 BV of 1% (w/w) aqueous ammonia, 2% (w/w) aqueous ammonia, 4% (w/w) aqueous ammonia, 8% (w/w) aqueous ammonia, and 10% (w/w) aqueous ammonia at a flow rate of 1 BV/h respectively.

(21) TABLE-US-00004 Methionine concentration in the Desorption Example Desorption solution desorption solution (%) rate (%) Example 1% (w/w) aqueous 6.03 85.59 25 ammonia Example 2% (w/w) aqueous 6.69 95.02 26 ammonia Example 4% (w/w) aqueous 6.97 99.00 27 ammonia Example 8% (w/w) aqueous 6.95 98.73 28 ammonia Example 10% (w/w) aqueous 6.55 93.04 29 ammonia

Examples 30-33

(22) The implementation process was specifically the same as that in Examples 16-24, in which the influences of different volumes of a desorbent on the desorption rate were mainly investigated.

(23) Methionine content: 3.07%, ammonium sulfate content: 44.55%, pH 2.41. Feed volume: 7 BV each. The methionine solution was flowed respectively through 4 portions of macroporous adsorption resin (each 100 ml) trademarked as XDA-200 by Xi'An Sunresin New Materials Co., Ltd at a flow rate of 1 BV/h.

(24) TABLE-US-00005 Volume of Methionine concentration desorption in the desorption solution Desorption rate Example solution (%) (%) Example 30 1 BV 12.47 58.03 Example 31 2 BV 8.75 81.47 Example 32 3 BV 6.99 97.79 Example 33 5 BV 4.21 98.02

Examples 34-37

(25) The implementation process was specifically the same as that in Examples 16-24, in which the influences of different volumes of a desorbent on the desorption rate were mainly investigated.

(26) Methionine content: 2.58% (w/w), ammonium sulfate content: 44.55% (w/w), pH 2.41. Feed volume: 8 BV each. The methionine solution was flowed respectively through 4 portions of macroporous adsorption resin (each 100 ml) trademarked as XDA-300 by Xi'An Sunresin New Materials Co., Ltd at a flow rate of 1 BV/h. After adsorption, the resin was desorbed by using 3 BV of 4% (w/w) acetone solution at a flow rate of 1 BV/h, 3 BV/h, 7 BV/h, and 10 BV/h respectively.

(27) TABLE-US-00006 Flow rate of the Methionine desorption concentration in solution the desorption Example (BV/h) solution (%) Desorption rate (%) Example 34 1 6.79 98.72 Example 35 3 6.78 98.55 Example 36 7 5.55 80.71 Example 37 10 4.84 70.36

Example 38

(28) 1. Resin adsorption: A methionine solution (pH 2.75) with a methionine content of 2.98% (w/w) and an ammonium sulfate content of 41.59% (w/w) was flowed evenly, from the top to the bottom, through a 100 ml resin bed of a macroporous adsorption resin trademarked as XDA-1 by Xi'An Sunresin New Materials Co., Ltd at a flow rate of 1 BV/h. An effluent from the resin column was collected separately, and feeding to the resin column was stopped when the methionine content in the effluent from the bottom of the resin column is 0.3% (w/w).

(29) 2. Resin desorption: The resin was desorbed from the top to the bottom using 3 BV of a 6% (w/w) aqueous ammonia solution at a flow rate of 1 BV/h, and the desorption solution was collected.

(30) 3. 750 ml of the effluent from the resin column was collected, and detected to have a methionine content of 0.01% (w/w), and an ammonium sulfate content of 41.55% (w/w). 300 ml of the desorption solution was collected, and detected to have a methionine content of 6.75% (w/w), with a methionine yield of 98.18% (w/w).