Process for producing methionine

A technology for producing methionine and methionine, applied in the field of methionine production, can solve the problems of high equipment cost and poor filterability, and achieve the effects of cost-effectiveness, improved filterability and effective recovery

Inactive Publication Date: 2009-12-16
SUMITOMO CHEM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0007] However, according to the conventional method as described above, when the mother liquor after separating the second crystal is concentrated and crystallized, there is a problem of poor filterability for separating the third crystal, which leads to high equipment cost

Method used

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  • Process for producing methionine
  • Process for producing methionine
  • Process for producing methionine

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0059] [Reaction step (1)]

[0060] When a solution of 100 parts / hour 18.7% 5-[2-(methylthio)ethyl]imidazolidine-2,4-dione in water, 1.0 parts / hour potassium hydroxide, 67.6 parts / hour pre-prepared The first concentrated solution of the first crystal mother liquor (containing 6.0% methionine and 13.5% potassium), 25.8 parts / hour pre-prepared solution containing the second crystal (containing 7.6% methionine and 18.2% potassium, and the When the wet filter cake is dissolved in the concentrate of the first crystal mother liquor and the solution is concentrated) is added to the reactor, the hydrolysis reaction is carried out at 173-178° C. under a gauge pressure of 0.88 MPa for a residence time of 1 hour.

[0061] [First crystallization step (2)]

[0062] The reaction solution (133.1 parts / hour) obtained by the above-mentioned hydrolysis reaction, 60.7 parts / hour water and 0.023 parts / hour polyvinyl alcohol were mixed, it was added in the crystallizer, and it was placed under th...

reference example 1

[0076] The first concentrate (18.5 parts / hour) of the first crystal mother liquor obtained in Example 1 was concentrated under pressure at 135° C. under a gauge pressure of 0.2 MPa to obtain 12.3 parts / hour second concentrate (the second Second concentration rate: 1.5 times, the total concentration rate of the first and second concentration: 2.6 times). The second concentrate (12.3 parts / hour) and 3.3 parts / hour isopropanol were mixed and added to the crystallizer, and subjected to carbon dioxide pressurized crystallization at 12-16° C. under a gauge pressure of 0.3 MPa. The resulting slurry was subjected to pressure filtration under a filter gauge pressure of 0.3 MPa. At this time, the specific filtration resistance of the wet cake was 0.55×10 as measured according to the following procedure 10 m / kg.

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Abstract

The present invention provides a process for producing methionine which is advantageous from the viewpoints of cost and wastewater disposal, and which comprises the following steps (1) to (5): (1) a reaction step comprising hydrolysis of 5-[2-(methylthio)ethyl]imidazolidine-2,4-dione in the presence of a basic potassium compound; (2) a first crystallization step comprising introduction of carbon dioxide into the reaction solution obtained in step (1) to precipitate methionine, and separation of the resultant slurry into a precipitate and a mother liquor; (3) a second crystallization step comprising concentration of the mother liquor obtained in step (2), mixing with a lower alcohol, introduction of carbon dioxide into the mixture to precipitate methionine and potassium hydrogen carbonate, and separation of the resultant slurry into a precipitate and a mother liquor; (4) a heating step comprising concentration of the mother liquor obtained in step (3) followed by a heating treatment at 150 to 200 DEG C; and (5) a third crystallization step comprising introduction of carbon dioxide into the heated mother liquor obtained in step (4) to precipitate methionine and potassium hydrogen carbonate, and separation of the resultant slurry into a precipitate and a mother liquor.

Description

technical field [0001] The present invention relates to a method for producing methionine by hydrolysis reaction of 5-[2-(methylthio)ethyl]imidazolidine-2,4-dione [see reaction scheme (1) shown below]. [0002] Reaction scheme (1) [0003] Background technique [0004] Methionine can be used as an animal feed additive. [0005] As an example of a known method for producing methionine, there is a method involving the hydrolysis of 5-[2-(methylthio)ethyl]imidazolidine- 2,4-Diketones. According to this method, methionine can be isolated and obtained in crystal form by inducing crystallization by introducing carbon dioxide into the reaction solution after hydrolysis. However, the mother liquor after separation of methionine still contains methionine in an amount corresponding to its solubility and also potassium bicarbonate, which can be recycled as basic potassium compound. Therefore, the mother liquor can be recycled in the above hydrolysis reaction. However, since imp...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C323/58C07C319/20C07C319/28
CPCC07C319/28C07C319/20C07C323/58
Inventor 古泉善行后藤晃权畔见拓志
Owner SUMITOMO CHEM CO LTD
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