| 13.1% |
With water; potassium hydroxide; at 177℃; under 6600.66 Torr; for 0.6h; |
Into a non-stirred continuous first reaction tank, 5.4 parts per hour of a mixture of a solution containing 5-[2-(methylthio)ethyl]imidazolidine-2,4-dione and a potassium hydroxide aqueous solution was continuously charged. While carbon dioxide and ammonia produced as by-products were continuously distilled off together with water, the reaction solution was continuously charged into a second non-stirred continuous reaction tank which was different from the first reaction tank. At this point, the temperature of the reaction tanks was 177 C. and the gauge pressure was 0.88 MPa. The residence time in the first reactor was 30 minutes, and the residence time in the second reaction tank was 6 minutes, totaling 36 minutes. After reaction, the hydrolyzed solution thus obtained contained 10.4% of potassium, 13.1% of methionine, and 1.29% of methionine dipeptide, and the proportion of methionine dipeptide to methionine was 9.9%. |
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With potassium hydroxide; In water; at 173 - 178℃; under 6600.66 Torr; for 1h; |
[Reaction Step (1)]A hydrolysis reaction was carried out at a temperature of 173 to 178 C. under a pressure of 0.88 MPa (gauge pressure) for a residence time of 1 hour by introducing, into a reaction vessel, 100 parts/hr of an aqueous solution containing 18.7% of 5-[(2-(methylthio)ethyl)]-2,4-imidazolinedione, 1.0 part/hr of potassium hydroxide, 67.6 parts/hr of the primarily concentrated liquid of the first crystal mother liquid described below, and 25.8 parts/hr of the solution of second crystal described below. [First Crystallization Step (2)]The reaction solution (133.1 parts/hr) obtained by the previous hydrolysis reaction was mixed with 60.7 parts/hr of water and 0.023 parts/hr of polyvinyl alcohol and introduced into a crystallization apparatus. Then, the crystallization was carried out at 20 C. under a pressure of 0.3 MPa (gauge pressure) of carbon dioxide gas to precipitate methionine. The resulting slurry was filtered, and the filtration residue was washed with water and then dried at 85 to 105 C. under a slightly reduced pressure to obtain 15.6 parts/hr of methionine (purity: 99.6%; yield: 97%). As a filtrate, 184.0 parts/hr of a first crystal mother liquid was recovered. The first crystal mother liquid obtained in the above (184.0 parts/hr) was introduced into a concentration apparatus and concentrated at 115 C. and then 140 C. under a pressure of 0.2 MPa (gauge pressure) to obtain 106.4 parts/hr of a primarily concentrated liquid (the primary concentration ratio: 1.7 times). The analysis of the primarily concentrated liquid revealed that the methionine concentration was 6.0% and the potassium concentration was 13.5%. As described above, 67.6 parts/hr of the primarily concentrated liquid (106.4 parts/hr) of the above-mentioned first crystal mother liquid was recycled to the hydrolysis reaction. Also, 18.5 parts/hr of the solution was introduced into a heating apparatus and heated at 165 C. under a pressure of 1 MPa (gauge pressure) for a residence time of 1 hour and then introduced into a concentration apparatus and concentrated at 135 C. under a pressure of 0.2 MPa (gauge pressure) to obtain 12.3 parts/hr of a secondarily concentrated liquid (secondary concentration ratio: 1.5 times; cumulative ratio of the primary and secondary concentrations: 2.6 times). Further, 20.3 parts/hr of the remaining was used for dissolution of a wet cake of the second crystal as described below. [Secondary Crystallization Step (3)]The secondarily concentrated liquid of the above-mentioned first crystal mother liquid (12.3 parts/hr) was mixed with 3.3 parts/hr of isopropanol and introduced into the crystallization apparatus. Then, the crystallization was carried out at 12 to 16 C. under a pressure of 0.3 MPa (gauge pressure) of carbon dioxide gas. The resulting slurry was filtered to obtain 7.8 parts/hr of a wet cake of the second crystal as a filtration residue. Also, as a filtrate, 9.1 parts/hr of the second crystal mother liquid was recovered. The wet cake of the second crystal (7.8 parts/hr) from the previous stepwas dissolved in the remainder (20.3 parts/hr) of the above-mentioned primarily concentrated liquid of the first crystal mother liquid, and the solution was introduced into a concentration apparatus and concentrated at 80 C. under atmospheric pressure to remove isopropanol contained in the second crystal to obtain 25.8 parts/ hour of a second crystal solution. The analysis of the second crystal solution revealed that the methionine concentration was 7.6% and the potassium concentration was 18.2%. The second crystal solution (25.8 parts/hr) was recycled to the hydrolysis reaction as described above. [Tertiary Crystallization Step (4)]The second crystal mother liquid (9.1 parts/hr) from the previous step was introduced into a concentration apparatus and concentrated at 80 to 110 C. under atmospheric pressure to distill isopropanol off to obtain 6.0 parts of a primarily concentrated liquid (primary concentration ratio: 1.5 times). The analysis of the primarily concentrated liquid revealed that the methionine concentration was 3.14%, the concentrations of two diastereomers of methionine dipeptides (hereinafter, referred to as MDP-1 and MDP-2, respectively) were 1.55% for MDP-1 and 1.68% for MDP-2, and the potassium concentration was 7.25%. A portion of the primarily concentrated liquid of the second crystal mother liquid was taken and introduced into a concentration apparatus and concentrated at 60 C. under a reduced pressure of absolute pressure of 60 mmHg (8 kPa) until the secondary concentration ratio reached 2.3 times (cumulative ratio of the primary and the secondary concentration: 3.5 times). The analysis of the secondarily concentrated liquid revealed that the glycine concentration was 0.69% and the alanine concentration was 1.07%. The secondarily concentrated liquid of the second crystal mother liquid was introduced into a crystallization apparatus and crystallized at 10 C. under a pressure of 0.3 M... |
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With water; potassium hydroxide; at 173 - 178℃; under 6600.66 Torr; for 1h; |
A hydrolysis reaction was carried out at a temperature of from 173 to 178 C. for a residence time of one hour under a gauge pressure of 0.88 MPa, while introducing, into a reactor, an aqueous solution containing 5-[2-(methylthio)ethyl]imidazolidine-2,4-dione at a concentration of 18.7% (100 parts per hour), potassium hydroxide (1.0 part per hour), a primary concentrated solution (methionine concentration: 6.0%, and potassium concentration: 13.5%) of a first crystallization mother liquor separately prepared (67.6 parts per hour), and a solution containing second crystals separately prepared (methionine concentration: 7.6%, and potassium concentration: 18.2%, i.e., a concentrated solution of a second crystallization wet cake dissolved in the concentrated first crystallization mother liquor) (25.8 parts per hour). |
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Example 1To a reaction tower was continuously supplied a liquid (the whole quantity is 100 parts by weight) containing 7.7 parts by weight of 5-[2-(methylthio)ethyl]imidazolidine-2,4-dione, 8.0 parts by weight of potassium (in terms of simple substance), 3.0 parts by weight of methionine, 0.9 part by weight of methionine dipeptide, and 0.14 part by weight of alanine so that the retention time became 15 minutes. Hydrolysis was performed without stirring while degasification was performed at a constant rate, and a liquid was continuously extracted. The hydrolysis was performed at a gauge pressure of 0.93 MPa and 180.00 C. The degasification was performed so that the extracted liquid amount became 75% of the liquid amount before hydrolysis. By introducing carbon dioxide into a reaction liquid continuously extracted from the hydrolysis tank at a gauge pressure of 0.35. MPa and 20 C., methionine was precipitated, and the resulting slurry was separated into a precipitate and a mother liquid. The resulting mother liquid was concentrated 1.7-fold by heating (135 C.), the resulting concentrated liquid was heated to 180.00 C. with a horizontal-type multitubular heater, and continuously supplied to a drum so that the retention time became 1.2 hours, to heat-degrade methionine dipeptide at a gauge pressure of 1.40 MPa without stirring. When the reaction liquid continuously extracted from the heat degradation tank was concentrated 1.4-fold by heating (135 C.), the alanine content in the resulting concentrated liquid was 0.74 wt %. When carbon dioxide was introduced into the mother liquid at a gauge pressure of 0.30 MPa and 12 C., thereby, methionine and potassium bicarbonate were precipitated, and the resulting slurry was separated into a precipitate and a mother liquid, the methionine recovery rate was 51%. The reaction flow is shown in FIG. 1. |
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Example 2 (0140) 860 g of aqueous ammonium carbonate solution containing 7.8% ammonia and 12.4% carbon dioxide are introduced into a closed reactor. After heating to 90 C. with vigorous stirring, 105 g of the MMP produced in Example 1 and 28.5 g of hydrogen cyanide are gradually injected. The mixture is then maintained at 110 C. for 1 hour. The reactor is cooled to 80 C. and then degassed slowly so as to bring the mixture containing the 5-(2-methylmercaptoethyl)hydantoin to atmospheric pressure. 900 g of 40% potassium hydrogen carbonate solution are added and the mixture is maintained at 180 C. under 8 bar for 20 minutes. The mixture is then gradually depressurized to atmospheric pressure and part of the water is evaporated off so that the mixture contains about 20% potassium methioninate. It is then cooled to about 25 C. and carbon dioxide is injected at a pressure of 2-3 bar so as to lower the pH to 5.6. A suspension is obtained, which is filtered off. The recovered solid is washed and then dried. 98 g of D,L-methionine are recovered. The filtrate is recovered and concentrated, and may be recycled into the solution containing the 5-(2-methylmercaptoethyl)hydantoin. |
| 49 g |
With water; potassium carbonate; at 180℃; under 7500.75 Torr; for 0.833333h; |
Reference Example 1 8 parts by weight of potassium carbonate was added to 100 parts by weight of aqueous solution comprising 19% by weight of 5-[2-(methylthio) ethyl]imidazolidine-2,4-dione, then hydrolysis reaction was carried out at a temperature of 180C under a pressure of 1.0 MPa for 50 minutes to obtain a hydrolysis reaction liquid. To this liquid, carbon dioxide was absorbed at a temperature of 15C under a pressure of 0.45 MPa for 2 hours to obtain a methionine slurry. 600 g of the obtained methionine slurry was poured into a centrifugal filter rotating 1700 per minute at a pouring speed of 600 g per minute to stick crude methionine on the filter fabric. Then, the rotating speed was set to 3800 per minute and water was thrown off for 2 minutes. At this stage, crude methionine was taken out and the content of pure methionine in crude methionine was determined as 49.0 g (conversion based on HPLC measurement). |
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liquid delivery pump was used to deliver the prepared 5-(beta-methylthioethyl)glycolyurea solution to the second tubular reactor R3 at the velocity of 1062 Kg/h. A reaction fluid stayed in the second tubular reactor for 9 minutes at the temperature of 190 C. for saponification prior to decompression in the T3 absorption column. Ammonia gas and carbon dioxide produced during reaction were discharged to the CO2 and NH3 absorption column T2 for absorption. The saponification liquid was cooled down to the temperature of 30 C. in the heat exchanger, which was further delivered to the continuous extraction column T4 via the pump at the velocity of 1056 Kg/h. Meanwhile, 1200 Kg/h ethylene glycol dipropyl ether was delivered to the continuous extraction column T4 for continuous reversed extraction. Continuous differential distillation of the ethylene glycol dipropyl ether layer was conducted in the organic solvent recycling distillation column T5 to recycle the solvent for circulated use during extraction process, and incinerate tailings at the same time. A water layer was delivered to continuous crystallizer T6 at the velocity of 1050 Kg/h, and simultaneously CO2 gas was delivered to continuous crystallizer T6 for acidification until PH value of the reaction system was up to 9. Continuous crystallization was conducted at the temperature of 30 C., and the reaction fluid stayed in continuous crystallizer for 3 hours. The crystallization liquid was subject to continuous centrifugal solid-liquid separation in the first solid-liquid separator S1 to filtrate crude D,L-methionine product, and the crystallization mother solution was prepared for further use. A solid delivery equipment was used to deliver crude D, L-methionine product to the scrubber R4 for spiral agitation and washing in the specified quantity at the velocity of 35 Kg/h. Meanwhile, 60 Kg/h water was continuously delivered to the scrubber R4 to control temperature of materials in the scrubber R4 below 30 C. The solid material stayed in the scrubber R4 for 10 minutes. The intermixture subjected to continuous agitation and washing in the scrubber R4 was under continuous centrifugal solid-liquid separation via the second solid-liquid separator S2. A washing filtrate was poured into the crystallization mother solution, and the filter cake of D,L-methionine as filtered was airflow dried at the temperature of 130 C. under the protection of N2 to obtain 27.8 Kg/h finished D, L-methionine product. Inspection according to GB-T17810-2009 Feed Grade DL-Methionine was conducted to obtain the result that methionine content was up to 99.3%, and total molar reaction yield as based on 3-methylthio propionaldehyde was up to 93.3%. (0059) The crystallization mother solution and washing filtrate were delivered to the KHCO3 decomposition column T7 at the velocity of 1106 Kg/h, and they stayed for 3 hours at the temperature of 120 C. to decompose potassium hydrogen carbonate contained in the mother solution into potassium carbonate. Meanwhile, 245 Kg/h water and 7 Kg/h 2-ethylhexyl alcohol were prepared through distillation at the column top. The distilled water was circulated to the scrubber R4 at 60 Kg/h for agitation prior to further use; whereas remaining 185 Kg/h distilled water was used in the CO2 and NH3 absorption column T2. Distilled 2-ethylhexyl alcohol was circulated to the extraction column T4 for further use; whereas CO2 gas discharged through decomposition was used for acidification and crystallization in continuous crystallizer T6 after compression. The potassium carbonate solution containing mother solution discharged from the column bottom was cooled prior to circulation to the HCN absorption column T1 for absorption of formonitrile. |
| 178.26 g |
With water; potassium carbonate; at 180℃; under 760.051 Torr; for 0.333333h;Large scale; |
3484.4 g of an aqueous solution of 5- (2-methylthioethyl) -hydantoin was added to a high pressure reactor, wherein 5- (2-methylThioethyl) -hydantoin 696.88 g (4 mil), followed by the addition of 1658.4 g of aqueous potassium carbonate solution having a mass fraction of 50%Sealed high pressure reactor,Immediately heated to 180 C, the insulation reaction for 20 minutes, and then pressure to atmospheric pressure, the resulting saponification solution after stripping, the saponification of ammonia in the residual less than 50ppm; to the saponification of ammonia after the introduction of carbon dioxide, The temperature of the carbon dioxide is 0.5MPa, the neutralization temperature is 20 C, the neutralization end point is 6.8, the filtrate is filtered and the water is washed with a small amount to obtain the methionine wet product and dried to obtain 415.9 g of methionine product Water was added to the filtered mother liquor to obtain 3659.44 g of aqueous solution of potassium bicarbonate containing methionine (5% by mass of methionine, 32.7% by mass of potassium bicarbonate, potassium carbonate, potassium formate, potassium acetate and the like) About 1% of the total mass), the mother liquor is a uniform light yellow transparent liquid.The aqueous solution of methionine-containing potassium bicarbonate obtained as described above was incubated at 20 C with 100 ml of a fillerChromatographic resin column separation, water consumption 3000ml, column temperature 20 , respectively, D, L-methionine solution and bicarbonateThe recovery rate of D, L-methionine was 97%, which was potassium carbonate, potassium formate, potassium acetate,Desalination rate of 98% or more.Chromatographic separation: feed flow rate 12-18ml / min, into the eluent flow rate 20-30ml / min, the material flow rate14-20 ml / min, eluent flow rate 18-28 ml / min.The D, L-methionine clear solution was concentrated to a concentration, and then crystallized by cooling, suction and drying to obtain D, L-methionineProduct 178.26 grams, the purity of 99.4%; potassium bicarbonate solution by heating to 110 C, to be potassium carbonate water soluble, can be recycled to 5- (2-methylthioethyl) - hydantoin hydrolysis with alkali |
| 178.26 g |
With potassium carbonate; In water; at 180℃; under 760.051 Torr; for 0.333333h;Autoclave; Large scale; |
3484.4 g of an aqueous solution of 5- (2-methylthioethyl) -hydantoin was added to a high pressure reactor, wherein 5- (2-methylThioethyl) -hydantoin 696.88 g (4 mol) was added followed by 1658.4 g of aqueous potassium carbonate solution having a mass fraction of 50%Close the autoclave, immediately heated to 180 , incubation reaction for 20 minutes, and then pressure to atmospheric pressure, the saponification solutionAfter stripping, the residual ammonia in the saponification solution is less than 50 ppm; carbon dioxide is introduced into the saponification solution after deamination, and carbon dioxideThe pressure is 0.5MPa, the neutralization temperature is 20 , the neutralization end point is 6.8, the crystals are sucked and washed with a small amount to obtain methionineWet product, after drying, to get the content of 99.3% methionine products 415.9 grams; washing water and filter the mother liquor to get containing egg ammoniaAcid potassium bicarbonate aqueous solution 3659.44 grams (methionine mass content of 5%, potassium bicarbonate mass percentage content of32.7%, potassium carbonate, potassium formate, potassium acetate and so on accounted for about 1% of the total mass of the mother liquor), the mother liquor for the same light yellowLiquid.The aqueous solution of potassium bicarbonate containing methionine obtained above was passed through a precision filter and kept at a temperature of 25 CUnder the phase into the membrane of the same phase membrane electrodialysis desalination treatment, the same phase membrane electrodialysis has three rooms, namely the liquid chamber, liquid chamber (lightRoom) and the receiving chamber (compounding chamber), during the desalination process, due to the migration of potassium bicarbonate to the concentrate chamber, the feed liquid is fed to the carbon dioxide to maintain the pHIn about 7.0. When the potassium bicarbonate in the liquid chamber is reduced to 5%, the material in the liquid chamber is transferred to the heterogeneous membrane electrodialysisSystem for deep desalination, after two electrodialysis desalination, liquid potassium bicarbonate content of less than 0.05%, methionine content of4.5%; after two electrodialysis desalination, methionine retention rate reached 98.8%, desalination rate reached 99.5%.The D, L-methionine clear solution was concentrated to a concentration, and then crystallized by cooling, suction and drying to obtain D, L-methionineProduct 178.26 g, purity 99.4%; the above-obtained potassium bicarbonate solution was heated to 120 C to obtain potassium carbonate waterSoluble, can be recycled to 5- (2-methylthioethyl) -hydantoin hydrolysis with alkali. |
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