CAS number：63-68-3
molecular formula：C5H11NO2S
molecular weight：149.21
EINECS number：200-562-9

English synonyms

L-Met-OH;L-Methionine, Animal-Free;L-METHIONINE (13C5,D8,15N);L-METHIONINE (1,2,3,4-13C4;METHYL-13CH3);L-METHIONINE, REAGENT GRADE, >=98% (;L-MethionineUSP, 98.5-101.5% (Titration: anhydrous basis);L(-)-Methionin

Related categories

Stable isotope-labeled amino acids; isotope labels; protected amino acids; unnatural amino acids; amino acids and derivatives; intermediates; organic chemical raw materials; nutritional enhancers-amino acids; amino acids; biochemicals; neutral amino acids; amino acids; food additives ;Nutrition enhancer (nutritional supplement; amino acid derivatives; chemical reagents; nutritional enhancers; organic chemical industry; biochemical reagents-amino acids; reagents; food additives; amino acids; chemical raw materials-1; organic raw materials; amino acids and their derivatives ; Chinese medicine reference substance; standard substance; chemical biology; plant extracts; other heterocycles; reference substance; fine chemicals; other biochemical reagents; pharmaceutical intermediates; nutritional supplements; food and feed additives; biochemical reagents; medical raw materials; food Addition; reference substance-traditional Chinese medicine reference substance; raw materials; agricultural and veterinary raw materials; standard substance-traditional medicine standard substance; biochemical reagent-amino acid; medicine, pesticide and dye intermediate; additive; organic chemical raw material; chemical raw material; pharmaceutical raw material; bulk ;Nutrition Enhancer;Commodity Chemicals;General Biochemical Reagents-Amino Acids;APIs;Chemical Reagents;Chemical Intermediates;Amino Acids;Amino Acid Derivatives;Methionine [Met, M];Amino Acids and Derivatives;Amino Acids;Chiral Compound ;Miscellaneous Compounds;Amino Acids & Derivatives;Sulfur & Selenium Compounds;amino;fertilizer;Clinical Test Reference Material;bc0001

Introduction

Methionine is a sulfur-containing non-polar aliphatic amino acid, also known as methionine, which is one of the essential amino acids for human body, abbreviated as Met and M. Glycogenic essential amino acids. It was isolated from casein in 1922. It is the only amino acid containing a thioether structure. There are l-body and dl-body. Natural products are l-body. The relative molecular mass is 149.21. Has a special smell. Slightly sweet. Stable to air and heat. L-methionine can be hydrolyzed or produced by fermentation from many proteins. DL-methionine is chemically synthesized by the following reaction,

It is white flaky crystal or crystalline powder, very smelly and slightly sweet. mp280-282°C (decomposition), no optical activity, stable to heat and air, unstable to strong acid, can lead to demethylation. Soluble in water (3.5%, 25℃), dilute acid and dilute alkali solution, very difficult to dissolve in ethanol, insoluble in ether. The isoelectric point is 5.74.

●  Amino acid drugs, nutritional supplements. For liver cirrhosis and fatty liver. In addition, it is widely used as a feed additive to improve the quality of feed, increase the utilization rate of natural protein and promote the development of animals. For example, DL-methionine can increase the egg production of chickens, increase the weight of pigs, and increase the milk production of dairy cows. Adverse reactions: Contraindicated in hepatic coma.

●  nutritional supplements. One of the essential amino acids for the human body. Because the price is higher than DL-methionine and the effect is equal, DL-methionine is commonly used.

●  nutritional supplements. One of the essential amino acids for the human body.

●  Used in biochemical research and nutritional supplements, also used in adjuvant treatment of pneumonia, liver cirrhosis and fatty liver

●  It is obtained by splitting the optical rotation of acetyl-DL-methionine through amylase.

●  crafting process
Dehydration Feed according to glycerin, potassium bisulfate, and potassium sulfate at a ratio of 1:0.5:0.026. Put 1/7 of the amount of glycerin and all the potassium bisulfate and potassium sulfate into the reaction tank. After the temperature rises to 190°C, start to add the rest of glycerin dropwise. Control the reaction temperature at 180-220°C. Aldehyde gas is collected in a storage tank through a condenser to obtain crude acrolein. Add 10% NaHCO3 solution to the crude product to adjust the pH to 6, carry out fractional distillation, and collect fractions at 50-75°C to obtain crude acrolein. Addition Feed according to the ratio of acrolein, methylisothiourea sulfate, sodium hydroxide, copper acetate, formic acid in a ratio of 1:2.45:3.8:0.01:0.024.
For cyclization, first put methylisothiourea sulfate into the methyl mercaptan generating tank, add NaOH solution dropwise, and heat at the same time to control the temperature not to exceed 95°C. The generated methyl mercaptan first enters the buffer tank, and then enters the 50% The washing tank of sulfuric acid solution and another flushing tank, finally enter the addition tank filled with acrolein, formic acid and copper acetate in advance, heat and stir to keep the reaction temperature at 35-41 °C. When the reaction is approaching the end point, the reactant is light yellow and mixed with flocs, and its relative density is measured from time to time. When the relative density is 1.066-1.074 (20°C), it indicates that the reaction has reached the end point. In 3-methylthiopropanal.
Feed according to the ratio of 3-methylthiopropanal, sodium cyanide, and ammonium bicarbonate at a ratio of 1:0.52:1.75. After dissolving ammonium bicarbonate in water 4 times its weight and sodium cyanide in water 3 times its weight, respectively, put them into a reaction tank, slowly add 3-methylthiopropionaldehyde dropwise under stirring, and keep warm for 75 React at -80°C for 3 hours to obtain ureide.
Hydrolyze 1.1 parts of lime to make lime milk, take another 0.424 parts of sodium hydroxide solution and put it into the reaction tank, add 1 part of ureide, heat up for alkali hydrolysis and discharge ammonia for 1 hour, keep warm at 165°C and pressure 0.5MPa, and react 1h, to obtain DL-methionine sodium salt.
Neutralize and decolorize the above-mentioned DL-methionine sodium salt with HCl to adjust the pH to 5-6, boil with 1% activated carbon for 45 minutes, filter while hot to remove residue, collect the filtrate, cool and crystallize, filter to obtain crystals, and dry at 100°C to obtain crude DL-methionine .
For refining, feed the crude product, distilled water, activated carbon, and EDTA in a ratio of 1:7:0.04:0.0007, put it into the refining tank, stir, decolorize for 1.5h, filter to remove residue, collect the filtrate, cool and place for 15-20h to crystallize, The crystals were collected by filtration and dried to obtain the finished product of DL-methionine.

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