CAS 52-90-4 | L-Cysteine

Products Description

L - Cysteine has a CAS number of 52 - 90 - 4. It has multiple chemical names, such as L - 2 - amino - 3 - mercaptopropionic acid, β - mercapto - α - aminopropionic acid, 3 - mercaptoalanine, etc. Its molecular formula is C₃H₇NO₂S, and its molecular weight is about 121.16.

It appears as a white crystal or crystalline powder, presenting as a colorless to white fine columnar crystal, with a slightly special smell and taste. Its melting point is about 240℃, belonging to the monoclinic system, but there are also documents stating the melting point is 220℃ (decomposition). Its density is about 1.197, and it is also recorded as 1.3±0.1g/cm³. It is highly soluble in water, with its aqueous solution being acidic. It is scarcely soluble in ethanol and insoluble in organic solvents such as ether, acetone, benzene, carbon disulfide, and chloroform. Its specific rotation is +8.3°～+9.5°, and it is also recorded as 8.75° (c = 12, 2N HCl).

Basic Info

Preparation method

Tin-grain reduction method: Dissolve cystine in dilute hydrochloric acid, filter, add tin grains to the filtrate, and reflux for 2 hours. Dilute the reduction solution with water, remove the remaining tin grains, pass hydrogen sulfide to saturation, filter, wash the filter residue with a small amount of water, combine the washing and filtrate, concentrate under reduced pressure, cool to crystallize, and then filter and dry to obtain L - Cysteine.

Electrolytic-reduction method: Add distilled water, hydrochloric acid, and cystine to the electrolytic tank and stir to dissolve. Maintain the temperature below 50℃ and electrolyze until the endpoint. Pass hydrogen sulfide through the obtained electrolyte for several hours and filter. Add activated carbon to decolorize the filtrate, filter, concentrate under reduced pressure, cool to crystallize, and then filter and dry to obtain L - Cysteine.

Protein-hydrolysis method: It can be obtained by hydrolyzing proteins like human hair with hydrochloric acid, followed by treatment with copper oxide and decomposition with hydrogen sulfide.

Uses

Medical field: It is mainly used in liver medicine, detoxification medicine, expectorant medicine, etc. It can be applied to liver-poisoning detoxification, antipyretic and analgesic treatment, ulcer treatment, fatigue recovery, infusion, and comprehensive amino-acid preparations. It is particularly effective for expectoration, treating bronchitis, and promoting sputum discharge.

Food field: It serves as a bread-fermentation promoter, preservative, antioxidant, and stabilizer for milk powder and juice, as well as a nutritional additive for pet food. It can accelerate gluten formation and prevent aging. When used in natural juice, it can prevent VC oxidation and browning.

Cosmetic field: It is used to produce perm essence, sunscreen, perfume, hair-care essence, etc. It can substitute for thioglycolic acid, featuring easy perming, stable hairstyles, and soft-textured hair. It can also be used to formulate sunscreen and hair-growth perfume.

Company Profile

Gneechem, located in Henan Province, China, is part of the GNEE Group, with 22 years of experience in foreign trade, specializing in providing high-quality chemical raw materials and professional trading services to customers around the world. We supply basic chemical raw materials, fine chemicals and specialty chemicals for a wide range of industries.We are ISO9001 certified and have been recognized by a number of authoritative qualifications at home and abroad, making us a trusted partner of our customers.

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