| Name | Glycine |
| Synonyms | Glycine Glycine (Food Grade) Glycine (Feed Grade) Glycine (Tech Grade) Glycine (Pharm Grade) |
| CAS | 50-40-6 |
| EINECS | 200-272-2 |
| InChIKey | DHMQDGOQFOQNFH-UHFFFAOYSA-N |
| Molecular Formula | C2H5NO2 |
| Molar Mass | 75.07 |
| Density | 1.595 |
| Melting Point | 240 °C (dec.) (lit.) |
| Boling Point | 233°C |
| Flash Point | 176.67°C |
| Water Solubility | 25 g/100 mL (25 ºC) |
| Vapor Presure | 0.0000171 Pa (25 °C) |
| Appearance | Morphological powder, color <5 (200 mg/mL)(APHA) |
| pKa | 2.35(at 25℃) |
| PH | 4(0.2 molar aqueous solution) |
| Storage Condition | 2-8°C |
| Stability | Stable. Combustible. Incompatible with strong oxidizing agents. |
| Refractive Index | 1.4264 (estimate) |
| Physical and Chemical Properties | Chemical properties White monoclinic or hexagonal crystal, or white crystalline powder. It's odorless and has a special sweet taste. Soluble in water, solubility in water: 25g/100ml at 25 ℃; 39.1g/100ml at 50 ℃; 54.4g/100ml at 75 ℃; 67.2g/100ml at 100 ℃. It is extremely difficult to dissolve in ethanol, and about 0.06g is dissolved in 100g of absolute ethanol. Almost insoluble in acetone and ether. |
| Use | Used in the pharmaceutical industry, biochemical testing and organic synthesis, used as a buffer, used for the preparation of tissue culture media, copper, gold and silver testing, medically used for the treatment of myasthenia gravis and progressive muscle atrophy, hyperacidity, Chronic enteritis, children's hyperproline and other diseases. |
| Risk Codes | 33 - Danger of cumulative effects |
| Safety Description | S22 - Do not breathe dust. S24/25 - Avoid contact with skin and eyes. |
| WGK Germany | 2 |
| RTECS | MB7600000 |
| TSCA | Yes |
| HS Code | 29224910 |
| Toxicity | LD50 orally in Rabbit: 7930 mg/kg |
content analysis
accurately weigh about 175mg of the sample dried at 105 ℃ for 2h, put it into a 250m1 flask, add 50ml of glacial acetic acid to dissolve, add 2 drops of crystal violet test solution (TS-74), and titrate with 0.1ml/L perchloric acid to the blue-green end point. At the same time, blank test is carried out and necessary correction is made. Perchloric acid is equivalent to glycine (C2H5NO2)7.507mg per mL of 0.1mol/L.
Toxicity
LD507930 mg/kg (rat, oral).
can be safely used in food (FDA,& sect;172.812 2000).
use limited
As an amino acid source, it accounts for 3.5% of the total protein mass in food (FDA,& sect;172.320,2000).
as a bitter taste masking agent after adding saccharin sodium to beverage, limited 0.2% (calculated as finished beverage); As a stabilizer of single and double glycerides in edible oils and fats, limited 0.02%, measured by the amount of single and double glycerides (FDA & sect;172.812,2000).
FEMA: beverages, candies, baked goods, meat, sausage, broth and seasonings are all 150(mg/kg).
biosynthesis production of glycine
In the late 1980s, Mitsubishi Corporation of Japan added the screened aerobic Agrobacterium, Brevibacterium, Corynebacterium and other microbial genera to the medium containing carbon source, nitrogen source and inorganic nutrient solution for cultivation, and then converted ethanolamine into glycine at 25~45 ℃ and pH value of 4~9, and treated with concentrated neutralization ion exchange to obtain glycine.
after entering the 1990 s, new progress has been made in the synthesis of glycine abroad. Nitto chemical industry company of Japan added the cultured pseudocytellosis, casein, alcaligenes and other bacteria to the matrix containing glycine amine at 0.5% (mass fraction, dry weight), reacted at 30 ℃ and pH value of 7.9~8.1 for 45 hours, and almost all glycine amine was hydrolyzed to generate glycine, the conversion rate reached 99%. Although biological law is still in the research stage, it has high selectivity and no pollution, so it will be a synthetic route with great development potential.
Production method
glycine has no optical isomers, and all production adopts synthetic method. A brief introduction of the synthesis method is as follows.
(1) Streck (Strecker) method. Using formaldehyde, hydrocyanic acid and ammonia as raw materials, amino acetonitrile is synthesized first, and then glycine is generated in decomposition.
crude hydrocyanic acid is synthesized from methane and ammonia, then the formaldehyde solution continuously absorbs cyanic acid, then the reaction solution and ammonia are reacted at 120 ℃ for 2min to generate aminoacetonitrile, and finally alkali solution is added for hydrolysis to obtain glycine with a total yield of 87%.
(2)Bucherer method. Trioxymethylene was added to the aqueous solution of ammonium carbonate and sodium nitrile, stirred and dissolved at room temperature, and then reacted at 80-85 ℃ for 3 hours. An aqueous solution of hydantoin was obtained. Then 30% NaOH aqueous solution was directly added and hydrolyzed at 170 ℃ for 3 hours. Finally, it was treated with cation exchange resin to obtain glycine with 83.2% yield.
(3) Monochloroacetic acid ammoniation method. The ammonia water and ammonium bicarbonate were mixed and heated to 55 ℃, and the hydrolysis solution of monochloroacetic acid was added to react for 2 hours. Then the temperature is raised to 80 ℃ to remove the remaining ammonia and decolorize with activated carbon. After filtration, the filtrate is added with 95% ethanol to precipitate glycine. After separation, wash with ethanol. Coarse after drying. The crude product is dissolved in hot water and recrystallized with ethanol to obtain the finished product with a yield of about 42%.
(4) phase transfer catalysis. Add 2kg of ammonia water to 1L of methanol, then add 0.3kg of hexamethylenetetramine. After the solution is clarified, add 2L of methanol dissolved in 10kg of chloroacetic acid. The temperature of the system rises obviously. When it reaches 58 ℃, a large amount of crystallization precipitates. When the temperature drops to room temperature and the upper liquid is clarified, it is filtered to obtain crystallization, and the filtrate is left for 2 days, and part of the crystallization can be precipitated. Add 2-3 times the amount of deionized water to the crude product, heat to 70-75 ℃, add 2 times the volume of methanol after dissolution, cool and precipitate crystals, dry at 70 ℃ for 2 hours to obtain the fine product, the product yield is 68.6%, and the purity is 99.6%
| FEMA | 3287 | GLYCINE |
| Solubility | H2O: 100 mg/mL |
| Odor | Odorless |
| pH range of acid-base indicator discoloration | 4 |
| maximum wavelength (& lambda;max) | λ: 260 nm Amax: 0.05 λ: 280 nm Amax: 0.05 |
| JECFA Number | 1421 |
| Merck | 14,4491 |
| BRN | 635782 |
| NIST chemical information | Glycine(56-40-6) |
| EPA chemical information | Glycine (56-40-6) |