L-Proline CAS 147-85-3 for Food Grade

Product Name:L-Proline
CAS NO.: 147-85-3
Appearance:White crystalline powder
Product Properties: Have strong sweet, almost odourless. Melting point 222 ℃ (decomposition). Easily soluble in water (162. 3%, 25 ℃), soluble in ethanol, insoluble in ether and butanol, easy deliquescence, crystallization is not easy to get.

Product Detail


L-Proline is one of important amino acids which form protein in human boby. It is the essential material of amino acid transfusion. And it is also the main intermediate for compounding Captopril, Enalapril and other antihypertensive drugs. It has been widely used in food, medicine and other industries. It is made by fermentation of corn. So it is more safer.

1. Used as nutritional supplement.

2. Used as the materials of compound amino acid infusion. Used in malnutrition, protein deficiency disease, stomach disease, scald and protein supplement after surgery.

There are two kinds of L – proline. One is direct fermentation, using glucose and yellow short bacillus mutant or glutamic acid bacillus wild strains, L – proline obtained with microbial fermentation; 2 it is chemical synthesis to glutamic acid as raw materials, and anhydrous ethanol under the sulfuric acid catalytic esterification, and add triethanolamine to amine sulfate free, glutamic acid – delta – ethyl ester. Reoccupy metal reductant glutamic acid potassium borohydride reduction – delta – ethyl ester, raw proline, finally the purification can be rough on the proline. Small craft take L – glutamic acid esterification said 147 g, into three bottle neck, add 1 L, anhydrous ethanol mix cool to 0 ℃, and then add 80 ml – H2SO4, at 0-5 ℃ stirring reaction 1 h, 1 h at room temperature to continue response, response all clear. Under 20 ℃ and triethylamine to pH 8-8.5, precipitation white crystalline, 1 h at room temperature and stirring, let stand for 5 ℃ cooling filtration, crystallization, washing with 95% ethanol, drained after vacuum drying, to glutamic acid ethyl – delta – about 141 g. Melting point of 178-180 ℃, the yield of 80% 83%. [alpha] 32 + 29.8 d (C = 1 g/ml 10% HCl). Reduction in three flask into glutamic acid ethyl – delta – 175 g, add distilled water, 875 ml, stir cool to 5 ℃, add in another KBH4 53.9 g, about 1 h adds, at room temperature and 1 h reaction, heat preservation 50 ℃ reaction 3 h. Cooled to 0 ℃, add 6 mol/L HCl to pH4, filtering the filtrate, quick rough L – proline aqueous solution. Ion exchange resin – alumina column chromatography separation and purification raw will L – proline aqueous solution, with 4 ml/min flow entering into the 732 – H + resin exchange column charge 10 ml acid resin (1 g). First rinse with distilled water to neutral, then use 1 mol/L ammonia elution, collection of L – containing proline eluent (thin layer chromatography with silica gel G control). Condensed the eluent decompression to dry, then use a small amount of water dissolves, it into neutral alumina column, again with 60% ethanol elution solution (or a thin layer chromatography with silica gel G control).


Item AJI92 EP8 USP36
Assay 99.0% ~ 101.0% 98.5% ~ 101.0% 98.5% ~ 101.5%
PH Value 5.9 ~ 6.9
Specific Rotation -84.5° ~ -86.0° -84.0° ~ -86.0° -84.3° ~ -86.3°
Transmittance ≥98.0% clear & colorless
Chloride(as Cl) ≤0.02% ≤0.02% ≤0.05%
Ammonium(as NH4) ≤0.02% ≤0.02%
Sulfate(as SO4) ≤0.02% ≤0.03% ≤0.03%
Iron(as Fe) ≤10ppm ≤10ppm
Heavy metal(as Pb) ≤10ppm ≤10ppm ≤15ppm
Arsenic(as As) ≤1ppm
Other amino acids conform conform conform
Loss on drying ≤0.30% ≤0.50% ≤0.40%
Residue on ignition ≤0.10% ≤0.10% ≤0.40%
Ninhydrin-positive substances conform

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