E 337 ROCHELLE SALT / SEIGNETTE SALT
CAS REG N° 304-59-6
L-2,3-Dihydroxybutabedioic Acid
Appearance : white, crystalline powder, or colourless, transparent crystals.
Solubility: very soluble in water, practically insoluble in alcohol.
DEFINITION
Potassium sodium (+)-(2R,3R)-2,3-dihydroxybutanedioate tetrahydrate.
Content : 98.0 per cent to 101.0 per cent (anhydrous substance).
Translucent tetrahydrate crystals. Melting point 70°-80°C. At 100°c it loses three molecules of water; it becomes anhydrous at 130°-140°C; at 220°C it starts to decompose.
Soluble in 0.9 parts of water. The watery solution is weakly alkaline.
IDENTIFICATION
It complies with the test for specific optical rotation
It gives reaction of tartrates
It gives reaction of potassium
It gives reaction of sodium
DENSITY (25°C):
SOLUBILITY IN WATER:
pH VALUE (1.47 g/ml of H2O, 25°C):
MELTING POINT:
1,1 g/ml
1,47 g/ml of H2O
6,5 - 8,5
Between 70 and80°C