PROPAN-2-OL-2-丙醇、异丙醇

PROPAN-2-OL Prepared at the 51st JECFA (1998), published in FNP 52 Add 6 (1998) superseding earlier specifications prepared by the 28th JECFA (1984), published in FNP 31/2 (1984) and republished in FNP 52 (1992). No ADI allocated at the 25th JECFA in 1981. SYNONYMS Isopropyl alcohol, isopropanol DEFINITION Chemical names 2-Propanol, propan-2-ol C.A.S. number 67-63-0 Chemical formula C3H8O Structural formula CH3CHOHCH3 Formula weight 60.10 Assay Not less than 99.5% of C3H8O DESCRIPTION Clear, colourless, mobile liquid with a characteristic odour FUNCTIONAL USES Extraction solvent, carrier solvent, flavouring agent (see "Flavouring agents" monograph) CHARACTERISTICS IDENTIFICATION Solubility (Vol. 4) Miscible with water, ethanol, ether and other organic solvents Specific gravity (Vol. 4) d2020: 0.784 - 0.788 Refractive index (Vol. 4) n20D: 1.377-1.380 PURITY Water (Vol. 4) Not more than 0.2% (Karl Fischer Method) Distillation range (Vol. 4) Within a range of 1o including 82.3o Warning: Check first for Peroxides Non-volatile residue (Vol. 4) Not more than 2 mg/100 ml Acidity Not more than 0.002% (as acetic acid) Add 2 drops of phenolphthalein TS to 100 ml of water, add 0.01N sodium hydroxide to the first pink colour that persists for at least 30 sec, then add 50 ml (about 39 g) of the sample and mix. Not more than 0.7 ml of 0.1N sodium hydroxide is required to restore the pink colour. Other alcohols, ethers and Not more than 0.5% total, with not more than 0.1% of any single ethers. volatile impurities See under METHOD OF ASSAY Lead(Vol. 4) Not more than 1 mg/kg Determine using an atomic absorption technique appropriate to the specified level. The selection of sample size and method of sample preparation may be based on the principles of the method described in Volume 4, “Instrumental Methods.” . METHOD OF ASSAY Determine the content of propan-2-ol and volatile impurities using the procedures for gas chromatography under the following conditions: Column - length: 1.8 m - diameter: 6 mm - material: steel - packing: 10% P.E.G. 400 on Chromosorb W (60/80 mesh), or equivalent Carrier gas: Helium Flow rate: 45 ml/min Detector type: FID Temperatures - injection port: 150o - column: 90o - detector: 150o Inject 1 to 5 µl of sample, obtain chromatogram and determine content of each constituent by the method of area normalization. PROPAN-2-OL SYNONYMS DEFINITION Chemical names C.A.S. number Chemical formula Structural formula Formula weight Assay DESCRIPTION FUNCTIONAL USES CHARACTERISTICS IDENTIFICATION PURITY Acidity Other alcohols, ethers and volatile impurities METHOD OF ASSAY Column