University:
Eastern Kentucky University
Course:
CHE 361 | Organic Chemistry I
Academic year:

2020
Views:

342

Pages:

1
Author:

Trevon Bernard

Organic Chemistry 12: Separations and Purification Solubility-Based Methods Extraction: Combines two immiscible liquids, one of which easily dissolves the compound of interest. Nonpolar Layer: Organic layer, dissolves nonpolar compounds. Polar Layer: Aqueous (water) layer. Dissolves compounds with hydrogen bonding or polarity. Wash: The reverse of an extraction. A small amount of solvent that dissolves impurities is run over the compound of interest. Filtration: Isolates a solid (residue) from a liquid (filtrate) Gravity Filtration: Use when the product of interest is in the filtrate. Hot solvent is used to maintain solubility. Vacuum Filtration: Used when the product of interest is the solid. A vacuum is connected to the flask to pull the solvent through more quickly. Recrystallization: The product is dissolved in a minimum amount of hot solvent. If the impurities are more soluble, the crystals will reform while the flask cools, excluding the impurities. Chromatography * See appendix for detailed information Separates two or more molecules from a mixture. Includes liquid chromatography, gas chromatography, size-exclusion chromatography, ion-exchange chromatography, affinity chromatography, and thin-layer chromatography. Distillation Distillation: Separates liquids according to differences in their boiling points. The liquid with the lowest BP vaporizes first and is collected as the distillate. Simple Can be used if the boiling points are under 150°C and are at Distillation: least 25°C apart. Vacuum Should be used if the boiling points are over 150°C to Distillation: prevent degradation of the product. The vacuum lowers the air pressure, which decreases the temp the liquid must reach in order to boil. Fractional Should be used if the boiling points are less than 25°C apart Distillation: because it allows more refined separation of liquids by BP. Most Experiments Organic on top Aqueous on bottom Extraction: Polar solutes dissolve in the aqueous layer. Non-polar solutes dissolve in the organic layer.