exp 1 isolation

Cellulose

serves as a rigid and insoluble structural element

Caffeine

alkaloid, a class of naturally occurring compounds containing N and having the properties of an organic amine base

Tannins

polyphenolic compounds (having OH on aromatic ring) with molecular weight of 50- 20,000

Tannins

soluble in water and therefore extracted from the leaf and responsible for the typical bitter taste of tea

Tannins

their presence in tea leaves complicates the isolation of caffeine since low molecular weight tannins are also soluble in DCM

flavonoid pigments

brown color of a tea solution is due to _______ and chlorophylls and to their respective oxidation products

extraction

Separation of components by extraction depends upon the difference in solubility of a compound in two mutually insoluble phases

solid-liquid extraction

or leaching, is a separation process that removes soluble components from a solid matrix using a liquid solvent.

liquid-liquid extraction

or solvent extraction, is a separation technique that moves a compound from one liquid solvent to another based on different solubilities, using two immiscible liquids (typically organic and aqueous)

Boiling chip

small, lump of porous material generally made from pieces of pumice, carborundum, or marble that produces a steady stream of fine air bubbles when it is heated into a solution

Ca(OH)2

basic salt is added to the water solution so that tannins can react to it and form a salt that is insoluble in organic solvents such as DCM but is soluble in water

Vacuum Filtration

Receiver flask with side-arm, filter flask is used; Side-arm is connected by heavy-walled rubber tubing to a source of vacuum

Buchner funnel

Is sealed to the filter flask by a rubber stopper or a rubber gasket (Neoprene adapter) cone; Flat bottom is covered with an unfolded piece of circular filter paper which is held in place by suction

Hirsh funnel

used for smaller quantities of solid materials

Bernoulli effect

The _________ causes a reduced pressure along the side of the rapidly moving water stream and creates a partial vacuum in the sidearm

Dichloromethane

is an organic compound with the formula CH2Cl2; colorless, volatile liquid with a moderately sweet aroma; widely used as a solvent

Emulsions

A colloidal suspension of one liquid in another

Distillation

process of vaporizing a substance, condensing the vapor, and collecting the condensate in another container

Boiling point

The vapor pressure of the liquid increases to the point where it just equals the applied pressure, atmospheric pressure