Ch. 5 Quiz Flashcards
(22 cards)
Give one example of extraction in everyday life.
Brewing tea and making coffee involve solid/liquid extraction
Type of extraction that is most common when isolating natural products.
Solid/liquid extraction
Quenching
The addition of a solution that deactivates the reagents involved in the reaction
Distribution (Partition) coefficient
The ratio of the solubility of the solute dissolved in the organic layer to the solubility of the material dissolved in the aqueous layer (organic/water)
Factors that should be considered when choosing a solvent for liquid/liquid extraction
Cost, toxicity, volatility and flammability
Density of non-halogenated and halogenated solvents compared to water
Non-halogenated are less dense than water while halogenated solvents are more dense than water
Drop test
A test conducted to determine which layer is on top of the other. Add in a few drops of water and watch what happens - if the drops dissolve then the aqueous layer is on top and if the drops do not dissolve, they will form a second layer so it is the organic layer
Washing
The removal of traces of unwanted materials by extracting the organic layer in the separatory funnel with pure distilled water
Purpose of sodium sulfate
Sodium sulfate is used because it will removed trace amounts of any remaining water thus isolating the organic compound
Crude product
By-product
Emulsion
A suspension of tiny droplets of one solvent mixed in the other
Pros and cons of using sodium metal as a drying agent
Pro: good drying agent
Con: violently decomposes in water to create sodium hydroxide and hydrogen case which may spontaneously ignite
Carboxylic acid
Reacts with NaOH or NaHCO3
Phenol
Reacts with NaOH
Amines
React with HCl
Why is the melting point of a compound lowered when impurities are present?
When a compound contains impurities, they disrupt the ordered crystalline structure of the compound. As a result, the compound becomes amorphous and the attractive forces that hold the crystal lattice have been weakened
Eutectic temperature
The lowest temperature at which the mixture will begin to melt
Eutectic point
The mole percentage where the mixture of two compounds are dissolved equally in each other
Relationship between melting point and substance purity
The purer the compound, the narrower the melting point range
The more impure the compound, the broader the melting point range
Dyes used in procedure 1
Toluidine blue: blue in acid
Bromocresol purple: purple in base
Quinoline yellow: yellow in neutral
Possible unknowns for acid/base extraction in procedure 2
Benzoic acid/3-toluic acid
4’-aminoacetophenone/3’-aminoacetophenone
1,4-dimexthoxybenzene/fluorenone
The three main parts of procedure 2
Separation of the basic component by extraction with an acid
Separation of the acidic component by extraction with a base
Isolation of the neutral component
