Putification And Separation

Separates miscible liquids because some liquids are soluble in water- only works if liquids have different BPS • mixture of both heated to produce hot vapours • cold water enters condenser at lower end and leaves at higher • hot vapours rise and enter condenser, then cool condense and run into the beaker as a liquid • the lower BP boils first and vapours initially contain this, the higher BP remained behind in flask as a liquid

Same as simple distillation except a fractioning column is placed between the boiling flask and condenser- fitted with beads, beads improve the separation between the liquids being distilled

Used to remove high BP liquids from the reaction mixture- used for compounds that may decompose near their BPS- the liquid forms an insoluble layer with the condensed steam in the collecting flask. Separating funnel is then used to separate the 2 liquids

If compounds decompose at temps near their BPs then they should be distilled under reduced pressure. this means they’ll boil at lower temps, distillation apparatus is attached to vacuum pump which reduces pressure

When miscible liquids are selected from Escher and the compounds decompose at temps near their boiling points .

Sepeation done using a separation funnel. Funnel used to carry out a solvent extraction- this is the separation of a substance from one liquid into another. It must be immiscible and substance must be more soluble in one of the liquids

Immiscible liquids A substance must be more soluble in one of the liquids

Removal of insoluble solids from liquids- involves a filter funnel and filter pummel which is fluted (folded)- a Büchner funnel is normally attached to a vacuum pump via a splash back flask- called vacuum filtration

Pure: sharp MPS over a range of 1-2 degrees - this sharp MP can be used to eliminate many other compounds Impure: melt over larger range

If the identity of s compound is suspected, a small sample is mixed with a. Known pure sample. If the 2 are identical- there will be no change in the MP value If no, then one behaves as an impurity and the MP may be lowered and lose its sharpness

To purify solids - a solvent is found which will dissolve both the compound and impurities when hot but dissolves much less of the compound when cold Method: • find suitable solvent via looking at literature • dissolve sample in the minimum volume of hot solvent • filter hot (if necessary) to remove impurities, allow to cool and filter • wash sample with cold solvent and dry below MP This is necessary before weighing in order to give accurate yield of a pure product

Separates components in a mixture between a mobile phase and a stationary phase Limitations: 1-similar compounds have similar Rf values or retention times 2-Unknown compounds have no reference Rf values or retention times for comparison

The stationary phase is a thin layer of silica gel- spread over the surface of a thin glass plate. A small dot of sample solution is placed at the bottom of the plate Then placed in a . Jar containing shallow layer of solvent and is sealed Each dot is just above the solvent. The solvent is in its mobile phase and rises up the plate. The more soluble the solvent the further it travels The retardation factor for each component can be calculated via- Rf= distance moved by component / distance moved by solvent

Rf= distance moved by component / distance moved by solvent

By comparing the Rf value to standard compounds- this identifies the unknown substance

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To determine amino acids in blood samples or analyse food dyes

It identifies the percentage and number of compounds or impurities present in a sample

The mobile phase is a gas- it’s carried out in a column which contains the stationary phase. The sample is injected into the column The retention time for each component is identified- this is the time it takes for the component to pass from the column inlet to the detector The retention time is compared to standard compounds to identify an unknown substance. The peak area also gives the approximate percentage composition of the mixture - peak area is proportional to the amount of substance

This uses a solid stationary phase within a column. The mobile phase is a liquid and is passed through the column. The retention time for each component can be identified Retention time is then compared to standard compounds to identify the Unknown substance The peak area also gives the approximate % composition of a mixture- area under peak is proportional to amount of substance Can be used to isolate and purify compounds and determine the conc of a compound

Can be used to isolate and purify compounds and determine the conc of a compound

Compare retention times to standard compounds to identify an unknown substance

Identify number or percentage of compounds or impurities within a sample

1- the mobile phase is a gas, carried out in a column which contains stationary phase 2- he sample is injected into the column and retention time is taken for each component (retention time is the time taken for each component to pas from the column inlet to the detector) 3- retention time is compared to standard compounds to identify the unknown