Organic analysis/NMR

Test for primary, secondary and tertiary alcohols

1• →aldehyde (distillation) →carboxylic acid (reflux)

2•→ketone (reflux) can’t oxidise further

3•→ doesn’t oxides

Distinguish between aldehyde and ketone

Fehlings solution → aldehyde blue solution to brick red ppte

Tollens reagent → aldehyde silver mirror

Ketone = NVC for both

Test for Acids

Sodium carbonate → effervescence

Further test CO2 → limewater turns cloudy

Test for Alkanes and Alkenes

Bromine water → alkene goes orange to colourless

Greenhouse gasses what are they good at absorbing

CO2, water vapour and methane

Absorbing infrared energy

Explain greenhouse gasses

Short wavelength emitted from sun entering the atmosphere and reflected as longer wavelengths. The greenhouse gasses absorb these and reradiate in all directions warming the earth

Fingerprinting region

Below 1500

Unique to compound, compare to a database or known pure sample

Test for purity

Nuclear environment

Atoms environment depending on the atoms/groups it’s bonded to

NMR measures

Difference is called

Energy absorbed by different nuclei in the different environment relative to a standard substance

difference is called chemical shift

What is the standard substance

TMS (tetramethylsilane) Si(CH3)4

Why is TMS used

All H and C are in same environment

Only 1 absorption at delta=0

Inert, non toxic, low bp so it can easily be removed from sample

If sample needs to be dissolved in

Proton free solvent

Two types of proton free solvent

CCl4 - non polar so dissolves non polar molecules (or deuteratred solvents)

CDCl3 - polar so dissolved polar molecules

Splitting pattern