Chapter 16: Organic Synthesis

• Round bottomed/pear shaped flask • condenser • rubber tubing • stand and clamp • heat source: heating mantle (Bunsen burner, tripod and gauze may also be used but generally not the best when heating organic substances (especially if flammable))

Used for heating mixtures for a long time. Prevents the organic vapours from escaping due to the condenser.

• round bottomed/pear shaped flask • condenser • rubber tubing • heat source • stand and clamp • screw cap adaptor • receiver adaptor • still head • thermometer

Electric heaters (e.g. heating mantle) often used to heat organic chemicals, because organic chemicals are normally highly flammable and could set on fire with a naked flame

Anti-bumping granules added to prevent vigorous, uneven boiling by making small bubbles form instead of large bubbles

NEVER SEAL THE END OF THE CONDENSER - you’re creating a closed system as the build up of gas pressure could cause apparatus to explode. This is true of any apparatus where volatile liquids are heated.

A common method used to separate organic product from reacting mixture. Or just to separate a pure liquid from its impurities, with the liquid with the lowest boiling point evaporating first. (when vapour reaches the condenser, it becomes liquid again).

To connect the condenser to the tap for water

Water always enters the condenser at its lowest point

You can grease them lightly so that the apparatus comes apart easily after the experiment.

• put the distillate of impure product into a separating funnel • wash the product by adding sodium hydrogen carbonate solution, shaking and releasing the pressure from the co2 produced • add saturated sodium chloride solution • allow the layers to separate in the funnel, then run and discard the aqueous layer

nahco3 neutralises the remaining reactant acid

It helps separate the organic layer from the aqueous layer.

The layer with the lower density is the upper layer, which is usually the organic layer.

• run the organic layer into a clean, dry conical flask and add 3 spatula loads of drying agent and swirl • place a stopper to prevent product evaporation • if the solid is stuck together in a clump, water is still present. Add more drying agent until the solid is dispersed as a fine powder. • When dry the organic liquid should appear clear • Carefully decant the liquid into the distillation flask • Redistill to collect the pure product • on 2nd distillation, only collect the product at its boiling point

• because sometimes prepared sample may have some organic impurities • by distilling at boiling point exactly, you’re narrowing the range of impurities that may remain in your desired product

• Anhydrous calcium chloride (cacl2) used to dry hydrocarbons • anhydrous calcium sulphate, or anhydrous magnesium sulphate for general drying

It means carefully pour off the organic liquid, leaving the drying agent in the conical flask.

Preparation of complex molecules from simple starting materials.

• alkene: C=C • alcohol: -OH • haloalkane: -Cl, -Br, -I • aldehyde: - CHO • ketone: CC(O)C • carboxylic acid: -COOH • ester: -COO- • amine: -NH2 • acyl chloride: -COCl • nitrile: -CN

Reaction in which carboxylic acid reacts with an alcohol to form an ester and water. carboxylic acid + alcohol –> ester + water

Starting molecule: haloalkane Reagents: aqueous sodium hydroxide, NaOH (aq). The nucleophile is OH- Conditions: reflux Target molecule: alcohol Products: alcohol + water Type of reaction: hydrolysis Mechanism: nucleophilic substitution