16) Organic Synthesis

To allow a reaction mixture to be heated at its boiling point for an extended period without losing volatile reactants, products, or solvent. The condenser cools vapours, causing them to drip back into the flask.

Round-bottom/pear-shaped flask, condenser, rubber tubing (for water), stand and clamp, heat source (Bunsen burner, heating mantle, or water bath).

To promote smooth, even boiling by providing nucleation sites for bubble formation, preventing violent bumping or jumping of the liquid which could damage glassware.

Water enters at the bottom inlet and exits at the top outlet. This ensures the condenser jacket is completely filled with cold water, maximizing cooling efficiency for vapour condensation.

It creates a closed system. Heating causes air and vapours to expand, building dangerous pressure that can lead to the apparatus exploding.

To create a good seal that prevents leaks and allows the joints to be easily separated after the experiment without sticking or breaking.

To separate and purify a desired liquid product from its reaction mixture (including unreacted starting materials, solvents, or by-products) based on differences in boiling points.

Round-bottom/pear-shaped flask, still head, thermometer, screw-cap adaptor, condenser, receiver adaptor, receiver flask, rubber tubing, stand and clamp, heat source.

To provide stable support and remove the need to clamp the fragile glass condenser itself, reducing the risk of breakage.

Add a small amount of water to the mixture. The layer that increases in volume is the aqueous layer; the other is the organic layer.

A separating funnel.

• Close the tap. 2. Pour mixture in and stopper. 3. Invert and shake gently (vent pressure if needed). 4. Allow layers to settle. 5. Identify aqueous layer (by adding water). 6. Place flask under tap and drain lower layer. 7. Collect upper layer separately.

To neutralize and remove any acidic impurities (e.g., excess sulfuric acid or HBr). The reaction produces carbon dioxide gas (CO₂), which is released by venting the funnel.

Anhydrous calcium chloride (CaCl₂), anhydrous calcium sulfate (CaSO₄), anhydrous magnesium sulfate (MgSO₄).

When some of the solid drying agent remains as a fine powder dispersed in the liquid (not clumped together). Clumping indicates water is still present.

Redistillation is a second distillation of a previously distilled product. It is done to further purify the compound by collecting only the fraction that boils within a very narrow range around the known boiling point of the target compound.

The specific organic compound that a chemist aims to prepare using a series of chemical reactions from simpler starting materials.

A method of synthesizing a target molecule in two distinct chemical steps, involving an intermediate compound formed in the first step and converted to the final product in the second step.

Stage 1: NaOH(aq), reflux → Propan-1-ol Stage 2: K₂Cr₂O₇/H₂SO₄, distil → Propanal

Stage 1: Steam (H₂O(g)), H₃PO₄ or H₂SO₄ catalyst → Butan-2-ol Stage 2: K₂Cr₂O₇/H₂SO₄, reflux → Butanone

To cleave (break open) a carbon-carbon double bond (C=C) to produce carbonyl compounds (aldehydes or ketones). Useful for determining structure or synthesizing specific fragments.

Ethanal (CH₃CHO) and Propanal (CH₃CH₂CHO)

Flammable liquid; vapours can form explosive mixtures with air.

Because 1-bromobutane has a boiling point of 102°C. This range captures the desired product while minimizing collection of lower-boiling impurities (like water or ethanol) or higher-boiling ones (like unreacted butan-1-ol).