[PRACTICAL] O Chem Synthesis

[APPARATUS]

Explain the purpose of using a hot plate to heat organic reactants.

[APPARATUS]

Explain the purpose of using a hot plate to heat organic reactants.

To avoid direct heating because organic substances are typically flammable.

[APPARATUS]

Explain the use

[APPARATUS]

Explain the function of boiling chips

Ensure more even boiling

[APPARATUS]

Explain the purpose of placing a magnetic stirrer in the reaction mixture.

To ensure a homogenous reaction mixture

[SEPARATION]

Briefly describe how you would separate two immiscible liquids from an aqueous reaction mixture

1. Upon introducing the organic solvent into the reaction mixture, it is poured into a separating funnel

2. Shake the mixture and leave to stand

3. Open the tap to drain off the denser layer of liquid. Close the tap one the phase boundary reaches the tap.

4. Pour out the less dense layer form the mouth

5. Repeat steps 2 to 4, adding new portions of the organic solvent to the aqueous layer

[PURIFICATION]

Describe how you would obtain a pure sample of solid organic product.

1. Add minimum quantities of an appropriate hot solvent gradually in small volumes to dissolve the impure solid organic product and obtain a hot saturated solution. (The solid should be soluble in this solvent at high temperatures but insoluble/sparingly soluble at low temperatures. Impurities should be very soluble in this solvent. )

2. Let the saturated solution cool at room temperature/in an ice-water bath to allow crystallisation

3. Obtain the purified organic crystals via vacuum filtration

4. Dry the organic crystals in a desiccant or with a drying agent

[PURIFICATION]

How would you verify the purity of the sample obtained?

Place a small amount of sample into a melting/boiling point capillary tube and determine its melting/boiling point using melting/boiling point apparatus. If the sample is pure, the melting/boiling point will be about (value given) and melting/boiling would be completed within a very small temperature range.

List some drying agents

1. Silica gel

2. Activated alumina

3. Anhydrous CaCl2

4. Anhydrous MgSO4

5. Anhydrous CaSO4

6. Anhydrous BaO

[SAFETY PRECAUTIONS]

For flammable chemicals

1. Ensure no open or naked flame in lab

2. Switch off Bunsen burner prior to experimental work

[SAFETY PRECAUTIONS]

For irritants/toxic/corrosive chemicals

1. Wear safety goggles and gloves to minimise contact with skin and eyes

2. Conduct experiment in a fume hood to minimise inhalation

3. Avoid spillage

[SAFETY PRECAUTIONS]

For harmful gas or vapour

Conduct experiment in a fume hood to minimise inhalation

[SAFETY PRECAUTIONS]

How can you safely conduct a violent/highly exothermic reaction?

1. Immerse the reaction flask in an ice-water bath

2. Add reagents dropwise