Organic Chemicals and Polymers

 

2,4-DNP – Use 2,4-dinitrophenylhydrazine and a carbonyl compound to show formation of the 2,4-DNP product (acetone, cyclohexanone, and/or benzaldehyde).

Aldol Condensation – Show the reaction between acetone and cinnamaldehyde in base, which results in a mixed aldol condensation that produces a yellow precipitate.

Basicity of Amines – Add an amine to an indicator solution to demonstrate its basicity.

Benedict’s Test – Use Benedict’s solution and dextrose to demonstrate Benedict’s test for aldehydes. Different sugars available upon request.

Carboxylic Acid Conversion – Demonstrate the conversion of water-insoluble p-chlorobenzoic acid to its soluble salt and reconversion to the acid by adding first NaOH, then HCl.

Disappearing Styrofoam Cup – Make a styrofoam (expanded polystyrene) cup disappear by placing it in a dish of acetone.

Hydrolysis of Alkyl Halides – Demonstrate the effect of the leaving group on the rate of an SN1 reaction easily and colorfully on the overhead projector by comparing the rates of hydrolysis of tert-butyl chloride and tert-butyl bromide in the presence of mixed indicators.

Miscibility and Immiscibility – Mix ethanol and colored water in one beaker and hexane and colored water in another to demonstrate miscibility and immiscibility due to differences in the intermolecular forces of alcohols as the size of the alkyl group increases. The demo can be repeated with octanol and water, to show that, as carbon chain length increases, polarity of alcohols decreases.

Nylon 6-10 – Demonstrate the polymerization of hexamethylenediamine with sebacoyl chloride to produce the polyamide Nylon 6-10.

Oxidation of Alcohols – Demonstrate the oxidation of ethanol with K2Cr2O7 on the overhead projector; the alcohol solution changes from orange to green to blue as the Cr(VI) is reduced; this reaction is the basis for the Breathalyzer test.

Polarizing Filters and Limonene – Place small beakers of (R)-(+)-limonene and (S)-(-)-limonene between two polaroid sheets on the overhead projector to show the equal but opposite rotation of plane-polarized light by these enantiomers; you can also show that a racemic mixture does not rotate polarized light.

Production and Combustion of Acetylene – Add CaC2 to water to generate C2H2 (g), then ignite the gas.

Reactions that Distinguish Alkenes from Alkanes – On the overhead projector, demonstrate the reaction of octane and octene with both Br2 in dioxane and KMnO4, and observe how the presence of a double bond and the stability of the carbocation affects the reactions.

Slime! – Make a cross-linked gel by mixing solutions of polyvinyl alcohol and borax; use this demo to relate concepts such as polymers and hydrogen-bonding to a commercial product students are familiar with.

Vapor Pressure – Evaporation – Show the effect of intermolecular forces on vapor pressure by letting three students make streaks of water, methanol, and acetone on the blackboard and then observing the relative rates of evaporation.