Preparation of n-Butyl Cyclopropanecarboxylate

The chemistry you will use is outlined below:

A nice reference concerning this class of cyclization: https://dx.doi.org/ 10.1016/S0040-4020(01)01134-6. (On-campus or VPN/proxy access required)

• The chlorobutyronitrile is of the same chemical class as iodomethane, so keep it in the fume hood, try not to spill it, and use gloves throughout the experiment.
• Powdered sodium hydroxide is very caustic; it is also extremely hygroscopic (it absorbs water from the atmosphere).  Take care not to spill it, and transfer it to your reaction flask as quickly as possible.
• The organic compounds used in this experiment are volatile and have disagreeable odors, so avoid keeping open containers of any of these outside the fume hood.
• Addition of water to hydrolyze the nitrile causes a large amount of heat as the excess NaOH dissolves.  Add water in 5-mL increments at first to avoid excessive heat buildup.

Grading:

• You should calculate the yield of pure carboxylic acid from chlorobutyronitrile.
• You should calculate the yield of butylcyclopropanecarboxylate from cyclopropanecarboxylic acid.
• You should then calculate the overall yield, which is the product of the two individual yields.

• Your refractive index for the ester should match the literature value (1.4260 ± 0.0003 at 25°C); an acceptable temperature-corrected value will be within ±.0005 of this.
• You should take IR spectra of both the carboxylic acid and the ester; you need to identify any peaks in the functional group region, and establish that the fingerprint region matches that of a reference spectrum.
• You should demonstrate with gas chromatography that the purity of the liquid ester is >99%.  If the butanol peak is >1% the area of the ester peak, you must redistill.  Be sure you have confirmed the retention time of each compound, and that the GC needle is not contaminated!
• You will need to report the boiling range and pressure for each compound; this, like melting points of solids, is a characteristic physical property.