Preparation of methyl 3-nitrobenzoate in two steps

The idea behind this experiment is to show that many industrial preparations (in the pharmaceutical industry, for example) involve sequences of chemical reactions.

Step 1 Formation of the ester, methyl benzoate

This involves the same reaction we used to make esters in experiment 4.8.3d*. We shall be using the techniques of reflux, solvent extraction and distillation.

Work out the percentage yield of this first stage based on the 8 g starting mass of benzoic acid. The yield of methyl benzoate is given in the video.

Video - the preparation of methyl benzoate

Percentage yield calculation

Step 2 The nitration of methyl benzoate

In this second stage, the methyl benzoate made in part one was nitrated using a mixture of concentrated nitric and sulfuric acids. Write down an equation showing the formation of the main product, methyl 3-nitrobenzoate. Suggest why it is important to keep the temperature below 15 ºC. Check your answers below.

Video - the nitration of methyl benzoate

The product purity was checked using thin layer chromatography and by measuring its melting point.

Video - thin layer chromatography

Theory - the nitration of methyl benzoate