Nitration of p-Anisaldehyde

In any organic chemistry class, students are faced with learning functional group transformation where the emphasis is placed on the effect of temperature on various chemical reactions. However, in a laboratory setting students rarely receive any practical hands-on experience in observing this effect. In this laboratory experiment, students nitrate p-anisaldehyde at –15 to –8℃ and from 25 to 40℃ using a nitric acid/sulfuric acid solution. Gas Chromatography/Mass Spectroscopy (GC/MS) analysis of the reaction mixture at a lower temperature range revealed a single compound, 4-methoxy-3-nitrobenzaldehyde (1), while GC/MS analysis of the reaction mixture at the higher temperature range revealed 4-methoxy-3-nitrobenzaldehyde (1) as the major product and three additional by-products – 2-nitroanisole (2), 4-methoxy-3,5-dinitrobenzaldehyde (3), and 2,4-dinitroanisole (4). This laboratory experiment can be used as a template for complementing undergraduate laboratory experiments that exclude the qualitative or quantitative effect of temperature on product distribution.