Synthesis of P-Bromoaniline
In this experiment, p-bromoaniline was synthesized in three steps starting from aniline. Since the amino group of aniline is a strong activator of aromatic ring, direct bromination is impractical (equation 1). In order to make a desired product, amino group needed to be protected as the acetamide which also maintained ortho and para position but slowed down the rate of reaction (equation 2). Slow reaction rate would increase the possibility of obtaining the para-position product (equation 3).
Crystallization should occur. When no more crystals seem to form (5—10 minutes), vacuum filter the acetanilide, wash the crystals with small volumes of cold water and air dry for 5 minutes. 5. Pure acetanilide is usually obtained as white flakes. Recrystallize the obtained acetanilide from a minimum of hot water. Use 10 ml of water to start and increase the amount of water depending on the amount of acetanilide. 6. If the initial crystals were not white, add 0. 5g of decolorizing charcoal to the product in water and then heat to gently boiling. 7. Remove the charcoal by hot gravity filtration ,using two pieces of fluted filter paper.