Benzanilide-Thiourea Crude Mixture

The purpose of experiment 02 is to separate two solid compounds, benzanilide and thiourea, from a crude mixture, then verify the purification. The experiment is to be broken down into several stages: (a) In order to perform small-scale recrystallization, a suitable solvent must be selected. (b) The actual small-scale recrystallization is performed on the benzanilide-thiourea crude mixture. (c) Filtration of purified crystals. (d)Product recovery is calculated and measured. (e) In order to perform thin layer chromatography on the purified crystals, an effective eluent must be selected. (f) Thin layer chromatography is performed to assess the purity of the recrystallized product. (g) Melting point determination is performed in order to assess the purity of the recrystallized product. Benzanilide, C13H11NO has a carbonyl group so placed as to make the compound a ketone along with a secondary amine group in between two aromatic benzene rings. This chemical composition give the molecule certain characteristics of both the non-polar and polar compounds. Thiourea, a thioketone, SC(NH2)2, has a sulfur double-bonded to a carbon that is connected to two primary amine groups. This configuration gives thiourea a certain polarity …show more content…
The choice of solvent is of utmost importance in a recrystallization so three small scale recrystallization “pilot” experiments will be carried out prior to purifying a larger amount of material. For these experiments acetone ethanol and hexane will be tested as possible solvents for the bezanilide-thiourea crude mixture. The desired solvent will dissolve the impurity (thiourea), and partially dissolve the compound to be purified (benzanilide) so that when heated, the crude compound is completely dissolved and by cooling the solution the benzanilide will recrystallize in its pure form with the impurity staying