Benzoic Acid Synthesis

This experiment was conducted to practice a variety of techniques in organic chemistry: separation, mechanisms, acid-base reactions, evaporation, recrystallization, and identification. The goal of this experiment was to identify the unknown mixture of two compounds. The two compounds were separated first by altering the acid components solubility through deprotonation, and then protonating the acid component again to form the separated precipitate. The ether in the neutral layer was evaporated, and the residue was recrystallized. The crystals were subject to a melting point analysis, which involved identifying the melting point ranges on the unknown samples, and compared them to the ranges on known samples of possible compounds. The compounds that matched the sample were then tested through a mixed melting point that ensured proper identification and whether impurities were present in the isolated compounds. The compounds were found to be benzoic acid and benzoin. TLC was then conducted to determine if impurities were present. The IR spec was then conducted to ensure proper …show more content…
The mixed melting point for the benzoic acid brought down the range and broadened it, shown in Table 2, which indicated impurities, most likely in the known Benzoic acid because the separated benzoic acid had a narrow melting point range. M-toluic acid was also tested to be sure the compound was correctly identified. The neutral sample had a narrow melting point range, shown in Table 2, and was close to the known range of benzoin, shown in Table 1. The mixed melting point range was narrow, and close to that of the original sample, shown in Table 2, indicating that the correct compound was identified and there were minimal impurities. The purpose of the mixed melting point is to determine correct identification and impurities in the