| Most of bromides are important fine organic chemicals and flame retardant. These products are developing very fast because of their wide usage. The preparation methods of high purity and high yield of p-bromophenol and 2,4,6-tribromophenol by selective orientation bromination of phenol were studied. The influence of solvents, temperature, time and the ratio of materials on effects of orientation in mon-bromination and tri-bromination of phenol were detected. The effect factor and optimum condition of mon-bromination and tri-bromination of phenol can be determined by orthogonal experiments each. The structure of p-bromophenol and 2,4,6-tribromophenol was charactered by IR, 1H-NMR, MS and Elementary Analysis. The melting point and the content of bromine of 2,4,6-tribromophenol were determined. The purity analysis was gained by gas chromatography. The optimum condition of preparation of p-bromophenol by mon-bromination of phenol are as follows: ethyl acetate solvent, 1.1 of the mole ratio of bromine to phenol, 0.59 of the mass ratio of bromine to solvent, 1.04 of the mass ratio of phenol to solvent, -10℃of the reaction temperature, 120 minutes of the time of titration bromine. The optimum condition of preparation of 2,4,6-tribromophenol by tri-bromination of phenol are as follows: 3.1 of the mole ratio of bromine to phenol, 40 of the volume percentage of methylene dichloride in methylene dichloride-water solvent, 40℃of the reaction temperature, 150 minutes of the reaction time. |
