4-溴-2,3-二氟甲苯

反应条件: temp:-15.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: 2.67 g of aluminum tribromide and 16.0 g of bromine were added to 110 g of 4-fluorotoluene, which had been cooled to -15° C. After increasing the temperature to +10° C., hydrolysis was carried out with water, the mixture was extracted by shaking with methylene chloride and the methylene chloride phase was washed and dried. After distilling off the solvent and the excess 4-fluorotoluene, 5.5 g of a mixture consisting of 88% of 2-bromo-4-fluorotoluene, 8% of 3-bromo-4-fluorotoluene and 4% of dibromo-4-fluorotoluene were obtained at a boiling point of 172° to 184° C. (normal pressure). Relative to the 4-fluorotoluene reacted, the yield of 3-bromo-4-fluorotoluene was 2.3%. After increasing the temperature to +10° C. hydrolysis the mixture was extracted the methylene chloride phase was washed dried After distilling off the solvent

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: 11 g of iron powder were added to a solution of 110 g (1 mole) of 4-fluorotoluene in 165 ml of carbon tetrachloride. 160 g (1 mole) of bromine were added dropwise to this mixture at room temperature, the mixture was subsequently stirred for 24 hours, the solvent was distilled off under normal pressure and the residue was fractionated under normal pressure over a 10 cm Vigreux column. 26.4 g of unreacted 4-fluorotoluene were obtained as the first fraction at a boiling point of 114° to 117° C., and 78 g of a mixture consisting of 66% of 2-bromo-4-fluorotoluene, 24% of 3-bromo-4-fluorotoluene and 9% of dibromo-4-fluorotoluene were obtained as the second fraction at a boiling point of 175° to 185° C. Relative to the 4-fluorotoluene reacted, the yield of 2-bromo-4-fluorotoluene plus 3-bromo-4-fluorotoluene was 48% and that of 3-bromo-4-fluorotoluene was 11.4%.