Iodine → 2-Bromo-4-fluorotoluene

Participants

Reaction Steps

A solution of 160 g of bromine in 60 ml of glacial acetic acid was added, in the course of 3 hours, to a solution of 110 g of 4-fluorotoluene in 40 ml of glacial acetic acid, to which 1.1 g of iron powder and 1.1 g of iodine had been added. The initially exothermic reaction was kept at 25° C. to 27° C., first by cooling with water and then with warm water. The mixture was subsequently stirred at the above temperature for 8 hours, the glacial acetic acid and unreacted 4-fluorotoluene were then distilled off under normal pressure up to a temperature of 120° C. and a mixture consisting of 3-bromo-4-fluorotoluene (62%), 2-bromo-4-fluorotoluene (32%) and dibromo-4-fluorotoluene (5%) was subsequently distilled off under 20 mbars and between 65° C. and 85° C. 34 g of residue remained. The monobrominated isomers were separated by distillation on a column. 12.7 g of 2-bromo-4-fluorotoluene (boiling point: 176°-8° C. (normal pressure), nD20 : 1.5260) and 24.5 g of 3-bromo-4-fluorotoluene (boiling point: 184°-5° C., (normal pressure), nD20 : 1.5303) were obtained.

Provenance & Evidence