Iodine → 2-Bromo-4-fluorotoluene

Participants

Reaction Steps

A solution of 160 g of bromine in 60 ml of glacial acetic acid was added all at once 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 3 hours, the glacial acetic acid and unreacted 4-fluorotoluene were then distilled off in vacuo and a mixture consisting of 3-bromo-4-fluorotoluene (57%), 2-bromo-4-fluorotoluene (41.9%) and dibromo-4-fluorotoluene (1.1%) was subsequently distilled off under 20 mbars and between 65° C. and 85° C. 8 g of residue remained. The monobrominated isomers were separated by distillation on a column. 21.5 g of 2-bromo-4-fluorotoluene (boiling point: 176°-8° C. (normal pressure)) and 28.5 g of 3-bromo-4-fluorotoluene (boiling point 184°-5° C. (normal pressure)) were obtained.

Provenance & Evidence