Process for the bromination in the alpha-position of possibly substituted fluortoluenes and mixtures of possibly substituted fluortoluenes having a different number of bromine atoms in the alpha-position

摘要

Possibly substituted fluorotoluenes are brominated in the alpha -position using 0.5 to 3.2 mol of bromine per mol of fluorotoluene at a temperature of 130 to 250 DEG C and with continuous removal of the hydrogen bromide formed at the same time. The reaction can be carried out in the presence of a solvent or with photochemical or free-radical initiation. By using various amounts of bromine within the range indicated, mixtures can be obtained which contain 90 to 93 % by weight of the corresponding fluorobenzal bromide, 3 to 4 % by weight of the corresponding fluorobenzyl bromide and 4 to 6 % by weight of the corresponding fluorobenzotribromide, or mixtures which contain 15 to 95 % by weight of the corresponding fluorobenzotribromide and 5 to 85 % by weight of the corresponding fluorobenzal bromide or mixtures which contain 40 to 85 % by weight of the corresponding fluorobenzal bromide and 15 to 60 % by weight of the corresponding fluorobenzyl bromide, or mixtures which contain 95 to 100 % by weight of the corresponding fluorobenzal bromide and 0 to 5 % by weight of the corresponding fluorobenzyl bromide.