A process for preparing boron trichloride.

摘要

In the prodn. of BCl3 by chlorinating borate esters (I), a reactor is chaged with Cl2 and (I) in 5.5-7.5:1 (5.75-6.75:1) molar ratio and allowed to react in the presence of free radical initiator (II) at 20-100 (40-90, esp. 60-80) degrees C with simultaneous removal of the reaction prods. in the gaseous state. Reaction is carried out continuously and the liquid mixt. is also removed from the reactor and distilled, the distillate being returned to the reactor. The amt. of liq. removed is 4-20 (6-15, esp. 8-12) vol.% of the total per hour. The B content of the recycled distillate is adjusted by adding (I). Reaction is carried out at 1.01-2.43 (1.01-2.13) bar. An inert liquid organic solvent (CCl4) can be added, this being removed with the gaseous prod., condensed and recycled. BCl3 has many industrial uses, e.g. as intermediates for other B cpds. (diboranes, refractory metal borides TiB2), as refrigerant and as catalyst for Grignard reactions. The amt. of COCl2 formed as by-prod. is reduced considerably.