The present disclosure relates to the field of special electronic gases, in particular to a method for purifying electronic-grade boron trichloride. The method includes the following steps: (S.1), filling an adsorption composition into adsorbers; (S.2), vacuumizing the adsorbers to remove air from the adsorbers, and then introducing a high-purity boron trichloride gas; and (S.3), introducing a boron trichloride feed gas into the adsorbers, such that the boron trichloride feed gas is in contact with the adsorption composition, and collecting a gas flowing out of the adsorbers to obtain an electronic-grade boron trichloride gas. According to the present disclosure, coordination formed between hydrogen chloride impurities and boron trichloride can be eliminated effectively, thereby improving adsorption and purification effects of the boron trichloride. Meanwhile, the adsorption composition in the present disclosure has an excellent adsorption effect on an impurity gas, and a concentration of the impurity gas in the boron trichloride obtained after simple adsorption treatment can be decreased to a ppb (part per billion) level.

The present invention provides a method for separation and recovery of boron trifluoride and complexes thereof in an olefin polymerization reaction. The method for separation and recovery of boron trifluoride and complexes thereof in an olefin polymerization reaction, comprising: 1) subjecting a mixture obtained after an olefin polymerization reaction to flash distillation separation to separate part of gaseous boron trifluoride; 2) subjecting the liquid phase obtained from the flash distillation separation to membrane separation to obtain complexes of boron trifluoride and a crude product of the olefin polymerization reaction; and 3) subjecting the crude product of the olefin polymerization reaction obtained in step 2) to gas stripping separation to separate the remaining gaseous boron trifluoride, so as to obtain a pure product of the olefin polymerization reaction The present invention designs a matching process based on the polymorphic characteristics of boron trifluoride and complexes thereof to achieve efficient separation of boron trifluoride and complexes thereof from polymerization intermediates.