To isolate the subject compound as a highly pure solid (powder) in a good yield by filtering the solution of a specific tris(fluorinated aryl)boron containing two kinds of specific impurities, cooling the filtrate, and subsequently again filtering the cooled filtrate.
This method for isolating a tris(fluorinated aryl)boron comprises filtering a solution containing (A) the tris(fluorinated aryl)boron of the formula (R1-R5 are each H, F, a hydrocarbon group, an alkoxy, wherein one or more of R1-R5 are each F), (B) a magnesium halide such as a compound of the formula: MgXaXb (Xa is Cl, Br, I; Xb is F, Xa) and (C) an etheric solvent (e.g. dimethyl ether) as impurities preferably at 0-200°C, more preferably at 30-150°C, to remove the component B, cooling the first filtrate preferably at ≤150°C, more preferably at -50 to 80°C, to deposit the component A substantially not containing the component C as crystals, and, if necessary, further cooling and filtering the second filtrate.
MITSUI HITOSHI
UENO TSUNEMASA
YAMAMOTO NAOKO
