| abstract |
A bis(1,1,3,3-tetramethylbutyl)phosphinic acid compound represented by the formula (1) and an extracting agent using the same for separating Co from an aged electroless Ni plating solution. A di(1,1,3,3-tetramethylbutyl)phosphine is produced by carrying out a reaction between phosphine and trimethylpentene in the presence of an organic solvent and a catalyst, then said phosphine is reacted with an oxidizing agent or sulfur to obtain the compound (1): <IMAGE> (1) (wherein X1 and X2 are O or S). |