Patent ID: 7601871

Claim:
A method of purifying quaternary onium salts comprising the step of contacting a composition comprising an organic solvent-based onium salt solution, wherein said onium salt comprises one or more anions selected from the group consisting of BF4 − , [BF x (C y F 2y+1−z H z ) 4−x ] n − in which the ligands (C y F 2y+1−z H z ) may be identical or different, 1<x<3, 1≦y≦8 and 0≦z≦2y+1, PF 6 − , [PF x (C y F 2y+1−z H z ) 6−x ] − in which in which the ligands(C y F 2y+1−z H z ) may be identical or different, 1≦x≦5, 3≦y≦8 and 0≦z≦2y+1, CF 3 SO 3 − , SbF 6 − , N(SO 2 CF 3 ) 2 − , C 4 H 3 O 4 − , and ClO 4 − and a first concentration of halide ionic impurities with an ion exchange material to produce a composition comprising a quaternary onium salt and a second concentration of halide ionic impurities, wherein said second concentration of halide ionic impurities is less than said first concentration of halide ionic impurities.