2-Hydroxyethanesulfonic acid, compd. with alpha,alpha-dimethyl-4-(1,1,2,2-tetrafluoro-2-phenylethyl)benzenemethanamine (1:1) 40396-83-6 MK 251 MK-251 alpha,alpha-Dimethyl-4-(alpha,alpha,beta,beta-tetrafluorophenethyl)benzylamine