Patent ID: 8641816

Claim:
A compound of formula I: wherein R 1 is C 1 -C 12 alkyl; R 2 is C 1 -C 23 alkyl; R 3 is SO 3 − M + , a tertiary amine, a quaternary ammonium, a tertiary phosphine, a quaternary phosphonium, alkenyloxy, alkoxy, poly(alkoxy), alkynyloxy, aryloxy, cycloalkenyloxy, cycloalkoxy, halo, haloalkyloxy, aminoalkyloxy, (trialkylammonio)alkyloxy, hydroxyalkyl-amino, aryloxy-alkoxy, heterocycloalkyl, or thioether; M + is H + or a monovalent or divalent cation, wherein the total number of carbon atoms in R 1 , R 2 and the carbon to which they are attached is 4 to 22, and wherein the alkoxy group of R 3 is ethoxy, propoxy, isopropoxy, 1-butoxy, 2-butoxy, isobutoxy, tert-butoxy, pentoxy, 2-methylbutoxy, 1,1-dimethylpropoxy, hexoxy, heptoxy, octoxy, nonoxy, or decoxy.