| abstract |
A compound of general formula (I) or (II), wherein R n and R m independently represent a C 3 -C 27 aliphatic group, R 1 to R 4 , which may be the same or different at each occurrence, represent hydrogen or a C 1 -C 8 alkyl group, X 1 and X 2 , which may be the same or different at each occurrence, represent a linear or branched divalent hydrocarbon radical with 1 to 24 carbon atoms which can be optionally substituted and/or interrupted by one or more heteroatoms or heteroatom containing groups, and R 5 and R 6 , which may be the same or different at each occurrence, represent a group selected from —O − , -Alk-CH(OH)—CH 2 —SO 3 — and -Alk-CO 2 — wherein Alk represents an alkylene group. |