| abstract |
A quaternary ammonium salt of formula (I): wherein X is a linking group; Y is O, NH or NR 1 wherein R 1 is H or an optionally substituted hydrocarbyl group; Q + is a moiety that includes a quaternary ammonium cation; A - is an anion; R 2 is an optionally substituted alkylene group; R 3 is hydrogen or an optionally substituted hydrocarbyl group; and n is 0 or a positive integer; provided that n is not 0 when R 3 is hydrogen. |