abstract |
A sulfonic acid or carboxylic acid containing a carbonyl group, or a salt thereof represented by the following formula:n nR 1 —C(═O)—(CR 2 2 ) n —(OR 3 ) p —(CR 4 2 ) q -L-An nwherein R 1 , R 2 , R 3 , R 4 , n, p, q, A and L are as defined herein. |