1,5-NAPHTHALENEDISULFONIC ACID 1,5-Naphthylene disulfonic acid 4-11-00-00561 (Beilstein Handbook Reference) 46874-44-6 81-04-9 Armstrong's S acid Armstrong's acid BRN 0619838 EINECS 201-317-9 NSC 9588 Naphthalene-1,5-disulphonic acid