1,4,7,10,13,16-HEXAOXACYCLOOCTADECANE 1,4,7,10,13,16-Hexanoxacyclooctadecane 134316-24-8 168081-58-1 17455-13-9 18-Crown-6 5-19-12-00601 (Beilstein Handbook Reference) 63172-42-9 65154-22-5 66037-87-4 71210-94-1 71211-03-5 71245-01-7 71251-38-2 71251-39-3 71251-42-8 BRN 1619616 CCRIS 3587 EINECS 241-473-5 Ethylene oxide cyclic hexamer NSC 159836