1,4,7,10-TETRAOXACYCLODODECANE 12-Crown-4 168081-54-7 294-93-9 5-19-11-00334 (Beilstein Handbook Reference) 64491-37-8 BRN 1363064 CCRIS 157 EINECS 206-036-5 EOCT Ethylene oxide cyclic tetramer