poly(ethylene glycol) hexaethylene glycol 282.168 282.33064 3,6,9,12,15-pentaoxaheptadecane-1,17-diol Beilstein:1638281 C12H26O7 CAS:2615-15-8 CHEBI:44878 CHEBI:49792 CHEBI:49793 Gmelin:754022 HEXAETHYLENE GLYCOL Hexagol IIRDTKBZINWQAW-UHFFFAOYSA-N InChI=1S/C12H26O7/c13-1-3-15-5-7-17-9-11-19-12-10-18-8-6-16-4-2-14/h13-14H,1-12H2 OCCOCCOCCOCCOCCOCCO PDBeChem:P6G PEG-6 chebi_ontology hexaoxyethylene glycol