Description CAS#: 109-99-9 | Formula: C4H8O | Specifications: Assay 99.8 % - Min, Color (APHA) 10 Max, Peroxides (%) 0.015 % Max, Residue after evaporation 0.03 % Max, Titrable acid 0.001 meq/g Max, Water (by KF) 0.035 % Max