1,1,1-Trifluoro-2-propanone 1,1,1-Trifluoroacetone 2-Propanone, 1,1,1-trifluoro- 3,3,3-Trifluoroacetone 421-50-1 Methyl trifluoromethyl ketone NSC66412 Trifluoromethyl methyl ketone