1,5-Dioxaspiro(5.5)undecane, 2-methyl- 2-Methyl-1,5-dioxaspiro(5.5)undecane 6413-26-9 94720-16-8 AI3-22544 Cyclohexanone 1,3-butylene glycol ketal EINECS 229-115-6 NSC 46270