Propofol EP Impurity J Catalogue B485430 CAS 1988-11-0 M.W 192.25 M.F C12H16O2 Specifications FAQs 2,6-Diisopropyl-1,4-benzoquinone; 2,6-diisopropylbenzoquinone; 2,6-diisopropylcyclohexa-2,5-diene-1,4-dione