Propofol EP Impurity P Catalogue B485436 CAS 2095678-97-8 M.W 264.36 M.F C16H24O3 Specifications FAQs 1-methylethyl 4-hydroxy-3,5-bis(1-methylethyl)benzoate; isopropyl 4-hydroxy-3,5-diisopropylbenzoate