M 1890 (OTTO) 4-Methoxy phenol, 99% Cas no 150-76-5 - used to inhibit the radical polymerization of monomers & also used in dermatology and organic chemistry. M 1890 (OTTO) 4-Methoxy phenol, 99% Cas no 150-76-5 - used as polymerization inhibitors. For example, in the radical polymerization of acryaltes and styrene monomers.