51337-71-4 Clofop Isobutyl 2-[4-(4-chlorophenoxy)phenoxy]propionate NSC321036 Propanoic acid, 2-[4-(4-chlorophenoxy)phenoxy]-, 2-methylpropyl ester Propionic acid, 2-[4-(4'-chlorophenoxy)phenoxy]-, isobutyl ester