The present invention provides a method for preparing an antiulcer agent, 2-benzimidazoles, such as Omeprazole, Lansoprazole, Pantoprazole and Rabeprazole, which includes oxidizing an intermediate having a linkage of methylthio group to methylsulfinyl \u2014) in the presence of an oxidation catalyst of an alkali metal salt of tungstate at a temperature of 10-50\xb0 C. An annular receiving groove is recessed from a bottom face of the base. The manifold system is constructed so that after it has been installed, it may be converted for use in other applications such as between compressed gas cylinders and portable bulk liquefied gas.