M 2125 (OTTO) Methyl Iodide, 99% Cas 74-88-4 - used in the preparation of Tetra Methyl Ammonium Hydroxide. Iodomethane is used in the preparation of Methyl Magnessium Iodide (Grignard reagent). M 2125 (OTTO) Methyl Iodide, 99% Cas 74-88-4 - used for alkylating carbon, oxygen, sulfur, nitrogen and phosphorus nucleophiles. For example, phenol reacts with methyl iodide to give anisole. In the Monsanto process, the in situ formed iodomethane reacts with carbon monoxide in the presence of a rhodium complex to give acetyl iodide, which on hydrolysis yields acetic acid.