Several companies are developing the manufacture and use of dimethyl ether, CH3OCH3, as an efficient and clean alternative to diesel fuel [Chemical and Engineering News, 1995 (May 29), 37-39]. Much of this interest in dimethyl ether and other related compounds is focused on minimizing C--C bonds in fuels in order to limit formation of polycyclic aromatic hydrocarbons; see "A Word About . . . Polycyclic Aromatic Hydrocarbons and Cancer" on page 136. Show how dimethyl ether could be synthesized from methanol.