ABSTRACT
Synthesis of methyl-tertiary-butyl ether (MTBE) by the electrophilic addition of methanol to isobutene as well as by etherification of methanol-t-butanol mixture needs catalysts exhibiting strong protonic acidity. In industry, MTBE is produced in the liquid phase using ionexchange resins such as Amberlyst-15 at temperatures above 373 K. At these conditions sulfonated resins are not stable enough and gradually lose sulfuric acid, thus decreasing activity and creating the possibility of environmental damage. For this reason the search for more convenient catalysts has been undertaken in many laboratories. Various mineral substances have been used: zeolites, silica-alumina, acidtreated clays, and also heteropolyacids. The latter, among the strongest mineral acids, are the subject of the present chapter.
