Catalyst and process for the production of isoolefins

The present invention relates to a method for preparing a catalyst which has formally 0.1 to 20% by weight alkali and / or alkaline earth metal oxide, 0.1 to 99% by mass of aluminum oxide and 0.1 to 99 mass% silicon dioxide, which is characterized in that it comprises the steps of treating an aluminosilicate with an aqueous alkali and / or alkaline earth metal salt under acidic conditions and calcining said treated with aqueous alkali and / or alkaline earth metal aluminosilicate, and a catalyst obtainable by this process, the alkali metal formal and / or alkaline earth metal oxide comprises alumina and silica, which is characterized in that the catalyst is formally a content of alkali metal and / or alkaline earth metal oxide of 0.5 to 20% by mass, a proportion of aluminum oxide 4-30% by mass and has a proportion of silicon dioxide of 60 to 95% by mass, and the use of this catalyst in a V out for the production of isoolefins with 4 to 6 carbon atoms by gas-phase catalytic decomposition of tertiary alcohols or alkyl-tert-alkyl ethers.