A process for reacting a first component with itself or a second component to produce a third component in which a first material comprising a first component or said first component and a second component is fed to divided wall column having a catalytic distillation structure in at least one of the separate vertical sections of the divided wall column where concurrently: (1) a first component alone or with a second component is contacted with a catalytic distillation structure in a distillation reaction zone thereby catalytically reacting at least a portion of the first component with itself or with the second component to form a product and (2) a first mixture comprising the first component and the product or the first component, the second component and the product; and withdrawing the product from the distillation column reactor; while within the column concurrently with the catalytic reaction and fractionation a second mixture is fractionated, which contains the first component and the product or first and second components (if a second component is present) and the product in a parallel and separate distillation non reaction zone to fractionate the product and withdrawing the product from said distillation non reaction zone. For example, tertiary amyl methyl ether may be prepared by reacting methanol with isoamylene in a C₅ stream utilizing a distillation column reactor wherein the distillation column reactor comprises one side of a divided wall column. On one side the product, tertiary amyl methyl ether, is separated from the unreacted methanol and C₅'s and on the other side the remaining isoamylenes are reacted with methanol and a separation of the tertiary amyl methyl ether and C₅'s from the methanol/C₅ azeotrope is effected.