Ação promotora do zinco em catalisadores de síntese do estireno

Abstract

Recebido em 12/5/03; aceito em 2/9/03 THE PROMOTER ACTION OF ZINC ON CATALYTS FOR STYRENE SYNTHESIS. Ethylbenzene dehydrogenation in the presence of steam is the main commercial route to produce styrene. The industrial catalyst is chromium and potassium-doped hematite, which easily deactivates with time due to potassium loss. In order to find non-toxic and potassium free catalysts, the promoter action of zinc on hematite was studied in this work. It was found that zinc acts as structural promoter by stabilizing the Fe 3+ species (active phase) as maghemite. Although it decreases the specific surface area, it increases four times the catalytic activity as compared to hematite.