Organic reactions catalyzed over solid acids

Layered zeolitic materials: an approach to designing versatile functional solids

“…95,98,110 Following this line and considering the high surface area, the acid site's accessibility and the hydrothermal stability of ITQ-2 zeolites, elevated yields were obtained for skeletal isomerization and dehydroisomerization of 1-butene and n-butene to isobutene or alkylation of toluene with methanol and biphenyl with propylene, avoiding in both cases the extensive coke formation. 111,112,113 The physico-chemical and textural properties linked to highly accessible delaminated ITQ-2 zeolites were also positive to carry out reactive processes with industrial application such as the synthesis of diaminophenylmethane (DADPM), i. e. the polyamine precursor in the production of methylene diphenylene diisocyanate (MDI) for polyurethanes generation. 114,115,116 Moreover, the open structure of exfoliated materials was used for methanol to olefins conversion (MTO) and dehydrogenation of propane to propylene in presence of CO 2 over ITQ-2 supported gallium oxide.…”

Acidic sites in beta zeolites in dependence of the preparation methods

“…Two important factors are well known to contribute to the activity of the zeolite catalysts-their aperture and acidity. For a given zeolite structure, it is generally observed that optimum in catalytic activity is reached at a high aluminium content, since a strong correlation has been established between the latter and the zeolite acidity [1][2][3]. Regarding beta zeolite, this statement is not entirely perfect, because of its peculiar pore system which is disordered and is build from channels instead of cages [4,5].…”

Soybean Oil De-Acidification as a First Step Towards Biodiesel Production

“…Only largepore zeolites have been used in FFA esterification to avoid limitation to the mass transfer of both reactants and products inside the catalyst's pores. Their use along with high operating temperatures may lead to the formation of undesired by-products (Corma and Garcia, 1997). Silica molecular sieves with amorphous pore walls, as MCM-41, are not sufficiently acid to catalyze the esterification process.…”