Structure, dynamics, and reactivity of an alkoxy intermediate formed from acetylene on zeolite catalysts: an in situ solid-state NMR study

Acetylene Absorption and Binding in a Nonporous Crystal Lattice

“…An occupancy study (Figure 2, that is, percentage occupancy versus equilibrium pressure) shows that the uptake of acetylene at standard temperature and pressure (STP) is approximately 2 % by weight. This value corresponds to 39 cm 3 g −1 and is comparable to, or exceeds the values obtained for carbon nanotubes and inorganic zeolites such as Zeolite 4 A 14. The seemingly nonporous crystals absorb 0.515 mol of acetylene per mol of host at 298 K and 1 atm pressure indicating complete filling of the available volume in the crystal structure (i.e.…”

Impact of in situ MAS NMR techniques to the understanding of the mechanisms of zeolite catalyzed reactions

“…The data obtained are summarized in Table 2. The experimental evidences were obtained on the formation of ethoxy, 122 vinyl alkoxy 119 and isopropoxy 10,12,36 species from the corresponding olefins at the very early stages of the reaction. Simple carbenium ions were not observed, even when cyclopentene and cyclohexene were used as starting reactants.…”

Physical Organic Chemistry of Solid Acids: Lessons from in Situ NMR and Theoretical Chemistry

“…15 A number of different alkoxyl species have been characterized on acidic zeolites including studies of the tert-butyl alkoxyl 20,21 and a species derived from acetylene. 22 In an early example of the application of theoretical approaches to reactions on solid acids, Kazansky predicted that ethylene would not protonate to make the ethyl cation, but instead a framework alkoxyl. 23 Similar species also form from the reactions of alkyl halides on metal-exchanged zeolites as demonstrated by the papers of Murray 24,25 and Bosa ´cek.…”