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Solid-state reactions of In 2 O 3 /H-mordenite and In 0 /H-mordenite mixtures (Al/In ) 3) were studied using an atmospheric flow-through microreactor, diffuse reflectance Fourier-transform spectroscopy (DRIFTS), and X-ray powder diffractometry (XRD). The indium(III)oxide/H-mordenite mixture was heated in a flow of 2% H 2 /N 2 gas mixture or pure N 2 to 873 and 973 K, respectively. The indium(0)/H-mordenite mixture was heated in a dry and wet N 2 stream to 673-973 K. The reactions were monitored by analyzing the effluent gas, using mass spectroscopy (MS). The protons of H-mordenite were exchanged for In + cations, indicating that In 3+ was reduced and In 0 was oxidized in the exchange processes. In the process of reductive solid-state ion exchange (RSSIE), the indium was reduced by H 2 . In the oxidative solid-state ion exchange (OSSIE) process, the indium was oxidized by H 2 O. Results substantiate that the ion exchange proceeds through a volatile InOH intermediate. Formation of InOH and its rapid transport within the zeolite crystals requires the presence of water vapor. The In + in the zeolite lattice can be oxidized by O 2 or H 2 O to indium oxycations, most probably to InO + , while the obtained oxycations can be reduced in hydrogen back to In + .

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Shaping zeolites into useful forms is very important for technical applications in areas such as catalysis, separation, and sensing. Normally it is difficult to form zeolites into appropriate shapes without mixing them with binders. Here, a method is presented for transforming preformed layered silicates into silicalite zeolites (e.g. see Figure). magnified image

The hydroconversion mechanism of γ-valerolactone (GVL) was studied over a Co/SiO 2 and a Pt/aluminosilicate catalyst. The reaction was carried out at 250 °C, 30 bar, and WHSV= 1 g GVL •g cat. -1 •h -1 . The Co/SiO 2 catalyst had moderate hydrogenation activity and Lewis acidity, whereas the Pt/aluminosilicate catalyst had high hydrogenation activity and Brønsted acidity. Diffuse Reflectance Fourier Transform Spectroscopic (DRIFTS) results suggested that the GVL ring was bounded more strongly to the stronger acid Pt/aluminosilicate that to the weaker acid Co/silica catalyst. The Pt/aluminosilicate catalyst was substantiated to open the GVL ring in a protonation/deprotonation process giving pentenoic acid (PE) intermediate and pentanoic acid (PA) as main final product. Over Co/SiO 2 catalyst 2-methyl-tetrahydrofuran (2-MTHF) and pentanol were the major products of GVL conversion. It was substantiated that latter transformation proceeded in consecutive hydrogenation and dehydration steps via 2hydroxy-5-methyl-tetrahydrofuran and 1,4-pentanediol (1,4-PD) intermediates. The oxygen atoms of GVL were shown to establish H-bonds with the silanol groups of the Co/SiO 2 catalyst. The  CO frequency of the adsorbed GVL depends on the adsorption interaction of the GVL and the silica surface. Three distinct  CO bands were distinguished by DRIFTS. Quantum chemical calculations gave the structures of the three adsorbed GVL species. Operando DRIFTS examination of the catalytic reaction suggested that in the structure that was activated for hydrogenation/hydrogenolysis both the ring and the carbonyl oxygen were bound to silanol groups.