Younghee Ko

Novel layered sulfides of tin: synthesis, structural characterization and ion exchange properties of TMA-SnS-1, Sn3S7·(NMe4)2·H2O

Sn3S7·(NMe4)2·H2O has been shown to consist of the framework of composition [Sn3S7]2– with the two exchangeable [NMe4]+ ions occupying cavities in the structure; these molecules can be exchanged with a variety of alkali, alkali earth and transition metal cations.

Vapor phase Beckmann rearrangement of cyclohexanone oxime over metal pillared ilerite

Abstract The vapor phase Beckmann rearrangement of cyclohexanone oxime to e-caprolactam has been studied using various metal pillared ilerites (M-ilerite) as catalysts. Ta- and Nb-ilerite exhibited high catalytic activities for the vapor phase Beckmann rearrangement. The oxime conversion over Ta-ilerite reached up to 98.9% with the lactam selectivity of 96.7% at 350°C. FT-IR and NH 3 -TPD results revealed that the excellent catalytic performance of Ta- and Nb-ilerite should be ascribed to a large number of hydroxyl groups of the catalyst and their relatively weak acidity.

A novel antimony sulfide templated by ethylenediammonium

The structure of ethylenediammonium antimony sulfide, C 2 H 10 N 2 2+ .Sb 8 S 13 2- , is characterized by double chains of corner-linked SbS 3 pyramids. These chains contain openings formed by 16-membered rings, consisting of alternating Sb and S atoms, and interlock to form sheets in (001)

Trimethylammonium tin sulfide

The structure of trimethylammonium tin sulfide-water (1/0.72), [(CH 3 ) 3 NH] 2 [Sn 3 Sr].0.72H 2 O, consists of sheets with 24-membered ring openings containing alternating Sn and S atoms. Organic molecules resulting from the breakdown of the starting tetramethylammonium template reside between these sheets, which are stacked parallel to (001)

Novel layered sulfides of tin: synthesis and structural characterization of Cs4Sn5S12·2H2O and Sn5S12(N2C4H11)2(N4C10H24)

Framework compositions [Sn5S12]4– have been synthesized hydrothermally in the presence of triethylenediamine (Dabco) and caesium, respectively; the cations are accommodated between the sheets with orientation relationships suggestive of a templating mechanism and their crystal structures have been determined.

Synthesis of Co-silicalite-1 from a layered silicate

Co-Silicalite-1 (Co2.3Si93.7O192) was synthesized from Co2+ ion exchanged magadiite. The characteristics of Co-Silicalite-1 were investigated by using X-ray powder diffraction, IR spectroscopy, surface area measurement, NH3 temperature programmed desorption, and electron microprobe analysis. The measurements indicate that Co2+ ions replace Si4+ ions in the Silicalite-1 framework. The orthorhombic framework structure of calcined Co-Silicalite-1 has been determined.

Synthesis and characterization of Ta-pillared ilerite

Abstract A new porous material, Ta-pillared ilerite is derived by pillaring tantalum oxide into silicic acid of ilerite. The new material was characterized through solid state 29 Si NMR, IR, X-ray, TGA, UV-VIS, TPD and BET measurements. Upon pillaring of tantalum oxide, the basal spacing of ilerite is expanded to 37 Ǻ, and pillared structure of the ilerite is preserved even after calcination at 700°C. The BET surface areas of the Ta-pillared ilerite after complete elimination of the surfactant are ranged between 378 m 2 /g and 400 m 2 /g. From the NH 3 -TPD profile of Ta-pillared ilerite, it is showfl that the new material contains large number of acid sites of intermediate acidity.

23-P-18 - Vapor phase Beckmann rearrangement of cyclohexanone oxime over tantalum pillared magadiite

Publisher Summary This chapter discusses the vapor-phase Beckmann rearrangement of cyclohexanone oxime over tantalum-pillared magadiite. Vapor-phase Beckmann rearrangement of cyclohexanone oxime to ɛ-caprolactam has been carried out using tantalum-pillared magadiites (Ta-magadiites) with different surface areas as catalysts. The Ta-magadiite catalysts of relatively large surface areas show high catalytic activities because of a large number of active sites. For the Ta-magadiite catalyst of the largest surface area, the oxime conversion reached 99.1% with 97.5% of lactam selectivity. Fourier transform infrared (FT-IR) and ammonia (NH 3 )-temperature-programmed desorption (TPD) results demonstrate that the new hydroxyl groups and a large amount of acidic sites generated by Ta pillaring into the magadiite interlayer are responsible for the high catalytic performance of Ta-magadiite catalyst.

A one-dimensional germanium sulfide polymer akin to the ionosilicates: synthesis and structural characterization of DPA-GS-8, Ge4S9(C3H7)2NH2(C3H7)NH2(C2H5)

Ge4S9(C3H7)2NH2(C3H7)NH2(C2H5) consists of chains of corner-linked adamantane units with a composition of [Ge4S9]2– which are separated by two dipropylammonium (DPA) cations; the first reported chain-like structure of [Ge4S9]2–.

Vapor phase Beckmann rearrangement of cyclohexanone oxime over a novel tantalum pillared-ilerite

The vapor phase Beckmann rearrangement of cyclohexanone oxime has been studied using a novel tantalum pillared-ilerite as catalyst: the cyclohexanone oxime conversion rate reaches 97.1% and the selectivity for e-caprolactam is up to 89.1% at 350 °C.