FRINK Linked Data Fragments server

Matches in SemOpenAlex for { <https://semopenalex.org/work/W2945227364> ?p ?o ?g. }

• W2945227364 endingPage "6168" @default.
• W2945227364 startingPage "6146" @default.
• W2945227364 abstract "Measurements of turnover rates of gas-phase bimolecular ethanol dehydration to diethyl ether (404–438 K) on a suite of hydrophobic and hydrophilic Sn-zeolites (Sn-Beta, Sn-BEC, Sn-MFI) of varying Sn content, together with quantitative titration of active Sn sites by pyridine during catalysis, identify two types of Sn sites with reactivity differing by more than an order of magnitude (>20×). Apparent activation entropies to form bimolecular dehydration transition states from predominantly ethanol monomer-covered sites are less negative (ΔΔSapp⧧ = 48 ± 22 J mol–1 K–1) at the more reactive subset of Sn sites, which are present in amounts equivalent to 17–26% of the Sn sites quantified by the peak centered at 2308 cm–1 in CD3CN IR spectra (Sn2308) but not correlated with that at 2316 cm–1 (Sn2316). Synthetic and postsynthetic treatments to prepare Sn-zeolites containing Sn sites hosted within diverse local coordination environments suggest that Sn2316 sites are not associated with Sn bound to residual fluoride anions or Sn sited at external crystallite surfaces, amorphous domains, or among the diverse T-site locations contained within CHA, MFI, BEC, and STT frameworks. Treating Sn-Beta in HF or NH4F solutions, which dissolve zeolitic domains preferentially at defect grain boundaries, decreased the number of Sn2316 sites but not Sn2308 sites. These data indicate that Sn2316 sites are preferentially located at stacking faults in zeolite Beta, which provide tetrahedral coordination environments for Sn in defect-open configurations ((HO)–Sn–(OSi≡)3) with proximal Si–OH groups that do not permit condensation to tetrahedral closed configurations (Sn–(OSi≡)4). A computational model was developed for stacking fault defect-open Sn sites, which predict apparent activation free energies for bimolecular ethanol dehydration that are 65–74 kJ mol–1 higher (at 404 K) than those at framework-closed Sn sites that are capable of stabilizing transition states via Sn site opening and closing as part of the catalytic cycle, consistent with the lower experimentally measured ethanol dehydration reactivity for Sn2316 sites. In contrast, defect-open sites possess Si–OH groups that preferentially stabilize hydride shift transition states involved in glucose–fructose isomerization catalytic cycles. These findings highlight the ability of a given zeolite framework to confer structural diversity to nominally site-isolated Lewis acid centers, thus generating configurations with distinct reactivity for different chemical transformations." @default.
• W2945227364 created "2019-05-29" @default.
• W2945227364 creator A5014967076 @default.
• W2945227364 creator A5026571515 @default.
• W2945227364 creator A5041107836 @default.
• W2945227364 creator A5062626839 @default.
• W2945227364 creator A5072511676 @default.
• W2945227364 date "2019-05-23" @default.
• W2945227364 modified "2023-10-17" @default.
• W2945227364 title "Distinct Catalytic Reactivity of Sn Substituted in Framework Locations and at Defect Grain Boundaries in Sn-Zeolites" @default.
• W2945227364 cites W1967622559 @default.
• W2945227364 cites W1970127494 @default.
• W2945227364 cites W1973303143 @default.
• W2945227364 cites W1978075309 @default.
• W2945227364 cites W1979544533 @default.
• W2945227364 cites W1981518452 @default.
• W2945227364 cites W1982483551 @default.
• W2945227364 cites W1982685255 @default.
• W2945227364 cites W1997743588 @default.
• W2945227364 cites W2001825008 @default.
• W2945227364 cites W2002995405 @default.
• W2945227364 cites W2007395042 @default.
• W2945227364 cites W2020720383 @default.
• W2945227364 cites W2021747105 @default.
• W2945227364 cites W2023053035 @default.
• W2945227364 cites W2023820214 @default.
• W2945227364 cites W2028368369 @default.
• W2945227364 cites W2029441652 @default.
• W2945227364 cites W2031430816 @default.
• W2945227364 cites W2033527720 @default.
• W2945227364 cites W2034689869 @default.
• W2945227364 cites W2038971223 @default.
• W2945227364 cites W2039596389 @default.
• W2945227364 cites W2040786465 @default.
• W2945227364 cites W2044591029 @default.
• W2945227364 cites W2045661998 @default.
• W2945227364 cites W2046158004 @default.
• W2945227364 cites W2049410499 @default.
• W2945227364 cites W2050102116 @default.
• W2945227364 cites W2059363217 @default.
• W2945227364 cites W2059786240 @default.
• W2945227364 cites W2065077278 @default.
• W2945227364 cites W2077279509 @default.
• W2945227364 cites W2083222334 @default.
• W2945227364 cites W2084851675 @default.
• W2945227364 cites W2085607059 @default.
• W2945227364 cites W2086256893 @default.
• W2945227364 cites W2087698390 @default.
• W2945227364 cites W2099703449 @default.
• W2945227364 cites W2109715305 @default.
• W2945227364 cites W2112270990 @default.
• W2945227364 cites W2116629761 @default.
• W2945227364 cites W2121379638 @default.
• W2945227364 cites W2122427541 @default.
• W2945227364 cites W2132723749 @default.
• W2945227364 cites W2133705601 @default.
• W2945227364 cites W2136260455 @default.
• W2945227364 cites W2139628787 @default.
• W2945227364 cites W2165046085 @default.
• W2945227364 cites W2168421978 @default.
• W2945227364 cites W2237532994 @default.
• W2945227364 cites W2269575903 @default.
• W2945227364 cites W2289814764 @default.
• W2945227364 cites W2296974377 @default.
• W2945227364 cites W2307947977 @default.
• W2945227364 cites W2309746662 @default.
• W2945227364 cites W2317566433 @default.
• W2945227364 cites W2320116012 @default.
• W2945227364 cites W2321497013 @default.
• W2945227364 cites W2328928309 @default.
• W2945227364 cites W2331212077 @default.
• W2945227364 cites W2333046275 @default.
• W2945227364 cites W2393949105 @default.
• W2945227364 cites W2474398724 @default.
• W2945227364 cites W2507736161 @default.
• W2945227364 cites W2522603125 @default.
• W2945227364 cites W2528436827 @default.
• W2945227364 cites W2529665182 @default.
• W2945227364 cites W2542707118 @default.
• W2945227364 cites W2556187544 @default.
• W2945227364 cites W2589684704 @default.
• W2945227364 cites W2600557025 @default.
• W2945227364 cites W2605015624 @default.
• W2945227364 cites W2615867191 @default.
• W2945227364 cites W2736999751 @default.
• W2945227364 cites W2746410433 @default.
• W2945227364 cites W2754411384 @default.
• W2945227364 cites W2788875611 @default.
• W2945227364 cites W2789780054 @default.
• W2945227364 cites W2790838315 @default.
• W2945227364 cites W2801391910 @default.
• W2945227364 cites W2807379693 @default.
• W2945227364 cites W2876990419 @default.
• W2945227364 cites W2883377531 @default.
• W2945227364 cites W2884667846 @default.
• W2945227364 cites W2888827214 @default.
• W2945227364 cites W2890466040 @default.
• W2945227364 cites W2893252964 @default.

• next