Incorporation of 2-Arylhexa-1,5-diene into Pentasil Zeolite:  A Distorted 1-Arylcyclohexane-1,4-diyl Radical Cation at Room Temperature

2005 ◽  
Vol 109 (7) ◽  
pp. 2504-2511 ◽  
Author(s):  
Hiroshi Ikeda ◽  
Tomonori Minegishi ◽  
Tsutomu Miyashi ◽  
Prasad S. Lakkaraju ◽  
Ronald R. Sauers ◽  
...  
Keyword(s):  
Radical Cation ◽  
Room Temperature ◽  
Zeolite A ◽  
Pentasil Zeolite

scholarly journals Parameters Expediting the Thermal Conversion of Ba-Exchanged Zeolite A to Monoclinic Celsian

2010 ◽  
Vol 2010 ◽  
pp. 1-8 ◽  
Author(s):  
A. Marocco ◽  
M. Pansini ◽  
G. Dell'Agli ◽  
S. Esposito
Keyword(s):  
Phase Transition ◽  
Amorphous Phase ◽  
Room Temperature ◽  
Thermal Conversion ◽  
Zeolite A ◽  
Thermal Transformations ◽  
Final Phase ◽  
Temperature Range ◽  
Thermally Treated

Four samples of Ba-exchanged zeolite A, bearing small residual amounts of Na (0.27, 0.43, 0.58, and 0.74 meq/g), were thermally treated in the temperature range 200–1500∘C for times up to 28 hours. The same samples were pressed at 30 and 60 MPa to form cylindrical pellets which were thermally treated at 1300∘C for 5 hours. All materials were characterized by room temperature XRD. The sequence of thermal transformations that Ba-exchanged zeolite A undergoes (zeolite → amorphous phase → hexacelsian → monoclinic celsian) and the strong mineralizing action developed by Na are confirmed. Pressing the Ba-exchanged zeolite A powder-like samples to obtain cylindrical pellets is found to expedite the sluggish final phase transition hexacelsian → monoclinic celsian. The optimum residual Na content of Ba-exchanged zeolite A for transformation into monoclinic celsian is assessed to be between 0.27 and 0.43 meq/g.

Elektrochemische Synthesen, XIV [1] Radikalkation-Salze des Naphthalins / Electrochemical Syntheses, XIV [1]. Radical Cation Salts of Naphthalene

1978 ◽  
Vol 33 (5) ◽  
pp. 498-506 ◽  
Author(s):  
Heinz P. Fritz ◽  
Helmut Gebauer ◽  
Peter Friedrich ◽  
Peter Ecker ◽  
Reinhold Artes ◽  
...  
Keyword(s):  
Radical Cation ◽  
Low Temperatures ◽  
Room Temperature ◽  
Specific Conductivity ◽  
Columnar Structure ◽  
Screw Axis ◽  
Radical Cation Salts ◽  
Difference Fourier ◽  
Pure Hydrocarbon

Abstract By anodic oxidation of naphthalene in H2CCl2/O.O2m Bu4NPF6 at -45 °C dark red-violet crystals of (C10H8)2PF6 can be obtained by electrocrystallisation. They are stable at low temperatures, however, decompose on warming. In solution and in the polycrystalline state these radical cation salts show only narrow e.p.r. signals without h.f.s. The specific conductivity of a polycrystalline pellet at room temperature was determined to be 0.12 ±0.046 Ohm-1 cm-1 . The structure determination of (C10H8)2PF6 yielded the tetragonal space group P42/n, Z = 2, a = b = 1156(2), c = 640(1) pm. Patterson synthesis and difference Fourier analyses showed the compound to have a columnar stacking of C10H8 units the long molecular axes of which are twisted alternately by 90° around a screw axis in c-direction, and the molecular planes of which are 320 pm apart. The PF6-ions have four nearest C10H8 neighbours lying in pairs in parallel planes 63 pm above and below that plane of PF6- perpendicular to the c-axis and containing a PF4 group. This is the first established case for a columnar structure of a pure hydrocarbon radical cation. (C10H8)2AsF6 is isomorphous.

Mechanism of Zeolite A Nanocrystal Growth from Colloids at Room Temperature

Science ◽  
1999 ◽  
Vol 283 (5404) ◽  
pp. 958-960 ◽  
Author(s):  
S. Mintova ◽  
N. H. Olson ◽  
V. Valtchev ◽  
T. Bein
Keyword(s):  
Room Temperature ◽  
Zeolite A ◽  
Nanocrystal Growth

Non Conventional Synthesis of Monoclinic Celsian from Ba-Exchanged Zeolite A: Study of the Effect of Residual Na and Forming Pressure

2006 ◽  
Vol 45 ◽  
pp. 963-968 ◽  
Author(s):  
C. Ferone ◽  
M. Pansini ◽  
Fernandanora Andreola ◽  
Luisa Barbieri ◽  
Cristina Siligardi ◽  
...  
Keyword(s):  
Phase Transition ◽  
Amorphous Phase ◽  
Room Temperature ◽  
Zeolite A ◽  
Thermal Transformations ◽  
Final Phase ◽  
Temperature Range ◽  
Thermally Treated

Four samples of Ba-exchanged zeolite A, bearing 0.27, 0.43, 0.58 and 0.74 meq/g Na residual amounts, were thermally treated in the temperature range 200-1500 °C for times up to 28 hours. The same samples were pressed at 30 and 60 MPa to manufacture cylindrical pellets, which were thermally treated at 1300 °C for 5 hours. Thermally treated materials were characterized by room temperature XRD. The sequence of thermal transformations that Ba-exchanged zeolite A undergoes (zeolite ® amorphous phase ® hexacelsian ® monoclinic celsian) and the strong mineralizing action developed by Na are confirmed. Pressing the Ba-exchanged zeolite A powder-like samples to obtain cylindrical pellets is found to expedite the sluggish final phase transition hexacelsian ® monoclinic celsian. The optimum residual Na content of Ba-exchanged zeolite A to be transformed into monoclinic celsian is assessed to range between 0.27 and 0.43 meq/g.

External electric field promotes proton transfer in the radical cation of adenine–thymine

2016 ◽  
Vol 30 (21) ◽  
pp. 1650276 ◽  
Author(s):  
Guiqing Zhang ◽  
Shijie Xie
Keyword(s):  
Electric Field ◽  
Proton Transfer ◽  
External Electric Field ◽  
Radical Cation ◽  
Base Pair ◽  
Low Temperatures ◽  
Room Temperature ◽  
Theoretical Calculations ◽  
Base Pairs ◽  
Adenine Thymine

According to [Formula: see text] measurements, it has been predicted that proton transfer would not occur in the radical cation of adenine–thymine (A:T). However, recent theoretical calculations indicate that proton transfer takes place in the base pair in water below the room temperature. We have performed simulations of proton transfer in the cation of B-DNA stack composed of 10 A:T base pairs in water from 20 K to 300 K. Proton transfer occurs below the room temperature, meanwhile it could also be observed at the room temperature under the external electric field. Another case that interests us is that proton transfer bounces back after [Formula: see text][Formula: see text]300 fs from the appearance of proton transfer at low temperatures.

Accessing 1,2-Amino Alcohols and Diols through Photocatalytic Anti-Markovnikov Difunctionalisation of Ene-Carbamates and Enol Ethers

2020 ◽  
Author(s):  
Jerome Waser ◽  
Stefano Nicolai ◽  
Stephanie G. E. Amos
Keyword(s):  
Double Bond ◽  
Radical Cation ◽  
Amino Alcohol ◽  
Oxygen Transfer ◽  
Room Temperature ◽  
Organic Dye ◽  
Enol Ethers ◽  
Blue Led ◽  
Broad Variety ◽  
Led Irradiation

We report an atom-economical 1,2-oxyalkynylation of ene-carbamates and enol ethers based on the use of Ethynyl BenziodoXolone (EBX) as dual reagents for alkyne and oxygen transfer. The reaction occurs at room temperature under blue LED irradiation using an organic dye as a photocatalyst. A broad variety of 1-alkynyl-1,2-amino-alcohol and 1-alkynyl-1,2-diol scaffolds were obtained in up to 89% yield with anti-Markovnikov regioselectivity. The reaction is speculated to proceed via oxidation of the double bond to give a radical cation intermediate, enabling the selective difunctionalization of electron-rich alkenes.

Local structure change of luminescent Ag zeolite-A and -X studied by in situ XAFS and IR spectroscopy

2020 ◽  
Vol 27 (6) ◽  
pp. 1640-1647
Author(s):  
Takafumi Miyanaga ◽  
Yushi Suzuki ◽  
Sho Narita ◽  
Reki Nakamura
Keyword(s):  
Local Structure ◽  
Room Temperature ◽  
Structural Changes ◽  
Zeolite A ◽  
Zeolite X ◽  
Zeolite Cavity ◽  
Ag Clusters ◽  
The Difference ◽  
X Ray Absorption

The in situ X-ray absorption fine structure (XAFS) for the structural changes of Ag clusters produced in the cavity of luminescent zeolites by thermal treatment of Ag zeolite-A and Ag zeolite-X has been studied. The following procedures are compared: (i) samples are heated and cooled to room temperature under atmosphere (under air); (ii) samples are heated and cooled to room temperature in a vacuum and then exposed to air. It was confirmed that the Ag clusters were broken when the Ag zeolite was exposed to air for Ag zeolite-X, which complements our previous results for Ag12-A. It is suggested that the deformation of the Ag clusters plays an important role in the generation of a strong photoluminescence band, and Ag clusters may not be direct species producing the strong photoluminescence. The local structure of the Ag ions was found to be slightly different from that of the unheated species. The difference may originate from the formation and breakdown of Ag clusters in the zeolite cavity.

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