Preparation of di-.pi.-cyclooctatetraene complexes of uranium, thorium, and plutonium by direct reaction of the metals with cyclooctatetraene

1973 ◽  
Vol 95 (10) ◽  
pp. 3423-3424 ◽  
Author(s):  
David F. Starks ◽  
Andrew. Streitwieser
Keyword(s):  
Direct Reaction

Continuous Ozonation of Polycyclic Aromatic Hydrocarbons in Oil/Water-Emulsions and Biodegradation of Oxidation Products

1999 ◽  
Vol 40 (4-5) ◽  
pp. 107-114 ◽  
Author(s):  
A. Kornmüller ◽  
U. Wiesmann
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Biological Treatment ◽  
Reaction Rate ◽  
Oxidation Products ◽  
Direct Reaction ◽  
Biological Degradation ◽  
Polycyclic Aromatic ◽  
Oil Water ◽  
Treatment Step

The continuous ozonation of polycyclic aromatic hydrocarbons (PAH) was studied in a two stage ozonation system followed by serobic biological degradation. The highly condensed PAH benzo(e)pyrene and benzo(k)fluoranthene were oxidized selectiely in synthetic oil/water-emulsions. The influence of the ozone mass transfer gas-liquid on the reaction rate of benzo(k)fluoranthene was studied for process optimization. The dissolved ozone concentration is influenced by temperature to a higher degree than the reaction rate of PAH. In dependence on pH, PAH oxidation occurs by a direct reaction with ozone inside the oil droplets. Two main ozonation products of benzo(e)pyrene were quantified at different retention times during ozonation and their transformation could be shown in the biological treatment step.

scholarly journals Synthesis and Compressibility of Novel Nickel Carbide at Pressures of Earth’s Outer Core

Minerals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 516
Author(s):  
Timofey Fedotenko ◽  
Saiana Khandarkhaeva ◽  
Leonid Dubrovinsky ◽  
Konstantin Glazyrin ◽  
Pavel Sedmak ◽  
...  
Keyword(s):  
Equation Of State ◽  
Outer Core ◽  
Direct Reaction ◽  
Volume Data ◽  
X Ray Diffraction ◽  
Nickel Carbide ◽  
Diamond Anvils ◽  
Group A ◽  
Diamond Anvil ◽  
Murnaghan Equation

We report the high-pressure synthesis and the equation of state (EOS) of a novel nickel carbide (Ni3C). It was synthesized in a diamond anvil cell at 184(5) GPa through a direct reaction of a nickel powder with carbon from the diamond anvils upon heating at 3500 (200) K. Ni3C has the cementite-type structure (Pnma space group, a = 4.519(2) Å, b = 5.801(2) Å, c = 4.009(3) Å), which was solved and refined based on in-situ synchrotron single-crystal X-ray diffraction. The pressure-volume data of Ni3C was obtained on decompression at room temperature and fitted to the 3rd order Burch-Murnaghan equation of state with the following parameters: V0 = 147.7(8) Å3, K0 = 157(10) GPa, and K0' = 7.8(6). Our results contribute to the understanding of the phase composition and properties of Earth’s outer core.

scholarly journals Solvent-free synthesis of symmetric methylene diesters via direct reaction of aromatic carboxylates with 1,n-dihaloalkanes

RSC Advances ◽  
2021 ◽  
Vol 11 (46) ◽  
pp. 28711-28715
Author(s):  
Lin Bai ◽  
Shenglong Ding ◽  
Xiaofang Ma
Keyword(s):  
Solvent Free ◽  
Direct Reaction ◽  
Highly Efficient ◽  
Solvent Free Conditions ◽  
Aromatic Carboxylates ◽  
Solvent Free Synthesis

This work provides a highly efficient and feasible strategy for the synthesis of symmetric methylene diesters, involving the direct diesterification of various carboxylates with 1,n-dihaloalkanes under solvent-free conditions.

scholarly journals New Direct Reaction: Two-Proton Knockout from Neutron-Rich Nuclei

2003 ◽  
Vol 91 (1) ◽  
Author(s):  
D. Bazin ◽  
B.  A. Brown ◽  
C.  M. Campbell ◽  
J.  A. Church ◽  
D.  C. Dinca ◽  
...  
Keyword(s):  
Direct Reaction ◽  
Proton Knockout

A direct reaction approach for the synthesis of zeolitic imidazolate frameworks: template and temperature mediated control on network topology and crystal size

2012 ◽  
Vol 48 (79) ◽  
pp. 9930 ◽  
Author(s):  
Mónica Lanchas ◽  
Daniel Vallejo-Sánchez ◽  
Garikoitz Beobide ◽  
Oscar Castillo ◽  
Andrés T. Aguayo ◽  
...  
Keyword(s):  
Network Topology ◽  
Crystal Size ◽  
Direct Reaction ◽  
Zeolitic Imidazolate Frameworks

scholarly journals Oxygen activation in neuronal NO synthase: resolving the consecutive mono-oxygenation steps

2012 ◽  
Vol 443 (2) ◽  
pp. 505-514 ◽  
Author(s):  
Davide Papale ◽  
Chiara Bruckmann ◽  
Ben Gazur ◽  
Caroline S. Miles ◽  
Christopher G. Mowat ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Direct Reaction ◽  
Chemical Mechanisms ◽  
Signalling Molecule ◽  
Proton Source ◽  
In The Wild ◽  
Additional Hydrogen Bond ◽  
Oxide Synthase ◽  
Haem Iron ◽  
Additional Hydrogen

The vital signalling molecule NO is produced by mammalian NOS (nitric oxide synthase) enzymes in two steps. L-arginine is converted into NOHA (Nω-hydroxy-L-arginine), which is converted into NO and citrulline. Both steps are thought to proceed via similar mechanisms in which the cofactor BH4 (tetrahydrobiopterin) activates dioxygen at the haem site by electron transfer. The subsequent events are poorly understood due to the lack of stable intermediates. By analogy with cytochrome P450, a haem-iron oxo species may be formed, or direct reaction between a haem-peroxy intermediate and substrate may occur. The two steps may also occur via different mechanisms. In the present paper we analyse the two reaction steps using the G586S mutant of nNOS (neuronal NOS), which introduces an additional hydrogen bond in the active site and provides an additional proton source. In the mutant enzyme, BH4 activates dioxygen as in the wild-type enzyme, but an interesting intermediate haem species is then observed. This may be a stabilized form of the active oxygenating species. The mutant is able to perform step 2 (reaction with NOHA), but not step 1 (with L-arginine) indicating that the extra hydrogen bond enables it to discriminate between the two mono-oxygenation steps. This implies that the two steps follow different chemical mechanisms.

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