La décomposition du tétraméthylgermane par les atomes Hg 6(3P1)

1973 ◽  
Vol 51 (18) ◽  
pp. 3062-3064 ◽  
Author(s):  
Jocelyn Duval ◽  
Yves Rousseau
Keyword(s):  
Quantum Yield ◽  
Bond Cleavage ◽  
Primary Process ◽  
Methyl Radicals ◽  
Mild Conditions

The primary process in the mercury photosensitized decomposition of tetramethylgermane is a C—H bond cleavage. The hydrogen quantum yield, extrapolated at infinite pressure, is close to unity. Under mild conditions, hydrogen and 1,2-di(trimethylgermyl) ethane are the only products observed. At high intensities and low substrate pressures, atomic cracking occurs yielding methyl radicals which lead to the formation of methane.

Primary process(es) in the mercury-photosensitized decomposition of dimethyl ether at 2537 Å

1968 ◽  
Vol 46 (16) ◽  
pp. 2693-2697 ◽  
Author(s):  
R. Payette ◽  
M. Bertrand ◽  
Y. Rousseau
Keyword(s):  
Carbon Monoxide ◽  
Quantum Yield ◽  
Light Intensity ◽  
Dimethyl Ether ◽  
Molecular Hydrogen ◽  
Room Temperature ◽  
Primary Process ◽  
Methyl Radicals ◽  
Hydrogen Atoms ◽  
Radical Recombination

The mercury-photosensitized decomposition of dimethyl ether has been studied at room temperature and at pressures ranging from 10 to 200 Torr.The formation of an excited dimethyl ether (DME) molecule has been verified by following the rates of formation of methane, ethane, and carbon monoxide with various ether pressures.The study of the variation of the quantum yield of molecular hydrogen formation with absorbed light intensity at high ether pressures has shown that the primary process involves the dissociation of ether molecules into hydrogen atoms and methoxy methyl radicals:[Formula: see text]The results presented in this paper indicate that the excited DME molecule can originate in a radical recombination between hydrogen atoms and methoxy methyl radicals.

Electron Donation by Low-Crystalline Ba-La-Ce Oxygen-Deficient Composite Oxide Accumulating on Ru Nanoparticles for Ammonia Synthesis under Mild Conditions

2019 ◽  
Author(s):  
Katsutoshi Sato ◽  
Shin-ichiro Miyahara ◽  
Yuta Ogura ◽  
Kotoko Tsujimaru ◽  
Yuichiro Wada ◽  
...  
Keyword(s):  
Ammonia Synthesis ◽  
Bond Cleavage ◽  
Synthesis Process ◽  
Strong Electron ◽  
Mild Conditions ◽  
Ru Nanoparticles ◽  
Rate Determining Step ◽  
Highly Active ◽  
Composite Oxides ◽  
Low Crystalline

<p>To mitigate global problems related to energy and global warming, it is helpful to develop an ammonia synthesis process using catalysts that are highly active under mild conditions. Here we show that the ammonia synthesis activity of Ru/Ba/LaCeO<i><sub>x</sub></i> pre-reduced at 700 °C is the highest reported among oxide-supported Ru catalysts. Our results indicate that low crystalline oxygen-deficient composite oxides, which include Ba<sup>2+</sup>, Ce<sup>3+</sup> and La<sup>3+</sup>, with strong electron-donating ability, accumulate on Ru particles and thus promote N≡N bond cleavage, which is the rate determining step for ammonia synthesis.</p>

Electron Donation by Low-Crystalline Ba-La-Ce Oxygen-Deficient Composite Oxide Accumulating on Ru Nanoparticles for Ammonia Synthesis under Mild Conditions

2019 ◽  
Author(s):  
Katsutoshi Sato ◽  
Shin-ichiro Miyahara ◽  
Yuta Ogura ◽  
Kotoko Tsujimaru ◽  
Yuichiro Wada ◽  
...  
Keyword(s):  
Ammonia Synthesis ◽  
Bond Cleavage ◽  
Synthesis Process ◽  
Strong Electron ◽  
Mild Conditions ◽  
Ru Nanoparticles ◽  
Rate Determining Step ◽  
Highly Active ◽  
Composite Oxides ◽  
Low Crystalline

<p>To mitigate global problems related to energy and global warming, it is helpful to develop an ammonia synthesis process using catalysts that are highly active under mild conditions. Here we show that the ammonia synthesis activity of Ru/Ba/LaCeO<i><sub>x</sub></i> pre-reduced at 700 °C is the highest reported among oxide-supported Ru catalysts. Our results indicate that low crystalline oxygen-deficient composite oxides, which include Ba<sup>2+</sup>, Ce<sup>3+</sup> and La<sup>3+</sup>, with strong electron-donating ability, accumulate on Ru particles and thus promote N≡N bond cleavage, which is the rate determining step for ammonia synthesis.</p>

ChemInform Abstract: Metal Triflate-Catalyzed Se-Se Bond Cleavage and the Selective Additions under Mild Conditions.

ChemInform ◽  
2011 ◽  
Vol 43 (1) ◽  
pp. no-no
Author(s):  
Lei Yu ◽  
Lingfeng Ren ◽  
Rong Guo ◽  
Tian Chen
Keyword(s):  
Bond Cleavage ◽  
Mild Conditions

Organophosphane-Catalyzed Construction of Functionalized 2-Ylideneoxindoles via Direct β-Acylation

Synthesis ◽  
2021 ◽  
Author(s):  
Wey-Chyng Jeng ◽  
Po-Chung Chien ◽  
Sandip Sambhaji Vagh ◽  
Athukuri Edukondalu ◽  
Wenwei Lin
Keyword(s):  
Intramolecular Cyclization ◽  
Efficient Method ◽  
Bond Cleavage ◽  
Scale Up ◽  
Acyl Chlorides ◽  
Metal Free ◽  
Mild Conditions ◽  
Synthetic Utility ◽  
Mechanistic Investigations ◽  
Synthetic Transformations

We report an efficient method for the direct β-acylation of 2-ylideneoxindoles with acyl chlorides in the presence of base-catalyzed by organophosphanes. A variety of functionalized 2-ylideneoxindoles were prepared in moderate to good yields under metal-free and mild conditions via a tandem phospha-Michael/O-acylation/intramolecular cyclization/ rearrangement sequence. The mechanistic investigations revealed that the C-O bond cleavage on possible betaine intermediate is the key step for the installation of keto-functionality at β-position of 2-ylideneoxindoles in a highly stereospecific manner. The synthetic utility of this protocol could also be proven by scale-up reactions and synthetic transformations of the products.

Hg(63P1)-sensitized decomposition of HNCO vapor and HNCO–H2 mixtures; the reaction of hydrogen atoms with HNCO

1968 ◽  
Vol 46 (4) ◽  
pp. 527-530 ◽  
Author(s):  
N. J. Friswell ◽  
R. A. Back
Keyword(s):  
Quantum Yield ◽  
Cross Section ◽  
Initial Step ◽  
Primary Process ◽  
Hydrogen Atoms ◽  
Direct Photolysis ◽  
A Value ◽  
The Cross

The Hg(63P1)-sensitized decomposition of HNCO vapor has been briefly studied at 26 °C with HNCO pressures from about 3 to 30 Torr. The products detected were the same as in the direct photolysis, CO, N2, and H2. The quantum yield of CO was appreciably less than unity, compared with a value of 1.5 in the direct photolysis under similar conditions. From this and other observations it is tentatively concluded that a single primary process occurs:[Formula: see text]From a study of the mercury-photosensitized reactions in mixtures of HNCO with H2, it was concluded that hydrogen atoms react with HNCO to form CO but not N2. The initial step is probably addition to form NH2CO. From the competition between reaction [1] and the corresponding quenching by H2, the cross section for reaction [1] was estimated to be 2.3 times that of hydrogen.

Palladium-Catalyzed Desulfurative Hiyama Coupling of Thioureas to Achieve Amides via Selective C–N Bond Cleavage

Synthesis ◽  
2021 ◽  
Author(s):  
Zhuo Zeng ◽  
Zhanyu He ◽  
Chu Yan ◽  
Mei Zhang ◽  
Majeed Irfan ◽  
...  
Keyword(s):  
Good Yield ◽  
Bond Cleavage ◽  
New Approach ◽  
Mild Conditions ◽  
Palladium Catalyzed

AbstractPalladium-catalyzed Hiyama coupling of active thioureas via selective C–N bond cleavage is reported. Notably, the new approach employed active thioureas as coupling partners in the presence of arylsilanes to give amides in good yield. Further, this strategy, which utilized CuF2 as a key oxidant and activator, afforded various amide products under mild conditions and an easy to handle procedure without extra base.

scholarly journals Decarbonylation through Aldehydic C–H Bond Cleavage by a Cationic Iridium Catalyst

Synlett ◽  
2019 ◽  
Vol 30 (08) ◽  
pp. 972-976 ◽  
Author(s):  
Tomohiko Shirai ◽  
Kazuki Sugimoto ◽  
Masaya Iwasaki ◽  
Ryuki Sumida ◽  
Harunori Fujita ◽  
...  
Keyword(s):  
Bond Cleavage ◽  
Catalyst System ◽  
Mild Conditions ◽  
Iridium Catalyst ◽  
Reaction Proceeds ◽  
High Yields

We report the decarbonylation of aldehydes through an aldehydic C–H bond cleavage catalyzed by a cationic iridium/bisphosphine catalyst. The reaction proceeds under relatively mild conditions to give the corresponding hydrocarbon products in moderate to high yields. In addition, this cationic iridium catalyst system can be applied to an asymmetric hydroacylation of ketones.

Carbon–Carbon Bond Cleavage and Esterification of Phenylacetonitrile and its Derivatives Affording the Corresponding Benzoic Esters

2007 ◽  
Vol 2007 (6) ◽  
pp. 323-324 ◽  
Author(s):  
Zhiyuan Wang ◽  
Junhui Kang ◽  
Mingxin Yu
Keyword(s):  
Potassium Iodide ◽  
Elemental Analysis ◽  
Bond Cleavage ◽  
Carbon Bond ◽  
H Nmr ◽  
Mild Conditions ◽  
Carbon Carbon Bond

Phenylacetonitrile and its derivatives were treated with alcohols in the presence of potassium iodide and iodine affording the corresponding benzoate esters via degradation, oxidation and esterification under mild conditions. The products were characterised by IR, 1H NMR, MS and elemental analysis.

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