Methanediide Formation via Hydrogen Elimination in Magnesium versus Aluminium Hydride Complexes of a Sterically Demanding Bis(iminophosphoranyl)methanediide

Substituted bis(iminophosphoranyl)methanes are CH acidic compounds that can form complexes with formally dianionic central carbon centres. The reaction of H2C(Ph2P=NDip)2 (&equiv; H2L), Dip = 2,6-diisopropylphenyl, with one equivalent of di-n-butylmagnesium afforded the methanide complex [HLMgnBu] 1. Treatment of complex 1 with phenylsilane in aromatic solvents at elevated temperatures afforded the methanediide complex [(LMg)2] 2 presumably via the MgH intermediate [(HLMgH)n] (n = 1 or 2). The reaction of 1 with LiAlH4 in diethyl ether yielded the AlH complex [HLAlH2] 3. Alternatively, this complex was also obtained from the reaction of H2L with AlH3∙NMe3. The molecular structures of [HLMgnBu] 1, [(LMg)2] 2, and [HLAlH2] 3 are reported. Complex 3 shows no sign of H2 elimination to a methanediide species at elevated temperatures in contrast to the facile elimination of the putative reaction intermediate [(HLMgH)n] (n = 1 or 2) to form [(LMg)2] 2. The chemical properties of complex 2 were investigated and this complex appears to be stable against coordination with strong donor molecules.

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Methanediide Formation via Hydrogen Elimination in Magnesium versus Aluminium Hydride Complexes of a Sterically Demanding Bis(iminophosphoranyl)methanediide

Inorganics ◽

10.3390/inorganics5020029 ◽

2017 ◽

Vol 5 (2) ◽

pp. 29 ◽

Cited By ~ 2

Author(s):

Christian Sindlinger ◽

Samuel Lawrence ◽

David Cordes ◽

Alexandra Slawin ◽

Andreas Stasch

Keyword(s):

Hydride Complexes ◽

Hydrogen Elimination ◽

Sterically Demanding

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Carbon Nanotube Production From Ethylene in CO2/N2 Environments

Journal of Energy Resources Technology ◽

10.1115/1.4039328 ◽

2018 ◽

Vol 140 (8) ◽

Cited By ~ 1

Author(s):

Chuanwei Zhuo ◽

Henning Richter ◽

Yiannis A. Levendis

Keyword(s):

Elevated Temperatures ◽

High Surface ◽

Catalyst Support ◽

Chemical Properties ◽

Chemical Vapor ◽

Abundant Species ◽

Chemical Kinetic ◽

Chemical Kinetic Model ◽

Hydrogen Elimination ◽

Experimental Findings

Carbon nanotubes (CNTs) have high surface areas and excellent mechanical, electrical, and chemical properties, thus they can be useful in applications related to extraction and conversion of energy. They can be readily produced from hydrocarbon feedstocks. In this work, ethylene, the most voluminously produced hydrocarbon, was used as a CNT feedstock. It was pyrolytically decomposed at elevated temperatures (984–1130 K) to generate CNTs, by catalytic chemical vapor deposition (CVD) on stainless steel substrates. To explore possible utilization of carbon dioxide, a typical combustion byproduct, the ethylene gas was introduced to a preheated CVD reactor at the presence of various amounts of CO2, in a balance of inert nitrogen gas. The ethylene pyrolyzates were assessed at the presence/absence of catalysts and CO2 to identify the gaseous carbon growth agents. Experimental findings were also contrasted to predictions of a detailed chemical kinetic model. It was found that whereas decomposition of ethylene was somewhat inhibited by CO2 at the presence of the catalyst support, its conversion to CNTs was promoted. CNTs consistently formed at 5% CO2. Maximum yields of CNTs occurred at 1130 K, whereas highest CNT quality was achieved at 1080 K. Hydrogen and 1,3-butadiene (C4H6) were experimentally found to be the most abundant species of ethylene thermal decomposition. This was in agreement with the model, which also highlighted the importance of unimolecular hydrogen elimination.

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Design and Synthesis of Fluoro Analogues of Vitamin D

International Journal of Molecular Sciences ◽

10.3390/ijms22158191 ◽

2021 ◽

Vol 22 (15) ◽

pp. 8191

Author(s):

Fumihiro Kawagoe ◽

Sayuri Mototani ◽

Atsushi Kittaka

Keyword(s):

Vitamin D ◽

Vitamin D3 ◽

Fluorine Atom ◽

Chemical Properties ◽

Molecular Structures ◽

Physical And Chemical Properties ◽

Design And Synthesis ◽

Synthetic Methodologies ◽

Physical And Chemical ◽

And Chemical Properties

The discovery of a large variety of functions of vitamin D3 and its metabolites has led to the design and synthesis of a vast amount of vitamin D3 analogues in order to increase the potency and reduce toxicity. The introduction of highly electronegative fluorine atom(s) into vitamin D3 skeletons alters their physical and chemical properties. To date, many fluorinated vitamin D3 analogues have been designed and synthesized. This review summarizes the molecular structures of fluoro-containing vitamin D3 analogues and their synthetic methodologies.

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Characterization of Thermophilic Bacteria Using Surface-Enhanced Raman Scattering

Applied Spectroscopy ◽

10.1366/000370208786401545 ◽

2008 ◽

Vol 62 (11) ◽

pp. 1226-1232 ◽

Cited By ~ 42

Author(s):

Mustafa Çulha ◽

Ahmet Adigüzel ◽

M. MÜGE Yazici ◽

Mehmet Kahraman ◽

Fikrettin Slahin ◽

...

Keyword(s):

Cell Wall ◽

Raman Scattering ◽

Elevated Temperatures ◽

Thermophilic Bacteria ◽

Surface Enhanced Raman Scattering ◽

Molecular Structures ◽

E Coli ◽

Surface Enhanced ◽

Surface Enhanced Raman ◽

Enhanced Raman Scattering

Surface-enhanced Raman scattering (SERS) can provide molecular-level information about the molecules and molecular structures in the vicinity of nanostructured noble metal surfaces such as gold and silver. The three thermophilic bacteria Bacillus licheniformis, Geobacillus stearothermophilus, and Geobacillus pallidus, a Gram-negative bacterium E. coli, and a Gram-positive bacterium B. megaterium are comparatively characterized using SERS. The SERS spectra of thermophilic bacteria are similar, while they show significant differences compared to E. coli and B. megaterium. The findings indicate that a higher number of thiol residues and possible S–S bridges are present in the cell wall structure of thermophilic bacteria, providing their stability at elevated temperatures. Incubating the thermophilic bacteria with colloidal silver suspension at longer times improved the bacteria–silver nanoparticle interaction kinetics, while increased temperature does not have a pronounced effect on spectral features. A tentative assignment of the SERS bands was attempted for thermophilic bacteria. The results indicate that SERS can be a useful tool to study bacterial cell wall molecular differences.

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Experimental Investigation on Grinding Temperature of Titanium Alloy

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1027.127 ◽

2014 ◽

Vol 1027 ◽

pp. 127-130 ◽

Cited By ~ 1

Author(s):

Bing Jun Hao ◽

Zhi Gang Dong ◽

Ren Ke Kang ◽

Huan Wang ◽

Ke Cao

Keyword(s):

Titanium Alloy ◽

Structural Changes ◽

Thermal Damage ◽

Elevated Temperatures ◽

Chemical Properties ◽

Grinding Temperature ◽

Physical And Chemical Properties ◽

Machine Material ◽

Physical And Chemical ◽

And Chemical Properties

Titanium alloy has been widely used in aeronautics and astronautics industry owing to its unique combinations of properties. The unique physical and chemical properties of titanium alloy make it a typical difficult-to-machine material. The elevated temperatures at the machining zones may cause thermal damage, residual stress and micro-structural changes in the surface layer of titanium alloy during grinding. In this study, grinding experiments were performed on the titanium alloy, and the grinding temperature was experimentally tested with the grindable thermocouples. The effects of the grinding parameters on the grinding temperature were analyzed. The grinding temperature rises with the increase of grinding speed and grinding depth.

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Characteristics and Applications of Nanostructured Nitrides Synthesized by Vapor Phase Reactions

MRS Proceedings ◽

10.1557/proc-876-r8.51 ◽

2005 ◽

Vol 876 ◽

Author(s):

Gerald Ziegenbalg ◽

Carsten Pätzold ◽

Ute Ŝingliar ◽

Rico Berthold

Keyword(s):

Silicon Nitride ◽

Amorphous Silicon ◽

Vapor Phase ◽

Elevated Temperatures ◽

Catalyst Support ◽

Chemical Properties ◽

Molar Ratio ◽

Basic Catalyst ◽

Metal Chlorides ◽

Amorphous Silicon Nitride

AbstractGas phase ammonolysis of volatile metal chlorides at elevated temperatures is a favorable way to produce nitride or oxynitride nanopowders. Their composition as well as the physico-chemical properties is determined by reaction temperature, molar ratio of the reactants and the residence time of the gases in the reaction zone. Both single and multi component powders can be obtained. Typical particle sizes are in the range of 50 to 350 nm. The specific surface can reach values up to 300 m2/g. Microporous analysis revealed the presence of pores with a diameter between 0.6 and 0.7 nm in amorphous silicon nitride. The powders can be used, depending on the characteristics, as catalyst or basic catalyst support. The paper gives an overview about vapor phase synthesis of single and multi component nitrides as well as the use of amorphous silicon nitride as a basic catalyst support for dehydrogenation of propane.

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Research on Physico-Chemical Properties of Diethyl Ether/Linseed Oil Blends for the Use as Fuel in Diesel Engines

Energies ◽

10.3390/en13246564 ◽

2020 ◽

Vol 13 (24) ◽

pp. 6564

Author(s):

Krzysztof Górski ◽

Ruslans Smigins ◽

Rafał Longwic

Keyword(s):

Surface Tension ◽

Low Temperature ◽

Diethyl Ether ◽

Diesel Fuel ◽

Diesel Engines ◽

Kinematic Viscosity ◽

Linseed Oil ◽

Chemical Properties ◽

Fuel Blends ◽

Physico Chemical

Physico-chemical properties of diethyl ether/linseed oil (DEE/LO) fuel blends were empirically tested in this article for the first time. In particular, kinematic viscosity (ν), density (ρ), lower heating value (LHV), cold filter plugging point (CFPP) and surface tension (σ) were examined. For this research diethyl ether (DEE) was blended with linseed oil (LO) in volumetric ratios of 10%, 20% and 30%. Obtained results were compared with literature data of diethyl ether/rapeseed oil (DEE/RO) fuel blends get in previous research in such a way looking on differences also between oil types. It was found that DEE impacts significantly on the reduction of plant oil viscosity, density and surface tension and improve low temperature properties of tested oils. In particular, the addition of 10% DEE to LO effectively reduces its kinematic viscosity by 53% and even by 82% for the blend containing 30% DEE. Tested ether reduces density and surface tension of LO up to 6% and 25% respectively for the blends containing 30% DEE. The measurements of the CFPP showed that DEE significantly improves the low temperature properties of LO. In the case of the blend containing 30% DEE the CFPP can be lowered up to −24 °C. For this reason DEE/LO blends seem to be valuable as a fuel for diesel engines in the coldest season of the year. Moreover, DEE/LO blends have been tested in the engine research. Based on results it can be stated that the engine operated with LO results in worse performance compared with regular diesel fuel (DF). However, it was found that these disadvantages could be reduced with DEE as a component of the fuel mixture. Addition of this ether to LO improves the quality of obtained fuel blends. For this reason, the efficiency of DEE/LO blend combustion process is similar for the engine fuelled with regular diesel fuel. In this research it was confirmed that the smoke opacity reaches the highest value for the engine fuelled with plant oils. However, addition of 20% DEE reduces this emission to the value comparable for the engine operated with diesel fuel.

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