China
Africa
Explore chapters and articles related to this topic
Introduction to Organometallics
Published in Samir H. Chikkali, Metal-Catalyzed Polymerization, 2017
Samir H. Chikkali, Sandeep Netalkar
There are two main types of insertion reactions commonly encountered in organometallic chemistry and catalysis: 1,1-migratory insertion and 1,2-migratory insertion. In 1,1-insertion the same atom (1,1) of the inserting group (M-Y1,1(E)-Z atom of say Y = Z) binds the metal and displaces X-type ligand, whereas in 1,2-insertion the metal and the displaced X-type ligands E are bound to the adjacent atoms (1,2) of the inserting ligands (M-Y1-Z2-E). The nature of the inserting 2e– unsaturated π-ligand and topology of coordination has an influence on the type of insertion that takes place. The best examples are of C=O and C=C insertions, carbon monoxide being a monohaptic ligand, η1-C=O, η1 (C) always inserts in 1,1 fashion (Figure 1.25a) while the dihaptic alkene such as ethylene, η2->C=C<, η2 (C, C) prefers 1,2 insertion (Figure 1.25b). The only common ligand that can undergo both 1,1 and 1,2 insertion is SO2, since it can be a monohaptic, η1, (S) or dihaptic, η2, (S, O) donor.
A Comparison of three Degradative Pre-Treatment Processes for Dye Wastes
Published in Nada Assaf-Anid, Hazardous and Industrial Wastes Proceedings of the Thirty-Third Mid-Atlantic Industrial and Hazardous Waste Conference, 2001
Ozone is one of the most powerful known oxidising agents and is used to degrade organic contaminants present in water supplies and in wastewater [11]. Ozonation for dye decolourisation has been demonstrated at laboratory scale for a broad range of dyes [12,13]. A number of different ozone-dye reactions have been reported. These include addition reactions during which ozonides are formed and ultimately carbonyl compounds and peroxides. Insertion reactions, electrophilic and nucleophilic attack and electron transfer have also been reported [12]. Ozonation can also decolourise dyes by the reaction of free radicals formed as a result of ozone decomposition. This decomposition proceeds by way of the formation of OH•, HO2• and HO3•.
Ti-Fe-Si/C composites as anode materials for high energy li-ion batteries
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2022
Bage Alhamdu Nuhu, Humphrey Adun, Olusola Bamisile, Mustapha Mukhtar
Generation of energy from renewable sources with the commensurate fabrication of storage systems and devices for intermittent supply of electricity is of the essence. Battery systems including Lithium-ion batteries (LIBs) can be coupled with photovoltaics (PV) to form PV-battery stationary systems at the level of communal grids (Jenu et al. 2020). The growing demand for greener alternative renewable sources of energy for electricity production, electric vehicles (EV), hybrid electric vehicles (HEV), portable devices, and so on have brought the LIBs research into limelight. This ever-increasing demand, which accounts for the application of LIBs as energy storage devices is basically because of its constitutive chemistries, such as lightweight, high energy and power density, low discharge rate low emission, fast cyclability, high efficiencies, and low cost (Tarascon and Armand 2010). LIBs consist of the electrodes cathode (positive) and anode (negative), separator, and electrolyte. The cathode undergoes an oxidation reaction and supplies Li+ to the anode electrode where reduction takes place. Traditional carbon anodes undergo an insertion reaction mechanism yielding low theoretical capacity (372 mAh g−1 based on LiC6) as it only allows for low insertion of lithium ions into the material matrix (Figure 1). Although carbon undergoes small and reversible structural changes, the formation of Li+ dendrites accounts for the low intercalation voltage (<0.1 V vs. Li+ /Li) (Zhe et al. 2013).
Dynamics studies of O+ + D2 reaction using the time-dependent wave packet method
Published in Molecular Physics, 2020
Ziliang Zhu, Li Li, Qiju Li, Bing Teng
Quantum mechanical calculations of O+ + D2(v = 0, j = 0) → OD+ + D reaction were carried out at the state-to-state level of theory. The total reaction probability and total ICS show no threshold and decrease with increasing collision energy. The total ICS is comparable to reported experimental data. Furthermore, our results are in good agreement with this data, although some discrepancies arise, especially at low collision energy region. In the case of DCS, both results show a forward–backward symmetry for all collision energies because the intermediate possesses a suitable half-life for decay into any reachable channel. The obtained results indicate that the insertion reaction mechanism plays an important role in O+ + D2(v = 0, j = 0) → OD+ + D reaction.
Isotopic effects of the N(2D) + H2 → NH + H reaction: a quantum time-dependent wave packet investigation
Published in Molecular Physics, 2020
Three-dimensional plots of the total DCSs of N(2D) +H2/HD/D2 reactions as a function internal coordinate are presented in Figure 6. Both angular distributions display peaks at two extreme angles (0° and 180°) at all collision energies of the four maps. The forward–backward symmetry DCSs stem from the deep well on the reaction path, the lifetime of complex is long enough to decay into the product channel or reactant channel. This implies that the insertion reaction mechanism is dominant in the reaction and statistical model is suitable for these reactions.