Balancing redox equations through zero oxidation number method

Many high school students and first-year undergraduate students find it difficult to balance redox reactions. A method using zero oxidation number to balance redox equations is presented herein. This method may shorten the balancing time and lessen the effort. It is a helpful complement to the traditional oxidation number method and half-reaction method.

Interfacial reactions in lithia-based cathodes depending on the binder in the electrode and salt in the electrolyte

Lithia (Li2O)-based cathodes, utilizing oxygen redox reactions for obtaining capacity, exhibit higher capacity than commercial cathodes. However, they are highly reactive owing to superoxides formed during charging, and they enable more active parasitic (side) reactions at the cathode/electrolyte and cathode/binder interfaces than conventional cathodes. This causes deterioration of the electrochemical performance limiting commercialization. To address these issues, the binder and salt for electrolyte were replaced in this study to reduce the side reaction of the cells containing lithia-based cathodes. The commercially used polyvinylidene fluoride (PVDF) binder and LiPF6 salt in the electrolyte easily generate such reactions, and the subsequent reaction between PVDF and LiOH (from decomposition of lithia) causes slurry gelation and agglomeration of particles in the electrode. Moreover, the fluoride ions from PVDF promote side reactions, and LiPF6 salt forms POF3 and HF, which cause side reactions owing to hydrolysis in organic solvents containing water. However, the polyacrylonitrile (PAN) binder and LiTFSI salt decrease these side reactions owing to their high stability with lithia-based cathode. Further, thickness of the interfacial layer was reduced, resulting in decreased impedance value of cells containing lithia-based cathodes. Consequently, for the same lithia-based cathodes, available capacity and cyclic performance were increased owing to the effects of PAN binder and LiTFSI salt in the electrolyte.

14 Electrochemistry in Natural Product Synthesis

The multistep synthesis of natural products has historically served as a useful and informative platform for showcasing the best, state-of-the-art synthetic methodologies and technologies. Over the last several decades, electrochemistry has proved itself to be a useful tool for conducting redox reactions. This is primarily due to its unique ability to selectively apply any oxidizing or reducing potential to a sufficiently conductive reaction solution. Electrochemical redox reactions are readily scaled and can be more sustainable than competing strategies based on conventional redox reagents. In this chapter, we summarize the examples where electrochemistry has been used in the synthesis of natural products. The chapter is organized by the reaction type of the electrochemical step and covers both oxidative and reductive reaction modes.

Influence of Solvents on the Oxidation Kinetics of Aldehydic Group Compounds by Diethylammonium Chloro-chromate

The redox studies of some compounds containing aldehydic functional groups by diethyl ammonium chloro-chromate (DEACC) in dimethyl sulfoxide leading a product forming to acid of correspondimg order. Reactions are found to be in unit order with oxidant while a fractional order (less than unity) was found w.r.t. reductants. The redox reactions are influenced with acid, the acid dependence is governed by this equation: kobs = a + b[H+].. When isomeric form of aldehyde, that is Me-CDO is oxidised with the same oxidant it was observed a considerable K.I.E. (Deuterium effect; kH/kD = 05.69 at 298 K). The reaction of Acetaldehyde was done in various non aqueous medium, soluble or miscible in DMSO. The effect of solvent is studied fitting our data in the solvent model of Taft's and Swain's applied for this purpose.. Rate constants are correlating very well with already reported Taft’s values of *; further the reaction constants are negative in nature. Suitable mechanism involving are proposed with transfer of hydride ion..

Magnetic Compton Scattering Study of Li-Rich Battery Materials

The redox process in a lithium-ion battery occurs when a conduction electron from the lithium anode is transferred to the redox orbital of the cathode. Understanding the nature of orbitals involved in anionic as well as cationic redox reactions is important for improving the capacity and energy density of Li-ion batteries. In this connection, we have obtained magnetic Compton profiles (MCPs) from the Li-rich cation-disordered rock-salt compound LixTi0.4Mn0.4O2 (LTMO). The MCPs, which involved the scattering of circularly polarized hard X-rays, are given by the momentum density of all the unpaired spins in the material. The net magnetic moment in the ground state can be extracted from the area under the MCP, along with a SQUID measurement. Our analysis gives insight into the role of Mn 3d magnetic electrons and O 2p holes in the magnetic redox properties of LTMO.

Exploring the relationships among stoichiometric coefficients, number of transferred electrons, mean oxidation number of carbons, and oxidative ratio in organic combustion reactions

Combustion reactions, stoichiometry, and redox reactions are some of the basic contents in chemistry curriculum. Although the counting of transferred electrons is critical in redox reactions, assigning mean oxidation number of organic carbons (ONc) is not always easy. Even though the relationship between the oxidative ratio (OR) and ONc is known, the relationship between the number of transferred electrons (Te−) and OR has not been thoroughly studied. The H-atom method has already been developed to balance and deduct organic combustion reactions. It can be used further to help establish the relationships among the stoichiometric coefficients (SC), the number of transferred hydrogens (TH), and Te−. This article uses the procedures of the H-atom method for balancing and deducting, and the known relationships among SC, TH, and Te− for exploring the relationships among SC, Te−, ONc, and OR in organic combustion reactions. By integrating three sets of relationships: (i) SC and Te−, (ii) Te− and ON, and (iii) SC and OR, the interconversions among SC, Te−, ONc, and OR can be mathematically formulated. Furthermore, Te−, ONc, and OR can be assigned by SC and the general molecular formula of CxHyOzXw.

Electrochemical Charge Storage Performance of Mesoporous MoO3@Co3O4 Nanocomposites as Electrode Materials

Constructing a novel nanocomposite structure based on Co3O4 is of the current interest to design and develop efficient electrochemical capacitors. The capacitive performance of MoO3@Co3O4 nanocomposite is compared with pristine Co3O4 nanoparticles, both of them being synthesized by hydrothermal technique. A BET surface area of ~41 m2g-1 (almost twice that of Co3O4 )and average pore size of 3.6 nm is found to be suitable for promoting Faradaic reactions in the nanocomposite. Electrochemical measurements conducted on both samples predict capacitive behavior with quasi-reversible redox reactions. MoO3@Co3O4 nanocomposite is capable of delivering a superior specific capacitance of 1248 Fg-1 at 0.5 Ag-1 along with notable stability of 92% even after 2000 cycles of charge-discharge and Coulombic efficiency approaching 100% at 10 Ag-1. The outstanding results obtained in this work assure functional adequacy of MoO3@Co3O4 nanocomposite in fabricating high-performance electrochemical capacitors.