Molecular energy storage reactions

The conversion of molecular nitrogen to ammonia constitutes a potentially useful energy-storage reaction utilizing abundant raw material. The interaction of molecular dinitrogen with metal centers has been studied in considerable depth. It has been shown that N2 can be bound and reduced to NH3 at Mo, W, V, or Fe centers, particularly where these metals are in a low oxidation state and have a tertiary phosphine environment.312... 

From the standpoint of thermodynamics, the essential quantity which governs the course of a chemical reaction is the chemical potential of the system or, in the case of interest, the free energy storage within the molecular coil. This quantity, unfortunately, is difficult to evaluate in non-steady flow. At modest extension ratios (X < 4), the free energy storage of a freely-jointed bead-spring chain is... 

J. O M. Bockrls. S.U.M. Khan, Surface Electrochemistry a Molecular Level Approach, Plenum (1993). (Quantum features, photo reactions, bio-electrochemistry, energy storage and other topics.)... 

As will be evident from this chapter, there is a significant body of work on electron-transfer (ET) reactions in porous materials driven by both fundamental research interests and applications in diverse areas such as sensors, catalysis and photochemical energy storage. Porous materials offer unique opportunities for ET reactions for several reasons. Porosity at the level of molecular size allows for novel spatial arrangements of molecules. Steric and electrostatic constraints can alter... 

In photochemical processes for solar energy storage, photon absorption either creates a molecular excited state or stimulates an interband electronic transition in a semiconductor, which induces a molecular change. Comprehensive reviews, including those by Gratzel (1980), Kalyanasundaram (1982) and Harriman (1986-7), have discussed various aspects of photochemical energy conversion. A photoactivated molecular excited state can drive either i) photodissociation ii) photoisomerisation or iii) photoredox reactions. Processes based on semiconductors may involve photovoltaic or photoelectrochemical systems. 

Thermochemical energy storage relies on the energy absorbed and released in breaking and reforming molecular bonds in a completely reversible chanical reaction, where a, is the fractioned reacted, m is the mass, and Ah is the endothermic heat of reaction. 

Purely viscous forces, unless augmented by other mechanisms, are not a dominant contributor to mechanochemical reactions. Inevitably, strains are necessary to provide sufficient energy storage within molecular bonds to induce bond rupture. In melts and concentrated solutions, the entanglement network can provide the elastic strains for mechanochemical reactions. In solid-state mechanochemistry, surfaces, friction, and cleavage planes are considered to be loci of such reaction sites. 

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