Nonconventional Energy Sources

Metallic copper efficiently catalyzes azide-alkyne cycloadditions under ultrasound or simultaneous ultrasound/microwave irradiation. Ultrasound favors mechanical depassivation in reactions involving metals and enhances both mass and electron transfer from the metal to the organic acceptor. It has been applied to accelerate the preparation of 1,2,3-triazole phthalimides via a 1,3-dipolar cycloaddition of phthalimidoethyl-azide [67]. 

Moreover, the combination of microwave and metals is possible if using well-dispersed fine metal particles in a polar high-boiling solvent [68]. 

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Nonconventional energy sources (e.g., microwaves, radiofrequency [RF], and induction)... 

A convenient and clean water-mediated synthesis of a series of 4-amino-2-ar-yl-1,2-dihydro pyrimido[l,2-a]benzimidazoles has been reported using alternative nonconventional energy sources [37]. The products were obtained in shorter times with excellent yields (78-89 %) from the multicomponent reaction of 2-ami-nobenzimidazole, malononitrile/ethylcyanoacetate, and carbonyl compounds (Scheme 8.26). The procedure does not involve the use of aity additional reagent/ catalyst, produces no waste, and represents a green synthetic protocol with high atom economy. The combination of microwave irradiation, ultrasonic irradiation, and aqueous-mediated conditions using multicomponent reactions leads to enhanced reaction rates, higher yields of pure products, easier workup, and sometimes selective conversions. Consequently, this protocol should be welcome in these environmentally aware days. 

A convenient and clean water-mediated synthesis of a series of indolo[l,2-c] quinazoline derivatives was reported using alternative nonconventional energy sources. The products are obtained in shorter times with excellent yields (78-89 %) from the MCR of 2-arrrinobenzimidazole, malononitrile, and carbonyl compourtds [55]. In their research, 2-(2-halophenyl)-lH-indoles arrd (aryl)methanamines were adopted as raw rrraterials to generate corresponding Schiff base via the Ullrrrarm reaction. Thert, gas as oxidarrt, 3 equiv K COj as base, and 10 mol% Cu(OAc)2 as catalyst were revealed as the optimum conditions to conduct aerobic oxidative C-H amination under solvent-free conditions or water (Scheme 13.14). 

The use of microwave irradiation (MWI) as a nonconventional source of energy, a consequence of converting electromagnetic energy, had become very attractive for its applications to chemistry and material processing. In organic synthesis, the potential... 

Petroleum displaced coal as the main source of energy in the world in 1965. Since that date, world petroleum consumption has doubled to the point where it now serves 50% of the world s energy demand. This rapid growth has been due to the ease with which petroleum can be discovered, produced, transported, and refined. However, it has been estimated that production of conventional petroleum will peak in a few decades, possibly by the year 2000. Although production of nonconventional sources of petroleum, such as tar sands, oil shales, and synthetic oil will increase, these sources will not make up the short-fall in supply. 

In mechanically- or hydraulically-rechargeable zinc-air batteries, zinc acts as an energy carrier [7]. The unique set of physical and electrochemical attributes of zinc has made it a long-lasting and widely used electrode material. The diversity and versatility by which zinc metal can be processed and used will allow zinc, in addition to its use in the many existing conventional battery systems, to be further explored and developed for nonconventional electrochemical power source and energy storage systems. 

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