Oxidative green” solvent

Lo, W.-H., Yang, H.-Y., Wei, G.-T., One-pot desulfurization of light oils by chemical oxidation and solvent extraction with room temperature ionic liquids. Green Chem., 5, 639-642, 2003. 

Examples of organic reactions in green solvents abound. One example is described in the oxidation of cyclohexenes with 30% hydrogen peroxide (Sato et al., 1998). Cur-rendy, the industrial production of adipic acid uses nitric acid oxidation of cyclohexa-... 

Potentially, supercritical carbon dioxide (SCCO2) is the ideal green solvent. It is non-toxic for both humans and the environment. It is chemically inert under most conditions, whether they be non-flammable or non-protic, and it is inert to radical and oxidizing conditions. This gas can be obtained in large quantities as a by-product of fermentation, combustion, and ammonia synthesis and it is relatively cheap, particularly compared with conventional solvents. Supercritical carbon dioxide presents other practical advantages as well, such as the possibility of achieving product isolation to total dryness by simple evaporation. 

Especially, the eco-friendly ionic liquids have obtained extensive attention in organic synthesis with the merits provided as above. The ionic liquids as the unusual green solvents are applied extensively in various organic synthesis reactions, such as Friedel-Crafts reactions, oxidation reactions, reduction reactions, addition reactions, C-C formation reactions, nucleophilic substitution reactions, esterifications, rearrangements, hydroformylations, and nitration reactions [7-14]. Besides, the ionic liquids also have applications in the extraction separation, the electrochemistry, and preparation of nanostructured materials, the production of clean fuel, environmental science, and biocatalysis. This chapter would present in detail the application of the ionic liquids as the unusual green solvents (also as dual green solvent and catalyst) for the alkylation and acylation. 

Abstract Ionic liquids as green solvents have shown important application in extraction and separation of metals. In this chapter, the new application perspective and the important fundamental and applied studies of the extraction and separation of metals in ionic liquids which include metal oxide processing, mineral processing, electrodeposition of metals (especially reactive metals such as Al, Mg, and Ti), and extraction of metal ions are presented. 

Preliminary studies have shown that ionic liquids have potential as solvents and electrolytes for metal recovery, and the feasibility of these solvents has been demonstrated for the extraction of gold and silver from a mineral matrix [7], the recovery of uranium and plutonium from spent nuclear fuel [8], and the electrodeposition and electrowinning of metals (especially, for active metals such as Li, Na, Al, Mg, and Ti) from ionic liquids [9-11], Ionic liquids as green solvents and electrolytes have shown important and potential application in extraction and separation of metals. In this chapter, the new applications and the important fundamental and appUed studies on the extraction and separation of metal in ionic liquids including metal oxides and minerals or ores processing, electrodeposition of metals (mainly for active metals), and extraction and separation of metal ions are described. 

Ionic Liquids as Green Solvents for the Oxidation of Alcohols... 

From an economic and environmental perspective, catalytic aerobic alcohol oxidation represents a promising protocol. The use of molecular oxygen as the primary oxidant has several benefits, including low cost, improved safety, abundance, and water as the sole by-product. In this way, many catalytic systems have been used for the aerobic oxidations in ionic hquids as green solvents. Different types of catalysts or catalytic systems useful for the oxidation of alcohols with as terminal oxidant in ionic liquids as solvent will be discussed below. 

Jain SL, Sharma VB, Sain B (2006) Methyltrioxorhenium and sodium bromide-catalyzed oxidation of alcohols to carbonyl compounds with using l-butyl-3-methylimidazolium tetrafluo-roborate ionic liquid as a novel recyclable green solvent. Bull Chem Soc Jpn 79 1601-1603... 

Boschetti A, Montagnaro F, Rienzo C, Santoro L (2007) A preliminary investigation on the use of organic ionic liquids as green solvents for acylation and oxidation reaction. J Qeaner Prod 15 1797-1805... 

Yadav JS, Reddy BVS, Basak AK, Narsaiah AV (2004) Recyclable 2nd generation ionic liquids as green solvents for the oxidation of alcohols with hypervalent iodine reagents. Tetrahedron 60 2131-2135... 

Chapter 14 describes the methods of oxidation of alcohols using different types of oxidizing agents and/or systems using ionic hquids as green solvents. 

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