Volatile nonpolar organic chemicals

Analytical Methods for the Determination of Volatile Nonpolar Organic Chemicals in Water and Water-Related Environments... 

Dichloromethane is a volatile liquid with excellent solvent properties for nonpolar organic solutes. It has been used as a solvent for the decaffeination of coffee, in paint strippers, as a blowing agent in urethane polymer manufacture, and to depress vapor pressure in aerosol formulations. Once commonly sold as a solvent and stain remover, highly toxic carbon tetrachloride is now largely restricted to uses as a chemical intermediate under controlled conditions, primarily to manufacture... 

Salmona et al. [66] used El and CIMS to identify benzothiazole derivatives leached into injections by rubber plunger seals from disposable syringes. One of the compounds was used as a rubber vulcanisation accelerator, and four others were formed during syringe sterilisation with ethylene oxide. Applications of hyphenated chemical impact mass-spectrometric techniques are described elsewhere GC-MS (Section 7.3.1.2), for polar and nonpolar volatile organics, SFC-MS (Section 13.2.2) and TLC-MS (Section 7.3.5.4). 

All aqueous/scC02 systems discussed up to now use C02 as the phase for substrates and products. Naturally, this restricts the applications to relatively nonpolar and/or volatile components with sufficient solubility in the supercritical medium. Intriguing alternatives for processing highly polar substrates are inverted aqueous systems. In this approach, a C02-philic catalyst resides in the nonpolar COz phase and the water-soluble substrates and products are contained in the aqueous layer. The product stream of these systems is obtained without the need for depressurization of the COz phase, which is an important cost factor in SCF processing. Furthermore, the aqueous solution is not contaminated with any organic solvent or catalyst residues, which is particularly important if the product is a fine chemical for direct further use in aqueous solution. 

ILs are able to dissolve some nonpolar molecnles as well as some very polar ones. They have negligible vapor pressnre and excellent thermal stabilities, can act as green solvents, and replace volatile organic solvents in several chemical reactions. Their physicochemical properties [12] can be modified by changing the cation, anion, or substituent (R-gronps) hence, ILs can be nsed not only as reaction solvents but also as catalysts or catalytic solvents. ILs have also been referred to as designer solvents [13] as their physical and chemical properties snch as solubility, density, refractive index, and viscosity can be adjnsted by a careful choice of cation, anion, or both [14-16]. 

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