VOC solvent

The VOC Solvents Directive. Sets fugitive emission limit values for the Volatile Organic Compounds in the paint (EU, 1999b). 

The most common method for cleaning the gun is to put a small amount of solvent into the pressure pot or cup gun, and clean the gun by spraying directly into the water curtain or dry filter of the spray booth. This is an unnecessary and expensive generation of waste. Both air emissions and waste paint are generated. In some states, notably California, regulations require that the paint operator spray gun cleaning solvents into a closed container so as to minimize VOC solvent emissions. This practice also allows recycling of the paint sprayed into the container (Joseph 1989). 

Amazing advances have been made, whereby reactions that are typically considered unsuited to the presence of moisture, e.g. Grignard-type chemistry, can be performed in water. Also, many reactions show enhanced rates compared with related reactions in VOC solvents. Although studies are still in progress, it has been proposed that some of these reactions are not actually taking place in water... 

RISK and Indoor Air Quality and Inhalation Exposure (IAQX) Indoor air mass balance with multiple sources and sinks Risk from inhalation exposure to VOCs, solvents, airborne particulate matter from indoor and outdoor sources Guo (2002)... 

Another advantage of using no solvent (or less solvent), is that reaction times are often shorter, especially when a ball mill or microwave reactor is used. It is likely that solvent free methods will become more widespread as the number of microwave reactors and ball mills in research laboratories increases. For the green chemist, it is also worth noting that significant efforts need to be made in greening the work up of many of the reactions presented here and elsewhere. In most cases, any VOC solvent readily available is used, when a less hazardous or bio-sourced VOC would be a better option. 

More recently, the hydrophobic effect has been used in its most extreme form, where the organic substrates are hydrophobic and insoluble such reactions are said to proceed on water .As can be seen in Figure 3.6, yields are significantly improved compared with the same reactions in VOC solvents and... 

Table 5.6 Comparison of solvent properties of 2-MeTHF with other VOC solvents. ...

Dietary habits can influence the TK and toxicity of solvents in several ways. The mere bulk of food in the stomach and intestine can inhibit systemic absorption of VOCs. Solvents in the GI tract partition into dietary lipids, largely remaining there until the lipids are emulsified and digested. This substantially delays the absorption of VOCs such as CCI4 and its hepatotoxicity. Increased incidences of cancer have been observed in obese humans possibly due to increase in liver CYP2E1 by ketone body formation. Caloric restriction has clearly been shown to reduce the incidence of cancer. Fasting results in increased P450 activities and reduced GSH, which affect the TK and toxicity of VOCs. Food may contain certain natural constituents, pesticides, and other chemicals, which may enhance or reduce the solvent metabolism. 

ATBC is used as a plasticizer for flexible films made of vinylchloride-vinylidene chloride copolymer and cellulose. It is used as a plasticizer in food contact applications and in vinyl toys for children (low toxicity). ATBC provides adherence to metals, low volatility, and resistance to yellowing. Also used in ink formulations, vinyl gloves, a non-VOC solvent in nitrocellulose propellants, a plasticizer in nail polishes, adhesives and coatings, and for coating both paperboard and foil. 

Figure 3. Vapor-liquid equilibrium for the VOC-solvent system.

Polyaromatic Mid-polar 635 545 Aromatic, therefore has different selectivity to 101, 102, Ci-C,o hydrocarbons, VOCs solvents, aldehydes... 

Carbon dioxide has also been successfully introduced into some dry-cleaning processes and various consumer formulations now no longer contain a VOC solvent. 

Reports of uncatalyzed reactions in liquid polymers continue to appear occasionally. For a recent example, a synthesis of homoallylic amines by a Barbier-type reaction in dried PPG [Eq. (1)] was recently reported by Andrews et al. [47]. Indium powder was used in stoichiometric quantities. The yields were comparable to those in VOC solvents. The products were isolated by vacuum distillation from the polymer, which was subsequently washed by water and dried by MgS04 before reuse. 

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