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Chlorinated Solvents and Solvent Stabilizers
Published in Thomas K.G. Mohr, William H. DiGuiseppi, Janet K. Anderson, James W. Hatton, Jeremy Bishop, Barrie Selcoe, William B. Kappleman, Environmental Investigation and Remediation, 2020
Solvent power is a measure of the solvent's effectiveness at dissolving oils, soldering flux, and buffing compounds. The most common test for judging changes to solvent power yields the Kauri-butanol value (KBV) (ASTM D 1133). The test uses Kauri gum,* which is very soluble in butanol but less soluble when butanol is diluted with a solvent that does not dissolve the resin. The test uses a burette, a flask, and a precision balance and provides a relative ranking of solvency. The solvent tested is added in small amounts until the solution becomes cloudy because of the precipitation of Kauri gum from the butanol solution. The more the solvent added before the solution becomes cloudy, the greater the solvent power and the higher the corresponding KBV. When tested as new solvent, uncontaminated by cleaning waste, water, or other impurities, the major chlorinated solvents have the following lower to higher order of solvent power and KBVs: PCE (KBV = 93) < methyl chloroform (KBV = 124) < TCE (KBV = 130) < dichloromethane (KBV = 178)* (Tarrer et al., 1989; Dow Chemical Company, 2002, 2006c; Solvay, 2002b). The solvent power of a solvent decreases with continued use and an increasing fraction of oily waste, grease, or soil.
Biodiesel as a non-aqueous medium for the synthesis of nanomaterials: relevance to metallic particulate suspensions in biofuels and their removal
Published in Biofuels, 2021
Rajpreet Kaur, Poonam Khullar, Anita Gupta, Gurinder Kaur Ahluwalia, Mandeep Singh Bakshi
Hydrocarbon fossil fuel is still a major source of energy in the modern world. Biodiesel is a well-known renewable fuel produced from vegetable oils and animal fats for its use in diesel vehicles [1–3]. One of the promising applications of biodiesel is as an industrial solvent [4,5] for use in industrial cleaning and degreasing, resin cleaning and removal of oil spills. It exhibits lower toxicity than most common solvents (e.g. toluene, methyl chlorides, etc.), and has a low volatile organic compound level and a high flash point. It is readily biodegradable and has excellent compatibility with other organic solvents, most plastics, and elastomers. It is an effective solvent due to its methyl ester component that considerably lowers its viscosity and increases its buoyancy compared with crude oil. Transesterified biodiesel comprises monoalkyl esters of long-chain fatty acids. They are also good non-aqueous solvents, but their solution behavior is rarely explored. Polymerization reaction of epoxidized methyl esters with phthalic anhydride is catalyzed by 2-methyl-imidazole in the presence of biodiesel, and biodiesel provides a good reaction medium at 180 °C [6,7]. A simple thermal treatment separates the biodiesel from the reaction products. The solvent strength is related to kauri-butanol value which is an international standardized measure of solvent power for a hydrocarbon solvent. Pure methyl esters have higher kauri-butanol values than those containing glycerides, and unsaturated fatty acid esters have higher kauri-butanol values than saturated fatty acid esters. Thus, the shorter the carbon chain of the fatty acid, the higher the kauri-butanol value of biodiesel. Biodiesel with a straight chain has a higher kauri-butanol value than biodiesel with a branched chain [5].