Percent solvent extractables

Figure 5. RTV silicone percent solvent extractables in Freon TA.

Plutonium Purification Using Solvent Extraction. The Hanford Plutonium Reclamation Facility (PRF) uses a 20 percent TBP-CClt, solution to extract Pu(IV) from HNO3-HF-AI(NO3)3 solutions of dissolved scrap. The final product solution from the... 

Percent extraction as the term implies provides directly a measure of effectiveness a solvent or a strippant used in solvent extraction. The mathematical expression of percent extraction is quite simple to derive simply from elementary considerations. This fact, therefore, spares the need to deduce. The expression for percent extraction, P, is shown as ... 

Kirschner et al. [358] have observed a lower percent finish-on-yarn (FOY) for SFE as compared to solvent extraction of various fibre/textile matrices. This is rationalised as organic solvents tend to extract components from a matrix more vigorously than scCC>2 and thus remove more of the oligomer and organic components present in the fibre. SFE is a potentially softer extraction technique since it removes less of the polymer from the fibre matrix than liquid solvent extraction. 

Acid hydrolysis of the polysaccharide portion of wood will release lignin but also causes major condensation reactions in the product(2l). These reactions can be minimized by using 41 wt. percent hydrochloric acid in place of other mineral acids but some condensation reactions still occur(22). This is not an effective method by which to obtain unaltered lignin. On the other hand, lignin can be solvent extracted from wood at temperature of 175°C using solvent mixtures such as 50/50 by volume water/1,4-dioxacyclohexane(23) Changes in lignin under these conditions appear to be minor. 

Dapex [Di-alkylphosphoric acid extraction] A process for the solvent extraction of uranium from sulfuric acid solutions using di-(2-ethylhexyl) phosphoric acid (HDEHP). The HDEHP is dissolved in kerosene containing 4 percent of tributyl phosphate. The uranium is stripped from the organic phase by aqueous sodium carbonate and precipitated as uranyl peroxide (yellow cake). The process was no longer in use in 1988. See also Amex. 

Table 6 Inhibition of Cytochrome P450 3A4—Mediated Metabolism by Sequential Solvent Extracts of a Commercially Available Product and Fresh Garlic (n > 6 Mean Percent Inhibition SD)...

Solvent Extraction. The yields of extracts and extraction residues obtained by successive hexane, toluene and THF extraction of the floated coal samples, plus the percent of the total of the organic sulfur that each extract contained are shown in Table II. 

Other sources of benzene include processes for steam cracking heavy naphtha or light hydrocarbons such as propane or butane to produce a liquid product (pyrolysis gasoline) rich in aromatics that contains up to about 65 percent aromatics, about 50 percent of which is benzene. Benzene can be recovered by solvent extraction and subsequent distillation. 

The SRC-11 liquid, boiling range of 453-665 K, was fractionated by solvent extraction based on its solubility in n-pentane. The pentane-soluble oil fraction (A) 99.3% of SRC-II, was further fractionated by sequential treatment with anion-exchange resin, cation-exchange resin and silica-gel column, as illustrated in Figure 1. Weight percent yields of the fractions, relative to A are included in Figure 1. 

Sonication with a waterD methanol solution is the most popular method for the extraction of As species from rice powder [24, 25], algae, chicken meat [26], oyster tissue [27, 28], and baby foods [29]. Sample treatment with triBuoroacetic acid at 100°C was reported to be an efficient method for the extraction of As species present in different food matrices when compared with alternative methods that included sonication and accelerated solvent extraction. Extraction recoveries from 94 to 128 percent were obtained [29]. Low-molecular-weight Se compounds were extracted from nuts with HCIO4 to produce a fraction containing 3 to 15 percent of the total Se in different types of nuts [30]. 

The use of methanol and ethanol, two solvents that can be well mixed with water, should be discussed separately, as they are used for several types of sample preparation on the basis of similar expected effects, but for different purposes. The feature common to both solvents is the observation that most of the sample proteins precipitate when the concentration of these compounds exceeds ca. 40 percent (v/v), thus enabling the analyst to separate the protein fraction by centrifugation or microfiltration. This way, either the proteins not intended for further analysis (e.g., enzymes or proteins that were inadequately hydrolyzed) can be removed [62], or, the purification of Se-containing proteins by successive solvent extractions can be achieved [12]. At concentrations of less than 40 percent (v/v), both methanol and ethanol are usually mixed with 0.1 moll-1 HC1 however, the use of these mixtures entails a relatively low extraction efficiency of Se (10-14 percent). Therefore, they are intended only for the extraction of water-soluble Se species, generally free selenoamino acids [15, 21, 63, 64]. 

Solvent Extraction. The yellow cake is dissolved in nitric acid and extracted from this aqueous phase by 5 percent tributyl phosphate (TBP) in a hydrocarbon diluent. The diluent reduces the density and viscosity of the TBP, enhancing the aqueous/solvent phase separation. The extraction is very specific for uranium, with separation factors of 103 to 105. The product thus obtained is an aqueous uranyl nitrate solution (Fig. 21.14). 

Increases in yield of naval stores are brought about by chemical treatment of the exposed wood, especially with paraquat herbicides (dipyridyl compounds). This treatment stimulates extensive oleoresin formation and diffusion into the wood, extending to the pith of the tree and several feet above the treatment level. As much as 40 percent oleoresin content in the wood has been produced. Such treatment could double naval stores production, for both gum and sulfate processes. It also has the potential of providing a new type of wood naval stores by solvent extraction prior to kraft pulping, or a combination of both methods. 

Fatty Acids. Of the total fatty acids produced annually in the United States, amounting to more than 450,000 tons, 35 percent come from tall oil. The solvent extraction of pine wood yields only 1 percent fatty acids and their esters. The yield is not increased, however, by paraquat (dipyridyl herbicides) treatment. Hence, the kraft-pulping industry will continue to be the major source of fatty acids from wood. The approximate distribution of uses of the fatty acids are ... 

Introduction of the expander, a high-shear extruder with an interrupted-flight screw, in the mid-1980s revolutionized oilseed extraction practices. Essentially all solvent-extracted cottonseed, and approximately 70 percent of domestic soybean tonnage now are processed... 

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