Solvent treating or extraction

Lube oil extraction plants often use phenol as solvent. Phenol is used because of its solvent power with a wide range of feed stocks and its ease of recovery. Phenol preferentially dissolves aromatic-type hydrocarbons from the feed stock and improves its oxidation stability and to some extent its color. Phenol extraction can be used over the entire viscosity range of lube distillates and deasphalted oils. The phenol solvent extraction separation is primarily by molecular type or composition. In order to accomplish a separation by solvent extraction, it is necessary that two liquid phases be present. In phenol solvent extraction of lubricating oils these two phases are an oil-rich phase and a phenol-rich phase. Tne oil-rich phase or raffinate solution consists of the "treated" oil from which undesirable naphthenic and aromatic components have been removed plus some dissolved phenol. The phenol-rich phase or extract solution consists mainly of the bulk of the phenol plus the undesirable components removed from the oil feed. The oil materials remaining... 

Often solvents do not extract 100% of the total radioactive residue. In this case, knowledge about the concentration of the target analyte(s) in the extract and the filter cake is necessary. Even if large amounts of radioactivity remain in the solid residual materials, the extraction efficiency may be sufficient if this unextracted radioactivity is permanently bound to the matrix or if it is associated with compounds which are not included in the residue definition. Finally, in all cases a well performed metabolism study can provide the answers needed, even where residues in the edible parts of treated crops or animals do not occur. If incurred residues do not occur, clearly the determination of extraction efficiency is not required. 

Elemental sulfur is present in most soils and sediments (especially anaerobic), and is sufficiently soluble in most common organic solvents that the extract should be treated to remove it prior to analysis by ECD-GC or GC-MS. The most effective methods available are (1) reaction with mercury or a mercury amalgam [466] to form mercury sulfide (2) reaction with copper to form copper sulfide or (3) reaction with sodium sulfite in tetrabutyl ammonium hydroxide (Jensen s reagent) [490]. Removal of sulfur with mercury or copper requires the metal surface to be clean and reactive. For small amounts of sulfur, it is possible to include the metal in a clean-up column. However, if the metal surface becomes covered with sulfide, the reaction will cease and it needs to be cleaned with dilute nitric acid. For larger amounts of sulfur, it is more effective to shake the extract with Jensen s reagent [478]. 

FIGURE 12.2 Responses of beavers to predator chemicals applied to aspen sticks. Activity periods were consecutive 5 days of experiment in two areas in New York and the percentages of sticks consumed is the mean of several replications of the experiment. All treated sticks were punctured to improve the uptake of chemicals intact sticks were untreated (A), punctured but not treated ( ), punctured and treated with the solvent methanol ( ) (the three controls), or treated with extracts from other animals. Treatments that inhibited consumption most were excrement extracts from lynx (+) and coyote ( ... ), both sympatric predators (lynx now extirpated). Beavers accepted most readily the three control sets. Other chemicals were from otter (o), wolf ( - ), lion ( ). (From Engelhart and Miiller-Schwarze,... 

Analytical techniques to evaluate potential lubricating oil stocks are essential to a refiner s planning program. When sulfuric acid was the sole chemical used to refine burning oils and lubricants, it was a simple matter to carry out acid-treating experiments on a small scale in the laboratory, and results so obtained were quite reliable. With the advent of solvent treating, analytical techniques were developed which consisted of single or multiple-batch laboratory extractions in conjunction with correlations based on plant experience (17). 

Method 3(when acardite II centralites are present) a)Extract with chlf or methylene chloride ca lOg of finely divided propellant, evap the solvent and weigh the dried extract (wt 1 - centralite + acardite II) b)Treat the extracted material with aq AcOH at pH ca 4 and filter the mixt through cared sintered glass crucible. Rinse the residue, dry it to const wt and weigh(wt 2 = acardite II and wt 1 — wt 2 centralites) c)Continue. the analysis as described in procedures (c) to (g) of Method 4... 

Nonaqueous Liquid Wastes Protocol. Nonaqueous liquid wastes were defined to include samples that range from water-soluble organic liquids to immiscible oils. Only a limited amount of data are available on the applicability of this protocol (Figure 4) to compounds other than oils or petroleum products. This medium differs from other environmental media because mutagenic materials are often concentrated in organic liquids. Therefore, this protocol incorporates dilution steps rather than the concentration techniques used in the other media protocols. This protocol is also unique because of the opportunity to test neat samples or samples diluted with DMSO rather than sample components isolated with an absorbent or extracted with a solvent. For this reason, samples treated with this protocol should contain polar compounds and/or volatile compounds that would be lost when the other protocols are used. 

A liquid-liquid extraction process produces a solvent-rich stream called the extract that contains a portion of the feed and an extracted-feed stream called the raffinate. A commercial process almost always includes two or more auxiliary operations in adcfition to the extraction operation itself. These extra operations are needed to treat the extract and raffinate streams for the purposes of isolating a desired product, recovering the solvent for recycle to the extractor, and purging unwanted components from the process. A typical process includes two or more distillation operations in addition to extraction. 

In liquid extraction, sometimes called solvent extraction, a mixture of two components is treated by a solvent that preferentially dissolves one or more of the components in the mixture. The mixture so treated is called the raffinate and the solvent-rich phase is called the extract. The component transferred from raffinate to extract is the solute, and the eomponent left behind in the raffinate is the diluent. The solvent in the extract leaving the extractor is usually recovered and reused. In extraction of solids, or leaching, soluble material is dissolved from its mixture with an inert solid by means of a liquid solvent. The dissolved material, or solute, can then be recovered by crystallization or evaporation. Crystallization is used to obtain materials in attractive and uniform crystals of good purity, separating a solute from a melt or a solution and leaving impurities behind. 

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