Distillation solvents

Fig. 23(D) shows a simple distillation apparatus with an adaptor fitted to the lower end of the condenser. This apparatus can also be used for the recovery of solvents, or for the concentration of a solution with collection of the distilled solvent.

Maleic acid can be thermally dehydrated to maleic anhydride (69) or dehydrated through azeotropic distillation. Solvents such as xylenes (70) or dibutyl phthalate [84-74-2] (71) are preferred but conditions must be carefully adjusted to avoid isomerization to fumaric acid. 

Impurity to be removed Extractive distillation solvent Reference... 

Extraction and Extractive Distillation. The choice of an extraction or extractive distillation solvent depends upon its boiling point, polarity, thermal stabiUty, selectivity, aromatics capacity, and upon the feed aromatic content (see Extraction). Capacity, defined as the quantity of material that is extracted from the feed by a given quantity of solvent, must be balanced against selectivity, defined as the degree to which the solvent extracts the aromatics in the feed in preference to paraffins and other materials. Most high capacity solvents have low selectivity. The ultimate choice of solvent is deterrnined by economics. The most important extraction processes use either sulfolane or glycols as the polar extraction solvent. 

Essential Oils. Volatile oils from plants are referred to as essential oils. The oils can be obtained through steam distillation, solvent extraction, or separation of the oils from pressed fmit. They consist of oxygenated compounds, terpenes, and sesquiterpenes. The primary flavor components of essential oils are oxygenated compounds. Terpenes contain some flavors but are often removed from the essential oil because they are easily oxidized (causiag off-flavors or odors) and are iasoluble. Essential oils are prepared from fmits, herbs, roots, and spices. 

Extracts (petroleum), heavy naphthenic distillate solvent Extracts (petroleum), heavy paraffinic distillate solvent Extracts (petroleum), light naphthenic distillate solvent Extracts (petroleum), light paraffinic distillate solvent Extracts (petroleum), light vacuum gas oil solvent Euel oil no. 6... 

Figure 13.2 MDGC-ECD chromatograms of PCB fractions from sediment samples, demonstrating the separation of the enantiomers of (a) PCB 95, (b) PCB 132, and (c) PCB 149 non-labelled peaks were not identified. Reprinted from Journal of Chromatography, A 723, A. Glausch et al, Enantioselective analysis of chiral polyclilorinated biphenyls in sediment samples by multidimensional gas cliromatography-electi on-capture detection after steam distillation-solvent exti action and sulfur removal , pp. 399-404, copyright 1996, with permission from Elsevier Science.

In liquid-solid extraction (LSE) the analyte is extracted from the solid by a liquid, which is separated by filtration. Numerous extraction processes, representing various types and levels of energy, have been described steam distillation, simultaneous steam distillation-solvent extraction (SDE), passive hot solvent extraction, forced-flow leaching, (automated) Soxh-let extraction, shake-flask method, mechanically agitated reflux extraction, ultrasound-assisted extraction, y -ray-assisted extraction, microwave-assisted extraction (MAE), microwave-enhanced extraction (Soxwave ), microwave-assisted process (MAP ), gas-phase MAE, enhanced fluidity extraction, hot (subcritical) water extraction, supercritical fluid extraction (SFE), supercritical assisted liquid extraction, pressurised hot water extraction, enhanced solvent extraction (ESE ), solu-tion/precipitation, etc. The most successful systems are described in Sections 3.3.3-3.4.6. Other, less frequently... 

Figure 3.2 The three-step Soxhlet extraction process of the Soxtec extraction system (a) solubilisation of extractable matter from sample immersed in boiling solvent (b) rinsing of extracted solid and (c) concentration of extracted sample and collection of distilled solvent for reuse or disposal. Reproduced by permission of FOSS Analytical A/S, Hillerdd...

Applications Simultaneous steam distillation-solvent extraction has been in use for many years [163]. Steam distillation combined with continuous liquid extraction is an efficient technique for the removal and isolation of volatile compounds in various matrices (environmental,... 

Synonym(s) o-Tolyl phosphate TOCP TOTP Petroleum distillates solvent-refined light paraffinic Petroleum distillates, straight-run middle... 

Table III shows the results of operating the SRT unit in the hydrogen donor mode (catalytically hydrogenated solvent) with and without the addition of Light SRC to the distillate solvent Batch I solvent was used in Run 9 A blend of Batch VI solvent and Light SRC, 70/30 weight ratio, were catalytically hydrogenated as the feed to Runs 1 and 3 The hydrogen donor capability of the solvents were measured by the Equilibrium microautoclave tests These bench-scale SRT results are rather extraordinary in respect to increased distillate yields and improvement in unit operability with addition of Light SRC In Table III the integrated yields refer to the combination of liquefaction, CSD, and catalytic hydrogenation of the solvent ...

Richard, J. J., and Junk, G. A., Steam Distillation, Solvent Extraction, and Ion Exchange for Determining Polar Organics in Shale Process Waters. Anal. Chem, 1984. 56 pp. 1625-1628. 

Lacey, J.V., et al., Petroleum distillate solvents as risk factors for undifferentiated connective tissue disease (UCTD), Am. J. Epidemiol., 149, 761, 1999. 

Dimethylacetamide (DMAc), cellulose solvent (with lithium chloride), 5 384 N, N-Dimethylacetamide (DMAc), 23 703 extractive distillation solvent, 8 802 solvent for cotton, 8 21 N, AA-Dimethylacrylamide (DMA), 20 487 P,P-Dimethyl acrylic acid, physical properties, 5 35t Dimethylallylamine, 2 247... 

The dependence of the conductivity of this solution on the concentration and the temperature were studied during three days. The concentration was varied by distilling solvent out of the solution into a hanging burette, or into it from the burette. The resulting plots are shown in Figure 9. They are straight lines converging to a common intercept which represents the impurity contribution to the total conductivity. 

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