Soxhlet extraction apparatus

Conventional methods of polymer extraction use large quantities of solvents as in shake-flask extraction or a Soxhlet extraction apparatus. For all classical extraction methods, solvent selectivity, in general, is low, i.e. solvents with high capacity tend to have low selectivity. In reflux extractions, which are still quite popular in polymer applications, the polymer is refluxed with a hot solvent, which disperses it to provide a solvent phase containing additives. In these conditions solvents are at their atmospheric boiling point. These methods are lengthy and labour intensive. Fractional extraction is based on solvents with increasing solvent power (cf. also [81]). 

Sand and polymer characterization. The oil sands were extracted in a Soxhlet extraction apparatus with toluene as the refluxing liquid. After the extr-... 

A mixture of rhodium II) acetate (228 mg, 0.516 mmol), the imidazolidinone (1.70 g, 6.15 mmol), and dry chlorobenzene (20 mL) is heated under reflux for 18 h in a flask fitted with a Soxhlet extraction apparatus into which a thimble is placed containing an oven-dried mixture of sodium carbonate and sand (2 1, 5 g). The progress of the ligand-exchange reaction can be monitored by HPLC (p-Bondapak-CN column, methanol). The resulting blue solution is concentrated under reduced pressure, and the residue is purified by column chromatography (reversed phase silica, Bakerbond Cyano 40 mm prep. LC packing, methanol). 

For the continuous extraction of a solid by a hot solvent, the Soxhlet extraction apparatus, shown in Fig. II, 44, 4, is usually employed. The... 

The thimbles were treated in the Soxhlet extraction apparatus using benzene. The residue left in the thimbles was dried and carefully weighed. A total of 12% coal was extracted in this manner. These three coal samples were extracted with fresh tetralin at reaction temperatures of 400°, 420°, and 440°C. 

Camphorsultam. A dry, 2-L, three-necked, round-bottomed flask is equipped with a 1.5-in egg-shaped Teflon stirring bar, a 250-mL addition funnel, and a 300-mL Soxhlet extraction apparatus equipped with a mineral oil bubbler connected to an inert gas source. The flask is charged with 600 mL of dry tetrahydrofuran (THF) (Note 1) and 6.2 g (0.16 mol) of lithium aluminum hydride (Note 2). Into the 50-mL Soxhlet extraction thimble is placed 35.0 g (0.16 mol) of (-)-(camphorsulfonyl)imine (Note 3) and the reaction mixture is stirred and heated at reflux. After all of the (camphorsulfonyl)imine has been siphoned into the reaction flask (3-4 hr), the mixture is allowed to cool to room temperature. The unreacted lithium aluminum hydride is cautiously hydrolyzed by dropwise addition of 200 mL of 1 N hydrochloric acid via the addition funnel (Note 4). After the hydrolysis is complete the contents of the flask are transferred to a 1-L separatory funnel, the lower, silver-colored aqueous layer is separated, and the upper layer placed in a 1-L Erlenmeyer flask. The aqueous phase... 

For the continuous extraction of a solid by a hot solvent, it is better to use a Soxhlet extraction apparatus such as that shown in Fig. 2.96. The solid substance is placed in the porous thimble A (made of tough filter paper) and the latter is placed in the inner tube of the Soxhlet apparatus. The apparatus is then fitted to a round-bottomed flask C of appropriate size containing the solvent and boiling chips, and to a reflux condenser D (preferably of the double surface type). The solvent is boiled gently the vapour passes up through the tube E, is condensed by the condenser D, and the condensed solvent falls into the thimble A and slowly fills the body of the Soxhlet. When the solvent reaches the top of... 

The carboxin is extracted from the sample with acetone in a Soxhlet extraction apparatus and, after concentration of the extract, is determined via gas-liquid chromatography using a nitrogen-selective detector. The presence of carboxin is confirmed by the use of a sulfur flame photometric detector. Recoveries ranged from 73 to 80% (barley) and 73 to 78% (wheat). 

The total nitrogen of the substrate was determined following the standard Kjeldahl method (8). The oil content of the cake was determined by gravimetry after extraction of the samples with n-hexane using a Soxhlet extraction apparatus (8). 

The hydrogen sulfate was dissolved in water and the pH of the solution was adjusted to 5.6 (pH-meter) with 0.1 N sodium hydroxide solution. The water solution was evaporated to dryness and the residue dried with absolute ethanol/benzene and once more evaporated to dryness. The remaining crystal mixture was extracted in a Soxhlet extraction apparatus with absolute methanol. From the methanol phase the sulfate of l-(3, 5 -dihydroxyphenyl)-2-(t-butylamino)-ethanol crystallized. Melting point 246°C to 248°C. 

A micro Soxhlet extraction apparatus (Ace Glass, Inc.) consisting of the extractor, a 50-mL round-bottomed flask, and an Allihn condenser fitted with a 10 x 50 mm thimble is used. 

A mixture of 1 g. of zinc dust and 20 g. (0.13 mol) of anhydrous chromium(III) chloride is placed in the thimble of a Soxhlet extraction apparatus. Approximately 218 ml. (2.7 mols) of tetrahydrofuran (freshly distilled from calcium hydride) is placed in a 300-ml. round-bottomed flask and attached to the extraction apparatus a calcium chloride drying tube is fitted to the reflux condenser. At the end of 4 hours of reflux the reaction is stopped and an additional gram of zinc dust is placed in the thimble. The reflux is then resumed and continued for 8 hours (or until the recycling liquid is colorless). The tetrahydrofuran solution... 

The crude product is isolated and initially purified by removal of solvent by rotary evaporation followed by extraction with three small washes of THF (3 X 10 mL) to remove the extremely soluble by-product, K[Lu(CgHg)2]. Final purification and removal of KCl are achieved by transfer of the crude product (- 4.3g) to a Kontes Schlenk Soxhlet extraction apparatus. The apparatus is removed from the dry box and the residue is extracted with THF (60 mL) over a 24-h period on a Schlenk line under argon. During extraction, the pure white product precipitates in the Soxhlet receiver flask. It is isolated in 50% yield (1.73 g) by vacuum filtration in the dry box. Cooling of the light yellow filtrate to — 40 °C does not yield additional microcrystalline product. In practice, it is normally discarded (by removal from the dry box and careful quenching with 2-propanol) since it contains K[Lu(CgHg)2], which has not been removed by the previous purification step. 

Hydrocarbon Analysis. Sediment samples were thawed and mixed to provide a homogeneous sample. Approximately 150 g wet weight was placed in a Soxhlet extraction apparatus and saponified-extracted with benzene /0.5 N KOH-methanol (50/50) (ca. 250 ml total) for 24 hours, or until the extraction solution was clear (6,11,12). An internal standard consisting of ca. 50 ug each of 5,a-androstane and o-terphenyl was added prior to extraction to provide assurance of extraction efficiency, separation of saturated and unsaturated fractions and to provide a standard reference for the gas chromatographic data system. Methylstearate (the methyl ester of stearic acid) was added to select samples to verify saponification efficiency. 

Samples of 1 gram of dried primary and dried wasted sludge were extracted in a Soxhlet extraction apparatus with 150 ml methanol for 4 hours. An aliquot of the methanol extract (20 ml out of a total volume of 200 ml) was passed over a small anion exchange column. The column was washed with 10 ml methanol before elution of the LAS with 3 ml of acidic methanol. The effluent was diluted to about 70 ml with water and the pH was adjusted to a value of 7. The solution was then brought to a value of 100 ml and an aliquot of 25 ml was passed over an octadecyl reversed phase SPE column. The sample was further treated as described above. The samples were kept in a dry state until analysis by HPLC. Prior to HPLC, the residues were dissolved in an acetonitrile/water 70/30 solvent mixture. 

Soxhlet extraction is used as the benchmark against which any new extraction technique is compared. The basic Soxhlet extraction apparatus consists of a solvent reservoir, an extraction body, a heat source (e.g. an isomantle) and a water-cooled reflux condenser (Figure 7.2). A Soxhlet uses a range of organic solvents to remove organic compounds, primarily from solid matrices. The solid sample (ca. 10 g if a soil) and a similar mass of anhydrous sodium sulfate are placed in the porous thimble (cellulose), which in turn is located in the inner tube of the Soxhlet apparatus. The apparatus is then fitted to a round-bottomed flask... 

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