Separation Solvent filtration

The solid is separated by filtration and the filtrate is extracted with three 150-ml. portions of ether. Caution Gloves should be worn when handling this solution because of the large amount of cyanide it contains.) The solid is dissolved in ether and this solution is combined with the extracts. The combined ethereal solutions are washed with water and dried over 5 g. of sodium sulfate. Removal of the solvent by distillation leaves crude ferrocenyl-acetonitrile as a solid or as an oil that crystalli/.es on being scratched. I he nitrile is dissolved in about 200 ml. of boiling... 

A solution or dispersion consisting of 20.1 g (0.1 mol) of 7-chloro-p-fluorobutyrophenone, 19.8 g (0.2 mol) of 4-methylpiperidine end 0.1 g of potassium iodide in 150 ml toluene is heated in a seeled gless tube for 15 hours at 100°C to 110°C. The potassium iodide and the 4-methylpiperidine hydrochloride formed in the reaction are separated by filtration and the solvent removed from the filtrate by evaporation In vacuum on a steam bath. The residue is distilled and the fraction obtained at 120°C to 125 0 and at a pressure lower than 0.1 mm Hg is collected. The basa Is dissolved in ether and the 4-fluoro-7-(4-methylpiperidino)-butyro-phenone precipitated as the hydrochloride. The reaction product is purified by recrystallization in ethanol/ether. 

A mixture of 1.44 g. (0.0099 mole) of indole-3-carboxaldehyde,2 7.0 g. (0.053 mole) of diammonium hydrogen phosphate, 30 g. (30 ml., 0.34 mole) of 1-nitropropane, and 10 ml. of glacial acetic acid is refluxed for 12.5 hours. During the reflux period the pale-yellow mixture becomes dark red. The volatile reactants and solvent are removed under reduced pressure, and an excess of water is then added to the dark residue. After a short time, crude indole-3-carbonitrile precipitates rapidly. It is separated by filtration and dried under reduced pressure weight 1.20-1.34 g. (85-95%). Crystallization from acetone-hexane, with decoloriza-tion by activated carbon, yields 0.68-0.89 g. (48-63%) of fairly pure indole-3-carbonitrile, m.p. 179.5-182.5° (Note 1). 

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... 

DPSU is a rather weak silylating agent, which has found use for silylation of the hydroxy group. The advantage of this reagent is that it does not give by-products of silylation in solution because /V,/V -diphenylurea is insoluble in most organic solvents and can be almost completely separated by filtration. 

The polymer supported HFe(CO)4 ion (33 mmol), prepared according to procedure 8.4.3, is stirred with the haloalkane (ll mmol) in THF (50 ml) for 4 h at room temperature. The resin is separated by filtration and the solvent is evaporated under reduced pressure to yield the alkane. 

Organyltellurium trichlorides (general procedure) A solution of the ditelluride in benzene or CCI4 is treated dropwise at 0°C with a slight excess of SO2CI2 in the same solvent. The crude precipitate of the trichloride is separated by filtration. The yield is close to 100%. 

The physical properties of dendrimers such as solubility, arising from their hyperbranched globular shapes and the peripheral groups, can be modified by end-group modification. In core-functionalized dendrimers, the immiscibility of the wedges with a solvent enables precipitation and subsequent separation by filtration. 

The advantage of the above-described catalytic procedures is the possibility of preparing large amounts of hydrofullerenes that can be synthesized selectively (depending on the metal). Compared with other hydrogenations, the products can easily be separated by filtration of the catalyst and evaporation of the solvent [73]. 

The purification of bacterial constituents usually starts in a very conventional way with an extraction step of the crude broth at neutral or slightly acidic pH. Mycelium-forming organisms are separated by filtration, and the cell mass and the filtrate are extracted separately. For the liquid phase, adsorber resins allow high recovery rates of metabolites and low process costs due to repeated use of the resins. If liquid-liquid extraction has to be applied, medium or highly polar solvents are favored. Ethyl acetate is the solvent of choice, and only in few cases is butanol superior. To extract the moist cell material, ethyl acetate, acetone or dichloromethane/methanol can be used. 

A 100-mL round-bottomed flask containing a Teflon-coated magnetic stirring bar is charged with a solution of 0.69 g (1.5 mmol) of (pentafluorophenyl)(tetrahydrothiophene)gold(I) in 30 mL of ethanol 0.58 g (1.5 mmol) of (benzyl)triphenylphosphonium chloride (from Fluka AG) is added and the mixture is stirred at room temperature for 1 h. Concentration of the solution by removal of 20 mL of solvent under reduced pressure and cooling to 0 °C results in a white precipitate. This is separated by filtration and washed with two 5mL portions of hexane. Yield 0.94 g (83%). 

Solvent-Refined Coal Process. In the 1920s the anthracene oil fraction recovered from pyrolysis, or coking, of coal was utilized to extract 35—40% of bituminous coals at low pressures for the purpose of manufacturing low cost newspaper inks (113). Tetralin was found to have higher solvent power for coals, and the I. G. Farben Pott-Broche process (114) was developed, wherein a mixture of cresol and tetralin was used to dissolve ca 75% of brown coals at 13.8 MPa (2000 psi) and 427°C. The extract was filtered, and the filtrate vacuum distilled. The overhead was distilled a second time at atmospheric pressure to separate solvent, which was recycled to extraction, and a heavier liquid, which was sent to hydrogenation. The bottoms product from vacuum distillation, or solvent-extracted coal, was carbonized to produce electrode carbon. Filter cake from the filters was coked in rotary kilns for tar and oil recovery. A variety of liquid products were obtained from the solvent extraction-hydrogenation system (113). A similar process was employed in Japan during Wodd War II to produce electrode coke, asphalt (qv), and carbonized fuel briquettes (115). 

Solid foods can be extracted by means of partition into organic solvents (133). The samples are macerated with aqueous acetone, methanol, or ethanol. The extract is made alkaline with sodium tetraborate, and the solids are separated by filtration or centrifugation after the addition of Celite 545 (135). Foods can also be ground with Celite and 0.1 N hydrochloric acid and washed with chloroform (156). 

The flask is cooled to room temperature, all solvents are allowed to drain from the column, and 120-150 g. of colorless product, m.p. 99-101°, is separated by filtration and washed with petroleum ether. A second crop, weight 25-40g., m.p. 98.5-101.0°, is obtained by concentrating the combined filtrates to about 250 ml. and cooling the concentrate to room temperature. The crops of 10-methyl-10,9-borazarophenanthrene are combined weight 155-182 g. (54-65% based on 2-aminobiphenyl). The product is sufficiently pure for many purposes. A purer product, m.p. 103-104°,2 may be obtained by recrystallization from petroleum ether (b.p. 35°) (Note 12). 

Ail equimolar mixture (10 mmol) of benzylidenemethylamine 1 (1.19 g) and acetylacetone 2a (1 g) was adsorbed onto montmorillonite K10 (5 g) and allowed to stand at room temperature for 3 days. The mixture was extracted with CH2C12, the clay separated by filtration and the solvent evaporated under reduced pressure. Pure compound 3 could be isolated by short-path distillation (81% yield). The equimolar mixture of enamino ketone 3 and alkene 4a (5 mmol) was allowed to stand at room temperature for a suitable time. Washing with suitable solvent afforded the pure solid product 5. 

Appropriate 2-aminobenzenethiol 1 (2 mmol) and /(-kctocstcr or /(-di ketone 2 (2 mmol) were introduced in a beaker (100 mL) and dissolved in chloroform (5 mL). Basic alumina (S.D. Fine Chemicals Pvt. Ltd., 5 g) was then added and swirled for a while followed by removal of solvent under gentle vacuum. The dry powder thus obtained was irradiated in a microwave oven at power output of 520 W for an appropriate time (monitored by TLC). The inorganic support (which can be reused 3-4 times without any loss of activity) was separated by filtration after eluting the product with acetone (5x20 mL). The filtrate was dried over sodium sulfate and the product, obtained after removal of solvent, was recrystallized from methanol as colored crystals in good yields. 

Trimethoxybenzaldehyde lc (0.196 g, 1.0 mmol), hydroxylamine hydrochloride (0.077 g, 1.1 mmol) and peroxymonosulfate (0.61 g, 1.0 mmol) doped on a neutral alumina (1.0 g) were mixed thoroughly on a vortex mixer. The reaction mixture was placed in an alumina bath inside a commercial microwave oven (operating at 2450 MHz frequency) and irradiated for a period of 7 min. After completion of the reaction (monitored by TLC) the inorganic support was separated by filtration, after eluting the product with dichloromethane (2x 15 mL). The solvent was removed and the residue on purification by column chromatography on silica gel gave the corresponding trimethoxybenzonitrile 2a in 95% yield and there was no evidence for the formation of any side products. 

Ultrasonic extraction (USE) it is a simple extraction technique, in which the sample is immersed in an appropriate organic solvent in a vessel and placed in an ultrasonic bath. The efficiency of extraction depends on the polarity of the solvent, the homogeneity of the matrix and the ultrasonic time. The mixture of sample and organic solvent is separated by filtration [40,41],... 

The asphaltene fraction (ASTM D-893 ASTM D-2007 ASTM D-3279 ASTM D-4124 ASTM D-6560 IP 143) is the highest molecular weight and most complex fraction. In any of the methods for determination of the asphaltene content, the sample is mixed with a large excess (usually >30 volumes hydrocarbon per volume of sample) of low-boiling hydrocarbon, such as n-pentane or n-heptane. For an extremely viscous sample, a solvent such as toluene may be used prior to addition of the low-boiling hydrocarbon, but an additional amount of the hydrocarbon (usually >30 volumes hydrocarbon per volume of solvent) must be added to compensate for the presence of the solvent. After a specified time, the insoluble material (the asphaltene fraction) is separated (by filtration) and dried. The yield is reported as a percentage (% w/w) of the original sample. 

Kodomari, M. Noguchi, T. Aoyama, T. Synth. Commun., 2004, 34, 1783) Chalcone 2 (0.28 g, 1 mmol) and or /zo-phenylenediamine 1 (0.16 g, 1.5 mmol) were dissolved in diethyl ether (20 ml). Alumina (neutral, 2 g) was then added to the mixture and the mixture was stirred for a while, followed by removal of the solvent under reduced pressure. The mixture was stirred at 80°C for 3 h under a nitrogen atmosphere. Alumina was separated by filtration after eluting the product with ethyl acetate (20 ml). After the solvent had been evaporated under reduced pressure, the residue was purified by column chromatography on silica gel (hexane-ethyl acetate 10 1) to yield 3 (81 %) as a yellow solid. 

A hyperfiltration process developed by Mobil Oil, now ExxonMobil, for this separation is illustrated in Figure 5.28(b). Polyimide membranes formed into spiral-wound modules are used to separate up to 50 % of the solvent from the dewaxed oil. The membranes have a flux of 10-20 gal/ft2 day at a pressure of 450-650 psi. The solvent filtrate bypasses the distillation step and is recycled directly to the incoming oil feed. The net result is a significant reduction in the refrigeration load required to cool the oil and in the size and energy consumption of the solvent recovery vacuum distillation section. 

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