Rotating evaporator

A solution of 30 g (0.1 mole) of 17j5-hydroxy-5a-androstan-3-one (androstano-lone), 20 ml of pyrrolidine and 200 ml of benzene is heated at reflux temperature for 2.5 hr under a Bidwell-Sterling water trap. The benzene solution is evaporated to dryness in a rotating evaporator connected to a water aspirator. The white cake which remains is broken up and dried further by immersing the flask in a water bath at 60-75° and evacuating the flask with a mechanical vacuum pump. After 0.5 hr the solid cake is broken up again and dried for another 0.5 hr at 60-75°. The enamine (9) obtained should smell only faintly of pyrrolidine. 

A mixture of 72 g hesperidin, 288 ml acetic anhydride and 300 ml glacial acetic acid were boiled in reflux with 15 ml pyridine as the catalyst for 144 hours until during the control of the reaction the band disappeared at a wave length between 264 to 280 nm, and a new maximum appeared at 330 nm. Thereafter in a rotation evaporator the reaction mixture was concentrated by evaporation under vacuum conditions. 

A platinum-iron on silica gel catalyst was prepared by impregnating silica gel (BDH, for chromatographic adsorption) with an aqueous solution of chloroplatinic acid (analytical grade) and sodium hydroxide (analytical grade). The dry product was then impregnated by a ferrous sulfate solution (C.P. grade) and the water was removed in a rotating evaporator. The prepared catalyst contained 1% Pt, 0.7% Fe, and 2% NaOH (by... 

Extraction Procedure. We modified the extraction procedure of Nelson et al (10). Brie acidified with 2 ml of 5% trichloracetic acid (TCA) was extracted 3 times with 20 ml of petroleum ether. The combined extracts were reduced to 5 ml in a rotating evaporator, returned to the separatory funnel, and combined with 60 ml each of acetonitrile and distilled water. The acetonitrile-water-insecticide mixture was extracted twice with 60 ml of petroleum ether and anhydrous Na2S04 was added to the combined 120 ml extract. The extract was evaporated just to dryness and the residue was dissolved in benzene for analysis by gas-liquid chromatography (GLC). Extraction efficiencies in spiked experiments were 73% (aldrin) and 83% (dieldrin). 

A standard procedure for manufacturing liposomes is the film-forming method where the phospholipids are dissolved in an organic solvent. By rotational evaporation of the solvent a thin, multilayered film of phospholipids arises at the inner wall of the vessel. Redispersion of this film in water or aqueous buffer results in the formation of vesieles. The size of these vesicles and the number of bilayers vary. Henee further manufaeturing steps have to follow to obtain defined vesieular dispersions with a suffieiently long shelf life. 

Then the water is removed in a rotational evaporator resulting in two solid phases.The lower, yellowish phase is very compact and adheres to the flask it contains only sodium acetate.The upper phase is a light powder and contains only poly(ethyleneimine). 

Extraction of sediment samples. Prior to extraction, sediment samples were freeze-dried and homogenized. Approximately 10 g of dried sediment were placed in a preextracted thimble, and a small piece of silanized glass wool was placed in the thimble on top of the sample to prevent sediment parts from leaving the thimble. The thimble was placed in a Soxhlet setup and extract for 16 h (overnight) with 200 ml hexane/acetone (3/1 v/v). The extracts were concentrated in the rotation evaporator until approximately 5 ml (/ = 0.05 bar T = 40°C) of extract remained. If the extraet still contained solid particles, the extract was filtered with diatomaceous earth or sodium sulfate. The extract was transferred to a diatomaceous earth- or sodium sulfate-filled funnel and flushed with 10 ml hexane. The eluted extract was evaporated again in the rotary evaporator until approximately 5 ml of extract remained. The extract was transferred to a cleaned glass tube and concentrated until near dryness. The dried extract was finally redissolved in 3 ml hexane. 

The column was eluted with 130 ml of hexane, after whieh the eluate was eoneentrated on the rotation evaporator until approximately 5 ml remained (p = 0.2 bar T = 40°C). The eoneentrated cleaned sediment extraet was transferred to a elean glass tube and further eoneentrated to near dryness under a gentle stream of nitrogen. The extraet was redissolved in 50 p,l DMSO. 

Preparations of the Free Amine. Since 2,5 TDA was supplied as the sulphate salt it was necessary to prepare the free amine. This was done by dissolving the diamine salt in sodium chloride saturated distilled water acidified with a few drops of sulphuric acid. Methylene chloride was added to this solution in a separating funnel. Sodium hydroxide was added to adjust the pH to 10-11 to transfer the amine to the organic phase, the methylene chloride now containing the diamine was washed once with saturated sodium chloride and then evaporated in a rotating evaporator. Red crystals of 2,5-TDA resulted from the evaporation. The purity was checked chromatographically. 

The submitters strongly recommend the use of a rotating evaporator (such as the Flash-Evaporator, Laboratory Glass Supply Co., New York 31, N. Y.) with which the solution can be reduced to a syrup in about 4 hours. The further evaporation is facilitated by adding 100 ml. of commercial absolute ethanol at this point and continuing the evaporation. Total time for evaporation will be about 6 hours, and the product will be a crystalline mass. The extraction step may be carried out in the 2-1. flask normally used with the evaporator. 

If a rotating evaporator is not available, the solution is poured into a large porcelain evaporating dish and is allowed to stand protected in the hood for several days. Toward the end of this time, the evaporation may be accelerated by the addition of 100... 

The filtrate obtained from this reaction mixture is reduced to a volume of 15.0mL in a rotating evaporator and purified by means of thin layer chromatography (TLC) preparative plates of 1-mm thickness (Kieselgel P. F. Merck) eluant diethyl ether (5% vol) in light petroleum ether. The dark brown band of the complex is eluted with dry diethyl ether (peroxide-free). 

The filtrate is kept to dryness in a rotating evaporator the product... 

Fig. 15.41 An inexpensive apparatus constructed from a modified rotating evaporator and used to vaporize metals for condensation with ligands. [Adapted from Murkle. R. J. Pctiiiohn. T. M. Logowski, 1.1. Oreanomviottics 1985,4. L529-(J3I. Used with pemus-don.)...

When aluminum-silicon (Al-Si) metallization was deposited on wafers by evaporation, wet chemical analysis was used to study the changes in concentrations of Al to Si in the single evaporating cup. Wet chemical analysis was also used to determine the uniformity of silicon in aluminum and the evaporation patterns on the wafers in a rotating evaporator. The results revealed an accumulation of silicon in the cup and clearly showed the total lack of uniformity within a wafer and from wafer to wafer. The study showed why metallization problems were occurring and how to stop them. 

Dichlorophenyl)-l-piperazinopropionitrile (20.0 g), acetic anhydride (100 ml), anhydrous sodium sulfate (12.0 g) and a 50% solution of Ni-Raney (6 ml) are hydrogenated at 60.0 pounds per inch at 60°C in a Parr apparatus. After about half an absorption of hydrogen is complete. The reaction mixture is cooled, the is filtered and the solution is concentrated to small volume in a rotating evaporator. The residue is treated with NaOH solution and extracted several times CH2CI2. The organic layer is washed, dried and evaporated. The residue is crystallized from ethyl acetate. 14.0 g of the l-(3-acetylaminopropyl)-4-(2,5-dichlorophenyl)piperazine are obtained, melting point 114°C. 

The ether solutions are combined, and the solution is dried over 100 g. of calcium chloride for at least 3 hours. The purple solution is filtered and then evaporated in a rotating evaporator to a syrupy residue. The tarry red residue is dissolved in 100 ml. of hot (70°) benzene. The benzene solution is allowed to cool and is then poured onto a chromatographic column (approximately 35 X 300 mm.) packed under benzene with 50 g. of activated aluminum oxide. A dark violet band is rapidly eluted from the column with methylene chloride (dichloromethane). Evaporation of the violet methylene chloride solution yields 2.2 to 2.8 g. of purple crystals (20 to 26%) m.p. 182 to 183°. 

If the compound to be distilled is in solution, it is now necessary to remove the solvent. If the solvent has a boiling point close (within 100°) to that of the compound, it is necessary to effect the removal of the solvent with as much care as is used in the distillation of the compound. If the solvent has a much lower boiling point than the compound, it is convenient to remove it by using a Hopkins head (Fig. 1-14) or a rotating evaporator (Fig. 1-15), usually under... 

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