Evaporating solution

Wohler s classical synthesis of urea from ammonium cyanate may be carried out by evaporating solutions of sodium cyanate and ammonium sulphate ... 

Infrared lamps and heaters. Infrared lamps with internal reflectors are available commercially and are valuable for evaporating solutions. The lamp may be mounted immediately above the liquid to be heated the evaporation takes place rapidly, without spattering and also without creeping. Units are obtainable which permit the application of heat to both the top and bottom of a number of crucibles, dishes, etc., at the same time this assembly can char filter papers in the crucibles quite rapidly, and the filter paper does not catch fire. 

Cu(OAc), H20 (0.75 g, 3.7 mmol) was added to a refluxing solution of metal-free 1,4,8,11.15,18,22,25-octa(propyloxy)phthalocyanine (0.1 g, 0.1 mmol) in BuOH (5 mL). The solution was maintained at reflux for 0.5 h, cooled, and chromatographed (silica gel, CH2C12 and Et20). The green-blue fraction eluted first was crystallized from a slowly evaporating solution in CH2Cl2/py yield 0.086 g (81 %). 

The high standard deviations are attributable to the uncertainties associated with powdered samples and with residues formed by evaporating solutions. 

Tears-of-Wine The surface motion of mixed liquids was described in ancient times [29], and scientifically in a paper by James Thompson, the brother of Lord Kelvin [30] in 1855. Recently Neogi [31], and Cazabat [32] reported on the formation of ordered stmctures in evaporating solutions of two liquids. The meniscus of wine in a glass is drawn upward on the glass surface and forms a thin film. Due to its... 

Evaporation of Samples. Six samples of usually 250 ml. each are simultaneously evaporated to a moist residue in a water bath, shown in Figure 7, which is maintained at 80° to 90° C. The exhaust manifold is connected with the house vacuum. With the assemblies shown a gentle stream of air is drawn over the surface of the evaporating solution and out the vacuum line the air inlet tube is lowered frequently so as to maintain a rippled surface on the benzene extract. In this manner, 250 ml. of benzene can be evaporated completely in 10 minutes or less. 

An idea to use polybasic hydroxy carboxylic acids in syntheses of oxides goes back to Pechini [3], Evaporating solutions of metal salts in citric acid at presence of ethylene glycol he obtained a polymeric resin as a precursor of target oxides. Then this process was extensively used to manufacture various ceramic oxide powders in several publications [4-8],... 

Combine the chloroform extracts and evaporate solution until no more chloroform can be smelled. The result is crude coniine. It may be converted to the hydrochloride form by passing dry hydrogen chloride gas through the solution but this is usually unnecessary. 

Mulder FJ, Thiel RC van der Zeeuw EA (unpublished MES results on an absorber produced by dissolving AU55 in CH2CI2 and evaporating solution)... 

To protect a liquid being heated from contamination, cover the beakers with watch glasses. When evaporating solutions (in bowls or beakers), funnels secured above the liquid being heated will serve the same purpose (Fig. 14). 

D EVAPORATE SOLUTION UNTIL ALMOST DRY. DO NOT OVERHEAT—IF YOU DO. THE ACETATE BREAKS UP INTO CALCIUM CARBONATE AND ACETONE (CH,COCH,). 

Partition Column. Two columns packed with coarse powdered cellulose impregnated with capryl alcohol as immobile phase were prepared in an identical manner. The mobile phase consists of 0.2Af phosphate buffer at pH 6.5. To avoid overloading the column, only a small portion of the extract could be used. The natural extract consisted of 0.20 ml. of the reduced-pressure evaporated solution, corresponding to about 10 grams of kudzu. A similar quantity was added as the spiked extract, except that it contained 500 /xg. of added GA3. Ten-milliliter eluent fractions were collected, acidified to pH 2, and extracted with ethyl acetate. The ethyl acetate extracts were concentrated prior to chromatography. 

Fig. 2. Absorption spectrum of [(n-propyl)2NH2]3 [SbCl6] recorded at different temperatures from a film which is prepared by evaporating solutions of CH3CN on a quartz plate. The emission spectrum (2e>c = 367 nm) was recorded from a powder at T = 10 K...

The use of membranes for separating particles of colloidal dimensions is termed dialysis. The most commonly used membranes are prepared from regenerated cellulose products such as collodion (a partially evaporated solution of cellulose nitrate in alcohol plus ether), Cellophane and Visking. Membranes with various, approximately known, pore sizes can be obtained commercially (usually in the form of sausage skins or thimbles ). However, particle size and pore size cannot be properly correlated, since the permeability of a membrane is also affected by factors such as electrical repulsion when. the membrane and particles are of like charge, and particle adsorption on the filter which can lead to a blocking of the pores. 

Evaporate solution and purify the reaction mixture by flash chromatography (see Note 9). 

Evaporated solution is then pumped into the stirred continually operating crystallizers where it is cooled from 90° to 25 °C. All impurities and salt crystals are then allowed to separate in settling vessels. The clear solution is afterwards pumped into storage tanks, where a small amount of sodium hypochlorite is added in order to decolorize the lye. 

General Properties.—The evaporated solution prepared as above deposited crystals of the hydrate H2P03.H20 which had the form of four-sided rectangular plates and melted at 70° C.1 They were very deliquescent, but when kept over sulphuric acid effloresced giving the anhydrous acid, which melted at 55° C. A half-hydrate, HaPO . HaO, which melted at about 80° C. was also obtained by evaporation over sulphuric acid. 

Hydroxylammonium chloride, [HONHsJCl, is commercially available. The corresponding compounds [HONHalBr and [HONHs] are prepared by evaporating solutions of [HONHslCl in the appropriate HX acid until crystallization occurs. The product is recrystallized from the respective aqueous HX. 

Cold barium hydroxide quantitatively removes the sulfite group from 25 and 26. The 5-amino-5-deoxy-D-xylose so liberated exists mainly in the form 17. Only in alkaline solution is it relatively stable toward acids it is extremely sensitive. Compound 17 accordingly behaves fundamentally differently from all other monosaccharides. In neutral solution (obtained by neutralization of its solution in barium hydroxide with carbon dioxide), the Amadori rearrangement product (22) is formed on standing at room temperature. With hydrochloric acid, 22 is likewise formed as the major product, together with 3-pyridinol (21). Free 17 cannot be isolated in pure form the product obtained contains 16 and 22 in proportions that vary with the pH of the evaporated solution. The impurities are lowest at pH 9.6. It is reported that, from the evaporated solution of 17, a 96 % yield of 25 can be recovered, but it should be mentioned that 16 and 22 also react with sulfurous acid to form 25 and 29. Thin-layer chromatograms (silica gel with p-dioxane—water) always show, besides 17, spots for the secondarily formed 16 and 22. 

Micro-Bunsen burner - for heating solutions to boiling and for evaporating solutions. 

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