Dry solutions

Thionyl chloride (11.5g, 96.4 mmol) was added to 2-nitrophenylacetic acid (8.72g, 48.2mmol) and the suspension was warmed to 50°C and stirred until gas evolution was complete. The resulting solution was concentrated in vacuo and the residue dissolved in CHjClj (30 ml). This solution was added dropwise to a stirred solution of Meldrum s acid (6.94 g, 48.2 mmol) in CH2CI2 (200 ml) under nitrogen at 0 C. The solution was stirred at 0" C for 1 h after the addition was complete and then kept at room temperature for an additional hour. The reaction solution was then worked up by successively washing with dil. HC1, water and brine and dried (MgSOJ. The dried solution was concentrated in vacuo and abs. ethanol (200 ml) was added to the residue. The mixture was... 

An aerosol produced instrumentally has similar properties, except that the aerosol is usually produced from solutions and not from pure liquids. For solutions of analytes, the droplets consist of solute and solvent, from which the latter can evaporate to give smaller droplets of increasingly concentrated solution (Figure 19.1). If the solvent evaporates entirely from a droplet, the desolvated dry solute appears as small solid particles, often simply called particulate matter. 

The second term allows for solvation, which effectively increases the volume fraction of the particles to a larger value than that calculated on the basis of dry solute. Equation (9.18) shows how this can be quantified. 

In drying solutions or slurries of solutions, the location of the feed-injection nozzle (spray nozzle) has a great effecl on the size of particle formed in the bed. Also of importance are the operating temperature, relative humidity of the off gas, and gas velocity. Particle growth can occur as agglomeration or as an onion sldnuing. ... 

If an entirely dry solution of diazomethane is required, round pellets of potassium hydroxide should be used. ... 

A solution of 17-cyanoandrosta-5,16-dien-3jS-ol acetate (46 g) and anhydrous potassium acetate (0.46 g) in methylene dichloride (310 ml) is treated with a mixture of 40% peracetic acid (37 ml) and anhydrous potassium acetate (1.84 g) in methylene dichloride (46 ml), the temperature of the solution being maintained below 25°. The mixture is stored at room temperature for 4 hr and then washed successively with water, 5% sodium bicarbonate solution (aqueous sodium bisulfite, 10g/150g water, has been used to decompose excess reagent before workup) and water until neutral. Evaporation of the dried solution and addition of ether gives 24.1 g of 5oc,6a-epoxy-17-cyanoandrost-16-en-3 -ol acetate mp 187-190°. One recrystallization from methanol gives 20.4 g of oxirane melting at 191-194°. 

The reaction mixture is now poured into a separatory funnel with 50 ml of ice water, and the cyclohexanol is removed by two ether extractions. The ether extracts are dried with anhydrous sodium sulfate, and the dried solution is distilled. Cyclohexanol is collected at 154-1607750 mm, expected yield 5-6 g. 

Dried solution may be distilled from drying agent. 

The dried dimethyleminoethyl chloride solution is poured into the toluene solution of the sodium salt of o-benzylphenol, heated to reflux, end refluxed 16 hours. After refluxing, enough water is added to the mixture to dissolve the precipitated solid. The layers ere separated, end the toluene layer is further washed with water until the water extract is just slightly elkeline. The toluene solution is then mede acid with 6N hydrochloric acid end extracted with water until no cloudiness is produced when the extract is mede elkeline. The acidic aqueous extract is washed with ether, then mede elkeline with 20% sodium hydroxide solution, end extracted into ether. The ether solution is washed several times with water, then with saturated salt solution, end is dried over anhydrous potassium carbonate. The dried solution Is filtered end distilled. The product distills at 143.5°C/1 mm 69.7 g of pale yellow oil ere recovered. 

The dried solution is then fractionally distilled in a modified roo-cc. Claisen flask (Org. Syn. 1, 40). The chloroform is removed by distilling at ordinary pressure until the temperature reaches 120° (Note 3). The remainder may be fractionated under ordinary pressure but it is better to use reduced pressure. 

Dry the organic solvent layer through 80 g of anhydrous sodium sulfate on a glass funnel and collect the dried solution in a 300-mL round-bottom flask. Evaporate the solvent under reduced pressure. Dissolve the residue in 150 mL of n-hexane and transfer the solution into a 300-mL separatory funnel. Extract twice with 100 mL of acetonitrile. Combine the acetonitrile extracts in a 500-mL round-bottom flask and evaporate the solvent under reduced pressure. Dissolve the residue in a small amount of column-eluting solvent (dichloromethane-n-hexane, 1 1, v/v) and transfer the solution to the top of the silica gel column. After eluting the column with 60 mL of solvent of the same composition (discard), elute orbencarb and I with 150mL of dichloromethane. Collect the eluate in a 300-mL flask and evaporate the solvent under reduced pressure. Dissolve the residue in an appropriate volume of acetone for analysis. 

Transfer the concentrated crop sample extract (strawberries, rice grain, barley grain and rice straw) into a 50-mL separatory funnel with a small volume of water. Extract the solution three times with 10 mL of a chloroform-methanol (3 1, v/v). Dry the chloroform-methanol layer with a small amount (about 8 g) of anhydrous sodium sulfate on a glass funnel and transfer the dried solution to a 100-mL separatory funnel. 

Combine the aqueous layers, add 3.5 mL of concentrated sulfuric acid and extract the solution twice with 60 mL of a mixture of chloroform and methanol. Dry the chloroform-methanol layer with anhydrous sodium sulfate and collect the dried solution in a 200-mL round-bottom flask. Evaporate the solvent under reduced pressure. 

Transfer crop and soil samples from Section 6.1 (strawberry and rice grain) and Section 6.2 with 5 mL of methanol to 30-mL test-tubes and add to each test-tube 0.05 mL of concentrated sulfuric acid. Attach a condenser and reflux the solution at 75 °C for 60 min to esterify prohexadione to its corresponding methyl ester. Cool the reaction mixture to room temperature, add 20 mL of water and extract the reaction solution twice with 20 mL of dichloromethane. Dry the dichloromethane layer with a small amount of anhydrous sodium sulfate and collect the dried solution in a 100-mL round-bottom flask. Evaporate the solvent under reduced pressure. 

Transfer the soil extract (from Section 6.1) into a 1000-mL separatory funnel, add 200 mL of water and 10 mL of saturated sodium chloride solution, and extract the sample with 100 mL of dichloromethane three times. Dry the dichloromethane extract with anhydrous sodium sulfate in a funnel in a similar manner as described for juice, pulp and rind, and collect the dried solution in a 500-mL round-bottom flask. Evaporate the dichloromethane under reduced pressure. Dissolve the residue in 3 mL of benzene. 

Figure 1. Electron micrographs of xanthan sample A (A), sample B (B) sample C (C) and sample D (D). The electron micrographs were obtained from replicas of vacuum dried solutions containing 100 mM NH4Ac, 50% glycerol and 3 -10 ]ig /ml polymer. Scale bar = 200 nm.

A 500-ml. three-necked flask is fitted with a reflux condenser and a thermometer, the bulb of which reaches far enough into the flask to be covered by the liquid. A solution of 46.0 g. (0.205 mole) of a-phenylcinnamic acid (p. 70) (Note 1) in 280 ml. (307 g., 2.38 moles) of quinoline (Note 2) is added to the flask along with 4.0 g. of copper chromite.2 The reaction flask is heated by means of a mantle or an oil bath until the temperature of the reaction mixture reaches 210-220°. The mixture is kept within this temperature range for 1.25 hours. The solution is then cooled immediately and added to 960 ml. of 10% hydrochloric acid in order to dissolve the quinoline (Note 3). The product is extracted from this mixture with two 200-ml. portions of ether followed by a 100-ml. portion. The combined ether extracts are filtered to remove particles of catalyst, washed with 200 ml. of 10% sodium carbonate, and dried over anhydrous sodium sulfate. The dry solution is removed from the drying agent by filtration and heated on a steam bath to distil the ether. The residue is dissolved in a hexane fraction, b.p. 60-72° (Skellysolve B) the solution is cooled to 0° and filtered to remove /raws-stilbene, if any. The hydrocarbon solvent is removed by distillation, and the czs-stilbene is distilled. The yield is 23-24 g. (62-65%), b.p. 133-136°/10 nun., 95-97°/l mm. tig 1.6183-1.6193, 1.6212-... 

Alkyl-NH2/NHR 5-1 Generally similar to alkyl-OH but maybe somewhat broader even in dry solutions and less likely to couple to adjacent protons. Ability to protonate nitrogen tends to broaden protons and displace to lower field. Easily exchanged. 

A dry solution of the sodium salt in n-butanol was usually prepared by azeotropic drying. Use of excessively wet recovered butanol led to complete removal of the butanol with the water and heating of the dry salt at 200°C, when rapid decomposition occurred, leaving a glowing carbonised residue. 

The dried solution is distilled, first at atmospheric pressure to remove most of the solvent, and then under reduced pressure (Note 5). A fore run of unused naphthalene amounting to 35-40 g. is collected at 90-110°/5 mm. (Note 6). This is followed by 195-204 g. of 1-chloromethylnaphthalene which boils at 128 133°/5 mm. or at 148-153°/14 mm. (74-77% based on naphthalene consumed) (Notes 7 and 8). 

Flink, J., Karel, M. Retention of organic volatiles in freeze-dried solutions of carbohydrates. Reprinted with permission from Journal of Agricultural and Food Chemistry, Vol. 18, No. 2, S. 295, 1970, Copyright 1970 American Chemical Society, Washington, DC 20005, USA... 

The dried solution is transferred to a 2-1. flask fitted with a Claisen head attached to a 30-cm. Vigreux column. Benzene is... 

Restoring the solution concentration by adding dry solute or mixing with concentrated solution can save energy costs as it avoids heat of evaporation and the need for expensive plants. The method can be suggested successfully for small-scale production, at a low-technological level process, where the initial solution mass is small. Indeed, the main hurdle of this technique is the increase of the solution mass, even if a constant loss in volume of syrup (9-14%) is due to adherence to the food pieces (Bolin et al., 1983). 

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