Salt solution, evaporation

Now distil the filtrate A) and collect the distillate as long as it is acid to litmus. Should any solid separate out in the distilhng flask during the distUlation, add more water to dissolve it. Set aside the residue B) in the flask. Identify the volatile acid in the distihate. A simple method is to just neutralise it with sodium hydroxide solution, evaporate to dryness and convert the residual sodium salt into the S-benzyl-iao-thiuTonium salt (Section 111,85,5). 

Sodium fluorosulfate may be prepared by the action of fluorosulfuric acid on powdered, ignited sodium chloride (13) or of sulfur trioxide on sodium fluoride (48). In general, the alkah metal fluorosulfates may be prepared from the ammonium salt by evaporating a solution containing that salt and an alkah metal hydroxide (77). The solubiUties of some Group 1 and 2 fluorosulfates in fluorosulfuric acid have been deterrnined (93). 

The chlorides, bromides, nitrates, bromates, and perchlorate salts ate soluble in water and, when the aqueous solutions evaporate, precipitate as hydrated crystalline salts. The acetates, iodates, and iodides ate somewhat less soluble. The sulfates ate sparingly soluble and ate unique in that they have a negative solubitity trend with increasing temperature. The oxides, sulfides, fluorides, carbonates, oxalates, and phosphates ate insoluble in water. The oxalate, which is important in the recovery of lanthanides from solutions, can be calcined directly to the oxide. This procedure is used both in analytical and industrial apptications. 

Coppet(II) oxide [1317-38-0] CuO, is found in nature as the black triclinic tenorite [1317-92-6] or the cubic or tetrahedral paramelaconite [71276-37 ]. Commercially available copper(II) oxide is generally black and dense although a brown material of low bulk density can be prepared by decomposition of the carbonate or hydroxide at around 300°C, or by the hydrolysis of hot copper salt solutions with sodium hydroxide. The black product of commerce is most often prepared by evaporation of Cu(NH2)4C02 solutions (35) or by precipitation of copper(II) oxide from hot ammonia solutions by addition of sodium hydroxide. An extremely fine (10—20 nm) copper(II) oxide has been prepared for use as a precursor in superconductors (36). 

Highest heat-transfer coefficients are obtained in FC evaporators when the liquid is aUowed to boil in the tubes, as in the type shown in Fig. 11-122 7. The heating element projects into the vapor head, and the hquid level is maintained near and usuaUy slightly below the top tube sheet. This type of FC evaporator is not well suited to salting solutions because boiling in the tubes increases the chances of salt deposit on the waUs and the sudden flashing at the tube exits promotes excessive nucleation and production of fine ciystals. Consequently, this type of evaporator is seldom used except when there are headroom hmitations or when the hquid forms neither salt nor scale. 

Experimental curves for the angular dependence of the fluorescence intensity from plated or sputtered submonatomic Ni layers (open triangles), layers produced by the evaporation of a Ni salt solution (open circles), and the silicon substrate (filled circles). 

In a 250 ml Erlenmeyer flask covered with aluminum foil, 14.3 g (0.0381 mole) of 17a-acetoxy-3j5-hydroxypregn-5-en-20-one is mixed with 50 ml of tetra-hydrofuran, 7 ml ca. 0.076 mole) of dihydropyran, and 0.15 g of p-toluene-sulfonic acid monohydrate. The mixture is warmed to 40 + 5° where upon the steroid dissolves rapidly. The mixture is kept for 45 min and 1 ml of tetra-methylguanidine is added to neutralize the catalyst. Water (100 ml) is added and the organic solvent is removed using a rotary vacuum evaporator. The solid is taken up in ether, the solution is washed with water and saturated salt solution, dried over sodium sulfate, and then treated with Darco and filtered. Removal of the solvent followed by drying at 0.2 mm for 1 hr affords 18.4 g (theory is 17.5 g) of solid having an odor of dihydropyran. The infrared spectrum contains no hydroxyl bands and the crude material is not further purified. This compound has not been described in the literature. 

A total of 50 ml (0.15 moles) of a 3 ethereal solution of methylmagnesium bromide is added slowly to a vigorously stirred solution of 5.8 g (12.5 mmoles) or 3,3 20,20-bisethylenedioxy-5a,6a-epoxy-5a-pregnane-ll/l,17a,21-triol in 400 ml of tetrahydrofuran. The solution is heated under reflux for 24 hr, cooled and treated with 32 ml of saturated ammonium chloride solution. The supernatant is decanted and the residue is washed with several portions of tetrahydrofuran. The combined supernatants are evaporated and extracted with ethyl acetate, washed with saturated salt solution, dried and concentrated to give 4,55 g (75%) of 3,3 20,20-bisethylenedioxy-6 -methyl-5a-pregnane-5a,ll, 17a,21-tetrol mp 170-172° after crystallisation from acetone-petroleum ether. The analytical sample is crystallized from acetone-petroleum ether mp 175-177° [aJo —11° (CHCI3). 

A-Homo-estra- Q>),2,Aa-triene-4, l-dione (45) from the l-ketal mono-dibromocarbene adduct (43b). A solution of monoadduct 17-ketal (43b 0.46 g) and dry pyridine (20 ml) is heated at reflux for 2 hr. After cooling the reaction mixture, the pyridine hydrobromide (0.1 g) is removed by filtration and the filtrate is concentrated under reduced pressure. The resultant gum is dissolved in ether and washed successively with water, ice-cold 4 N hydrochloric acid, water, 5% aqueous sodium bicarbonate solution, water, saturated salt solution and dried over anhydrous magnesium sulfate. Evaporation of the solvent at reduced pressure gives 3-bromo-4-methoxy-A-homo-estra-2,4,5(10)-trien-17-one (44 0.22 g) mp 158-162° after crystallization from ether. 

Bromo-4-methoxy-A-homo-estra-2,4,5(10)-trien-17-one (44 0. 2g), is dissolved in formic acid, 2 ml of boron trifluoride etherate is added and the mixture is stirred vigorously at 0° for 2 hr. A brown mass ca. 0.12 g) is obtained after evaporation of the solvents at reduced pressure. This material is diluted with water and extracted with chloroform. The chloroform extracts are washed successively with water and saturated salt solution, dried over anhydrous magnesium sulfate and evaporated at reduced pressure to give 95 mg of a product which is purified by filtration through a column of neutral alumina and crystallization of the residue after evaporation of the solvent from ethyl acetate-petroleum ether. The resulting A-homo-estra-l(10),2,4a-triene-4,17-dione (45), mp 143-146°, is identical to the tropone (45) prepared from monoadduct 17-ketone (43a). 

Bromo-A-homo-estra-4y5 0)-diene-3, l-dione (49). A solution of silver perchlorate (0.55 g, 5 mole-eq) in acetone (2 ml) is added to a refluxing solution of monoadduct (48 0.28 g) in acetone (30 ml) containing water (0.5 ml). After being heated at reflux for 25 min the reaction mixture is cooled and the precipitated silver bromide is removed by filtration, yield about 0.11 g. The filtrate is diluted with water (500 ml) and is thoroughly extracted with chloroform. The chloroform extracts are washed with water and saturated salt solution, dried over anhydrous magnesium sulfate, and evaporated at... 

After an additional 10 min, a 1 % solution of hydrochloric acid (100 ml) is slowly added to the stirred reaction mixture and the resultant mixture is transferred to a separatory funnel. The ether layer is separated and washed sequentially with water, 5 % sodium bicarbonate solution, water and saturated salt solution. The washed ether solution is dried over anhydrous sodium sulfate, filtered, and evaporated to give an oily residue (0.45 g). Chromatography of the crude product on silica gel (50 g) followed by crystallization of the solid thus obtained (0.18 g) from ethanol gives 3 -hydroxy-B-homo-cholest-5-en-7a-one acetate (67 0.14 g) mp 90-91° [a]o 99° (CHCI3). 

A solution of the crude cyanohydrin (94a ca. 1 g) in pyridine (15 ml) and acetic anhydride (15 ml) is allowed to stand at room temperature for 52 hr. The solvents are evaporated under reduced pressure below 60°. The residue is dissolved in ether, and the ether solution is washed successively with 5 % hydrochloric acid, water and saturated salt solution. The solvent is evaporated under reduced pressure to give a crystalline residue. Recrystallization of the crude product from cyclohexane-acetone gives 3-methoxy-17a-cyano-estra-l,3,5(10)-trien-17i5-ol acetate (94b 0.9 g), mp 130-132°, as large prisms. 

A solution of cholestane-5a,6a-diol 6-tosylate (115a, 0.15 g) in dimethylformamide (20 ml) containing calcium carbonate (0.2 g) is heated for 8 hr on a steam bath. The reaction mixture is then cooled, filtered and diluted with water. The mixture is extracted with ether and the ether extracts are washed with water and saturated salt solution, dried over anhydrous magnesium sulfate and evaporated to dryness under reduced pressure to give the A-homo-B-norketone (116a, 85 mg) mp 123-125° [a]j> 21° (CHCI3). 

To a suspension of 25.0 g of 11/3,17a,21-trihydroxy-6,16a-dimethyl-4,6-pregnadiene-3,20-dione in 1.5 liters of alcohol-free chloroform cooled to about 5°C in an ice bath is added with constant stirring 750 ml of cold, concentrated hydrochloric acid and then 750 ml of formalin (low in methanol). The mixture is removed from the ice bath and stirred at room temperature for 7 hours. The layers are separated and the aqueous phase is back-extracted twice with chloroform. The combined organic layers are washed twice with a 5% solution of sodium bicarbonate, and twice with a saturated salt solution. The solution is dried over magnesium sulfate and evaporated to dryness under reduced pressure. 

B) t-Butyl 2-Methyl-5-Methoxy-3-lndolylacetate t-Butyl alcohol (25 ml) and fused zinc chloride (0.3 g) are added to the anhydride from Part A. The solution is refluxed for 16 hours and excess alcohol is removed in vacuo. The residue is dissolved in ether, washed several times with saturated bicarbonate, water, and saturated salt solution. After drying over magnesium sulfate, the solution is treated with charcoal, evaporated, and flushed several times with Skellysolve B for complete removal of alcohol. The residual oily ester (18 g, 93%) is used without purification. 

The alcoholic ethereal filtrate is then dried over calcined potassium carbonate and the solution evaporated, whereby 0.9 to 1 part of a mixture of d-lysergic acid-d-l-hydroxybutyl-amide-2 and of d-isolysergic acid-d-l-hvdroxvbutylamide-2 is obtained. In order to separate the isomers, the residue is dissolved in 15 parts of hot chloroform and filtered from the small quantity of inorganic salt, whereby on cooling down, the difficultly soluble chloroform compound of d-lysergic acid-d-l hvdroxvbutylamide-2 crystallizes out. Yield 0.4 part. This compound can be recrystallized from hot benzene, whereby crystals melting... 

The precipitate is taken up in chloroform, the solution obtained is washed twice with water, then with saturated salt solution, dried over Na SO and evaporated under vacuum (bath temperature 20°C). The residue is recrystallized from alcohol and produces (-(p-benzyloxy-phenvl)-2-phenvl-4-n-butvi-3,5-dioxo-pyrazolidine (C) as tiny white needles which melt at 132° to 133°C. 

After 6 hours the calculated amount of hydrogen has been taken up. The residue obtained after filtering and evaporating is taken up in benzene and extracted twice with diluted sodium carbonate solution. The alkali extract is then made acid to Congo red with 6N hydrochloric acid and the precipitate is taken up in ethyl acetate. The solution obtained is washed twice with salt solution, dried with sodium sulfate and evaporated. The residue is recrystallized from ether/petroleum ether. 1-(p-hydroxyphenyl)-2-phenyl-4-n-butyl-3,5-dioxo-pyrazolidine melts at 124° to 125°C. 

The diamine and the diacid form a PA salt that is soluble in water at elevated temperatures. The polymerization from the PA salt solution occurs in two or three stages. In the first stage a prepolymer is made. This step is carried out under pressure to prevent the evaporation of the more volatile diamine. In the second stage, a polymer is made in the melt phase at atmospheric or slightly reduced pressure. 

The synthetic procedures for isolation of the salt appear to be rather simple. First, one prepares a solution in which the carbocation and carbanion coexist free from any combination reactions. Then, the hydrocarbon cation-anion salt is isolated after separation of the concomitant inorganic salt and evaporation of the solvent. For the purification of the crude salt recrystallization or reprecipitation with proper solvents is used. 

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