Water acidified

Chlorine water (acidified NaCIO solution) No action No action Br2 liberated I2 liberated... 

To a mixture of 10 g. of the compound and 3-5 ml. of 33 per cent, sodium hydroxide solution in a test-tube, add 2-5 ml. of 50 per cent, chloroacetic acid solution. If necessary, add a little water to dissolve the sodium salt of the phenol. Stopper the test-tube loosely and heat on agently-boiling water bath for an hour. After cooling, dilute with 10 ml. of water, acidify to Congo red with dilute hydrochloric acid, and extract with 30 ml. of ether. Wash the ethereal extract with 10 ml, of water, and extract the aryloxyacetic acid b shaking with 25 ml. of 5 per cent, sodium carbonate solution. Acidify the sodium carbonate extract (to Congo red) with dilute hydrochloric acid, collect the aryloxyacetic acid which separates, and recrystallise it from hot water. 

Coumarin. In a 250 ml. round-bottomed flask, provided with a small reflux condenser and a calcium chloride drying tube at the top, place 2 1 g, of salicylaldehyde, 2 0 ml. of anhydrous triethylamine and 5 0 ml. of acetic anhydride, and reflux the mixture gently for 12 hours. Steam distil the mixture from the reaction flask and discard the distillate. Render the residue in the flask basic to litmus with solid sodium bicarbonate, cool, filter the precipitated crude coumarin at the pump and wash it with a little cold water. Acidify the filtrate to Congo red with... 

Other sulfur compounds such as thiourea, ammonium dithiocarbamate, or hydrogen sulfide also lead to 2-mercaptothiazoles. Thus thiourea has been used in the syntheses of 4,5-dimethyl (369) and 4-aryl-2-mercapto-thiazoles (Table 11-30) (519). The reactions were carried out by condensing the ia -thiocyanatoketones with thiourea in alcohol and water acidified with hydrochloric acid. By this procedure, 4-aryl-2-mercaptothiazoles were obtained in yields of 40 to 80% with bis-(4-aryl-2-thiazolyl) sulfides as by-products (519). These latter products (194) have also been observed as a result of the action of thiourea on 2-chloro-4-arylthiazole under the same experimental conditions. They can be separated from 2-mercaptothiazoles because of their different degrees of solubility in sodium hydroxide solution at 5%. In this medium bis-(4-phenyl-2-thiazolyl)sulfide is... 

Reactions were carried out by condensing a-thiocyanatokeiones with thiourea in alcohol and water acidified with hydrochloric acid. 

Alkaline arsenite, O.IA As(lll) to As(V). Dissolve 4.9460 g of primary standard grade AsjOj in 40 mL of 30% NaOH solution. Dilute with 200 mL of water. Acidify the solution with 6N HCl to the acid color of methyl red indicator. Add to this solution 40 g of NaHC03 and dilute to 1 L. 

Tin ores and concentrates can be brought into solution by fusing at red heat in a nickel cmcible with sodium carbonate and sodium peroxide, leaching in water, acidifying with hydrochloric acid, and digesting with nickel sheet. The solution is cooled in carbon dioxide, and titrated with a standard potassium iodate—iodide solution using starch as an indicator. 

Dinitrophenol [51-28-5] M 184.1, m 114 , pK 4.12. Crystd from benzene, EtOH, EtOH/water or water acidified with dil HCl, then recrystd from CCI4. Dried in an oven and stored in a vac desiccator over CaS04. 

Cyano-3 -hydroxy-5a-pregnan-20-one A suspension of 5a-pregnane-3, 20-dione (2 g) in ethanol (90 ml) is treated with acetone cyanohydrin (4 ml) and three drops of triethylamine and stirred at room temperature until complete dissolution. After 3 hr, the solution is diluted with 200 ml of water, acidified with acetic acid and the crystalline precipitate is thoroughly washed with water and dried under vacuum to give 2.1 g (97%) of product mp 172-178° (dec). A sample recrystallized from ethyl acetate melts at 176-179° (dec) [a]p 86° (ethyl acetate). 

Reacimj.—Dissolve a few ciystals in water, acidify with dilute hydrochloric acid, and add a drop of sodium nitrite solution. A deep biown solution (Bismarck brown) is obtained. See Appendix, p. 279. 

Hydrolytic cleavage of the methylmercapto group usually proceeds very readily and in practically quantitative yield even on short boiling in water acidified with a few drops of hydrochloric acid. The readiness of the hydrolysis can be affected very substantially by substitution as shown in the case of 4-methyl-3-methylmercapto-5-thioxo-4,5-dihydro-l,2,4-triazine which was hydrolyzed only with ZN hydrochloric acid. "... 

A 1.5 to 2 M solution of methylsulfinyl carbanion in dimethyl sulfoxide is prepared under nitrogen as above from sodium hydride and dry dimethyl sulfoxide. An equal volume of dry tetrahydrofuran is added and the solution is cooled in an ice bath during the addition, with stirring, of the ester (0.5 equivalent for each 1 equivalent of carbanion neat if liquid, or dissolved in dry tetrahydrofuran if solid) over a period of several minutes. The ice bath is removed and stirring is continued for 30 minutes. The reaction mixture is then poured into three times its volume of water, acidified with aqueous hydrochloric acid to a pH of 3-4 (pH paper), and thoroughly extracted with chloroform. The combined extracts are washed three times with water, dried over anhydrous sodium sulfate, and evaporated to yield the jS-ketosulfoxide as a white or pale yellow crystalline solid. The crude product is triturated with cold ether or isopropyl ether and filtered to give the product in a good state of purity. 

D) Preparation of 2-(1-Hydroxyethyi)-3-Methyi-5-(2-Oxo-2,5-Dihydro-4-Furyi)Benzo[b] Furan (3574 CB) 13,2 grams of compound 3556 CB of which the preparation is described in (C) are treated successively with 66 ml of methylene chloride, 27 ml of methanol and, with stirring, 1.6 grams of sodium borohydride added in stages. The reaciton takes 1 hour. The mixture is poured into water acidified with a sufficient amount of acetic acid, the solvents are stripped under vacuum, the crystalline product removed, washed with water, and recrystallized from ethyl acetate. Yield 90%. MP <=158°C. 

When addition is complete the mixture is heated under reflux during 5 hours and then the acetone is removed by distillation. The residue is dissolved in water, acidified with hydrochloric acid and the mixture extracted with chloroform. The chloroform extract is stirred with sodium hydrogen carbonate solution and the aqueous layer is separated. The alkaline extract is acidified with hydrochloric acid and filtered. The solid product is drained free from oil on a filter pump, then washed with petroleum ether (BP 40° to 60°C), and dried at 50°C. The solid residue, MP 114° to 116°C, may be crystallized from methanol (with the addition of charcoal) to give p-chlorophenoxyisobutyric acid, MP 118° to 119°C. 

In about 250 cc of liquid ammonia (cooled with dry ice and acetone) are dissolved about 7.5 g of potassium and into the solution acetylene is passed until the blue color has disappeared (about 3 hours). Then slowly a solution or suspension of 3 g of estrone in 150 cc of benzene and 50 cc of ether is added. The freezing mixture is removed, the whole allowed to stand for about 2 hours and the solution further stirred overnight. Thereupon the reaction solution is treated with ice and water, acidified with sulfuric acid to an acid reaction to Congo red and the solution extracted five times with ether. The combined ether extracts are washed twice with water, once with 5% sodium carbonate solution and again with water until the washing water is neutral. Then the ether is evaporated, the residue dissolved in a little methanol and diluted with water. The separated product is recrystallized from aqueous methanol. The yield amounts to 2.77 g. The 17-ethiny I-estradiol-3,17 thus obtained melts at 142°C to 144°C . 

It is not necessary that the intermediate be separated from the reaction medium in the preparation of the end product. Instead, the reaction mixture, after cooling, is treated with 200 ml of water acidified with 42 ml 10% hydrochloric acid solution, and filtered. To the clear, light yellow filtrate is added dropwise a solution of 9.B g (0.07 mol) 5-nltro-2-furaldehyde in 100 ml ethyl alcohol. An orange solution of the hydrochloride results. The free base is precipitated asyellow plates by making the solution basic with saturated sodium carbonate solution. 14 g of the compound is filtered off by suction, washed with alcohol, and dried. The yield, MP 204°C to 205°C (dec.), is 53% of theoretical based on 3-(N-morpholinyl)-1,2-epoxy-propane. Recrystallization from 95% alcohol (75% recovery) raises the melting point to 206°C (dec.). 

To a solution of 18.9 grams (0.166 mol) n-heptaldehyde in 25 ml of isopropanol is added, with stirring, a solution of 19,1 grams (0.166 mol) of 1-aminohydantoin in 110 ml water acidified with concentrated HCI. The heavy white precipitate formed is filtered and washed, until acid free, with small amounts of water and ether. The yield of N-(n-hBptylidenB)-1-aminohydantoin is 14 grams of MP 150°C (with decomposition). This may be recrystal-lized from dimethylformamide. 

The mixture was poured in water, acidified to pH 1 with dilute hydrochloric acid, heated on the steam bath for 30 minutes and then subjected to steam distillation to remove the organic solvents. The residue was filtered, dried and recystallized several times from ethyl acetate. The A -19-nor-17a-ethinylandrosten-17/3-ol-3-one thus obtained had a MP of 198° to 200°C (in sulfuric acid bath), 200° to 204°C (Kofler). 

B) Add to a suspension of 34 g of 3-acetoxy-7-chloro-1,3-dihydro-5-phenyl-2H-1,4-benzo-diazepin-2-one in 80 ml of alcohol, 6 ml of 4N sodium hydroxide. Allow to stand after complete solution takes place to precipitate a solid. Redissolve the solid by the addition of 80 ml of water. Acidify the solution with acetic acid to give white crystals. Recrystallize from ethanol to obtain 7-chloro-1,3-dihydro-3-hydroxy-5-phenyl-2H-1 4-benzodiazepin-2-one, melting point 203°Cto 204°C. 

N-ethyl-3-chloropiperidine was prepared according to the method of Fuson and Zirkle described in Volume 70, J. Am. them. Soc., p 2760. 12.0 g (0.0B1 mol) of N-ethyl-3-chloropiperidine was mixed with 1B.6 g (0.0B1 mol) of benzilic acid and 80 cc of anhydrous isopropyl alcohol as a solvent. The mixture was refluxed for 72 hours. The solution was then filtered and concentrated at 30 mm of mercury. The concentrate was dissolved in water, acidified with hydrochloric acid and extracted with ether to remove the unreacted benzilic acid. 

If it is necessary to use more vigorous materials, such as zinc chloride, any residues must be rinsed away owing to the tendency of zinc chloride to yield a screen of basic chloride in a neutral rinse, a preliminary rinse in water acidified with hydrochloric acid is advisable. 

Preparation ofpure potassium hydrogeniodate. Dissolve 27 g of potassium iodate in 125 mL of boiling water, and add a solution of 22 g of iodic acid in 45 mL of warm water acidified with six drops of concentrated hydrochloric acid. Potassium hydrogeniodate separates on cooling. Filter on a sintered-glass funnel, and wash with cold water. Recrystallise three times from hot water use 3 parts of water for 1 part of the salt and stir continuously during each cooling. Dry the crystals at 100 °C for several hours. The purity exceeds 99.95 per cent. 

In determinations of sulphurous acid and sulphites, excess of standard 0.05M iodine is diluted with several volumes of water, acidified with hydrochloric or sulphuric acid, and a known volume of the sulphite or sulphurous acid solution is added slowly and with constant stirring from a burette, with the jet close to the surface of the liquid. The excess of iodine is then titrated with standard 0.1M sodium thiosulphate. Solid soluble sulphites are finely powdered and added directly to the iodine solution. Insoluble sulphites (e.g. calcium sulphite) react very slowly, and must be in a very fine state of division. 

Aubertein Rehling (Ref 15) have shown that treatment with water at approx 100° causes PETN to hydrolyze. At 125° and under pressure, hydrolysis proceeds quite quickly, and is considerably enhanced by the presence of 0.1% HNO3. Regardless of whether it occurs in water alone or in water acidified with nitric acid, the hydrolysis produces mainly Penta-erythritol Dinitrate. A dil NaOH soln causes PETN to hydrolyze.more rapidly than acidified water. PETN neither reduces Fehling s reagent nor enters into addition products with any aromatic nitro compd. In this respect it differs from both Erythritol Tetranitrate and Nitro-mannitol... 

C, 0.25 nm molecule in the coexistence region between the liquid-expanded and the liquid-condensed (L2) phases (b) BAM image of stearic acid at 22°C, 0.60 nm molecule in the coexistence region between the gas (G) and the hquid-condensed (L2) phases. In each of these images, the polarizer angle has been set to 60°. The subphase is milh-Q water acidified to pH 1.8 with HCl. The scale bar in the lower left of each image is 450 p,m. 

Although chromatographic conditions are extremely variable and widely discussed in the literature, broad trends may nonetheless be perceived. A binary solvent such as acidified water/acidified methanol or acidified water/acidified acetonitrile is primarily used because acidification of the solvent converts nearly all anthocyanidins... 

Hydrocinnamic acid. Reflux a mixture of 53 5 g. of propiophenone (Section IV,137), 20-6 g. of sulphur and 46 g. (46 ml.) of morpholine for 6 horns. Pour the reaction product into 400 ml. of 10 per cent, alcohohc sodium hydroxide solution and reflux for 7 hours. Distil off the alcohol, dilute with water, acidify with hydrochloric acid (to Congo red paper), and extract three times with ether. Wash the ether extracts with water, dry, remove the ether and distil. Collect the hydrocinnamic acid at 125-129°/ 6 mm. it solidifies completely on cooling, m.p. 46-47°. The yield is 39 g. 

Waters Seawater (National Research Council Canada 1992) was collected in the North Atlantic Ocean at a depth of 10 m, 35 km southeast of Hahfax, Nova Scotia, Canada. The water was peristaltically pumped through cleaned polyethylene-hned ethyl vinyl acetate tubing and 0.45-pm acrylic copolymer filters. It was acidified to pH 1.6 with ultrapure nitric acid during its immediate transfer to 50-L acid-leached polypropylene carboys, previously conditioned with ultrapure water acidified to pH 1.6. The seawater was later homogenized in two linked 800-L polyethylene tanks in a clean room and immediately bottled in cleaned 2-L polyethylene bottles. Randomly selected bottles were used for analytical measurements. 

Transfer the residue prepared in Section 6.1.1 or 6.1.2 to a 300-mL separatory funnel with 50 mL of distilled water. Acidify the solution to pH 1 with 2.5 mL of 2N hydrochloric acid and add 10 mL of saturated aqueous sodium chloride. Extract the aqueous mixture twice with 70 mL of ethyl acetate. Combine the extracts and filter into a 500-mL round-bottom flask through 60 g of anhydrous sodium sulfate supported by a plug of cotton wool in a funnel. Evaporate the filtrate to dryness under... 

A method for sediment involves Soxhlet extraction followed by filtration, and concentration to 5 mL. The residue is diluted with water, acidified, extracted with methylene chloride, and then the extracts are dried and evaporated to dryness. The residue is cleaned up on an alumina column. Analysis is performed by GC/NPD. Good recovery (81-97%) and precision (>15% RSD) were reported detection limits were not reported (Muir et al. 1981). 

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