Acetic acid solution preparation

Barfoed s reagent Is prepared by dissolving 13-3 g. of crystallised neutral copper acetate in 200 ml. of 1 per cent, acetic acid solution. The reagent does not keep well. 

Diphenic acid. Phenanthrene upon oxidation in acetic acid solution at 85° with 30 per cent, hydrogen peroxide gives diphenic acid (diphenyl-2 2 -di-carboxyHc acid) no phenanthraquinone is formed under these experimental conditions. The reaction is essentially an oxidation of phenanthrene with peracetic acid. (For another method of preparation, see Section I V,74.)... 

Dibromofluorescein is prepared by treating fluorescein in 80 per cent, acetic acid solution with the theoretical quantity of bromine. 

According to the literature, the product obtained in this manner may contain ethyl adipate. To remove this, the product is cooled to 0° and run slowly into 600 cc. of 10 per cent potassium hydroxide solution maintained at 0° with ice-salt. Water is added until the salt which separates has dissolved, and the cold alkaline solution is extracted twice with 200-cc. portions of ether. The alkaline solution, kept at 0°, is run slowly into 900 cc. of 10 per cent acetic acid solution with stirring, the temperature remaining below 1° (ice-salt). The oil which separates is taken up in 400 cc. of ether, and the aqueous solution is extracted with four 250-cc. portions of ether. The ether extract is washed twice with cold 7 per cent sodium carbonate solution and dried over sodium sulfate. After removal of the ether the residue is distilled, b.p. 7g-8i°/3 mm. The recovery is only 80-85 per cent, and in a well-conducted preparation the ethyl adipate eliminated amounts to less than one per cent of the total product. Unless the preparation has proceeded poorly the tedious purification ordinarily is best omitted. 

Cholestanone has been prepared by the oxidation of dihydro-eholesterol with chromic anhydride in acetic acid solution.1 The yield is sometimes diminished as a result of the partial acetylation of the sterol. 

Pentaerythrityl bromide has been prepared by the action of phosphorus tribromide on pentaerythritol, - and of an acetic acid solution of hydrobromic acid on pentaerythritol tetraacetate. The iodide has been prepared by the action of red phosphorus and hydriodic acid on pentaerythritol and by treating the bromide with sodium iodide in acetone. ... 

A solution of 85.8 g (0.2 moles) of 3/ -acetoxy-27-norchoIest-5-en-25-one in 500 ml of anhydrous thiophen-free benzene is added to a Grignard solution prepared from 24.3 g (1 g-atom) of magnesium and 149 g (1.05 moles) of freshly distilled methyl iodide in 575 ml of anhydrous ether. The mixture is refluxed for 3 hr and allowed to stand overnight. After cooling to 5° the complex is decomposed by the slow addition of 200 ml of ice water and 400 ml of 50% acetic acid solution, and steam distilled until no more oil passes over. The residual product is filtered, washed with water and dried at 80°. Crystallization from methanol gives 70 g (87%) of cholest-5-ene-3)5,25-diol mp 179.5-181°. The analytical sample melts at 181.5-182.5° [a]o —39° (CHCI3). 

Type 5 tellurenyl bromides are not easily accessible. They were prepared by refluxing an acetic acid solution of tellurium dibromides 6 in the presence of catalytic amounts of HBr [96ZOK1434 97JOM(536-537)233]. The reaction is not easily reproducible, affording the tellurenyl bromides in rather low yields. 

At the same, time attempts to apply this approach to the synthesis of phenotel-lurazine and its A-methyl derivative using diphenylamine and A-methyldiphenyl-amine as starting materials failed [83JOM(251)223 85KGS757]. The parent phe-notellurazine 35 (M = NH, R = R = H) has been prepared in low yield (7%) by refluxing an acetic acid solution of 4-trichlorotellurodiphenylamine 39 (89H1007). 

Dihydrocarvone, Cj Hj O, is found to a small extent in oil of caraway, and can be prepared by the oxidation of dihydrocarveol by chromic acid in acetic acid solution. The ketone has the constitution —... 

Hydrolysis of the acetate ester with alkali, e.g., sodium methoxide in methanol, affords the free alcohol, 16/3-methyl-1,4,9( 11 )-pregnatriene-17o, 21-diol-3,20-dione. To a suspension of 3 grams of 16/3-methyl-1,4,9(11)-pregnatriene-17o,21-diol-3,20-dione-21-acetate in 40 ml of acetone is added at 0°C with stirring 2 grams of N-chlorosuccinimide and then 7 ml of a perchloric acid solution prepared by dissolving 0.548 ml of 70% perchloric acid in 33 ml of water. The resulting reaction mixture is stirred at 0°C for about 4 hours 45 minutes. 

Sodium acetate-acetic acid buffer. Prepare a solution which is 0.2 M in sodium acetate and 0.8 M in acetic acid. The pH is 4.0. 

The multiple emulsion technique includes three steps 1) preparation of a primary oil-in-water emulsion in which the oil dispersed phase is constituted of CH2CI2 and the aqueous continuous phase is a mixture of 2% v/v acetic acid solution methanol (4/1, v/v) containing chitosan (1.6%) and Tween (1.6, w/v) 2) multiple emulsion formation with mineral oil (oily outer phase) containing Span 20 (2%, w/v) 3) evaporation of aqueous solvents under reduced pressure. Details can be found in various publications [208,209]. Chemical cross-linking is an option of this method enzymatic cross-linking can also be performed [210]. Physical cross-linking may take place to a certain extent if chitosan is exposed to high temperature. 

Nineteen bone samples were prepared for analysis of the trace elements strontium (Sr), rubidium (Rb), and zinc (Zn). The outer surface of each bone was removed with an aluminum oxide sanding wheel attached to a Dremel tool and the bone was soaked overnight in a weak acetic acid solution (Krueger and Sullivan 1984, Price et al. 1992). After rinsing to neutrality, the bone was dried then crushed in a mill. Bone powder was dry ashed in a muffle furnace at 700°C for 18 hours. Bone ash was pressed into pellets for analysis by x-ray fluorescence spectrometry. Analyses were carried out in the Department of Geology, University of Calgary. 

During preparation of the IV-nitroso derivative from the lactam in acetic acid solution, the treatment with dinitrogen trioxide must be very effectively cooled to prevent explosive decomposition. 

Prepare four or five similar wet mounts and examine them as described above. To. each slide, immediately add 2 drops of 1% acetic acid solution and mix it well (microfilariae will be killed and straightened). Allow the slide to air dry. 

They prepared the acetate by means of acetic anhydride in dry pyridine and purified it by separation from an acetic acid solution to which warm methyl alcohol had been added n ]n2 = — 22.70° (c = 10, acetic acid), m. p. 206-208°. In the presence of barium hydroxide irisin formed an insoluble product whose composition was represented by 6(C6Hi0O6)-Ba(OH)2. In contrast to inulin, these authors found that Takadiastase at pH 5 to 5.5 did not hydrolyze irisin. 

A student prepared a 1.00 M acetic acid solution (HC2H302). The student found the pH of the... 

Prepare a 1.0M acetic acid solution by adding 1.7 mL of 6.0M acetic acid to 8.3 mL of distilled water in the 10-mL graduated cylinder. Empty the 10 mL of diluted acid into the rinsed 50-mL beaker. After mixing, transfer 3 mL of the... 

Nickel sulfide is mined directly from natural deposits. Also, it can be prepared in the laboratory by precipitation from an aqueous solution of a nickel salt with ammonium sulfide, (NH4)2S, or by precipitation from an acetic acid solution with hydrogen sulfide. While the aqueous solution method yields an amorphous product (alpha-NiS) which rapidly changes on exposure to air and contact with the solution to a brown crystalline sulfide (beta-NiS), the acid solution method forms only crystalline beta-NiS. 

Potassium acetate is prepared by addition of potassium carbonate in a small volume of water to acetic acid solution, followed by evaporation and... 

I litre of 0.1 M sodium acetate buffer with a pH 4.0 is required. Molecular weight of acetic acid = 60 there litre of 0.1 M buffer there will be 6 g of acetic acid. To prepare the buffer 6 g of acetic acid are weighed a made up to ca 500 ml with water. The pH of the acetic acid solution is adjusted to 4.0 by addition of 2 M hydroxide solution using a pH meter to monitor the pH. The solution is then made up to 1 lifre with watei Calculate the concentration of acetate and acetic acid in the buffer at pH 4.0. 

If difficulties are encountered in filtering the hot acetic acid solution through filter paper, an asbestos filter may be prepared and used to advantage. 

Dihydroxo-diaquo-diammino-chromic Chloride, [Cr(NH3), (H20)2(OH)2]Cl, is formed by the addition of ammonia or pyridine to an aqueous solution of tetraquo-diammino-chloride, or saturating an aqueous acetic acid solution with rubidium chloride. It forms light red violet crystals which are insoluble in water. The iodide is obtained from the bromide on addition of potassium iodide to a dilute acetic acid solution of the salt as a light red violet precipitate. The thiocyanate, [Cr(NH3)2(H20)2(OH)2]SCN, is amorphous, and is prepared from the bromide by dissolving in aqueous acetic acid and adding potassium thiocyanate. 

Acetic acid is a weak organic acid whose molecular formula is written as CH3COOH. If an 800 mL aqueous solution of acetic acid is prepared by dissolving 4.8 g of acetic acid ... 

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