Sulfuric acid dilute solution

Ceric sulfate, O.IA Ce(lV) to Ce(lll). Dissolve 63.26 g of cerium(lV) ammonium sulfate dihydrate in 500 mL of 2N sulfuric acid. Dilute the solution to 1 L and standardize against the... 

C. Thymoquinone.—The wet aminothymol thus prepared is immediately dissolved in no cc. of concentrated sulfuric acid diluted to 4 1. and contained in a 12-I. flask. To this solution is added 150 g. of sodium nitrite (2.18 moles), in 5-10-g. portions, with shaking after each addition. The resulting mixture is heated to 60° on a steam bath, with occasional shaking, for half an hour (Note 5), and is then distilled in a current of steam, by means of the apparatus described in Org. Syn. 2, 80 (Note 6). All the thymoquinone passes over with the first 3 1. of distillate it solidifies on cooling, and is filtered with suction (Note 7), washed, and dried at room temperature. The yield is 80-87 g. (73-80 per cent of the theoretical amount) of bright yellow crystals, melting at 43-45° (Note 8). 

The residue (12 g) which contains the 18-iodo-18,20-ether is dissolved in 200 ml of acetone, 5 g of silver chromate is added Note 3) and after cooling to 0°, 11.8 ml of a solution of 13.3 g of chromium trioxide and 11.5 ml of concentrated sulfuric acid, diluted to 50 ml with water is added during a period of 5 min. After an additional 60 min, a solution of 112 g of sodium acetate in 200 ml of water is added and the mixture diluted with benzene (400 ml), filtered and the benzene layer separated. The aqueous phase is reextracted with benzene, washed with half-saturated sodium chloride solution, dried and evaporated to yield 11.2 g of a crystalline residue. Recrystallization from ether gives 7.2 g (72%) of pure 3/5, 1 la, 20/5-trihydroxy-5a-pregnan-18-oic acid 18,20 lactone 3,11-diacetate mp 216-218°. 

All the flexible polyquinolines are readily soluble in chlorinated hydrocarbons such as methylene chloride and chloroform. Semirigid polyquinolines are soluble in tetrachloroethane or / /-cresol, but rigid polyquinolines are soluble only in strong acids like sulfuric and trifluoromethane sulfonic acid. Dilute solution properties of polyquinolines have been investigated by techniques such as membrane osmometry, light scattering, viscometry, and gel-permeation chromatography (96,97). 

V vs. Ag/AgCl in acid has been described [132]. The assay requires the extraction of the compound from a tablet into the 0.5 M sulfuric acid, dilution, and direct polarographic assay of an aliquot of this solution. The assay is accurate, sensitive, and, since it does not require the removal of insoluble matter, more rapid than the spectrophotometric procedures. 

To a round-bottomed flask (50 ml) equipped with a long-necked adapter, reflux condenser, and a magnetic stirrer bar, add ethylene chloride (2.1 ml), Aliquat (0.10 g, 0.25 mmol), sodium tungstate dihydrate (0.14 g, 0.72 mmol), phosphoric acid (40% solution)(0.17 g, 1.72 mmol), and adjust pH of the solution to ca. 1.6 with a diluted sulfuric acid (30% solution). 

Potassium nitrocarbamate (9.1 g.) is weighed on glazed paper and, with the aid of a porcelain or platinum spatula, is added in very small portions to the cold dilute sulfuric acid. The solution is swirled continuously. Whenever the ice melts, the flask is immersed in the cold bath until ice again forms. 

Standard Preparations Dissolve 338.5 mg of mercuric chloride, in about 200 mL of water in a 250-mL volumetric flask, add 14 mL of 1 2 sulfuric acid, dilute to volume with water, and mix. Pipet 10.0 mL of this solution into a 1000-mL volumetric flask containing about 800 mL of water and 56 mL of 1 2 sulfuric acid, dilute to volume with water, and mix. Pipet 10.0 mL of the second solution into a second 1000-mL volumetric flask containing 800 mL of water and 56 mL of 1 2 sulfuric acid, dilute to volume with water, and mix. Each milliliter of this diluted stock solution contains 0.1 pig of mercury. Pipet 1.25, 2.50, 5.00, 7.50, and 10.00 mL of the last solution (equivalent to 0.125, 0.250, 0.500, 0.750, and 1.00 ptg of mercury, respectively) into five separate 150-mL beakers. Add 25 mL of aqua regia to each beaker, cover with watch glasses, heat just to boiling, simmer for about 5 min, and cool to room temperature. Transfer the solutions into separate 250-mL volumetric flasks, dilute to volume with water, and mix. Transfer a 50.0-mL aliquot from each solution into five separate 150-mL beakers, and add 1.0 mL of 1 5 sulfuric acid and 1.0 mL of a filtered solution of 1 25 potassium permanganate solution to each. Heat the solutions just to boiling, simmer for about 5 min, and cool. 

Ferrous Sulfate Solution Dissolve 44 g of ferrous sulfate (FeS04-7H20) in ] N sulfuric acid, dilute to 100 mL with 1 N sulfuric acid, and mix. Use within 5 days of preparation. 

Standard Arsenic Solution Accurately weigh 132.0 mg of arsenic trioxide that has been previously dried at 105° for 1 h, and dissolve it in 5 mL of a 1 5 sodium hydroxide solution. Neutralize the solution with 2 N sulfuric acid, add 10 mL in excess, and dilute to 1000.0 mL with recently boiled water. Transfer 10.0 mL of this solution into a 1000-mL volumetric flask, add 10 mL of 2 N sulfuric acid, dilute to volume with recently boiled water, and mix. Use this final solution, which contains 1 pig of arsenic in each milliliter, within 3 days. 

Finally must be mentioned the interesting halochrome reaction of C-curarine similar color reactions are given by those derivatives of C-curarine which retain the chromophore of the parent molecule. This reaction has been studied most closely with tetrahydronorcurarine. In 40-80% aqueous sulfuric acid, the base dissolves to give a deep-violet solution. In concentrated sulfuric acid, the solution is yellow but, on dilution with water to 70%, the color becomes deep-violet and finally disappears on further dilution. Tetrahydronorcurarine can be recovered unchanged from these diluted acid solutions. A plausible explanation of... 

A solution of 200 g. (1.03 moles) of a-methyl-d-mannoside (Org. Syn. Coll. Vol. 1, 1st Ed. (1932), p. 362 2nd Ed. (1941), p. 371) in 3.2 1. of 2 N sulfuric acid (178 cc. concentrated sulfuric acid diluted to 3.2 1.) is steam-distilled from a 5-1. flask for one hour. The flask is heated externally during this time so that the volume of the solution remains constant. The mixture is transferred to a 2- or 3-gal. crock, 10 g. of decolorizing charcoal (Norite) is added, and the solution is rapidly stirred while it is neutralized (litmus) by the addition of barium carbonate (Note 1). 

Hydrated magnesium silicate (Talc, 3Mg0 4Si02 H20, CAS No. 14807-96-6) is a magnesium silicate commonly referred to as "soapstone". It is obtained from natural sources and may contain a small amount of aluminum silicate. It is composed of MgO (31.7%), Si02 (63.5%), and H2O (4.8%). It is a crystalline nonhygroscopic, odorless, tasteless powder which is practically insoluble in water, dilute mineral acids, dilute solutions of alkali halides, and alkaline hydroxides but is soluble in hot concentrated sulfuric acid. 

Chromium trioxide [chromium(VI) oxide, chromic add, or chromic anhydride], Cr03 (dark red crystals, mp 195 °C), is one of the most powerful and universal oxidants. It is applied in solutions in acetic acid, dilute sulfuric acid, a mixture of acetic acid and dilute sulfuric acid, dilute sulfuric acid and acetone (Jones reagent), acetic anhydride and acetic acid (Fieser reagent) [535], water, water and ether [536,537,535], dichloromethane [539],... 

In sulfuric acid production, acid brick lining of membrane coated mild steel tanks and reaction vessels is considered the most durable and versatile construction material for the sulfuric acid plant. Such linings wiil reduce the steel shell temperature and prevent erosion of the normally protective iron sulfate film that forms in stagnant, concentrated (oxidizing) sulfuric acid. Dilute (red uC ing) sulfuric acid solutions are very corrosive to carbon steel, which must be protected by impermeable (e.g., elastomeric) membranes and acid brick lining systems. Such acid brick linings often employ membranes comprising a thin film of Teflon or Kynar sandwiched between layers of asphalt mastic. 

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