Sulfuric acid preparation

Liquid sulfur dioxide discolors iron, copper, and brass at ca 300 ppm moisture and produces light scale at ca 0.1 wt % moisture and serious corrosion at ca 0.2 wt % or higher moisture content. Copper and brass can be used to handle wet sulfur dioxide where some corrosion can be tolerated, or where the moisture level is low. Wooden tanks are widely used for sulfurous acid preparation, handling, and storage. Sulfite pulp digestors are made of steel lined with acid-resistant brick. 

In attempts to prepare perchromic acid , a mixture of silver (or barium) peroxochromate and 50% sulfuric acid prepared at -80°C reacted explosively on warming to about -30°C. 

Dilute sulfuric acid. Prepare 100 mL of 2.52 MH2S04 from concentrated sulfuric acid. 

The standard directions for the preparation of phenylacetic acid specify that the benzyl cyanide is to be treated with dilute sulfuric acid prepared by adding three volumes of sulfuric acid to two volumes of water. There action, however, goes so vigorously that it is always necessary to have a trap for collecting the benzyl cyanide which is blown out of the apparatus. The use of the more dilute acid, as described in the above directions, is more satisfactory. 

One of the separatory funnels is filled with 1 1. of sulfuric acid prepared by the careful addition of 392 g. (4 moles) (213 cc.) of concentrated sulfuric acid to 213 cc. of water. The other separatory funnel is filled with a solution of 203 g. of commercial sodium cyanide (about 96 per cent) (4 moles) dissolved in sufficient water to make 500 cc. of solution. Evolution of hydrogen cyanide takes place on the simultaneous addition of the two solutions. Practically all of the reaction occurs in the funnel, F, and the sodium bisulfate solution continuously drains into the flask so that fresh solutions are always present. The solution in the funnel remains clear as long as sufficient sulfuric acid is present. An excess of sodium cyanide colors the solution yellow and leads to the formation of a muddy brown precipitate. By adjusting the flow of solutions the rate of evolution is easily controlled, and the preparation requires no attention beyond that involved in the occasional replenishment of the solutions in the separatory funnels. The last part of the hydrogen cyanide can be driven from the apparatus by boiling the bisulfate solution for a few minutes. The yield of acid melting at — r5° to — r4.5° is roo-ro5 g. (93-97 per cent of the theoretical amount) (Notes 3 and 4). 

Wear nitrile rubber gloves, laboratory coat, and eye protection. Avoid breathing dust. Cover spill with a 1 1 1 mixture by weight of sodium carbonate or calcium carbonate, clay cat litter (bentonite), and sand. Scoop mixture into a container of water. Add 3 M sulfuric acid (prepared by cautiously adding 10 mL of concentrated acid to 50 mL of cold water) to neutralize the solution, and then add a further 20 mL for each 1 g of dichromate (to give a pH of 1). While stirring, add sodium thiosulfate crystals until the solution becomes blue colored and cloudy (approximately 10 g/g dichromate). Slowly and cautiously neutralize the solution with sodium carbonate (approximately 3.2 g/mL of 3 M... 

Wear eye protection, laboratory coat, and rubber gloves. Dissolve the aniline (1 mL) in 50 mL of 3 M sulfuric acid (prepared by slowly adding 8 mL of concentrated sulfuric acid to 21 mL of water). Weigh 10 g of potassium permanganate and stir small portions of the solid into the aniline solution over a period of about 1 hour. Stir the mixture at room temperature for 48 hours, and then neutralize the solution by adding solid sodium carbonate or a 10% solution of sodium hydroxide. Add solid sodium bisulfite until solution is colorless. Decant the clear liquid into the drain and discard any brown solid with regular refuse.11,12... 

Small Quantities. To each 5 mL of benzaldehyde to be discarded, add 6 g of potassium permanganate in 100 mL of 3 M sulfuric acid (prepared by adding 17 mL of concentrated sulfuric acid to 83 mL of water). Stir the mixture overnight. Add solid sodium bisulfite until the solution is clear a small quantity of brown precipitate may remain. Neutralize the liquid with 5% aqueous sodium hydroxide and wash into the drain. Discard any brown solid with normal refuse.7... 

To each 9 mg of benzidine, add 10 mL of 0.1 M hydrochloric acid (prepared by slowly adding 1 mL of concentrated acid to 119 mL of cold water). Mix to dissolve. Add 5 mL of 0.2 M potassium permanganate solution (0.3 g of solid potassium permanganate dissolved in 10 mL of water) and 5 mL of 2.0 M sulfuric acid (prepared by carefully adding 1 mL of concentrated acid to 8 mL of cold water). Mix and let stand overnight (at least 10 hours). Decolorize, if necessary, with sodium metabisulfite or ascorbic acid. Neutralize by careful addition of 5 M sodium hydroxide solution (20 g of NaOH dissolved in 100 mL of cold water). Wash the remaining solution into the drain.7... 

Solid. Cover the area of the spill with a 0.3 M solution of potassium permanganate in 3 M sulfuric acid (prepared as for solution spills). Allow to stand overnight. Absorb the liquid residue on a 1 1 1 mixture by weight of soda ash, clay cat litter (bentonite), and sand. Scoop the solid into a container and, in the fume hood, add to a beaker of cold water. If necessary, neutralize the solution by the cautious addition of soda ash. Decant the liquid into the drain with water. Treat the solid as normal refuse.4,5... 

Small Quantities (Red Phosphorus). Add the red phosphorus (5 g) to a solution of potassium chlorate (33 g) in 2 L of 1 N sulfuric acid (prepared by cautiously adding 56 mL of concentrated acid to 1944 mL of cold water) in a 3-L, three-necked, round-bottom flask equipped with water-cooled condenser and heating mantle. Heat the mixture under reflux until all of the phosphorus has dissolved (5-10 hours). When the solution has cooled to room temperature, reduce the excess chlorate by adding about 14 g of sodium bisulfite. Wash the solution into the drain.33... 

Small Quantities. Wear nitrile rubber gloves, eye protection, laboratory coat, and respirator (or work in hood). The selenium salt is dissolved in water and the solution is neutralized by the addition of 1 M NaOH (prepared by dissolving 4 g of NaOH in 100 mL of water) or 1 M sulfuric acid (prepared by cautiously adding 5 mL of concentrated acid to 85 mL of cold water). A 1 M solution of sodium sulfide (prepared by dissolving 7.8 g of Na2S in 100 mL of water) is added to the selenium salt solution and the pH is again adjusted to neutral with 1 M sulfuric acid solution. The precipitate is separated by filtration or decantation. Wash, dry, and recycle or send for disposal in a secure landfill.1 ... 

Wear eye protection, laboratory coat, and nitrile rubber gloves. Prepare a 10% aqueous solution of the waste sodium chlorate. For each 10 mL of solution, slowly, and while stirring, add 44 mL of a 10% solution of sodium bisulfite (this allows about 50% excess of reducing agent). The continued presence of chlorate can be detected by adding, to 3 mL of the solution, a freshly prepared solution of potassium iodide (100 mg) in 3 mL of 3 M sulfuric acid (prepared by cautiously adding 0.5 mL of concentrated acid to 2.5 mL of cold water). An amber to brown color indicates the presence of chlorate. Add sodium bisulfite solution until the test is negative. Neutralize the acidic solution with sodium carbonate and discard into the drain with at least 50 times its volume of water.11 12... 

The residue is cooled to 40° and slowly hydrolyzed (cooling as necessary) with 900 cc. of cold 6 N sulfuric acid, prepared from 145 cc. of concentrated sulfuric acid and 700 cc. of water. The oily layer is separated, washed once with water, and distilled at 60-70° while the pressure is lowered slowly from about 275 mm. to 65 mm. Finally the distillation is continued to 100° and 20 mm. This procedure permits separation of all the crotyl alcohol from the higher-boiling polymerization products. The aqueous layers are combined and distilled until the distillate no longer gives a test for unsaturation with a dilute solution of bromine in carbon tetrachloride. The distillate is then saturated with potassium carbonate, and the oily layer which separates is added to the product obtained by distillation of the oil. 

Note i) in 2300 cc. of ordinary ethyl ether and in B a mixture of 290 g. (4.0 moles) of 95 per cent sodium nitrite, 180 cc. (142 g., 4.5 moles) of methyl alcohol, and 170 cc. of water. In the dropping funnel C is placed 455 cc. of cold dilute sulfuric acid (prepared by adding one volume of concentrated acid to two volumes of water). 

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