Hydrochloric acid preparation

Add the salt to dilute hydrochloric acid (prepared from 28 ml. of the concentrated acid and 150 ml. of water) contained in a 500 ml. flask fitted with a reflux condenser. Warm the mixture gently carbon dioxide is evolved and an oil separates. Heat on a steam bath for 90 minutes, cool, and extract the oil with 75 ml. of benzene. Wash the extract with 100 ml. of water, and distil the benzene solution under reduced pressure from a Claisen flask. Collect the a-phenylpropionaldehyde at 90-93°/10 mm. the yield is 30 g. 

Dilute hydrochloric acid prepared by Arabian alchemist Rhazes... 

The salt is added to a dilute solution of hydrochloric acid prepared by mixing 300 ml. of water and 56 ml. of concentrated acid (sp. gr. 1.18) the acid should be contained in a 1-1. flask under a reflux condenser. The mixture is warmed gently, whereupon carbon dioxide is evolved and an oil separates. The flask is heated on a steam bath for 1.5 hours, and the oil is then extracted... 

Another chemist who just missed discovering bromine was J. R. Joss, who in 1824, and again in January, 1826, had recorded in his laboratory notes the appearance of a red color in some hydrochloric acid prepared from gray Hungarian rock salt and Bohemian fuming sulfuric acid. At the time, he attributed this color to the possible presence of selenium from the sulfuric acid. After Balard s discovery, however, he made further experiments with the same materials and became convinced that the red color must be due to bromine. His attempts to obtain more of the bromine-containing rock salt were unsuccessful (147). 

In a 4-1. beaker equipped with a stirrer which can be operated above the liquid level to break the foam are placed 250 ml. of 12 N hydrochloric acid and 250 ml. of water. The filtrate obtained above is cooled to about 50° and is added to the hydrochloric acid in small portions and at such a rate that the mixture does not foam over. If efficient stirring is used in the foam layer, this addition can be carried out in 5 minutes. The product is isolated by filtration through a Buchner funnel and is washed on the filter, first with a 250-ml. portion of dilute hydrochloric acid (prepared by diluting 50 ml. of 12 N hydrochloric acid to about 250 ml.) to remove anthranilic acid, and then with 500 ml. of water. The product is sucked as dry as possible and is then spread in a thin layer and allowed to air dry for about 15 hours. When easily pulverizable, the material is transferred to an oven and dried for 3 hours at 100-120°. 

Forty-seven grams (48 ml., 0.5 mole) of aniline is dissolved in 200 ml. of aqueous hydrochloric acid (prepared from equal volumes of concentrated acid and water) in a 2-1. beaker. The beaker is equipped with a mechanical stirrer and immersed in an ice-salt bath. After the solution has cooled to 5°, 36 g. (0.52 mole) of sodium nitrite dissolved in 1 1. of water is added slowly, with stirring, from a separatory funnel. The tip of the stem of the separatory funnel should dip well below the surface of the liquid. The rate of addition is adjusted to maintain the temperature below 10°. A drop of the reaction mixture is tested from time to time with starch-iodide paper (Note 2). The sodium nitrite solution is added until nitrous acid persists in the solution during a 5-minute interval. 

Stop mixing, take pH (range 3.1 to 3.3). If necessary, adjust with 10% sodium hydroxide or 10% hydrochloric acid (prepared by adding 1 mL hydrochloric acid, reagent grade, with 3.3 mL purified water). Mix. 

Small Quantities. Wear nitrile rubber gloves, laboratory coat, and eye protection. Work in the fume hood. To decompose 10 mL (11 g) of acetyl chloride, place 160 mL of a 2.5 M sodium hydroxide solution (prepared by dissolving 16 g of NaOH in 160 mL of water) in a 250 mL, three-necked, round-bottom flask equipped with a stirrer, dropping funnel, and thermometer. Add the acetyl chloride to the dropping funnel and run it dropwise into the stirred solution at such a rate that the temperature does not rise above 35°C. Continue to stir at room temperature overnight. Neutralize the solution to pH 7 with 2 M hydrochloric acid (prepared by cautiously adding 40 mL of concentrated acid to 200 mL of cold water) and wash into the drain with at least 50 times its volume of water.10... 

Wear nitrile rubber gloves, laboratory coat, and eye protection. Work in the fume hood. Cover the hydride with a 1 1 1 mixture by weight of sodium or calcium carbonate, clay cat litter (bentonite), and sand. Mix carefully. Place material in a large container behind a safety shield in the hood. Slowly add dry butyl alcohol (31 mL per gram of aluminum hydride). After reaction ceases, slowly and cautiously add water (three times the volume of alcohol added). Neutralize with 6 M hydrochloric acid (prepared by adding concentrated acid to an equal volume of cold water), and let stand until solids settle. Decant the liquid into drain and discard the solid residue as normal refuse.7,8... 

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... 

Wear leather gloves, goggles, heavy face shield, and laboratory coat. Work from behind body shield. Avoid unnecessary heat, friction, or impact. Mop up with wet paper towels. In the fume hood and behind a shield, place paper towels in a beaker containing 6 M hydrochloric acid (prepared by adding concentrated acid to an equal volume of cold water about 150 mL for each 1 g of azide). Follow waste disposal procedure.2... 

The residual nickel is suspended in 200 mL of water in a 2-L, three-necked, round-bottom flask, and 800 mL of 1 N hydrochloric acid (prepared by slowly adding 66 mL of concentrated acid to 734 mL of cold water) is added gradually while stirring. Continue stirring until the nickel has dissolved. The solution is slowly basified with sodium hydroxide to precipitate nickel hydroxide. Collect the precipitate and package it for recycling or disposal in a secure landfill. Wash the aqueous solution into the drain.4... 

Potassium Cyanide Solutions. Wear breathing apparatus, eye protection, laboratory coat, and butyl rubber gloves. Instruct others to keep a safe distance. Cover the spill with a 1 1 1 mixture by weight of sodium carbonate or calcium carbonate, clay cat litter (bentonite), and sand. Scoop the mixture into a container and transport to the fume hood. Slowly, and while stirring, add the slurry to a pail containing household bleach (about 70 mL/g of cyanide). Test the solution for the presence of cyanide using the Prussian blue test. To 1 mL of the solution, add 2 drops of a freshly prepared 5% aqueous ferrous sulfate solution. Boil the mixture for at least 60 seconds, cool to room temperature and add 2 drops of 1 % ferric chloride solution. Add 6 M hydrochloric acid (prepared by... 

Small Quantities. Wear eye protection, laboratory coat, and butyl rubber gloves. Work in the fume hood. Slowly add sodium alkoxide to a pail of water. Neutralize with 6 M hydrochloric acid (prepared by cautiously adding a volume of concentrated acid to an equal volume of cold water), and then wash into the drain.5... 

Distillation-Reducing Solution Dissolve 36 g of ACS low-arsenic ferrous chloride (FeCl2-4H20) in 500 mL of 6.6 N hydrochloric acid. Prepare fresh on the day of use. 

Standard Curve Transfer 100.0 mg of L-tyrosine, chromatographic-grade or equivalent (Aldrich Chemical Co.), previously dried to constant weight, to a 1000-mL volumetric flask. Dissolve in 60 mL of 0.1 N hydrochloric acid. When completely dissolved, dilute the solution to volume with water, and mix thoroughly. This solution contains 100 pig of tyrosine in 1.0 mL. Prepare three more dilutions from this stock solution to contain 75.0, 50.0, and 25.0 pig of tyrosine per mL. Determine the absorbance of the four solutions at 275 nm in a 1-cm cell on a suitable spectrophotometer versus 0.006 N hydrochloric acid. Prepare a plot of absorbance versus tyrosine concentration. 

Acid/Alkali wash. To remove mineral scales and metal salt precipitates from the membrane surface, washing with a 1.0% solution of citric acid (or hydrochloric acid) prepared in 25 L of DM water was carried out at a pressure of 10 bar for a 10 min... 

When the reaction has ceased and practically all the magnesium has reacted, immerse the tube in a beaker containing water and ice. Add very slowly 5 ml dilute hydrochloric acid prepared by the addition of 3 ml concentrated acid to 5 g of ice. The dilute acid can be added by means of a pipette dropper, by removing the calcium chloride tube and using the opening to insert the dropper. When the decomposition of the reagent is complete, the aqueous layer should be clear. If it is milky or cloudy, or if undissolved magnesium is present, add a few drops of concentrated hydrochloric acid and allow the reaction to proceed for a few minutes. 

Dickey (113) has discussed in detail the preparation of specific silicas by precipitating the silica in the presence of the specific compound. Of the various procedures described by Dickey, the hydrochloric acid preparation seems to give best results. The procedure of Polyakov for preparing specific silicas is based on drying the silica in an atmosphere of the specific compound (108,115). The specificity of these adsorbents appears to be less pronounced than in the case of adsorbents prepared by Dickey s procedure, and Polyakov s technique is limited to volatile specific compounds. The Dickey procedure cannot be applied to compounds which are not water soluble, but for such substances the procedure of Patrikeev and Sholin (109) can be used After precipitation of the silica without added specific compound, the adsorbent is washed with methanol and allowed to finish gelling in the presence of a methanol solution of the specific compound. The preparation of specific aluminas (722) and silica-aluminas (114) has also been described. 

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