Sulfuric acid mixtures with water

In a 500 cc. round-bottom flask are placed 240 g. of hydro-bromic acid (48 per cent), 62 g. of concentrated sulfuric acid, and 71 g. of M-oclyl alcohol (b. p. 135-140° at 100 mm.). The mixture is boiled under reflux for three and a half hours. The solution is diluted with water and the bromide layer is separated, washed once with a little cold concentrated sulfuric acid, then with water and finally with dilute sodium carbonate solution, The crude yield is 102 g. this is dried over a little calcium chloride and distilled. The product is collected at iyh 200" and amounts to 96 g. (91 per cent theory). 

The Extrelut cleanup method is suitable for most foodstuffs, such as cheese, yogurt, and other samples that tend to form emulsions during extraction. The prepacked or refilled Extrelut column in a plastic tube consists of a wide-pore kieselgel column. A sample is homogenized in 0.5 N sulfuric acid, diluted with water, and applied onto the Extrelut column for at least 15 min. The absorbed preservatives are eluted with a chloroform - isopropanol (9 1) mixture, and the elu-ate is collected and evaporated carefully nearly to dryness. The last few milliliters of solvent are removed with a gentle flow of nitrogen to prevent substantial losses of BA and SA, which have relatively high vapor pressures. The residue is transferred with methanol into a 10-ml volumetric flask and diluted to volume with methanol. To speed up the dissolution, the use of an ultrasonic bath is recommended. The filtered extract is analyzed on a /zBondaPak Cl8 column, with a... 

Summary 70% Nitric acid can be obtained by treating potassium or sodium nitrate with sulfuric acid, mixing with water, and then extracting the acid mixture with methylene chloride. The result is a methylene chloride solution containing 99% nitric acid. This methylene chloride/99% nitric acid solution is then mixed with a calculated amount of water, and then carefully distilled to remove the methylene chloride and leave behind 70% nitric acid. 

A warm solution of 600 g. of technical sodium dichromate in 800 ml. of glacial acetic acid and 200 ml. of water is added dropwise (30 minutes) to a rapidly refluxing solution of 200 g. (1.2 moles) of technical fluorene in 400 ml. of glacial acetic acid. The mixture is refluxed for an additional 2.5 hours, after which it is poured into 4 1. of ice water and allowed to stand for 2 hours. The precipitated solid is filtered off and washed first with dilute sulfuric acid then with water until free of chromate ion. The air-dried product (190-200 g.)... 

One-third of the cold nitric-sulfuric mixture is placed in each of three 500-cc. Erlenmeyer flasks (Note 3), and each portion is treated separately with one-third of the methyl alcohol-sulfuric acid mixture, with constant shaking and thorough mixing (Note 4). The temperature is allowed to rise fairly rapidly to 40° and kept at this point by external cooling. During the addition of the methyl alcohol-sulfuric acid, most of the ester separates as an almost colorless oily layer above the acid. The time required for completion of the reaction is two to three minutes for each flask. The reaction mixtures are allowed to stand in the cold for an additional fifteen minutes but not longer. The lower layer of spent acid is separated promptly and poured at once into a large volume of cold water (about i 1. for each portion) to avoid decomposition which quickly ensues with copious evolution of nitrous fumes. 

CHLOROMETHYL OXIRANE (106-89-8) C3H5CIO Highly flammable, polymerizable liquid. Forms explosive mixture with air [explosion limits in air (vol %) 3.8 to 21.0 flash point 69°F/21°C 88°F/31 °C autoignition temp 772 F/411 °C Fire Rating 3]. Reacts violently with water. Contact with elevated temperatures, contamination, strong acids, strong bases, metallic halides, aluminum, aluminum chloride iron(III) chloride and other chlorides of iron or zinc can cause explosive polymerization. Violent reaction with aniline, hypochlorite, isopropylamine, potassium ieri-butoxide (ignition), sulfuric acid. Mixtures with trichloroethylene forms explosive dichloroacetylene. Incompatible with aliphatic amines, alkaline earths, alkali... 

Dry nitrocellulose, which bums rapidly and furiously, may detonate if present in large quantities or if confined. Nitrocellulose is a dangerous material to handle in the dry state because of sensitivity to friction, static electricity, impact, and heat. Nitrocellulose is always shipped wet with water or alcohol. The higher the nitrogen content the more sensitive it tends to be. Even nitrocellulose having 40% water detonates if confined and sufftcientiy activated. AH large-scale processes use nitric—sulfuric acid mixtures for nitration (127—132). 

The oxidation of teUurium(IV) by permanganate as an analytical method has been studied in some detail (26). The sample is dissolved in 1 1 nitric-sulfuric acid mixture addition of potassium bisulfate and repeated fuming with sulfuric acid volatilises the selenium. The tellurite is dissolved in 10 vol % sulfuric acid, followed by threefold dilution with water and titration with potassium permanganate ... 

Impurities can sometimes be removed by conversion to derivatives under conditions where the major component does not react or reacts much more slowly. For example, normal (straight-chain) paraffins can be freed from unsaturated and branched-chain components by taking advantage of the greater reactivity of the latter with chlorosulfonic acid or bromine. Similarly, the preferential nitration of aromatic hydrocarbons can be used to remove e.g. benzene or toluene from cyclohexane by shaking for several hours with a mixture of concentrated nitric acid (25%), sulfuric acid (58%), and water (17%). 

A 8 A solution of chromic acid is prepared by dissolving 26.72 g of chromium trioxide in a mixture of 23 ml of concentrated sulfuric acid and enough water to make the total volume of the solution 100 ml. Rapid dropwise addition of a slight excess of this reagent to an acetone solution (2 % or less) of the hydroxy steroid at room temperature or below with stirring usually results in complete conversion to ketone in less than 10 min. The product is isolated by dilution with water followed by filtration or extraction. 

E) Preparation of 2-( 1-Succinyloxyethyl)-3-Methyl-5-(2-Oxo-2,5-Dihydro-4-Furyl)Bemo[b] -Furan (409 CBj 8.65 grams of compound 3574 CB in 43 ml of pyridine are warmed for 30 minutes, on a water bath, with succinic anhydride. At the end of this, the pyridine is stripped off in vacuo. The mixture is treated with dilute sulfuric acid and with ether, the crystalline product filtered off, washed with water and with ether, and recrystallized from ethyl acetate (9.35 grams). MPq = 144°C (measured after drying at 90°C and 0.1 mm). Yield 77%. The product yields an equimolecular compound with morpholine. MPc= 136°C (from ethyl acetate). 

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