EXOTHERMIC REACTION MIXTURES

Hydroxy- 6-diazoandrost-5-en- l-one (96) To a stirred solution of 750 ml of methanol and 144 ml of 5 A sodium hydroxide is added 36 g (0.114 mole) of oximino ketone. Concentrated aqueous ammonia (56.6 ml, 0.850 mole) is then added followed by dropwise addition of 265 ml of cold 3 M sodium hypochlorite at a rate sufficient to maintain the temperature of the exothermic reaction mixture at 20 + 1° while cooling with an external ice bath. At temperatures below 20° appreciable amounts of a-mono- and a-dichloro ketones are obtained above 20° the chloramine decomposes before reacting with the oximino ketone. As soon as all of the sodium hypochlorite has been added, the ice bath is removed and the reaction mixture is allowed to warm to room temperature with continued stirring for 6 hr. The reaction mixture is diluted with an equal volume of water and extracted twice with... 

The haloalkane (67 mmol) is added to a stirred mixture of the phenylacetonitrile (20 mmol), sulphur (1.0 g, 31 mmol), TEBA-Cl (0.1 g, 0.4 mmol), and DMSO (1.0 ml) in aqueous NaOH (50%, 10 ml) at 45°C. The exothermic reaction mixture is stirred for 75 min and then diluted with H20 (25 ml) and extracted with PhH (2 x 25 ml). The organic extracts are dried (MgS04) and fractionally distilled to yield the thioether. 

CA 60, 9044(1964) (Exothermic reaction mixtures for underwater propulsion and ignition devices contg alkali metal perchlorates and powdered Al, Be or Mg are improved in regard to their burning rates and pressure stability by incorporating ca, 1% of finely divided Fe) Ad 119) Dy-namit-Nobel AG, BelgP 627561(1963) ... 

Exothermic reaction mixtures for underwater propulsion and ignition devices 6 E349... 

A mixture of 10 g N-methylformanilide and 10 g POCl3 was heated on the steam bath for 10 min producing a deep claret color. To this there was added 5.1 g of l,4-dimethoxy-2-(i)-propoxybenzene, and the immediately exothermic reaction mixture was heated on the steam bath for 45 min. It was then poured into 800 mL H20 which was stirred until the dark oil changed into loose, light-colored solids. These were removed by filtration giving 5.7 g of an amber crystalline product with... 

EXOTHERMIC REACTION MIXTURES IN STEEL MAKING Babaitsev, I. V. etal., Chem. Abs., 1987, 107, 138866... 

To a 21.7 g sample of 2-ethylanisole, well stirred but without solvent, there was added, 1 mL at a time, 21 mL of chlorosulfonic acid. The color progressed from white to yellow, and finally to deep purple, with the evolution of much HCI. The exothermic reaction mixture was allowed to stir until it had returned to room temperature (about 0.5 h). It was then poured over 400 mL cracked ice with good mechanical stirring, which produced a mass of pale pink solids. These were removed by filtration, washed well with H20, and air dried to give about 27 g of 3-ethyl-4-methoxybenzenesulfonyl chloride as an off-white solid that retained some H20. A sample recrystallized from cyclohexane had a mp of 44-46 °C. A sample treated with ammonium hydroxide provided white crystals of 3-ethyl-4-methoxybenzenesulfonamide which could be recrystallized from H20 to give tufts of crystals with a mp of 97-98 °C. Anal. (C9H13N03S) C,H. 

What is the effect of increasing the temperature of an exothermic reaction mixture at equilibrium Of decreasing the temperature ... 

Increasing the temperature of an exothermic reaction mixture at equilibrium causes the reaction to shift left, absorbing some of the added heat. Decreasing the temperature of an exothermic reaction mixture at equilibrium causes the reaction to shift right, releasing heat. 

Fit a 1500 ml. bolt-head flask with a reflux condenser and a thermometer. Place a solution of 125 g. of chloral hydrate in 225 ml. of warm water (50-60°) in the flask, add successively 77 g. of precipitated calcium carbonate, 1 ml. of amyl alcohol (to decrease the amount of frothing), and a solution of 5 g. of commercial sodium cyanide in 12 ml. of water. An exothermic reaction occurs. Heat the warm reaction mixture with a small flame so that it reaches 75° in about 10 minutes and then remove the flame. The temperature will continue to rise to 80-85° during 5-10 minutes and then falls at this point heat the mixture to boiling and reflux for 20 minutes. Cool the mixture in ice to 0-5°, acidify with 107-5 ml. of concentrated hydrochloric acid. Extract the acid with five 50 ml. portions of ether. Dry the combined ethereal extracts with 10 g. of anhydrous sodium or magnesium sulphate, remove the ether on a water bath, and distil the residue under reduced pressure using a Claiseii flask with fractionating side arm. Collect the dichloroacetic acid at 105-107°/26 mm. The yield is 85 g. 

The amines are comparatively weak bases, so that a certain amount of free amine will be produced by salt hydrolysis unless an excess of acid is present. The reaction mixture must be kept very cold during the process (which is exothermic in character), otherwise the diazonium salt may be partially converted into the corresponding hydroxy compound ... 

Prepare a solution containing about 100 g, of potassium hypochlorite from commercial calcium hypochlorite ( H.T.H. ) as detailed under -Dimethylacrylic Acid, Section 111,142, Note 1, and place it in a 1500 ml. three-necked flask provided with a thermometer, a mechanical stirrer and a reflux condenser. Warm the solution to 55° and add through the condenser 85 g, of p-acetonaphthalene (methyl p-naphthyl ketone) (1). Stir the mixture vigorously and, after the exothermic reaction commences, maintain the temperature at 60-70° by frequent cooling in an ice bath until the temperature no longer tends to rise (ca. 30 minutes). Stir the mixture for a further 30 minutes, and destroy the excess of hypochlorite completely by adding a solution of 25 g. of sodium bisulphite in 100 ml. of water make sure that no hypochlorite remains by testing the solution with acidified potassium iodide solution. Cool the solution, transfer the reaction mixture to a 2-litre beaker and cautiously acidify with 100 ml. of concentrated hydrochloric acid. Filter the crude acid at the pump. 

Method 2. Place a mixture of 126-5 g. of benzyl chloride, 76 g. of thiourea and loO ml. of rectified spirit in a 500 ml. round-bottomed flask fitted with a reflux condenser. Warm on a water bath. A sudden exothermic reaction soon occurs and aU the thiourea passes into solution. Reflux the resulting yellow solution for 30 minutes and then cool in ice. Filter off the white crystals and dry in the air upon filter paper. Concentrate the filtrate to half its original volume and thus obtain a further small crop of crystals. The yield of crude hydrochloric acid as in Method 1 the m.p. is raised to 150°, although on some occasions the form, m.p. 175°, separates. 

Girard s reagent P , C5H5NCH2C0NHNH2 C1. In a 1-htre threenecked flask, equipped as in the previous preparation, place 200 ml. of absolute ethyl alcohol, 63 g. (64 -5 ml.) of pure anhydrous pyridine and 98 - 5 g. (84 5 ml.) of ethyl chloroacetate. Heat the mixture under reflux for 2-3 hours until the formation of the quaternary salt is complete acidify a small test-portion with dilute sulphuric acid it should dissolve completely and no odour of ethyl chloroacetate should be apparent. Cool the mixture in ice and salt. Replace the thermometer by a dropping funnel, and add a solution of 40 g. of 100 per cent, hydrazine hydrate in 60 ml. of absolute ethanol all at once. A vigorous exothermic reaction soon develops and is accompanied by vigorous effervescence. The pro duct separates almost immediately. When cold, filter with suction, wash... 

Prepare a saturated solution of sodium sulphide, preferably from the fused technical sodium polysulphide, and saturate it with sulphur the sulphur content should approximate to that of sodium tetrasulphide. To 50 ml. of the saturated sodium tetrasulphide solution contained in a 500 ml. round-bottomed flask provided with a reflux condenser, add 12 -5 ml. of ethylene dichloride, followed by 1 g. of magnesium oxide to act as catalyst. Heat the mixture until the ethylene dichloride commences to reflux and remove the flame. An exothermic reaction sets in and small particles of Thiokol are formed at the interface between the tetrasulphide solution and the ethylene chloride these float to the surface, agglomerate, and then sink to the bottom of the flask. Decant the hquid, and wash the sohd several times with water. Remove the Thiokol with forceps or tongs and test its rubber-like properties (stretching, etc.). 

A sodium stannite solution was prepared by addition of aqueous sodium hydroxide (2.5 mol, lOOg) to aqueous stannous chloride (0.25 mol, 56g). The initially formed precipitate redissolved to form a clear solution. This solution was gradually added to a solution of 16.3g (0.1 mol) phenyl-2-nitropropene in THF at room temperature. A slightly exothermic reaction ensued, and the reaction mixture was stirred for 30 min, a saturated sodium chloride solution was added, and the solution was extracted with ether and the pooled extracts were evaporated under vacuum to give essentially pure P2P oxime in 80% yield. 

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