AN explosives

The energy released in an explosion in a process plant is either chemical or physical ... 

The hazard of an explosion should in general be minimized by avoiding flammable gas-air mixtures in the process. Again, this can... 

CH2=CHC = CCH = CH2. a colourless liquid which turns yellow on exposure to the air it has a distinct garlic-like odour b.p. 83-5°C. Manufactured by the controlled, low-temperature polymerization of acetylene in the presence of an aqueous solution of copper(I) and ammonium chlorides. It is very dangerous to handle, as it absorbs oxygen from the air to give an explosive peroxide. When heated in an inert atmosphere, it polymerizes to form first a drying oil and finally a hard, brittle insoluble resin. Reacts with chlorine to give a mixture of chlorinated products used as drying oils and plastics. 

Green permanganyI fluoride. MnOjF, is an explosive liquid (KMnO plus HSO3F). 

For olefins, the limits are greater by about 30%. At ambient temperatures, heavy materials have a vapor pressure too low to cause an explosive mixture with air. 

Petroleum solvents are very flammable and can cause an explosion in the presence of air. For this reason, their flash points, directiy related to volatility, are always specified. 

This chapter concludes our discussion of applications of surface chemistry with the possible exception of some of the materials on heterogeneous catalysis in Chapter XVIII. The subjects touched on here are a continuation of Chapter IV on surface films on liquid substrates. There has been an explosion of research in this subject area, and, again, we are limited to providing just an overview of the more fundamental topics. 

CASSCF is a version of MCSCF theory in which all possible configurations involving the active orbitals are included. This leads to a number of simplifications, and good convergence properties in the optimization steps. It does, however, lead to an explosion in the number of configurations being included, and calculations are usually limited to 14 elections in 14 active orbitals. 

The mixture of ammonium nitrate and powdered aluminium is an explosive known as ammonal. 

Manganese is the third most abundant transition metal, and is widely distributed in the earth s crust. The most important ore is pyrolusite, manganese(IV) oxide. Reduction of this ore by heating with aluminium gives an explosive reaction, and the oxide Mn304 must be used to obtain the metal. The latter is purified by distillation in vacuo just above its melting point (1517 K) the pure metal can also he obtained by electrolysis of aqueous manganese(II) sulphate. 

The ethereal extracts are then united, dried with a suitable drying agent and filtered. The filtrate is then cautiously distilled, the ether being first distilled and finally the organic compound if volatile if the compound is solid, the crude residue is purified by recrystallisation. Very great care must be taken on all occasions when ether is distilled because of the risk of fire or of an explosion full experimental details for this operation are given, both on p. 8o (Preparation of Ether) and on p. 164 (Pre-... 

If the contents of the flask are not thoroughly mixed at this stage, an explosion may occur during the subsequent distillation. 

The second danger may arise from the careless treatment of the hydride in a glass vessel with water or acid a significant volume of hydrogen may be evolved, and a fragment of the hydride may ignite and so cause an explosion. These conditions should never arise in the course of careful work. 

Chloroform and carbon tetrachloride must not be heated with metallic sodium as an explosive reaction is likely to take place (see footnote, p. 321). 

The chief danger and main source of error in a combustion is that of moving the Bunsen forward a little too rapidly and so causing much of the substance to burn very rapidly, so that a flash-back occurs. This usually causes an explosion wave to travel back along the tube towards the purification train, some carbon dioxide and water vapour being carried with it. If these reach the packing of the purification train they will, of course, be absorbed there and the results of the estimation will necessarily be low. 

Note. The massive construction of the bomb and its casing makes the risk of an explosion almost negligible. As an additional precaution... 

Pure chloroform has b.p. 61°/760 mm. The solvent, when free from alcohol, should be kept in the dark in order to avoid the photochemical formation of phosgene. It must not be dried with sodium as an explosion may occur. 

Carbon tetrachloride must not be dried with sodium as an explosion may result. Fire extinguishers containing this solvent (e.g., Pyrene ) cannot therefore be applied to a fire originating from sodium. 

When the vigorous reaction commences, the temperature rises to about 105° and remains at this temp>erature for some time. The main quantity of furfural should not be added until the vigorous reaction has started if this precaution is ignored, an explosion may result. 

Fit a 3-litre rovmd-bottomed flask with a long reflux condenser and a dropping funnel (1). Place a mixture of 400 ml. of concentrated nitric acid and 600 ml. of water in the flask and heat nearly to boiling. Allow 100 g. (116 ml.) of cycZopentanone (Section 111,73) to enter the hot acid dropwise, taking care that the first few drops are acted upon by the acid, otherwise an explosion may occur the addition is complete in 1 hour. Much heat is evolved in the reaction so that the flame beneath the flask must be considerably lowered. Omng to the evolution of nitrons fumes, the reaction should be carried out in the fume cupboard or the fumes... 

Htfely stored whilst dry, but this is not recommended in the interest of Safety. Under no circumstances should glass stoppers be employed for potentially explosive substances, since on replacing the stopper some of the material may be ground between the stopper and the neck of the bottle and an explosion may result. 

The mother liquor should not be concentrated as an explosion may result. 

Liquid diazomethane CHjjNj, b.p. —24°, is an explosive compound and explosions may also occur in the gaseous state if the substance is dry and undiluted. The gas may be handled with safety by diluting it with nitrogen. For synthetical work, a dry ethereal solution of the gas is employed and this can be handled with safety due regard must, however, be paid to the poisonous... 

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