How to use Acetylene in a sentence
For example, ethylene, C2H4 j is formed with absorption of 16200 cal., acetylene, C 2 H 2, with absorption of 59100 cal., and liquid benzene, C 6 H 6, with absorption of 9100 cal.
It will be noticed that compounds containing two double linkages will have the same general formula as the acetylene series; such compounds are known as the " diolefines."
Passed through a red-hot tube, benzene vapour yields hydrogen, diphenyl, diphenylbenzenes and acetylene; the formation of the last compound is an instance of a reversible reaction, since Berthelot found that acetylene passed through a red-hot tube gave some benzene.
It resembles acetylene in yielding metallic derivatives with ammoniacal copper and silver solutions.
They found that if liquid acetylene in a steel bottle be heated at one point by a platinum wire raised to a red heat, the whole mass decomposes and gives rise to such tremendous pressures that no cylinder would be able to withstand them.Advertisement
Continuing these experiments, they found that in acetylene gas under ordinary pressures the decomposition brought about in one portion of the gas, either by heat or the firing in it of a small detonator, did not spread far beyond the point at which the decomposition started, while if the acetylene was compressed to a pressure of more than 30 lb on the square inch, the decomposition travelled throughout the mass and became in reality detonation.
These results showed clearly that liquefied acetylene was far too dangerous for general introduction for domestic purposes, since, although the occasions would be rare in which the requisite temperature to bring about detonation would be reached, still, if this point were attained, the results would be of a most disastrous character.
The fact that several accidents had already happened accentuated the risk, and in Great Britain the storage and use of liquefied acetylene are prohibited.
Acetylene is readily soluble in water, which at normal temperature and pressure takes up a little more than its own volume of the gas, and yields a solution giving a purple-red precipitate with ammoniacal cuprous chloride and a white precipitate with silver nitrate, these precipitates consisting of acetylides of the metals.
The solubility of the gas in various liquids, as given by different observers, is zoo Volumes of Brine Water Alcohol Paraffin Carbon disulphide Fusel oil Benzene Chloroform Acetic acid Acetone It will be seen from this table that where it is desired to collect and keep acetylene over a liquid, brine, i.e.Advertisement
At first it seemed as if this discovery would do away with all the troubles connected with the storage of acetylene under pressure, but it was soon found that there were serious difficulties still to be overcome.
The chief trouble was that acetone expands a small percentage of its own volume while it is absorbing acetylene; therefore it is impossible to fill a cylinder with acetone and then force in acetylene, and still more impracticable only partly to fill the cylinder with acetone, as in that case the space above the liquid would be filled with acetylene under high pressure, and would have all the disadvantages of a cylinder containing compressed acetylene only.
This difficulty was overcome by first filling the cylinder with porous briquettes and then soaking them with a fixed percentage of acetone, so that after allowing for the space taken up by the bricks the quantity of acetone soaked into the brick will absorb ten times the normal volume of the cylinder in acetylene for every atmosphere of pressure to which the gas is subjected, whilst all danger of explosion is eliminated.
Paraffins are found in all crude oils, and olefines in varying proportions in the majority, while acetylene has been found in Baku oil; members of the benzene group and its derivatives, notably benzene and toluene, occur in all petroleums. Naphthenes are the chief components of some oils, as already indicated, and occur in varying quantities in many others.
B aeyer has suggested that his hypothesis may also be applied to explain the instability of acetylene and its derivatives, and the still greater instability of the polyacetylene compounds.Advertisement
Crismer, and others, all conclusively show that acetylene is much less toxic than carbon monoxide, and indeed than coal gas.
Berthelot was the first to suggest, in 1866, after conducting a series of experiments, that mineral oil was produced by purely chemical action, similar to that employed in the manufacture of acetylene.
Stohmann of Leipzig; and the new data and the conclusions to be drawn from them formed the subject of much discussion, Briihl endeavouring to show how they supported Kekule's formula, while Thomsen maintained that they demanded the benzene union to have a different heat of combustion from the acetylene union.
It also results on condensing acetylene, and on reducing phenylacetylene by zinc dust and acetic acid.
It resembles calcium carbide, decomposing rapidly with water, giving acetylene.Advertisement
This fact having been fully demonstrated, acetylene dissolved in this way was exempted from the Explosives Act, and consequently upon this exemption a large business has grown up in the preparation and use of dissolved acetylene for lighting motor omnibuses, motor cars, railway carriages, lighthouses, buoys, yachts, &c., for which it is particularly adapted.
When acetylene was first introduced on a commercial scale grave fears were entertained as to its safety, it being represented that it had the power of combining with certain metals, more especially copper and silver, to form acetylides of a highly explosive character, and that even with coal gas, which contains less than i %, such copper compounds had been known to be formed in cases where the gas-distributing mains were composed of copper, and that accidents had happened from this cause.
It was therefore predicted that the introduction of acetylene on a large scale would be followed by numerous accidents unless copper and its alloys were rigidly excluded from contact with the gas.
Acetylene has the property of inflaming spontaneously when brought in contact with chlorine.
If chlorine be bubbled up into a jar of acetylene standing over water, a violent explosion, attended with a flash of intense light and the deposition of carbon, at once takes place.Advertisement
Acetylene is readily decomposed by heat, polymerizing under its influence to form an enormous number of organic of compounds; indeed the gas, which can itself be directly prepared from its constituents, carbon and hydrogen, under the influence of the electric arc, can be made the startingpoint for the construction of an enormous number of different organic compounds of a complex character.
Picric acid can also be obtained from it by first treating acetylene with sulphuric acid, converting the product into phenol by solution in potash and then treating the phenol with fuming nitric acid.
For its complete combustion a volume of acetylene needs approximately twelve volumes of air, forming as products of combustion carbon dioxide and water vapour.
This is well shown by taking a cylinder one-half full of acetylene and one-half of air; on applying a light to the mixture a lurid flame runs down the cylinder and a cloud of soot is thrown up, the cylinder also being thickly coated with it, and often containing a ball of carbon.
It is probable that when a flame is smoking badly, distinct traces of carbon monoxide are being produced, but when an acetylene flame burns properly the products are as harmless as those of coal gas, and, light for light, less in amount.
This on being washed and decomposed with hydrochloric acid yielded a stream of acetylene gas.
This second method of production has the great drawback that, unless proper precautions are taken to purify the gas obtained from the copper acetylide, it is always contaminated with certain chlorine derivatives of acetylene.
Edmund Davy first made acetylene in 1836 from a compound produced during the manufacture of potassium from potassium tartrate and charcoal, which under certain conditions yielded a black compound decomposed by water with considerable violence and the evolution of acetylene.
Wohler first made calcium carbide, and found that water decomposed it into lime and acetylene.
It can be kept unaltered in dry air, but the smallest trace of moisture in the atmosphere leads to the evolution of minute quantities of acetylene and gives it a distinctive odour.
Acted upon by water it is at once decomposed, yielding acetylene and calcium hydrate.
Pure crystalline calcium carbide yields 5.8 cubic feet of acetylene per pound at ordinary temperatures, but the carbide as sold commercially, being a mixture of the pure crystalline material with the crust which in the electric furnace surrounds the ingot, yields at the best 5 cubic feet of gas per pound under proper conditions of generation.
The purity of the carbide entirely depends on the purity of the material used in its manufacture, and before this fact had been fully grasped by manufacturers, and only the purest material obtainable employed, it contained notable quantities of compounds which during its decomposition by water yielded a somewhat high pro portion of impurities in the acetylene generated from it.
Although at the present time a marvellous improvement has taken place all round in the quality of the carbide produced, the acetylene nearly always contains minute traces of hydrogen, ammonia, sulphuretted hydrogen, phosphuretted hydrogen, silicon hydride, nitrogen and oxygen, and sometimes minute traces of carbon monoxide and dioxide.
The ammonia found in the acetylene is probably partly due to the presence of magnesium nitride in the carbide.
Sulphuretted hydrogen, which is invariably present in commercial acetylene, is formed by the decomposition of aluminium sulphide.
Phosphuretted hydrogen, one of the most important impurities, which has been blamed for the haze formed by the combustion of acetylene under certain conditions, is produced by the action of water upon traces of calcium phosphide found in carbide.
In the generation of acetylene from calcium carbide and water, all that has to be done is to bring these two compounds into contact, when they mutually react upon each other with the formation of lime and acetylene, while, if there be sufficient water present, the lime combines with it to form calcium hydrate.
It is found that the ingot of calcium carbide formed in the furnace, although itself consisting of pure crystalline calcium carbide, is nearly always surrounded by a crust which contains a certain proportion of imperfectly converted constituents, and therefore gives a lower yield of acetylene than the carbide itself.
It is clear that acetylene, if it is to be used on a large scale as a domestic illuminant, must undergo such processes of purification as will render it harmless and innocuous to health and property, and the sooner it is recognized as absolutely essential to purify acetylene before consuming it the sooner will the gas acquire the popularity it deserves.
In experiments with these various bodies it is found that they are all of them effective in also ridding the acetylene of the ammonia and sulphuretted hydrogen, provided only that the surface area presented to the gas is sufficiently large.
Where the production of acetylene is going on on a small scale this method of purification is undoubtedly the most convenient one, as the acid present absorbs the ammonia, and the copper salt converts the phosphuretted and sulphuretted hydrogen into phosphates and sulphides.
Dr P. Wolff has found that when this is used on the large scale there is a risk of the ammonia present in the acetylene forming traces of chloride of nitrogen in the purifying-boxes, and as this is a compound which detonates with considerable local force, it occasionally gives rise to explosions in the purifying apparatus.
When acetylene is burnt from a 000 union jet burner, at all ordinary pressures a smoky flame is obtained, but on the pressure being increased to 4 inches a magnificent flame results, free from smoke, and developing an illuminating value of 240 candles per 5 cubic feet of gas consumed.
When acetylene was first introduced as a commercial illuminant in England, very small union jet nipples were utilized for its consumption, but after burning for a short time these nipples began to carbonize, the flame being distorted, and then smoking occurred with the formation of a heavy deposit of soot.
While these troubles were being experienced in England, attempts had been made in America to use acetylene diluted with a certain proportion of air which permitted it to be burnt in ordinary flat flame nipples; but the danger of such admixture being recognized, nipples of the same class as those used in England were employed, and the same troubles ensued.
Ragot and others made burners in which two jets of acetylene, coming from two tubes placed some little distance apart, impinged and splayed each other out into a butterfly flame.
Billwiller introduced the idea of sucking air into the flame at or just below the burner tip, and at this juncture the Naphey or Dolan burner was introduced in America, the principle employed being to use two small and widely separated jets instead of the two openings of the union jet burner, and to make each a minute bunsen, the acetylene dragging in from the base of the nipple enough air to surround and protect it while burning from contact with the steatite.
When acetylene was first introduced on a commercial scale attempts were made to utilize its great heat of combustion by using it in conjunction with oxygen in the oxy hydrogen blowpipe.
It was found, however, that when Oxyacetylene using acetylene under low pressures, the burner tip blowpipe.
The introduction of acetylene dissolved under pressure in acetone contained in cylinders filled with porous material drew attention again to this use of the gas, and by using a special construction of blowpipe an oxy-acetylene flame is produced, which is far hotter than the oxy-hydrogen flame, and at the same time is so reducing in its character that it can be used for the direct autogenous welding of steel and many minor metallurgical processes.
The amount of methyl alcohol present in wood spirit is determined by converting it into methyl iodide by acting with phosphorus iodide; and the acetone by converting it into iodoform by boiling with an alkaline solution of iodine in potassium iodide; ethyl alcohol is detected by giving acetylene on heating with concentrated sulphuric acid, methyl alcohol, !under the same circumstances, giving methyl ether.
There are wood-pulp factories (one worked by an English company employing over 1000 hands), factories for calcium carbide (used for manufacturing acetylene gas), paper and aluminium; and spinning and weaving mills.
A faint smell of acetylene may be perceived during the oxidation in moist air; this is probably due to traces of calcium carbide.
Water decomposes it to give hydrogen free from ammonia and acetylene, i gram yielding about loo ccs.
It is now manufactured by heating lime and carbon in the electric furnace (see Acetylene).
It is also noted for its bleach and dye works, its engine works, foundries, paper factories, and production of silk goods, watches, jewelry, mathematical instruments, leather, chemicals, &c. Augsburg is also the centre of the acetylene gas industry of Germany.
Its solution in hydrochloric acid readily absorbs carbon monoxide and acetylene; hence it finds application in gas analysis.
This solution absorbs acetylene with the precipitation of red cuprous acetylide, Cu 2 C 2, a very explosive compound.
Barium carbide, BaC2, is prepared by a method similar to that in use for the preparation of calcium carbide (see Acetylene).
Kdnigs, Ber., 1879, 12, p. 2341) by passing a mixture of acetylene and hydrocyanic acid through a red-hot tube (W.
It also acts in an opposite manner in certain cases, adding the elements of water to compounds; thus, nitriles are converted into acid-amides, and various acetylene derivatives may be caused to yield ketonic derivatives.
Ethane, when heated to this degree, splits up into ethylene and hydrogen, whilst ethylene decomposes to methane and acetylene, and the acetylene at once polymerizes to benzene, styrolene, retene, &c. A portion also condenses, and at the same time loses some hydrogen, becoming naphthalene; and the compounds so formed by interactions amongst themselves build up the remainder of the hydrocarbons present in the coal tar, whilst the organic substances containing oxygen in the coal break down, and cause the formation of the phenols in the tar.
There is very little doubt that the general course of the decompositions follows these iines; but any such simple explanation of the actions taking place is rendered impossible by the fact that, instead of the breaking-down of the hydrocarbons being completed in the coal, and only secondary reactions taking place in the retort, in practice the hydrocarbons to a great extent leave the coal as the vapours of condensible hydrocarbons, and the breaking down of these to such simple gaseous compounds as ethylene is proceeding in the retort at the same time as the breaking up of the ethylene already formed into acetylene and methane, and the polymerization of the former into higher compounds.
The valve on top of a cylinder containing the highly volatile substance acetylene had ignited on the sixth floor.
And a dangerous flashback can occur when workers are using acetylene for welding, cutting and similar work.
Thus the heat generated by the combustion of acetylene, C 2 H 2, is 316000 cal., whereas the heat of combustion of the carbon and hydrogen composing it is only 256900 cal., the difference being equal to the negative heat of formation of the acetylene.
Acetylene is one of those bodies the formation of which is attended with the disappearance of heat, and it is for this reason termed an "endothermic" compound, in contradis thermic tinction to those bodies which evolve heat in their nature of formation, and which are called "exothermic."
Such endothermic bodies are nearly always found to show considerable violence in their decomposition, as the heat of formation stored up within them is then liberated as sensible heat, and it is undoubtedly this property of acetylene gas which leads to its easy detonation by either heat or a shock from an explosion of fulminating mercury when in contact with it under pressure.
In attempting to classify acetylene generators some authorities have divided them into as many as six different classes, but this is hardly necessary, as they may be divided into two main classes - first, those in which water is brought in contact with the carbide, the carbide being in excess during the first portion of the operation; and, second, those in which the carbide is thrown into water, the amount of water present being always in excess.
You can jump between pickup and police car and there is a giant acetylene flashlight to set your opponents on fire !
Amongst endothermic compounds may be noted hydriodic acid, HI, acetylene, C 2 H 2, nitrous oxide, N 2 O, nitric oxide, NO, azoimide, N 3 H, nitrogen trichloride, NC1 3.
Vieille made a series of valuable researches upon the explosion of acetylene under various conditions.
The methods which can be and have been employed from time to time for the formation of acetylene in small quantities are exceedingly numerous.