Acetylene technical - from 25 000 - 30 000 tenges
Acetylene (on IYuPAK — etin) — C2H2 unsaturated hydrocarbon. Has threefold communication between atoms of carbon, belongs to a class of alkynes.
Physical properties [to govern | to edit the viki-text]
Under normal conditions — colourless gas, is lighter than air. The pure 100% acetylene do not possess a smell, however technical acetylene contains impurity which give it a pungent smell [2]. It is slightly soluble in water, it is well dissolved in acetone. Boiling temperature −83,6 °C [3]. A threefold point −80,55 °C with a pressure of 961,5 mm Hg, a critical point of 35,18 °C with a pressure of 61,1 atm [4].
Acetylene demands big care at the address. Can blow up from blow, when heating to 500 °C or at compression to 1,4 atm [the source is not specified 256 days] at the room temperature. The acetylene stream which is let out on open air can light up from the slightest spark, including from an electrostatic discharge from a hand finger. For storage of acetylene the special cylinders filled with the porous material impregnated with acetone [5] are used.
C2H2 is found on Uranium and the Neptune.
Chemical properties [to govern | to edit the viki-text]
Oxyacetylene flame (temperature of "kernel" of 2621 °C)
Accession reactions are characteristic of acetylene (etin):
HC≡CH + Cl2-> CLCH = CHCL
Acetylene with water, in the presence of salts of mercury and other catalysts, forms acetic aldehyde (Kucherov's reaction). Owing to existence of threefold communication, the molecule of a vysokoenergetichn also has the big specific heat of combustion — 14000 kcal/m ³ (50,4 MDzh/Kg). At combustion in oxygen temperature of a flame reaches 3150 °C. Acetylene can polymerize in benzene and other organic compounds (polyacetylene, vinylacetylene). Graphite and temperature in 400 °C is necessary for polymerization in benzene.
Besides, atoms of hydrogen of acetylene are rather easily chipped off in the form of protons, that is he shows acid properties. So acetylene forces out methane from radio solution of a metilmagniybromid (the solution containing acetyleneides ions is formed), forms insoluble explosive rainfall with salts of silver and monovalent copper.
Acetylene decolours bromic water and solution of permanganate of potassium.
Reacts with ammoniac solutions of Cu (I) and Ag (I) salts with formation of slightly soluble, explosive atsetilenid - this reaction is used for high-quality definition of acetylene and its difference from alkenes (which decolour bromic water and solution of permanganate of potassium too).
History [to govern | to edit the viki-text]
E. Davy is open in 1836, M. Bertlo is synthesized from coal and hydrogen (the arc category between two coal electrodes in the atmosphere of hydrogen) (1862).
Way of production [to govern | to edit the viki-text]
The laboratory receives acetylene effect of water on calcium carbide see video of this process (F. Vyoler, 1862),
and also at dehydrogenation of two molecules of methane at a temperature over 1400 °C:
[To correct application | to edit the viki-text]
Acetylene lamp
Acetylene is used:
for welding and cutting of metals,
as a source of very bright, this world in independent lamps where it turns out reaction of carbide of calcium and water (see a carbide lamp),
in production of explosives (see acetyleneides),
for receiving acetic acid, ethyl alcohol, solvents, plastics, rubber, aromatic hydrocarbons.
for receiving technical carbon
in a nuclear and absorbing spektrofotometriya at ardent atomization
in rocket engines (together with ammonia) [6]
Safety [to govern | to edit the viki-text]
As acetylene is insoluble in water, and its mixes with oxygen can explode in very wide range of concentration, he cannot be collected in gasometers.
Acetylene explodes at a temperature about 500 °C or pressure over 0,2 MPas; KPV of 2,3-80,7%, temperature of spontaneous ignition is 335 °C. Potential of explosion decreases at acetylene dilution by other gases, for example nitrogen, methane or propane.
At long contact of acetylene with copper and silver acetyleneides of copper and silver which blow up at blow or temperature increase are formed. Therefore at storage of acetylene the materials containing copper are not used (for example, gates of cylinders).
Acetylene possesses weak toxic action. For acetylene normirovan Pdkm.R. = Maximum concentration limit of village of the village = 1,5 mg/m3 according to hygienic standards of GN 2.1.6.1338-03 "The Maximum Permissible Concentration (MPC) of the polluting substances in atmospheric air of the inhabited places".
Pdkr.z. (a working zone) it is not established (in accordance with GOST 5457-75 and GN 2.2.5.1314-03) as concentration limits of distribution of a flame in mix with air are made by 2,5-100%.
Store and transport it in filled with inert porous weight (for example, charcoal) steel cylinders of white color (with a red inscription "A") in the form of solution in acetone under pressure of 1,5-2,5 MPas.