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Acetylene

Chemical Formula and Uses of Acetylene

Acetylene or ethyne is a colorless gas with the general molecular formula C2H2 combustion with oxygen to form a luminous smoky flame due to the high carbon materials uses for the oxy-acetylene torch, oxy-acetylene blowpipe for cutting metals or welding equipment and uses for preparation of a large number of compounds like acetaldehyde, ethyl alcohol, and acetic acid. Acetylene is sparingly soluble in water but readily soluble in an acetone solution. The compressed or liquified unsaturated hydrocarbon like acetylene is a highly explosive gas. Therefore, acetylene stored with acetone solution under 10 atm pressure, acetone absorbed some porous materials for settings safety of the cylinder or suppliers tank.

The Lewis structure of the acetylene setup by one triple bond known as the acetylenic chemical bond. The infrared region of the electromagnetic spectrum of ethylene compounds depends on whether they contain acetylenic hydrogen or not. Therefore, in RC≡CH, one region having frequency 3310-3300 cm-1 due to the ≡C-H stretch and another region having frequency 2140-2100 cm-1 due to the C≡C stretch.

Preparation Process

Acetylene is an important member of the alkyne series prepared industrially by the action of water on calcium carbide. Other methods for the preparation of the alkynes in learning chemistry are

Acetylene gas preparation, properties and uses in oxy-acetylene cylinder torch or welding setup

  1. The creaking of methane ethane mixture.
  2. Heating a mixture of ethane or propane with the stream about 1000-1300°C temperature. Natural gas also uses for the starring materials for the preparation of acetylene.
  3. Electrolysis of the concentrated sodium or potassium salt of the maleic or fumaric acid solution by Kolbe method.

Ethylene also prepared by the action of ethanolic potassium hydroxide on ethyl bromide solution. The reactions process in two steps. Under suitable conditions, the intermediate vinyl bromide also is isolated. Sodamide in liquid ammonia used instead of ethanolic potassium hydroxide in the acetylene preparation process. Since there is less tendency to form by-product.

BrCH2CH2Br + KOH → CH2=CHBr + KBr + H2O
CH2=CHBr + KOH → CH≡CH + KBr + H2O

Chemical Properties of Acetylene

Owing to the presence of a triple bond, acetylene is more unsaturated hydrocarbon than ethylene and forms addition products with two or four univalent atoms or groups. The triple bond consists of one sigma and two pi-bonds to forms a linear molecule. When two univalent atoms add to the triple bond the diagonal arrangement changes into the trigonal or tetrahedral arrangement. Therefore under suitable conditions ethylene uses to isolate the intermediate alkene or olefins like ethylene, propylene, butylene with trigonal structural formula.

Therefore, CH≡CH adds on hydrogen atom in the presence of the chemical catalyst. The reaction process in the two stages by the preparation of alkenes and alkanes. But we use a suitable catalyst like Lindlar’s catalyst for conversion alkyne to the alkene. Lindlar’s catalyst consists of Pd-CaCO3 partially poisoned with lead acetate. But the better catalyst for this conversion process is Pd- BaSO4 partially poisoned with quinoline.

Uses of Acetylene Compounds

Acetylene not only uses in an oxy-acetylene torch or welding material setup it also uses for the synthesis of many chemical compounds like organic alcohol, ether or acid, and chemical industry for the preparation of synthetic rubber and plastic bottles.

  • Acetylene added on hydrogen cyanide in presence of cuprous chloride catalyst to form vinyl cyanides uses for the manufacture of Buna synthetic rubber. This is the copolymer of vinyl cyanide and butadiene. Vinyl cyanide also prepared by passing the mixture of ammonia, steam, and air over the catalyst like oxide of the chemical elements molybdenum or cobalt.
  • Vinyl acetate compounds in chemistry manufactured by passing the mixture of acetylene and acetic acid vapor over zinc acetate on charcoal at about 170°C used in the plastic industry for making plastic bottle, toys, etc.