Gas Description
Acetylene, with the molecular formula C2H2, commonly known as wind coal and carbide gas, is the smallest member of the alkyne compound series and is mainly used for industrial purposes, especially in the welding of metals. Acetylene is a colorless and highly flammable gas at room temperature. Pure acetylene is odorless, but industrial acetylene has a garlic like odor due to impurities such as hydrogen sulfide and phosphine.
Main uses
Acetylene can be used for lighting, welding, and cutting metals (oxyacetylene flames), and is also a basic raw material for manufacturing acetaldehyde, acetic acid, benzene, synthetic rubber, synthetic fibers, and so on.
Acetylene combustion can generate high temperatures, and the temperature of the oxyacetylene flame can reach around 3200 ℃, which is used for cutting and welding metals. Providing an appropriate amount of air can completely burn and emit bright white light. It can be used as a lighting source in areas where electric lights are not widely used or there is no electricity. Acetylene has active chemical properties and can undergo addition reactions with many reagents. Before the 1960s, acetylene was the most important raw material for organic synthesis and remains one of the important raw materials today. If it is added with hydrogen chloride, hydrogen cyanide, or acetic acid, it can all generate raw materials for producing polymers.
Acetylene can undergo different polymerization reactions under different conditions, producing either vinyl acetylene or divinyl acetylene. The former can be added with hydrogen chloride to obtain the raw material 2-chloro-1,3-butadiene for the production of chloroprene rubber. Acetylene can undergo cyclic triple polymerization to form benzene at high temperatures of 400-500 ℃; Using nickel cyanide Ni (CN) 2 as a catalyst, cyclohexene can be generated at 50 ℃ and 1.2-2 MPa.
Acetylene decomposes into carbon and hydrogen at high temperatures, from which acetylene carbon black can be prepared. Under certain conditions, acetylene polymerization generates aromatic hydrocarbons such as benzene, toluene, xylene, naphthalene, anthracene, styrene, indene, etc. A series of highly valuable products can be generated through substitution and addition reactions. For example, acetylene dimerization generates vinyl acetylene, which then undergoes an addition reaction with hydrogen chloride to obtain chloroprene; Direct hydration of acetylene to produce acetaldehyde; Acetylene undergoes an addition reaction with hydrogen chloride to produce vinyl chloride; Acetylene reacts with acetic acid to produce ethylene acetate; Acetylene reacts with hydrogen cyanide to produce acrylonitrile; Acetylene reacts with ammonia to produce methylpyridine and 2-methyl-5-ethylpyridine; Acetylene reacts with toluene to produce xylenylethylene, which is further cracked by a catalyst to produce three isomers of methylstyrene: acetylene condenses with one molecule of formaldehyde to propargyl alcohol, and with two molecules of formaldehyde to butynediol; Acetylene and acetone undergo an addition reaction to produce methylpropanol, which in turn reacts to produce isoprene; Acetylene reacts with carbon monoxide and other compounds (such as water, alcohols, thiols) to produce acrylic acid and its derivatives.
