Acetylene, commonly known as calcium carbide gas, is the product of the interaction between calcium carbide (CaC2) and water. As early as 1836, the famous British chemist Humphrey? Edmund, cousin of humphry davy (1778- 1829), professor of chemistry at the Royal College Cork? Edmund David (1785- 1857) tried to obtain metallic potassium by heating charcoal with potassium carbonate. The result is a black object, which produces gas when it meets water and explodes when it burns. He determined the composition of this gas and determined its molecular formula as C2H, which is called "new hydrogen carbide". Now it is clear that this black object is potassium carbide, and the gas produced when it meets water is acetylene. Because the relative atomic mass of carbon at that time was set at 6 instead of 12 today, its molecular formula should be C2H2. The name "new hydrogen carbide" comes from his compatriot, chemist and physicist Faraday (179 1- 1867) before obtaining this gas. A substance separated from the compressed condensate of whale oil decomposition gas used by Europeans at that time was determined by Faraday analysis. Its molecular formula is C2H, which is called "hydrogen carbide". Actually, it's benzene, and its molecular formula is C6H6.
26 years later 1862, German chemist Friedrich W? Hler, 1800- 1882) Calcium-zinc alloy is strongly heated with charcoal to obtain calcium carbide, which reacts with water to obtain acetylene;
In the same year, French chemist Berthelot made acetylene by various methods. He let the steam of ethylene, ether, methanol and ethanol pass through a red-hot pipe; Passing the mixture of hydrogen and cyanogen gas through an electric spark; Hydrogen is also directly synthesized into acetylene through the combustion arc between two carbon electrodes (Figure 12- 1). He determined whether the chemical composition of acetylene is C4H2 or whether the relative atomic mass of carbon is 6, and named it acetylene.
Another 30 years later, French chemist Mu Wasang (1892) invented the electric arc furnace, which made coke and quicklime act in the electric arc furnace to generate calcium carbide.
Calcium carbide generates acetylene when it meets water.
However, the acetylene made by these chemists is only an experiment in the chemistry laboratory. 1892, Canadian electrical engineer Thomas Leopold Willson (1860- 19 15) put acetylene into industrial scale production and sought its application.
1882, Wilson moved to the United States, operated Wilson Aluminum Company in Spray, North Carolina, and built the largest electric arc furnace in the world at that time. He tried to make aluminum from coal tar and bauxite, a kind of ore containing alumina, but failed. So he used coal and quicklime to act in the electric furnace to obtain metallic calcium, and then reduced bauxite with metallic calcium to obtain aluminum. Results1May 2, 892, a black brittle substance was obtained, but no calcium was obtained. He dumped these wastes into the water, producing a lot of gas, emitting bright flames and a lot of black smoke. Wilson got the same result in several experiments. He once went to college to study chemistry and realized that this gas is not hydrogen, but a gas containing hydrocarbons, otherwise it would not produce black smoke. He sent the sample to Venable, a professor of chemistry at the University of North Carolina, for analysis and identification, and determined that the black fragile substance was calcium carbide and the gas produced was acetylene. So he decided to put into industrial production, filed a patent application on August 9, 1992, and sent the sample and a letter to Baron Kelvin on June 3, 1938 (1824- 1907). Baron Kelvin is a British physicist, formerly known as William Thomson, who was awarded the title of Baron in 1892. Wilson sent him samples and letters in order to leave proof.
1894, Wilson sold the manufacturing patents of calcium carbide and acetylene to the American electric company. 1895 returned to Canada and was funded by the financial banker James Turner morehead. 1896, Wilson established a carbide factory in Moriton, Ontario, Canada, and then successively established factories in Britain, Germany and the United States.
Bernard Schell. Opportunity favors those who are prepared. Part X, Acetylene. Chemistry,1967,40 (3).
At first, people didn't know how to use acetylene. Wilson distributed samples and used knowledge books. The burning acetylene will soon become the fuel for miner's lamps, desk lamps, portable lamps, signal lamps, bicycle lamps and street lamps.
1895, Le Chatterley, a French metallurgical engineer and chemist, submitted a report to the French Academy of Sciences, pointing out that the combustion of acetylene with equal volume of oxygen will produce high temperature. However, the actual results show that acetylene in compressed state is dangerous and will explode. 1897, French chemist and engineer George Claude (1870- 1960) found that acetylene can be easily absorbed and dissolved by acetone and can be safely used in steel cylinders. 190 1 Edmund France? Edmund Fauci and Devi? The two brothers Davis Fouché completed the design of the torch, so oxyacetylene flame is widely used in metal cutting and welding (Figure 12-2).
Acetic acid further reacts with acetylene to produce vinyl acetate, which is the raw material for making rayon.
Acetylene reacts with hydrogen chloride to produce vinyl chloride (CH2=CHCl), which is the raw material for making various plastic sandals and plastic films. Acetylene is also a raw material for making artificial rubber.
In order to meet the demand, acetylene has been produced in large quantities through methane (CH4) cracking.
The cost of producing acetylene by methane cracking is lower than that by adding water to calcium carbide. This was carried out at a high temperature of 1500~ 1600℃. First, one methane molecule breaks the carbon-hydrogen bond at high temperature, and it will combine with another methane molecule that also breaks the carbon-hydrogen bond to generate ethane (C2H6):
CH3+CH3─→ch3ch 3 Under the high temperature above 1000℃, the generated ethane will be cracked again immediately. One is that the carbon-carbon bond breaks back to its original state, and the other is that each carbon atom breaks a carbon-hydrogen bond to become ethylene:
Ethylene will also crack at a high temperature above 1000℃, but unlike ethane, because carbon atoms are connected by double bonds, which are much stronger than single bonds, the possibility of carbon-hydrogen bond breakage of ethylene is greater than that of ethane, so ethylene is converted into acetylene;
The carbon atoms of acetylene are connected by three bonds, which is more stable than ethane and ethylene and not easy to crack, but it will also crack into carbon black and hydrogen at the high temperature of 1500~ 1600℃ for a long time.
Therefore, methane is cracked at 1500~ 1600℃ and changes along the path of ethane, ethylene, acetylene and carbon black. If the temperature suddenly drops to a low level after it becomes acetylene, so that the cracking will not continue, then the acetylene product will be obtained. Therefore, the preparation of acetylene from methane requires two conditions. One is to treat methane at a high temperature of 65,438+0,500 ~ 65,438+0,600℃, and the other is to treat methane in a very short time. Then, the temperature of the cracking gas is reduced to below the cracking temperature by quenching. There are various modes of production, and many factories have been established in various countries.