Calcium carbide

Last updated
Calcium carbide
Calcium carbide formula.png
Karbid vapenaty.JPG
Names
Preferred IUPAC name
Calcium acetylide
Systematic IUPAC name
Calcium ethynediide
Other names
Calcium percarbide
Calcium carbide
Calcium dicarbide
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.000.772 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 200-848-3
PubChem CID
UNII
  • InChI=1S/C2.Ca/c1-2;/q-2;+2 Yes check.svgY
    Key: UIXRSLJINYRGFQ-UHFFFAOYSA-N Yes check.svgY
  • InChI=1/C2.Ca/c1-2;/q-2;+2
    Key: UIXRSLJINYRGFQ-UHFFFAOYAI
  • [Ca+2].[C-]#[C-]
Properties
CaC2
Molar mass 64.099 g/mol
AppearanceWhite powder or colorless crystals, grey/brown/black crystals if impure
Density 2.22 g/cm3
Melting point 2,160 °C (3,920 °F; 2,430 K)
Boiling point 2,300 °C (4,170 °F; 2,570 K)
Reacts to produce Acetylene
Structure [1]
Tetragonal (I phase)
Monoclinic (II phase)
Monoclinic (III phase)
I4/mmm (I phase)
C2/c (II phase)
C2/m (III phase)
6
Thermochemistry
Std molar
entropy (S⦵298)
70 J·mol−1·K−1
−63 kJ·mol−1
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
Reacts with water to release acetylene gas [2]
GHS labelling:
GHS-pictogram-flamme.svg GHS-pictogram-acid.svg
Danger
H260
NFPA 704 (fire diamond)
NFPA 704.svgHealth 1: Exposure would cause irritation but only minor residual injury. E.g. turpentineFlammability 4: Will rapidly or completely vaporize at normal atmospheric pressure and temperature, or is readily dispersed in air and will burn readily. Flash point below 23 °C (73 °F). E.g. propaneInstability 2: Undergoes violent chemical change at elevated temperatures and pressures, reacts violently with water, or may form explosive mixtures with water. E.g. white phosphorusSpecial hazard W: Reacts with water in an unusual or dangerous manner. E.g. sodium, sulfuric acid
1
4
2
W
305 °C (581 °F; 578 K) (acetylene)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Yes check.svgY  verify  (what is  Yes check.svgYX mark.svgN ?)

Calcium carbide, also known as calcium acetylide, is a chemical compound with the chemical formula of Ca C2. Its main use industrially is in the production of acetylene and calcium cyanamide. [3]

Contents

The pure material is colorless, while pieces of technical-grade calcium carbide are grey or brown and consist of about 80–85% of CaC2 (the rest is CaO (calcium oxide), Ca3P2 (calcium phosphide), CaS (calcium sulfide), Ca3N2 (calcium nitride), SiC (silicon carbide), C (carbon), etc.). In the presence of trace moisture, technical-grade calcium carbide emits an unpleasant odor reminiscent of garlic. [4]

Applications of calcium carbide include manufacture of acetylene gas, generation of acetylene in carbide lamps, manufacture of chemicals for fertilizer, and steelmaking.

Production

Calcium carbide is produced industrially in an electric arc furnace from a mixture of lime and coke at approximately 2,200 °C (3,990 °F). [5] This is an endothermic reaction requiring 110 kilocalories (460 kJ) per mole [6] and high temperatures to drive off the carbon monoxide. This method has not changed since its invention in 1892:

CaO + 3 C → CaC2 + CO

The high temperature required for this reaction is not practically achievable by traditional combustion, so the reaction is performed in an electric arc furnace with graphite electrodes. The carbide product produced generally contains around 80% calcium carbide by weight. The carbide is crushed to produce small lumps that can range from a few mm up to 50 mm. The impurities are concentrated in the finer fractions. The CaC2 content of the product is assayed by measuring the amount of acetylene produced on hydrolysis. As an example, the British and German standards for the content of the coarser fractions are 295 L/kg and 300 L/kg respectively (at 101 kPa pressure and 20 °C (68 °F) temperature). Impurities present in the carbide include calcium phosphide, which produces phosphine when hydrolysed. [7]

This reaction was an important part of the Industrial Revolution in chemistry, and was made possible in the United States as a result of massive amounts of inexpensive hydroelectric power produced at Niagara Falls before the turn of the 20th century. [8] The electric arc furnace method was discovered in 1892 by T. L. Willson, and independently in the same year by H. Moissan. [9] [10] [11] In Jajce, Bosnia and Herzegovina, the Austrian industrialist Josef Kranz and his "Bosnische-Elektrizitäts AG" company, whose successor later became "Elektro-Bosna", opened the largest chemical factory for the production of calcium carbide at the time in Europe in 1899. A hydroelectric power station on the Pliva river with an installed capacity of 8 MW was constructed to supply electricity for the factory, the first power station of its kind in Southeast Europe, and became operational on 24 March 1899. [12]

Crystal structure

Pure calcium carbide is a colourless solid. The common crystalline form at room temperature is a distorted rock-salt structure with the C22− units lying parallel. [13] There are three different polymorphs which appear at room temperature: the tetragonal structure and two different monoclinic structures. [1]

Applications

Production of acetylene

The reaction of calcium carbide with water, producing acetylene and calcium hydroxide, [5] was discovered by Friedrich Wöhler in 1862.

CaC2(s) + 2H2O(l) → C2H2 (g) + Ca(OH)2 (aq)

This reaction was the basis of the industrial manufacture of acetylene, and is the major industrial use of calcium carbide.

Today acetylene is mainly manufactured by the partial combustion of methane or appears as a side product in the ethylene stream from cracking of hydrocarbons. Approximately 400,000 tonnes are produced this way annually (see acetylene preparation).

In China, acetylene derived from calcium carbide remains a raw material for the chemical industry, in particular for the production of polyvinyl chloride. Locally produced acetylene is more economical than using imported oil. [14] Production of calcium carbide in China has been increasing. In 2005 output was 8.94 million tons, with the capacity to produce 17 million tons. [15]

In the United States, Europe, and Japan, consumption of calcium carbide is generally declining. [16] Production levels in the US during the 1990s were 236,000 tons per year. [13]

Production of calcium cyanamide

Calcium carbide reacts with nitrogen at high temperature to form calcium cyanamide: [5]

CaC2 + N2 → CaCN2 + C

Commonly known as nitrolime, calcium cyanamide is used as fertilizer. It is hydrolysed to cyanamide, H2NCN. [5]

Steelmaking

Calcium carbide is used:

Carbide lamps

Lit carbide lamp Carbide lamp lit.jpg
Lit carbide lamp

Calcium carbide is used in carbide lamps. Water dripping on carbide produces acetylene gas, which burns and produces light. While these lamps gave steadier and brighter light than candles, they were dangerous in coal mines, where flammable methane gas made them a serious hazard. The presence of flammable gases in coal mines led to miner safety lamps such as the Davy lamp, in which a wire gauze reduces the risk of methane ignition. Carbide lamps were still used extensively in slate, copper, and tin mines where methane is not a serious hazard. Most miners' lamps have now been replaced by electric lamps.

Carbide lamps are still used for mining in some less wealthy countries, for example in the silver mines near Potosí, Bolivia. Carbide lamps are also still used by some cavers exploring caves and other underground areas, [17] although they are increasingly being replaced in this use by LED lights.

Carbide lamps were also used extensively as headlamps in early automobiles, motorcycles and bicycles, but have been replaced entirely by electric lamps. [18]

Other uses

Calcium carbide is sometimes used as source of acetylene, which like ethylene gas, is a ripening agent. [19] However, this is illegal in some countries as, in the production of acetylene from calcium carbide, contamination often leads to trace production of phosphine and arsine. [20] [21] These impurities can be removed by passing the acetylene gas through acidified copper sulfate solution, but, in developing countries, this precaution is often neglected.

Calcium carbide is used in toy cannons such as the Big-Bang Cannon, as well as in bamboo cannons. In the Netherlands calcium carbide is used around new-year to shoot with milk churns. [22]

Calcium carbide, together with calcium phosphide, is used in floating, self-igniting naval signal flares, such as those produced by the Holmes' Marine Life Protection Association.

Calcium carbide is used to determine the moisture content of soil. When soil and calcium carbide are mixed in a closed pressure cylinder, the water content in soil reacts with calcium carbide to release acetylene whose pressure can be measured to determine the moisture content. [23] [24]

Calcium carbide is sold commercially as a mole repellent. [25] When it comes into contact with water, the gas produced drives moles away. [26]

Related Research Articles

<span class="mw-page-title-main">Acetylene</span> Hydrocarbon compound (HC≡CH)

Acetylene is the chemical compound with the formula C2H2 and structure H−C≡C−H. It is a hydrocarbon and the simplest alkyne. This colorless gas is widely used as a fuel and a chemical building block. It is unstable in its pure form and thus is usually handled as a solution. Pure acetylene is odorless, but commercial grades usually have a marked odor due to impurities such as divinyl sulfide and phosphine.

<span class="mw-page-title-main">Ethylene glycol</span> Organic compound ethane-1,2-diol

Ethylene glycol is an organic compound with the formula (CH2OH)2. It is mainly used for two purposes: as a raw material in the manufacture of polyester fibers and for antifreeze formulations. It is an odorless, colorless, flammable, viscous liquid. It has a sweet taste, but is toxic in high concentrations. This molecule has been observed in outer space.

<span class="mw-page-title-main">Ethane</span> Organic compound (H3C–CH3)

Ethane is a naturally occurring organic chemical compound with chemical formula C
2H
6. At standard temperature and pressure, ethane is a colorless, odorless gas. Like many hydrocarbons, ethane is isolated on an industrial scale from natural gas and as a petrochemical by-product of petroleum refining. Its chief use is as feedstock for ethylene production. The ethyl group is formally, although rarely practically, derived from ethane.

<span class="mw-page-title-main">Ethylene oxide</span> Cyclic compound (C2H4O)

Ethylene oxide is an organic compound with the formula C2H4O. It is a cyclic ether and the simplest epoxide: a three-membered ring consisting of one oxygen atom and two carbon atoms. Ethylene oxide is a colorless and flammable gas with a faintly sweet odor. Because it is a strained ring, ethylene oxide easily participates in a number of addition reactions that result in ring-opening. Ethylene oxide is isomeric with acetaldehyde and with vinyl alcohol. Ethylene oxide is industrially produced by oxidation of ethylene in the presence of a silver catalyst.

<span class="mw-page-title-main">Industrial processes</span> Process of producing goods

Industrial processes are procedures involving chemical, physical, electrical, or mechanical steps to aid in the manufacturing of an item or items, usually carried out on a very large scale. Industrial processes are the key components of heavy industry.

In chemistry, an acetylide is a compound that can be viewed as the result of replacing one or both hydrogen atoms of acetylene (ethyne) HC≡CH by metallic or other cations. Calcium carbide is an important industrial compound, which has long been used to produce acetylene for welding and illumination. It is also a major precursor to vinyl chloride. Other acetylides are reagents in organic synthesis.

<span class="mw-page-title-main">Carbide lamp</span> Acetylene-burning lamps

A carbide lamp or acetylene gas lamp is a simple lamp that produces and burns acetylene (C2H2), which is created by the reaction of calcium carbide (CaC2) with water (H2O).

<span class="mw-page-title-main">Calcium phosphide</span> Chemical compound

Calcium phosphide (CP) is the inorganic compound with the formula Ca3P2. It is one of several phosphides of calcium, being described as the salt-like material composed of Ca2+ and P3−. Other, more exotic calcium phosphides have the formula CaP / Ca2P2, CaP3, and Ca5P8.

<span class="mw-page-title-main">Calcium cyanamide</span> Chemical compound

Calcium cyanamide, also known as Calcium carbondiamide, Calcium cyan-2°-amide or Calcium cyanonitride is the inorganic compound with the formula CaCN2. It is the calcium salt of the cyanamide (CN2−
2) anion. This chemical is used as fertilizer and is commercially known as nitrolime. It also has herbicidal activity and in the 1950s was marketed as cyanamid. It was first synthesized in 1898 by Adolph Frank and Nikodem Caro (Frank–Caro process).

<span class="mw-page-title-main">Industrial gas</span> Gaseous materials produced for use in industry

Industrial gases are the gaseous materials that are manufactured for use in industry. The principal gases provided are nitrogen, oxygen, carbon dioxide, argon, hydrogen, helium and acetylene, although many other gases and mixtures are also available in gas cylinders. The industry producing these gases is also known as industrial gas, which is seen as also encompassing the supply of equipment and technology to produce and use the gases. Their production is a part of the wider chemical Industry.

<span class="mw-page-title-main">Cyanamide</span> Chemical compound featuring a nitrile group attached to an amino group

Cyanamide is an organic compound with the formula CN2H2. This white solid is widely used in agriculture and the production of pharmaceuticals and other organic compounds. It is also used as an alcohol-deterrent drug. The molecule features a nitrile group attached to an amino group. Derivatives of this compound are also referred to as cyanamides, the most common being calcium cyanamide (CaCN2).

<span class="mw-page-title-main">Kipp's apparatus</span> Laboratory device for preparing gases

Kipp's apparatus, also called a Kipp generator, is an apparatus designed for preparation of small volumes of gases. It was invented around 1844 by the Dutch pharmacist Petrus Jacobus Kipp and widely used in chemical laboratories and for demonstrations in schools into the second half of the 20th century.

Ammonia production takes place worldwide, mostly in large-scale manufacturing plants that produce 183 million metric tonnes of ammonia (2021) annually. Leading producers are China (31.9%), Russia (8.7%), India (7.5%), and the United States (7.1%). 80% or more of ammonia is used as fertilizer. Ammonia is also used for the production of plastics, fibres, explosives, nitric acid, and intermediates for dyes and pharmaceuticals. The industry contributes 1% to 2% of global CO
2. Between 18–20 Mt of the gas is transported globally each year.

<span class="mw-page-title-main">Frank–Caro process</span> Aka cyanamide process: nitrogen fixation reaction of calcium carbide with nitrogen gas

The Frank–Caro process, also called cyanamide process, is the nitrogen fixation reaction of calcium carbide with nitrogen gas in a reactor vessel at about 1,000 °C. The reaction is exothermic and self-sustaining once the reaction temperature is reached. Originally the reaction took place in large steel cylinders with an electrical resistance element providing initial heat to start the reaction. Modern production uses rotating ovens. The synthesis produces a solid mixture of calcium cyanamide (CaCN2), also known as nitrolime, and carbon.

<span class="mw-page-title-main">Silver acetylide</span> Chemical compound

Silver acetylide is an inorganic chemical compound with the formula Ag2C2, a metal acetylide. The compound can be regarded as a silver salt of the weak acid, acetylene. The salt's anion consists of two carbon atoms linked by a triple bond, thus, its structure is [Ag+]2[−C≡C−]. The alternate name "silver carbide" is rarely used, although the analogous calcium compound CaC2 is called calcium carbide. Silver acetylide is a primary explosive.

Copper(I) acetylide, Kupfercarbid or cuprous acetylide, is a chemical compound with the formula Cu2C2. Although never characterized by X-ray crystallography, the material has been claimed at least since 1856. One form is claimed to be a monohydrate with formula Cu
2C
2.H
2O is a reddish-brown explosive powder.

The oxidative coupling of methane (OCM) is a potential chemical reaction studied in the 1980s for the direct conversion of natural gas, primarily consisting of methane, into value-added chemicals. Although the reaction would have strong economics if practicable, no effective catalysts are known, and thermodynamic arguments suggest none can exist.

<span class="mw-page-title-main">Calcium cyanide</span> Chemical compound

Calcium cyanide is the inorganic compound with the formula Ca(CN)2. It is the calcium salt derived from hydrocyanic acid. It is a white solid, although the pure material is rarely encountered. It slowly hydrolyses in solution or moist air to release hydrogen cyanide and is very toxic.

Headspace gas chromatography uses headspace gas—from the top or "head" of a sealed container containing a liquid or solid brought to equilibrium—injected directly onto a gas chromatographic column for separation and analysis. In this process, only the most volatile substances make it to the column. The technique is commonly applied to the analysis of polymers, food and beverages, blood alcohol levels, environmental variables, cosmetics, and pharmaceutical ingredients.

<span class="mw-page-title-main">Steam cracking</span> Petrochemical process to break down saturated hydrocarbons in smaller molecules

Steam cracking is a petrochemical process in which saturated hydrocarbons are broken down into smaller, often unsaturated, hydrocarbons. It is the principal industrial method for producing the lighter alkenes, including ethene and propene. Steam cracker units are facilities in which a feedstock such as naphtha, liquefied petroleum gas (LPG), ethane, propane or butane is thermally cracked through the use of steam in steam cracking furnaces to produce lighter hydrocarbons. The propane dehydrogenation process may be accomplished through different commercial technologies. The main differences between each of them concerns the catalyst employed, design of the reactor and strategies to achieve higher conversion rates.

References

  1. 1 2 Konar, Sumit; Nylén, Johanna; Svensson, Gunnar; Bernin, Diana; Edén, Mattias; Ruschewitz, Uwe; Häussermann, Ulrich (2016). "The many phases of CaC2". Journal of Solid State Chemistry. 239. Elsevier BV: 204–213. Bibcode:2016JSSCh.239..204K. doi: 10.1016/j.jssc.2016.04.030 . ISSN   0022-4596.
  2. ↑ NFPA Hazard Rating Information for Common Chemicals. Northeastern University
  3. ↑ Patnaik, Pradyot (2003). Handbook of Inorganic Chemical Compounds. McGraw-Hill. ISBN   0-07-049439-8.
  4. ↑ Vincoli, Jeffrey Wayne (25 November 1996). Risk Management for Hazardous Chemicals. CRC Press. p. 429. ISBN   978-1-56670-200-3.
  5. 1 2 3 4 Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. p. 298. ISBN   978-0-08-037941-8.
  6. ↑ Calculated from data in the CRC Handbook of Chemistry and Physics.
  7. 1 2 Holzrichter, Klaus; Knott, Alfons; Mertschenk, Bernd; Salzinger, Josef (2013). "Calcium Carbide". Ullmann's Encyclopedia of Industrial Chemistry. pp. 1–14. doi:10.1002/14356007.a04_533.pub2. ISBN   978-3-527-30673-2.
  8. ↑ Freeman, Horace (1919). "Manufacture of Cyanamide". The Chemical News and the Journal of Physical Science. 117: 232.
  9. ↑ Morehead, J. T. and de Chalmot, G. (1896). "The Manufacture of Calcium Carbide". Journal of the American Chemical Society. 18 (4): 311–331. doi:10.1021/ja02090a001.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  10. ↑ Moissan, H. (1892). "Chimie Minérale – Description d'un nouveau four électrique". Comptes rendus hebdomadaires des séances de l'Académie des sciences. 115: 1031.
  11. ↑ Renouf, Edward (1899). "The use of Acetylene". Popular Science Monthly: 335–347.
  12. ↑ "Zgrada Prve hidrocentrale na Balkanu - Komisija za očuvanje nacionalnih spomenika". old.kons.gov.ba (in Serbo-Croatian). KONS . Retrieved 15 March 2019.
  13. 1 2 Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN   978-0-08-037941-8.
  14. ↑ Dun, Ya (2006-01-23). "Troubles in the PVC industry". Hong Kong Trade Development Council. Archived from the original on 2007-12-28.{{cite web}}: CS1 maint: bot: original URL status unknown (link)
  15. ↑ "Government takes measures to curb development of calcium carbide sector". China Daily via BusyTrade.com. 2007-05-16. Archived from the original on 2007-02-11.{{cite news}}: CS1 maint: bot: original URL status unknown (link)
  16. ↑ Lacson, Jamie; Schlag, Stefan; Toki, Goro (December 2004). "Calcium Carbide". SRI Consulting.
  17. ↑ "Caving equipment and culture (from Te Ara Encyclopedia of New Zealand)".
  18. ↑ Clemmer, Gregg (1987). American Miners' Carbide Lamps: A Collectors Guide to American Carbide Mine Lighting. Westernlore Publications.
  19. ↑ Abeles, F. B. and Gahagan, H. E. III (1968). "Abscission: The Role of Ethylene, Ethylene Analogues, Carbon Dioxide, and Oxygen". Plant Physiol. 43 (8): 1255–1258. doi:10.1104/pp.43.8.1255. PMC   1087003 . PMID   16656908.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  20. ↑ "Bet on it. Your mango is ripened using carbide". dna. 2013-05-18. Retrieved 2018-08-25.
  21. ↑ "Eating Artificially Ripened Fruits is Harmful".
  22. ↑ "Carbidschieten wordt feest" (in Dutch). Algemeen Dagblad. 2016-12-24.
  23. ↑ Singh, Randhir (17 December 2008). "Determining Water Content In Soil – Calcium Carbide Method". Civil Engineering Portal. Retrieved 7 September 2020.
  24. ↑ ASTM International. "ASTM D4944-18, Standard Test Method for Field Determination of Water (Moisture) Content of Soil by the Calcium Carbide Gas Pressure Tester". ASTM International. Retrieved 7 September 2020.
  25. ↑ du Bois, T.M.E. (20 February 2014). "Molehill Mayhem". p. 21. hdl:1874/290102. Archived from the original on 25 March 2022. Retrieved 15 January 2021.
  26. ↑ "How to Get Rid of Yard Moles With Carbide". mysunnylawn.com.
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