Copper(I) acetylide
<templatestyles src="Chembox/styles.css"/>
Template:Chembox image cellTemplate:Chembox AllOtherNamesTemplate:Chembox headerbarTemplate:Chembox IndexlistTemplate:Chembox JmolTemplate:Chembox ChEMBLTemplate:Chembox ECHATemplate:Chembox E numberTemplate:Chembox IUPHAR ligandTemplate:Chembox UNIITemplate:Chembox CompToxTemplate:Chembox headerbarTemplate:Chembox headerbarTemplate:Chembox OHS (set)Template:Chembox setHeaderTemplate:Chembox setDatarowTemplate:Chembox setDatarowTemplate:Chembox setDatarowTemplate:Chembox Datapage checkTemplate:Chembox Footer| Template:Longitem | Template:Unbulleted list |
| ChEBI | Template:Unbulleted list |
| ChemSpider | Template:Unbulleted list |
| DrugBank | Template:Unbulleted list |
| EC Number | Template:Unbulleted list |
| KEGG | Template:Unbulleted list |
| Template:Longitem | Template:Unbulleted list |
| RTECS number | Template:Unbulleted list |
| Script error: No such module "collapsible list". | |
| Script error: No such module "collapsible list". | |
| Template:Longitem | Template:Chem2 |
| Molar mass | Template:Chem molar mass |
| Appearance | red-brown powder |
Template:Chembox Footer/trackingScript error: No such module "TemplatePar".Template:Short description
Copper(I) acetylide, copper carbide or cuprous acetylide, is a chemical compound with the formula Template:Chem2. It is a copper(I) salt of acetylene. It consists of Template:Chem2 cations and acetylide anions Template:Chem2, with the triple bond between the two carbon atoms. Although never characterized by X-ray crystallography, the material has been claimed at least since 1856.[2] One form is claimed to be a monohydrate with formula Template:Chem2. Copper(I) acetylide is a reddish-brown explosive powder.
Synthesis
Materials purported to be copper acetylide can be prepared by treating acetylene with a solution of copper(I) chloride and ammonia:
This reaction produces a reddish solid precipitate.
Properties
When dry, copper acetylide is a heat and shock sensitive primary explosive, more sensitive than silver acetylide.[3]
In acetylene manufacturing plants, copper acetylide is thought to form inside pipes made of copper or an alloy with high copper content, which may result in violent explosion.[4] This led to abandonment of copper as a construction material in such facilities.[5] Copper catalysts used in the chemical industry can also possess a degree of risk under certain conditions.[6]
Reactions
Copper(I) acetylide is the substrate of Glaser coupling for the formation of polyynes. In a typical reaction, a suspension of Template:Chem2 in an amoniacal solution is treated with air. The copper is oxidized to Template:Chem2 and forms a blue soluble complex with the ammonia, leaving behind a black solid residue. The latter has been claimed to consist of carbyne, an elusive allotrope of carbon:[7]
This interpretation has been disputed.[8]
Freshly prepared copper(I) acetylide reacts with hydrochloric acid to form acetylene and copper(I) chloride. Samples that have been aged with exposure to air or to copper(II) ions liberate also higher polyynes Template:Chem2, with n from 2 to 6, when decomposed by hydrochloric acid. A "carbonaceous" residue of this decomposition also has the spectral signature of Template:Chem2 chains. It has been conjectured that oxidation causes polymerization of the acetylide anions Template:Chem2 in the solid into carbyne-type anions. Template:Chem2 or cumulene-type anions Template:Chem2.[2]
Thermal decomposition of copper(I) acetylide in vacuum is not explosive and leaves copper as a fine powder at the bottom of the flask, while depositing a fluffy very fine carbon powder on the walls. On the basis of spectral data, this powder was claimed to be carbyne Template:Chem2 rather than graphite as expected.[2]
Applications
Though not practically useful as an explosive due to high sensitivity, it is interesting as a curiosity because it is one of the very few explosives that do not liberate any gaseous products upon detonation.
The formation of copper(I) acetylide when a gas is passed through a solution of copper(I) chloride is used as a test for the presence of acetylene.
Reactions between Template:Chem2 and alkynes occur only if a terminal hydrogen is present (as it is slightly acidic in nature). Thus, this reaction is used for identification of terminal alkynes.
See also
References
<templatestyles src="Reflist/styles.css" />
- ↑ a b c Script error: No such module "citation/CS1".
- ↑ a b c Franco Cataldo (1999), From dicopper acetylide to carbyne.Polymer International, volume 48, issue 1, pages 15-22. Script error: No such module "CS1 identifiers".
- ↑ Script error: No such module "Citation/CS1".
- ↑ Script error: No such module "citation/CS1".
- ↑ Script error: No such module "citation/CS1".
- ↑ Script error: No such module "citation/CS1".
- ↑ Franco Cataldo (1999), ' 'A study on the structure and electrical properties of the fourth carbon allotrope: carbyne. Polymer International, volume 44, issue 2, pages 191–200. Script error: No such module "CS1 identifiers".
- ↑ H. Kroto (2010), Carbyne and other myths about carbon. RSC Chemistry World, November 2010.
Script error: No such module "Check for unknown parameters".
Script error: No such module "navbox". Template:Carbides