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Baris 51: \|- \|} '''Asetilena''' ([[Tatanama IUPAC\|Nama sistematis]]: '''etuna''') adalah suatu [[hidrokarbon]] yang tergolong kepada [[alkuna]], dengan rumus [[karbon\|C<sub>2</sub>]][[hidrogen\|H<sub>2</sub>]]. Asetilena merupakan alkuna yang paling sederhana, karena hanya terdiri dari dua atom karbon dan dua [[atom hidrogen]]. Pada asetilena, kedua karbon [[ikatan kimia\|terikat]] melalui [[ikatan rangkap tiga]], dan masing-masing atom karbon memiliki [[hibridisasi orbital]] sp untuk [[ikatan sigma]]. Hal ini menyebabkan keempat atom pada asetilena terletak pada satu garis lurus, dengan sudut C-C-H sebesar 180°. Asetilena ditemukan oleh [[Edmund Davy]] pada [[1836]], yang menyebutnya ''[[karburet]]'' baru dari hidrogen. Nama asetilena diberikan oleh [[kimiawan]] [[~~Perancis~~Prancis]] [[Marcellin Berthelot]], pada [[1860]]. Pada [[1912]], sebuah ledakan asetilena membutakan [[fisikawan]] [[Gustaf Dalén]], yang kemudian pada tahun yang sama memperoleh [[hadiah Nobel]] di bidang [[fisika]].<ref>{{cite web \| url = http://nobelprize.org/nobel_prizes/physics/laureates/1912/dalen-bio.html \| title = Gustaf Dalén Baris 73: Asetilena juga dapat dihasilkan dengan reaksi [[pembakaran]] parsial [[metana]] dengan [[oksigen]] atau dengan reaksi ''[[cracking (kimia)\|cracking]]'' dari [[hidrokarbon]] yang lebih besar. Berthelot dapat membuat asetilena dari [[metanol]], [[etanol]], [[etilena]], atau [[eter]], dengan cara melewatkan gas atau uap dari salah satu zat tersebut melalui tabung merah panas. Berthelot juga menemukan asetilena dapat dibuat dengan cara memberikan kejutan listrik terhadap gas-gas [[sianogen]] dan [[hidrogen]]. Ia juga dapat membuat asetilena dengan mereaksikan hidrogen murni dan [[karbon]] secara langsung dengan menggunakan [[tegangan listrik]]. == Reaksi == Reaksi [[pirolisis]] asetilena dimulai pada temperatur 400 °C(673 K) (cukup rendah untuk hidrokarbon). Hasil utamanya adalah [[dimer]] [[vinilasetilena]] (C<sub>4</sub>H<sub>4</sub>) dan [[benzena]]. Pada temperatur di atas 900 °C(1173 K), hasil utama reaksi adalah [[jelaga]] (karbon hitam). Berthelot menunjukkan bahwa senyawa [[alifatik]] dapat diubah menjadi senyawa [[aromatik]], dengan memanaskan asetilena di dalam [[tabung reaksi]] menghasilkan [[benzena]] dan sedikit [[toluena]]. Berthelot juga [[oksidasi\|mengoksidasi]] asetilena menghasilkan [[asam asetat]] dan [[asam oksalat]]. Ia juga menemukan [[reduksi]] asetilena dengan hidrogen menghasilkan [[etilena]] dan [[etana]]. [[Polimerasi]] asetilena dengan [[katalis Ziegler-Natta]] menghasilkan lapisan [[poliasetilena]]. Poliasetilena, rantai molekul karbon dengan ikatan tunggal dan ganda berselang-seling, merupakan [[semikonduktor organik]] yang pertama sekali ditemukan; reaksi dengan [[iodin]] menghasilkan bahan yang amat [[konduktor\|konduktif]]. Baris 108: <!--==Penggunaan== Approximately 80 percent of the acetylene produced annually in the [[United States]] is used in chemical synthesis. The remaining 20 percent is used primarily for [[oxyacetylene]] [[gas welding]] and [[blowtorch\|cutting]] due to the high temperature of the flame; combustion of acetylene with oxygen produces a flame of over 3300 °C (6000 °F), releasing 11.8 [[Kilojoule\|kJ]]/g. Oxyacetylene is the hottest burning common fuel gas. <ref name="BOC">http://www.boc.com/products_and_services/by_product/acetylene/index.asp</ref>. [[Cyanogen]], a more exotic gas, produces a flame of over 4525°C (8180°F) when it burns in oxygen.<ref>{{Citation \| last = Thomas \| first =N. Baris 131: In former times a few towns used acetylene for lighting, including [[Tata (Hungary)\|Tata]] in [[Hungary]] where it was installed on [[24 July]] [[1897]], and [[North Petherton]], [[England]] in 1898. In modern times acetylene is sometimes used for [[carburization]] (that is, hardening) of [[steel]] when the object is too large to fit into a furnace. <ref name="BOC" /> Acetylene has been proposed as a carbon feedstock for [[molecular manufacturing]] using nanotechnology. Since it does not occur naturally, using acetylene could limit out-of-control self-replication. Baris 148: ===Toxic effects=== Inhaling acetylene may cause dizziness, headache and nausea. <ref name="HitCL">Muir, GD (ed.) 1971, ''Hazards in the Chemical Laboratory'', The Royal Institute of Chemistry, London.</ref> It may also contain toxic impurities: the [http://www.cganet.com/publication_detail.asp?id=G-1.1 Compressed Gas Association Commodity Specification for acetylene] has established a grading system for identifying and quantifying [[phosphine]], [[arsine]], and [[hydrogen sulfide]] content in commercial grades of acetylene in order to limit exposure to these impurities. The sulfur, phosphorus and arsenic are carryovers from the synthesis ingredient coke, an impure form of carbon and different, organic impurities would be expected from the thermal cracking of hydrocarbons source. While the impurities in acetylene can be toxic and even fatal, pure acetylene is of a very low toxicity (not counting the "narcotic" effects). Up to 80% percent, (''v''/''v'') acetylene has been administered to surgical patients as a [[general anaesthetic]]. The trade name for acetylene was "narcylene." It was used a fair amount experimentally in Germany in their impoverished 1920's, perhaps on several thousand patients. Medically, acetylene was considered to be nearly as safe as [[nitrous oxide]] and with a slightly higher potency, allowing for the use of higher percentages of oxygen in the blend; it is about 50% more potent. However, the use of acetylene and oxygen mixtures was dropped after several gas explosions inside patients' lungs. The energy of these explosions would be expected to exceed any of the flammable inhalation anesthetics due to the instability of the triple bond (cyclopropane would be nearly as bad). It was suggested that such an internal thorax explosion could not occur with air mixtures (without purified oxygen). Baris 166: ==Natural occurrence== Acetylene is a moderately common chemical in the universe, often associated with the atmospheres of [[gas giant]]s. <ref>{{cite press release \| publisher = [[W. M. Keck Observatory]] \| title = Precursor to Proteins and DNA found in Stellar Disk \| date = 20 Dec 2005 \| url = http://www.keckobservatory.org/article.php?id=39}}</ref> One curious discovery of acetylene is on [[Enceladus (moon)\|Enceladus]], a moon of [[Saturn]]. Natural acetylene is believed to form from either [[catalytic]] decomposition of long chain hydrocarbons or at temperatures ≥ 1,770 [[kelvin]]. Since such temperatures are highly unlikely on such a small distant body, this discovery is potentially suggestive of catalytic reactions within the moon, making it a promising site to search for prebiotic chemistry.<ref>{{cite web \| publisher = [[The Planetary Society]] \| author = Emily Lakdawalla \| title = LPSC: Wednesday afternoon: Cassini at Enceladus \| date = 17 Mar 2006 \| url = http://www.planetary.org/blog/article/00000498/}}</ref><ref>{{cite journal\|journal=[[Nature (journal)\|Nature]] \| volume=445 \| pages=376-377\| date= 25 Jan 2007\| doi = 10.1038/445376b\| title= Planetary science: Inside Enceladus\| author=John Spencer and David Grinspoon}}</ref> --> Baris 177: [[Kategori:Alkuna]] [[Kategori:Kimia peledak]] [[Kategori:Gas industri]] [[Kategori:Asetilena]] [[Kategori:Bahan bakar gas]] [[Kategori:Teknologi bahan bakar sintetis]] [[Kategori:Gas peledak]]