Carbon tetrafluoride

Tetrafluoromethane, wanda kuma aka sani da carbon tetrafluoride ko R-14, shine mafi sauƙi perfluorocarbon ( C F 4 ). Kamar yadda sunan IUPAC ya nuna, tetrafluoromethane shine takwaransa mai gurbataccen ruwa zuwa methane na hydrocarbon. Hakanan ana iya rarraba shi azaman haloalkane ko halomethane . Tetrafluoromethane mai sanyi ne mai amfani amma kuma iskar gas mai ƙarfi.  Yana da ƙarfin haɗin gwiwa sosai saboda yanayin haɗin carbon-fluorine .

 jingina 
Saboda mahara carbon-fluorine bond, da kuma high electronegativity na fluorine, da carbon a tetrafluoromethane yana da wani gagarumin m m cajin wanda ya karfafa da kuma rage hudu carbon-fluorine bond ta samar da ƙarin ionic hali. Abubuwan haɗin carbon-fluorine sune mafi ƙarfi guda ɗaya a cikin sinadarai na halitta .  Bugu da ƙari, suna ƙarfafa yayin da ake ƙara ƙarin abubuwan haɗin carbon-fluorine zuwa carbon atom iri ɗaya. A cikin mahaɗin organofluorine guda ɗaya-carbon wanda ke wakiltar kwayoyin fluoromethane, difluoromethane, trifluoromethane, da tetrafluoromethane, haɗin carbon-fluorine sun fi karfi a cikin tetrafluoromethane.  Wannan tasirin ya faru ne saboda haɓakar abubuwan jan hankali na coulombic tsakanin atom ɗin fluorine da carbon saboda carbon yana da ingantaccen caji na 0.76. 

 Shiri 
Tetrafluoromethane shine samfurin lokacin da kowane fili na carbon, gami da carbon kanta, ya ƙone a cikin yanayin fluorine. Tare da hydrocarbons, hydrogen fluoride shine kwafi. An fara ba da rahoto a cikin 1926.  Hakanan za'a iya shirya shi ta hanyar fluorination na carbon dioxide, carbon monoxide ko phosgene tare da tetrafluoride sulfur . A kasuwanci ana kera shi ta hanyar amsawar hydrogen fluoride tare da dichlorodifluoromethane ko chlorotrifluoromethane ; Ana kuma samar da shi a lokacin electrolysis na karfe fluorides MF, MF 2 ta amfani da carbon electrode.

Ko da yake ana iya yin shi daga ɗimbin abubuwan precursors da fluorine, furotin na asali yana da tsada kuma yana da wuyar iyawa. A sakamakon haka, CF An shirya CF akan sikelin masana'antu ta amfani da hydrogen fluoride : 

 CCl 2 F 2 + 2 HF → CF 4 + 2 HCl

 Laboratory kira 
Ana iya shirya Tetrafluoromethane da silicon tetrafluoride a cikin dakin gwaje-gwaje ta hanyar amsawar silicon carbide tare da fluorine.

 SiC + 4 F 2 → CF 4 + SiF 4

 Martani 
Tetrafluoromethane, kamar sauran fluorocarbons, yana da ƙarfi sosai saboda ƙarfin haɗin gwiwar carbon-fluorine. Abubuwan da ke cikin tetrafluoromethane suna da ƙarfin haɗin gwiwa na 515 kJ⋅mol -1 . A sakamakon haka, shi ne inert zuwa acid da hydroxides. Duk da haka, yana mayar da martani tare da karafa na alkali . Rushewar thermal ko konewar CF 4 yana samar da iskar gas mai guba ( carbonyl fluoride da carbon monoxide ) kuma a gaban ruwa kuma zai samar da hydrogen fluoride .

Yana da ɗan narkewa sosai cikin ruwa (kimanin 20 mg⋅L -1 ), amma sosai mai narkewa a cikin kwayoyin kaushi. Lokacin da ruwa ya cika, yana da gaba ɗaya miscible a cikin kwayoyin kaushi.

 Amfani 
Tetrafluoromethane wani lokaci ana amfani dashi azaman mai sanyi mai ƙarancin zafin jiki (R-14). Ana amfani da shi a cikin microfabrication na lantarki kadai ko a hade tare da oxygen a matsayin wani abu na plasma don silicon, silicon dioxide, da silicon nitride .  Har ila yau, yana da amfani a cikin injin gano neutron. 

 Tasirin muhalli 
Tetrafluoromethane shine iskar gas mai ƙarfi wanda ke ba da gudummawa ga tasirin greenhouse . Yana da karko sosai, yana da tsawon rayuwa na yanayi na shekaru 50,000, kuma yana da yuwuwar dumamar yanayi sau 6,500 fiye da na CO 2 . 

Tetrafluoromethane shine mafi yawan perfluorocarbon a cikin yanayi, inda aka sanya shi a matsayin PFC-14. Matsayinta na yanayi yana girma:  ƙaddamarwar masana'antu na farko da aka samar ta hanyar iskar oxygen oxidation na fluorite da amsawa tare da kwayoyin halitta bai wuce sassa 40 a kowace tiriliyan ba.   Tun daga shekarar 2019, iskar gas da mutum ya yi CFC-11 da CFC-12 suna ci gaba da ba da gudummawar daɗaɗɗa mai ƙarfi fiye da PFC-14. 

Ko da yake tsarin yana kama da chlorofluorocarbons (CFCs), tetrafluoromethane ba ya rage ledar sararin samaniya  saboda haɗin carbon-fluorine ya fi wannan ƙarfi tsakanin carbon da chlorine. 

Babban watsin masana'antu na tetrafluoromethane ban da hexafluoroethane ana samar da su yayin samar da aluminium ta amfani da tsarin Hall-Héroult . Hakanan ana samar da CF 4 azaman samfur na rushewar hadaddun mahadi kamar halocarbons . 

 Hadarin lafiya 
Saboda yawansa, tetrafluoromethane na iya kawar da iska, yana haifar da haɗarin asphyxiation a wuraren da ba su da isasshen iska. In ba haka ba, yawanci ba shi da lahani saboda kwanciyar hankali.

 Manazarta 

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