MaAlkanes: Maumbirwo uye Maitiro muOrganic Chemistry
Pendauluan
MaAlkanes ndiwo boka riri nyore kwazvo remahydrocarbon akazara mumakemikari eorganic. Anosanganisira maatomu ekabhoni (C) nehydrogen (H) chete akabatanidzwa ne single sigma (σ) bonds. Nefomura yakajairika CₙH₂ₙ₊₂ yemacompounds e aliphatic, maalkanes anowanzonzi maparaffin, kunyanya muindasitiri yemafuta negasi. Muchinyorwa chino, tichaongorora chimiro, mazita, hunhu hwepanyama nemakemikari, uye maitiro akakosha anosanganisira maalkanes.
Maumbirwo uye Mazita
MaAlkanes ane cheni dzekabhoni dzinogona kuva dzakatsetseka kana kuti dzakapatsanurwa. Maatomu ekabhoni ari mualkanes akagadzirwa se sp³ hybridized, zvichireva kuti atomu yega yega yekabhoni inoumba zvisungo zvina zve covalent, zvichikonzera chimiro che tetrahedral chine ma bond angles angangoita 109.5°.
Mazita eIUPAC (International Union of Pure and Applied Chemistry) e alkanes anobva pahuwandu hwemaatomu ekabhoni ari mumutsara wemusana. Tafura inotevera inopa mimwe mienzaniso:
– Methane (CH₄): atomu imwe chete yekabhoni
– Ethane (C₂H₆): maatomu maviri ekabhoni
– Propane (C₃H₈): maatomu matatu ekabhoni
– Butane (C₄H₁₀): maatomu mana ekabhoni
– Pentane (C₅H₁₂): maatomu mashanu ekabhoni
Kana cheni huru ine maatomu ekabhoni anopfuura mana, tinoshandisa musanganiswa wemazita zvichienderana nehuwandu hwemaatomu ekabhoni (semuenzaniso, hexane inomirira matanhatu, heptane inomirira manomwe, zvichingodaro).
Kune ma alkanes ane matavi, nhamba dzinotanga pamagumo echeni iri pedyo nebazi. Matavi aya, kana kuti anotsiva, anodomwa nemazita ealkyl, semuenzaniso, methyl (-CH₃) kana ethyl (-C₂H₅), uye nzvimbo yawo mucheni huru yekabhoni inoratidzwa nenhamba. Muenzaniso uri nyore i2-methylpropane (C₄H₁₀), inozivikanwawo se isobutane.
Zvimiro zvemuviri
MaAlkanes anowanzova asiri epolar nekuti maC-H bonds ane musiyano mudiki weelectronegativity. Nekuda kweizvozvo, anonyungudika muzvinhu zvisiri zvepolar asi haanyungudike mumvura. Semahydrocarbon akazara, nzvimbo dzawo dzekunyungudika nekudzivira dzinowedzera nekuwedzera kureba kwechain yekabhoni uye molecular mass. Semuenzaniso, methane, ethane, uye propane magasi ari patembiricha yemumba, nepo butane nepentane zviri zvinwiwa, uye maalkanes ane cheni refu anogona kuva solids mumamiriro ezvinhu akajairwa.
Chimwe chinhu chakakosha chemuviri ndeyekuwanda kwemvura. MaAlkanes anowanzova mashoma kupfuura mvura (1 g/cm³), zvichireva kuti anoyangarara kana akaiswa mumvura. Uyezve, maalkanes ane refractive index yakaderera uye haawanzo shanda ne ultraviolet kana chiedza chinoonekwa.
Hunhu hweMakemikari uye Maitiro
Pamakemikari, ma alkanes anowanzo shanda zvishoma pane mahydrocarbon asina kuguta akadai se alkenes ne alkynes. Zvisinei, kune mhando dzakasiyana dzemaitiro:
1. Kupisa: MaAlkanes anoita pamwe chete neokisijeni (O₂) mukuita kwekutsva kuti abudise kabhoni dhayokisaidhi (CO₂), mvura (H₂O), uye simba. Kuita uku kunogona kuratidzwa seizvi:
\[ \text{C}_n\text{H}_{2n+2} + \text{O}_2 \rightarrow \text{CO}_2 + \text{H}_2\text{O} + \text{Energy} \]
Kupisa kwakakwana kunoitika kana paine okisijeni yakakwana, nepo kupisa kusina kukwana kuchiburitsa kabhoni monoxide (CO) kana kunyange kabhoni (soot).
2. Kutsiva Radical: Mune mamwe mamiriro ezvinhu, ma alkanes anogona kuita nema halogens kuburikidza ne free radical mechanism. Muenzaniso ndewe chlorination ye methane, iyo inoitika muzvikamu zvitatu: kutanga, kupararira, uye kuguma, zvichigadzira chloromethane (CH₃Cl) sechigadzirwa chikuru:
\[ \text{CH}_4 + \text{Cl}_2 \rightarrow \text{CH}_3\text{Cl} + \text{HCl} \]
3. Kutsemuka: Maitiro aya anoshandiswa muindasitiri yemafuta kuputsa mamorekuru makuru ealkane kuita madiki, kusanganisira alkenes ne lower alkanes. Zvakakosha zvikuru mukugadzirwa kwemafuta nezvimwe zvigadzirwa zvemakemikari:
\[ \text{C}_{10}\text{H}_{22} \rightarrow \text{C}_8\text{H}_{18} + \text{C}_2\text{H}_4 \]
4. Kushandiswa kweIsomerization: Ma alkanes akatsetseka anogona kushandurwa kuita ma isomers ane branched uchishandisa acid catalysts. Izvi zvakakosha muindasitiri kuti mafuta ave nani nekuti ma alkanes ane branched ane ma octane akawanda.
Kushandiswa kweAlkanes
MaAlkanes ane mashandisirwo akasiyana-siyana muhupenyu hwezuva nezuva uye muindasitiri:
– Mafuta: Methane, ethane, propane, uye butane zvinoshandiswa segasi rechisikigo uye semafuta emvura. Semuenzaniso, propane inoshandiswa mumabhodhoro egasi ekushandisa mumba.
– Zvinhu Zvisina Kugadzirwa zveMakemikari: MaAlkanes zvinhu zvekugadzira mapurasitiki, zvinonyungudutsa, nezvimwe zvigadzirwa zvemakemikari zvakasiyana-siyana kuburikidza nemaitiro emakemikari akadai sekutsemuka uye polymerization.
– Mafuta Anozora uye Wakisi: Ma alkanes marefu anoshandiswa mumafuta anozora uye wakisi nekuda kwehunhu hwawo hwekuzora uye nzvimbo dzakanyanya kunyunguduka.
Mhedziso
MaAlkanes ndiwo mativi makuru emakemikari eorganic uye anoita basa rakakosha muindasitiri. Kubva pakuumbwa kwawo kwekutanga uye mazita kusvika pakuita kwawo uye mashandisirwo awo, kunzwisisa kwakakwana kwemaalkanes kwakakosha. Kusaita kwawo zvakanaka kunowanzoita kuti abatsire, asi zvakare ave akaoma, mukushandiswa kwemakemikari. Kuburikidza nehunyanzvi uye hunyanzvi hwakadai sekupwanya uye isomerization, tinogona kushandisa hunhu hwakasiyana hwemaalkanes kuti tisangane nezvinodiwa nesimba nezvinhu zvemazuva ano.
Nekushandiswa kwadzo kwakasiyana-siyana uye kukosha kwadzo, ma alkanes anoramba ari nyaya yekuenderera mberi nekudzidza nekushandiswa mumakemikari neindasitiri.
