Cov kev mis rau alkenes. Properties thiab characterization ntawm alkenes

Cov feem ntau yooj yim organic tebchaw xws li nyeem thiab unsaturated hydrocarbons. Cov no muaj xws tshuaj ntawm cov chav kawm ntawv alkanes, alkynes, alkenes.

Cov mis uas muaj xws li hydrogen thiab cov pa roj carbon atoms nyob rau hauv ib lub ib theem zuj zus thiab kom muaj nuj nqis. Lawv feem ntau pom nyob rau hauv cov xwm.

Kev txiav txim ntawm alkenes

Lwm yam lawv lub npe - los yog hydrocarbons olefins ethylene. Nws yog li ntawd hu ua hauv chav kawm ntawv ntawm tebchaw active nyob rau hauv lub 18th xyoo pua qhia thaum qhib oily kua - ethylene chloride.

Los ntawm alkenes yog tshuaj muaj li ntawm cov pa roj carbon thiab hydrogen ntsiab. Lawv mus rau lub acyclic hydrocarbons. Cov molecules yog tam sim no tsuas muab ob npaug rau (unsaturated) daim ntawv cog lus txuas ob tug carbon atoms rau txhua lwm yam.

mis alkenes

Txhua chav kawm ntawv ntawm tebchaw muaj ib yam tshuaj los. Cov cim yog hais txog qhov periodic system qhia cov muaj pes tsawg leeg thiab qauv ntawm cov kev twb kev txuas ntawm txhua substance.

Cov kev mis ntawm alkenes denoted raws li nram no: C _n H _2n, qhov twg tus xov tooj n yog ntau dua los yog sib npaug zos rau 2. Yog hais tias deciphering nws yuav pom tias txhua carbon atom muaj ob hydrogen atoms.

Molecular mis alkenes ntawm lub homologous series sawv cev los ntawm cov hauv qab no lug: C ₂ H _4, C ₃ H _6, C ₄ H _8, C ₅ H _10, C ₆ H _12, C ₇ H _14, C ₈ H _16, C ₉ H _18, C ₁₀ H _20. Nws yuav pom tias txhua successive hydrocarbon muaj ib tug ntau carbon nyob rau 2 thiab ntau hydrogen.

Muaj yog ib tug graphical qhov chaw cim thiab qhov kev txiav txim ntawm tshuaj tebchaw ntawm atoms nyob rau hauv lub molecule, uas qhia tau hais tias cov yam ntxwv mis ntawm alkenes. Nrog kev pab los ntawm valence qhia los ntawm cov pa roj carbon thiab hydrogen.

Alkenes yam ntxwv mis tej zaum yuav muab tso tawm kom nyob rau hauv lub txhab daim ntawv no, thaum qhia, tag nrho cov tshuaj hais thiab kev sib txuas. Ib tug ntau cos qhia yog tsis qhia olefins carbon compound thiab hydrogen los ntawm txoj kev valence.

Formula skeletal xaiv qhov nyuaj qauv. Tawg kab sawv cev rau lub hauv paus ntawm lub molecule nyob rau hauv uas cov pa roj carbon atoms yog nyob nrog nws yav toj txiav thiab xaus, thiab hydrogen point mus.

Yuav ua li cas rau lub npe ntawm olefins

Raws li cov systematic nomenclature, mis thiab cov npe ntawm cov alkenes los ntawm alkanes tshwm sim tawm lub qauv hais txog nyeem hydrocarbons. Ua li no nyob rau hauv lub npe ntawm tus xeem suffix -Tus hloov los ntawm -ilen los yog -en. Ib qho piv txwv yog tus tsim ntawm butane-butylene thiab pentene los ntawm pentane.

Yuav kom qhia tau tias txoj hauj lwm txheeb ze rau lub ob kev twb kev txuas ntawm cov pa roj carbon atoms qhia nyob rau hauv Arabic numerals nyob rau hauv lub kawg ntawm lub npe.

Hauv plawv ntawm cov npe ntawm alkenes yog lub los ntawm lub hydrocarbon nrog tus coos saw nyob rau hauv uas lub ob daim ntawv cog lus yog tam sim no. Thaum lub sij hawm pib numbering lub saw yog feem ntau xaiv kawg uas yog ze tshaj rau tus unsaturated compound, carbon atoms.

Yog hais tias tus yam ntxwv mis ntawm alkenes muaj ceg uas qhia radicals lub npe thiab tus xov tooj, thiab muab lawv tug lej tom qab coj qhov chaw nyob rau hauv cov pa roj carbon saw. Raws li los ntawm lub npe ntawm tus hydrocarbon. Tom qab cov xov tooj no feem ntau yog muab tso rau ib tug hyphen.

Muaj unsaturated radical offshoots. Lawv cov npe yuav ua tau tsis tseem ceeb los yog ua los ntawm cov kev cai ntawm kev nomenclature.

Piv txwv li, NSC = CH- xa ethenyl los yog yas.

isomers

Molecular mis alkenes tej zaum yuav tsis qhia lub isomerism. Txawm li cas los, rau cov hoob kawm no ntawm tshuaj, tsuas yog cov ethylene qauv xam qhovkev spatial variation.

Isomers ethylenic hydrocarbons yuav ua tau rau cov pa roj carbon lub cev pob txha, ntawm unsaturated kev sib txuas lus txoj hauj lwm interclass los yog spatial.

Cov kev mis ntawm alkenes txiav txim seb tus nqi ntawm cov pa roj carbon thiab hydrogen atoms nyob rau hauv cov saw hlau, tab sis tsis qhia tus xub ntiag thiab qhov chaw nyob ntawm ib tug muab ob npaug rau daim ntawv cog lus nyob rau ntawd. Ib qho piv txwv yog lub cyclopropane raws li ib tug ntoo khaub lig-class isomer C ₃ H ₆ (propylene). Lwm yam hom isomerism, yog qhia nyob C ₄ H ₈ los yog butene.

Lwm Yam unsaturated kev sib txuas lus raws li txoj cai no tshwm sim nyob rau hauv lub butene-1 los yog butene-2, nyob rau hauv thawj cov ntaub ntawv, ib tug muab ob npaug rau kev twb kev txuas yog nyob ze ntawm lub thawj carbon atom, thiab nyob rau hauv lub thib ob - nyob rau hauv nruab nrab ntawm lub saw. Isomers ntawm carbon lub cev pob txha tau raug xam tias yog piv txwv li methylpropene (CH ₃ C (CH ₃₎ = CH ₂₎ thiab isobutylene _((CH3) 2C = CH _2).

Spatial variation xam qhovkev butene-2 thiab cis-trans txoj hauj lwm. Nyob rau hauv rooj plaub thawj sab pawg neeg nyob saum toj no thiab hauv qab no lub ntsiab carbon saw nrog ib tug muab ob npaug rau daim ntawv cog lus nyob rau hauv lub thib ob isomer substituents yog nyob rau tib sab.

Cov yam ntxwv ntawm olefins

Cov kev mis rau alkenes txiav txim lub cev kev mob ntawm tag nrho cov mej zeej ntawm lub chav kawm ntawv. Pib thiab xaus nrog ethylene butylene (C ₂ mus rau C _4), tshuaj muaj nyob rau hauv ib tug gaseous daim ntawv. Yog li ntawd tsis muaj kob ethene muaj sweetish tsw, tsis tshua muaj solubility nyob rau hauv dej, molecular yuag tsawg tshaj li uas ntawm huab cua.

Nyob rau hauv cov kua daim ntawv no, hais hydrocarbons homologous lub sij hawm los ntawm C ₅ rau C _17. Pib nrog lub alkene muaj nyob rau hauv lub ntsiab saw ntawm 18 carbon atoms, ib txoj kev hloov ntawm lub cev lub xeev nyob rau hauv ib tug khoom daim ntawv.

Tag nrho olefins rank pluag solubility nyob rau hauv aqueous xov xwm, tab sis zoo nyob rau hauv cov organic xwm ntawm lub hnyav, xws li benzene los yog roj av. Lawv molecular luj yog tsawg tshaj li uas ntawm cov dej. Ua cov pa roj carbon saw ua rau ib qho kev nce nyob rau hauv kub yam ntxwv los ntawm melting thiab kub cov ntsiab lus ntawm cov tebchaw.

zog olefins

Lub Khoos Loos Tsev mis alkenes qhia tau hais tias lub xub ntiag ntawm ob daim ntawv cog lus nyob rau hauv lub cev pob txha thiab σ- ntawm π- txuas ob carbon atoms. Qhov no qauv ntawm cov molecule txiav txim nws tshuaj zog. Kev sib txuas lus-π yog xav tau tsis muaj zog heev, uas ua rau nws tau txov nws nrog lub tsim ntawm ob tug tshiab bonds-σ, uas yog tau raws li ib tug tshwm sim ntawm koom ib tug khub uas atoms. Lub unsaturated hydrocarbons yog electron hloov. Lawv coj ib feem nyob rau hauv cov txheej txheem ntawm electrophilic hom kev twb kev txuas.

Ib qho tseem ceeb tshuaj cov khoom teejtug uas alkenes yog ib tug halogenation txheej txheem nrog rau cov kev tso cai ntawm tebchaw xws digalogenoproizvodnym tshuaj. Halogen atoms yuav raug txuas mus rau lub compound los ntawm ob carbons. Ib qho piv txwv yog lub bromination ntawm propylene tsim lub 1,2-dibromopropane:

H ₂ C = CH-CH ₃ + Br ₂ → BrCH ₂ -CHBr-CH _3.

Qhov no neutralization txheej txheem xim nyob rau hauv bromine dej alkenes xam tau tias yog qhov zoo pov thawj ntawm lub xub ntiag ntawm ob daim ntawv cog lus.

Tseem ceeb tshua olifinov koom hydrogenation nrog rau qhov sib ntxiv ntawm hydrogen molecules nyob rau hauv qhov kev txiav txim ntawm catalyst co xws li platinum, palladium los yog npib tsib xee. Qhov no los tau nyob rau hauv hydrocarbons nrog ib tug nyeem daim ntawv cog lus. Formula alkanes, alkenes yog muab hauv qab no nyob rau hauv lub hydrogenation ntawm butene:

CH ₃ -CH ₂ -CH = CH ₂ + H ₂ → CH ₃ ^Ni -CH ₂ -CH ₂ -CH _3.

Tus txheej txheem ntawm kev koom halide molecules hu ua olefins
gidrogalogenirovaniem dua los ntawm cov cai, qhib Markovnikov. Ib qho piv txwv yog lub hydrobromination ntawm propylene tsim 2-bromopropane. Nws yog kev cob cog rua nrog lub hydrogen-carbon ob daim ntawv cog lus, uas yog suav hais tias yog feem ntau hydrogenated:

CH ₃ -CH = CH ₂ + HBr → CH ₃ -BrCH-CH _3.

alkenes dej tas li ntawd cov tshuaj tiv thaiv nrog acids yog hu ua co. Cov no ib tug qauv ntawm cov cawv 2-propanol :

CH ₃ -HC = CH ₂ + H ₂ O → CH ₃ -OHCH-CH _3.

Thaum raug rau alkenes sulfuric acid sulfonation txheej txheem tshwm sim:

CH ₃ -HC = CH ₂ + HO-OSO-OH → CH ₃ -CH ₃ CH-OSO ₂ -OH.

Cov tshuaj tiv thaiv hais nrog lub tsim ntawm acid esters, e.g., izopropilsernoy acid.

Alkenes raug rau oxidation thaum lub sij hawm lawv cov combustion nyob rau hauv qhov kev txiav txim ntawm oxygen mus rau tsim dej thiab carbon dioxide:

2CH ₃ -HC = CH ₂ + 9O ₂ → 6CO ₂ + 6H ₂ O.

Cov tshuaj tiv thaiv ntawm olefinic tebchaw thiab ib tug nta poov tshuaj permanganate nyob rau hauv cov tshuaj muab sawv mus rau ib tug qauv glycols los yog dihydric alcohols. Qhov no cov tshuaj tiv thaiv no kuj oxidising tsim ethylene glycol thiab tshuaj dawb tso tshuaj:

3H ₂ C = CH ₂ + 4H ₂ O + 2KMnO ₄ → 3OHCH-CHOH + 2MnO ₂ + 2KOH.

Alkene molecule tej zaum yuav muab kev koom tes nyob rau hauv lub polymerization nrog ib tug dawb radical los yog cationic-anionic mechanism. Nyob rau hauv thawj cov ntaub ntawv, nyob rau hauv tus ntawm peroxides tau polyethylene hom polymer.

Raws li rau qhov thib ob mechanism cationic catalysts yog cov acid thiab anionic ua hauj lawm yog organometallic polymer nrog qee stereoselective.

Yuav ua li cas yog alkanes

Lawv hu ua paraffins los yog txwv acyclic hydrocarbons. Lawv muaj ib tug linear los yog branched qauv, uas muaj tsuas ib bonds uas. Tag nrho cov neeg ntawm lub homologous series ntawm no hauv chav kawm ntawv muaj cov kev mis C _n H _{2n + 2.}

Nyob rau hauv lawv cov qauv muaj tsuas carbon thiab hydrogen atoms. Cov kev mis ntawm lub alkene tsim cim nyeem hydrocarbons.

Lub npe ntawm alkanes thiab lawv cov yam ntxwv

Qhov yooj yim tus neeg sawv cev ntawm cov hoob kawm no yog methane. Raws li los ntawm tshuaj xws li ethane, hluav taws roj zeb thiab butane. Lub hauv paus ntawm lawv lub npe yog lub hauv paus ntawm lub tus nab npawj nyob rau hauv lub Greek lus, uas yog ntxiv lub suffix -Tus. Alkanes npe muaj nyob rau hauv IUPAC nomenclature.

Cov kev mis rau alkenes, alkynes, alkanes muaj xws li tsuas yog ob tug hom ntawm atoms. Cov muaj xws li cov ntsiab carbon thiab hydrogen. Tus nab npawb ntawm cov pa roj carbon atoms nyob rau hauv tag nrho peb cov chav kawm ntawv qhov yuam, zoo yog cai xwb nyob rau hauv lub xov tooj ntawm hydrogen uas yuav cleaved los yog koom nrog. Ntawm nyeem hydrocarbons tau unsaturated tebchaw. Cov neeg sawv cev ntawm lub paraffins muaj nyob rau hauv lub molecule yog 2 hydrogen atom ntau tshaj qhov olefin, uas tuaj yuav qhia ib tug dav dav mis ntawm alkanes, alkenes. Alkenes qauv yog suav tias yog vim muaj cov unsaturated ob daim ntawv cog lus.

Yog hais tias peb los sib piv cov naj npawb ntawm cov hydrogen thiab cov pa roj carbon atoms nyob rau hauv lub alkane, lub siab tshaj plaws nqi yuav muab piv nrog rau lwm cov chav kawm ntawm hydrocarbons.

Txij li thaum methane thiab xaus butane (C ₁ mus rau C _4), tshuaj muaj nyob rau hauv ib tug gaseous daim ntawv.

Nyob rau hauv cov kua daim ntawv no, hais hydrocarbons homologous lub sij hawm los ntawm C ₅ rau C _16. Txij li thaum alkane muaj nyob rau hauv lub ntsiab saw ntawm 17 carbon atoms, ib txoj kev hloov ntawm lub cev lub xeev nyob rau hauv ib tug khoom daim ntawv.

Lawv tsiag ntawv los ntawm isomerism ntawm cov pa roj carbon lub cev pob txha thiab kho qhov muag hloov ntawm lub molecule.

Lub paraffins carbon valences pom tau hais tias tag nrho nyob ib sab carbons los yog hydrogen tsim tau ib cov kev twb kev txuas σ-hom. Los ntawm ib tug tshuaj standpoint, qhov no ua rau lawv weaker zog, uas yog vim li cas alkanes yog hu ua kev txwv los yog nyeem hydrocarbons tsis affinity.

Lawv nkag mus rau hauv hloov tshua muaj feem xyuam rau halogenation los ntawm ib tug radical hom nitration sulfochlorination los yog molecule.

Paraffins yauv ib tug txheej txheem ntawm oxidation, combustion los yog decomposition sov siab. Nyob rau hauv qhov kev txiav txim accelerators cleavage tshua tshwm sim ib tug hydrogen atom los yog dehydrogenation ntawm alkanes.

Yuav ua li cas yog alkynes

Lawv kuj hu ua acetylene hydrocarbons, nyob rau hauv uas cov pa roj carbon yog tam sim no nyob rau hauv cov saw hlau triple daim ntawv cog lus. Tus qauv ntawm lub alkyne piav los ntawm cov kev mis C _n H _{2 n-2.} Nws yuav pom tias nyob rau hauv sib piv rau alkanes los ntawm acetylenic hydrocarbons lacks plaub hydrogen atoms. Lawv hloov lub triple daim ntawv cog lus, tsim los ntawm ob tug π- sib txuas.

Qhov no qauv txiav txim seb tus tshuaj thaj chaw ntawm no hauv chav kawm ntawv. Cov yam ntxwv mis ntawm alkenes thiab alkynes qha unsaturation ntawm lub lwg me me thiab muaj cov ob (H ₂ C꞊CH ₂₎ thiab triple (HC≡CH) kev twb kev txuas.

Lub npe alkynes thiab lawv cov yam ntxwv

Qhov yooj yim tus neeg sawv cev yog acetylene los yog HC≡CH. Nws kuj xa mus rau raws li ethynyl. Nws derives los ntawm lub npe ntawm tus nyeem hydrocarbon, uas tshem tawm cov suffix -Tus thiab ntxiv -Nyob rau hauv. Nyob rau hauv lub npe ntawm ntev-alkyne daim duab qhia rau qhov chaw ntawm lub triple daim ntawv cog lus.

Paub cov qauv ntawm cov hydrocarbon nyeem thiab unsaturated, nws yuav tsum tau txiav txim nyob rau hauv ib tsab ntawv qhia cov kev mis rau alkynes: a) CnH2n; a) CnH2n + 2; c) CnH2n-2; g) CnH2n-6. Cov lus teb yog cov kev xaiv thib peb.

Pib los ntawm acetylene thiab xaus butane (C ₂ mus rau C _4), tshuaj yog gaseous nyob rau hauv cov xwm.

Nyob rau hauv cov kua daim ntawv hydrocarbons yog homologous lub sij hawm los ntawm C ₅ rau C _17. Pib nrog alkyne muaj nyob rau hauv lub ntsiab saw ntawm 18 carbon atoms, ib txoj kev hloov ntawm lub cev lub xeev nyob rau hauv ib tug khoom daim ntawv.

Lawv tsiag ntawv los ntawm isomerism ntawm cov pa roj carbon lub cev pob txha, nyob rau hauv raws li txoj cai ntawm kev sib txuas lus triple thiab interclass modifying molecule.

Los ntawm cov tshuaj yam ntxwv zoo xws acetylenic hydrocarbons alkenes.

Yog hais tias lub davhlau ya nyob twg alkyne triple daim ntawv cog lus, lawv khiav lag luam tsim ib qho acid muaj nuj nqi alkinidov ntsev, e.g., NaC≡CNa. Lub xub ntiag ntawm lub ob π-bonds ua rau cov molecule ib tug muaj zog nucleophile sodium atsetiledina nkag mus rau hauv hloov tshua.

Acetylene yog chlorinated nyob rau hauv lub xub ntiag ntawm tooj liab chloride kom tau dichloroacetyl, hws nyob rau hauv qhov kev txiav txim ntawm ib tug tso tawm haloalkynyl diacetylenic molecules.

Alkynes koom nyob rau hauv electrophilic tas li ntawd tshua, lub hauv paus ntsiab lus uas underlies cov halogenation gidrogalogenirovaniya, co thiab carbonylation. Txawm li cas los, xws dab yog weaker dua cov alkenes nrog ib tug muab ob npaug rau daim ntawv cog lus.

Rau acetylenic hydrocarbons yuav nucleophilic tas li ntawd cov tshuaj tiv thaiv ntawm tus cawv hom molecule, ib tug thawj amine los yog sulfide.