Unsaturated hydrocarbons: alkenes, tshuaj zog thiab daim ntawv thov

Alkenes - unsaturated hydrocarbons uas nws molecules ntawm ob carbon atoms, ib tug muab ob npaug rau daim ntawv cog lus. Lawv feem ntau hu ua hydrocarbons ethylene series, vim hais tias nws yog ib tug yooj yim tus neeg sawv cev ethylene NC2 = CH2. Tej zaum cov hydrocarbons raug xa olefins li gaseous alkenes reacting nrog bromine los yog tshuaj mus rau daim ntawv oily tebchaw uas tsis soluble nyob rau hauv cov dej. Lo lus "alkenes" IUPAC nomenclature yog muab los ntawm lo lus "alkanes", qhov twg -Tus suffix yog hloov los ntawm cov tom qab -ene, uas qhia hauv lub xub ntiag nyob rau hauv lub molecule ntawm lub substance ntawm ob daim ntawv cog lus.

Unsaturated hydrocarbons - alkenes: qauv

Tag nrho alkenes xam tau tias yog derivatives ntawm ethylene los yog ethene - C2H4.

Lub ethylene molecule muaj ob carbon atoms thiab plaub hydrogen atoms, cov unsaturated carbon atoms. Txhua yam ntawm tus unsaturated carbon atom hybridizes ES ib tug thiab ob tug pi-orbitals, thiab ib tug pi orbital seem nyob rau hauv "dawb huv daim ntawv", uas muab nyiaj pab ntau tshaj deb ntawm hybridized hluav taws xob orbitals. lawv axes tsim 120 °. Qhov no ua ib qho kev pom tej yam kev mob rau lub overlap ntawm electron orbitals. Peb xws orbitals ntawm carbon atoms tsim peb sigma bonds (ob C-H, C-C a). Li ntawd, cov ethylene molecule muaj tsib sigma bonds uas yog laus nyob rau hauv tib lub dav hlau, txoj kev nruab nrab ntawm lawv ib tug kaum sab xis ntawm 120 °. P-electrons uas nyob twj ywm nyob rau hauv lub "dawb huv" tsim lwm daim ntawv cog lus ntawm ob tug carbon atoms. Piav hluav taws xob qauv ntawm ethylene molecules ntse alkenes. Unsaturated hydrocarbons yog yuav tsum tau kev raws li derivatives ntawm ethylene.

Rau alkene yus muaj los ntawm 2 hom isomerism - geometric thiab yam ntxwv.

Lub Khoos Loos Tsev isomers ntawm alkenes pib nrog butene C4H8. Paub qhov txawv thiab nws cov variants - saw isomerism (los yog cov pa roj carbon lub cev pob txha) thiab isomers kev tso kawm ntawm lub ob daim ntawv cog lus nyob rau hauv xws li ib tug Circuit Court.

Geometric isomerism vim sis tsis ncaj kev tso kawm ntawm hydrogen substituents nyob rau hauv lub molecule ntawm ethylene txheeb ze rau lub dav hlau ntawm lub ob daim ntawv cog lus. Unsaturated hydrocarbons yog cis- thiab trans-isomers.

Alkenes nyob rau hauv lub dawb lub xeev yog heev tsawg nyob rau hauv cov xwm. Lawv tsim siv industrial thiab kuaj dab.

Tshuaj thaj chaw ntawm hydrocarbons: alkenes

Lawv tshwm sim los ntawm ib tug muab ob npaug rau daim ntawv cog lus ntawm ob tug carbon atoms nyob rau hauv lub molecule ntawm ib tug alkene.

Lub hydrogenation cov tshuaj tiv thaiv

Alkenes hnov mob nkag Symptoms ntawm hydrogen. Nws tshwm sim nyob rau hauv lub xub ntiag ntawm catalysts los yog nrog cua kub:

CH2 = CH2 = H2 H3C CH3

koom halides

Cov tshuaj tiv thaiv tau nyaij los ntawm lub Markovnikov txoj cai, i.e. los ntawm reacting ib hydrogen halide nrog asymmetric molecules alkenes hydrogen yog ntxiv nyob rau qhov chaw ntawm lub chaw ntawm lub ob daim ntawv cog lus dua rau cov pa roj carbon atom tom ntej no mus uas muaj ntau ntau cov hydrogen atoms, ib tug halogen atom - mus cov pa roj carbon atom tom ntej no mus uas tsawg hydrogen atoms los yog kiag li lawv tsis nyob ua ib ke:

CH3-CH = CH2 + HC1-CH3-CH3-CHC1.

Kev siv ntawm hydrocarbons

Ethene - roj yaj zoo nyob rau hauv cawv thiab tsis zoo soluble nyob rau hauv dej, heev.

Lawv yog cov nplua nuj nyob rau hauv lub ntes gases (mus txog 20% ntawm tag nrho cov hnyav) thiab coke cub gas (kwv yees li 5%). Nyob rau hauv lub laboratory txoj kev lub cev qhuav dej ntawm ethylene npaj dehydrogenation ntawm ethane thiab ethanol. Thov kom tau ethylene ethyl cawv, yas chloride, ethylbenzyl, polyethylene, dej ntsuab agents (cov tshuaj uas txo lub freezing point ntawm cov dej nyob rau hauv xyaw) thiab lwm yam organic tshuaj. Nyob rau hauv tib neeg thiab kev kho tsiaj, ethylene yog siv raws li ib tug yeeb tshuaj formulation nyob rau hauv cov qoob loo - rau accelerate lub ripening ntawm txiv hmab txiv ntoo (txiv lws suav, txiv qaub, thiab cov zoo li).

Propylene yog tau ua ke nrog ethylene nyob rau hauv lub pyrolysis thiab ntes ntawm ntau hom ntawm cov roj av feedstock. Propylene - ib feem ntawm lub cev muaj zog roj. Nws yog siv raws li feedstock rau polypropylene, isopropylbenzyl, isopropyl haus dej cawv. Nrog isopropanol, acetone, nrog isopropylbenzyl - acetone thiab phenol. Propylene yog siv raws li ib tug narcotic tshuaj rau synthesizing acrylonitrile, cumene, butanol, etc.