Nrog rau kev txhim kho ntawm kev kawm ntawm cov organic chemistry, ib chav kawm cais tau txawv ntawm ib pawg loj ntawm hydrocarbons - "alkynes". Cov tebchaw no feem ntau hu ua unsaturated hydrocarbons, uas muaj nyob rau hauv lawv cov qauv ib los yog ntau tshaj triple (lwm lub npe yog triple carbon-carbon los yog acetylene) bonds, uas txawv lawv los ntawm alkenes (compounds nrog ob daim ntawv cog lus).
Nyob rau hauv ntau qhov chaw, koj tuaj yeem nrhiav tau lub npe muaj txiaj ntsig zoo rau alkynes - acetylenic hydrocarbons, thiab tib lub npe rau lawv "cov seem" - acetylene radicals. Alkynes tau nthuav tawm hauv cov lus hauv qab no nrog lawv cov qauv qauv thiab ntau lub npe.
| qauv qauv | Nomenclature | |
| International IUPAC | Rational | |
| HC ≡ CH | ethyn, acetylene | acetylene |
| H3C‒C ≡ CH | propine | Ymethylacetylene |
| H3C ‒ CH2 ‒C≡CH | butin-1 | Yethylacetylene |
| H3C ‒ C≡C ‒CH3 | butin-2 | Ydimethylacetylene |
| H3C ‒ CH2 ‒ CH2 ‒C ≡ CH | pentin-1 | Ypropylacetylene |
| H3C ‒ CH2 ‒C ≡ C - CH3 | Pentin-2 | methylethylacetylene |
International thiab rational nomenclature
Alkynes hauv chemistry, raws li IUPAC nomenclature (transliteration los ntawm Lus Askiv. International Union ntawm Pure thiab Applied Chemistry), muab cov npe los ntawm kev hloov cov lus "-an" rau cov lus "-hauv" hauv lub npe ntawm cov txheeb ze alkane, piv txwv li ethane → ethyne (piv txwv 1).
Tab sis koj tuaj yeem siv cov npe tsim nyog, piv txwv li: ethylene → acetylene, propyne → methylacetylene (piv txwv 2), uas yog, muab lub npe ntawm cov radical nyob ze ntawm peb daim ntawv cog lus rau lub npe ntawm tus neeg sawv cev me ntawm lub homologous series.
Nws yuav tsum nco ntsoov tias thaum txiav txim siab lub npe ntawm cov tshuaj complex, qhov twg muaj ob thiab peb daim ntawv cog lus, tus lej yuav tsum yog qhov uas lawv tau txais tus lej tsawg tshaj plaws. Yog tias muaj kev xaiv ntawm qhov pib ntawm tus lej, ces lawv pib nrog ob daim ntawv cog lus, piv txwv li: pentene-1, -in-4 (piv txwv li 3).
Ib qho tshwj xeeb ntawm txoj cai no yog ob npaug thiab triple daim ntawv cog lus sib npaug ntawm qhov kawg ntawm cov saw hlau, xws li, piv txwv li, hauv cov molecule ntawm hexadiene-1, 3, -in-5 (piv txwv 4). Nws yuav tsum nco ntsoov ntawm no tias cov lej xov tooj yuav pib nrog ob daim ntawv cog lus.
Rau cov saw ntev alkynes (ntau tshaj С 5 -С 6) nws raug pom zoo kom sivIUPAC thoob ntiaj teb nomenclature.
Tus qauv ntawm lub molecule nrog daim ntawv cog lus triple
Qhov piv txwv feem ntau ntawm cov qauv ntawm acetylenic hydrocarbon molecule yog nthuav tawm rau ethine, cov qauv uas tuaj yeem pom hauv lub rooj ntawm alkynes. Txhawm rau kom nkag siab yooj yim, daim duab qhia ntxaws ntxaws ntawm kev sib cuam tshuam ntawm cov pa roj carbon atom hauv acetylene molecule yuav muab rau hauv qab no.
Tus qauv dav dav ntawm ib qho alkyne yog C2H2. Yog li ntawd, hauv txheej txheem ntawm kev tsim ib daim ntawv cog lus triple 2 carbon atoms koom nrog. Txij li thaum carbon yog tetravalent - lub xeev zoo siab ntawm lub atom - nyob rau hauv cov organic tebchaw, muaj 4 unpaired electrons nyob rau hauv lub sab nrauv orbital - 2s thiab 2p3 (Fig. 1a). Nyob rau hauv tus txheej txheem ntawm kev tsim ib daim ntawv cog lus, ib tug hybrid huab yog tsim los ntawm electron huab ntawm lub s- thiab ib tug p-orbital, uas yog hu ua sp-hybrid huab (Fig. 1b). Cov huab hybrid nyob rau hauv ob qho tib si carbon atoms yog tsom rau ib tug axis, uas ua rau lawv linear kev npaj (ntawm ib lub kaum sab xis ntawm 180 °) txheeb ze rau ib leeg nrog rau qhov me me sab nraud (Fig. 2). Electrons nyob rau hauv feem ntau ntawm cov huab, thaum txuas, tsim ib tug electron khub thiab tsim ib tug σ-bond (sigma bond, Fig. 1c).
Lub tshuab hluav taws xob tsis sib xws, nyob rau hauv qhov me me, txuas tib lub electron rau hydrogen atom (Fig. 2). Qhov seem 2 unpaired electrons nyob rau sab p-orbital ntawm ib lub atom cuam tshuam nrog 2 lwm yam electrons ntawm lub thib ob atom. Nyob rau hauv cov ntaub ntawv no, txhua khub ntawm ob p-orbitals overlaps raws li π-bond txoj cai (pi-bond, Fig. 1d) thiab ua oriented txheeb ze.lwm qhov ntawm lub kaum sab xis 90 °. Tom qab txhua qhov kev sib cuam tshuam, cov huab dav dav siv cov duab cylindrical (Daim duab 3).
Lub cev muaj zog ntawm alkynes
Acetylene hydrocarbons zoo ib yam li alkanes thiab alkenes. Nyob rau hauv cov xwm, lawv xyaum tsis tshwm sim, tsuas yog rau ethine, yog li ntawd lawv tau txais artificially. Tsawg alkynes (txog C17) yog cov roj tsis muaj xim thiab kua. Cov no yog cov khoom qis-polar, vim tias lawv tsis zoo soluble hauv dej thiab lwm yam polar solvents. Txawm li cas los xij, lawv yaj zoo hauv cov organic yooj yim xws li ether, naphtha lossis benzene, thiab qhov peev xwm no txhim kho nrog nce siab thaum compressing cov pa. Cov neeg sawv cev siab tshaj plaws ntawm chav kawm no (C17 thiab siab dua) yog cov tshuaj crystalline.
Nyeem ntxiv txog cov khoom ntawm acetylene
Vim tias acetylene yog siv ntau tshaj plaws thiab siv dav, lub cev ntawm alkyne tau nkag siab zoo. Nws yog cov roj tsis muaj xim nrog cov tshuaj purity thiab tsis muaj ntxhiab tsw. Technical ethine muaj ntxhiab tsw vim muaj ammonia NH3, hydrogen sulfide H2S thiab hydrogen fluoride HF. Cov roj liquefied los yog gaseous no yog heev tawg thiab ignites yooj yim txawm los ntawm static paug los ntawm cov ntiv tes. Tsis tas li ntawd, vim nws lub cev muaj zog, alkyne, tov nrog oxygen, muab qhov kub thiab txias ntawm 3150 ° C, uas ua rau nws muaj peev xwm siv acetylene ua cov roj combustible zoo hauv vuam thiab txiav hlau. Acetylene muaj tshuaj lom, yog li yuav tsum tau saib xyuas hnyav thaum ua haujlwm nrog cov roj no.
Acetylene dissolves zoo tshaj plaws hauv acetone, tshwj xeeb tshaj yog nyob rau hauv lub xeev liquefied, yog li ntawd, thaum muab cia rau hauv lub xeev ua kua, tshwj xeeb cylinders yog siv ntim nrog ib tug ntxeem tau loj nrog tusyees faib acetone nyob rau hauv siab txog li 25 MPa.
Thiab thaum siv nyob rau hauv lub xeev gaseous, cov roj tso tawm los ntawm cov kav dej tshwj xeeb, coj los ntawm kev tswj hwm thiab cov ntaub ntawv qhia kev thiab GOST 5457-75 "Acetylene yaj thiab roj gaseous technical. Specifications", uas piav qhia txog cov qauv ntawm alkyne thiab tag nrho cov txheej txheem rau kev txheeb xyuas thiab khaws cia ntawm cov pa roj carbon monoxide saum toj no.
Kev tsim cov acetylene
Ib txoj hauv kev yog ib feem ntawm thermal oxidation ntawm methane CH 4 nrog oxygen ntawm qhov kub ntawm 1500 ° C. Cov txheej txheem no tseem hu ua thermal oxidative cracking. Cov txheej txheem zoo sib xws tshwm sim thaum lub sij hawm oxidation ntawm methane nyob rau hauv ib qho hluav taws xob arc ntawm qhov kub siab tshaj 1500 ° C nrog ceev ceev ntawm cov pa roj carbon monoxide evolved, vim vim lub cev muaj zog ntawm alkyne, acetylene nyob rau hauv ib tug sib tov nrog unreacted methane yuav provoke ib tug tawg. Tsis tas li, cov khoom no tuaj yeem tau txais los ntawm kev ua haujlwm calcium carbide CaC2 thiab dej ntawm 2000 °C.
Daim ntawv thov
Ntawm cov homologues, raws li tau piav qhia saum toj no, tsuas yog acetylene tau txais kev siv loj thiab siv mus tas li, thiab nws tau tsim keeb kwm tias lub npe rational siv hauv kev tsim khoom.
Vim nws lub cev thiab tshuaj lom neegcov khoom thiab ib txoj kev pheej yig ntawm kev tau txais cov hydrocarbon no yog siv los tsim ntau yam organic solvents, hluavtaws rubbers thiab polymers.
