Dawb radical Reaction

Txhais thiab qauv ntawm carbon dawb radicals
Thaum ib daim ntawv sib cais, nws tsim cov atoms lossis pawg nrog ib leeg electrons, uas yog hu ua dawb radicals. Ib qho dawb radical nrog ib leeg electron ntawm hydrogen atom hu ua hydrogen radical. Ib qho dawb radical nrog ib leeg electron ntawm cov pa roj carbon atom hu ua carbon radical. Ib qho hydrogen dawb radical thiab alkyl dawb radical (carbon dawb radical) yog tsim thaum CH daim ntawv cog lus hauv alkane yog homolysis. Dawb radical carbon sp2 hybrid, peb sp2 hybrid orbitals muaj ib daim duab peb sab qauv, txhua sp2 hybrid orbital thiab lwm yam atomic orbitals los ntawm axial overlap los ua ib tug σ daim ntawv cog lus, lub tsev cog khoom orbital muaj ib tug khub ntawm opposite spin electrons. Lub p orbital yog perpendicular rau lub dav hlau no, thiab p orbital yog nyob ntawm ib leeg electron.
2. Bond dissociation zog thiab carbon radical stability
(1) kev sib txuas lus sib zog
Cov atoms nyob rau hauv ib lub molecule yeej ib txwm ua me me vibrations nyob ib ncig ntawm lawv equilibrium txoj hauj lwm, molecular vibrations zoo ib yam li lub zog ntawm lub pob uas txuas nrog lub caij nplooj ntoos hlav, nyob rau hauv chav tsev kub, thaum lub molecules nyob rau hauv lub hauv av, lub amplitude yog me me, lub molecules. nqus zog, thiab amplitude nce. Yog tias lub zog txaus nqus tau, qhov amplitude nce mus rau qee qhov, cov nyiaj sib tsoo, thiab cov cua sov absorbed yog enthalpy (ΔH) ntawm daim ntawv cog lus dissociation cov tshuaj tiv thaiv, thiab daim ntawv cog lus zog, los yog daim ntawv cog lus-dissociation zog, yog qhia nyob rau hauv Ed.
(2) Kev ruaj ntseg ntawm carbon dawb radicals
Qhov kev ruaj ntseg ntawm cov radical hais txog kev ruaj ntseg ntawm nws cov niam txiv compound, uas yog ntau yam tsis ruaj khov dua li cov niam txiv compound, thiab tsis ruaj khov dua li cov niam txiv compound. Los ntawm cov ntaub ntawv saum toj no dissociation zog ntawm CH daim ntawv cog lus, nws pom tau hais tias lub zog dissociation ntawm CH daim ntawv cog lus nyob rau hauv CH4 yog qhov loj tshaj plaws, thiab cov thawj compound nyob rau hauv tib series yog feem ntau kuj tshwj xeeb; Lub zog hydrogen dissociation ntawm CH3CH3 thiab CH3CH2CH3 ntawm thawj cov pa roj carbon tsawg dua me ntsis ntawm CH4, thiab ob qho tib si ntawm lawv tsim thawj cov dawb radicals. Cov hydrogen nyob rau theem nrab carbon atom hauv CH3CH2CH3 muaj qis zog dissociation thiab tsim cov dawb radicals thib ob. Cov hydrogen ntawm tertiary carbon atom nyob rau hauv (CH3) 3CH so, uas muaj lub zog dissociation qis tshaj plaws thiab tsim cov tertiary dawb radical. Ib qho ntawm cov khoom lag luam ntawm cov kev sib raug zoo ntawm kev sib raug zoo yog tias lawv yog tib yam, yog li qhov sib txawv ntawm daim ntawv cog lus dissociation zog yog ib qho kev xav ntawm qhov sib txawv ntawm cov pa roj carbon radical. Qhov qis dua lub zog dissociation, qhov ruaj khov ntawm cov pa roj carbon radical. Yog li ntawd, kev ruaj ntseg kev txiav txim ntawm carbon radicals yog
3°C·>2°C·>1°C·>H3C·
Hauv alkanes, CC daim ntawv cog lus kuj tuaj yeem sib cais.