RADICAL SUBSTITUTION(pentane and bromine) Flashcards
what is needed for halogenation of alkanes
UV LIGHT/SUNLIGHT
Initiation:
A halogen molecule (e.g., Cl2, Br2) is broken down into two radicals by UV light or heat, forming two halogen radicals (e.g., Cl, Br).
VIA HOMOLYTIC FISSION
initiation of bromine
br-br-> WITH UV, br. + br.
propagation
radicals on both sides of the equation
chain reaction
2 steps
propagation example
step1: c5h12+br. ->.c5h11 + hbr
step 2: .c5h11 + br2 ->c5h11br +br.
propagation general
step1: alkane +halogen radical->alkyl radical +halogen halide
step2:alkyl radical+ original halogen->haloalkane +halogen radical
propagation overall
alkane + halogen molecule-> haloalkane + hydrogen halide
propagation overall example
c5h12+br2->c5h11br+hbr
termination
two radicals collide, forming a molecule with all electrons paired
termination general
halogen radicals-> halogen
alkyl radical + halogen radical->haloalkane
alkyl radicals->alkane
termination example
br. +br. ->br2
.c5h11 +br.->c5h11br
.c5h11+.c5h11->c10h22
overall formula for halogenation
alkane+ halogen->haloalkane + hydrogen halide gas
homolytic fission
breaking of a covalent bond where each atom involved in the bond receives one of the shared electrons, resulting in the formation of two radicals.
radical substitution is
a reaction where a hydrogen atom in an alkane is replaced by a halogen atom (like chlorine or bromine)
steps of radical substitution
, involving initiation, propagation, and termination steps.
radical
a very reactive species, atom or group of atoms with unpaired electrons
what does heterolytic fission form
ions
how do you represent homo vs heterolytic fission
homo-fishhook, one electron to each
hetero-curly arrow, 2e- to one atom
