What is radical halogenation?

Radical halogenation (free radical halogenation): A substitution reaction in which a hydrogen atom is replaced with a halogen atom, via a free radical reaction mechanism.

What is the first step in radical halogenation of alkanes?

In the first propagation step, a chlorine radical combines with a hydrogen on the methane. This gives hydrochloric acid (HCl, the inorganic product of this reaction) and the methyl radical.

Where does radical halogenation happen?

Free radical halogenation is a reaction that substitutes a chlorine or a bromine for a hydrogen on an alkane. This reaction is a photochemical one. That is, it occurs only when performed in the presence of uv light (abbreviated hv).

What does NBS do to a double bond?

NBS As A Reagent For Allylic Bromination NBS is used as a substitute for Br2 in these cases since Br2 tends to react with double bonds to form dibromides. The advantage of NBS is that it provides a low-level concentration of Br2, and bromination of the double bond doesn’t compete as much.

How does an alkane react with a halogen?

Alkanes: Halogenation. The reaction of a halogen with an alkane in the presence of ultraviolet (UV) light or heat leads to the formation of a haloalkane (alkyl halide). An example is the chlorination of methane. Experiments have shown that when the alkane and halogen reactants are not exposed to UV light or heat, the reaction does not occur.

How does an alkene react with HBr?

Alkenes react with hydrogen bromide in the cold. The double bond breaks and a hydrogen atom ends up attached to one of the carbons and a bromine atom to the other. In the case of ethene, bromoethane is formed. (1) CH 2 = CH 2 + HBr → CH 3 CH 2 Br. With cyclohexene you get bromocyclohexane.

What is the general structure of an alkene?

Overview of Alkene- Structure When there is one double bond between two C atoms, there are two H atoms less than alkanes. Therefore, the general formula for an alkene is CnH2n. Alkenes are also known as olefins, which are oily liquids because of the first member; ethene forms an oily liquid on reaction with chlorine.

What are the common reactions of alkenes?

Catalytic Hydrogenation of Alkenes.