Is chlorination or bromination more selective?

Is chlorination or bromination more selective?

A chain reaction mechanism for the chlorination of methane has been described. Bromination of alkanes occurs by a similar mechanism, but is slower and more selective because a bromine atom is a less reactive hydrogen abstraction agent than a chlorine atom, as reflected by the higher bond energy of H-Cl than H-Br.

Which is faster bromination or chlorination?

Chlorination is faster than bromination because chlorine is more reactive.

Why chlorine is reactive but not selective?

Chlorination is less selective than bromination because chlorination has smaller differences in activation energy for attack at 1°, 2°, and 3° positions. Consider the halogenation of propane at the 1° and 2° positions. The rates depend on the activation energies.

Is radical chlorination selective?

Radical halogenation is selective for the most substituted C-H. Two electrons decrease in energy, one electron increases in energy Stability trend for R3C•: one electron increases in energy.

Why is chlorination more reactive than bromination?

Although the bromine nucleus is more positively charged than the chlorine nucleus, the increase in the radius and the extra shielding in the bromine atom outweigh this factor, which means that an electron is more easily attracted into the outer shell of a chlorine atom than that of a bromine atom, so chlorine is more …

What is the chlorination of methane?

If a mixture of methane and chlorine is exposed to a flame, it explodes – producing carbon and hydrogen chloride. This is not a very useful reaction! The reaction we are going to explore is a more gentle one between methane and chlorine in the presence of ultraviolet light – typically sunlight.

What are the two main difference between chlorination and bromination?

We’ll do the math in a second, but the key difference is that in chlorination, the key propagation step is exothermic and in bromination, the key propagation step is endothermic. This is because chlorination forms a strong H-Cl bond (103 kcal/mol) and bromination forms a much weaker H-Br bond (87 kcal/mol).

What is selectivity in halogenation?

How To Quantify “Selectivity” In Free Radical Chlorination. This deviation from a statistical mixture is referred to as selectivity. So for this reaction, the free radical chlorination of propane at 25°C, chlorine is 3.66 times more selective for secondary hydrogens than for primary hydrogens.

Is bromine more reactive than chlorine?

Because chlorine is more reactive than bromine, it displaces bromine from sodium bromide. The solution turns brown.

Why is bromine less reactive than chlorine?

Because a bromine atom has one more full shell than a chlorine atom, it has more shielding which means the attraction between the nucleus and an electron is weaker.

Which element is most selective in its halogenation?

Bromine radical is less reactive and more selective. In contrast, chlorine radical is more reactive and less selective in its reaction.

What is the major product of chlorination of methane?

Thus the final product of chlorination of methane in the sunlight is carbon tetrachloride, i.e. option D is the correct answer. Note: The chlorination of methane also takes place in thermal conditions. If the amount of chlorine is limited then the major product is methyl chloride i.e. \[C{H_3}Cl\].

Why is chlorination less selective than bromination?

Chlorination is less selective than bromination because chlorination has smaller differences in activation energy for attack at 1°, 2°, and 3° positions.

Why is chlorination faster than bromination?

Comparison of rate of reaction in bromination and chlorination. I did research, about this one but the data and other things prove chlorination is faster than bromination, because chlorine is more reactive. But, some data says reaction of chlorine is more exothermic then bromine, that is the reason.

Which is better chlorine or bromine?

Chlorine and bromine: what’s the difference? Chemical changes. The first difference is in the way that the two sanitisers work chemically. Speed of use. Another difference is in the speed that each chemical cleans your pool. Warming up. Bromine tolerates heat much better than chlorine does. Health benefits.

Is bromine better than chlorine?

BCDMH, on the other hand, is self-activating because it contains some chlorine. Bromine works better in hotter water and decreased water volumes than chlorine, but because it is sensitive to sunlight and can deteriorate, it is not used in pools.