What does NBS do to toluene?

Toluene (1) undergoes benzylic bromination when heated with N-bromosuccinimide (NBS, 2). Before toluene (1) reacts though, NBS (2) generates both bromine radicals (Br•) and diatomic bromine (Br2).

Why we use NBS instead of Br2?

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.

What is the purpose of using NBS in a radical reaction?

In the Goldfinger mechanism, the purpose of the NBS is simply to maintain a very low concentration of molecular bromine, while in the Bloomfield mechanism, its purpose is the generation of the initial radical used in the reaction, which again can be quite a difficult process.

What is the purpose of NBS?

N-Bromosuccinimide or NBS is a chemical reagent used in radical substitution, electrophilic addition, and electrophilic substitution reactions in organic chemistry. NBS can be a convenient source of Br•, the bromine radical.

What is benzylic bromination?

Allylic and benzylic bromination refer to the substituion of a bromine for a hydrogen on an allylic carbon (a carbon atom 1 bond from an alkene) or on a benzylic carbon (a carbon atom 1 bond from a benzene). These two reactions are carried out using N-bromosuccinimide (abbreviated NBS).

What is the role of NBS in allylic bromination?

NBS (N-bromosuccinimide) is the most commonly used reagent to produce low concentrations of bromine. When suspended in tetrachloride (CCl4), NBS reacts with trace amounts of HBr to produce a low enough concentration of bromine to facilitate the allylic bromination reaction.

Who uses NBS?

The NBS platform is used by organisations of all sizes from small architecture and engineering firms, to the very largest global construction companies.

Does toluene react with bromine?

Benzene and toluene do not react with bromine in the absence of a catalyst. Phenol is more reactive due to the presence of an electron donating hydroxyl group and reacts with bromine by a substitution reaction forming hydrogen bromide gas.

What is the purpose of bromine test?

In organic chemistry, the bromine test is a qualitative test for the presence of unsaturation (carbon-to-carbon double or triple bonds), phenols and anilines.

What happens when N-bromosuccinimide is heated with toluene?

Toluene (1) undergoes benzylic bromination when heated with N-bromosuccinimide (NBS, 2). Before toluene (1) reacts though, NBS (2) generates both bromine radicals (Br•) and diatomic bromine (Br. 2). First, draw the product of this reaction.

What is the difference between aromatic bromination and nitration of toluene?

Both bromination reactions occur with a different mechanism. Generally, side chain by free radical mechanism and aromatic bromination follows electrophilic substitution mechanism. Introduction of a nitro group into toluene forms ortho-toluene & para-toluene and the reaction is called as nitration of toluene.

Why does toluene undergo electrophilic aromatic substitution?

Reactions of Toluene are similar to the reactions of normal aromatic hydrocarbon in electrophilic aromatic substitution. The reason behind this is because the methyl group present in toluene has greater electron-releasing properties than hydrogen atom present in the same position.

What is nitration of toluene and how does it work?

Introduction of a nitro group into toluene forms ortho-toluene & para-toluene and the reaction is called as nitration of toluene. The reaction follows the electrophilic substitution mechanism, and the mixture of concentrated sulfuric and nitric acid behaves as a nitrating agent.