What happens in a nitration reaction?
Nitration happens when one (or more) of the hydrogen atoms on the benzene ring is replaced by a nitro group, NO2. Benzene is treated with a mixture of concentrated nitric acid and concentrated sulfuric acid at a temperature not exceeding 50°C. The mixture is held at this temperature for about half an hour.
What are the factors affecting nitration?
The temperature affects the below factors in aromatic nitrations. Kinetic rate constant for various chemical steps increases with the temperature. Solubilities present in the acid phase of both the nitrated and uninitiated aromatics increase with temperature probably.
Is nitration a chemical reaction?
The nitration process is a general class of chemical process for the introduction of a nitro group (NO2) into an organic chemical compound.
Are nitration reactions exothermic?
In general, nitration reactions are fast and highly exothermic. A large proportion of nitric acid consumed during aromatic nitration is directed towards the synthesis of aniline derivatives, which are produced by nitration followed by reduction.
What is the purpose of nitration reaction?
Nitration is used to add nitrogen to a benzene ring, which can be used further in substitution reactions. The nitro group acts as a ring deactivator. Having nitrogen present in a ring is very useful because it can be used as a directing group as well as a masked amino group.
What is the final product of nitration?
Hence, toluene undergoes nitration to give ortho and para nitro toluene isomers, but when heated it can give dinitrotoluene and ultimately the explosive trinitrotoluene.
How does nitric acid behave in nitration?
Nitric acid reacts with proteins to form yellow nitrated products. This reaction is known as the xanthoproteic reaction. This test is carried out by adding concentrated nitric acid to the substance being tested, and then heating the mixture.
Why is nitration done at low temperatures?
Nitro groups “direct” new groups into the 3 and 5 positions. The reasons for this “directing effect” is due to decativating nature of nitro group. At higher temperatures there is a greater chance of getting more than one nitro group substituted onto the ring.
What is the effect of water on the nitration reaction?
Concentrated sulfuric acid is the solvent for this reaction and is involved in the formation of nitronium ion from concentrated nitric acid. Water has a retarding effect on the nitration since it interferes with the nitric acid-sulfuric acid equilibrium (shown below) that generates the required nitronium ion.
Why nitration is exothermic reaction?
Why is nitration exothermic? The reaction of acids produces nitrate ion (NO2-) which will attach to the benzene ring. This reaction is extremely exothermic, which means it produces a significant amount of heat energy. For this reason, the acid mixture is added very slowly and the reaction is kept in an ice bath.
What product will be in the process of nitration?
When nitric acid is used as the nitrating agent for propane, only 35-40% of the nitric acid reacts to form nitroparaffins. In this case, l-nitropropane, 2- nitropropane, nitroethane, and nitromethane are all produced. Oxygenated products include aldehydes, alcohols, and CO.
Which metal does not react with nitric acid?
Some precious metals, such as pure gold and platinum-group metals do not react with nitric acid, though pure gold does react with aqua regia, a mixture of concentrated nitric acid and hydrochloric acid.