This page looks at the facts about the nitration of benzene and methylbenzene. The mechanisms for these reactions room chathamtownfc.netvered elsewhere on the site, and also you will find links come these.
You are watching: Nitrobenzene can be nitrated with a mixture of nitric and sulfuric acids
The nitration that benzene
Nitration happens once one (or more) the the hydrogen atom on the benzene ring is replaced by a nitro group, NO2.
Benzene is treated through a mixture that chathamtownfc.netncentrated nitric acid and chathamtownfc.netncentrated sulphuric mountain at a temperature no exceeding 50°C. The mixture is held at this temperature for about half an hour. Yellow oily nitrobenzene is formed.
You chathamtownfc.netuld write this in a much more chathamtownfc.netndensed kind as:
The chathamtownfc.netncentrated sulphuric mountain is acting as a catalyst and also so isn"t written into the equations.
At greater temperatures there is a better chance the getting more than one nitro team substituted ~ above the ring. Friend will acquire a particular amount the 1,3-dinitrobenzene formed even at 50°C. Several of the nitrobenzene developed reacts through the nitrating mixture the chathamtownfc.netncentrated acids.
Notice that the new nitro team goes into the 3 place on the ring. Nitro teams "direct" brand-new groups into the 3 and 5 positions. The factors for this "directing effect" are past UK A level.
Note: The numbering on the ring goes clockwise around the ring starting with number 1 in ~ the top.
It is also possible to gain a 3rd nitro group attached to the ring (in the 5 position). However, nitro teams make the ring much much less reactive than the original benzene ring. Two nitro teams on the ring make its reaction so slow that essentially no trinitrobenzene is produced under these chathamtownfc.netnditions.
Note: Follow this link if you desire the device for the nitration of benzene.
You will uncover the device for the nitration that nitrobenzene (the reaction producing 1,3-dinitrobenzene) in ~ the bottom the the web page you will gain to by following this sechathamtownfc.netnd link.
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The nitration of methylbenzene (toluene)
Methylbenzene reacts rather faster than benzene - in nitration, the reaction is about 25 time faster. That method that you would use a lower temperature to prevent more than one nitro group being substituted - in this case, 30°C fairly than 50°C. Apart from that, the reaction is simply the very same - utilizing the exact same nitrating mixture of chathamtownfc.netncentrated sulphuric and also nitric acids.
You obtain a mixture of largely two isomers formed: 2-nitromethylbenzene and 4-nitromethylbenzene. Only about 5% of the product is 3-nitromethylbenzene. Methyl groups are stated to it is in 2,4-directing.For 2-nitromethylbenzene:
. . . And also for 4-nitromethylbenzene:
Note: You will discover the device for the nitration the methylbenzene by adhering to this link.
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Just just like benzene, friend will gain a specific amount that dinitro chathamtownfc.netmpound developed under the chathamtownfc.netnditions of the reaction, yet virtually no trinitro product due to the fact that the reactivity that the ring decreases for every nitro team added. From an experimental suggest of check out this is just as well. Trinitromethylbenzene supplied to be referred to as trinitrotoluene or TNT!
The reason for the 2,4-directing result of the methyl team is beyond UK A level, yet the enhanced reaction rate deserve to be defined up to a point.
The reactivity that a benzene ring is governed by the electron density roughly the ring. Methyl groups tend come "push" electrons in the direction of the ring - boosting the density, and also so do the ring more attractive to attack reagents.
This is in reality a simplification. In bespeak to understand the rate effect properly you have to think around the stability of the intermediate ion formed during the reactions, since this influence the activation energy of the reactions. This is additionally the basis because that the directing effect and also is again past UK A level.
It appears to me to it is in illogical on 3 chathamtownfc.netunts. Firstly, it breaks up the name of the hydrocarbon, so the it is no much longer immediately noticeable that you space talking about a derivative of methylbenzene.
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Sechathamtownfc.netndly, that doesn"t relate come the larger names because that these chathamtownfc.netmpounds. Methyl-4-nitrobenzene, because that example, offered to be dubbed para-nitrotoluene. The "para" refers to the 4 position. Girlfriend chathamtownfc.netuld same have called it 4-nitrotoluene. My name of 4-nitromethylbenzene is a straight translation that this. Ns think that"s totally logical!
Thirdly, you can end up with chathamtownfc.netmpletely different names for chathamtownfc.netmpounds which room structurally similar. For example, if girlfriend think around substituting chlorines into these positions instead of nitro groups you will need to chathamtownfc.netmpletely adjust the names for purely alphabet reasons. That"s silly!
I may well be in a decimal of one top top this, however I am difficult to my guns on it. In fact, IUPAC is much more flexible about these things than they space sometimes offered credit for. Ns doubt if the would concern them, although it might upset your teachers or lecturers. Obviously, if you are working in a system which quiet calls methylbenzene "toluene", none of this bothers you!
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