How do I know what the IUPAC name is of arenes?
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How do I know what the IUPAC name is of arenes?in an exam if I am asked to name an arene
it could be:
ethyl benzene or phenyl ethane.
Both are correct but examiners may be picky and demand one and not the other.
I think the safest option is to use IUPAC.
BUT when do I use phenyl- and when do I use -benzene (e.g: phenyl amine or chlorobenzene)??
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Re: How do I know what the IUPAC name is of arenes?Use phenyl when it can be treated as a side-chain, use benzene when it can be treated as a functional group.
If you can't decide which, use benzene as it's often easier to integrate. -
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Re: How do I know what the IUPAC name is of arenes?what do you mean use phneyl when it can be reated as a side-chain(Original post by dmccririck)
Use phenyl when it can be treated as a side-chain, use benzene when it can be treated as a functional group.
If you can't decide which, use benzene as it's often easier to integrate.
surely in phenyl amine the AMINE group is a side chain NOT phenyl?? -
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Re: How do I know what the IUPAC name is of arenes?The amine will be the functional group, as it's the most reactive bit... the benzene ring won't take part in the reaction so is treated as a side-chain.(Original post by ilovemath)
what do you mean use phneyl when it can be reated as a side-chain
surely in phenyl amine the AMINE group is a side chain NOT phenyl?? -
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Re: How do I know what the IUPAC name is of arenes?but in benzoic acid, the acid takes part so it should be pheyl methanoic acid? but it is not(Original post by dmccririck)
The amine will be the functional group, as it's the most reactive bit... the benzene ring won't take part in the reaction so is treated as a side-chain.
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Re: How do I know what the IUPAC name is of arenes?Hmmm okay, let me change my answer:(Original post by ilovemath)
but in benzoic acid, the acid takes part so it should be pheyl methanoic acid? but it is not
Use phenyl when the benzene is a substituent to another carbon chain.
Use benzene if other substituents like -F, -Cl, -CH3, -OH are bonded to the benzene ring. -
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Re: How do I know what the IUPAC name is of arenes?see this is why it is confusing(Original post by dmccririck)
Hmmm okay, let me change my answer:
Use phenyl when the benzene is a substituent to another carbon chain.
Use benzene if other substituents like -F, -Cl, -CH3, -OH are bonded to the benzene ring.
-NH2 is a substituent but it is phenyl amine??? -
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Re: How do I know what the IUPAC name is of arenes?It's all to do with priority. Groups with priority get the suffix.(Original post by ilovemath)
see this is why it is confusing
-NH2 is a substituent but it is phenyl amine???
Amines have a greater priority, so they get the suffix. Out of amines and benzene rings, benzene rings have less priority, so they get the prefix, phenyl-.
Hence, it's phenylamine.
According to IUPAC, calling it aminobenzene is wrong.
However, halogens have less priority than benzene rings, so they get the prefix, and benzene rings get the suffix, -benzene.
Hence, C6H5Cl = chlorobenzene. -
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Re: How do I know what the IUPAC name is of arenes?do you have a priority table / list?(Original post by thegodofgod)
It's all to do with priority. Groups with priority get the suffix.
Amines have a greater priority, so they get the suffix. Out of amines and benzene rings, benzene rings have less priority, so they get the prefix, phenyl-.
Hence, it's phenylamine.
According to IUPAC, calling it aminobenzene is wrong.
However, halogens have less priority than benzene rings, so they get the prefix, and benzene rings get the suffix, -benzene.
Hence, C6H5Cl = chlorobenzene. -
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Re: How do I know what the IUPAC name is of arenes?ok well if exam boards favour systematic they are likely to accept more than one alternative(Original post by EierVonSatan)
Welcome to the minefield that is nomenclature
There is a difference between IUPAC accepted names and systematic names (which A-level exam boards tend to favour, as it's methodical).
e.g: aminobenzene and phenyl amine, right? -
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Re: How do I know what the IUPAC name is of arenes?I'd have thought so but you should check. Just don't call it aniline(Original post by ilovemath)
ok well if exam boards favour systematic they are likely to accept more than one alternative
e.g: aminobenzene and phenyl amine, right?
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Re: How do I know what the IUPAC name is of arenes?I would guess so, don't take my word for it though(Original post by ilovemath)
ok well if exam boards favour systematic they are likely to accept more than one alternative
e.g: aminobenzene and phenyl amine, right?
There is enough complexity in nomenclature to baffle most examiners, so they'd make it so that it's not too strict
To see some of this complexity, see this 'simple' chart to naming TNT.
Spoiler:Show
