IUPAC Names for Chlorinated Methylbenzenes: Analysis & Solutions

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In summary: The question asked by @sjb-2812 was about preferred IUPAC names.And as far as the aptitude of the OP and, in general, homework assignments are concerned, only the 'preferred IUPAC name' is really of interest.The 'preferred IUPAC name' is the only thing of interest.
  • #1

Krushnaraj Pandya

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Homework Statement


among these, which are acceptable IUPAC names,
1-chloro-4-methylbenzene
4-chlorotoluene
4-methylchlorobenzene
1-methyl-4-chlorobenzene

2. The attempt at a solution
1)First option seems correct but is chlorine a higher priority group than methyl?? or does chlorine get a lower number due to alphabetical order?
2)toluene is accepted by IUPAC so correct
3)I see no reason as to why this should be incorrect
4)if methyl has higher priority then correct, if there is no such priority and alphabetical arrangement is followed in this case then incorrect- besides doesn't the name chlorobenzene imply chlorine is at position 1?

I'd be very grateful for some insight
 
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  • #2
Krushnaraj Pandya said:

Homework Statement


among these, which are acceptable IUPAC names,
1-chloro-4-methylbenzene
4-chlorotoluene
4-methylchlorobenzene
1-methyl-4-chlorobenzene

2. The attempt at a solution
1)First option seems correct but is chlorine a higher priority group than methyl?? or does chlorine get a lower number due to alphabetical order?
2)toluene is accepted by IUPAC so correct
3)I see no reason as to why this should be incorrect
4)if methyl has higher priority then correct, if there is no such priority and alphabetical arrangement is followed in this case then incorrect- besides doesn't the name chlorobenzene imply chlorine is at position 1?

I'd be very grateful for some insight
1st is absolutely correct
2nd one is correct and accepted by IUPAC but it is a common name and is not IUPAC nomenclature.
3rd is correct
4th is incorrect because alphabet is given priority.
 
  • #3
Victim said:
1st is absolutely correct
2nd one is correct and accepted by IUPAC but it is a common name and is not IUPAC nomenclature.
3rd is correct
4th is incorrect because alphabet is given priority.
I thought so, but here's the twist. 3rd is incorrect, I can't figure out how
 
  • #4
Krushnaraj Pandya said:
I thought so, but here's the twist. 3rd is incorrect, I can't figure out how
Krushnaraj Pandya said:
I thought so, but here's the twist. 3rd is incorrect, I can't figure out how
4th is incorrect.The alkyl group is given least priority.
 
  • #5
Victim said:
4th is incorrect.The alkyl group is given least priority.
you're right. 4th is incorrect and I understand that, but 3rd is incorrect too- why is that?
 
  • #6
Victim said:
4th is incorrect.The alkyl group is given least priority.
even though chlorobenzene is accepted by IUPAC
 
  • #7
Krushnaraj Pandya said:
even though chlorobenzene is accepted by IUPAC
yes chlorobenzene is accepted but 1methyl 4 chloro benzene is not accepted
 
  • #8
Victim said:
yes chlorobenzene is accepted but 1methyl 4 chloro benzene is not accepted
I got that. My problem is regarding 4-methyl chlorobenzene now
 
  • #12
3rd is incorrect because, by definition, the "parent chain" must be a pure hydrocarbon, and chlorobenzene isn't one.
 
  • #13
baldbrain said:
3rd is incorrect because, by definition, the "parent chain" must be a pure hydrocarbon, and chlorobenzene isn't one.
any link for reference to this rule??
 
  • #14
Krushnaraj Pandya said:
any link for reference to this rule??
I can give you one, but these are the very basics. If the parent hydrocarbon would compose something other than only C & H, there would remain no basis for classification.
 
  • #16
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  • #17
baldbrain said:
Tell me, what is the 'parent chain' or stem of the name 2-chloropropanol?

Just because it is propane doesn't make your earlier statement correct (perhaps it is, I don't know for sure).

If memory serves me well (won't be the first time it fails if I am wrong) IUPAC rules allow usage of non-systematic common names as long as the result is unambiguous. so chances are it all depends on how orthodox you want to be about naming.
 
  • #18
baldbrain said:
This is absolutely correct. The '-oic acid' is a suffix (grammatically they would be 2 words, but relate it similar to -ol, -one, -amine etc. or any other suffix). The stem of this name is still toluene.
Tell me, what is the 'parent chain' or stem of the name 2-chloropropanol?
Edit: The stem of this name is still toluene.
 
  • #19
Borek said:
If memory serves me well (won't be the first time it fails if I am wrong) IUPAC rules allow usage of non-systematic common names as long as the result is unambiguous. so chances are it all depends on how orthodox you want to be about naming.
The question asked by @sjb-2812 was about preferred IUPAC names.
And as far as the aptitude of the OP and, in general, homework assignments are concerned, only the 'preferred IUPAC name' is really of interest.
Borek said:
Just because it is propane doesn't make your earlier statement correct (perhaps it is, I don't know for sure).
I gave them something easy to start with.
And as far as I know, it is correct. Look up any compound's 'preferred IUPAC name' on Wikipedia (I know it Wikipedia isn't fully reliable, nothing is, for that matter) and you'll find the 'parent chain' to be a pure hydrocarbon.
Do tell me if you find a compound that violates this rule.
 
  • #20
If you're thinking biomacromolecules, I agree that their rigorous IUPAC names are unnecessary.
 

1. What is the purpose of using IUPAC names for chlorinated methylbenzenes?

The International Union of Pure and Applied Chemistry (IUPAC) names for chlorinated methylbenzenes provide a standardized and systematic way of naming these chemical compounds. This allows for clear communication and understanding among scientists and helps to avoid confusion or errors in the identification of these compounds.

2. How are IUPAC names for chlorinated methylbenzenes determined?

IUPAC names for chlorinated methylbenzenes are based on a set of rules and guidelines outlined by the IUPAC nomenclature system. These rules take into account the molecular structure and functional groups present in the compound to assign a unique and systematic name.

3. What are the common challenges in analyzing and naming chlorinated methylbenzenes?

One of the main challenges in analyzing and naming chlorinated methylbenzenes is the presence of multiple chlorine atoms at different positions on the benzene ring. This can result in a variety of isomers with different physical and chemical properties. Another challenge is the potential for ring substitution or rearrangement reactions to occur, leading to even more complex structures.

4. What solutions are available for addressing these challenges?

To address the challenges in analyzing and naming chlorinated methylbenzenes, it is important to use advanced analytical techniques such as gas chromatography-mass spectrometry (GC-MS) or nuclear magnetic resonance (NMR) spectroscopy. These techniques can help to accurately identify the structure and position of chlorine atoms on the benzene ring. Additionally, the IUPAC nomenclature system provides specific rules for handling complex structures and naming isomers.

5. Are there any safety considerations when working with chlorinated methylbenzenes?

Yes, there are some safety considerations when working with chlorinated methylbenzenes, as they are toxic and can pose health hazards if not handled properly. It is important to follow proper safety protocols and use appropriate protective equipment when handling these compounds. It is also recommended to have a thorough understanding of their properties and potential risks before working with them in a laboratory setting.

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