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Author Topic: Benzene phenol and cyclo hexane OH MY!!! ??WTF?  (Read 1786 times)

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bubblegumpi

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Benzene phenol and cyclo hexane OH MY!!! ??WTF?
« on: December 03, 2018, 01:28:01 AM »

I am struggling to figure this most useful and common group which is which and when is it called.

For example: 5,5-DIPHENYLHYDANTOIN; 57-41-0; Diphenylhydantoin; Dilantin Picture attached.


This is called diphenyl, so I see the six carbon rings with H:C in the 1:1 so its not cyclo hexane, but there are no OH groups that make benzene into phenol. Why is this not called dibenzene... ?

Also if you are looking at the diagram and you don't see the circle in the hexagon ring or the double bonds( = ) in three spots of the ring are they still there but just not illustrated?


As far as organic chemistry goes should we in proctise ignore cyclohexane C6H12 because its just not that common as a precursor or functional group or useful reagent to be used in the lab? Cyclohexane is found in gasoline and petro fuels but as I start my college education not worry about it too much, because while it looks like benzene its not? I like to try and figure out the names of things especially while looking at the shape of a drug vs. what it does to your body (another future college career path to me).


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mjc123

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Re: Benzene phenol and cyclo hexane OH MY!!! ??WTF?
« Reply #1 on: December 03, 2018, 02:03:31 AM »

The C6H5- group is called "phenyl". If there was an O, C6H5O- is called "phenoxy".
Just to confuse things, the C6H5CH2- group is called "benzyl".
That's how it is. You just have to learn these things.

If you see a hexagon without a circle or three double bonds, it is cyclohexane. (Non-chemists sometimes draw a benzene ring as simply a hexagon, but this is frowned on by chemists.)
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Borek

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Re: Benzene phenol and cyclo hexane OH MY!!! ??WTF?
« Reply #2 on: December 03, 2018, 06:00:06 AM »

Short version: don't expect too much logic in historical names that are still is use.
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bubblegumpi

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Re: Benzene phenol and cyclo hexane OH MY!!! ??WTF?
« Reply #3 on: December 03, 2018, 06:14:38 AM »

The C6H5- group is called "phenyl". If there was an O, C6H5O- is called "phenoxy".
Just to confuse things, the C6H5CH2- group is called "benzyl".
That's how it is. You just have to learn these things.

If you see a hexagon without a circle or three double bonds, it is cyclohexane. (Non-chemists sometimes draw a benzene ring as simply a hexagon, but this is frowned on by chemists.)
   

C6H5O does that have a ring with 6C and an O in the ring making a 7 member ring? Or do mean a 6C ring with a O attached to the 1' carbons with a double bond? Or do you mean one ring of a dioxin? (Dioxin is great for your face and complexon as that ukranian presidential candidate found out the hard way, if you are having trouble getting it for your tea, ask vlad putin or the KGB, trumps got him on speed dial)
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jeffmoonchop

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Re: Benzene phenol and cyclo hexane OH MY!!! ??WTF?
« Reply #4 on: December 03, 2018, 01:41:07 PM »

C6H5O- is a benzene ring with an O singly bonded to a carbon. There are no available bonds to form a double bond from a benzene ring, if there was it wouldn't be aromatic.

I'm not sure I've come across anyone drawing benzene without a ring in the centre or the 3 double bonds. I was taught that the frowned upon structure was drawing a ring inside the hexagon. Always draw the three double bonds. Anything without either the ring or double bonds is a cyclohexane.
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bubblegumpi

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Re: Benzene phenol and cyclo hexane OH MY!!! ??WTF?
« Reply #5 on: December 04, 2018, 12:57:19 AM »

C6H5O- is a benzene ring with an O singly bonded to a carbon. There are no available bonds to form a double bond from a benzene ring, if there was it wouldn't be aromatic.

I'm not sure I've come across anyone drawing benzene without a ring in the centre or the 3 double bonds. I was taught that the frowned upon structure was drawing a ring inside the hexagon. Always draw the three double bonds. Anything without either the ring or double bonds is a cyclohexane.


Which of these are you talking about?


Are some of these structures impossible like Fig 3 ? The resonant bonds always confuse me because it looks like the C only has three bonds. IS there "3.5" bonds with it always going between 3 and 4 in some sort of quantum state? I realize you can't have 3.5 bonds but mathematically in quantum physics would you have 3.5 bonds in benzene? 
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mjc123

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Re: Benzene phenol and cyclo hexane OH MY!!! ??WTF?
« Reply #6 on: December 04, 2018, 02:31:54 AM »

None of them is phenoxy. No.1 is phenoxy attached to an R group. (Phenoxy is a radical or substituent, not a molecule.) No.3 and 5 are impossible because you have 5 bonds to C and 3 bonds to O. 2 and 4 - count the atoms, see if you have C6H5O.
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jeffmoonchop

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Re: Benzene phenol and cyclo hexane OH MY!!! ??WTF?
« Reply #7 on: December 04, 2018, 01:22:07 PM »

A carbon will always have 4 bonds, normally we don't draw the bond to the hydrogens, so if you can see three bonds to a carbon, there will be another one to a hydrogen.
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bubblegumpi

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Re: Benzene phenol and cyclo hexane OH MY!!! ??WTF?
« Reply #8 on: January 12, 2019, 12:09:45 AM »

A carbon will always have 4 bonds, normally we don't draw the bond to the hydrogens, so if you can see three bonds to a carbon, there will be another one to a hydrogen.


That I do know I made to the 200 hundred series chem classes in college just been a while , I am trying to brush up before I go back to school.


Heres another ambiguous case of wording I get confused by:

Quote
Toluene (/ˈtɒljuiːn/), also known as toluol (/ˈtɒljuɒl/), is an aromatic hydrocarbon. It is a colorless, water-insoluble liquid with the smell associated with paint thinners. It is a mono-substituted benzene derivative, consisting of a CH3 group attached to a phenyl group. As such, its IUPAC systematic name is methylbenzene. Toluene is predominantly used as an industrial feedstock and a solvent. 


Why do they call it a phenol group when there is no -OH; its a benzene ring ring with a methyl? It didn't start as a phenol group either. Phenol is C6H6OH Toulene from benzene never has any O atom so I don't see why they would even mention phenol.


Also the buttons don't work for quote or subscripts or any for that matter above the text box. Is this a problem with edge or the forum?


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AWK

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Re: Benzene phenol and cyclo hexane OH MY!!! ??WTF?
« Reply #9 on: January 12, 2019, 12:40:15 AM »



Why do they call it a phenol group when there is no -OH; its a benzene ring ring with a methyl? It didn't start as a phenol group either. Phenol is C6H6OH Toulene from benzene never has any O atom so I don't see why they would even mention phenol.


Also the buttons don't work for quote or subscripts or any for that matter above the text box. Is this a problem with edge or the forum?
Phenyl does not mean pheno.

All buttons work correctly, problems may come from your side.
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bubblegumpi

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Re: Benzene phenol and cyclo hexane OH MY!!! ??WTF?
« Reply #10 on: January 12, 2019, 10:22:13 AM »



Why do they call it a phenol group when there is no -OH; its a benzene ring ring with a methyl? It didn't start as a phenol group either. Phenol is C6H6OH Toulene from benzene never has any O atom so I don't see why they would even mention phenol.


Also the buttons don't work for quote or subscripts or any for that matter above the text box. Is this a problem with edge or the forum?
Phenyl does not mean pheno.

All buttons work correctly, problems may come from your side.


Am I just typing wrong what is the difference?
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Re: Benzene phenol and cyclo hexane OH MY!!! ??WTF?
« Reply #11 on: January 12, 2019, 11:29:14 AM »

Phenyl is a group of atoms (C6H5) obtained by removing 1 hydrogen atom from benzene (C6H6)
Phenol (C6H5-OH)is a compound obtained by joining phenyl group with OH group.
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bubblegumpi

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Re: Benzene phenol and cyclo hexane OH MY!!! ??WTF?
« Reply #12 on: January 18, 2019, 02:01:58 AM »

That always was confusing me. So what is benzyl like in: alky-dimethyl-'benzyl'-ammonium-chloride? I could be spelling or not remembering the name correctly.


I always though benyl alcohol was phenol: a 6c ring with one H substituted with an OH group.
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mjc123

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Re: Benzene phenol and cyclo hexane OH MY!!! ??WTF?
« Reply #13 on: January 18, 2019, 02:13:25 AM »

I told you above, benzyl is C6H5-CH2-
Benzyl alcohol is C6H5-CH2OH
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