How can a ring compound be saturated or unsaturated?

[HdK]

What does it mean for a ring to be saturated or unsaturated? I can't imagine it having the same definition as any hydrocarbon. can someone explain? For example, pyrrole is unsaturated. Is it the same meaning as any hydrocarbon? So it has double bond in the ring so its unsaturated?

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[hope_to_match]

Well you have to use the formula C👎H(2n+2) and for every structure in order to figure out the degrees of unsaturation. Also, when you do the math: oxygens can be ignored, halogens count as +1 hydrogen and nitrogens as 1/2 carbon.

 

[Koalafied]

What does it mean for a ring to be saturated or unsaturated?

http://en.wikipedia.org/wiki/Saturated_and_unsaturated_compounds

I can't imagine it having the same definition as any hydrocarbon.

http://en.wikipedia.org/wiki/Saturated_and_unsaturated_compounds

can someone explain?

http://en.wikipedia.org/wiki/Saturated_and_unsaturated_compounds

For example, pyrrole is unsaturated.

That is correct.

Is it the same meaning as any hydrocarbon?

http://en.wikipedia.org/wiki/Saturated_and_unsaturated_compounds

So it has double bond in the ring so its unsaturated?

In that particular case, yes.

Moving on......

Important equation: [2(C) + 2 – (H)] ÷ 2 = degrees of unsaturation
1 Carbon = 1 C
1 Nitrogen = ½ C
1 Hydrogen = 1 H
1 Halogen = 1 H
1 Oxygen = 0 H

1 double bond = 1 degree
1 triple bond = 2 degrees
1 ring = 1 degree
(e.g. Touluene = 4 degrees b/c 1 ring + 3 double bonds = 4 degrees)

Can you figure out pyrrole's degree(s), OP?
Can you tell the difference between unsaturated fats and saturated fats, OP?

 

[FeralisExtremum]

Well you have to use the formula C👎H(2n+2) and for every structure in order to figure out the degrees of unsaturation. Also, when you do the math: oxygens can be ignored, halogens count as +1 hydrogen and nitrogens as 1/2 carbon.

Agreed, use this formula. Also don't forget that you lose a degree of saturation for any double bonds present, and any rings. So if you have a ring, you lose a degree of saturation (2 H's). If you have a double bond, you lose a degree of saturation (2 H's per double bond). If you have a triple bond, you count that as two double bonds (4 H's).

So let's look at pyrrole:

We have 4 carbons, and 1 Nitrogen. Using the formula, that means we need 11 Hydrogens for full saturation (remember that since there is an N present, we add an additional H for full saturation). However, we have two double bonds AND a ring, which means we've lost 3 degrees of saturation (or 6 H's), leaving us with only 5 H's in our final structure.

This matches with the image. As you can see this structure is unsaturated, as it is far short of the 11 H's it would need to be considered fully saturated.

 

[hope_to_match]

Agreed, use this formula. Also don't forget that you lose a degree of saturation for any double bonds present, and any rings. So if you have a ring, you lose a degree of saturation (2 H's). If you have a double bond, you lose a degree of saturation (2 H's per double bond). If you have a triple bond, you count that as two double bonds (4 H's).

👍 thanks for adding to what i said!

 

[Koalafied]

😉

http://www.personal.psu.edu/the1/unsatura.htm
http://firstyear.chem.usyd.edu.au/calculators/degree_of_unsaturation.shtml.

 

[hope_to_match]

😉

http://www.personal.psu.edu/the1/unsatura.htm
http://firstyear.chem.usyd.edu.au/calculators/degree_of_unsaturation.shtml

haha you always post links to everyone's questions

 

[HdK]

Thank you everyone!