Polarity of large CHO compunds

[paraflax]

Hello!
Does anyone have information or knowledge on the polarity of larger CxHyOz compunds?
To be more specific, the compunds that I'm interested in are different kinds of lignans such as Hydroxymatarésinol (C20H22O7) and tannins such as taxifoline (C15H12O7) just to name a few.

As I understand it, compunds with -OH groups tend to be polar so I want to say that they are polar, but I'm wondering if the size of the compunds and/or the positions of the OH-groups have any influence on the overall polarity?

It's for a report want to be able to back up my claims of polarity or non-polarity with more than just the -OH groups argument =)

Any help will be greatly appreciated =)

 

[Borek]

I'm wondering if the size of the compunds and/or the positions of the OH-groups have any influence on the overall polarity?

Yes & yes.

 

[paraflax]

As I thought, would you mind explaining it a bit more if you can?

 

[Borek]

Sorry, I can't.

Don't get me wrong - it is not that I don't want to help, but the topic itself is worth a thick book.

In general if the -OH groups are at the "outside" of the molecule, and if they are more acidic than typical alcohol groups, you can expect the molecule to be more polar. But it is just scratching of the surface.

 

[paraflax]

I was afraid of that, but thanks anyway. I'll keep looking.