I'm sure this is simple enough but for some reason my brain is not willing to work with me!

 

Theobromine (a structural analogue of caffeine) dissolves easily in acids and bases, but is poorly soluble in water.

 

Why is that??

 

Thanks for any advice offered:)

Ah, the 'food of gods'! I don't really know the answer, but probably because water is incapable of breaking the bonds that exist between the atoms of theobromine. Just a guess!

 

BTW, Wiki says theobromine is water insoluble

Erm, first of all NEVER use wikipedia, it's a pile of poo! And monkeys probably write half the stuff on there;)

 

Second, it is classed as poorly water soluble, this is because it takes around 2000ml of water to dissolve 1g of Theobromine. It's called water-insoluble 'cos that's far above the amount it would require if it were water-soluble, however it's not technically 'insoluble'.

 

Thanks for the response tho,

I reckon it is something to do with pH...

My best guess is that it forms salts with acids and bases. The salts are more polar than the original molecule and are more water soluble.

 

BTW, if you think Wiki's wrong then why not correct it?

Solubility: Very slightly soluble in cold water.

 

taken from: http://64.233.183.104/search?q=cache:4gsYRaViqgcJ:www.sciencelab.com/xMSDS-Theobromine-9925229+Theobromine+MSDS&hl=en&ct=clnk&cd=1&gl=uk&client=firefox-a

 

just look up the MSDS for it.

I don't think the original question is about the exact solubility, but about why it dissolves much better in acids or bases than in neutral conditions.

BTW, if you think Wiki's wrong then why not correct it?

 

Hah, I would but I don't know all the details of everything yet;) It's ok as a starting point, but should never be used for reference.

It's not that I think it's rubbish in every aspect, but considering I could just go in there and change it with no knowledge on a subject...I think that says a lot about it's reliability:)

 

Anyway, thanks for advice everyone. Yes the question was about why it dissolves in acid and bases and not water. I think acids, bases and pH7 of water is a hint. Maybe it's because it's zwitterionic and needs a definite electron acceptor/donator. I think. The structure must have something to do with it, but I'm not entirely sure what...

Theobromine means.... Theo(God) + Bromine.... hahahahahaha!