Secobarbital has a logP value = 2.03 an so is not soluble in water. However, looking at the logS/pH graph on chemicalize, it is marked "Solubility category: High". 
Thank you in advance.

A brief look suggests that the solubility isn’t actually that high at all, about 0.55 g/L, but this would be pH dependant and I’m not sure if my value was of the neutral form or not. 

10 hours ago, hypervalent_iodine said:

A brief look suggests that the solubility isn’t actually that high at all, about 0.55 g/L, but this would be pH dependant and I’m not sure if my value was of the neutral form or not. 

I also saw that value of solubility. The graph on chemicalize remains a mistery to me.

Thank you for your answer!

logP and logS ?

Are you referring to factors relating to lipid solubility?

Here is page 620 from Aulton that gives a relationship betwwen P and S.

There is more detail in the section on this page 328ff.

2 minutes ago, studiot said:

logP and logS ?

Are you referring to factors relating to lipid solubility?

Here is page 620 from Aulton that gives a relationship betwwen P and S.

There is more detail in the section on this page 328ff.

Thank you for your time. I need to understand the solubility in water. I saw that the logP is 2.03 and thus my molecule is not soluble in water. However the solubility graph on chemicalize tells the opposite.

Just now, JessicaP said:

Thank you for your time. I need to understand the solubility in water. I saw that the logP is 2.03 and thus my molecule is not soluble in water. However the solubility graph on chemicalize tells the opposite.

It doesn’t mean it isn’t soluble in water, it just means it has a higher preference towards the organic phase (usually octanol). Again, it’s entirely pH dependant. You may want to look up some verified data via Reaxys or SciFinder. 

You haven't given us much detail and Aulton is a difficult book to scan, but this page should supply the other detail, or at least point you in the direction of where to look.

As your graph shows (and is discussed in the text) barbitone solubility is pH dependent.

44 minutes ago, studiot said:

You haven't given us much detail and Aulton is a difficult book to scan, but this page should supply the other detail, or at least point you in the direction of where to look.

As your graph shows (and is discussed in the text) barbitone solubility is pH dependent.

 

I would be wary of posting entire pages of text books. I assume it is covered under copyright laws? If so, you may wish to consider removing them from your posts.

18 minutes ago, hypervalent_iodine said:

 

I would be wary of posting entire pages of text books. I assume it is covered under copyright laws? If so, you may wish to consider removing them from your posts.

Thank you!