Separation between Sodium salt of p-Cresol and p-Cresol

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PRAVEEN PALIWAL
PRAVEEN PALIWAL's picture
Separation between Sodium salt of p-Cresol and p-Cresol

Hellow,

I want help to separate the above describe. I got a Na-salt of p-cresol and told by R&D tell us the unreacted p-cresol.
I did the derivatization with chloroacetyl chloride and inject on HPLC as per attachment, I got around 16% p-cresol in the mixture. It gives me some of doubt.
I want to know from u all that there is another procedure to derivatize and separate these two on RP-HPLC??? If yes please suggest me.
If now then tell me how can I measure the actual concentration of salt???

Best regards

Praveen

Dr. Analytical
Dr. Analytical's picture
Praveen:

Praveen:
I think it would be easier to do a simple titration.  If you titrate with standard acid you can determine the amount of the salt.  If you titrate with standard base you can determine the amount of free acid.

Derivatization may not be successful because both forms may react.
 

PRAVEEN PALIWAL
PRAVEEN PALIWAL's picture
But what about of free base

But what about of free base (NaOH ) which may e present in the salt. Becasue this salt is prepare by the reaction f p-cresol and NaOH .

Dr. Analytical
Dr. Analytical's picture
p-Cresol is a weak acid and

p-Cresol is a weak acid and OH- is a strong base.  When you add hydroxide, all of it will react with the cresol, assuming that you have more moles of cresol than of base.

For example, if you have two moles of cresol, and add one mole of base, that one mole of base will react with one mole of cresol, forming one mole of the salt.  You will then have one mole of cresol and one mole of Na salt. 

There will be no hydroxide in the mixture.

As I suggested, you could perform the titration both ways, to check your answer.  Then you could confirm that there are no other acids or bases present.

PRAVEEN PALIWAL
PRAVEEN PALIWAL's picture
So as per your concern I have

So as per your concern I have to perform simple acid base titration????

Dr. Analytical
Dr. Analytical's picture
Yes.  I think this is the

Yes.  I think this is the easiest way to determine the amount of each form that is present.