[vizio123321]

My friend was doing an extraction of a primary aliphatic amine - sulphate salt from an aqueous solution.  The amine has little to no solubility in water in the base form.  Additionally the base form is liquid at room temperature.  Here is how it went,,,,

A tube of about 300 mg of the amine salt and other water soluble impurities were dissolved in 7 mL distilled water.  To this was added approximatley 300 uL of 10 M NaOH.  The calculated pH was between 13 and 14 but not directly measured.  The solution was mixed well and turned a milky white color.  It was left to set for 5 min. and an oily layer formed on top.  To this was added 7 mL of diethyl ether.  The solution was mixed and allowed to settle for 10 min.  The top (ether) layer was removed and placed in a seperate tube and the aqueous layer was re-extracted with approx. 4 mL diethyl ether.  The solution was again mixed and allowed to seperate and the top ether layer was added to the original and the aqueous layer was discarded.  A dilute solution of H2SO4 was prepared (i'm guessing around 500 mM)  the pH was around 3.3.  10 mL of the H2SO4 solution was now added to the diethy ether and mixed.  The solution was allowed to settle for 10 min, and the bottom (aqueous) layer was extracted with a pipette.  The remaining ether was re-extracted with another 5 mL of the H2SO4 solution and added to the original.  The ether layer was discarded.

The aqueous solution was then placed on a plate and allowed to evaporate for 2 days.  At the end of the evaporation, there was a white sort or speckled crust on the plate.  It was hard to scrape off, and some of it could not be scraped off.  This amine salt has certain physical and physiological properties know to my friend.  After scraping what he could, he consumed that, and also redissolved what was on the plate in water and drank it.  He noticed that the effects were NOT characteristic of the amine salt he was trying to purify.  He knows for certain there was little if any amine salt present at the end of the water evaporation.

-The pKa of the basic nitrogen on the aliphatic amine is around 9.5.  

Can anyone help my friend and offer advice on what they think might have happened?  

Where did the amine go?  Should the H2SO4 solution have been more acidic?  SHould he have washed the original ether extract with distilled water?  

He has been racking his brain on this and can not figure out what went wrong.  If there is any advice he would greatly appreciate it.

Thanks

[Doc Oc]

This whole post sounds incredibly suspicious.