Removing glycerol from biodiesel

[Elite Engineer]

So, I'm making biodiesel. I try to separate out the newly formed esters from the glycerol and salts by adding water to a test tube, then the biodiesel on top. I VERY gently invert the tube once or twice, and keep getting a emulsion forming. The solution is completely golden yellow and very translucent. Once gently mixed it all becomes a cream color and cloudy.

 

How else can I remove glycerol? I tried ethanol but the esters are pretty miscible in it.

Edited August 2, 2015 by Elite Engineer

[Enthalpy]

Centrifuge?

[John Cuthber]

You might try pouring off the (mainly) diesel layer into a second container and adding salt to it then stirring.

[Elite Engineer]

You might try pouring off the (mainly) diesel layer into a second container and adding salt to it then stirring.Do

Would NaCl suffice or would ammonium sulfate or magnesium sulfate be necessary?

[hypervalent_iodine]

Would NaCl suffice or would ammonium sulfate or magnesium sulfate be necessary?

.

 

A solution of saturated NaCl should work.

[Elite Engineer]

.

 

A solution of saturated NaCl should work.

Thanks!

[John Cuthber]

In my experience, crystaline salt works better. I think the salt grains give the water something heavy to stick to

[hypervalent_iodine]

In my experience, crystaline salt works better. I think the salt grains give the water something heavy to stick to

 

I've never tried this myself, but that's a good suggestion (and one I'll definitely remember next time I have a tricky emulsion to get rid of).

[John Cuthber]

Old chemist's trick (passed on to you all by an old(ish) chemist)