Ok, I assume I have a high MG and DG issue as a vigorous shake test turn everything into a thick emulsion. If I water wash medium gently with repeated 5% washes. Will that remove the the MG and DG.

From what I have read, some mono's will be washed out, but how did this batch do on a 3/27?

Doug
-before you can think back reaction,you must be sure the soaps are gone. then if you still create an emulsion, you are in all probability looking at monos as the problem. this could be from back reaction or poor conversion. 3/27 will detact tryglycerids but not monos or di's.
-monos can be washed out, at least that is what I am told!
-How big of a batch are you playing with? could you take a 1 or 2 ltr sample and do a repo on it then wash to see if it washes any easier? If mono's or di's are the culprit, the a repo shoud fix the problem and increase yeild. Tom

Unfortunately nothing too significant will wash out at all.

Only way of eliminating mono and di's is with thorough reactions. The Formula tom and I have been using makes fantastic fuel which is very high converted. You would do a single base stage. Then for rxn2 u use a repro formula.

The reason for some mono's getting washed out is due to the polar end of the molecule. Water too being polar will bind to the polar end of the mono and drag some out.

Ok, here is my question then.

What causes a sample when water washed to emulsify.

Soap? MG and DG? I first thought it was soap, but then read more and saw MG&DG. Perhaps it is both depending on concentration?

Without removing any soap, I just did a test reprocess. 400ml of 120 degree Soapy Bio (tests at ~3400ppm. 25ml of Methanol (fresh as can be). .5 Gram of NaOH. Shook it up vigorously in a sealed Mason Jar. I will let it sit overnight and check in the morning.

Doug

Doug
-when you water wash in the presence of soap or the byproduct which is soap laden, the soap is ion attracted to the water, if there is too much water, the soap/ water mix will suspend in the biodiesel creating a colloid mass (emulsion) and can be very difficut to seperate as you know.I'm sure I haven't done this chemistry any justice but this is the way I understand it.
-I'm interested to see the results of the wash on the repo batch! Tom

Doug,
Reese said it right.

A Mono has 2 OH groups that are attracted to water and a FFA chain that is attracted to oil/bio. Soap has 1 Na/K and an O that is attracted to water and 1 fatty acid chain that is attracted to oil/bio. Both of them would be capable of creating emulsions.
Di's have one hydroxyl group and 2 fatty acid chains that would make it more attracted to the oil than water.

In esterification, All the tri's are not created into Di's and then all the Di's created into Mono's then all the Mono's into esters. There is a bit of a chaotic reaction of all happening at the same time. I can only imagine in the case of a major reverse reaction there would also be some Tri's created.

Just my .02

quote:

Ok, I assume I have a high MG and DG issue as a vigorous shake test turn everything into a thick emulsion.

Do your samples separate into different layers ? and how long does it take to completely separate? I've had some problems along this line,also. I've done some vigorous shake test and turned the bio and water mix into milk but in time they separate out. Sometimes I get a thick white layer between the bio and water. What's this a sign of? Poor wash, poor conversion ,possibly both? don't know