omg jj my heart is bleeding with this chemical misinformation.
The glycerine is part of the vegetable oil. veggie oil being a triester. It’s not “in it.” It is it. Glycerol is a byproduct because in hydroxide promoted transesterification it is in equilibrium with the (desired) ester product (biodiesel). You probably see very little glycerol because you use a lot of methoxide. Since hydroxide is a much better nucleophile than water, adding more methoxide will shift the chemical equilibrium towards the side of making more ester and water, as opposed to more glycerol and methoxide. I’ve never actually seen transesterification explained in this depth on the internet. They always make it seem like it’s an absolute. Like frying an egg (which is probably not something you want to bring up at a biodiesel convention as I can imagine). You can’t go back to having an egg after you fry an egg. I mean, you can’t go back to having an uncooked egg. Well, actually, you can’t reverse a hydoxide-ion promoted hydrolysis, either. damnit. chemistry. damnit. If we were talking about acid catalyzed (OMG it really is a catalysis reaction, too! I feel so happy about actually being able to use that word correctly) ester hydrolysis whereby the acid donates a proton to make the ester more reactive then we would be graaaaaaaaavy (and this is the method we have been implementing.)
Mainly, regarding the base method, nucleophiles won’t try to attach to a negative molecule. It’s just not a love party they don’t want to get involved with. Actually there’s a reason. I’m not going into the reason. It would be another paragraph.
What did they teach you at this conference! It really doesn’t surprise me (not in a bad way, though). The chemistry of biodiesel isn’t nearly as important as how to make it efficiently, safely and quickly. All the things of which engineers are better suited than chemists to figure out. 