Can anyone help with this biodiesel reaction using ethanol.

[countrypaul]

Since getting the glyc to drop is obviously the biggest issue, triggering that by adding a little (or a lot) of previously produced glyc may help.

This sounds very reminisant of the lecture subject about Zeta potential changes to cause solid precipitates to fall from solution - only it is now over 40 yrs since I attended those and can't remember enough about how to effect the changes. 

[Tony]

Ethanol sounds like a right pain.

I wonder if this is a case where using acetone as a co-solvent would help?  There are many papers on this.

Also of interest is this paper where they used IPA as a co-solvent (this seems to be less studied, but IPA is less expensive and more easily sourced).
https://onlinelibrary.wiley.com/doi/10.1002/er.7432

Many things to try, potentially - all of which I would want to see working with Methanol first before even attempting Ethanol.

Of course if this chap is planning to consume the produced biodiesel by drinking (why - it tastes awful?) then any introduced co-solvents would be a very bad idea.

[dgs]

Hi Tony, just sent you a pm asking how we now post photo's.

I've posted a photo ( facebook ) to the guy in Vegas, just waiting to post one on here then I can continue.

Paul, what about adding some pure glycerine (I'm sure this will be available to the chap in Vegas wheras he won't have any normal ex process glycerol) Even though it's clear I'm sure an interface will be visible.

[dgs]

Tony, acetone may have been a good idea except the guy I'm doing the experiment for wants to drink the stuff! Hence the idea to add pure glycerine to encourage the glycerol to drop.

[countrypaul]

You can certainly try pure glycerine, I can't see any reason why that should not work unless its the impurities in the bio-glycerine that triggers the precipitation. Luckily you should only need a small amount as the prices I've seen certainly seem to make it expensive.

[neisel]

https://postimages.org/

[dgs]

Here is a photo of reaction

[dgs]

Thanks for the link neisel.

So, there is the photo (at last) as you can see it just looks like the new oil I started with, presumably the glycerol in the mix isn't dark coloured like our normal methanol reactions. When I added the ethoxide for each stage the mix darkened slightly then returned to the colour as in the picture, very strange.

Next step (probably tomorrow) is to add the pure glycerine to encourage the glycerol to drop.

[countrypaul]

Just out of curiosity, what sort of oil is you are using? I can see reference to new oil, but not as to whether its rape, sunflower, olive etc.

[dgs]

Just out of curiosity, what sort of oil is you are using? I can see reference to new oil, but not as to whether its rape, sunflower, olive etc.

It's rapeseed, I call it new but it's actually waste from an oil supply business, the bottoms of the big tanks they have. When I get it there are some lipids present but they settle out. The oil I used had been glyc washed and showed no titration.

[dgs]

Here is a picture of the glycerol separation.

[dgs]

I added 32mls of pure glycerine to the mix and gave it a good shake. After a couple of hours the dropout was 87mls. So 55mls of glycerol was in there after the 2 stages.  60 mls of ethanol had been used for the 2 stages (of course 20mls had been removed for the 2x 10/90's including some glycerol)

There is about 275mls of liquid in the tube, so 188 mls of bio from 200 mls of oil. With the amount taken for the 10/90 tests I realise things don't quite add up  but I suppose its within experimental error.

[countrypaul]

Remember the densities of oil, alcohol, glycerol and bio are different so the volumes should never balance (though weights should).
Are you going to experiment to determine the minimum amount of glycerol needed to cause the ful amount to fall? How about using the "waste" glycerol from this experiment for the next...

[dgs]

I was rather hoping that there wasn't going to be a 'next' experiment Paul.

The guy from Vegas was pleased to hear it worked so he is going to try and copy it using pure glycerine to separate the glycerol.

I may try and water wash the bio I have produced just to see how it goes.