Making Glycerine

[Jacob Kell]

I spent a considerable time searching some info on how to make glycerine, but I didn't find anything useful. I searched the forum and soap making sites but found no details on actual synthesis (using animal fat and lye, separating soap and glycerine, distilling it, and so on). It was a frustrating search, especially because I clearly remember having this recipe somewhere (and losing it). I don't have problem obtaining glycerine from pharmacy for NG synthesis, but also would like to make my own. I hope someone is willing to show me where to find this information.

[stupid939]

The following site is probably where you read about the synthesis of glycerin.

http://frogfot.com/synthesis/glycerol.html

If you read all of the literature, it says (unlike in the procedure section) that you can heat the mixture below the boiling point of methanol, and by doing this you will not have to reflux anything. This method would probably be the easiest way to make glycerin at home without lab equipment.

[Jacob Kell]

Thanks for the link. Do you know more about the saponification procedure? In the text it is dismissed as laborious and complicated, however I am interested if glycerine can be purifyed without methanol?

[bobo]

saponification comes down to heating the fuck out of a fat with lye and water. Transesterification is the same, but with lye and water free alcohol.

The shit with saponification is that glycerol likes the fatty acids too much to come out. It doesn't like biodiesel, however, so a layer separates. This is what he means with difficult workup.

I can confirm that a good amount of glycerol is produced using methanol. Ethanol can be substituted for methanol and for biodiesel, you want absolutely 0% water during this reaction. Though I think, if you use 96% ethanol, the glycerol might be OK even if you get a glob of soap and messy ester (but since you plan to discard it anyway...).

[Nitric-producer]

I cannot easily get high concentration Methanol/Ethanol, will the Saponification procedure yield any Glycerine? I did once make biodiesel, but it did not work that well.

[Shalashaska]

Not that I'm not completely supportive of the ability to make chems at home, but just out of curiosity, is this something you're doing just do it? It's not one of the main chems commonly used like Al Powder, KClO3 or H2SO4 or anything blatant like that.
I'm just saying this because I don't think pharmacies or even supermarkets will ever stop stocking U.S.P. (0% water) grade glycerin.

[stupid939]

From what I have read, pretty much anywhere in the world, people can get ~99% ethanol from "Denatured Alcohol", "Denatured Spirits", or a similar solvent sold in hardware stores or supermarkets. I just did this to save you some time searching RogueSci.

Methanol can also be bought in the USA as "HEET - Gas-Line Antifreeze & Water Remover". I don't know where you live Nitric-Producer, but similar automotive products can be bought around the world, and they usually contain almost 100% methanol.

bobo suppied the information that you were looking for, so I would recommend that if you do intend to make glycerin, you use ethanol or methanol.

[Jacob Kell]

I know the biodiesel procedure, there is plenty of them on "sustainable living" sites, both with ethanol and methanol, but what I am asking is, theoreticaly, if I wanted to further purify glycerol as much as possible after saponification (heating fat and lye, then precipitating with Nacl, without using alcohols), what should I be doing next?

Also, I don't have problem buying it from pharmacy (however it also needs to be heated for a few hours in order to drive the water out of it) in small quantities (50 ml) for NG synth, but I wouldn't mind being able to make it myself, just in case they start controlling it one day.

[megalomania]

With the rising interest in biodiesel production, and in utilizing as much of the waste products as possible (with glycerol being the top) there is growing interest in using the resulting glycerol. I have seen a few websites in my day about trying to recover and purify the glycerol. Most recently I read about a more economical process to convert it to propylene glycol to be used as antifreeze (a higher value commodity than glycerol).

I think the patent database might be your friend. A prefunctory search revealed US patent 4655879 Glycerol distillation process; and US patent 5527974 Process for the purification of glycerol water.

It looks like this guy had an aborted university project to purify glycerol from biodiesel production last year... http://www.engr.wisc.edu/studentorgs/uwfec/website/projects/purification.html