Sciencemadness Discussion Board

Distilling Advice - Recovering mineral spirits from used solvent

Puffie40 - 24-1-2023 at 21:23

Hi everyone!

I live on a farm with a workshop doing some of our own maintenance. We have a parts washer that uses about 10-15 litres of Varsol (Aka Paint thinner, Stoddard Solvent, Mineral Spirits, the list seems to go on...) for washing the oily grime off of parts. Since the price of Varsol, like a lot of petroleum products, is starting to increase, Having an option to recycle the solvent is starting to sound pretty good.

There are Commercial Units available that can do this, but these are either too big or too expensive for what is basically home use. I figure small batches with some lab glass ware will be adequate when we clean the parts washer every 6-8 months.

I'm not really a chemist - I am a electronic technologist by trade, but I do have grade 12 high school education in chemistry and have watched a few of the more instructional amateur chemist videos on youtube; so I feel that while I may know enough of the distilling basics to be dangerous, I also think I understand most of the safety hazards of distilling a organic substance with a fairly low flash point.

What I would like to ask is what special specifications should I look for while shopping for glassware? I see the number 24/40 which I think refers to the taper?

What length of condenser tube should I look for? Would there be any advantage to going for a longer condenser? Most of the kits I've looked at have 200mm condensers.

would there be any use for a fractionating column? I am guessing not since I am not trying to isolate a specific hydrocarbon.

I am attaching a Safety data sheet of the solvent I am working with. Any advice would be greatly appreciated!

Attachment: VarsolSDS.pdf (69kB)
This file has been downloaded 157 times

B(a)P - 25-1-2023 at 01:20

Welcome to the forum!
You are correct, the 24/40 is the joint size. 24 is the diameter of the widest part of the joint and 40 is its length.
Work out the most common joint size in your region and go for that.
You might also like to try someone like Dr Bob if you are in the US. He is a wealth of knowledge and can get you sorted with a used version of what you need, which means you get quality equipment without forking out a huge amount of cash. And great advice from what I have seen.
If you just want your solvent back, no need for a fractionating column for what you describe.
Others here will be able to assist on column length better than me.
You will also need a hotplate or heating mantle.
Best of luck with it.

Rainwater - 25-1-2023 at 01:48

As for recovering what you want
Side reactions will be a big problem.
Any acids in the solution will begin to react at high temperatures
Adding a base to neutralize these acids can cause reactions to

I suggest starting small scale.
Test the ph and bring it to 7
Read all the safety information you can

But don't rule out other methods of separation.
For light oils, a water extraction should get it fairly clean
From the sds it looks like the major product is "Stoddard solvent"
Which is not a single compound.

Sulaiman - 25-1-2023 at 02:06

A few thoughts :
1 10 to 14 litres of liquid needs a 20 litre or more boiling pot or many batches using a smaller pot
I guess that there may be substances in the fluid that would promote foaming
2 you should not leave the distillation running unattended
3 the time taken for a distillation depends upon both heating power and cooling power
4 a 200mm water cooled glass condenser will, at a guess, require you to be present for MANY hours,
you can add multiple condensers in series but
5 you do not need glassware - safer would be metalware
6 as above, a column is not rrquired
So
I suggest that you consider a pot still of the type commonly used for 'moonshine'
Either commercial or diy
Lots of info here ;
https://homedistiller.org/forum/viewforum.php?f=18

Puffie40 - 26-1-2023 at 23:21

Quote: Originally posted by Rainwater  
As for recovering what you want
Side reactions will be a big problem.
Any acids in the solution will begin to react at high temperatures
Adding a base to neutralize these acids can cause reactions to

I suggest starting small scale.
Test the ph and bring it to 7
Read all the safety information you can


I didn't think about the possibility of the pH of the solution being off. Would washing the solution in a Sodium Bicarbonate buffer solution work? I would need to do some filtrations to get the bigger dirt particles anyway, so working a buffer solution wash into that at the same time would not be a big deal.
Quote:

But don't rule out other methods of separation.
For light oils, a water extraction should get it fairly clean
From the sds it looks like the major product is "Stoddard solvent"
Which is not a single compound.

According to wikipedia, Stoddard is a blend of C7 to C12 hydrocarbons.

From my experience, it is heavier than gasoline, but not as viscous as Diesel fuel. Its volatility allows it to mostly dry off the part after it is washed.

a lot of the oils in the grime get dissolved into the varsol. As the solvent gets "used up", the varsol starts to leave an oily residue behind, and its cleaning power diminishes. I'm expecting the left over residue from the distillation will be a thick oil that I can dispose of with the waste motor oil.

I figure as I start up, I will do a couple of distillations with new varsol to establish a baseline.
Quote:

1 10 to 14 litres of liquid needs a 20 litre or more boiling pot or many batches using a smaller pot
I guess that there may be substances in the fluid that would promote foaming
2 you should not leave the distillation running unattended
3 the time taken for a distillation depends upon both heating power and cooling power
4 a 200mm water cooled glass condenser will, at a guess, require you to be present for MANY hours,
you can add multiple condensers in series but
5 you do not need glassware - safer would be metalware
6 as above, a column is not rrquired
So
I suggest that you consider a pot still of the type commonly used for 'moonshine'

That's an interesting point. a one-gallon metal paint can with a hotplate would make a good, inexpensive boiling pot without the open flame risk. I'll have to look some more into that website.

Deathunter88 - 27-1-2023 at 19:57

I don't think it's worthwhile to distill mineral spirits, it's like 40 bucks for 5 gallons.