Sciencemadness Discussion Board - Distilation of gas to get petroleum Ether

Distilation of gas to get petroleum Ether

XeonTheMGPony - 17-3-2018 at 06:25

https://en.wikipedia.org/wiki/Petroleum_ether

Petroleum ether is a handy solvent for certain tasks and can be used with energetics as a plastic solvent, or for certain plant oil extracts and de-waxing of hexamine fuel pellets.

The trick is doing it safely. Recently I reconstituted my 500ml supply and thought I'd share my method.

Get a 1L flask and fill to just below center (The gas will expand considerably)

Set up a vigreux column size isn't so important but it will help, if you do not have one this will still be easily doable just longer as you compensate by very gentle heating in a simple distillation mode

Use a vacuum take off adapter and run the tube to a fume hood or out a window, and set up a fan to draw air through the room and out the window as well.

Ensure all joints are clipped and fully engaged, Now it is important to ensure every thing is ready, as once you start do not unplug, plug in, or use any light switches once started! and DO NOT SMOKE!!!! while doing this!

Get your condenser water cooled with ice if using a recirculating system. You may wish to pre-cool your receiving flask (250ml) but I often just accept the slight losage and let the condensate do that, but if you wish to avoid the fuming it will be to advantage to chill the storage bottle and receiving flask.

Double check your apparatus, and start heat off very low, and slowly increase it till you see the solvent front creep up the column, depending on season and room temp the first thing will be butane. I tend to set my heat source to 100c during the distillation, as the lighter fractions boil off the temp will rise. As you'll notice my mantle is a 500ml sized one I like this as the 1L flask is air bathed, which works well for this distillation as you can distill gas with out ever bringing it to an actual boil!

Once this reaches the top wrap your column in a towel or shirt what ever max temp it will every be at is 65c (I terminate mine at 61c).

End of crude run.

Second run, splitting fractions

Clean all gear, combine all crude runs if any previous ones where don.

Re-assemble and fill the 1l flask with crude, have two chilled bottles handy and attach your cooled 250ml receiving flask.

Add ice to your condenser water and start this, allow to cool.

Slowly start the heat on your distillation flask. run until the therm hits your cut off (I use 35c and down as fraction one, and 35c and up to 60 for the second)

Swap flasks to your second and or third, do not boil to dryness.

I use the tailings in my Colman gas stove with some fresh gas, or mix with a bit of oil and paper pulp as a fire starting aid for the wood stove, but you can use it for glue removal and or other solvent uses, the smell will permeate most plastic containers, so store tailings in a sealed metal can or controlled burnt off.

Wikie cleaning procedure (I've never bothered as I mostly use it for de-waxing and such)

Quote:

Most of the unsaturated hydrocarbons may be removed by shaking two or three times with 10 % of the volume of concentrated sulfuric acid; vigorous shaking is then continued with successive portions of a concentrated solution of potassium permanganate in 10 % sulfuric acid until the color of the permanganate remains unchanged. The solvent is then thoroughly washed with sodium carbonate solution and then with water, dried over anhydrous calcium chloride, and distilled. If required perfectly dry, it can be allowed to stand over sodium wire, or calcium hydride.[6]

Some point I'll research the claims and may make a bottle of "lab grade" petroleum ether but as is I find that the above makes a useful solvent for most things with few issues encountered.

SWIM - 17-3-2018 at 13:42

What sort of yield do you get per gallon of starting material?

XeonTheMGPony - 17-3-2018 at 15:59

for 500 ml you'll get just under 250ml worth of 20c - 61c fraction

then when you make your boiling point cuts it varies, colder the condenser the better recovery.

Deathunter88 - 17-3-2018 at 21:17

Keep in mind that petroleum ether is mostly saturated alkanes, whilst gasoline is full of unsaturated olefins/alkenes, making it much more reactive. The petroleum ether you get from gasoline will likely not be suitable anytime it will contact strong acids, bases etc, but it still might be OK for cleaning grease, as a paint thinner, or a clean fuel.

unionised - 18-3-2018 at 05:21

Or you can buy light naphtha as lighter fluid.
https://en.wikipedia.org/wiki/Lighter_fluid
Doesn't really need distilling except to strip out any garbage it picked up along the way.
Largely saturated hydrocarbons (because crude oil is largely saturated).