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Author: Subject: Petroleum fractions
Chemgineer
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[*] posted on 26-2-2024 at 14:54
Petroleum fractions


So i've been distilling some non-polar solvents (~pentane & ~hexane?) from petrol, what i'm not sure of is what to do with the higher boiling point fractions at around 100 deg C.

I could buy a diesel heater off ebay I suppose...
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Rainwater
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[*] posted on 26-2-2024 at 17:43


To the top of a reflux column, attach a distillation condencer.
The temperature of the reflux column should be keeped slightly above the bp of your target compound so that it can escape.

To your reactor/boiling flask, add the solution and a catalyst like alumina (al2o3).
That should get you some lower boiling point compounds.

Your gonna need a metal reactor, copper is not recommended as it will decompose your products, maybe stainless steel. Big petro uses quartz lined reactors

Anyway, let the solution reflux, the alumina will crack long chain molecules into all sorts of toxic and interesting stuff.
Sulfer will kill your catalyst, so will transision metals.

The output of the reflux condencer will be a variety of things that will need fractional distillation to seperate. Industrialy this is done in-sute with a reboiler and reflux tower, but batches can be done in the lab safely.
Would love to compair notes.
Biggest trend i have seen is reactor material and reflux temperature. Lower temperatures crack things in the middle more than higher temps. Gives more double bonds stuff to, at the cost of time, the wrong reactor material goves carbon and h2 gas
I was able to get few good solvents from diesel using this method.
Takes a lot of work and is cheaper to buy it.

[Edited on 27-2-2024 by Rainwater]




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Sulaiman
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[*] posted on 27-2-2024 at 03:33


Quote: Originally posted by Rainwater  
The output of the reflux condencer will be a variety of things that will need fractional distillation to seperate
this is the part of amateur chemistry that frustrates me,
analysing my reaction products.
eg In this case I could measure bp ranges easily
determine if a double-bond is present, or an aromatic ring, with some effort.
I doubt that burning, smelling, measuring density etc would be of much use to me,
so I'd have very little idea what reactions actually occurred.
Also,
Why not use a (possibly sacrificial) borosilicate pot/flask?




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Rainwater
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[*] posted on 27-2-2024 at 07:49


The sacrificial reactor is a personal choice,
I run my reflux 530c.
I use black iron pipe( mild steel ) with an aluminum tube sticking out of the end.
The pipe is long enough to act as a reflux column. The tube feeds a rbf with a fractional column attached. To ugly to photograph and not a good source of alkanes unless you have no other options.
When i tried a copper tube, i got some flammable gas, but almost nothing that condenced at 0c.
When i get time this is on my list to revisit.
I want to try different catalyst/temp combinations and see what bp the different fractions have.




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