Elrik
Hazard to Self
Posts: 52
Registered: 1-9-2018
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2,2,4-trimethylpentane azeotropes with toluene or xylenes?
I've been thinking through theoretical workups for future reactions and I got to a step where dual solvent crystallization with isoöctane and either
toluene or mixed xylenes would be attempted. I recycle solvents whenever possible but I can find no data on the azeotropy of these mixtures. I do see
that a benzene azeotrope exists which is nearly pure benzene but nothing on methylbenzenes of any sort. I suspect if using toluene or xylenes the
distillate would contain more isoöctane, but I dont know how to predict exactly how much.
Does anyone happen to have data on these mixtures? 
I searched the CRC, volume 96 as well as volumes 1-3 of 'Azeotropic Data' from the 'Advances in Chemistry Series'. Are there more comprehensive
sources for azeotropic data that I should obtain?
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fusso
International Hazard
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Registered: 23-6-2017
Location: 4 ∥ universes ahead of you
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What do you need such extraordinary solvents for? Is simpler & more easily accessible solvents not suitable? If not maybe you need to find out
whether said azeotropes exist and find out the boiling point yourself.
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Elrik
Hazard to Self
Posts: 52
Registered: 1-9-2018
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Well, its simple
Toluene is far less toxic than benzene, as well as cheaper.
Xylene is less volatile than toluene and readily available.
Hexanes just dont seem to be available here. n-Heptane is, but its expensive.
When an environmental testing lab phased out HPLC grade 2,2,4-trimethylpentane from their procedures they gave me 16 litres of it for free to avoid
paying to get rid of it, so its my default aliphatic solvent.
Every basement lab has some quirks, right? 
And yeah, I have thermometers and a good range of volumetric flasks so I can get an idea of the composition of a binary azeotrope. It just helps to
know what to expect ahead of time.
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