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Sulaiman
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I'd go for 500ml because it's cheaper,
. a few hundred ml is enough for most purposes (H2SO4, Hg etc.)
. for pyrolysis a 500ml flask could be sacrificed, a 4l isn't cheap
. a 500ml heating basket/liner/elememt for a DIY mantle is quite cheap via eBay etc.
Although magnetic stirring is nice to have, its not easy to DIY for high temperatures and probably too weak for pyrolydis
Consider DIY overhead stirring, or no stirring.
CAUTION : Hobby Chemist, not Professional or even Amateur
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monolithic
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Quote: Originally posted by Fyndium  | I was just looking for a one. Considered ordering a MESE mantle but after seeing negative rant about their hotplates just not heating and stirrers
jamming I'll look into elsewhere.
Main issue with mantles seem to be their size sensitivity. I have rather wide range of flasks, generally 0.5L, 1L, 2L and 4L which I routinely heat
depending on case so I would still need the bath. Otherwise, if it would be used only for high temp ops, I could probably do with 1L.
For the record, I've been heating the silicone oil now for several hours at 160C and it has pretty much stopped smoking. It can only be seen with a
strong flashlight when other lights are shut. |
eBay is a good place to look. There's always used Glas Col (and similar) mantles for sale, or you could buy what they call an "inner sleeve" from a
Chinese supplier on eBay and make your own housing for the mantle, or you could do the same with some flexible high temperature heat tape.
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Fyndium
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I'm not that keen into making equipment myself when I want high quality and reliable systems and it's definitely not a con if it doesn't look like
homemade. I have found myself into an endless cycle of testing, buying, trying and developing infinite pieces of puzzle even before getting into the
main thing of actually synthesizing something. Perhaps I'm not very good at doing stuff myself, for that matter.
Has anyone got experience on Deschem heating mantles? The supplier is my go to because they deliver stuff very fast and it has usually been good
quality.
By the way, I found the CRC Europe sells 5 liter tin cans of silicone oil that is rated up to 200C and it appears to be of same quality that my
current oil and it costs only 40€ for the 5L tin. Should this be suitable for heat bath, and why the CRC europe MSDS lists that it contains two
compounds of 25-50% of hydrocarbons, C7 alkenes and it is classified as flammable with flash point of -35C? I presume this is a typo because none of
these apply to any form of silicone oil whatsoever.
[Edited on 13-9-2020 by Fyndium]
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macckone
Dispenser of practical lab wisdom
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most mineral oils are going to be fine up to 220C or so (some smoke but no fire) - swan mineral oil flash point is 220C.
canola oil is my go to for lower temperatures, primarily because I use it for frying and have lots of waste oil.
advocado oil has a higher smoke point but is ungodly expensive.
safflower is almost as good as advocado but not as expensive (half the cost) while still way more than canola.
If you need more than 220C you should probably be using a fitted mantle, sand, radiant heat or flame.
A propane/butane stove with fitted ceramic protector (high temp fiberglass) or wire mesh (stainless steel screen) can provide even heating while
protecting glassware from direct flame.
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Fyndium
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Smoking is an issue at my workplace because I work indoors and have only activated carbon scrubber in my fume hood. Though the very high temp jobs I
carry out elsewhere anyways.
I could actually get avocado oil for a very cheap price, but it apparently is (at least more) flammable than silicone oil and it could possibly have
some issues with stability over time due to rancidity, biological growth, etc?
I used canola oil as heating bath for a long time ago but I remember only that I had smoking issues with it - and also the only time ever I've gotten
a bath fire. I truly wonder if I heated it too hot, actually, because I did not have thermometer for the bath. The smoke point difference between
canola and avocado oil is only 30C though.
Also, when heating oil baths, could it cause smoking if the heater is too intense, like from ordinary hotplate or gas burner(a no-go for the matter of
flammable hot oil) even if the base oil temp is way lower than smoke point?
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macckone
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Even silicone based oils aren't going to get you much above 200C.
They break down and smoke as well.
Dot5 brake fluid has a flashpoint around that temperature.
Yes, it will burn.
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