Hi, I am thinking about doing a few things that would require me to heat a fractionating flask(like this:http://www.kavalier.cz/fota/ikonub/130-1.jpg) to rather high temperatures(up to 300°C), but I do not want to ruin it. How high can I heat the
flask without risking breaking it?chemrox - 9-4-2012 at 17:08
If it's borosillicate glass 300C should be well within the range. How will you heat it? Flame?µLoop - 10-4-2012 at 05:54
I do not have an oil bath that is suitable for such high temps, so I am planning to heat it with an alcohol burner. I am not worried about the glass
softening from the heat, but I am concerned about cracking. The bottom part of the flask will probably be over 200°C before anything starts to come
over and heat the upper parts and I am worried about the temperature differential cracking the glass. watson.fawkes - 10-4-2012 at 09:02
The bottom part of the flask will probably be over 200°C before anything starts to come over and heat the upper parts and I am worried about the
temperature differential cracking the glass.
Fabricate yourself a shroud for the flask and fill it with a
heat transfer medium. The shroud could be as simple as a tin can, perhaps with a notch cut in it. The medium could be liquid, such as oil or a molten
salt, or solid, such as metal shot or sand.
Regardless of these details, bring the unfilled part of the shroud up past the side-arm so that the upper part receives radiative heat from the lower
part. Aluminum foil may work adequately for this.
Also, you should ask the question about how you'll cool the flask without breaking it.
