biomechem - 15-8-2016 at 15:08
Could you tell me is there any difference between the following temperature measuring methods:
a) Sticking thermometer or thermocouple directly into flask or it's neck
b) Sticking it to a water/ silicone oil bath in which reaction flask is inserted
Except a case when in a reaction flask there are substances that may react with thermocouple (e.g. mineral acids). I will be grateful for your help.
Magpie - 15-8-2016 at 15:17
As a rule of thumb for heating the bath should be ~20°C hotter than the liquid being heated.
biomechem - 19-8-2016 at 18:30
Never heard of it, thank you. Could you tell me, please, when using heating mantle the rule of thumb still obligates?
Magpie - 19-8-2016 at 20:57
The heat transfer with a mantle would not be as efficient so a higher temperature would seem to apply. How much higher I have no idea.
I use a mantle whenever possible for its convenience. I just turn the variac to where I get an acceptable heat delivery. I have never used the
thermocouple built into the mantle to measure its temperature.
Fulmen - 20-8-2016 at 00:34
The best approach will depend on the nature of the reaction. If it's endothermic or neutral a heat bath would work fine as long as you don't need a
very accurate temperature. For very precise measurements or exothermic reactions you should measure the reaction vessel directly.