biomechem
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Measuring/ controlling temperature of a reaction
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.
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Magpie
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As a rule of thumb for heating the bath should be ~20°C hotter than the liquid being heated.
The single most important condition for a successful synthesis is good mixing - Nicodem
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biomechem
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Never heard of it, thank you. Could you tell me, please, when using heating mantle the rule of thumb still obligates?
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Magpie
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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.
The single most important condition for a successful synthesis is good mixing - Nicodem
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Fulmen
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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.
We're not banging rocks together here. We know how to put a man back together.
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