Hi, I'm vacuum distilling a 250degC Alkyl Malonic Ester in the apparatus pictured. When I set the oil-bath temperature and then adjust the vacuum I
get pronounced frothing and bubbling.
But if I set the vacuum and then let the temperature increase slowly the distillation proceeds at the desired 140degC.
Why this difference?
I attach an image of the vacuum distillation setup. A small needle valve & hose clamp maintains a vacuum of <10mm (vacuum oil-pump.) The
heating has a magnetic stirrer (750rpm). Regards F.
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