Dry Points About Fractions
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This post was last edited by chengkang on 2009-11-5 10:20 Why does the temperature of the gas phase decrease instead of increasing at the end when measuring the distillation range of a fraction? Has all the liquid phase been vaporized at this time? ? ?
The dry point refers to the thermometer reading observed at the moment when the last drop of liquid at the lowest point in the rectifier flask vaporizes during distillation under standard conditions. At this time, the reading of the thermometer reaches the highest point. If you continue to distill, the residue will begin to thermally decompose, and you will see smoke appearing in the flask. Because the decomposition reaction is an endothermic reaction, the temperature will drop when it begins to decompose.