Reduced-pressure distillation device consists of distillation, pumping, pressure measurement and protection of four parts.
Note: ① Decompression distillation should be Kirschner distillation head, with a branch of the liquid receiving tube or use a multi-head liquid receiving tube.
② need to replace the zeolite with a capillary tube to prevent boiling.
③ Requirements for heating with a hot bath, the need to use thick-walled pressure-resistant glass instruments.
Four, Steps in Vacuum Distillation:
1, according to the diagram to install the instrument, check the air tightness of the system. First tighten the screw clamp on the capillary tube, open the two-way piston on the safety bottle, then turn on the pump to pump, and gradually close the two-way piston, the system pressure reaches the required vacuum degree and remains unchanged, indicating that the system is airtight. If there is a change in pressure, it means that the system is leaking, check the interfaces respectively, and add a small amount of vacuum grease to seal it if necessary.
2, add the liquid to be distilled, not more than 1/2 of the volume, close the safety bottle on the piston, open the pump pumping, through the spiral clip to adjust the capillary tube into the air, so that a series of small bubbles is appropriate.
3, when the system reaches the required pressure and stability, open the condensate, hot bath heating, distillation, control the distillation rate of 1 ~ 2 drops / sec.
4, distillation is complete, withdraw the heat source, slowly open the screw clamp on the capillary tube, and slowly open the piston on the safety bottle, balance the pressure inside and outside the system, and then turn off the pump.
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