Preparation of LOX with a cold trap and Liquid Nitrogen:
Equipment used:
Cold Trap with PTFE cock and ground glass joints
Dewars
Three-way stopcock
Air balloon
Silicone tubing
Pressure reducer for Oxygen
Stative and Clamps
Chemicals:
Oxygen in gas zylinder (5 L volume and 200 bar)
Liquid Nitrogen
Preparation:
Connect the pressure reducer to the oxygen cylinder and go with a silicon tubing from the low pressure outlet to the empty cold trap. Fix the ground
glass joint connections with clamps in a way that they can tolerate a little pressure. From the outlet of the cold trap use an adapter for connecting
the three way stopcock in such a manner that you have a gas reservoir with the air balloon.
See Pic1.jpg and Pic2.jpg for detail.
The apparatus was now flashed with oxygen and the gas reservoir (air balloon) was filled with oxygen.
Pic3.jpg and Pic4.jpg
The cold trap is now filled with liquid nitrogen and the gas reservoir collapsed:
To get LOX the flow is in a such manner adjusted that the balloon is filled again:
Pic5.jpg
I got 120 ml of a bluish liquid:
Pic6.jpg
which was tested positive for LOX (cigarette soaked with LOX and lighted):
Pic7.jpg
Here you find further pictures and my original post:
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