Hydrogenation on a shaking machine

The cylindrical vessel A, fitted with taps 1 and 2, is connected by a rubber tube to the levelling funnel B. The vessel A contains 1 litre or more between two marks, with subdivisions sufficing for the required purpose. For calibration it usually suffices to fill the vessel with 

A certain amount of water is always formed when oxide or hydroxide catalysts are used. If additional catalyst has to be added or the previous batch regenerated by oxygen, the hydrogen in the vessel must, of course, be previously removed by evacuation and before hydrogen is readmitted the vessel must be re-evacuated to avoid a hydrogen-oxygen explosion. 

For larger batches and moderate overpressure (up to about 3 atm) the apparatus illustrated in Fig. 2 is suitable. 

An iron tank A of 20-1 capacity, and tested to 6 atm carries a manometer B and needle valves 1-3. The hydrogen bomb is securely attached to the tank by a Tombak or an armoured rubber tube. 

For the. first filling, the tank is evacuated through valves 1 and 2, with valve 3 closed, by means of an oil pump, then hydrogen is admitted from the bomb to a pressure of 3 atm of course, the leads must have been previously cleared with hydrogen. If the tank is tight, which is tested on the manometer, valve 3 is connected to the shaking apparatus. 

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