Parr Shaker (Hydrogenator) Cheat Sheet
Preparing your sample • • • • The Parr shaker is built to run on one particular size and shape of glassware, do not attempt to use anything other than the "Parr shaker bottle" in the apparatus. Do not fill the bottle more than 1/3-1/2 full. This may require that large scale reactions be run in batches. Very small scale reactions can be run in test tubes within the bottle, but proper precautions must be taken to prevent the tubes from shattering against the wall of the bottle. See Nick for details. Once you have added catalyst (Pd, Pt, Rh, etc.) maintain rxn mixture under Ar or N2 to prevent flame-up. A 24/40 septum fits loosely in the mouth of the Parr bottle for this task.
Getting started • • • • • • Sign in to the log. Make sure all the valves on the hydrogenator are closed (2 valves on left side, 1 on right, 2 valves on H2 tank.) Check to see that there is a line of vacuum tubing from the nozzle on the extreme left side of the apparatus which runs to the house vac in the adjacent hood. Open the house vac valve at the hood. Fix the blue one-hole stopper (threaded with the plastic pressure line) to your reaction vessel. It should be a snug fit. Slide the cylindrical metal shield over your reaction and place it in the sample shaker. Tighten the two finger nuts evenly and tightly; when you're done, the blue septum should be substantially distorted from its normal shape.
Running your reaction • • • • • • Open the main valve on the H2 tank. Do not adjust the regulator (pressure should be ~55 psi.) Make sure that the small valve at the end of the regulator is also open. Open the valve on the far right of the apparatus slightly so as to fill the reserve tank to 40 psi. (The gauge for the reserve tank is the one on the right.) Then, close the valve tightly. To evacuate your reaction vessel, now open the valve on the back left. Be careful if you are using highly volatile solvents that you don't send your entire reaction mixture up the vac line. Close the vacuum valve on the apparatus. Now that the vessel is evacuated, tighten down the finger nuts on the sample shaker a bit more.
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Pressurize your sample with 20 psi H2 from the reserve tank by opening the valve on the front left briefly. Turn on the shaker (toggle switch, front right) for 30 seconds. Open valve vacuum again (back left) to purge out the H2 and any other residual gases. Repeat this 1) fill to 20 psi 2) shake 30 sec 3) vacuum purge sequence a total of 3 times. Finally, with all other valves closed, refill the reserve tank to ~55 psi and then close all three valves between the H2 tank and the apparatus. Now pressurize the reaction vessel to your desired pressure by opening the valve on the front left and start the shaker. DO NOT EXCEED 50 psi H2 IN THE REACTION VESSEL! The bottles are not rated for use above this pressure. You may need to recharge your reaction from the reserve tank periodically, as H2 is consumed.
Cleaning up • When your reaction is finished, stop the shaker and purge the residual hydrogen pressure by opening the vacuum outlet on the back left of the shaker. As the pressure decreases, slowly open the valve on the front left to empty out the reserve tank as well. Close all valves. Remove your reaction from the shaker and be sure to clean the rubber stopper. If it is FUBAR, replace it with a new one. Sign out.
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