 In this video, we will show you how to use the rotatory evaporator, or Rotovap in short. When you arrive at the rotary evaporator, generally the glass will be closed. Open it and take your reaction mixture in a single neck flask with a stopper, and for safety, bring a subred ring and place it in a few bottles. First, you can turn on the water, which is generally in the back of the rotary evaporator. It could also be that this is already on, but always make sure to double check. You should hear the water running. It should just be a slow trickle to the rotary evaporator, and that will cool down the rotary evaporator. Now that the water is on, we have to turn on the rotary evaporator. Most of them have multiple button on buttons that you can find either on the top, or at the bottom of the rotary evaporator. This one has one on the top, and there is the on button for the water bath at the bottom. The water bath can be set at different temperatures, but we generally use 40 degrees, but if there are certain solvents that might evaporate very slowly, you might want to increase the temperature to higher temperatures. And the water bath has to be filled with water, so if there is no water in here, fill it with demi-water from the tap available in your lab. When your water bath has reached the correct temperature, in this case 40 degrees, you can attach your flask to the rotary evaporator. All rotary evaporators are equipped with an NS-24 attachment, so if you have a flask with NS-24, this will just fit. If you have a smaller flask, you need to place another attachment here. Place it on the attachment, and make sure to always place a clamp. This clamp will save you from collecting your product from the water bath. Now that our flask is attached to the rotary evaporator, we can lower the rotary evaporator so that the flask hits the water and turn on the turning of the rotary evaporator. Most rotary evaporators either have a handle, electric or manual, and lower your flask till it hits the water, and turn on the rotation. Make sure that it's rotating fast enough, but not so fast that the liquid will actually go into the connector. 40 degrees might not be enough to actually evaporate your solvent, so to make this machine go faster, we will apply a flight vacuum. Start by closing the tap all the way on the left-hand side of the rotary evaporator, and then you can turn on the pump. Make sure that before you turn on the pump that the pressure gauge is all the way in the open position. Turn on the pump, and slowly close the pressure gauge till it reaches the pressure you need for your solvent. Every rotary evaporator is equipped with a list of solvents and the required pressure. In this case, 800 millibars. We close the glass in front of the rotary evaporator and wait until our solvent starts evaporating. Over time, you should see the liquid or the solvent in your flask evaporating, and you should see it condensing in the cooler of the rotary evaporator. If you don't see it condensing in the cooler of the rotary evaporator, it's condensing somewhere else, either just before the pump or after the pump, and you will have to adjust your pressure to make sure that it condenses inside the rotary evaporator, and everything should be collected down in this flask. Now you can see that our flask has dried and that there's only solids remaining in our flask, so we can now turn off the pump and remove the liquid and continue on with the next step of using the rotary evaporator. To switch off, we turn off the pump and open the tab here to let the air back into the system, which is done. And now we have to empty our collection flask in a waste container of the appropriate solvent, and then we will return for the next step. Now that our waste flask is empty and dry, we can place it back on the rotary evaporator and make sure to clamp it tight. When using the rotary evaporator, you want to make sure that your solid is completely dry, so when everything is gone, we will place the rotary evaporator on full vacuum for one or two minutes to make sure that every residual solvent has been removed. To do this, we will close the tab, turn on the pump and close the controller all the way to zero. After we've left our flask on full vacuum for a couple of minutes, we can again turn off the pump and slowly open the tab to let back the air into the system and make sure to open the pressure gauge to the open position so that the next user will not have to do this. Now that the system is back on the atmospheric pressure, we can collect our flask by removing it from the water, turn off the rotation and dry the outside of your flask with a bit of paper. Now carefully remove the flask from the rotary evaporator and place a stopper on the flask and take it back to your fume hood to continue on with the rest of your experiment. Make sure that when you're done with the rotary evaporator that everything is back to its original position, the flask is empty, everything is dry and that the next user can use it. This is how you operate a rotary evaporator.