Chemglass CG-4600-01 - Manual (Page 8)

8
3.4 Use with Rotary Evaporators. Your vacuum regulator is ideally suited for use with rotary evaporators. To
demonstrate the simplicity of the regulator, the following example is given.
1. Set the Regulator Selection Switch (6) to the ‘OFF’ position and then turn on power to the DVR. Turn
on the vacuum pump.
2. Enter a set point into the regulator appropriate for the solvent being removed, for example, 300 torr for
CH2Cl2.
3. Place the flask on the rotovap and move the regulator switch from the OFF to the METER position.
When in the OFF position, the regulator isolates the rotovap from the vacuum pump so the rotovap can
be open to the atmosphere while the pump is running. When placed in the METER position, the
regulator evacuates the rotovap to the pressure entered into the meter.
4. When the majority of the solvent is removed, move the regulator switch from the METER to the FULL
VACUUM position. When in the FULL VACUUM position the regulator ignores the set point pressure
and fully evacuates the rotovap removing the last amount of solvent.
5. When all the solvent is removed place the regulator switch to the OFF position and remove the flask.
Place the next flask on the rotovap and move the regulator switch to the METER position to begin the
process again.
For the entire rotary evaporation process the only action needed is to change the position of the regulator
switch. The pump can run continuously and there’s no need to change the set point pressure.
Solvent recoveries from a typical rotary evaporator are shown in the table below.
Solvent Recovery from Rotary Evaporators using J-KEM’s Digital Vacuum Regulator
Regulator
Set Point Solvent
Bath
Temperature
(o C)
Weight of Solvent
Placed on Rotary
Evaporator
Weight of Solvent
Recovered from
Rotary
Evaporator
Percent
Solvent
Recovered
Time To
Evaporate Flask
to Dryness
475 torr Ether 30 239.68 g (338.5 ml) 238.66 g 99.6%
14.6 min.
400 torr CH2Cl2 30 466.68 g (352.2 ml) 465.32 g 99.7%
43.1 min.
300 torr CH2Cl2 30 476.38 g (359.5 ml) 474.88 g 99.7%
22.5 min.
300 torr CH2Cl2 30 471.19 g (355.6 ml) 470.35 g 99.8%
21.9 min.
300 torr CH2Cl2 30 467.79 g (353.0 ml) 465.72 g 99.8%
22.4 min.
100 torr CH2Cl2 30 338.23 g (255.3 ml) 336.42 g 99.5%
5.9 min.
90 torr EtOAc 35 285.41 g (316.4 ml) 284.99 g 99.9%
17.0 min.
50 torr Toluene 50 236.42 g (272.7 ml) 234.91 g 99.4%
15.7 min.
Test Conditions: Buchi RE 111 evaporator equipped with a dry ice condenser.
Vacuum pump ultimate pressure = 0.01 torr.
All tests were conducted using a 500 ml round bottomed flask at the pressure shown.
3.5 Vacuum Requirements. The type of vacuum source (i.e. a high vacuum pump, aspirator, or in-house
vacuum system) has no affect on the regulators operation or performance. The only requirement is that the
vacuum source be lower in pressure than the pressure you want to regulate the equipment at. That is, to
achieve a vacuum or 40 torr in the attached equipment the vacuum source must be at least 40 torr. The
Digital Vacuum Regulator doesn’t create a vacuum it only regulates the vacuum from an external vacuum
source.