Many different components are required to construct a complete Schlenk line setup, including the vacuum pump, tubing, manometer and much more. Product recommendations based on personal experience will be provided in this section.
Schlenk lines are typically equipped with rotary vane (RV) vacuum pumps to achieve working pressures down to 1 x 10-3 mbar. RV vacuum pumps are suitable for Schlenk line chemistry due to their excellent vapour handling capability and ease of maintenance (see The 7 Golden Rules of Vacuum Pump Maintenance). The Edwards and Vacuubrand vacuum pumps are popular choices in university research labs.
Flexible tubing allows Schlenk flasks and other reaction glassware to be connected to the Schlenk line and manipulated under an inert atmosphere. Clear Tygon tubing is a popular choice because it is possible to easily monitor if the tubing is dirty and can therefore be replaced before the risk of further contamination. Heavy-wall gum rubber tubing has low vapour pressure making it suitable for connecting the vacuum pump to the Schlenk line and for connecting flasks to the Schlenk line too provided the correct diameter of tubing is used.
Vacuum gauges, often referred to as manometers or Pirani sensors, are used to monitor the pressure in the vacuum manifold of the Schlenk line. Many basic Schlenk lines are not be built to have a vacuum gauge permanently attached, and instead the vacuum pressure is typically measured after the initial assembly (or after cleaning) by attaching the gauge to the tubing. For very sensitive chemistry, it is often imperative to have a vacuum gauge connected directly to the vacuum manifold during day-to-day manipulations to ensure that all of the seals are tight and that reaction glassware has been sufficiently evacuated prior to use. Vacuum gauges are also extremely useful for monitoring sublimations, vacuum distillations and drying solids under vacuum.
Vacuum gauges are typically connected to the vacuum manifold of the Schlenk line through a greaseless O-ring and held securely with a clamping ring. Alternatively, a KF flange allows the vacuum gauge to be connected to the Schlenk line through a greased ground glass female joint. The VACUU.VIEW extended vacuum gauge is a compact design with a digital display that measures down to 10-3 mbar, making it suitable for Schlenk line chemistry.
Silicone grease is the most commonly used grease for Schlenk lines and other vacuum or pressure systems. It is cheap and widely available, but has limited thermal stability and chemical resistance, however it will generally be suitable for most Schlenk line applications.
Fluorinated (Teflon) grease is completely chemically and physically inert, and has a very wide operating temperature. Although it is far more expensive than silicone grease, it’s superior chemical resistance also means that you can say goodbye to contaminated NMR spectra.
Lithelen grease is a silicone-free, hydrocarbon based lubricant that is highly creep resistant making it suitable for permanent components on the Schlenk line such as the stopcocks.
Please get in contact if you have any additional queries or recommendations on Schlenk line equipment.