Various factors influence the distillation rate of a Rotavapor^®. The following tips help you to improve the efficiency of your distillation process, to conserve energy and to reduce the environmental impact. The following charts show the distillation rate of acetone as a function of temperature, rotation speed and flask size, respectively.

Heating bath temperature:
A high heating performance (i.e. > 3.6 kW) only affects the distillation rate at high heating bath temperatures. For a difference of 20 °C or less between the vapor and bath temperature, distillation rates of a R-220 Pro, R-220 Pro High Performance or R-250 are identical.

To make use of the high heating power of a R-220 Pro High Performance or a R-250, set the bath temperature as high as possible

Rotation speed:
High rotation speed produces maximum turbulence inside the flask resulting in higher evaporation rates. However, for highly viscos samples,  some foaming products, or spillage of heating media (e.g. when a drying flask is used), high rotation speed is not applicable.

Recommendation: The higher the rotation speed, the faster the distillation.

Flask size:
The larger the surface of the sample inside the flask, the higher the evaporation performance. On the other hand, large flasks are more difficult to handle and the sample is distributed over a larger area when evaporating to dryness.

Recommendation: The sample volume ideally fills 1/3 to ½ of the flask size.

Despite the wide range of glass assemblies and accessories, customer-specific needs often require customization of standard items such as:

• Additional sensor port on the condenser
• Overall height reduction to fit Rotavapor^® into a small fume hood
• Additional coil for active cooling of the heating bath
• Electroconductive glass coating for Ex zones
• Connection joint for burst disc and non-reclosing pressure relief

BUCHI’s vast experience and profound knowledge make us the ideal and competent partner in advising customers.
We develop and produce our instruments ourselves, which allows us to modify certain instruments or even manufacture a special part according specific customers need.

By concentrating your product the main focus is on speed to ensure the product is not exposed to heat
for a long time.

Common situations during the concentration process:

• Bumping or foaming product
• Uncontrolled concentration to dryness

Recommendation:

• Descending glass assembly to ensure, that not product will accidently end in the receiving flask by bumping or foaming product.
• Optional foam detector
• Level sensor for defined concentration to a specific volume

The main focus to recycle or purify solvents is to get the distillate as clean as possible. With a high recovery rate.

Recommendation:

• The design of the descending assembly guarantees a better separation.
• Additional condenser to reduce the emissions of low boiling solvents
• Foam detector for foaming products
• Level sensor to stop at a defined distilled volume

BUCHI’s Industrial Rotavapor^® features various safety measures:

• P+G coating: All glass parts of R-220 Pro / R-250 are coated with transparent and highly robust plastic (except evaporating flask)
• Protection shields/grids: Optional accessories to protect glass assemblies from potential damages by external influences
• Additional condensers: Volatile solvents are trapped using glass assemblies with additional condensers (see glass assemblies)
• Safety cut-off: Overtemperature switch to protect operator and sample
• System failure: Automatic system shut down into safe mode in case of major failure

AutoDest – Distill automatically without supervision

The AutoDest sensor combined with the Interface I-300 Pro enables unattended automatic distillation by automatic vacuum adjustment according to the required cooling capacity of the condenser. Solvent emissions into the laboratory atmosphere are thus minimal as condenser overload is avoided.

Sensors and valves – Define your degree of automation

Different automation levels are possible depending on the accessories chosen:

• Foam sensor: automatic detection of foam formation
• Temperature sensors: detection of vapor and/or coolant temperatures for process monitoring purposes
• Flow sensor: automatic coolant flow control (interrupts when capacity is insufficient)
• Level sensors: condensate level detection for safety reasons, for defined concentration levels, or to prevent the sample from drying
• Suction device: to remove sample from evaporating flask without detaching the flask
• Valves: feed, shut-off, drain and aeration valves allow distillate drainage without interrupting the distillation process.