The Variable Bed Flow Reactor (VBFR) is Vapourtec’s patented reactor technology developed specifically for solid-phase synthesis. An automatically adjustable reactor piston continuously compensates for changes in resin volume caused by solvent swelling and shrinking, maintaining a uniformly packed resin bed throughout the synthesis. This eliminates channel formation, improves reagent distribution and ensures consistent reaction conditions from the beginning to the end of the synthesis. The VBFR can also continuously monitor changes in resin bed volume throughout the synthesis, providing valuable process information that can be used to detect and localise peptide aggregation in real time.
Application examples
- Fast-Flow solid-phase peptide synthesis
- Polymer-supported synthesis
- Continuous solid-supported chemistry
- Solid-phase oligonucleotide synthesis
- Automated combinatorial chemistry
- Resin screening and optimization
- Process development for scale-up
VBFR features
- Patented technology
- Automatic resin bed compression
- Eliminates channel formation during synthesis
- Maintains constant bed density
- Automatic compensation for resin swelling and shrinking
- Compatible with inline UV monitoring
- Supports high-speed Fast-Flow synthesis
- Reactor volumes from research to pilot scale
Key advantages
Unlike conventional packed-bed reactors, the VBFR continuously adjusts reactor volume to compensate for resin swelling and shrinking throughout the synthesis cycle. This maintains a uniformly packed resin bed, preventing channel formation and ensuring even reagent distribution through the resin. The result is improved coupling efficiency, lower solvent consumption, excellent reproducibility and faster, more efficient solid-phase synthesis across a wide range of applications.
How does the VBFR work?
There are three main components of the VBFR system:
Reactor:
A reactor comprised of a thick-walled glass tube having a fixed plunger at the lower end and a moveable plunger at the upper end. Frits attached to each plunger ensure the packing media is constrained within the reactor and diffuser plates to ensure the flow through the frits is maintained uniformly. The upper moveable plunger is driven by a motor to contain and compact the packing media.
Reactor mount:
The reactor and motor assembly is placed into a heat exchanger. The heat exchanger is contained within a reactor mount, the reactor mount being mounted onto the front of the Vapourtec E-Series or R-Series system in the same manner as all other Vapourtec reactors.
Reactor compression controller:
The reactor compression controller is a control box that senses the compression of the packing material and continually adjusts the compression of the packing material to achieve the desired compression of the material. A manual user interface is available on the reactor compression controller to set both the reactor size (6.6, 10, or 15) and the desired level of packing. In addition to the manual control interface, the reactor compression controller can be controlled by your R-Series software. The change in reactor volume will be logged by the R-Series software. Changes within the reactor can be monitored in real-time.
The Variable Bed Flow Reactor has a 100-fold range of packing adjustments. In this way, large solid particles such as magnesium turnings can be handled as easily as small squidgy packings such as ChemMatrix resins.
Once the chosen packing media has been added to the reactor the operation is as follows:
- Make fluid and sensor connections to the reactor
- Start pumping solvent
- Set the correct reactor size and desired packing density
- Start the controller
- The reactor’s upper plunger will automatically move to constrain the packing until the desired packing density is achieved
- The user may now set upper and lower limits for the upper plunger movement
- After limits are set operation is completely automatic. If mass is added to the packing media or a solvent causes the packing material to swell, the plunger will move to increase the reactor volume and maintain the desired packing density. If a reagent is consumed from the reactor or for example peptide aggregates on a resin, the controller will reduce the reactor volume. All the time the packing material is maintained at the pre-set packing density, there will be no voids and channelling will be avoided.
Four different sizes of Variable Bed Flow Reactor are available
To facilitate reaction optimization leading to scale-up Vapourtec has made four different sizes of VBFR available. The 4 sizes are identified by the internal diameter of the reactor in mm. The available sizes are; 6.6 mm, 10.0 mm, 15.0 mm and 35.0 mm.
6.6 mm diameter reactor
- Working volume: 0.03 ml to 4.0 ml
- Temperature range: Ambient to 100 °C
- Maximum operation pressure: 20 bar
- Suitable for 50 mg to 400 mg of resin
10.0 mm diameter reactor
- Working volume: 0.12 ml to 9.5 ml
- Temperature range: Ambient to 100 °C
- Maximum operation pressure: 15 bar
- Suitable for 100 mg to 800 mg of resin
15.0 mm diameter reactor
- Working volume: 0.4 ml to 21.0 ml
- Temperature range: Ambient to 100 °C
- Maximum operation pressure: 10 bar
- Suitable for 250 mg to 2 grams of resin
35.0 mm diameter reactor
- Working volume: 5.0 ml to 115.0 ml
- Temperature range: Ambient to 100 °C
- Maximum operation pressure: 5 bar
- Suitable for 1 gram to 10 grams of resin
What else will I need to use the new VBFR?
- You will need either a Vapourtec E-Series or R-Series flow chemistry system
- A Vapourtec reactor compression controller module is also required
- The reactor must be mounted in a Vapourtec reactor mount, which incorporates the heat exchanger
- To achieve sub-ambient conditions a Vapourtec cooled gas generator is required together with, access to dry ice, and a supply of dry compressed air or nitrogen.
