REACTORS

Chemtrix BV supply a series of standard glass micro reactors, configured for use within our Labtrix® S1 and Labtrix® Start micro reactor development apparatus. The standard micro reactors are manufactured from D293T glass and are fabricated using a combination of wet-etching and thermal bonding techniques. A series of reactor volumes (1, 5 and 10 µl) and mixer types (T- or Static mixers) are available to enable the facile evaluation of reaction time and temperature effects on liquid-liquid flow reactions, with each Labtrix® micro reactor containing three functional areas;

• Mixer - where two (or more) reagent streams are combined
• Residence time unit - time for reaction to occur
• Quench - where the reaction product is mixed with a diluent or terminating agent to stop the reaction and afford a stable sample for off-line analysis

To ensure high reaction selectivity and maximum productivity, efficient mixing of the thermostatted reagents is required. To achieve this the KiloFlow® reactors contain integrated static mixers, which provide mixing times in the range of 60 to 250 ms. After the mixer, the reaction mixture enters a residence time channel where the reaction continues prior to sample collection. The meso reactors contain integrated heat exchangers which maintain the reaction temperature via the use of a closed re-circulating thermostat.

Two sizes of meso reactor are available in the design, a single channel reactor with a volume of 0.8 ml (RS) and a parallel channel reactor with a volume of 6.5 ml (RL). Within the RL, eight mixers are employed in parallel maintaining the same mixing profile as for the RS. In addition, the reaction channel consists of eight parallel but inter-connected reaction channels, affording uniform fluid distribution within the device and maintaining a low pressure drop (RL = 0.25 bar at 100 ml min-¹).

In the standard system, two meso reactors are connected in series, with the reactants mixed in the first reactor and then pumped into the second reactor to afford increased residence time/throughput. By varying the combination of reactor and heat exchangers within the KiloFlow® holder, the user can readily configure the system to access a range of reaction times and system throughputs, tailored to suit the process requirements of a particular reaction; with the system peripherals remaining unchanged. The Table below shows the configuration options building from a standard system using two heat exchangers and two reactors.

As the same mixing structure is used in both Labtrix® and Plantrix®, the product portfolio from Chemtrix BV offers a unique scaling concept that enables facile transfer of reaction methodology developed in micro reactors (Labtrix®) to meso reactors (KiloFlow®) without the need for lengthy and costly re-optimization steps.

In order to maximize system productivity for transformations performed in KiloFlow®, reagents are pre-heated in glass heat exchangers before being transferred to a meso reactor where they are mixed. The heat exchangers are thermally regulated using a closed re-circulating thermostat and comprise of five thermally bonded glass layers whereby the middle layer contains the reactant channel and the outer layers contain a network through which the heat transfer fluid is pumped. Using this approach the heat transfer obtained is four times more efficient than a double tube heat exchanger!

Depending on the system throughput employed, there are two sizes of heat exchanger to choose from, ‘Heat Exchanger Small’ (HES) 0.66 ml and ‘Heat Exchange Large’ (HEL) 2.65 ml.