Exploiting the channels
23 Feb 2005
Lab-on-a-chip technology is bringing process industry techniques of flow management and continuous reaction to the research laboratory, albeit on a tiny scale.
The techniques also have potential for industrial processes, especially when hazardous substances are involved. Graham Sandford at the University of Durham is leading research to develop microreactors that can be used for reacting organic molecules with the corrosive and toxic gas fluorine.
Fluorine is an important element for the life science sector, as many pharmaceutical and plant protection products contain carbon-fluorine bonds. However, fluorine is so hazardous that there is an urgent need for safer and more controllable methods of carrying out the reactions.
Microreactors could be the answer, says Sandford — the volume of fluorine reacting at any one time is very small; they are extremely efficient gas-liquid mixers and heat exchangers; and the gas/liquid surface area is very large.
Sandford's team has designed and built a modular microreactor system, consisting of a 'base block' with reservoirs for fluids, machined from stainless steel, combined with a 'channel plate', also made from stainless steel, holding the channels through which the fluids flow.
They used this to carry out a number of fluorination reactions, adding fluorine, using inert nitrogen as a carrier gas, to five different organic molecules. In each case, the fluorine addition was successful.
Sandford says that up to 30 channels can be operated in parallel, making large batches a routine task.
'In theory, all speciality chemicals could be synthesised very quickly and continuously using these very versatile multi-channel reactor systems,' he says.
