An application of plastic microchannel-microheater chips to a thermal synthetic reaction

Polystyrol microchannel-microheater chips were fabricated on the basis of imprinting and photolithography techniques. The solution (i.e., methanol) temperature in the vicinity of the microheater (width = 100 or 200 microm and length = 100 microm) integrated in the channel (width = 100 microm and depth = 20 microm) was evaluated on the basis of the temperature-dependent fluorescence lifetime of Rhodamine B as a function of a flow rate and the voltage applied to the heater. The study demonstrated that the fabricated chip acted certainly as a microheater. The chip was then applied to the thermal reaction between benzaldehyde and malononitrile in methanol. Under optimum conditions, benzilidenemalononitrile as the product of the reaction was obtained in a 96% yield with the reaction time of 84 s.