Abstract
This paper presents the visualization of neutralization reactions of an acid (HCl) and a base (NaOH) in a microchannel. Increases in temperature and concentration of the products, caused by the neutralization reactions, are visualized by using the absorbance images at two wavelengths in a near-infrared region: 1412 nm and 1442 nm. Absorbance images at 1412 nm reflect the temperature increases because the absorbance increases with the elevation of temperature. Absorbance images at 1442 nm reflect the concentrations of the products because the absorbance is insensitive to the temperature but sensitive to the concentrations. The absorbance increment caused by heat generation is observed at 1412 nm and that increment caused by products, salt and water, is observed at 1442 nm, respectively.
