ABSTRACT
Introduction ..............................................................................................................50 Light, Energy, and the Beer-Lambert Law ..........................................................50 Absorption of Substituted Benzenes Related to Lignin ...................................... 51
Benzene .......................................................................................................... 51 Effect of Substituents ..................................................................................... 52
Lignin Model Compounds .......................................................................................54 Soluble Lignins ........................................................................................................ 57
Difference Spectroscopy-The ∆ε Method ........................................................ 58 Color of Wood, Lignin, and High-Yield Pulps ........................................................ 61
Coniferaldehyde and Ferulic Acid ...................................................................... 62 Biphenyls ............................................................................................................. 62 Quinones ............................................................................................................. 63 Metal and Hydrogen-Bonded Complexes ...........................................................66 Stilbenes ..............................................................................................................68
Diffuse Reectance Spectroscopy ...........................................................................68 Basic Measurements............................................................................................69 Pulp-Bleaching Studies ....................................................................................... 70
