Formation and Identification of Cis/Trans Ferulic Acid in Photoyellowed White Spruce Mechanical Pulp

Abstract
Direct studies of photoyellowed unbleached white spruce refiner mechanical pulp have been carried out using laser Raman spectroscopy, gas chromatography/mass spectrometry (GC/MS) and Fourier transform infrared spectroscopy (FTIR) techniques. A new chromophore, namely, cis-ferulic acid has been detected. The experimental results indicate the presence of both cis and trans isomers of ferulic acid. The former, because of its yellow color, is considered to be a contributor in the yellowing process.