Lignin Acidolysis Predicts Formaldehyde Generation in Pine Wood

Pinus virginiana wood was heated (200 °C, 10 or 60 min) while dry or after aqueous/acid/base pretreatment in order to reveal mechanisms of formaldehyde (CH 2 O) generation. Consistent with prior reports, among wood structural polymers, lignin was the overwhelming source of biogenic CH 2 O (defined as having a carbon source in wood). Effects of wood extractives were ignored and reserved for a later report. The selection of acid catalyst strongly affected CH 2 O generation as predicted in the acidolysis literature of lignin model compounds and isolated lignins. Lignin methoxyl cleavage was observed but considered an unlikely source of CH 2 O under the experimental conditions. Alkaline pretreatments did not catalyze CH 2 O generation above levels observed using neutral water. Regarding wood-based composite manufacture, the implications are that lignin reactions might be manipulated during hot-pressing. Potential benefits include reduced product emissions and/or novel cross-linking strategies using biogenic CH 2 O. Perhaps even lignin repolymerization could be promoted for benefit, in direct opposition to biorefinery strategies for lignin removal.