Ozonation Products of Organosolvolytic Extracts from Vegetal Materials

The ozonation of lignin in an organic solution was used to produce oxyaromatic compounds. Corn (Zea mays) stalk and poplar (Populus deltoides) wood lignin solutions (organosolvolytic juices) obtained from their respective autohydrolyzed materials and an organosolv lignin were treated with ozone, and the time course trend of the identified reaction products was studied. GC/MS and GC/FID were used to identify and quantify (internal standard method) the reaction products. The following acids were identified: glycolic, oxalic, malic, glyceric, p-hydroxybenzoic, and vanillic. In addition, p-hydroxybenzaldehyde, vanillin, syringaldehyde, and hydroquinone were also identified. All the oxyaromatic aldehydes reached maximum yields at short reaction times (between 1 and 8 min). These results were used to determine the ratio between the different phenylpropane units of their constitutive lignins. The ratio of p-hydroxyphenyl:guaiacyl:syringyl units for corn stalk, poplar wood, and organosolv lignins was 5.3:2:1, 0.1:1:1.1, and 0:1:1.1, respectively.