Characterization of chemical and mechanical pulps by pyrolysis—gas chromatography/mass spectrometry

Identification of residual lignin markers in eucalypt kraft pulps by Py–GC/MS

“…From the relative peak intensities, it can be seen that, in comparison to eucalypt wood, the residual lignin in the unbleached pulp gives rise to higher amounts of 4-ethylguaiacol (5), 4-vinylguaiacol (6) as well as syringol (9), 4-ethylsyringol (17) and 4-vinylsyringol (19), whereas the amounts of trans-isoeugenol (13) and trans-4-propenylsyringol (27) are much smaller. Similar results have been reported by Py -GC/MS of kraft pulps by Kleen and Gellerstdet [6]. In the unbleached pulp, it was possible to calculate a syringyl/guaiacyl ratio of 5.5.…”

“…Kraft pulps have much lower lignin content than wood, and consequently, a method is needed for the 'in situ' characterization of residual lignin in pulp avoiding the risk of artifacts generated during lignin isolation. Analytical pyrolysis coupled with gas chromatography/mass spectrometry (Py -GC/MS) has already been used for the analysis of chemical and mechanical pulps [6]. Py -GC/MS is a powerful tool for the characterization of complex natural polymers, such as lignin and polysaccharides in wood that requires very small amount of sample and provides detailed information on molecular changes.…”

Oxidative pyrolysis of integral softwood pellets

“…The four alkyl and allcenyl methoxyphenols have stronger antioxidant effects than GuH and GuCHO. Hardwood pellets were not studied but are expected to give rise to a set of 2,6-dimethoxyphenols from hardwood lignin in higher amounts than the corresponding 2-methoxyphenols [6,7]. The 2,6-dimethoxyphenols have stronger antioxidant properties than their 2-methoxyphenol analogues [12].…”

“…Extensive research on controlled analytical pyrolysis of wood at low temperatures has identified a wide range of released compounds, structurally related to lignin [3] and polysaccharides [4]. The quantitative proportions of pyrolytic products have been used to characterise wood-related materials such as wood lignin [5], wood pulps [6] and forest biomass [7].…”

Efficient biomass pretreatment using ionic liquids derived from lignin and hemicellulose

“…Critical to development of a "closed-loop" biorefinery is the controlled depolymerization of lignin and hemicellulose. Depending on the methods used, it is possible to direct depolymerization toward desired product streams, such as aromatic aldehydes, acids, and alcohols (33)(34)(35). For example, classic oxidative methods involving CuSO 4 with NaOH yield hydroxyl-and methoxylsubstituted aromatic aldehydes (36), particularly vanillin and syringaldehyde.…”