Studies on the Cooking Mechanism of Wood. XVI. On the Mechanism of Kraft Cooking

Abstract

1. Hydrogen sulphide cooking of α-guaiacyl propanol (VI) gave bis(1-(4-hydroxy-3-methoxyphenyl)-1-propyl) monosulphide (VIII) and disulphide (VII). 2. Vanillyl monosulphide was decomposed with alkali at 130°. Vanillin, vanillyl alcohol and the secondary products from vanillyl alcohol were identified. 3. The mechanism of the kraft cooking process was discussed and a new mechanism was proposed.

Identification of a diagnostic structural motif reveals a new reaction intermediate and condensation pathway in kraft lignin formation

“…In addition, many different analytical methods have been employed to study isolated kraft lignins. For example acetylation with aminolysis, 42 permanganate oxidation, 43 mannich reaction, 44 aqueous titration, 45 FTIR, 45 and oximation with UV-spectroscopy. 46 More recently NMR methods have come to the fore in kraft lignin analysis, with 1D 13 C, 47 – 51 31 P NMR, 51 – 53 DOSY 54 , 55 and 2D HSQC/HMQC, 32 , 56 – 62 methods being used to study the kraft lignin structure and functional group abundance.…”

Flame retardance-donated lignocellulose nanofibers (LCNFs) by the Mannich reaction with (amino-1,3,5-triazinyl)phosphoramidates and their properties

“…When coniferous trees are used as raw materials of manufacturing, lignin mainly consists of the dehydrated condensate of coniferyl alcohol (guacinyl lignin), and occupies 20 to 35% of the cell wall. [7][8][9][10] Because of the advantages of being inexpensive, renewable, available in abundant quantities, and containing various functional groups, such as benzenols, 11 the modication of lignin for improving its functional capacity is currently being actively investigated. For example, the Mannich reaction was used to gra with amines, [12][13][14] and applied to improve the absorbance of toxic metal ions, such as Pb and Cu, as reported by Li.…”