Research on FTIR analysis of Populus nigra L. lignin structure changes in different bleaching processes was written by Zhao, Qiang;Sun, Dezhi;Pu, Junwen;Jin, Xiaojuan;Xing, Mian. And the article was included in Advanced Materials Research (Durnten-Zurich, Switzerland) in 2011.Reference of 10543-57-4 This article mentions the following:
To study the bleaching mechanisms of H2O2 bleaching, H2O2 displacement bleaching and H2O2/TAED bleaching, three kinds of lignin bleached with above processes were obtained. Three types of treated Populus nigra L lignins structure were identified and the functional groups were quantitied by FTIR. In contrast, the deacetylation and the breakage of ester bonds in H2O2/TAED bleaching system was much more significant. The total carbonyl group of H2O2 bleached lignin decreased 6.6% while displacement bleached lignin and H2O2/TAED bleached lignin decreased 9.2% and 15.8% resp. The PT bleaching process had stronger oxidability to destroy the syringyl units in lignin. The breakage of ether bonds and alc. hydroxyl dehydration in side chain increased after bleaching. In contrast, the stronger destroyed effect on guaiacyl dialkyl ether bond with PT bleaching processes. The conclusions obtained may interpret H2O2 displacement bleaching and H2O2/TAED bleaching systems have better bleaching efficiency than H2O2 bleaching system. In the experiment, the researchers used many compounds, for example, N,N-(Ethane-1,2-diyl)bis(N-acetylacetamide) (cas: 10543-57-4Reference of 10543-57-4).
N,N-(Ethane-1,2-diyl)bis(N-acetylacetamide) (cas: 10543-57-4) belongs to amides. Because of the greater electronegativity of oxygen, the carbonyl (C=O) is a stronger dipole than the N–C dipole. The presence of a C=O dipole and, to a lesser extent a N–C dipole, allows amides to act as H-bond acceptors. Amides are not in general accessible by the direct condensation of amines with carboxylic acids for two reasons: first, both components are readily deactivated by a transfer of a proton from the acid to the amine and second, the hydroxy unit on the carbonyl of the acid is a relatively poor leaving group. Nevertheless, the formation of five- and six-membered rings is often surprisingly simple provided that other factors can be brought into play to assist in the condensation.Reference of 10543-57-4
Referemce:
Amide – Wikipedia,
Amide – an overview | ScienceDirect Topics