The Ion-Exchanging Lignin Derivatives Prepared by Mannich Reaction with Amino Acids

Abstract

The motive of the work was to prepare selective ion-exchangers based on technical lignins. Thus, three spent liquor lignins, namely spruce organosolv (OSL), commercial pine kraft (CKL) and industrial spruce-pine kraft (IKL) lignins, were modified by 1) O-carboxymethylation (CM-lignins), 2) Mannich reaction with glycine (Gly-lignins), 3) Mannich reaction with iminodiacetic acid (IDA-lignins), and 4) carboxymethylation of Gly-lignins (Gly-CM-lignins). The course and conditions of the Mannich reaction modifications were examined on dihydroeugenol s a model compound. The modified lignins were characterized by elemental analyses. The ability of modified lignins to bind metal ions was quantified in batchwise conditions using 5 mM unbufferred Solutions of Cu 2+ , Cd 2+ and Zn 2+ ions, separately. The decrease in concentration after the lignin treatment was measured by the flame atomic absorption spectrometry. The starting lignins were found almost inactive, whereas the modified lignins exhibited ion-exchanging properties with highest values of binding capacity for Gly-CM-and IDA-lignins (up to 0.6 mmol/g). The O-carboxymethyl groups were found to be centres of a non-specific binding and of lower affinity toward the three ions, whereas N-carboxymethyl groups showed a preferential Sorption in the order Cu < Zn < Cd.

Co-curing of epoxy resins with aminated lignins: insights into the role of lignin homo crosslinking during lignin amination on the elastic properties

“…In order to transform lignin into a stronger nucleophile, prefunctionalization with reactive amines can be a useful strategy (Jiang et al 2013;Pan et al 2013;Sun et al 2017). A convenient approach to accomplish this transformation is the treatment of the arene cores of lignin with diamines via Mannich reaction (Brezny et al 1988). Thereby, mechanistically, an iminium ion (Mannich base) is generated as condensation product of an amine and formaldehyde, respectively.…”

“…The functionalization of lignin via Mannich reaction was first described by Brežný in 1988, when studying the reaction of lignin with amino acids (Brezny et al 1988). In the following, the modification method was extended to functionalize lignin with a variety of compounds (methyl and dimethylamine (Ge et al 2015), DETA (diethylenetriamine) (Liu et al 2013;Yue et al 2011), TETA (triethylenetetramine) (Mendis et al 2015), diethanolamine , urea (Zhang et al 2012), etc.).…”

Characterization of structural and physical properties of dichloromethane- and methanol-fractionated Kraft lignin and its adsorption capacity of Cu (II) and Ni (II) ions

“…KL could be considered an aromatic, renewable material with a high content of carbon (~60%). Along-20 side common adsorbents of metal ions such as activated carbon, KL has been investigated as an agent for trapping metal ions in water solvents [9][10][11][12][13][14][15][16][17]. The most important functional groups that support the metal binding behaviour of lignin were identified as 25 phenolic and carboxylic groups [15].…”

“…The most important functional groups that support the metal binding behaviour of lignin were identified as 25 phenolic and carboxylic groups [15]. The mechanism for removing metal ions from water by lignin has been described as a parallel effect of surface adsorption, ion exchange and complexation action [8][9][10][11][12][13]. Primary factors influencing the metal sorption capacity of KL are 30 suggested as being the pH of the environment, ionic strength, the surface properties of lignin and reaction time [15,16].…”

“…[18,19]. Enhancing the adsorption capacity of lignins by carrying out surface modifications to functional groups, for example via a Mannich reaction with amino acids and oxidation, has previously been reported [9,12]. Most recognized stud-45 ies focus on the chemical modifications of lignin, with a view to introducing specific chemical moieties.…”