Page 169 - CW E-Magazine (12-12-2023)

Special Report

A rapid wrap-up of what’s new in Operations,

Processes and Products

Renewable Raw Materials

Synthesis and computational
investigation of novel antioxi-
dants prepared by oxidative
depolymerisation of Lignin (L)
and aldol condensation of aro-
matic aldehydes

D. Gao et al have made novel antioxidants
(AOs) by CuSO catalysed oxidative
4
depolymerisation of L to form aromatic
aldehydes, followed by aldol condensation
with methyl ethyl ketone (MEK). This
aldol condensation greatly increased the
AO properties. Three monomeric products
from L, viz., p-hydroxybenzaldehyde,
Cadaverine (C ) from L-Lysine vanillin, and syringaldehyde, are further
(L) employed for aldol condensation with
MEK, resulting in successful synthesis
Z. Ma et al have worked on the hetero- of new antioxidants: 1-(4-hydroxyphe-
geneous decarboxylation of renewable nyl)pent-1-en-3-one (HPPEO), 1-(4-hy-
L, obtained through fermentation, to C. droxy-3-methoxyphenyl)pent-1-en-3-one
C is useful for making Nylon 5X. K-Ru Fau (HMPPEO) and 1-(4-hydroxy-3,5-di-
catalyst gave selectivity reaching 76% methoxyphenyl)pent-1-en-3-one (HDMP-
and this too at 100% conversion of L. on the molecular structure of L macro- PEO). p-Hydroxybenzaldehyde had the
C is useful for making polyamides and molecule. DFT modelling was done largest rate to react with MEK. Syring-
polyurethanes. There is a biochemical and three Ls sourced from Kraft and aldehyde-based product had the best AO
route as well, but the title process seems Organosolv processes were considered. ability. DFT was done. These are new
to be more attractive. (Applied Catalysis Conformational differences were consi- ways of valorising L. (ChemSusChem;
A: General, 2023, 658, May, 119172; dered. These authors have demonstrated DOI: 10.1002/CSSC.202300208).
DOI: 10.1016/j.apcata.2023.119172). that LNP particles can be molecularly Robust ionic liquid (IL)/ethanol-
tailored for different application. L has amine-superbase solvents enable
Lignin (L) been proposed for many applications, rapid, efficient and mild dissolu-
such as highly reinforced biodegradable tion of lignocellulosic biomass
Molecular understanding of the composites, tough hydrogel adhesives, etc.
morphology and properties of Many other applications are suggested. Y. Wang et al have used the title combo
L nanoparticles (LNP): Unrave- Manufacturing cost of LNPs is estimated (and organic superbases) for the dissolu-
lling the potential of tailored at US$1 per kg; the potential profit from tion of biomass. This could be done below
applications LNP can reach US$1 per kg if the revenue 100°C. Emim OAc/ EA-DBN system
is US$2 per kg. gave the best performance. Substrates
I. V. Pylpchuk et al have reported that were: Populus tomentosa, sugarcane
the size of LNP particles depends on the All three Ls were further refined by etha- bagasse, and miscanthus giganteus at
molecular weight (Mw) of L. These authors nol fractionation at room temperature. 90°C. This performance is explained.
have shown that for similar Mw Ls, the (Green Chem., 2023; DOI: 10.1039/ (Green Chem., 2023; DOI: 10.1039/
size and morphology of LNPs depends D3GC00703K). D3GC00783A).

Chemical Weekly December 12, 2023 169
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