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Special Report

polyester; polylactic acid; poly(glycolic
acid); poly(caprolactone); poly(ethylene
brassylate); poly(hydroxyl alkanoate).

There is discussion on L-graft-polyester
with the above products. Limitations of
L-graft-polyesters are listed.

There are 162 references. [This review
must be read by anyone interested in
such products.] (Green Chem., 2024;
DOI: 10.1039/D4GC03558E).

Metathesis of sunflower-
derived ethyl esters (SE) and
evaluation of the surfactant Glucose (G) oxidation to and low toxicity. Recycling of BILs is
very important and the use of acid media
potential of the product tartaric acid (TA) makes it challenging. These authors have
mixtures L. Lai et al have conducted detailed studied low-cost and recyclable alcohols
kinetic modelling of aerobic oxidation as antisolvents like ethanol/isopropanol/
C. Lourens et al have worked with higher of G to TA over synergistic bimetallic tert-butanol (TBA). TBA gave 99.7%
purity ethyl oleate (EO) and sunflower AuPt/TiO catalyst at 80-110°C, under high purity recovery. (Green Chem.,
2
oil-based ethyl esters and have used the base-free conditions. This study should 2024; DOI:10.1039/D4GC03898C).
Grubbs second-generation metathesis be useful in the process development
catalyst. EO metathesis was performed of the title reaction. (ACS Sustainable Suppression of lignin (L)
at 50°C with 0.2 mol % catalyst loading, Chem. Eng., 2023; DOI: 10.1021/acs- repolymerisation to enhance
resulting in 67% conversion of unsatu- suschem.eng.3C03807). cellulose bioconversion and L
rated fatty acid esters and a yield of valorisation
47.7%. This is based on the formation Evaluation on the recovery
of 9-octadecene and diethyl-9-octade- of lignin (L) from basic [Ch] T. Pielhop has given an extensive review
cene. In the case of SE, 87.8% feedstock [LYS] systems using low-cost of this subject of considerable contempo-
conversion is reported with 0.4 mol% alcohols as antisolvents under rary importance as we will not run out of
catalyst loading and 50°C giving lower acid-free conditions biomass and it is not in competition with
yield of only 11.6% due to the comple- nutrition production. There is a discus-
xity of the feedstocks. The surfactants are Y. Liu et al have referred to delignifica- sion on additives for preventing L repoly-
non-foaming and applicable in paper tion of lignocellulose using basic ionic merisation, referred to as carbocation
making or textile dyeing industries. liquids (BILs) such as choline lysinate scavengers, such as nucleophilic sub-
(ACS Sustainable Chem. Eng., 2024; ([Ch][LYS]) as a promising method due stances like aromatics, alcohols, amines
DOI: 10.1021/acssuschemeng.4C04758). to its high efficiency, mild conditions, or amino acids. 2-Naphthol has proved to
be a very efficient additive. A number of
other substances are discussed.

There is a discussion on enhancing enzy-
matic cellulose hydrolysis. A cost saving
method is with respect to autohydrolysis
by hot water or steam pre-treatment.
Steam explosion pre-treatment works
well with 2-naphthol as an additive. A
table gives details of different biomass –
spruce, pine, poplar, corn stover and
willow. Glycerol has also been studied
for steam explosion. Glycerol could also

Chemical Weekly February 25, 2025 169

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