Page 178 - CW E-Magazine (28-5-2024)

Special Report

propylureas using a chiral lithium amide. H O . The enzyme P45OExa was found development of innovative PE-based
2
2
The urea derivative is formed with 99% to be highly suitable for the conversion on nano/micro reactors have been
ee+. Further treatment with acid indu- of C-6 caproic acid, giving 95% con- reported. Such a system can provide
ces an “azatropic shift” with retention of version and high regioselectivity with high interfacial area, high conversion,
configuration. (Angew. Chem. Intl. Ed., α to β selectivity of 14:1. Optically etc. Some unconventional reactions
2023; DOI: 10.1002/anie.202216758). enriched products were formed for are covered. Current challenges are
C-6 to C-10 fatty acids. (Green Chem., discussed. (Green Chem., 2024; DOI:
Methylation of naphthalene (N) 2024; DOI: 10.1039/D3GC.04593E). 10.1039/D3GC02512H).
with methanol
[2,6-Dimethylnaphthalene (DMN) is of Pickering emulsion (PE)- Selective enhancement of ethy-
considerable importance and difficult derived nano/microreactors for lene epoxidation via directing
to make, free from other isomers, as it unconventional interfacial cata- reaction pathways over Ag
is required to make the corresponding
dicarboxylic acid, required for PEN, lysis single-atom catalyst
which has good barrier properties and A. Abbas et al have given a state-of [The vapor phase oxidation of ethylene
bottles are retortable.] the-art-review of advances and pers- to ethylene oxide was an important
breakthrough and replaced the pollut-
S. Zhong et al have reported the title pectives in green reactions. PEs are ing chlorohydrin process. Initially the
reaction with Al-modified SiO zeolite an emerging class of surfactant-free yield was just over 60% of theory and
2
catalysts. Temperature of 300 C was dispersions where stabilisation is subsequent continuous developments
o
considered useful. DFT calculations carried out by solid particles, such as have taken the yield to close to 84%.]
were done. 2,7- isomer is also formed. nanoparticles, COFs, MOFs, polymers,
(Ind. Eng. Chem. Res., 2024; DOI: proteins, etc. Such a system appears to Z. Yu et al have come out with an
10.1021/acs.iecr.3c03370). be very promising, and the design and interesting and potentially useful stra-
tegy of using Ag single-atom catalyst.
Methanol dehydration It is also necessary to prevent iso-
to DME merisation to acetaldehyde. DFT cal-
[DME has acquired considerable culations were done. An anchored Ag
importance as it can substitute for LPG single atom on the α-Al O (0001) sur-
3
2
and can also be added to diesel (cetane face acted as a heterogeneous catalyst.
no. 55-60]. Here gaseous C H directly attacks
4
2
oxygen atoms one by one instead of
A.L. Moghaddam et al have used interacting with them simultaneously.
KFI-type zeolites as catalyst and com- This study provides a new perspective
pared with ZSM-5 and gamma Al O for the design of advanced catalysts.
3
2
as benchmarks. Full characterisation (Ind. Eng. Chem. Res., 2024; DOI:
of the catalyst was done. The method 10.1021/acs.iecr.3c04600).
of preparation is given. This catalyst
realised thermodynamic equilibrium
conversion at about 185 C (this is 91%)
o
and maintained activity for over 100
hours. (Applied Catalysis A: General,
2024, 5 Feb, 119594; DOI: 101016/j.
th
apcata.2024.119594).
Preparative regio- and stereo-
selective alpha-hydroxylation
of medium chain mono- and
di-carboxylic fatty acids

K. Bangert et al have referred to the use
of peroxygenases as these require only

178 Chemical Weekly May 28, 2024

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