Page 166 - CW E-Magazine (8-7-2025)

Special Report
distribution. There is a coverage on
how these nanocomposite membranes
can be further developed. (Angew.
Chem. Intl. Ed., 2024; DOI: 10.1002/
anie.202418649).
Continuous chiral inversion
by coupling enzymatic
racemisation with
enantioselective fl uidised bed
crystallisation (FBC)
J. Gansch et al have worked on the
title problem of considerable industrial
relevance as the problem of unwanted
chiral isomers is a serious one. Thus
coupling enzymatic racemisation with
siloxane) by solution blending. These leading to 3.7- and 2.6-fold enhance- Continuous chiral inversion by
membranes were fully characterised. ment in ideal selectivity for CO /N and coupling racemisation two-stage
2
2
The total flux reached 1,515.28 gm CO /CH . (Angew. Chem. Intl. Ed., Preferential Crystallisation
4
2
per sq.m. per hour and the separation 2024; DOI: 10.1002/anie.2024.19532).
factor reached 8.7 at a 3 wt% COF
loading. Membranes had satisfactory Confi nement effects and
stability during six months of conti- manipulation strategies of
nuous operation. (Ind. Eng. Chem. nanocomposite membranes
Res., 2024; DOI: 10.1021/acs.iecr. towards molecular separation
4C02886).
G. Chen et al have emphasized the im-
Modifi cation of ZIF-8 portance of material featuring well-de-
membranes for gas separation fined nanoscale channels, with their
using X-ray radiation attendant inherent advantages, in mole-
cular separation, catalysis and energy
M. Tsapatsis et al have worked on the storage. In this review, emphasis is on
title strategy where with 300 min irradia- nanocomposite membranes that leverage
tion time, CO permeance decreased by the confi nement effects between fi ller
2
only 9% while N and CH permeance and matrix to construct precise nano-
2
4
reduced by 75% and 65%, respectively, channels and regulate the nanochannel
preferential crystallisation is experi-
mentally demonstrated. Experiments
were then done on pilot plant scale and
led to successful, effi cient, and robust
continuous chiral inversion with puri-
ties exceeding 98%. (Ind. Eng. Chem.
Res., 2024; DOI: 10.1021/acs.iecr.
4C01970).
166 Chemical Weekly July 8, 2025
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Special Report
A fl exible phosphate MOF covered. (Ind. Eng. Chem. Res., 2024; (TFC MMM) that can boost producti-
for enhanced cooperative DOI: 10.1021/acs.iecr.4C020272). vity and yet have low cost. TFC MMMs
ammonia capture containing Matrimid mixed with 12 wt%
Highly enantioselective ZIF-94 were prepared by kiss coating on a
D.D.A. Jaysinghe et al (a large number transportation across liquid porous support. CO /N selectivity was 40
2
2
of authors) have worked on a challenging membranes mediated by and CO permeance of 4 GPU. The use of
2
problem in the manufacture of NH by porous Covalent Organic ZIF-94 also helped in stabilizing against
3
Haber-Bosch process where NH is con- Frameworks (COFs) membranes undergoing CO plasticisa-
3
2
densed so that unconverted N +H can K. Zhang et al have worked on chiral tion. (Ind. Eng. Chem. Res, 2024; DOI:
2
2
be recycled and this is energy intensive membranes, which can help in pharma 10.1021/acs.iecr.4C03086).
(global NH production is 150-mtpa and and other industries as optically active Spatial and temporal
3
is going to increase as NH is also a H
2
3
carrier and now there are turbines which API is almost mandated and not its visualization of polymorphic
racemic version. These authors have
burn NH ). A number of adsorbents have demonstrated for the fi rst time that chiral transformations in
3
been considered but life with NH is not porous material can act as mobile carri- pharmaceutical tablets
3
at all satisfactory and in another context ers of bulk liquid membranes (BLMs) to
very low NH concentrations are not enhance enantioselective transport and Oswald et al have used X-ray Diffraction
3
adsorbed in a satisfactory way. These separation. 2D Chiral COFs (CCOFs) Computed Tomography (XRD-CT) as
authors have come out with a new type of were prepared by imine condensations a non-destructing method for molecu-
adsorbent with pore-expansion strategy of a chiral molecule and have excellent lar-level information with special re-
utilizing the fl exible phosphonate frame- water, acid and base tolerance, and solution. This was used to analyse tablets
work, STA-12 (Ni), which has shown have chiral amine groups in 1D porous that have been subjected to a range of
exceptional stability and capture of NH channels. CCOFs with both -F and -iPr
3
at ppm levels at elevated temperature of groups show superior performance. (This
100-220°C and even under humid condi- can be a very useful strategy) (Angew.
tions. A remarkable uptake of 4.76 mmol Chem. Intl. Ed., 2024; DOI: 10.1002/
per gm at 100 µbar (equivalent to 100- anie.202419916).
ppm) is reported. In situ neutron powder
diffraction, inelastic neutron scattering, Thin fi lm composite
and infrared microspectroscopy was mixed-matrix membranes
adopted to study the mechanism. STA- (MMMs) based on Matrimid
12 (Ni) can be engineered into pellets and Zeolitic imidazolate X-ray Diffraction CT images for the tablets compressed to
50 MPa and 400 MPa at t = 4 days (Fresh) and t = 30 days
or monoliths without losing adsorption (aged). The underscore number designates the tablet number.
capacity, making them useful in practice. frameworks for CO /N The white particles indicate the presence of 2-(2-hydroxyace-
2
2
toxy)acetic acid. The XRPD patterns of the pure
(J. Am. Chem. Soc., 2024; DOI: 10.1021/ separation performance compression pressures. A pressure-sen-
acs.4C12430). E. Lasseuguette and M-C. Ferrari have sitive marker, glycolide was used to track
Advances in Ionic Liquid (IL) referred to the development of thin-fi lm changes. (Angew. Chem. Intl. Ed., 2024;
technologies for CO capture composite with mixed-matrix membranes DOI: 10.1002/anie.202412976).
and conversion 2
[This column has covered many papers
on absorption of CO where many
2
advances have been reported.]
C. Numpilai et al have given a compre-
hensive renew of the title subject. ILs are
attracting attention due to their unique
properties like structural tenability,
strong CO affi nity and non-volatility.
2
The transformative role of ILs in con-
verting CO into cyclic carbonates is
2
discussed. Futuristic aspects are
Chemical Weekly July 8, 2025 167