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Special Report
and methyl imidazolium trifl uoroacetate
were found to be optimal IL. Process
simulations were done. This strategy of
By solving a formulated
MINLP problem based on CAILD
Solvent design
areas) have further improved via “sepa- selective CMS membrane with respect
ration cogeneration” where most of the to both a cost and energy standpoint.
electrical energy supplied to the HP This strategy has potential compared to
compressor is recovered as steam or Parex process, which is adsorptive sepa-
process heat at/or higher than the reboiler ration. (Ind. Eng. Chem. Res., 2024; DOI:
temperature. Simulations indicate 79% 10.1021/acs.iecr.4C021803). Process design
to nearly 90% of the supplied electrical 0.8
energy can be recovered as usable steam/ Ionic Liquid (IL)-assisted
process heat. This strategy appears to be Extractive Distillation (ED)
attractive. (Ind. Eng. Chem. Res., 2024; for ethylene/ethane separation 0.4 Byproduct(s)
DOI: 10.1021/acsiecr.4C03190). [This column has covered many papers 0.2 IL solvent
Other utilities
on ethylene-ethane (and propylene-pro- GWP (kg CO 2 eq/kg product) 0.6
Techno-economic analysis pane) separation, which is done through 0.0 Steam
of a carbon molecular sieve cryogenic distillation, which entails high -0.2
(CMS)-based xylene isomer capex and energy consumptions. Several -0.4
purifi cation process papers based on adsorptive separation -0.6 Conventional separation [C 1Py][TFA]-based [C 1Im][TFA]-based concentration and process parameters are
have been covered in this column.] process Process evaluation
seperation process
seperation process
C.J. Roos et al have worked on this subject
as high purity p-xylene is required for Y. Lei et al have come out with a novel ED leads to total annual cost reductions
multimillion ton per annum purifi ed tere- strategy of separation by ED using IL. of 46.5% and 69.8%, respectively. Energy
phthalic acid (PTA). These authors have These authors made use of computer-aided consumption is decreased by 41.6%
come out with a techno-economic-analysis IL design (CAILD) for screening of sol- and 42.1%, respectively. (Ind. Eng.
of commercial attractiveness of p-xylene vents. Methyl pyridinium trifl uoroacetate Chem. Res., 2024; DOI: 10.1021/acs. Extractive distillation of
iecr.4C02483).
Evaluation of near-isothermal
phase-change CO capture
2
technology with heat pump
[This column has covered several papers
in the recent past for CO removal with
2
respect to new amines, biphasic system,
catalysing desorption including using
ultrasound.]
D. Chang et al have referred to the absorp- column (EDWC) are considered. The
tion of CO with phase-change solvents,
2
which results in a CO -rich phase and a
2
164 Chemical Weekly July 8, 2025
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Special Report
2,600-ppm to below 50-ppm in the
fi nal permeate, even though two similar
solutes were involved. (Org. Proc. Res.
Dev., 2024; DOI: 10.1021/acs.oprd.
4C00333).
Ordered 2D RUB-15
nanosheets with high loading
in mixed matrix membranes
(MMMs) for H /CO
separation 2 2
[The separation of H /CO continues to
2
2
attract a lot of attention and this column
has covered some papers.]
Z. Yao et al have referred to the promise
of MMMs combining functional fi llers
with polymer matrices for high-effi-
CO -lean phase. The supply of CO -rich better. 40% reduction in energy is repor- ciency separation. These authors have
2
2
phase to the desorber for solvent regene- ted with EDWC using heat pump. introduced RUB-15 nanosheets as fi lters
ration avoids the need for sensible heat as (Chem. Eng. Technol., 2024; DOI: for MMMs to approach parallel mass
a result of the reduction of the amount of 10.1002/ceat.2023004573). transfer channel, which avoids defects.
solvent. The use of a heat pump is sug- An optimized membrane with a 50 wt%
gested to a near-isothermal CO capture Industrial-scale Organic loading rate exhibited exceptional H /
2
2
technology utilising phase-change solvents Solvent Nanofi ltration (OSNF) CO gas separation performance with
2
to recover the reaction heat absorbed by for dimer impurity removal: H permeability of 1,934 Barrer and
2
the CO -lean phase. A Solvent-Technology Enhancing Vitamin D3 selectivity of 44.5, maintaining separa-
Matching Method (STMM) is proposed production tion factor of 16.7 at 125°C. (AIChEJl,
2
for optimisation. The operative range 2024; DOI: 10.1021/aic.18606).
for the MEA/sulfolane/water solvent J. Schutz et al, have worked on the
removal of an azine-dimer (AD) impu- Covalent Organic Framework
evaluated. This work shows that energy rity from 7-dehydrocholestrol (DHC), (COF)/ PDMS mixed matrix
reduction is possible while maintaining a precursor of Vitamin D3. This has membranes (MMMs) for
a capture effi ciency of over 90%. (Ind. been possible by a newly developed, effi cient ethanol recovery via
Eng. Chem. Res., 2024; DOI: 10.1021/ sustainable, hybrid membrane pro- pervaporation
acs.iecr.4C00722). cess, from the idea to implementation.
This is an energy- and cost-effective Y. Wu et al have come out with high-
solution. Here the loss was only 0.1%. ly-permeable ethanol mixed matrix
isobutyl alcohol (IBA) and This is a three-stage OSNF process membranes (MMMs) by incorporating
isobutyl acetate (IBAc) using and the impurity was reduced from COF-300 into PDMS (Polydimethyl-
DMSO
R. Yildirim and B. Unlusu have reported
the process design and intensifi cation
for the title separation. The mixture
was 52 mole% IBA and 48 mol%
IBAc. Both conventional extractive
distillation and extractive dividing-wall
minimum boiling point azeotrope is
sensitive to pressure and vacuum is
Chemical Weekly July 8, 2025 165