Page 180 - CW E-Magazine (28-11-2023)

Special Report Special Report

For the title NH synthesis the contribu- Advantage is taken of the low-potential of redox reactions. TEMPO-media- per hour and all this in solvent-free
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tion of hot-electron has been assessed. oxidation of HCHO on a Pd membrane ted oxidation of isopropanol to acetone mode and thus eliminating the need for
Here the activation energy is only 5g anode to produce hydrogen that can per- seems to be promising system for ELHP a separation step. (Angew. Chem. Intl.
vs 126 kj per mole for thermocatalysis. meate through the membrane electrode. of different TEMPO. 4-methoxy-TEMPO Ed.; DOI: 10.1002/anie.202304219).
The catalyst was stable for 1,000 hours. It is demonstrated that electrocatalytic appears to be the most promising
This study provides a guide for the dual hydrogenation of unsaturated candidate. (ACS Sustainable Chem. Eng., Isobutanol (IB) to isobutene
design of high performance photother- dicarboxylic acid can be carried out when 2023; DOI: 10.1021/acssusche- (B)
mal catalysts. (Angew. Chem. Intl. Ed., another Pd membrane electrode is also meng.2c07419). J-L. Dubois et al have discussed the
2023; DOI: 10.1002/anie.202304452). adopted as the cathode. Thus reduction title conversion, with respect to pro-
is done on both the anode and cathode Dehydrogenation of perhydro-
Electrocatalytic processes in two separated chambers, leading to N-propylcarbazole (PPC) cesses and catalysts, as this has gained
theoretical maximum FE of 200%. (Nature The transport of much wanted H important for not only getting iso-
butene, but conversion to derivatives,
Electrocatalytic dual hydroge- Catalysis, 2023, 6, 224-233). through Liquid Organic Hydrogen Car- 2 like dimers, methacrylic acid, MTBE,
nation of organic substrates riers (LOHCs) is gaining traction for
with a Faradaic Effi ciency (FE) Highly selective TEMPO-cata- large scale operations (There are indica- multi-million tonnes per annum scale catalytic reactor and it seems to be a
approaching 200% lysed bulk electrooxidation tions that it is partially commercialised). (> 10-mtpa) The present process is at feasible technology. There are exten-
high reaction temperature and pressure sive opportunities for its intensifi -
[This column has covered many papers of isopropanol to acetone for and has problems of safety hazards cation. These authors have worked on
on electrochemical processes, including application in electrochemical L. Liu et al have worked with Pd/
valorisation of CO to CH /C H etc., heat pumping Al O -SiO catalyst for an enhanced and high energy consumption. Carbon coupling between the type of catalyst,
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2
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nitride (g-C N ) with a unique sandwich process conditions, type of membrane,
4
2
4
2
3
in view of renewable energy avail- effect and have studied the effect of structure is a photocatalyst and H. Zhu and reactor operation (isothermal and
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ability in a distributed way.] A. Mishra et al have referred to the Al/Si ratio. With Al/Si molar ratio of et al have used this at room temperature, non-isothermal). Ru- and Co-based
development of more energy effi cient 2:1, Pd/AlSiO catalyst allowed 100% atmospheric pressure, and solvent-free catalysts and a Pd-Au membrane were
G. Han et al have referred to some heat pump technologies for widespread dehydrogenation of PPC in 360 minu- conditions. A continuous fl ow strategy considered. A more holistic approach
intrinsic limitations associated with sub- practical implications. Electrochemical tes and had good stability. (Molecular was adopted to reduce the effect of back is a necessity to get the desired results.
strate solubility and diffi cult separation Looping Heat Pump (ELHP) techno- Catalysis, 2023, 543, 1 June, 113-114; mixing. The catalyst has high effi ciency, (Reaction Chem. Eng., 2023; DOI:
of the products from the electrolyte. logy has emerged as an attractive alter- DOI:10.1016/j.mcat.2023, 113 114). easy availability, is environmentally 10.1039/D2RE.00408A).
The use of Pd membrane electrodes can native to conventional vapor compres- Selective oxidation of Allyl- friendly and stable and recyclable. (Ind.
overcome the above problems by physi- sion systems (VCS), which theoretically benzene (AB) to Cinnamalde- ETBE, and the so-called renewable End. Chem. Res., 2023; DOI: 10.1021/ Challenges in unconventional
cally separating the formation of reac- promises signifi cant improvements in hyde (C) aviation fuel, as IB can be obtained via acs.iecr.3c00600). catalysis
tive hydrogen atoms from the hydroge- both performance and energy consump- [Allylic oxidations are practiced in fermentation. Thermodynamic equili-
nation of unsaturated organic substrates. tion. This requires selective facilitation bria of various reactants and products are A. Bogaerts et al have discussed this sub-
industry, e.g., propylene to acrolein.] Modelling-aided coupling of
provided. Alumina catalysts are inhibited catalysts, conditions, memb- ject beyond the conventional “thermal”
H. Fujisuka et al have come out with by steam, so reaction under pressure ranes, and reactors for effi - catalysis. The availability of renewable
the title process as an alternative to the requires longer contact times and cata- cient H production from NH energy is opening up new ways: Plasma
established process based on benzalde- lyst volume. The effect of partial pres- 2 3 catalysis; catalysis for fl ow chemistry
hyde and acetaldehyde. BiMoO -loaded sure of water was studied, since IB is [This column has covered papers on and process intensifi cation; application
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CoFeMoO catalysts were used and a recovered from the fermentation broth. NH as H carrier and a source for of electromagnetic (EM) fi elds to modu-
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2
x
kinetic analysis was done. (Ind. Eng. [It may be noted that 5-kg of C3-C5 energy, and indeed turbines have been late catalytic activity; nanoscale gene-
Chem. Res., 2023; DOI: 10.1021/acs. alcohols are produced for every tonne developed to burn NH . There is scope ration at the catalyst interface of a strong
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iecr.3c00536). of ethanol] (Catalysis Today, 2023, to make H from NH when H is needed local EM by plasmonic effect. Plasma
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418, 1 June, 114126; DOI:10.1016/j. as a reactant.] catalyst has shown synergistic effects
Solvent-free heterogeneous cata- cattod.2023, 114126).
lytic hydrogenation of poly- N. Realpe et al have worked on mak-
esters to diols: Polylactic acid Visible light-driven sand- ing high-purity, pressurised H from
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(PLA) to 1,2-Propanediol (PD) wich-like g-C N -catalysed NH decomposition in a membrane
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oxidation to produce cumene
R. Mi et al have reported the title con- hydroperoxide (CHPO)
version of considerable commercial
importance, using Zn-modifi ed Cu cata- The producttion of phenol via air oxi-
lyst. The selectivity was 99.5% and dation of cumene and acid catalysed
reactivity was 0.65gm per gm catalyst cleavage of CHPO is practiced on
180 Chemical Weekly November 28, 2023 Chemical Weekly November 28, 2023 181
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