Page 172 - CW E-Magazine (27-2-2024)

Special Report

corresponding aldehydes, and secon- DFT calculations were done. (Chem. and was recycled 20 times with a low
dary alcohols to the corresponding Eng. Sci., 2023, 282, 5 Dec., 119215; constant leaching of 3-4% per run. (Ap-
th
ketones, in very selective way. Aqueous DOI: 10.1016/j.ces.2023.119215). plied Catalysis A: General, 2023, 666,
NaBr, NaOCl at pH of around 9.5 is 25 Sep., 119392; DOI: 10.1016/j.apcata.
employed; catalytic amount of TEMPO α-Zirconium phosphate (ZP) 2023.119392).
is used. The flow approach, if required, supported Cu catalyst for
can be coupled with inline reactive selective oxidation of phenol to N-Methylation of
extraction by the formation of the carbonyl- cis-cis-muconic acid (MA) N-monomethyl amines
bisulphite adduct. Phenyl propanal was
prepared; also trifluoromethylated ox- J. He et al have reported that ZP alone Y. Saito et al have reported a con-
azole building block and a late stage gives a preferential selectivity of up to tinuous-flow N-methylation with
intermediate for the anti-HIV drug, 80% of dihydroxybenzene with cate- HCHO+H , using a heterogeneous Pd
2
maraviroc. (Org. Proc. Res. Dev., 2023; chol/hydroquinone ratio of 1.4:1. The catalysts. This works for aliphatic and
DOI: 10.1021/acs.oprd.3c00237). ZP supported Cu catalyst gives MA aromatic amines. High atom economy
by in-situ generating performic acid. is reported at ambient temperature
Dimethyl adipate (DMA) nitri- At 66% conversion of phenol, 60% and pressure. 23 examples are given.
lation to adiponitrile (AON) selectivity of MA is reported at 30°C. (Green Chem., 2023; DOI: 10.1039/
(Applied Catalysis A: General, 2023, 25 D3GC01472J).
T. Guo et al have used a series of August, 664, 119351; DOI: 10.1016/j.
NB W 10-x (x =10, 9, 7, 5 and 0) compo- apcata.2023.119351). Continuous hydrogenation of
x
site for the title gas phase conversion. Maltose (M) over Raney Ni in
Nb W gave a single pass yield of 85.2% Carbon supported polyoxo- a Trickle Bed Reactor (TBR)
9
1
at lower reaction temperature and lower metalates (POM) as recyclable
NH /DMA molar ratio. (Chem. Eng. solid acid catalysts in aqueous H. Fan et al have worked on M to Malti-
3
Sci., 2023, 281, 5 Nov, 119121; DOI:1 reactions tol (MT) and have emphasised moving
0.1016/j.ces-2023.119121). from batch to continuous reactors. In
L. Hombach et al have immobilised pursuit of this, they have used a milli-
Selective oxidative conversion phosphotungstic acid (PTA) on acti- metre-scale Raney Ni. Under optimal
of cyclohexylamine (CA) to vated carbon (AC) by equilibrium conditions, 91% conversion of M and
cyclohexanone (CH) impregnation. This PTA/AC was applied a yield of about 88% of MT is reported.
for the hydrolysis of the hemicellulose Concentrated M solution was also used.
S. Hasannia et al have reported the use xylan as an aqueous model reaction and (Ind. Eng. Chem. Res., 2023; DOI:
of Co-WO catalyst for the title conver- this selectively yielded xylose with up 10.1021/acs.iecr.3c01723).
3
sion. Under total conversion of 81% to 74% yield. The catalyst was easily
of CA the selectivity to CH was 86%. separated from the reaction system Enhanced activity of Cu/SiO
2
and Cu/ZrO catalysts in di-
2
methyl adipate (DMA) hydro-
genolysis to 1,6-hexanediol

J. Aubrecht et al have avoided the use
of CuCr O catalyst due to the pre-
2
3
sence of Cr and have worked on the
title catalysts. The method of preparing
catalysts is given, to obtain very small
and active Cu particles for Cu//SiO
2
and highly dispersed Cu phase for Cu/
ZrO . Cu/SiO catalyst was more selec-
2
2
tive for 1,6-hexanediol. (Catalysis
Today, 2023, 424, 1 Dec., 113843;
st
DOI: 10.1016/j.cattod.2022.07.011).
172 Chemical Weekly February 27, 2024

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