RSC Advances
Paper
RANEY® nickel has a good selectivity in THF for the hydroge-
nation of C]C double bonds in unsaturated ketones.
Conclusions
In this work, the selective hydrogenation of isophorone to
TMCH can be performed under RANEY® Ni under solvent-free
and solvent conditions. It was found that the THF solvent can
promote the selective hydrogenation of isophorone to TMCH.
THF can efficiently inhibit further hydrogenation of TMCH. The
conversion of isophorone is 100%, and the yield of 3,3,5-tri-
methylcyclohexanone is 98.1%. The selective hydrogenation of
unsaturated ketones was realized by using non-noble metals
instead of traditional noble metals. The method was applied to
the selective hydrogenation of isopropylidene acetone, benzy-
lidene acetone and 6-methyl-5-ene-2-heptanone. The yield of
these target products was over 97.2%. The production cost can
be reduced by using RANEY® metal instead of the noble metal
palladium. This method has good application prospects.
Fig. 7 Conversion of isophorone (black bars) and the carbon yields of
TMCH (cyan bars) and 3,3,5-trimethylcyclohexanol (white bars) as
a function of the recycling time. Reaction conditions: 1.16 g iso-
phorone, 0.05 g RANEY® Ni, 10 mL THF and 2.0 MPa H2; 298 K, 2 h.
Conflicts of interest
There are no conicts to declare.
Acknowledgements
This work was supported by Key Scientic Research Plan of
Shaanxi Provincial Education Department in 2020 (20JS013,
20JS014) and the Open Project of Shaanxi Key Laboratory of
Catalysis (No. SLGPT2019KF01-24).
Scheme 3 Selection of the hydrogenation path for different reaction
substrates.
Notes and references
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(Fig. S4†) of the methyl isobutyl ketone shows the following
peaks: 1H NMR (CDCl3-d), d: 2.3–2.31 (d, 2H), 2.13 (s, 3H), 2.09–
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1
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´
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4470 | RSC Adv., 2021, 11, 4465–4471
© 2021 The Author(s). Published by the Royal Society of Chemistry