Tetrahedron Letters
An efficient hydrogenation of various alkenes using scrap automobile catalyst
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Mustafa Zengin , Hayriye Genc, Tuna Demirci, Mustafa Arslan, Mustafa Kucukislamoglu
Department of Chemistry, Faculty of Arts and Sciences, Sakarya University, 54187 Sakarya, Turkey
a r t i c l e i n f o
a b s t r a c t
Article history:
An efficient, easy, cheap, convenient, and safe procedure for the reduction of various alkenes to the cor-
responding alkanes is developed by using scrap automobile catalyst as an efficient hydrogenation cata-
lyst. This procedure not only gives high yields, but also allows recycling of automobile wastes as a
catalyst in organic reactions and is representative of green chemistry.
Received 13 December 2010
Revised 10 February 2011
Accepted 18 February 2011
Available online 24 February 2011
Crown Copyright Ó 2011 Published by Elsevier Ltd. All rights reserved.
Keywords:
Scrap automobile catalyst
Hydrogenation
Environmentally friendly catalyst
Catalytic hydrogenation of carbon–carbon double bonds is a
reaction of great importance in organic synthesis, and it can be
accomplished under homogeneous and heterogeneous conditions.1
Environmental concerns have led to the development of clean and
easily recycled reagents in synthetic chemistry, and the use of het-
erogeneous catalysts has received considerable attention due to
their ease of handling, enhanced reaction rates, high selectivity,
and simple work-up.2 In the last 30 years, automobile manufactur-
ers have used catalytic converters for reducing unburned hydrocar-
bons (HC), carbon monoxide (CO), and oxides of nitrogen (NOx)
from internal combustion engines.3 The active components of a
catalytic converter are platinum group metals (PGMs), especially
platinum, palladium, and rhodium, which are finely dispersed on
inert supports made of alumina.4 The total content of PGMs in
automotive converters is about 0.5–2 g/kg.5 Recycling of PGMs is
very important because it provides a supplementary source to
mining these metals, therefore, protecting the environment by lim-
iting waste disposal, managing natural resources, and reducing
electricity consumption and pollutant emissions.6 Thus, there are
numerous methods for the recovery of PGMs from catalytic con-
verters.4,7–9 On the other hand, PGMs have been used efficiently
as catalysts for the hydrogenation of unsaturated hydrocarbons.10
In continuation of our studies on the development of novel het-
erogeneous synthetic methodologies,11–14 we have developed a
process-friendly, efficient, cheap, and green procedure for the
hydrogenation of carbon–carbon double bonds catalyzed by scrap
automobile catalyst (SAC).
Catalytic converters consist of a ceramic substrate coated with
aluminum oxide (Al2O3) and other rare earth oxides, such as
CeO2, ZrO2, platinum, palladium, and rhodium which are responsi-
ble for the catalytic function.6 An used automobile catalytic con-
verter was taken from a Fiat Siena after running for 1,40,000 km.
After purification of the SAC, it was activated in an oven main-
tained at 120 °C for 12 h and found to contain 0.465% Pd and
0.040% Rh by XRF analysis. The catalytic activity of the SAC was
tested in the hydrogenation of various carbon–carbon double bond
containing compounds in THF at room temperature under a hydro-
gen atmosphere (Table 1).15
The catalyst could easily be reused after simple filtration with-
out the loss of activity over 1–4 runs. We observed chemoselectiv-
ity toward acetate under our hydrogenation conditions (Table 1,
entry 4). The ketone carbonyl groups of suberone and chalcones
(Table 1, entries 6 and 11–13) and nitro group of chalcone (Table
1, entry 13) were not reduced under these conditions.
To optimize this hydrogenation reaction, we examined the reac-
tion conditions in different solvents, such as THF, diethyl ether,
ethanol, methanol, and acetone. The solvent effect of these liquid
phase hydrogenation reactions depended on the solubility and
chemisorption of H2 on the catalyst suspended in the solvent.
The solubility and chemisorption of H2 in a nonpolar solvent is
greater then in polar solvents.16 Thus, the best results were ob-
tained in THF and diethyl ether (Table 2, entries 1and 2). We also
tested alumina and ceramic alone for their catalytic activities in
the hydrogenation of carbon–carbon double bonds and no reac-
tions were observed (Table 2, entries 9 and 10).
The lifetime of catalytic converters is limited and thus their
recycling is crucial.
In conclusion, we have developed a process-friendly, efficient,
cheap, and green procedure for the hydrogenation of carbon–
carbon double bonds catalyzed by scrap automobile catalyst
(SAC). This procedure provides high yields of products.
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Corresponding author. Tel.: +90 2642956055; fax: +90 2642955950.
0040-4039/$ - see front matter Crown Copyright Ó 2011 Published by Elsevier Ltd. All rights reserved.