Page 5 of 5
Journal Name
Catalysis Science & Technology
DOI: 1C0.O10M39M/CU5CNYI0C0A00T2IOE N
standard condition for the gram scale synthesis of acetate ester 2s in a Natural Plant Products Division, CSIRꢀInstitute of Himalayan Bioresource
Technology, Palampur ꢀ176061, H.P., India
67% yield (Scheme 4).
Fax: (+91)ꢀ1894ꢀ230ꢀ433; eꢀmail: pdas@ihbt.res.in; pdas_nbu@yahoo.com
b Academy of Scientific & Innovative Research (AcSIR), New Delhi, India.
OH
O
Me
toluene
†
Electronic supplementary information (ESI) available: Experimental
procedures, preparation and characterization of Rh@PMe3NCl catalyst
and full spectroscopy data for all compounds are provided .
C
O
t
+
CH OH +
NaO Bu
3
+
Rh@[P(Me)3n-1NCln-1 m
]
=
100 oC, 65 h
2s
+ Rh@[P(Me)3nNCln]m
H2 + HOtBu+ NaCl
1s
+
67% (on a 1 g scale)
1 a) P. G. M. Wuts and T. W. Greene, Protective Groups in Organic
Scheme 4. Gram scale synthesis of acetate ester. #The generalized form of
Rh@[P(Me)3nNCln]m has been mentioned as Rh@[P(Me)3NCl in the manuscript to
avoid confusion (detail provided in supporting information).
Synthesis,
Wiley, New York, 2nd edn., 1991; b) J. Otera,
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Functional Group Preparations, Vol. 1, 2nd ed., Wiley, New York,
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Fig 5. TEM image of Rh@PMe3NCl after six cycles of esterification
6. T. Zweifel, J. V. Naubron and H. Grutzmacher, Angew. Chem. Int. Ed.
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N. Aggarwal and P. Das, Tetrahedron Lett. 2011, 52, 4954ꢀ4956; c)
A. K. Shil, N. R. Guha, D. Sharma and P. Das, RSC Adv., 2013, 3,
13671ꢀ13676; d) S. Kumar and P. Das, New J Chem. 2013, 37, 2987ꢀ
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11. N. R. Guha, C. B. Reddy, N. Aggarwal, D. Sharma, A. K. Shil, Bandna
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In the recyclability experiment, TEM study of Rh@PMe3NCl after six
cycles of reaction showed the presence of Rh NPs in the solid matrix
(Fig. 5). Moreover, inductively coupled plasmaꢀatomic emission
spectroscopy (ICPꢀAES) analysis of the crude reaction mixture
indicated that after six cycles of reaction, only 0.336 ppm of Rh in total
was leached into the reaction mixture (supporting information).
Conclusions
In conclusion, Rh@PMe3NCl NPs as heterogeneous catalyst played a
remarkable role for CDCM esterification of benzyl and alkyl alcohols
with methanol to generate acetate esters without using any additives or
hydrogen acceptors. The process proceeded via preferential
dehydrogenative oxidation reaction of methanol in comparison to the
activated benzyl and longꢀchain aliphatic primary alcohols and resulted
into the exclusive formation of acetate esters indicating a high degree of
selectivity. The unprecedented methodology demonstrated herein is a
new findings considering basic scientific approach and could be
attractive for future implementation of the process for hydrogen
generation from methanol.
Acknowledgements
We are grateful to Director CSIRꢀIHBT for providing the necessary
facilities during the course of work. The authors thank CSIR, New
Delhi for financial support as part of XIIth Five Year Plan programme
under title ORIGIN (CSCꢀ0108). We also thank AIRF, JNUꢀNew
Delhi, for the TEM and EDX analysis, SAIF, IIT Bombay for ICPꢀAES
analysis and Mr. Piar Chand (SRF), HATS Division, CSIRꢀIHBT for
detection of formaldehyde by GC. NRG and DB thank UGC and CSIR,
New Delhi for awarding fellowships. CSIRꢀIHBT communication No.
3679.
Notes and references
This journal is © The Royal Society of Chemistry 2012
J. Name., 2012, 00, 1-3 | 5