Electronic Supplementary Material (ESI) for Green Chemistry
This journal is © The Royal Society of Chemistry 2012
Direct amide bond formation from carboxylic acids and amines
using activated alumina balls as a new, convenient, clean, reusable
and low cost heterogeneous catalyst
Sabari Ghosh, Asim Bhaumik, John Mondal, Amit Mallik, Sumita Sengupta (Bandyopadhyay)
and Chhanda Mukhopadhyay*
Supplementary Information
Part 1
1. SEM image of the whole alumina ball 2. SEM images of an activated alumina ball before calcination and after calcination at 120 °C, 400 °C and 700 °C 3. Change in particle size aggregates with increase in calcination temperature of the activated alumina ball catalyst 4. EDS X‐ray spectrum of an activated alumina ball 5. Quantitative results of the EDS X‐ray spectrum of an activated alumina ball 6. Discussion on compounds 3ab and 3ac 7. Calculation of green metrics 8. Enlarged SEM images 1
page 2 page 2 page 3 page 3 page 3 page 4 page 5 page 6 Electronic Supplementary Material (ESI) for Green Chemistry
This journal is © The Royal Society of Chemistry 2012
46.90 % O
53.10 % Al
Figure S1 SEM image of the whole alumina ball; Inset: close-up SEM image of the alumina ball
before calcination. The SEM images of an activated alumina ball show aggregates of particles
and the highly porous nature of the catalyst (inset). The self-aggregated particle size before
calcination is 99-175 nm (evident by enlargement of the inset SEM image).
120 °C
no calcination
700 °C
400 °C
Figure S2 Clockwise from top left: The SEM images of an activated alumina ball before
calcination and after calcination at 120 °C, 400 °C and 700 °C. There is no visible change of the
alumina ball to the naked eye, but the close-up high resolution SEM images show that significant
morphological changes have occurred on calcinations to 120 °C, 400 °C and 700 °C (given
below).
2
Electronic Supplementary Material (ESI) for Green Chemistry
This journal is © The Royal Society of Chemistry 2012
600
400
200
0
Ca 70 00
lci 6
0
na
50
tio
00
n t 4 00
em 3
pe 200
0
ra
tu 10
re
(°C
)
Particle size
P
800
(nm)
100
0
0
0
Figure S3
S Change in
i particle size
s
aggregaates with inccrease in caalcination tem
mperature of
o the
activatedd alumina ball catalyst.
Aluminu
um
←
Oxyggen
Figure S4
S EDS X-raay spectrum of
o an activatted alumina ball.
Table S11 Quantitativ
ve results of the EDS X-rray spectrum
m of an activvated aluminna ball.
Elemeent
O
Al
Totaal
Net
Counts
C
5581
24935
Weight %
Weigght %
Errror
+/- 0.79
+/- 0.40
46.90
53.10
100.00
3
Atom %
59.84
40.16
100.00
Atom %
Errorr
+/- 1.001
+/- 0.330
Electronic Supplementary Material (ESI) for Green Chemistry
This journal is © The Royal Society of Chemistry 2012
Compouund 3ab
C
Compound
3aac
Figure S5
S Different views of thhe DFT optim
mised structture of comppound 3ab and
a 3ac shoowing
the non-eequivalent ch
hemical envvironment for the methyllene protonss in the cycloopropyl ringg. It is
interestinng to note th
hat the methyylene protonns for the cycclopropyl rinng (compounnds 3ab andd 3ac)
give twoo distinct 1H NMR siggnals, indicaating they have
h
becomee chemicallyy non-equivvalent
(Figure 7 and Figurre 8). As caan be seen from
f
the DF
FT optimisedd structures below, bothh the
cycloproppyl-CH2’s are
a directed away from the amide carbonyl
c
in case of com
mpound 3ab
b and
towards the amide carbonyl inn case of coompound 3aac. Again, out
o of the two
t
protons in a
cycloproppyl-CH2, on
ne proton is above the cyclopropyl
c
p
plane
and annother below
w this plane with
respect too the amidee carbonyl (aas designateed by the weedge bonds, Figure 8). These
T
methyylene
protons thus
t
become chemically non-equivallent. Due to the diamagnnetic anisotrropic effect of
o the
carbonyl group, onee proton eacch from the two cycloprropyl - CH2’s falls in the
t paramaggnetic
deshieldiing zone. Th
his effect is very prominnent in 3ac where there is a downfi
field cycloprropylmethylenne CHH sign
nal at δ 1.01 for two simiilar adjacentt protons. Liikewise, the other two similar
adjacent protons appear upfield at
a δ (0.77-0.772) (Figure S6).
S
OCH
H3
O
H
N
H
H
H
H
3ac
δ 0.777-0.72
→
↓
δ 1.01
O
NH
H
H
H
δ 0.69-0.61
3ab
↓
H
4
Electronic Supplementary Material (ESI) for Green Chemistry
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Figure S6 1H NMR of compounds 3ac (above) and 3ab (below) depicting the splitting of the
cyclopropyl-CH2 signals. The two adjacent CHH signals for 3ac are at δ 1.01 and δ (0.77-0.72).
Due to diamagnetic anisotropic effect of the amide carbonyl group, one proton each from the
cyclopropyl CH2’s fall in the paramagnetic deshielding zone. For compound 3ab, the
cyclopropyl-CH2’s are more chemically equivalent than 3ac and therefore come close together
rather than two sets of signals wide apart at δ (0.69-0.61).
Calculations for the synthesis of N-Phenyl-benzamide using K60 silica gel (J. W. Comerford, J.
H. Clark, D. J. Macquarrie and S. W. Breeden, Chem. Commun., 2009, 2562.)
O
NH2
K60
O
N
H
Refluxing toluene
OH
47%
Input
Benzoic acid
1.47g (12mmols)
Aniline
1.12g (12mmols)
Toluene
K60
Total
17.34g (20ml)
1.30g (50% wt)
21.23g
Output
N-Phenyl-benzamide
Organic solvent waste
(90% recovery)
K60 catalyst
1.11g
1.73g
1.30g
3.03g
Total waste
E-Factor
(3.03g waste/ 1.11g of product) = 2.73
Mass intensity
(21.23g of raw materials used/1.11g of crude product) = 19.13 (much away from ideal result)
Atom economy
[197/ (122+ 93)]×100% = 92%
Calculations for the synthesis of N-Phenyl-benzamide using activated alumina balls (our
methodology)
O
NH2
O
Alumina balls
OH
neat reaction
N
H
75%
5
Electronic Supplementary Material (ESI) for Green Chemistry
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Input
Benzoic acid
Aniline
Alumina ball catalyst
Total
Output
N-Phenyl-benzamide
Alumina ball catalyst
Total waste
1.22g (10mmols)
0.93g (10mmols)
0.22g (10% wt)
2.37g
1.48g
0.22g
0.22g
E-Factor
(0.22g waste/ 1.48g of product) = 0.15
Mass intensity
(2.37g of raw materials used/1.48g of crude product) = 1.60 (almost towards ideal result)
Atom economy
[197/ (122+ 93)]×100% = 92%
Enlarged SEM image of the alumina ball (no calcination)
6
Electronic Supplementary Material (ESI) for Green Chemistry
This journal is © The Royal Society of Chemistry 2012
Enlarged SEM image of the alumina ball (120°C)
Enlarged SEM image of the alumina ball (400°C)
7
Electronic Supplementary Material (ESI) for Green Chemistry
This journal is © The Royal Society of Chemistry 2012
Enlarged SEM image of the alumina ball (700°C)
8