Upload
bvk1976
View
221
Download
0
Embed Size (px)
Citation preview
8/3/2019 Clay Catalysts in Organic Synthesis
1/21
Presentation for Internal Project Review
byDr. B.Vijayakumar
Department of ChemistryVel Tech High Tech Dr.Rangarajan Dr.Sakunthala Engineering College
Avadi, Chennai-600 062.
Studies on Synthesis of Organic Compoundshaving Commercial Application by Green
Chemical Methods
22-01-2012
8/3/2019 Clay Catalysts in Organic Synthesis
2/21
Description of the project:
In the proposed project, novel methods are to be developed to obtain
industrially important products such as -damascone, quinoline
derivatives, arenofurans, benzyl nicotinate, etc. For example,
esterification of phenols with sterically hindered or long chain alcohols by
conventional methods is difficult. This can be achieved in presence of
eco-friendly catalysts, particularly clays, in presence of solvents or under
solvent-free conditions.
In the present proposal, Indian clays will be modified systematically using
dilute solutions of mineral and/or organic acids, and metal salts at
different temperatures and time intervals. Further, several ion exchanged
and clay supported catalysts will be prepared using various reagents such
as heteropoly acids, metal salts, etc. to obtain them in desired acidity.
22-01-2012
8/3/2019 Clay Catalysts in Organic Synthesis
3/21
Modification of clays and their applications
Cation Exchanged Clays(Brnsted acid Catalysts)
Pillared Clays(Lewis acid Catalysts)
Acid Activated Clays(Both Lewis & Brnsted)
Surfactant Modified Clay
(Adsorbents)
Clay supported Reagents(Redox catalysts)
Natural clay
Vijayakumar, B. Clay Catalysts in Organic Synthesis (Synlett Spotlight 81) Synlett
2, 2004, 388-389.
Clays are layered hydrous aluminosilicates composed of tetrahedral silicate
and octahedral aluminate sheets.
22-01-2012
8/3/2019 Clay Catalysts in Organic Synthesis
4/21
22-01-2012
8/3/2019 Clay Catalysts in Organic Synthesis
5/21
Simple representation of clay
22-01-2012
8/3/2019 Clay Catalysts in Organic Synthesis
6/21
WATERMOLECULESANDCATIONS
Smectite (2:1)
22-01-2012
8/3/2019 Clay Catalysts in Organic Synthesis
7/21
Advantages of clay catalysts
Naturally available Cheap/Economic
Easy to modify
Easy to handle
Possess both Lewis and Brnstedacidity
Acidity can be controlled
Reusable
Eco-friendly
22-01-2012
8/3/2019 Clay Catalysts in Organic Synthesis
8/21
1. to prepare indigenous smectite clays (acid treated, exchanged, and
supported) with different acidities.
2. to make a systematic study of the relationship between properties of
catalysts and their catalytic activities.
3. to explore and optimize conditions to synthesize organic compounds of
commercial importance.
4.to study the catalytic activities of the samples prepared for the
synthesis of valuable products such as esters, quinolines, imidazole
derivatives, arenofurans, quinazolinones, damascones, etc.
Objectives
22-01-2012
8/3/2019 Clay Catalysts in Organic Synthesis
9/21
Preparation of cation exchanged clays
+ Stirred at RT
Washed with distilled water
Dried at 100o
C
Clay Mn+-ion solution Mn+-exchangedcla sus ension
Mn+
-exchangedclay
Mn+
-exchanged claycatalyst
22-01-2012
8/3/2019 Clay Catalysts in Organic Synthesis
10/21
Stirred
+ at 90- 95oC
Washed with distilled water
Dried at 100
o
C
Clay Mineral acid
(Dil. Solution)
Acid-clay
sus ension
Acid activated clayAcid activatedclay catalyst
Preparation of acid activated clays
22-01-2012
8/3/2019 Clay Catalysts in Organic Synthesis
11/21
+ Stirred at RT
Solvent was removed under vacuum
Dried at 100oC
Clay Inorganic salt in
solventClay-inorganic
salt sus ension
Inorganicsalt/clay
Inorganic
salt/claycatalyst
Preparation of supported clay catalysts
22-01-2012
8/3/2019 Clay Catalysts in Organic Synthesis
12/21
(i) Synthesis of 4-substituted-2-(1-(phenylsulfonyl)-1H-pyrrolo[2,3-b]pyridin-3-yl)quinolines:
7-azaindole-3-carboxaldehyde
1 can be obtained from 7-
azaindole in two steps.
Treatment of1 with
substituted aniline 2 in
presence of clay catalysts
would form an N-aryl aldimine
intermediate, which
subsequently undergoes
[4+2]-cycloaddition with
substituted alkyne 3 followed
by aerobic dehydrogenation to
obtain quinoline derivatives.
N
N
O
SO2Ph
+ H2N
R
Catalyst
SolventR'
N
N
N
SO2Ph
R'
R
1
2
4
3
22-01-2012
8/3/2019 Clay Catalysts in Organic Synthesis
13/21
(ii) Synthesis of new heteroaryl substituted quinolines:
+ +NC CN
OH
1-NaphtholN
CHO
OCH3
R
Malononitrile
NOCH3
R
O
CN
NH2
Clay catalysts
Substituted 2-methoxy quinoline-3-carbaldehyde
Heteroaryl substituted quinolines and their derivatives exhibit
pharmacological activity such as aldosterone synthase (CYP11B2) inhibitors,
neurokinin (NK)-2/NK-3 receptor ligands, etc.,22-01-2012
8/3/2019 Clay Catalysts in Organic Synthesis
14/21
(iii) Synthesis of tetrasubstituted imidazoles:
+ +R' NH2RCHO N
N
Ph
Ph
RR'
+
OO
Ph Ph
Catalyst
CH3COO-NH4
+
Functionalized imidazoles consist of an important class of pharmacologically
active compounds that have a variety of interesting properties. Benzil,
aldehyde, amine and ammonium acetate are reacted in presence of a
catalyst to form a tetrasubstituted imidazole.
22-01-2012
8/3/2019 Clay Catalysts in Organic Synthesis
15/21
(iv) Synthesis of arenofurans:
+
NO2
R2
R1
Clay catalysts
OR2
R1
OH
RR
Arenofurans are present in many natural products that show fungicidal,
antimicrobial, insecticidal, antiproliferative, cytotoxic and antioxidant
properties. Phenol or substituted phenol or naphthol can be reacted
with nitroalkene in presence of clay catalyst to form corresponding
arenofurans by a cyclization reaction.
22-01-2012
8/3/2019 Clay Catalysts in Organic Synthesis
16/21
(v) Synthesis of 4(3H)-quinazolinones:
H2N
O
H2N
Anthranilamide
+ R-CHO
Metal salt/Clay N
NH
O
R
Quinazolinone derivatives have drawn much attention due to their broad
range of pharmacological activities, such as anticancer, antiinflammatory,
anticonvulsant and antidituric activities. Anthranilamide, aldehyde and a
metal salt supported clay catalyst will be reacted in refluxing solvent to
obtain the corresponding 4(3H)-quinazolinones.
22-01-2012
8/3/2019 Clay Catalysts in Organic Synthesis
17/21
Any literature survey done? If so, please give details:
There are reports on clays as catalysts in organic synthesis in the
literature. An important list of references is as follows.
[1] Rothenberg, G., Catalysis: Concepts and Green Applications, WILEY-VCH
Verlag GmbH & Co. KGaA, Weinheim, 2008.
[2] a) McCabe, R.W., In Inorganic Materials: Clay Chemistry, Bruce, D.W.
and O'Hare, D., Eds.; John Wiley and Sons: Chichester, 1992, 295-351.
b) Smith, K., " Solid Support and Catalyst in Organic Synthesis" Ellis
Harwood Chichester 1992. c) Augustine, R. L., "Heterogeneous Catalysis
for the Synthetic Chemist" Marcel & Dekker 1996.
[3] Balogh, M. and Laszlo, P., Organic Chemistry Using Clays, Springer:
Berlin, 1993.
[4] a) Vijayakumar, B., Clay Catalysts in Organic Synthesis, Synlett
2004,2,388. b) Nagendrappa, G., Appl. Clay Sci. 2011, 53, 106.
22-01-2012
8/3/2019 Clay Catalysts in Organic Synthesis
18/21
What is the state of the art in the area in which you proposeto take up the project:
Most of the currently conducted industrial reactions involvingpharmaceuticals, perfumes and petrochemicals make use of metals,
metal salts, metal oxides, mineral acids, metal hydroxides, microporous
zeolites, ion-exchange resins, etc.
Many reactions are performed under harsh conditions with toxic and
expensive reagents.
The organic compounds to be synthesised in the project have been
prepared using expensive and toxic reagents and are valuable products.
For example, -damascone is an important compound in perfume
industry.
22-01-2012
8/3/2019 Clay Catalysts in Organic Synthesis
19/21
Methodology to execute the project:
1. Procurement of indigenous clays and preparing acid treated, supported,
and various cation-exchanged clays,
2. Characterisation of the catalyst samples by XRD, XRF, TGA, DTA, FTIR-
DRIFTS, TPD-NH3, and BET surface area measurements,
3. Utilisation of these clay catalysts (catalytic activity) for carrying out
organic transformations,
4. Optimisation of the reaction conditions for obtaining the value added
products mentioned in the project in high yields, and
5. Synthesis of the organic compounds of interest in perfumes,
pharmaceuticals, biologically activity, etc. and characterising the organic
compounds by IR, HRMS and NMR.
22-01-2012
8/3/2019 Clay Catalysts in Organic Synthesis
20/21
9. Expected outcome of the project (Utility or application):
Outcome of the project may evince some interest from industries, which
are presently using conventional acid catalysts such as H2SO4 and HCl. An
associated socio-economic factor would be the indirect benefit, the clay-
mining activity would derive, which possibly might lead to the cost
reduction and better utilisation of industrial resources. Further, the
project has commercial application and/or patentability. The catalysts
prepared in the proposed project can be reused and the organic
compounds are used in perfumery, cosmetics, and pharmaceuticals. The
main advantage of this method is elimination of pollutant organic solvents
and the environmentally friendly character.
22-01-2012
8/3/2019 Clay Catalysts in Organic Synthesis
21/21
Thank you for your kind attention
22-01-2012