Jalaja, Malayan J; Dr.Sugunan, S(Cochin University of Science and Technology, December , 1994)
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Abstract:
The rare earths have provided fascinating field
for chemists confronted with problems of their separation
and purification. The rare earths become available in
relatively pure form in recent years due to the development
of efficient separation methods, largely as a byproduct of
the atomic energy programmes of various countries. The
rare earths often called lanthanides from La (Z=57) to Lu
(Z=7l) display subtle variation of properties through the
series, while the differences become appreciable for the
elements that are farther apart.
Description:
Department of
Applied Chemistry, Cochin University of Science and
Technology
Ramankutty, C G; Dr.Sugunan, S(Cochin University of Science & Technology, November , 2000)
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Abstract:
The present study describes the surface properties and catalytic activities of
ferrospinels containing Co, Ni and Cu prepared by the low temperature route. Various
physico-chemical methods have been adopted to characterise the systems. The reactions
carried out are the Friedel-Crafts benzoylation of aromatics and the cyclohexanol
decomposition. We have attempted the sulphate modification of the ferrites and have
studied the surface and catalytic properties of the sulphated analogues.The work is presented in six chapters, the last chapter giving the summary and
conclusions of the results presented earlier. Our samples prove as potential catalysts for
the benzoylation of aromatics , for which truly heterogeneous catalysts are rare. Again ,
the materials show remarkable dehydration/dehydrogenation activities during
cyclohexanol decomposition. There is plenty of scope for research in this field, especially
in the development of environmentally benign catalysts for acylation reactions.
Description:
Department of Applied Chemistry,
Cochin University of Science and Technology
Nishamol,Kanat; Sugunan, S(Department of applied chemistry, 2002)
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Abstract:
In recent years considerable advances have been achieved in the study of the surface structure and mechanism of action of environmentally benign heterogeneous catalysts. The study entitled as surface properties and catalytic activity of manganese ferrospinels. In the present study we have prepared manganese ferrospinels of general formula Mn(1-x)BxFe2O4 via low temperature controlled co-precipation method. The study employed low temperature co-precipitation method for the preparation ofMn(1-x)BxFe2O4 specimens, where B is a metal cation such as Cr,Co, Ni,Cu and Zn. The catalytic activities of the systems were investigated for liquid-phase benzoylation of aromatic compounds and phenol hydroxylation and for vapour-phase reactions such as aniline alkylation, phenol methylation and ODH of ethylbenzene. The different series of manganese ferrites are proved to be excellent catalysts for various industrially important reactions such as Friedel-crafts benzoylation of aromatic compounds, methylation of aniline and phenol, hydroxylation of phenol and oxidative dehydrogenation of ethylbenzene. Due to the tightening of the environmental regulations, production of diphenols from phenol hydroxylation and reduction of phenolic pollutants in waste waters using these catalysts can be a promising approach because it demands only simple techniques and produce little environmental pollution.
Renuka, N K; Dr.Sugunan, S(Cochin University of Science & Technology, November , 2000)
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Abstract:
An investigation on the physical and chemical characterisation of rare earth oxide
supported vanadia is attempted in the present study. La2O3, Sm2O3 and DY2O3 serve the
purpose of supports. Supported catalysts were prepared and characterised using various
physico chemical techniques. A detailed investigation of acid base properties is also
carried out. The nature of interaction of vanadia with lanthanide oxide is discussed and
the effect of vanadia loading on the activity of the systems towards reactions of industrial
importance is explored.
Description:
Department of Applied Chemistry,
Cochin University of Science and Technology
Vijayakumar, K P; Dr.Purushothaman, C(Cochin University of Science and Technology, May 28, 1984)
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Abstract:
The thesis aims to present the results of experimental investigations on the changes of optical properties of metallic thin films due to heating. The parameters which are measured are reflectivity, refractive indices and the ellipsometric quantities V and A . The materials used in the studies are metals like Silver, Aluminium and Copper. By applying the optical method the interdiffusion taking place in multilayer
‘films of Aluminium and Silver has also been studied. Special interest has been taken to reveal the mechanisms of the hillock growth and surface roughness caused by heating and their relation with the stress in the film
Description:
Department of Physics, Cochin University of Science and Technology
Raghavan, Lisha; Prof. (Dr.) M. R. Anantharaman(Cochin University of Science and Technology, August 9, 2015)
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Abstract:
Magnetism and magnetic materials have been playing a lead role in the day to day life of human beings. The human kind owes its gratitude to the ‘lodestone’ meaning ‘leading stone’ which lead to the discovery of nations and the onset of modern civilizations. If it was William Gilbert, who first stated that ‘earth was a giant magnet’, then it was the turn of Faraday who correlated electricity and magnetism. Magnetic materials find innumerable applications in the form of inductors, read and write heads, motors, storage devices, magnetic resonance imaging and fusion reactors. Now the industry of magnetic materials has almost surpassed the semiconductor industry and this speaks volumes about its importance. Extensive research is being carried out by scientists and engineers to remove obsolescence and invent new devices. Though magnetism can be categorized based on the response of an applied magnetic field in to diamagnetic, paramagnetic, ferromagnetic, ferrimagnetic and antiferromagnetic; it is ferrimagnetic, ferromagnetic and antiferromagnetic materials which have potential applications. The present thesis focusses on these materials, their composite structures and different ways and means to modify their properties for useful applications.
Lisha, Raghavan; Dr M. R. Anantharaman(Cochin University of Science and Technology, June 30, 2016)
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Abstract:
Magnetism and magnetic materials have been playing a lead role in the day to day life of human beings. The human kind owes its gratitude to the ‘lodestone’ meaning ‘leading stone’ which lead to the discovery of nations and the onset of modern civilizations. If it was William Gilbert, who first stated that ‘earth was a giant magnet’, then it was the turn of Faraday who correlated electricity and magnetism. Magnetic materials find innumerable applications in the form of inductors, read and write heads, motors, storage devices, magnetic resonance imaging and fusion reactors. Now the industry of magnetic materials has almost surpassed the semiconductor industry and this speaks volumes about its importance. Extensive research is being carried out by scientists and engineers to remove obsolescence and invent new devices. Though magnetism can be categorized based on the response of an applied magnetic field in to diamagnetic, paramagnetic, ferromagnetic, ferrimagnetic and antiferromagnetic; it is ferrimagnetic, ferromagnetic and antiferromagnetic materials which have potential applications. The present thesis focusses on these materials, their composite structures and different ways and means to modify their properties for useful applications.
In the past, metals like Fe, Ni and Co were sought after for various applications though iron was in the forefront because of its cost effectiveness and abundance. Later, alloys based on Fe and Ni were increasingly employed. They were used in magnetic heads and in inductors. Ferrites entered the arena and subsequently most of the newer applications were based on ferrites, a ferrimagnetic material, whose composition can be tuned to tailor the magnetic properties. In the late 1950s a new class of magnetic material emerged on the magnetic horizon and they were fondly known as metallic glasses. They are well known for their soft magnetic properties. They were synthesized in the form of melt spun ribbons and are amorphous in nature and they are projected to replace the crystalline counterparts.
Arun,V; Dr.Mohammed Yusuff,K K(Cochin University of Science & Technology, June , 2009)
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Abstract:
The thesis deals with studies on the synthesis, characterisation and catalytic
applications of some new transition metal complexes of the Schiff bases derived from 3-hydroxyquinoxaline 2-carboxaldehyde.. Schiff bases which are considered as ‘privileged ligands’ have the ability to stabilize different metals in different oxidation states and thus regulate the performance of metals in a large variety of catalytic transformations. The
catalytic activity of the Schiff base complexes is highly dependant on the environment about
the metal center and their conformational flexibility. Therefore it is to be expected that the
introduction of bulky substituents near the coordination sites might lead to low symmetry complexes with enhanced catalytic properties. With this view new transition metal
complexes of Schiff bases derived from 3-hydroxyquinoxaline-2-carboxaldehyde have been
synthesised. These Schiff bases have more basic donor nitrogen atoms and the presence of
the quinoxaline ring may be presumed to build a favourable topography and electronic
environment in the immediate coordination sphere of the metal. The aldehyde was condensed
with amines 1,8-diaminonaphthalene, 2,3-diaminomaleonitrile, 1,2-diaminocyclohexane,
2-aminophenol and 4-aminoantipyrine to give the respective Schiff bases. The oxovanadium(IV), copper(II) and ruthenium(II)complexes of these Schiff bases were synthesised and characterised.
All the oxovanadium(IV) complexes have binuclear structure with a square pyramidal geometry.
Ruthenium and copper form mononuclear complexes with the Schiff base derived from 4-
aminoantipyrine while binuclear square planar complexes are formed with the other Schiff
bases. The catalytic activity of the copper complexes was evaluated in the hydroxylation of
phenol with hydrogen peroxide as oxidant. Catechol and hydroquinone are the major products. Catalytic properties of the oxovanadium(IV) complexes were evaluated in the
oxidation of cyclohexene with hydrogen peroxide as the oxidant. Here allylic oxidation
products rather than epoxides are formed as the major products. The ruthenium(II)
complexes are found to be effective catalysts for the hydrogenation of benzene and toluene.
The kinetics of hydrogenation was studied and a suitable mechanism has been proposed.
Description:
Department of Applied Chemistry, Cochin
University of Science and Technology
Arun, Aravind; Dr.Jayaraj, M K(Cochin University of Science And Technology, October 18, 2012)
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Abstract:
The objective of the present study is the formation of single phase
Zn1−xTMxO thin films by PLD and increase the solubility limit of TM
dopants. The TM doped ZnO nanostructures were also grown by hydrothermal
method. The structural and morphological variation of ZnO:TM thin
films and nanostructures with TM doping concentration is also investigated.
The origin and enhancement of ferromagnetism in single phase Zn1−xTMxO
thin films and nanostructures using spectroscopic techniques were also studied.
The dependence of ablation parameters on the structural and optical
properties of ZnO thin films were studied
Description:
Department of Physics
Cochin University of Science and Technology
Sameera ., S; Prabhakar Rao, P.(Cochin University of Science and Technology, October 16, 2015)
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Abstract:
Research in the fields of ceramic pigments is oriented towards the enlargement of the chromatic set of colors together with a replacement for more expensive and less stable organic pigments. Novel non-toxic inorganic pigments have been required to answer environmental laws to remove elements like lead, chromium, cobalt entering in the composition of usual pigments widely used in paints and plastics. Yellow is particularly an important color in the pigment industry and consumption of yellow exceeds that of any other colored pigments. Apart from this, high infrared reflective pigments are now in great demand for usage in coatings, cement pavements, automotives and camouflage applications. They not only impart color to an object, but also reflect the invisible heat from the object to minimize heat build–up, when exposed to solar radiation. With this in view, the present work aims at developing new functional yellow pigments for these applications. A series of IR reflecting yellow pigments have been synthesized and analyzed for their crystalline structure, morphological, composition and optical characteristics, coloring and energy saving applications
Saravanan, S; Dr.Anantharaman, M R; Dr.Venkatachalam, S(Cochin University of Science & Technology, November , 2003)
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Abstract:
In this work polymers belonging to polyaniline and polyaniline doped
with camphor sulphonic acid are synthesised. Cobalt phthalocyanine is an
interesting candidate belonging to the tetramers. Studies on the composites
containing cobalt phthalocyanine tetramer and polyaniline doped with camphor
sulphonic acid for various concentration are also undertaken in order to understand
the mechanism. RF plasma polymerised aniline and furfural are prepared. The
structural and electrical properties are evaluated. The bombardment of swift heavy
ions of these films are carried out and the effect of irradiation on their properties is
also investigated.
Description:
Department of Physics,
Cochin University of Science and Technology
Chandini,R Nayar; Prathapachandra Kurup, M R(Department of Applied Chemistry, 2002)
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Abstract:
Coordination chemistry of schiff bases is of considerable interest due to their various magnetic, catalytic and biological applications. Here it describes the spectral characterization of schiff bases and its Mn (II), Cu (II) and Ni (II) complexes. Then synthesis and spectral characterization of Zn (II), Cd (II) and Co (II) complexes of schiff base derived from 3-Formylsalicilic Acid and 1,3-diaminopropane. Then it discusses the synthesis and spectral studies of Copper (II) complexes of 2-Hydroxyacetophenone N-phenyl semicarbazone. Finally it discusses the synthesis and spectral characterization of Co (III) complexes of salicylaldehyde N-phenyl semicarbazone. The preparation and characterization of Cobalt (III) complexes of salicylaldehyde, N-phenylthiosemicarbazone containing hetrocyclic bases phenalthroline and bipyridine. Thiocyanate, azide and perchlorate ions act as coligands. Elemental analysis suggests +3 state for Cobalt. HNMR, IR and UV-visible spectra characterize the complexes.