Sugunan, S; Binitha, N N(Journal of Applied Polymer Science,Wiley InterScience, March 16, 2007)
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Abstract:
In situ polymerization of aniline is done
inside the pillared clay matrix. The nonswellable pillared
clay confined matrix allows efficient polymerization that
leads to nanofibrous morphology. As a result high polymer
order and crystallinity is attained and is evident from
XRD patterns. The strong interaction between the clay
layers and polyaniline (PANI) is understood from FTIR and DRS spectra. Additionally these analytical results suggest that the prepared PANI is in the doped state. The
PANI/pillared clay nanocomposite formation gives additional
thermal stability to the polymer backbone and is clear from the DTG curves.
Girish Kumar,K; Saji John,Konnully; Remalakshmy,Poduval(Department of Applied Chemistry, April 2, 2005)
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Abstract:
A set of six new polystyrene anchored metal
complexes have been synthesized by the reaction of the
metal salt with the polystyrene anchored Schiff base of
vanillin. These complexes were characterized by elemental
analyses, Fourier transform infrared spectroscopy, diffuse
reflectance studies, thermal studies, and magnetic susceptibility
measurements. The elemental analyses suggest a
metal : ligand ratio of 1 : 2. The ligand is unidentate and
coordinates through the azomethine nitrogen. The Mn(II),
Fe(III), Co(II), Ni(II), and Cu(II) complexes are all paramagnetic
while Zn(II) is diamagnetic. The Cu(II) complex is
assigned a square planar structure, while Zn(II) is assigned
a tetrahedral structure and Mn(II), Fe(III), Co(II), and Ni(II)
are all assigned octahedral geometry. The thermal analyses
were done on the ligand and its complexes to reveal their
stability. Further, the application of the Schiff base as a
chelating resin in ion removal studies was investigated. The
polystyrene anchored Schiff base gave 96% efficiency in the
removal of Ni(II) from a 20-ppm solution in 15 min, without
any interference from ions such as Mn(II), Co(II), Fe(III),
Cu(II), Zn(II), U(VI), Na , K , NH4
, Ca2 , Cl , Br , NO3
,
NO2
,and CH3CO2
. The major advantage is that the removal
is achieved without altering the pH.
Transition metal-loaded (3%) nanocrystalline sulfated titania (ST) powders are prepared using the sol–gel technique. Anatase is found as the active phase in all the samples. Sulfate ion impregnation decreases the crystallite size and stabilizes the anatase phase of TiO2. Acidity of the samples is found to increase by the incorporation of sulfate ion and also by the modification by transition metal ions. All the prepared catalysts are found stable up to 700 °C.
Prathapachandra Kurup, M R; Alex, Punnoose; Manoj, E(Elsevier, October 17, 2008)
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Abstract:
Ten new copper(II) complexes of five potential bisthiocarbohydrazone and biscarbohydrazone ligands
were synthesized and physico-chemically characterized. The spectral and magnetic studies of compounds
are consistent with the formation of asymmetric di-, tri- or tetranuclear copper(II) complexes of deprotonated
forms of respective ligands. The variable temperature magnetic susceptibility measurements of all
complexes showantiferromagnetic interactions between the Cu(II) centers, in agreement with very broad
powder EPR spectra. However, frozen solution EPR spectral studies are found in contradiction with the
solid-state magnetic studies and indicate that the complexes are not very stable in solutions; the possible
fragmentations of complexes are found in agreement with MALDI MS results. The EPR spectral simulation
of most of the compounds is in agreement with the presence of two uncoupled Cu(II) species in solution.
Mohammed Yusuff, K K; Ahmed Yasir,Vakayil; Mohan Das,P N(Elsevier, International Journal of Inorganic Materials, August 12, 2001)
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Abstract:
Highly crystalline, ultra fine TiO (anatase) having high surface area has been prepared by thermal hydrolysis of titanyl sulphate 2
solution and characterized using B.E.T surface area measurements, XRD and chemical analysis. The dependence of surface area on
concentration of staffing solution, temperature of hydrolysis, duration of boiling and calcination temperature were also studied. As the
boiling temperature, duration of boiling and calcination temperature increased, the surface area of TiO formed decreased significantly. 2
On increasing calcination temperature, the crystallite size of TiO also increased and gradually the phase transformation to rutile took 2
place. The onset and completion temperatures of rutilation were 700 and 10008C, respectively
Sugunan, S; Bindhu, Jacob; Binoy,Jose(Indian Journal of Chemistry, October , 1999)
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Abstract:
The results of a detailed study of the propionylation of anisole over various medium and large pore zeolites such as H-ZSM-5, H-beta, H-Na-beta. H-mordenite. H-Y and H-RE- Y are presented and discussed. In addition, homogenous catalysts and amorphous Si02-Al2O3 are also included for comparison, The catalyst and process parameters are optimised to enhance the conversion of propionyl chloride(PC) and selectivity to 4-methoxypropiophenone(4-MOPP).
Girish Kumar,K; Remalakshmy,Poduval; Sareena, John; Pearl,Augustine(Department of Applied Chemistry, May 11, 2006)
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Abstract:
A new PVC membrane sensor, which is
highly selective towards Ni (II) ions, has been developed
using a thiophene-derivative Schiff base as the
ionophore. The best performance was exhibited by the
membrane having the composition percentage ratio of
5:3:61:31 (ionophore:NaTPB:DBP:PVC) (w=w), where
NaTPB is the anion excluder, sodium tetraphenylborate
and DBP is the plasticizing agent (dibutyl phthalate).
The membrane exhibited a good Nernstian response for
nickel ions over the concentration range of 1.0 10 1–
5.0 10 6M (limit of detection is 1.8 10 6 M) with a
slope of 29.5 1.0mV per decade of activity. It has a
fast response time of<20 s and can be used for a period
of 4 months with good reproducibility. The sensor is
suitable for use in aqueous solutions of a wide pH range
of 3.2–7.9. The sensor shows high selectivity to nickel
ions over a large number of mono-, bi- and trivalent
cations. It has been successfully used as an indicator
electrode in the potentiometric titration of nickel ions
against EDTA and also for direct determination of
nickel content in real samples – wastewater samples
from electroplating industries and Indian chocolates.
Girish Kumar,K; Remalakshmy,Poduval; Sareena, John; Pearl,Augustine(Departmenrt of Applied Chemistry, May 11, 2006)
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Abstract:
A new PVC membrane sensor, which is
highly selective towards Ni (II) ions, has been developed
using a thiophene-derivative Schiff base as the
ionophore. The best performance was exhibited by the
membrane having the composition percentage ratio of
5:3:61:31 (ionophore:NaTPB:DBP:PVC) (w=w), where
NaTPB is the anion excluder, sodium tetraphenylborate
and DBP is the plasticizing agent (dibutyl phthalate).
The membrane exhibited a good Nernstian response for
nickel ions over the concentration range of 1.0 10 1–
5.0 10 6M (limit of detection is 1.8 10 6 M) with a
slope of 29.5 1.0mV per decade of activity. It has a
fast response time of<20 s and can be used for a period
of 4 months with good reproducibility. The sensor is
suitable for use in aqueous solutions of a wide pH range
of 3.2–7.9. The sensor shows high selectivity to nickel
ions over a large number of mono-, bi- and trivalent
cations. It has been successfully used as an indicator
electrode in the potentiometric titration of nickel ions
against EDTA and also for direct determination of
nickel content in real samples – wastewater samples
from electroplating industries and Indian chocolates.
Girish Kumar,K; Pearl,Augustine; Sareena, John; Beena,Saraswathyamma(Department of Applied Chemistry, June 12, 2006)
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Abstract:
new PVC membrane ion selective electrode which is highly selective towards Ni(II) ions was constructed using a
Schiff base containing a binaphthyl moiety as the ionophore. The sensor exhibited a good Nernstian response for nickel
ions over the concentration range 1.0 × 10–1 – 5.0 × 10–6 M with a lower limit of detection of 1.3 × 10–6 M. It has a fast
response time and can be used for a period of 4 months with a good reproducibility. The sensor is suitable for use in
aqueous solutions in a wide pH range of 3.6 – 7.4 and works satisfactorily in the presence of 25% (v/v) methanol or
ethanol. The sensor shows high selectivity to nickel ions over a wide variety of cations. It has been successfully used as
an indicator electrode in the potentiometric titration of nickel ions against EDTA and also for the direct determination of
nickel content in real samples: effluent samples, chocolates and hydrogenated oils.
PVC supported liquid membrane and carbon paste potentiometric sensors incorporating an Mn(III)-porphyrin
complex as a neutral host molecule were developed for the determination of paracetamol. The measurements were
carried out in solution at pH 5.5. Under such conditions paracetamol exists as a neutral molecule. The mechanism of
molecular recognition between the Mn(III)-porphyrin and paracetamol, leading to potentiometric signal generation,
is discussed.The sensitivity and selectivity toward paracetamol of carbon paste and polymeric liquid membrane electrodes
incorporating an Mn(III)-porphyrin host were compared. The applicability of these sensors to the direct
determination of paracetamol was checked by performing a recovery test in human plasma.
Sreekumar, K; Rani, Joseph; Pramitha, V; Sudha Kartha, C(Indian Academy of Sciences, December , 2010)
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Abstract:
Plane-wave transmission gratings were stored in the same location of silver-
doped photopolymer ¯lm using peristrophic multiplexing techniques. Constant and vari-
able exposure scheduling methods were adopted for storing gratings in the ¯lm using
He{Ne laser (632.8 nm). The role of recording geometry on the dynamic range of the ma-
terial was studied by comparing the results obtained from both techniques. Peristrophic
multiplexing with rotation of the ¯lm in a plane normal to the bisector of the incident
beams resulted in better homogenization of di®raction e±ciencies and larger M/# value.
Girish Kumar,K; Saji John,Konnully(Department of Applied Chemistry, August 1, 2006)
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Abstract:
Salicylaldehyde Schiff base of amino-methylated
polystyrene has been developed as a novel reagent for the removal
of Fe(III) from solutions. The selectivity of the metal
ion uptake over a wide range of different concentrations of
metal ion, effect of pH, ligand concentration and the influence
of other foreign ions were studied. A very good selectivity
was achieved for the removal of the ion. It was found
that 0.01 g of the ligand was sufficient to achieve about 96%
removal of the metal ion in terms of concentration (ppm)
from a 30 ppm solution in acidic pH.
A new photopolymerizable recording media is introduced based on poly
(vinyl alcohol) and vinyl acetate sensitized with methylene blue. It is observed
that this MBPVA/VAc system can be reused a number of times without
significant decrease in diffraction efficiency. The PVA-VAc ratio was optimized
at 2:1. Diffraction efcienc4y of 6.3% was obtained without any fixing at a dye
concentration of 9.3 x 10- mol/l at an exposure of 750mJ/cm2. The material is
attractive on account of its reusability.
A new photopolymerizable recording media is introduced based on poly
(vinyl alcohol) and vinyl acetate sensitized with methylene blue. It is observed
that this MBPVA/VAc system can be reused a number of times without
significant decrease in diffraction . The PVA-VAc ratio was optimized
at 2:1. Diffraction efficiency of 6.3% was obtained without any fixing at a dye
concentration of 9.3 10 4 mol/l at an exposure of 750 mJ/cm2. The material is
attractive on account of its reusability.
Mohammed Yusuff, K K; Pearly Sebastian, Chittilappilly; Sridevi, N(Elsevier,Journal of Molecular Catalysis A: Chemical 286 (2008) 92–97, February 5, 2008)
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Abstract:
Zeolite Y-encapsulated ruthenium(III) complexes of Schiff bases derived from 3-hydroxyquinoxaline-2-carboxaldehyde and 1,2-
phenylenediamine, 2-aminophenol, or 2-aminobenzimidazole (RuYqpd, RuYqap and RuYqab, respectively) and the Schiff bases derived from
salicylaldehyde and 1,2-phenylenediamine, 2-aminophenol, or 2-aminobenzimidazole (RuYsalpd, RuYsalap and RuYsalab, respectively) have
been prepared and characterized. These complexes, except RuYqpd, catalyze catechol oxidation by H2O2 selectively to 1,2,4-trihydroxybenzene.
RuYqpd is inactive. A comparative study of the initial rates and percentage conversion of the reaction was done in all cases. Turn over frequency
of the catalysts was also calculated. The catalytic activity of the complexes is in the order RuYqap > RuYqab for quinoxaline-based complexes and
RuYsalap > RuYsalpd > RuYsalab for salicylidene-based complexes. The reaction is believed to proceed through the formation of a Ru(V) species.
Sugunan, S; Benny, Thomas(Indian Journal of Chemistry, February , 1995)
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Abstract:
The Setschenow parameter and thermodynamic
parameters of transfer of 2- and 4- hydroxybenzoic acids
from water to salt solutions have been reported. The data
have been rationalised by considering the structure
breaking effects of the ions of the salts, the localized
hydrolysis model, the internal pressure theory and the
theory of water structure due to Symons.
The Setschenow parameter and thermodynamic parameters of transfer of 2-, 3-, and 4-methylbenzoic acids
from water to salt solutions have been reported. The data have been rationalized by considering the structure breaking
effects of the ions of the salts, the localized hydrolysis model, and the internal pressure theory.
Sugunan, S; Benny, Thomas(Journal of Solution Chemistry, 1994)
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Abstract:
The Setschenow parameter and thermodynamic parameters of transfer of
2-, 3- and 4-fluorobenzoic acid from water to salt solution are reported.
The data have been rationalized by considering the structure breaking effects of the ions of the salts, the localized hydrolysis model and the internal
pressure theory.