Browsing by Author "Dan Singh"

Now showing 1 - 8 of 8

Electrochemical synthesis and properties of poly(3-methylthiophene): Novel synthesis of poly(3-methylthiophene) with pentachlorostannate and hexachloroantimonate
(John Wiley & Sons Inc, 1999) Dan Singh; S. Dubey; B.M. Prasad; R.A. Misra
Poly(3-methylthiophene) (P3-MeT) doped with different anions were prepared electrochemically in the presence of tetraalkylammonium salts. The new poly(3-methylthiophene) SnCl5- and SbCl6- (P3-MeT SnCl5 and P3-MeT SbCl6) were prepared electrochemically using tetra-n-butylammonium pentachlorostannate and tetra-n-butylammonium hexachloroantimonate as the supporting electrolytes. The effect of current density, salt concentration, reaction temperature, and the nature of solvents on the polymer yield and polymer conductivities have been investigated. Cyclic voltammetry of poly(3-methylthiophene) has been examined at platinum electrode in 1,2-dichloroethane medium containing n-Bu4NSnCl5, Bu4NSbCl6, and Bu4NClO4 as the supporting electrolytes in the range of -1.0 to 1.7 V versus SCE in the presence and absence of 3-methylthiophene. Electrical conductivity, magnetic susceptibility measurements, and structural determination by elemental analysis and infrared studies were also made. Scanning electron microscopy revealed a globular, branched, fibrous and a spongy, fibrous morphology of poly(3-methylthiophene) SnCl5-, ClO4, and SbCl6-, respectively. The thermal analysis of the polymers was also investigated. Possible causes for the observed lower conductivity of these polymers have also been discussed.
Enzymatic synthesis and various properties of poly(catechol)
(Elsevier Science Inc, 1998) Shipra Dubey; Dan Singh; R.A. Misra
Poly(catechol) was prepared by using peroxidase as a catalyst in two types of solvent systems: an aqueous dioxane solution and a reverse micellar solution. Peroxidases derived from two sources, horseradish (HRP) and soybean (SBP), were employed as catalyst. The structure of the prepared polymer was elucidated by infrared analysis. Enzymatically prepared film of poly(catechol) at a Pt electrode was subjected to cyclic voltammetric studies in aqueous HCl medium and phosphate buffer pH 6.5. Thermal studies of the polymer were performed by thermogravimetric analysis. The iodine-labelled polymers showed low electrical conductivity in the range of 10-6 to 10-9 S cm-1. The magnetic susceptibility and surface morphological property of the polymer were also studied.; Poly(catechol) was prepared by using peroxidase as a catalyst in two types of solvent systems: an aqueous dioxane solution and a reverse micellar solution. Peroxidases derived from two sources, horseradish (HRP) and soybean (SBP), were employed as catalyst. The structure of the prepared polymer was elucidated by infrared analysis. Enzymatically prepared film of poly(catechol) at a Pt electrode was subjected to cyclic voltammetric studies in aqueous HCl medium and phosphate buffer pH 6.5. Thermal studies of the polymer were performed by thermogravimetric analysis. The iodine-labelled polymers showed low electrical conductivity in the range of 10-6 to 10-9 S cm-1. The magnetic susceptibility and surface morphological property of the polymer were also studied. Copyright (C) 1998 Elsevier Science Inc.
Estimation of suitable sowing time for chickpea (Cicer arietinum L.) genotypes in Kolhapur region of Maharashtra, India
(Enviro Media, 2016) Prudhvi Raj Vennela; Varsha Gayatonde; S.R. Shinde; Dan Singh
The present investigation on "Estimation of suitable sowing time for Chickpea (Cicerarietinum L.) genotypes in Kolhapur region of Maharashtra" was conducted with ten genotypes of chickpea, under four sowing dates viz., E, (15th October), E2 (30th October), E3 (15th November) and E4 (30th November) in Randomized Block Design, with three replications at Post Graduate Research Farm, College of Agriculture, Kolhapur during Rabi 2013-14. The recorded data was subjected to statistical and stability analysis by following the approach given by Eberhart and Russell (1966). Analysis of variance revealed significant differences for all the characters in all the environments under study. Optimum sowing, E2 (15th October) recorded higher mean values for seed yield and its components. The studied genotypes showed differential performance for all the characters. Considering the mean yield performance, the genotypes showed best performance for E2 sowing date i.e. 30th October. Whereas least performance was observed for E4 sowing date i.e. 30th November. Copyright © EM International.
Oxidation of olefins and hydrazones by anodically in situ generated manganese (III) acetate
(1999) Shipra Dubey; Dan Singh; R.A. Misra
The oxidation of olefins and hydrazones of carbonyl compounds has been performed by using in situ anodically generated milder oxidant Mn(III) acetate at Pt electrode in acetic acid. The oxidation of acyclic olefins leads to the formation of 1,2-diacetate while in the case of cyclic olefin it results in the formation of γ-lactone ring onto double bond. Further, intermolecular carbolactonization of olefins has been achieved using more reactive carboxylic acid substrate i.e. ethyl hydrogen malonate at room temperature under the similar reaction conditions. Mn(III) acetate oxidation of hydrazones of carbonyl compounds leads to its fragmentation products.
Oxidative synthesis and properties of poly(2-ethylaniline)
(1999) R.A. Misra; S. Dubey; B.M. Prasad; Dan Singh
Poly(2-ethylaniline), a π-electron conjugated conducting polymer, has been prepared under different polymerization conditions in nitrogen atmosphere. The structure of the prepared polymer has been elucidated by infrared spectra and elemental analyses. The electrochemical studies of the polymerization of 2-ethylaniline and its film at a platinum electrode have been performed in 1,2-dichloroethane using different dopants. The electrical conductivities of these polymers are found to be in the range of 10-4 to 10-7 Scm-1. Thermal studies of the polymer were carried out by thermogravimetric analysis. The DTG curves of Cl O4/- and SbCl6/- doped polymer reveal the maximum weight loss at 400 and 500°C respectively. The magnetic susceptibility of the prepared polymer shows paramagnetic behaviour. Surface morphology of the polymer film is also described.
Synthesis and characterization of poly (ortho-anisidme) using quinolinium fluorochromate (QFC) [C9H7NH(CrO3F)] as an oxidizing agent
(1999) Shipra Dubey; Dan Singh; R.A. Misra
Poly(o-anisidine) has been prepared using quinolinium fluorochromate C9H7NH[CrO3F] (QFC) as an oxidizing agent and the polymer was obtained in good yield. The detailed electrochemical studies have been performed in the presence of QFC in aqueous and non-aqueous media. TG analysis exhibited that the synthesized polymers have relatively high thermal stability. Conductivity of the polymers was found in the range of 10-9 to 10-3 Scm-1 and the magnetic susceptibility measurement show the paramagnetic behaviour. The study also include the structural elucidation and external morphological properties of the synthesized polymers.
Synthesis and Properties of Poly(o-phenylenediamine)
(PRINTS PUBLICATIONS PVT LTD, 1996) Brij Mohan Prasad; Dan Singh; Ram Achal Misra
Poly(o-phenylenediamine) has been prepared under different polymerization conditions in nitrogen atmosphere using chemical and electrochemical methods. The effect of current density, reaction temperature and the nature of solvents on polymer yields and polymer conductivities has been investigated. The cyclic voltammogram of o-phenylenediamine was examined in the range 0.0 to 1.0 V vs SCE in aqueous solution of hydrochloric acid. Morphological property of the polymer was obtained by scanning electron micrograph (SEM). These polymers are found to have electrical conductivity in the range of 10-9 to 10-7 S cm-1. Magnetic susceptibility of polymer sample was also determined.
Synthesis and Properties of Various Ring Substituted Conducting Polyanilines
(PRINTS PUBLICATIONS PVT LTD, 1996) Brij Mohan Prasad; Dan Singh; Ram Achal Misra
Electrochemical and chemical methods have been used to prepare, under nitrogen atmosphere, various ring substituted polyanilines viz.; Poly (2-bromoaniline), poly (2-chloroaniline), poly (3-chloroaniline) and poly (2-carboxyaniline). The polymerization has been carried out under different conditions of solvent, dopant and current density. The effect of current density and temperature has been examined on the yield and conductivity of poly (2-chloroaniline). The cyclic voltammetry of the oxidation of some substituted polyanilines and their formation on platinum anode were also investigated. The morphological properties of poly (2-haloaniline) was obtained using scanning electron micrograph (SEM). The polymers are found to have electrical conductivity in the range of 10-7 to 10-4 Scm-1. Magnetic susceptibility of polymers was also determined.