Showing papers by "Indian Association for the Cultivation of Science published in 1970"
TL;DR: In this article, the solubilities of calcium iodate and copper iodate in buffered solutions of sodium lactate were investigated by a pH titration method, and thermodynamic association constants were derived for the formation of the species CaLa + at 25°, 30°, 35°, 40° and 45°C and the species CuLa +, CuLa 2 at 25.
27 citations
TL;DR: In this article, the chain transfer coefficients of the solvent and the values of δ [i.e., (2kt)1/2/kp] in solvent-monomer mixtures of various compositions were determined.
Abstract: Dimethyl sulfoxide has been used as a solvent in the polymerization of methyl methacrylate and styrene. The chain-transfer coefficients of the solvent and the values of δ [i.e., (2kt)1/2/kp] in solvent-monomer mixtures of various compositions were determined. δ was observed to be dependent on the solvent concentration in the case of methyl methacrylate but remained constant in case of styrene. The lowering of the values of δ with increasing solvent concentration in case of methyl methacrylate has been attributed to an interaction between the solvent and poly(methyl methacrylate) radical resulting in lower termination rate.
24 citations
TL;DR: The dielectric constants (e') and loss factors (e'') of phenetole, aniline and orthochloroaniline in the liquid state at different temperatures in the 3 cm and 1.5 cm microwave regions have been measured as discussed by the authors.
Abstract: The dielectric constants (e') and loss factors (e'') of phenetole, aniline and orthochloroaniline in the liquid state at different temperatures in the 3 cm and 1.5 cm microwave regions have been measured. The results have been analysed in terms of two relaxation times τ 1 and τ 2 for molecular and intramolecular orientations respectively.
24 citations
TL;DR: In this article, a new series of rare earth complexes of ethylacetoacetate (HEAA) having the composition, [Ln(EAA)2(OH)(H2O)] (where Ln stands for the lanthanides) has been prepared.
20 citations
TL;DR: In this article, the authors studied the kinetics of the reaction in aqueous HClO 4 NaClO4 media and showed that the dissociation of the first Cr(III)OH 2 bond is important in the transition state.
20 citations
TL;DR: In this paper, the cross sections for electron capture by positrons from molecular hydrogen forming positronium are calculated in the Born approximation for different incident energies, compared with those obtained using a simple peaking approximation.
19 citations
TL;DR: In this article, the properties of a series of complexes of Nickel(II) with benzoyl-thiocarbazide (HBTC), acetylthiomethieno-benzoylthiamide (HATC), nicotinoyl thiocarbazide(HNTC), 2-chloro-bensoylstioccharbazides (Cl-HBTC) and 2-hydroxy benzoy lthiamidioxide (HO-CBTC) are reported.
16 citations
TL;DR: In this article, the effect of temperature on transfer constants for different solvents in the polymerization of ethyl acrylate was observed and activation energy differences (EtrS − Ep) and frequency factors were computed.
Abstract: The effect of temperature on transfer constants for different solvents in the polymerization of ethyl acrylate was observed. Activation energy differences (EtrS − Ep) and frequency factors were computed. It is observed that high frequency factors are associated with high activation energies. Values of EtrS were calculated by an approximate method and were compared with the available data on methyl methacrylate, isobutyl methacrylate, and styrene.
15 citations
TL;DR: In this article, the acid catalysed dissociation of tetra-aquo-mono-oxalato- and tetraaquo -mono -malonato-chromium(III) ions in aqueous perchloric acid media has been investigated spectrophotometrically and activation parameters for the reactions have been evaluated.
15 citations
TL;DR: In this article, the deformation stacking fault probability α and twin stack fault probability β in cold-worked copper-antimony alloys have been obtained from peak shift and peak asymmetry measurements of the X-ray line profiles, and the fault parameter α has been found to increase in a roughly parabolic manner with increasing solute concentration.
Abstract: The deformation stacking fault probability α and twin stacking fault probability β in cold-worked copper-antimony alloys have been obtained from peak shift and peak asymmetry measurements of the X-ray line profiles, and the fault parameter α has been found to increase in a roughly parabolic manner with increasing solute concentration but the increase with increasing solute valency for fixed e / a is not clearly established. The anisotropic values of the particle size [ D e ] h k l and r. m. s. strain [ ] h k l 1/2 have been evaluated using both Fourier analysis of line shapes and integral breadth methods, and the lattice parameters have been found to vary considerably with increasing solute content. The values of the compound fault probability (1.5α+β) obtained from two independent methods are in fair agreement and the role of stacking faults in the particle size broadening is clearly seen. Particle sizes and strain values are also utilized for an estimation of dislocation density ρ in the cold-wor...
12 citations
TL;DR: In this paper, the solubilities of calcium iodate and copper iodate in buffered solutions of sodium malonate and potassium hydrogen phthalate were reported and the thermodynamic association constants for the formation of these complexes and hydration entropies of the complexes were also derived.
TL;DR: In this paper, the properties of the Schiff bases derived from 1,3-diaminopropane-2-ol and salicylaldehyde (SBH2), 3-aldehydosalicylic acid (SB′H2) and acetylacetone (SB″H2).
Abstract: The iron(III) complexes of the Schiff bases derived from 1,3-diaminopropane-2-ol and salicylaldehyde (SBH2), 3-aldehydosalicylic acid (SB′H2) and acetylacetone (SB″H2) have been isolated in the pure state and characterized. The structures of these complexes are discussed on the basis of elemental analyses, molecular weights, conductivities and magnetic susceptibilities. The Schiff bases behave as bivalent, tetradentate ligands. Room temperature (30°C) magnetic moments observed for these chelate compounds are lower than the spinonly value for high-spin d5 system.
Es wurden Eisen(III)-Komplexe mit Schiffschen Basen, die sich von 1,3-Diaminopropan-2-ol und Salicylaldehyd, 3-Aldehydosalicylsaure bzw. Acetylaceton ableiten, in reinem Zustand isoliert und charakterisiert. Ihre Struktur wird auf Grund von Elementaranalysen, Molmasse-, Leitfahigkeits- und magnetischen Messungen diskutiert. Die Schiffschen Basen fungieren als zweiwertige, vierzahnige Chelatliganden. Die magnetischen Momente der Chelate liegen bei 30°C unter dem Spinonly-Wert fur ein d5-Highspin-System.
TL;DR: In this paper, the formation of complexes of Mn 2+, Co 2+ and Ni 2+ ions with benzyl malonate ion was studied by potentiometric titrations at a temperature of 25°C at a low ionic strength and an approximate metal:ligand molarity ratio of 1 : 2.
TL;DR: In this paper, the rate of formation of the acetatopentamminechromium(III)ion from the aquopentamsmine complex in HOAcNaOAc buffer media has been investigated spectrophotometrically.
Abstract: The rate of formation of the acetatopentamminechromium(III)ion from the aquopentammine complex in HOAcNaOAc buffer media has been investigated spectrophotometrically. The results suggest that the reaction occurs by two concurrent paths one of which is independent of acetate ion while the other is first order with respect to acetate ion concentration. The values of the rate constants for both the steps and the corresponding activation parameters, ΔH≠ and ΔS≠, have been evaluated. The results are consistent with an SN1 mechanism for the acetate independent path and an SN1 IP mechanism for the acetate dependent path. Evidence for ion-pair formation is given.
Es wurde die Bildungsgeschwindigkeit von [Cr(NH3)5(OAc)]2+ (OAc = Acetat) aus [Cr(NH3)5(OH2)]3+ in Acetat-Pufferlosung untersucht. Die Reaktion lauft nach zwei Konkurrenzwegen ab, wovon einer OAc−-unabhangig ist, und der andere in bezug auf die OAc−-Konzentration nach erster Ordnung verlauft. Es wurden die jeweiligen Geschwindigkeitskonstanten und Aktivierungsgrosen, ΔH≠ und ΔS≠, ermittelt. Die OAc−-unabhangige Reaktion scheint nach SN1 abzulaufen, die andere nach einem SN1 IP Mechanismus. Ionenpaarbildung ist angezeigt.
TL;DR: Fe(III) is a 1 : 1 chelate with benzilate as mentioned in this paper, which is neutral and stable towards acid, and the equilibrium constant (K = 2.335 × 106) and change of free energy (−ΔG = 8.85 kcals) of formation are reported.
Abstract: Fe(III) forms a 1 : 1 chelate with benzilate. The equilibrium constant (K = 2.335 × 106), and change of free energy (−ΔG = 8.85 kcals.) of formation as well as the magnetic moment (μ = 6.0 BM) of the isolated solid complex have been reported. From elemental analyses and IR spectra cis-trans isomeric structures have been proposed. The complex is neutral and stable towards acid.
Eisen(III) ergibt mit Benzilsaure ein isolierbares, neutrales 1 : 1-Chelat (Gleichgewichtskonstante: K = 2,335 · 106; Anderung der freien Energie: −ΔG = 8,85 kcal; magnetisches Moment: μ = 6,0 BM). Auf Grund des IR-Spektrums werden mogliche cis/trans-isomere Strukturen vorgeschlagen.
TL;DR: In this article, the second dissociation constant of selenic acid was calculated from precise e.m.f. data over the temperature range 0° −45°C and the hydration entropies of the ion pairs were correlated with the sum of radii of the interacting ions.
TL;DR: In this article, the rate of polymerization of methyl methacrylate initiated by Fe(CIO4)3 and thiourea (TU) in tert-butyl alcohol is indepenent of [Fe(III)] and [TU] in the concentration range studied.
Abstract: The rate of polymerization Rp of methyl methacrylate initiated by Fe(CIO4)3 and thiourea (TU) in tert-butyl alcohol is indepenent of [Fe(III)] and [TU] in the concentration range studied. In contrast to Rp, the degree of polymerization DP changes markedly with the change in the initiator concentration. DP is overwhelmingly lower than is expected in a standard radical polymerization at the same Rp. Further, Rp is proportional to the square of the monomer concentration. Initiation efficiency is less than one. Independent experiments proved that in the azobisisobutyronitrile-initiated polymerization the Rp and DP are negligibly affected by [Fe(CIO4)3] or [TU], though high [TU] brings about high induction periods. The results of Fe(III)-TU-initiated polymerization have been interpreted in terms of the predominant termination of polymer radicals by primary radicals.
TL;DR: In this article, the kinetics of formation of chromium(III)-EDTA complexes in the reaction of trisacetyl-acetonato (ChIII) and tris(biguanide) ion with EDTA in alkaline media (pH ∼ 7.4-9) have been investigated spectrophotometrically.
TL;DR: In this article, the proton dissociation constants of 4-methyl phthalic acid and the stabilities of the 1 : 1 complexes of bivalent copper, nickel and cadmium ions with 4-ethyl phthalate ion were determined at constant ionic strength at 30 ± 0·1°C.
TL;DR: The rate of formation of Cr(III)-EDTA complexes from Cr(C2O4) and EDTA at pH ca. 8-9.5 has been determined spectrophotometrically as mentioned in this paper.
Abstract: The rate of formation of Cr(III)-EDTA complexes from Cr(C2O4) and EDTA at pH ca. 8–9.5 has been determined spectrophotometrically. From the observed dependence of the rate on pH and EDTA concentration a probable mechanism has been suggested for the overall change involving two concurrent paths; corresponding δH≠ and δS≠ values have also been determined. An increase in ionic strength has been found to increase the overall rate as well as that of each individual path as is expected in a reaction between ions of the same charge type.
Es wurde die Bildungsgeschwindigkeit von CrIII-EDTA-Komplexen aus Cr(C2O4) und EDTA bei pH ∼ 8–9,5 spektrophotometrisch bestimmt. An Hand der beobachteten Abhangigkeit der Geschwindigkeit vom pH-Wert, der EDTA-Konzentration und der Ionenstarke wird auf einen Zweiwegemechanismus der Gesamtreaktion geschlossen, wobei die jeweiligen Aktivierungsgrosen δH* und δS* ebenfalls ermittelt wurden.
TL;DR: Using the Ornstein-Zernike distribution function, the dielectric behaviour of binary critical mixtures has been investigated in this article, where the local field has been found to reduce to that of Debye's formula giving rise to the sharp increase in ∈ 1 as T approaches T c.
TL;DR: In this paper, the equilibrium constants for the stepwise dissociation of trisoxinato-chromium(II1) in 50 per cent (v/v) aqueous-alcoholic acidic medium have been evaluated from pH measurements using BJERRUM's method.
Abstract: The equilibrium constants for the stepwise dissociation of tris-oxinato-chromium(II1) in 50 per cent (v/v) aqueous-alcoholic acidic medium have been evaluated from pH measurements using BJERRUM's method. Even down to a pH ca. 1.9 no perceptible dissociation beyond the stage of the mono-oxinato complex takes place; hence only the equilibrium constants for the first two stages, namely tris- to bis- and bis- to mono-, could be evaluated by this method. At 35°C (μ, 0.1) the values are
where LH = oxine (8-quinolinol), C9H7NO.
Es wurden die Gleichgewichtskonstanten der stufenweisen Dissoziation von Chrom(II1)-tris-oxinat in saurer 50 vol.-proz. Alkohol- Wasser-Losung nach der BJERRUM-Methode ermittelt. Da auch bis herunter zu pH ≈ 1,9 keine weitere Disso-ziation als bis zum Mono-oxinatokomplex erfolgt, konnten nach dieser Methode K′ und K″ der beiden ersten Dissoziationsstufen bestimmt werden (Daten s. “Abstract”).
TL;DR: In this article, the theoretical expressions of magnetic anisotropy and mean susceptibility with the experimental values in the temperature range 90 to 300 °K, consistently with available optical absorption data and g-values.
Abstract: Investigations are made to explain the nature of ligand field of Cu(II) complexes in copper bisacetylacetonate and calcium copper acetate hexahydrate having square planar coordination with the neighbouring oxygens, on the basis of the ligand field theory and attempts are made to fit the theoretical expressions of magnetic anisotropy and mean susceptibility with the experimental values in the temperature range 90 to 300 °K, consistently with available optical absorption data and g-values.
Untersuchungen wurden durchgefuhrt, um die Natur des Ligandenfeldes von Cu(II)-Komplexen in Kupferdiazetylazetonat und Kalzium-Kupferazetathexahydrat mit quadratisch ebener Koordination mit benachbartem Sauerstoff auf der Basis der Ligandenfeldtheorie zu erklaren, und es wurden Versuche gemacht, die theoretischen Ausdrucke der magnetischen Anisotropie und der mittleren Suszeptibilitat mit experimentellen Werten im Temperaturbereich 90 bis 300 °K konsistent an verfugbare optische Absorptions- und g-Werte anzupassen.
TL;DR: In this paper, a macrocyclic ketone was found to be a weak initiator of vinyl polymerization and anhydrous zinc chloride strongly promoted this to form a novel initiating system.
Abstract: Dihydrocivetone, a macrocyclic ketone, has been found to be a weak initiator of vinyl polymerization. Anhydrous zinc chloride strongly promotes this to form a novel initiating system. Monomers tried successfully are methyl methacrylate, acrylonitrile and α-methylstyrene. The characteristic feature of polymerization of α-methylstyrene differs greatly from those of other monomers and those have been discussed and compared.
TL;DR: In this paper, it was shown that there is an almost universal discrepancy between the observed thermal magnetic behaviours, particularly the anisotropy and those theoretically predicted on the assumption that the ligand fields are independent of temperature.
Abstract: Paramagnetic behaviours of the salts of the iron group depend upon the asymmetric ligand fields acting upon the central paramagnetic ion, as also upon the structure and packing of the crystal lattice. A general picture of the energy levels of the paramagnetic ions is, available from the ligand field theory, based upon the coordinated data on X-ray structure, magnetic susceptibility and anisotropy, e.p.r and optical absorption spectra. When all these facts have been taken into account it is observed that there is an almost universal discrepancy between the observed thermal magnetic behaviours, particularly the anisotropy and those theoretically predicted on the assumption that the ligand fields are independent of temperature. The discrepancy cannot usually be covered by the change in the fields due to normal thermal expansion of the lattice. It is pointed out that these may be occasionally due to electric dipole ordering in the crystals at certain temperatures but more generally due to continuous ...