Indian Journal of Chemistry

Sect. A: Inorganic, Bio-inorganic, Physical, Theoretical & Analytical

Total visitors: <%=showHitCnt%>      since 07-11-05

 

VOLUME 44A

NUMBER 10

OCTOBER 2005

CONTENTS

Papers

 

1979

 

Gaussian basis sets for some polyatomic two-heavy-atom hydrides

 

 

 

 

 

 

 

 

 

José M Pires & F E Jorge*

 

 

 

Gaussian basis sets have been generated with an improved generator coordinate Hartree-Fock (HF) method. These have been contracted and enriched with polarization functions. For the molecules, C2H2, C2H4, C2H6, N2H2, N2H4, H2O2, Si2H2, P2H4, and H2S2, the ground state HF total energies have been calculated. At the HF and MP2 levels, equilibrium geometries and harmonic vibrational frequencies have been calculated and compared with the corresponding experimental results and with results calculated with the 6-31G* basis sets.

 

 

1984

 

Simulation of the effect of oxalic acid and acetone on the bistable behaviour of the minimal bromate oscillator in a CSTR

 

 

 

 

 

 

C Basavaraja, V R Kulkarni*, T K Vishnuvardhan, S Mohan, Y M Iyer & G V Subba Rao

 

 

 

Simulation of the effect of oxalic acid as well as acetone on the bistable behavior of the minimal bromate oscillator in a CSTR is reported. The system is found to be bistable between certain ranges of [Br-]0. This range of values of
[Br]0 gets broadened when oxalic acid and/or acetone are additionally present in the minimal bromate oscillator.

 

 

1988

 

X-ray diffraction structures of two
isomeric decacarbonyltriosmium compounds of quinoxaline, [(
m-H)Os3(CO)10(m-1,8-h2-C8H5N2)] and [(m-H)Os3(CO)10(m-1, 2-h2-C8H5N2)]

 

 

 

 

 

 

 

 

 

  

 

Noorjahan  Begum,   Uttam  K   Das,
G   M   Golzar   Hossain,   Md.   Iqbal   Hyder   &
  Shariff   E   Kabir
*

 

 

 

Treatment of [Os3(CO)10(MeCN)2] with quinoxaline
at room temperature results in the isolation of two
isomeric clusters [(
m-H)Os3(CO)10(m-1,8-h2-C8H5N2)]  and [(m-H)Os3(CO)10(m-1,2-h2-C8H5N2)]  in 50 and 10% yields respectively.

 

  

 

 

1995

 

Homo- and hetero-binuclear complexes of a compartmental Schiff base ligand. Synthesis and characterisation

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Kamalendu   Dey*,   Saikat Sarkar,
Ranabir   Bhowmick,   Susobhan   Biswas &
Dhananjoy   Koner

 

 

 

2003

 

Synthesis and characterization of novel catalase resistant monoperoxo divanadate(V) compounds

 

 

 

 

Swapnalee Sarmah, Diganta Kalita,
Pankaj Hazarika & Nashreen S Islam
*

 

 

 

 

 

2010

 

Synthesis and characterization of coordination compounds of Cd(II), Co(II), Ni(II), Cu(II) and Zn(II) with rutin

 

 

 

 

 

 

Jingwan Kang*, Biquan Su & Xiaoquan Lu

 

 

 

 

 

2015

 

Study of electrocatalytic properties of platinum-loaded poly-ortho-aminophenol film towards methanol oxidation and hydrogen evolution

 

 

 

 

 

 

N Bahrami Panah, M G Mahjani*, M Jafarian & F Gobal

 

 

 

Platinum microparticles electrodeposited at a glassy carbon surface and within a poly-ortho-aminophenol film formed on a GC substrate have been investigated for their catalytic activity towards hydrogen evolution reaction and methanol oxidation. The effect of the deposition time of the Pt particles dispersed into GC and PoAP electrodes and of the acid anions on the hydrogen adsorption/desorption peaks as well as hydrogen evolution reaction has been studied.

 

2024

 

Thermal behaviour and spectral studies on cotton cellulose modified with phosphorus, sulphur and metals

 

 

 

 

 

 

J B Dahiya* & Sushila Rana

 

 

 

The potential flame retardancy of cellulose benzylthiophosphate (CBTP) and its metal complexes has been investigated. Results show that the activation energies of CBTP and its metal complexes for decomposition stage are in the range 31-45 kJ mol1 and are lower than that of cellulose (165.85 kJ mol1) in air atmosphere. Modified cellulose samples, when heated, give rise to high char yields. The values of DH are reduced significantly and spread over a  wide range of temperature by introducing phosphorus, sulphur and metals in cellulose.

2030

Ion-associate of arsenic(V)-salicylic acid chelate with methylene blue in toluene: Application for arsenic quantification

 

 

 

Subrata Kundu, Sujit Kumar Ghosh, Sudip Nath, Sudipa Panigrahi, Snigdhamayee Praharaj, Soumen Basu & Tarasankar Pal*

 

 

Selective detection and determination of arsenic in parts per million levels using salicylic acid and a cationic dye, methylene blue, have been carried out. Salicylic acid configures an anionic chelate with arsenic(V) and then the dye in turn forms a toluene soluble ion-associate. Using standard colour comparator chart, semi-quantitative determination of arsenic has been carried out. The method has been successfully employed for the quantification of arsenic in real samples.

Notes

 

2034

 

Structural, optical and electrical characterizations of spray deposited CdMoO4 and CdWO4 thin films

 

 

 

 

 

 

 

 

 

P K Pandey*, N S Bhave & R B Kharat

 

 

 

Cadmium molybdate and cadmium tungstate thin films have been prepared for the first time by spray pyrolysis using their ammonical solution as precursor. Growth of the films takes place by pyrolytic decomposition of the spraying precursor solution onto the preheated glass substrates.

 

 

2039

 

Kinetics and mechanism of oxidation of alcohols by butyltriphenylphosphonium dichromate

 

 

 

 

 

 

 

 

Anita Kothari, Seema Kothar & Kalyan K Banerji*

 

 

 

Butyltriphenylphosphonium dichromate oxidizes aliphatic alcohols to the corresponding carbonyl compounds. The reaction is first order in BTPPD with a second order dependence each on the alcohol and hydrogen ions. The oxidation of deuteriated ethanol and 2-propanol indicates the presence of a substantial primary kinetic isotope effect. The rate of oxidation shows excellent correlation with the polar and steric substituent constants.

 

 

2044

 

Kinetics and mechanism of oxidation of aromatic aldehydes by N-chlorosuccinimide in aqueous acetic acid

 

 

 

 

N Mathiyalagan* & R Sridharan

 

 

 

Kinetics of oxidation of aromatic aldehydes by
N-chlorosuccini­mide in the presence of HClO4 and NaCl in aqueous acetic acid medium is reported. The observed rate of oxidation is first-order with respect to [NCS], [H+] and [Cl-]. The order with respect to [aldehyde] is always zero. The rate is found to increase with decrease in the dielectric constant of the medium. Increase of ionic strength of the medium decreases the rate of oxidation. Addition of succinimide, has negligible effect on the rate of oxidation.

2048

 

Oxidation of tellurium(IV) by tetrabutylammonium tribromide

 

 

 

 

V A Kalantre & G S Gokavi*

 

 

 

The reaction between tetrabutylammonium tribromide and tellurium(IV) has been studied in 50% (v/v) acetic acid under second order conditions. The overall order of reaction is found to be two, unity each in both the reactants. The reaction is retarded by hydrogen ions due to prior protonation equilibria of the reductant. The active species of the reactants is found to be tribromide ion of the oxidant and HTeO3- of the reductant.

 

 

2051

 

Adsorption kinetics of Brij 35 at air/solution interface

 

 

Zhongni Wang*, Feng Liu , Quanxuan Zhang,
Xilian Wei, Dezhi Sun, Ganzuo Li &
Gaoyong Zhang

 

 

 

Dynamic surface tension and surface adsorption kinetics at the air/aqueous solution interface of dodecyl polyoxyethylene(23) ether have been investigated at different bulk surfactant concentrations and temperatures. Brij 35 solutions follow a mixed diffusion-activation adsorption mechanism. Results indicate that the diffusion tendency decreases with increase in the interaction between surfactant molecules while the thermo-motion of the molecules favors surface adsorption.

 

2055

 

Solvent effects on alkaline hydrolysis of
N-benzylphthalimide in mixed water-acetonitrile and mixed water-N,N-dimethylformamide

 

 

 

 

 

 

Cheong May Ye, Azhar Ariffin &
Mohammad Niyaz Khan*

 

 

 

The nucleophilic second-order rate constant for the reaction of OH- with N-benzylphthalimide (NBPT) appears to follow a reaction mechanism similar to that for reactions of OH- with phthalimide and its N-alkylphthalimides. The rate of hydrolysis reveals an insignificant contribution of water-catalysed cleavage of NBPT compared with its
hydroxide ion catalysed. The observed pseudo first-order rate constants for alkaline hydrolysis of NBPT
decrease with increase in the contents of organic cosolvents (up to 70 %, v/v) in mixed water-CH3CN and water-DMF solvents.

 

 

2060

 

A polymeric membrane ion selective electrode based on organic-inorganic composite ion exchanger for the determination of thorium(IV)

 

 

 

 

Sulekh Chandra*, Himanshu Agarwal,
Chandan Kumar Singh, Susheel Kumar Sindhu & Pankaj Kumar

 

 

 

A poly(vinyl chloride) membrane electrode based on organic-inorganic composite ion exchanger, tin(IV) tungstoselenate-pyridine, has been prepared and tested for the selective determination of thorium(IV) ions. The PVC membrane electrode comprising 16% composite ion exchanger as the electroactive phase, 50% o-dioctyl phthalate as plasticizer, 4% tetraphenyl borate as anionic excluder and 30% poly(vinyl chloride) displays a linear response to thorium(IV) ions over a wide concentration range of 1.0´10-1-8.0´10-6 M.

 

2064

 

Announcement

 

 

 

 

 

Authors for correspondence are indicated by (*)

 

Indian Journal of Chemistry

Vol. 44A, October 2005, pp. 1979-1983

 

Gaussian basis sets for some polyatomic two-heavy-atom hydrides

 

José M Pires & F E Jorge*

Received 1 June 2005; revised 2 August 2005

Gaussian basis sets have been generated with an improved generator coordinate Hartree-Fock (HF) method. These have been contracted and enriched with polarization functions. For the molecules, C2H2, C2H4, C2H6, N2H2, N2H4, H2O2, Si2H2, P2H4 and H2S2, the ground state HF total energies have been calculated using our and 6-31G* basis sets. At the HF and MP2 levels, equilibrium geometries and harmonic vibrational frequencies have been calculated and compared with the corresponding experimental results and with results calculated with the 6-31G* basis sets. At the MP2 level, significant improvements are noted in these results, and the mean absolute (percentage) deviations from experimental bond length, bond angle, and vibrational frequency are 0.008Å, 1.6°, and 2.61%, respectively.

 

 

Indian Journal of Chemistry

Vol. 44A, October 2005, pp. 1984-1987

 

Simulation of the effect of oxalic acid and acetone on the bistable behaviour of the minimal bromate oscillator in a CSTR

C Basavarajaa, V R Kulkarnia,*, T K Vishnuvardhana, S Mohanb, Y M Iyerb & G V Subba Raoc

Received 6 October 2004; revised 23July 2005

Simulation of the effect of oxalic acid as well as acetone on the bistable behaviour of the minimal bromate oscillator in a CSTR is reported. In these simulations, flow mode is set in with a minimum value of [Br-]0, the observation is done for a certain period of time and the resulting steady state value of bromide in the system [Br-]ss is noted. After this duration is over, the [Br-]0 is increased steadily with the indicated values and [Br-]ss is recorded as earlier. After reaching a certain high value of [Br-]0, the same observations are repeated by decreasing [Br-]0. The system is found to be bistable between certain ranges of [Br-]0. It has been found that this range of values of [Br-]0 is broadened when oxalic acid and/or acetone are additionally present in the minimal bromate oscillator.

 

 

Indian Journal of Chemistry

Vol. 44A, October 2005, pp. 1988-1994

 

X-ray diffraction structures of two isomeric decacarbonyltriosmium compounds of quinoxaline, [(m-H)Os3(CO)10(m-1,8-h2-C8H5N2)] and
[(
m-H)Os3(CO)10(m-1, 2-h2-C8H5N2)]

Received 24 May 2005; revised 15 July 2005

Treatment of [Os3(CO)10(MeCN)2] with quinoxaline at room temperature results in the isolation of two isomeric clusters [(m-H)Os3(CO)10(m-1,8-h2-C8H5N2)] 5 and [(m-H)Os3(CO)10(m-1,2-h2-C8H5N2)] 6 in 50 and 10% yields respectively. Compounds 5 and 6 have been characterized by spectroscopic data and single crystal X-ray diffraction studies. Compound 5 crystallizes in the triclinic space group P-1 with a = 7.895(2) Å, b = 9.187(2) Å, c = 16.741(3) Å, a = 75.494(12), b = 88.60(2), g = 66.57(2)o, Z = 2, V = 1074.8(4) Å3 and dcalc = 3.031 mg/m3; R1 = 0.0364, wR2 = 0.0870 for 2958 reflections with I > 2s (I). Compound 6 crystallizes together with an entirely independent molecule of the previously reported hydrido-hydroxy compound [(m-H)Os3(CO)10(m-OH)] 7 in the monoclinic space group P21/n with a = 9.255(2) Å, b = 16.864(3) Å, c = 26.243(7) Å, a = 90, b = 91.36(2), g = 90°, Z = 4, V = 4094.8(16) Å3 and dcalc = 3.135 mg/m3; R1=0.0410, wR2 = 0.0749 for 2958 reflections with I > 2s (I). In 5, the quinoxaline ligand coordinates through the ring N(1) atom and the C(8) carbon atom of the carbocyclic ring, whereas in compound 6, the ligand coordinates through the ring N(1) atom and the C(2) carbon atom of the heterocyclic ring.

        IPC Code: Int. Cl.7 C07D215/00; C07F15/00;G01N23/22

 

 

Indian Journal of Chemistry

Vol. 44A, October 2005, pp. 1995-2002

 

Homo- and hetero-binuclear complexes of a compartmental Schiff base ligand. Synthesis and characterisation

 

Kamalendu Deya, *, Saikat Sarkara, b, Ranabir Bhowmicka, Susobhan Biswasa & Dhananjoy Konera

Received 18 February 2005; revised 23 July 2005

Reaction of 3-formylsalicylic acid with diethylenetriamine yields the Schiff base {N,N¢–2,2¢-bis(aminoethyl)methyl­aminebis(3-carboxysalicylidimine)}(H4fsadien). The interaction of H4fsadien with CoCl2·6H2O produces [(H2fsadien)CoII] and silylation and lithiation of which, having two free –COOH groups with Me3SiCl or trimethylsilyl N,N¢-diphenylurea (TDPU) and LiOH, yields disilylated and dilithiated products, [{(Me3Si)2(fsadien)}CoII] and [{(Li)2(fsadien)}CoII], in good yield. This disilylated or dilithiated product smoothly reacts with (p-C5H5)2TiCl2, (p-C5H5)2ZrCl2, Me2SnCl2, Ph2SnCl2 and MX2.nH2O (where M=Ni2+, Cu2+, Co2+, Pd2+, VO2+and X=Cl- or CH3COO- ) affording some new homo- and hetero-binuclear complexes, including some organo-derivatives. The reactions of H4fsadien with FeCl3.6H2O and Co(NO3)2.6H2O in access of oxygen also yield di-iron(III) and di-cobalt(III) complexes. The complexes are characterised by elemental analyses, molecular weights, magnetic moment values, molar conductance values and spectroscopic data (IR and electronic) data. In all these complexes, the Schiff base, H4fsadien, functions as tetrabasic bridging hexadentate/heptadentate ligand using inner compartment of N2O2 or N3O2 donor set and outer compartment of O2O2 donor set.

 

IPC Code: Int. Cl.7 C07F15/06;C07C251/02

 

 

 

Indian Journal of Chemistry

Vol. 44A, October 2005, pp. 2003-2009

 

Synthesis and characterization of novel catalase resistant monoperoxo divanadate(V) compounds

Swapnalee Sarmaha, Diganta Kalitaa, Pankaj Hazarikab & Nashreen S Islama, *

Received 16 November 2004; revised 16 August 2005

Oxo-bridged monoperoxo-divanadium(V) compounds in mixed-ligand environment, Na6[V2O3(O2)(NTA)2(SO4)-(H2O)].2H2O (1) and Na2[V2O3(O2)(gly-gly)2(SO4)(H2O)].2H2O (2), have been synthesized by devising an unusual synthetic methodology based on the redox reaction of sodium salt of diperoxovanadate with vanadyl sulphate in presence of respective co-ligands (NTA= nitrilotriacetic acid, gly-gly= glycylglycine) at pH ca.7.0 (compound 1) or ca. 9.0 (compound 2). Magnetic susceptibility measurement, ESR and electronic spectral data reveal that V(IV) of vanadyl is completely oxidised to V(V) during the reactions. The presence of side-on bound peroxo group, terminal as well as bridging oxo groups and unidentate sulphate in the compounds are exhibited by their IR spectra. The ligands NTA in compound 1 and glyl-gly in compound 2 occur in their anionic form occupying three co-ordination positions around each of the oxo-bridged V(V) centres. The distinctive features of the compounds include their high stability towards decomposition in solution and remarkable ability to resist the action of the enzyme catalase. The compounds have been found to be inactive in the oxidation of NADH (nicotinamide adenine dinucleotide) or bromide. The dinuclear complex species appear to correspond to the inhibitor complexes formed in solution responsible for ligand induced inhibition of redox activity of a mixture of diperoxovanadate and vanadyl.

        IPC Code: Int. Cl.7 C07F9/00;G01N

 

 

 

Indian Journal of Chemistry

Vol. 44A, October 2005, pp. 2010-2014

 

Synthesis and characterization of coordination compounds of
Cd(II), Co(II), Ni(II), Cu(II) and Zn(II) with rutin

Jingwan Kang*, Biquan Su & Xiaoquan Lu

Received 12 March 2005; revised 25 June 2005

The synthesis, characterization and electrochemical properties of five novel coordination compounds of rutin with transition metal [M = Cd(II), Co(II), Ni(II), Cu(II) and Zn(II)] are reported here. These coordination compounds may be formulated as [M3L2(H2O)n](CH3COO)2 (n=6,12). Three hydroxy groups on the unsaturated rings form coordination bonds with the metal ions. The cyclic voltammetric data show changes in the redox potentials and currents of the coordination compounds relative to that of rutin. Formation of the coordination compounds changes the rigidity of rutin molecular plane and has a little influence on the antioxidation of rutin.

          IPC Code: Int. Cl.7 C07F1/08; C07F3/06;C07F3/08;C07F15/04;C07F15/06

 

 

Indian Journal of Chemistry

Vol. 44A, October 2005, pp. 2015-2023

 

Study of electrocatalytic properties of platinum-loaded poly-ortho-aminophenol film towards methanol oxidation and hydrogen evolution

 

N Bahrami Panaha, M G Mahjania,*, M Jafariana & F Gobalb

 

Received 12 July 2004; revised 17 August 2005

Platinum microparticles electrodeposited at a glassy carbon surface (Pt/GC) and within a poly-ortho-aminophenol film formed on a GC substrate (Pt/PoAP/GC) have been used for investigating their catalytic activity towards hydrogen evolution reaction and methanol oxidation by cyclic voltammetry, impedance spectroscopy and chronoamperometry. The effect of the deposition time (tdep) of the Pt particles dispersed into GC and PoAP electrodes and of the acid anions (SO42–, ClO4) on the hydrogen adsorption/desorption peaks and hydrogen evolution reaction has been studied. It has been shown that the main cause of immediate blocking of the PoAP-SO42– pores with platinum microparticles is its smaller scaling yardstick. The higher electrocatalytic activity of the PoAP as compared to that of GC due to its higher surface area for the methanol oxidation has been proved by a substantial improvement in transition current in chronoamperometric and in the maximum anodic current of the methanol in cyclic voltammetric measurements.

             IPC Code: Int. Cl.7 B01J23/00;C07B33/00;C25B;C25D

 

 

 

Indian Journal of Chemistry

Vol. 44A, October 2005, pp. 2024-2029

 

Thermal behaviour and spectral studies on cotton cellulose modified with phosphorus, sulphur and metals

J B Dahiya* & Sushila Rana

Received 25 April 2005; revised 28 July 2005

The potential flame retardancy of cellulose benzylthiophosphate (CBTP) and its metal complexes has been investigated by their thermal degradation behaviour using TG and DSC techniques from ambient temperature to 600°C in air and nitrogen atmosphere. From the resulting data of TG curve using Broido method, the activation energies of CBTP and its metal complexes for decomposition stage are found to be in the range 31-45 kJ mol1 and are lower than that of cellulose (165.85 kJ mol1) in air atmosphere. Modified cellulose samples, when heated, give rise to high char yields. The values of DH have also been found reduced and spread in wide range of temperature significantly by introducing phosphorus, sulphur and metals in cellulose. The FTIR spectra of chars of modified cellulose indicate that dehydration takes place and compounds containing C=O, C=C, P–S–P and P=O groups are formed. These and related observations suggest that such derivatisation may give rise to novel flame retardant treatments for cellulosic materials.

       IPC Code: Int. Cl.7 C08L1/08;C09K21/00;G01N

 

 

 

Indian Journal of Chemistry

Vol. 44A, October 2005, pp. 2030-2033

 

Ion-associate of arsenic(V)-salicylic acid chelate with methylene blue in toluene: Application for arsenic quantification

Subrata Kundu, Sujit Kumar Ghosh, Sudip Nath, Sudipa Panigrahi, Snigdhamayee Praharaj, Soumen Basu &
Tarasankar Pal*

Received 13 September 2004: Revised 9 August 2005

Extraction spectrophotometric method has been exploited for the selective detection and determination of arsenic in parts per million levels using salicylic acid and a cationic dye, methylene blue. Salicylic acid configures an anionic chelate with arsenic(V) and then the dye in turn forms a toluene soluble ion-associate. Using standard colour comparator chart, semi-quantitative determination of arsenic has been carried out. The method is devoid of any toxic chemical, is not interfered by phosphate, silicate, and common cations and has been successfully employed for the quantification of arsenic in real samples.

       IPC Code: Int. Cl.7C01G28/00;G01N21/00

 

 

 

 

 

 

 

Indian Journal of Chemistry

Vol. 44A, October. 2005, pp. 2034-2038

 

Structural, optical and electrical  characterizations of spray deposited CdMoO4 and CdWO4 thin films

P K Pandey*, N S Bhave & R B Kharat

Received 24 June 2005; revised 28 August 2005

Preparation of cadmium molybdate (CdMoO4) and cadmium tungstate (CdWO4) thin films for the first time by `spray pyrolysis’ using their ammonical solution as precursor, is reported here. Growth of the films takes place by pyrolytic decomposition of the spraying precursor solution onto the preheated glass substrates.
X-ray diffraction studies confirm the polycrystalline, single-phase nature of the sintered films. Scanning electron microscopic images of the thin films clearly show aggregates of microcrystallites. Optical absorption spectrum in the range 350-850 nm shows direct as well as indirect optical transitions in both the materials. The plot of log(s) versus 1/T, within the temperature range  310-600 K for both the films indicates their semiconducting nature and shows a break in the curves. The thermal activation energies below and above the break temperature have been estimated to be 0.73 eV and 0.10 eV for CdMoO4; and 0.98 eV and 0.14 eV for CdWO4, respectively. The data have been analyzed using valence and conduction band model.

        IPC Code: Int. Cl.7 C23C16/22;C01G11/00

 

 

 

Indian Journal of Chemistry

Vol. 44A, October 2005, pp. 2039-2043

 

Kinetics and mechanism of oxidation of alcohols by butyltriphenylphosphonium dichromate

Anita Kothari1, Seema Kothari1 & Kalyan K Banerji2, *

Received 11 April 2005; revised 3 August 2005

Butyltriphenylphosphonium dichromate (BTPPD) oxidizes aliphatic alcohols to the corresponding carbonyl compounds. The reaction is first order in BTPPD. The reaction exhibits a second order dependence each on the alcohol and hydrogen ions. The oxidation of deuteriated ethanol and 2-propanol indicates the presence of a substantial primary kinetic isotope effect. The reaction has been studied in nineteen organic solvents and the solvent effect was analyzed using multiparametric equations. It is observed that the cation-solvating power plays a major role in the reaction. The rate of oxidation shows excellent correlation with the polar and steric substituent constants. Suitable mechanisms have been proposed.

           IPC Code: C07B33/00

 

 

 

Indian Journal of Chemistry

Vol. 44A, October 2005, pp. 2044-2047

 

Kinetics and mechanism of oxidation of aromatic aldehydes by

N-chlorosuccinimide in aqueous acetic acid

 

Received 7 April 2005; revised 21 July 2005

Kinetics of oxidation of aromatic aldehydes by N-chlorosuccini­mide (NCS) in the presence of HClO4 and NaCl in aqueous acetic acid medium is reported here. The observed rate of oxidation is first-order with respect to [NCS], [H+] and [Cl-]. The order with respect to [aldehyde] is always zero. The rate is found to increase with decrease in the dielectric constant of the medium. Increase of ionic strength of the medium decreases the rate of oxidation. Addition of succinimide (>NH), has negligible effect on the rate of oxidation. The product of oxidation is the corresponding acid. Arrhenius and the activation parameters have been calculated. A suitable mechanism is also proposed.

IPC Code: C07B33/00

 

 

 

 

Indian Journal of Chemistry

Vol. 44A, October 2005, pp. 2048-2050

 

Oxidation of tellurium(IV) by tetrabutyl-ammonium tribromide

V A Kalantre & G S Gokavi*

Received 9 Februray 2005; revised 3 August 2005

The reaction between tetrabutylammonium tribromide and tellurium(IV) has been studied in 50% (v/v) acetic acid under second order conditions. The overall order of reaction is found to be two, unity each in both the reactants. The reaction involves a direct two-electron transfer step since the test for the formation of free radicals due to single electron step was negative. The reaction is retarded by hydrogen ions due to protonation prior equilibria of the reductant, tellurium(IV). The active species of the reactants is found to be tribromide ion of the oxidant and HTeO3- of the reductant. Considerable decrease in the entropy of activation of the reaction indicates formation of an ordered transition state between the two reactants analogous to that in alcohol oxidation by tetrabutylammonium tribromide ion.

IPC Code: Int. Cl.7 C07B31/00

 

 

Indian Journal of Chemistry

Vol. 44A, October 2005, pp. 2051-2054

 

Adsorption kinetics of Brij 35 at  air/solution interface

Zhongni Wang1,2,*, Feng Liu3 , Quanxuan Zhang1,
Xilian Wei3 , Dezhi Sun3, Ganzuo Li2,* & Gaoyong Zhang2

Received 4 October 2004; revised 28 July 2005

Dynamic surface tension and surface adsorption kinetics at the air/aqueous solution interface of dodecyl polyoxyethylene(23) ether (Brij®35, C12H25O(CH2CH2O)23H) have been investigated at different bulk surfactant concentrations and temperatures. Apparent diffusion coefficients, Da, activation barrier, εa , and the adsorption kinetic parameters, n and t* , are obtained from the extended Ward and Tordai approach, and Rosen’s empirical model, respectively. It is shown that Brij 35 solutions follow a mixed diffusion-activation adsorption mechanism. Results evaluated by the extended Ward and Tordai approach are consistent with those obtained from Rosen’s empirical model. With increase in bulk concentration from 0.1 CMC to 10 CMC (mol/dm3), εa increases from 2.40 to 6.96 kJ/mol, and n decreases from 0.620 to 0.393, while with increase in temperature from 25 to 45°C, εa decreases from 4.59 to 3.54 kJ/mol, and n decreases from 0.534 to 0.456. This indicates that the diffusion tendency decreases with increase in the interaction between surfactant molecules while the thermo-motion of the molecules favours surface adsorption.

IPC Code: Int. Cl.7 G01N30/00

 

 

Indian Journal of Chemistry

Vol. 44A, October 2005, pp. 2055-2059

 

Solvent effects on alkaline hydrolysis of N-benzylphthalimide in mixed

water-acetonitrile and mixed water-N,N-dimethylformamide

 

Cheong May Ye, Azhar Ariffin & Mohammad Niyaz Khan*

Received 13 April 2005; revised 30 June 2005

The nucleophilic second-order rate constant (kOH) for the reaction of OH- with N-benzylphthalimide appears to follow a reaction mechanism similar to that for reactions of OH- with phthalimide and its N-alkylphthalimides. The rate of hydrolysis reveals an insignificant contribution of water-catalysed cleavage of NBPT compared with its hydroxide ion catalysed reaction. The observed pseudo first-order rate constant, kobs, for alkaline hydrolysis of NBPT decreases with increase in the content of organic cosolvents (up to 70%, v/v) in mixed water-CH3CN and water-DMF solvents.

IPC Code: Int. Cl.7 C07B41/00

 

 

Indian Journal of Chemistry

Vol. 44A, October 2005, pp. 2060-2063

 

A polymeric membrane ion selective electrode based on organic-inorganic

composite ion exchanger for the determination of thorium(IV)

 

Sulekh Chandraa,*, Himanshu Agarwala, Chandan Kumar Singha, Susheel Kumar Sindhub & Pankaj Kumarb

Received 3 March 2005; revised 10 August 2005

A poly(vinyl chloride) membrane electrode based on organic-inorganic composite ion exchanger, tin(IV) tungstoselenate-pyridine, has been prepared and tested for the selective determination of thorium(IV) ions. The PVC membrane electrode comprising 16% composite ion exchanger as the electroactive phase, 50% o-dioctyl phthalate as plasticizer, 4% tetraphenyl borate as anionic excluder and 30% poly(vinyl chloride) displays a linear response to thorium(IV) ions over a wide concentration range of 1.0´10-1-8.0´10-6 M with a Nernstain slope of 14.2 mV/ decade. The electrode shows a very short response time (~15 s) and may be used in the pH range 2.5-9.0. The selectivity coefficient for alkali, alkaline earth and transition is smaller than 4.0´10-4. The sensor has been successfully used as an indicator electrode in the potentiometric titration of Th4+ with EDTA as well as also for the determination of Th4+ in the binary mixtures.

 

         IPC Code: Int. Cl.7 B01J39/00; C01F15/00; G01N30/96; H01M4/00