Indian Journal of Chemical Technology

Indian Journal of Chemical Technology
Total visitors: 2,476 since 25-11-05

Volume 12	Number 6			November 2005
CODEN:ICHTEU 12(6) 621-758			ISSN:0971-457X

CONTENTS
Research articles

Synergistic effect of NTMP, Zn²⁺ and ascorbate in corrosion inhibition of carbon steel	629
IPC Code: C23F11/00
B V Appa Rao, S Srinivasa Rao & M Sarath Babu
Effect of Cr(VI) - Fe(II) interaction on the corrosion resistances of iron at different pH in dichromate solutions	635
IPC Code: C23F13/00; C23F15/00
I B Singh, G Venkatachari, D R Singh, M Singh & A H Yegneswaran
Wood bark oils as vapour phase corrosion inhibitors for metals in NaCl and SO₂ environments	641
IPC Code: C23F11/00
N Poongothai, P Rajendran, M Natesan & N Palaniswamy
Electrodeposition of cobalt from cobalt chloride-N-(n-butyl) pyridinium chloride molten salt	648
IPC Code: C22B23/00; C25C1/08; C01G51/00
M R Ali, A Nishikata & T Tsuru
A study of thermal drying process	654
IPC Code: D06F
A K Haghi & H Ghanadzadeh
Studies on graft copolymerization of N-vinyl formamide onto guar gum initiated by bromate/ascorbic acid redox pair	664
IPC Code: C08B3/00
Kunj Behari, Jaya Banerjee, Arti Srivastava & Dinesh Kumar Mishra
Potassium dichromate initiated polymerization of aniline	671
IPC Code: C07C211/46; C08F2/00
P Chowdhury & B Saha
Effect of rare earth metal ions on the structural and textural properties of NaFAU-Y zeolite and vapor phase alkylation of benzene with 1-octene	676
IPC Code: C22B59/00; C07C15/04
Bejoy Thomas & Sankaran Sugunan
Thermodynamic and ultrasonic studies of biomolecules in aqueous solutions of metal ion at 303.15K	689
IPC Code: B01J19/00
P R Malasane & A S Aswar
Effect of surface modification of carbon black by 1,2 dihydroxy benzene and 1,2,3 trihydroxy benzene on a natural rubber-carbon black composite	695
IPC Code: C08C1/02
S Ganguly, P Bhattacharya & A N Banerjee
Simultaneous determination of titanium and molybdenum in alloy steels using derivative spectrophotometry in neutral micellar medium	701
IPC Code: G01J3/00; C22B34/00
A M A Khadar & Anitha Varghese
Extraction of uranium from acidic media with a novel synergistic mixture of di-nonyl phenyl phosphoric acid and tri-n-octyl phosphine oxide	708
IPC Code: C22B60/02
S L Mishra, R Vijayalakshmi & H Singh
Studies on extraction of chromium(VI) from acidic solution by emulsion liquid membrane	713
IPC Code: C22B3/06; C22B34/32
Sekhar Chakraborty, Siddhartha Datta & Pinaki Bhattacharya
Role of instrumental techniques in studies on wet oxidation of coal: A review	719
IPC Code: C07B33/00; C10
Raja Sen, Sunil K Srivastava & Madan M Singh
*Notes*
Indirect complexometric determination of mercury(II) using 1-propane thiol (PT) as a selective masking agent	727
IPC Code: C22B43/00
P Parameshwara, J Karthikeyan, A Nityananda Shetty & Prakash Shetty
*Educator*
Kinetic theory-From Euler to Maxwell	730
Jamie Wisniak
*Chem-Tech Scan*	743
*List of Referees*	747
*Annual Author Index*	749
*Annual Keywords Index*	752
*Guidelines for Authors*	757

Indian Journal of Chemical Technology
Vol. 12, November 2005, pp. 629-634

Synergistic effect of NTMP, Zn²⁺ and ascorbate in corrosion inhibition of carbon steel

B V Appa Rao*, S Srinivasa Rao & M Sarath Babu

Nitrilotris(methylenephosphonic acid) (NTMP) inhibits corrosion of carbon steel in presence of Zn²⁺ . However, in order to make the inhibitor more environment friendly, it is necessary to reduce the levels of Zn²⁺ or phosphonate or both by introducing an environment friendly organic salt as a second synergist. In this paper, the inhibitive action of ascorbate as a second synergist in the presence of relatively low concentrations of NTMP and Zn²⁺, is presented. Addition of just 25 ppm of ascorbate to 20 ppm each of NTMP and Zn²⁺, at pH=7, increased the inhibition efficiency markedly from 35 to 95%. In the pH range of 6-4, the concentration of ascorbate required to bring up the inhibition efficiency to 94%, is only 10 ppm. However, the alkaline region demanded relatively higher concentration of ascorbate. This ternary system is quite effective in a wide pH range, 4-10. This is the uniqueness of this new synergistic formulation. Potentiostatic polarization studies indicated that this synergistic formulation acts as a mixed inhibitor, predominantly cathodic in nature. A large increase in charge transfer resistance and also a decrease in double layer capacitance of the surface film, were observed from a.c. impedance studies. X-ray photoelectron spectrum of the surface film indicated the presence of the elements, viz., P, O, N, C, Zn and Fe in the film. The shifts in binding energies of these elements indicated the presence of oxides and hydroxides of iron and zinc as well as complexes of Fe(III) and Zn(II) with phosphonate and ascorbate. The reflection absorption FTIR spectrum of the surface film also supported the formation of insoluble complexes of phosphonate and ascorbate with metal ions as well as presence of Zn(OH)₂ on the metal surface. A suitable mechanism of corrosion inhibition is proposed, which corroborates all the above experimental results.

Keywords: Synergism, ascorbate, carbon steel, NTMP, corrosion inhibition
IPC Code: C23F11/00

Indian Journal of Chemical Technology
Vol. 12, November 2005, pp. 635-640

Effect of Cr(VI) - Fe(II) interaction on the corrosion resistances of iron at different pH in dichromate solutions

I B Singh* , G Venkatachari, D R Singh, M Singh & A H Yegneswaran

Effect of Cr(VI) - Fe(II) interaction on the corrosion resistance of iron in dichromate solutions has been studied under different experimental conditions. The presence of dissolved oxygen (DO) in the solution decreases Cr(VI) reduction by Fe(II) at pH 4 which became quite noticeable at pH 7. This probably influences corrosion of iron to certain extent. A positive shift of OCP and measurements of a higher charge transfer resistances of iron in dichromate solution of pH 2 and 3 suggest the formation of a protective film on iron. Energy Dispersive X-ray Analysis (EDXA) of iron immersed in Cr(VI) solution indicated a greater involvement of chromium in the formation of a protective film at iron surface. On the other hand, the EDXA analysis showed a decrease in chromium concentration in the reaction product film on the immersed iron surfaces in Cr(VI) solution at pH 4 and above. A shift of OCP in the negative direction and the occurrence of lower charge transfer resistance at the above pH as compared to pH 2 and 3 is attributed to a decrease in the protective properties of the film.

Keywords: Iron, dichromate ion, corrosion resistance, Cr(VI) - Fe(II) interaction

IPC Code: C23F13/00; C23F15/00

Indian Journal of Chemical Technology
Vol. 12, November 2005, pp. 641-647

Wood bark oils as vapour phase corrosion inhibitors for metals in NaCl and SO₂environments

N Poongothai, P Rajendran, M Natesan* & N Palaniswamy

Wood bark oils of Cassia siamea-gonrai (CS), Cassia auriculata (CA), Crataeva religiosa (CR) and Strychnos nux-vomica (SNV) were extracted from the dry bark. These highly volatile oils are used as a vapour phase corrosion inhibitors (VPI) for mild steel and copper in sodium chloride and sulphur dioxide environments. The inhibition efficiency of these wood bark oils has been examined by using weight loss, potentiodynamic polarization and A.C. impedance spectroscopic methods. It has been found that the inhibition capability of these oils increases with increase in concentration from 0.4 to 4%. The results indicate that the bark oils have significant inhibitive effect. This is due to adsorption of inhibitor molecule on the metal surface. At higher concentration (8%) of the inhibitor, there is decrease in inhibition efficiency. It may be due to the formation of soluble metal-inhibitor complex in the salt environments. It has also been found that 4% concentration of these inhibitors offered, above 90% inhibition efficiency for both mild steel and copper.

Keywords: Mild steel, copper, corrosion, NaCl, bark oils, vapour phase inhibitor, inhibition efficiency

IPC Code: C23F11/00

Indian Journal of Chemical Technology
Vol. 12, November 2005, pp. 648-653

Electrodeposition of cobalt from cobalt chloride-N-(n-butyl)pyridinium chloride molten salt

M R Ali*, A Nishikata & T Tsuru

A molten salt system of CoCl₂-N-(n-butyl)pyridinium chloride (BPC) having melting point <80^oC has been developed over a wide composition range (1:2 to 1:1 mole ratio CoCl₂-BPC) and the electrodeposition of cobalt has been carried out by constant current and constant potential methods at 110^oC. Cobalt cannot be deposited from a CoCl₂-BPC melt containing BPC concentration higher than the mole ratio of 1:2, whereas it can be deposited from BPC concentration lower than the mole ratio of 1:2. The deposition reaction mechanisms of cobalt in the CoCl₂-BPC molten bath are revealed by electrochemical analysis. The experimental Tafel slope of 62 mV dec^-1 and the calculated transfer coefficient () of 1 (one) suggest that the rate determining step is a chemical reaction involving the release of the complexing agents occurring after first charge transfer step. X-ray diffractometer and scanning electron microscope have been used to investigate the influence of electrodeposition conditions and the morphology of the electrodeposited layers. The cathodic current efficiency for the deposition of cobalt is about 98%.

Keywords: Electrodeposition, cobalt N-(n-butyl)pyridinium chloride

IPC Code: C22B23/00; C25C1/08; C25D1/16; C01G51/00

Indian Journal of Chemical Technology
Vol. 12, November 2005, pp. 654-663

A study of thermal drying process
A K Haghi* & H Ghanadzadeh

Different aspects of heat and water transfer through textiles are reviewed in this paper. The study illustrates the impact of the heat transfer process on the moisture transfer processes, including moisture transfer by water diffusion, liquid capillary action, and moisture sorption of the fibres. It is also concluded that the fiber hygroscopicity is another key factor in determining the coupling effect between heat and moisture transfer processes.

Keywords: Heat transfer, moisture transfer, drying process, wool fibre

IPC Code: D06F

Indian Journal of Chemical Technology
Vol. 12, November 2005, pp. 664-670

Studies on graft copolymerization of N-vinyl formamide onto Guar gum initiated by bromate/ascorbic acid redox pair

Kunj Behari*, Jaya Banerjee, Arti Srivastava & Dinesh Kumar Mishra

An unreported graft copolymer of guar gum with N-vinyl formamide has been synthesized using potassium bromate/ascorbic acid redox pair. By studying the effect of the concentration of monomer, bromate ion, ascorbic acid, guar gum along with the effects of time and temperature on the grafting characteristics: grafting ratio (%G), add on (%A), conversion (%C), efficiency (%E), homopolymer (%H) and rate of grafting (Rg), the reaction conditions for optimum grafting have been determined. The maximum grafting ratio, add on, conversion, efficiency and rate of grafting were obtained at minimum concentration of N-vinyl fomamide (NVF) i.e. at 10×10^-2 mol dm^-3. The maximum values of these parameters were observed at minimum temperature (35°C) and minimum reaction time (120 min). On increasing the concentration of ascorbic acid from 0.4×10^-3 to 2.0×10^-3 mol dm^-3 the above parameters show increasing trend while on increasing the concentration of bromate ion from 0.2 to 1.8×10^-2 mol dm^-3 the parameters show decreasing trend. Infrared spectra of Guar gum and guar gum-g-NVF has been investigated. Thermogravimetric analysis and differential scanning calorimetric analysis showed that guar gum-g-NVF was thermally more stable than guar gum.

Keywords: Graft copolymerization, Guar gum, N-vinyl formamide, redox pair, differential scanning calorimetry

IPC Code: C08B3/00

Indian Journal of Chemical Technology
Vol. 12, November 2005, pp. 671-675

Potassium dichromate initiated polymerization of aniline

P Chowdhury^* & B Saha

Potassium dichromate initiated polymerization of aniline in acidified aqueous medium was carried out as a function of parameters such as pH, aniline/oxidant mole ratio, temperature and time. Optimum reaction conditions are outlined for the chemical synthesis of the polymer. Spectral, thermal, electrical and viscosity properties of some selective samples of polyaniline were studied. A reaction scheme has been proposed to elucidate the role of Cr(VI).

Keywords: Polyaniline, dichromate oxidation, conductivity, UV-VIS spectra, FTIR spectra

IPC Code: C07C211/46; C08F2/00

Indian Journal of Chemical Technology
Vol. 12, November 2005, pp. 676-688

Effect of rare earth metal ions on the structural and textural properties of NaFAU-Y zeolite and vapour phase alkylation of benzene with 1-octene

Bejoy Thomas & Sankaran Sugunan*

Rare earth exchanged (La³⁺, Ce³⁺, RE³⁺, Sm³⁺) Na-Y zeolites were prepared by simple ion exchange methods. X-ray diffraction pattern and IR spectral studies show that the frameworks remain intact after exchange with rare earth metal ions. The surface acidic properties were determined by temperature programmed desorption of ammonia (NH₃-TPD). ¹H MAS-NMR spectral study shows the presence of highly acidic bridging hydroxy groups in the zeolite structure. Considerable enhancement in the acid structural properties is observed on rare earth exchange. Strain induced by the bulky rare earth metal cations on the zeolitic framework has been followed by a perceptible shift in the positions of ²⁹Si and ²⁷Al MAS-NMR spectral peaks. The migration of counter cations, especially lanthanum, in the repulsive electrostatic field of sodium has been established using ²⁹Si and ²⁷Al MAS-NMR studies. The catalytic efficiency of the prepared systems was tested for the alkylation of benzene with 1-octene. Zeolite Na-Y shows very low activity due the negative influence of Na⁺ions onthe Brönsted acid centres. Rare earth exchanged forms invariably show better selectivity for the desired 2-phenyloctane formation. Catalysts are susceptible for deactivation due to blocking of the pores by alkylation products. These studies show that the rare earth exchanged zeolites exhibit better resistance towards deactivation.

Keywords: Brönsted acidity, framework aluminium, Hirschler-Plank mechanism, linear alkylbenzene, magic angle spinning NMR, migration behaviour, oxidative treatment, rare earth exchanged Na-Y zeolite, regioselective alkylation, Sanderson’s principle

IPC Code: C22B59/00; C07C15/04

Indian Journal of Chemical Technology
Vol. 12, November 2005, pp. 689-694

Thermodynamic and ultrasonic studies of biomolecules in aqueous solutions of metal ion at 303.15K

P R Malasane & A S Aswar*

Ultrasonic velocity, density and viscosity of tryptophan and glycine in aqueous solutions of ZnCl₂ as well as CoCl₂ have been measured at 303.15 K experimentally. From these experimentally measured values, the apparent molar volume (ф_v), apparent molar compressibility (ф_K), viscosity coefficients of Jones-Dole equation and other parameters have been calculated at experimental temperature. These values have been used to explain molecular association, solute-solvent interactions through hydrogen bonding and solvation. The results have been discussed in the light of existing theories of molecular interactions and structural effects on solvent in solution.

Keywords: Ultrasonic velocity, viscosity, biomolecule, metal ion

IPC Code: B01J19/00

Indian Journal of Chemical Technology
Vol. 12, November 2005, pp. 695-700

Effect of surface modification of carbon black by 1,2 dihydroxy
benzene and 1,2,3 trihydroxy benzene on a natural rubber-carbon black composite
s Ganguly, P Bhattacharya & A N Banerjee^*

Present study deals with an attempt to modify the surface chemistry of N330 carbon black by the interaction with aromatic derivatives. Two aromatic polyhydroxy compounds, namely 1,2 dihydroxy benzene (catechol) and 1,2,3 trihydroxy benzene (pyrogallol) are chosen as surface modifiers. It has been shown that the lone pair of electrons of the oxygen has contributed to the higher interaction with existing functional groups of carbon black giving an increased crosslinking density. The surface modified carbon black when compounded with natural rubber has produced rubber compounds with improved rheological and visco-elastic properties. It has been noted that dynamic mechanical properties like heat build-up and hysteresis loss have also been improved and in some cases improved abrasion loss properties have been achieved. The results indicate that there has been as enhancement of filler-polymer interaction with a reduction of filler-filler networking. The effect of increased crosslinking phenomenon and filler-polymer interaction are more pronounced for catechol than that for pyrogallol.

Keywords: Carbon black, natural rubber, surface modification, catechol, pyrogallol

IPC Code: C08C1/02

Indian Journal of Chemical Technology
Vol. 12, November 2005, pp. 701-707

Simultaneous determination of titanium and molybdenum in alloy steels using derivative spectrophotometry in neutral micellar medium

A M A Khadar* & Anitha Varghese

A simple, selective and sensitive spectrophotometric method has been developed for the individual and simultaneous determination of Ti(IV) and Mo(VI) using salicylaldehyde p-hydroxybenzoylhydrazone (SAPHBH) in presence of Triton X-100, without any prior separation. Beer’s law is obeyed between 0.15-2.0 and 0.20-2.51 m gmL^-1 concentration of Ti(IV) and Mo(VI) at 470 and 410 nm, respectively. The molar absorptivity and Sandell’s sensitivity of the coloured species at pH 2.6 are 2.0 ´ 10⁴and 3.5 ´ 10⁴Lmol^-1cm^-1 and 2.5 and 2.7 ng cm^-2for Ti(IV) and Mo(VI), respectively. The stoichiometry of the complexes were found to be 1:2 and 1:1 (metal : ligand) for Ti(IV) and Mo(VI), respectively. These metal ions interfere with the determination of each other in zero order spectrophotometry. The first derivative spectra of these complexes permitted a simultaneous determination of Ti(IV) and Mo(VI) at zero crossing wavelengths of 520 and 440 nm, respectively. The optimum conditions for maximum colour development and other analytical parameters were evaluated. The proposed method has been successfully applied for the determination of titanium and molybdenum in standard alloy steel and mineral samples.

Keywords: Titanium, molybdenum, derivative spectrophotometry, micellar medium, salicylaldehyde p-hydroxybenzoylhydrazone

IPC Code: G01J3/00; C22B34/00

Indian Journal of Chemical Technology
Vol. 12, November 2005, pp. 708-712

Extraction of uranium from acidic media with a novel synergistic mixture of di-nonyl phenyl phosphoric acid and tri-n-octyl phosphine oxide

S L Mishra, R Vijayalakshmi & H Singh*

The extraction of uranium from aqueous acidic solutions of nitrate, perchlorate, sulphate, chloride and phosphate with a novel synergistic mixture of di-nonyl phenyl phosphoric acid (DNPPA) and tri-n-octyl phosphine oxide (TOPO) in an aliphatic hydrocarbon diluent has been studied at varying concentrations of aqueous acids, extractant and uranium. The mole ratio [DNPPA]:[TOPO] has been found to have a significant effect on extraction of uranium. Maximum extraction was found at 2:1 mole ratio and no antagonistic effect was observed at higher concentration of TOPO. The extracted species has been found to be UO₂(HR₂)₂.TOPO. The extraction order of uranium in aqueous media follows the sequence: perchlorate > nitrate > chloride > sulphate > phosphate. The selectivity of uranium with respect to other metals including Zn, Cu, Ni, Ca, and Fe has been investigated as a function of concentrations of sulphuric acid and extractant. Based on these findings, extraction of uranium has been carried out from leach liquor generated at an industrial plant, using 0.03 M DNPPA + 0.015 M TOPO with high recovery (>99%), selectivity and having added advantage of low inventory cost on extractants.

Keywords: Uranium, solvent extraction, DNPPA, TOPO, synergistic mixture

IPC Code: C22B60/02

Indian Journal of Chemical Technology
Vol. 12, November 2005, pp. 713-718

Studies on extraction of chromium(VI) from acidic solution by

emulsion liquid membrane

Sekhar Chakraborty, Siddhartha Datta^* & Pinaki Bhattacharya

High molecular weight amines, quaternary salts etc. have the potential of removing heavy metal ions including the toxic ones at low concentrations. In the present work an attempt has been made to extract Cr(VI) through emulsion liquid surfactant membrane (or, emulsion liquid membrane-ELM) from it’s acidic solution using alamine-336 and caustic soda as extractant and striping reagents respectively. Around 97% extraction of Cr(VI) from aqueous solutions of potassium dichromate through batch experimentations have been achieved. Being crucial to the overall success of the ELM processes, experiments on emulsion stability have also been performed to arrive at a reasonably stable emulsion composition. Effect of various process parameters such as initial solute concentration, concentration of internal phase etc. as also that of pH on extraction of chromium have been investigated.

Keywords: Emulsion liquid membrane, alamine-336, simultaneous extraction and stripping, equilibrium concentration, ELM

IPC Code: C22B3/06; C22B34/32

Indian Journal of Chemical Technology
Vol. 12, November 2005, pp. 719-726

Role of instrumental techniques in studies on wet oxidation of coal: A review

Raja Sen, Sunil K Srivastava* & Madan M Singh

Coal being a complex macromolecular solid is insoluble in most organic solvents. For structural studies, coal has to be subjected to chemical degradation to generate smaller fragments, which are more amenable for characterisation. For this, oxidative degradation is commonly used. A large number of wet oxidising agents have been used by researchers. All these oxidising agents have shown different reactivities and mode of attack with respect to coal. However, for structural analysis to be successful the fragments generated by oxidation must be well characterised to generate the maximum information. This review discusses the use of various instrumental techniques used to characterise the oxidation products.

Keywords: Coal oxidation, gas chromatography, GCMS, HRMS, FTIR, XPS

IPC Code:C07B33/00; C10

Indian Journal of Chemical Technology
Vol. 12, November 2005, pp. 727-729

Indirect complexometric determination of mercury(II) using 1-propane thiol (PT) as a selective masking agentP Parameshwara, J Karthikeyan, A Nityananda Shetty^* & Prakash Shetty

A complexometric method for the determination of mercury(II) in presence of other metal ions is described based on the selective masking action of 1-propane thiol towards mercury(II). Mercury(II) present in a given sample solution is first complexed with an excess of EDTA and the unreacted EDTA is titrated against lead nitrate solution at pH 5-6 (hexamine buffer) using xylenol orange as the indicator. A 0.8% aqueous solution of 1-propane thiol is then added to displace EDTA from the Hg(II)-EDTA complex. The released EDTA is titrated with standard lead nitrate solution as before. Reproducible and accurate results are obtained for 4-85 mg of mercury(II), with relative error less than ±0.23 % and coefficient of variation not more than ±0.41 %. The effects of various ions were studied. The method is used for the analysis of mercury(II) in its synthetic alloy mixtures and also in complexes.

Keywords: Mercury(II), 1-propane thiol, masking agent, complexometric titration

IPC Code: C22B43/00

Indian Journal of Chemical Technology
Vol. 12, November 2005, pp. 730-742

Kinetic theory ¾ From Euler to Maxwell

Jaime Wisniak

Acceptance of the kinetic theory of gases was the entrance to the development of the concepts that presently explain the structure of matter. The basic ideas of the Greek philosophers remained dormant for several centuries until Euler, Bernoulli, Herapath, Waterston, Clausius, and Maxwell, injected a sounder physical picture that led to our actual understanding of the structure of a gas.