Indian Journal of Chemical Technology

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VOLUME 14

NUMBER 5

SEPTEMBER 2007

CODEN:ICHTEU

 

ISSN:0971-457X

 

CONTENTS

 

Papers

 

 

Arsenic removal by conventional and membrane technology: An overview

441

        IPC Code(s): B01D61/02, B01D61/14

 

        Md Tamez Uddin, Md Salatul Islam Mozumder, A Figoli, Md Akhtarul Islam &

        E Drioli

 

 

Synthesis of chloride ion-selective potentiometric sensor based on coordination polymer complex

 

451

        IPC Code(s): C08B1/00

 

        R Sundaram & K S Hariprasad

 

 

Mechanism of oxidation of hexamine by quinoliniumdichromate(QDC) in aqueous perchloric acid

 

459

        IPC Code(s): C07D487/18

 

        S A Chimatadar, S V Madawale & S T Nandibewoor

 

 

Kinetics and mechanism of the hydroxylation of some naphthalene sulphonic acid derivatives by peroxodisulphate

 

466

        IPC Code(s): C07C7/00

 

        Ahmed A Abdel-Khalek, Eman S Hassan & Hala M Hassan

 

 

FCC riser hydrodynamics: Effect of some operating variables

473

        IPC Code(s): C10G32/00

 

        S Das (Bose), R K Saha & P Sen Gupta

 

 

Azole, amine, benzoate and nitrate compound mixture as VPI for metals in NaCl and SO2 environments

 

481

        IPC Code(s): C23F11/00, D21H21/38

 

        N Poongothai, M Natesan, N Palanisamy, S C Murugavel & T Ramachandran

 

 

Corrosion studies of Ni-free austenitic stainless steel in methanol containing H2SO4, HCl and LiCl

 

488

        IPC Code(s): C23F11/00, G01N17/00

 

        V B Singh & Monali Ray

 

 

Inhibitive effect of some gemini surfactants on mild steel corrosion in acid solutions

494

        IPC Code(s): C23F11/00

 

        H K Sharma & M A Quraishi

 

 

Corrosion inhibition of N80 steel in hydrochloric acid by phenol derivatives

501

        IPC Code(s): C23F11/00

 

        S Vishwanatham & Nilesh Haldar

 

Removal of copper from water samples by sorption onto powdered limestone

507

        IPC Code(s): G01N33/18, B01D15/00

 

        S E Ghazy & A H Ragab

 

 

Effect of monomer feed rate on the properties of copolymer butyl acrylate/vinyl acetate in semi-batch emulsion polymerization

 

515

        IPC Code(s): C08F2/00

 

       M S A Palma

 

 

Notes

 

 

Development and validation of spectrophotometric method for estimation of anti-asthmatic drug doxofylline in bulk and pharmaceutical formulation

 

523

        IPC Code(s): G01J3/00, A61K

 

        M M Kamila, N Mondal & L K Ghosh

 

 

Bioinorganic studies on Fe (II)-zidovudine (azt) complex

526

        IPC Code(s): A61K, A01N59/00

 

        Ratnesh Das & K S Pitre

 

 

Synthesis, characterization and thermal studies of boron containing phenolic and cardanolic polymers

 

529

        IPC Code(s): C08G6/00

 

        Rosy Antony & C K S Pillai

 

 

A study of structure and properties of lightly cross-linked polyethylene, crystallized from the melt under uniaxially stretching

 

532

        IPC Code(s): C08F10/02

 

        B B Acharya, S Mohanty & G S Roy

 

 

Biocide injection as a means of internal corrosion control of oil pipelines

536

        IPC Code(s): F16L57/00, A01N25/00

 

        D F Aloko & A D Mohammed

 

 

Author Index

 

539

Keyword Index

 

540

 

Indian Journal of Chemical Technology

Vol. 14, September 2007, pp. 441-450

 

Arsenic removal by conventional and membrane technology: An overview

 

Md Tamez Uddin*, Md Salatul Islam Mozumder, A Figoli, Md Akhtarul Islam & E Drioli

 

Presently used arsenic removal technology has been reviewed, pointing especially to the promise of membrane technologies as a practical means of purification. The membrane technologies include reverse osmosis (RO), nanofiltration (NF), ultrafiltration (UF) and microfiltration (MF). Among them, the applications of the first two have proved to be reliable in removing arsenic from water. The influence of membrane materials, membrane type, operating conditions such as temperature, pressure, pH of the feed solution and feed concentration on arsenic removal efficiency by membrane technologies are discussed. This paper also provides a comparison between conventional technologies and membrane technologies for arsenic removal and concludes that membrane technology is preferred for water treatments to meet the maximum contaminant limit (MCL) standard.

Keywords: Arsenic removal, Adsorption, Membrane technology, Reverse osmosis, Nanofiltration, Ultrafiltration, Microfiltration

IPC Code (s): B01D61/02, B01D61/14

 

Indian Journal of Chemical Technology

Vol. 14, September 2007, pp. 451-458

 

Synthesis of chloride ion-selective potentiometric sensor based on coordination polymer complex

 

R Sundaram* & K S Hariprasad

 

This paper describes the fabrication of an ion-selective electrode in which a 2,5-dihydroxy-p-benzoquinone (DHBQ) is used as the ionophore. The polymers prepared were characterized by elemental analyses, FT-infrared spectra, solid state electrical conductivity studies leading to activation energy, conductance measurements and thermoelectric power measurements. The DC conductance (1/R) values of Fe(III)-DHBQ, Co(II)-DHBQ, Ni(II)-DHBQ and Cu(II)-DHBQ are 8.75´ 10-8, 11.8´ 10-8, 8.33´ 10-8 and 1.28´ 10-8 W -1, respectively. The current increase exponentially against temperature proves the semiconductive nature. Thermoelectric power (TEP) measurements showed the sign of the seebeck coefficient which was positive in the temperature range and hence it was concluded that the majority carriers are of n-type. The low activation energy is interpreted in terms of intermediate trap levels. The main advantage of the electrode is that it is mechanically stable up to 3 years. The electrode shows a linear response in the range of 2.5 ´ 10-5 – 0.5 ´ 10-1 mol dm-3. The response time of the electrode is 30 s. The pH range at which the electrode works is 3.8 to 6.8. The electrode was found to be selective towards chloride ion in the presence of ions like Na+, Ca2+, Mn2+, Fe3+, Co2+, Cu2+, Zn2+, CH3COO, NO3, SO42–, Br and NO2.

Keywords:     Coordination polymers, Polychelates, Electrical conductance measurement

IPC Code(s): C08B1/00

 

Indian Journal of Chemical Technology

Vol. 14, September 2007, pp. 459-465

 

Mechanism of oxidation of hexamine by quinoliniumdichromate (QDC) in aqueous perchloric acid

 

S A Chimatadar, S V Madawale & S T Nandibewoor*

 

The kinetics of oxidation of hexamine by quinoliniumdichromate (QDC) has been investigated spectrophotometrically in aqueous perchloric acid medium at constant ionic strength. The reaction is first order with respect to oxidant and reductant. Increase in perchloric acid concentration increases the reaction rate and order with respect to acid concentration is nearly two. The added products chromium(III), formaldehyde and oxime do not have any significant effect on the rate of reaction. Increase in ionic strength and decrease in dielectric constant of the reaction medium increases the rate of reaction. A suitable mechanism is proposed and the constants involved have been obtained. The activation parameters were evaluated with respect to slow step of the mechanism and discussed.

Keywords: Oxidation, Reduction, Kinetics, Hexamine, Quinoliniumdichromate(QDC)

IPC Code (s): C07D487/18

 

Indian Journal of Chemical Technology

Vol. 14, September 2007, pp. 466-472

 

Kinetics and mechanism of the hydroxylation of some naphthalene
sulphonic acid derivatives by peroxodisulphate

 

Ahmed A Abdel-Khalek*, Eman S Hassan & Hala M Hassan

 

Oxidation of 1,8-dihydroxynaphthalene-3,6-disulphonic acid (CTA) and 1-amino-4-naphthalene sulphonic acid (ANS) by potassium peroxodisulphate leads to hydroxylation of these organic compounds. These oxidations may proceed through inner-sphere electron transfer as in case of ANS or by outer-sphere mechanism in case of CTA. The homolytic fission of S2O82- is the rate determining step in the oxidation of CTA by S2O82- , whereas, the intramolecular electron transfer in the precursor compounds is the rate determining step in the mechanism of oxidation of ANS. Hydroxylation takes place in para-position of benzene ring in CTA and ortho-position in ANS. The thermodynamics activation parameters were calculated. Rate of oxidation of both CTA and ANS in methanol-water solvent mixtures is decreased by increasing methanol content in the medium.

Keywords: Oxidation, Hydroxylation, Peroxodisulphate, Kinetics, Chromotropic acid, 1-Amino-4-naphthalene sulphonic acid

IPC Code (s): C07C7/00

 

Indian Journal of Chemical Technology

Vol. 14, September 2007, pp. 473-480

 

FCC riser hydrodynamics: Effect of some operating variables

S Das (Bose)*, R K Saha & P Sen Gupta

 

Fluidized bed catalytic cracking is an important secondary process in a modern refinery. Unlike in western countries Indian refineries are often operated in distillate mode requiring design modifications and changes in operating conditions. Riser hydrodynamics together with cracking kinetics are often very useful to simulate the performance of FCC riser reactor and accurately predict conversion of the process. The present paper reports the experimental data on hydrodynamics of a FCC riser including its pressure and voidage profiles along the riser length in a cold model of the FCC unit assembly. Effects of some operating variables on the riser hydrodynamics have been reported.

Keywords:  FCC riser, Hydrodynamics, Pressure and voidage profiles, Conversion

IPC Code(s): C10G32/00

 

Indian Journal of Chemical Technology

Vol. 14, September 2007, pp. 481-487

 

Azole, amine, benzoate and nitrate compound mixture as VPI for metals in NaCl and SO2 environments

 

N Poongothai*, M Natesan, N Palanisamy, S C Murugavel* & T Ramachandran

 

A variety of tests were performed to evaluate the feasibility of vapour phase corrosion inhibitor’s (VPI’s) application for maintenance and protection of transporting metal articles from corrosion damage. Three types of VPI were evaluated for their inhibition characteristics for mild steel (MS) and copper. Minimum dosage of one g/L is required for protections of both metals. Influence of SO2 and chloride contamination on inhibitor performance was also investigated. The corrosion behaviour of MS and Cu in sodium chloride (0.005 M NaCl) environment in presence of VPI impregnated and unimpregnated paper has been studied by using weight loss, potentiodynamic polarization and A.C impedance spectroscopic methods. It has been found that 1g L-1 of VPI impregnated on Kraft paper provides nearly 98% inhibition efficiency for mild steel and copper in 0.005 M NaCl environment.

Keywords: Vapour phase corrosion inhibitors (VPI), Mild steel (MS), Copper, Inhibition efficiency, Sodium chloride

IPC Code (s): C23F11/00, D21H21/38

 

 

Indian Journal of Chemical Technology

Vol. 14, September 2007, pp. 488-493

 

Corrosion studies of Ni-free austenitic stainless steel in methanol containing H2SO4, HCl and LiCl

 

V B Singh* & Monali Ray

 

The corrosion behaviour of an austenitic stainless steel containing nitrogen with negligible amount of nickel has been investigated in methanol-H2SO4, methanol-HCl, and methanol-LiCl solutions using potentiostatic polarization technique. The cathodic reaction was the hydrogen evolution reaction. Active, passive and transpassive behaviours were observed only at high concentrations of H2SO4 (0.01-1.0 M) in methanol, and passivity was due to the high inherent water content in sulphuric acid. Pitting was also observed on the steel surface. The pitting potential became nobler as the concentration of H2SO4 increased. In 0.1 and 1.0 M H2SO4, a cathodic loop, characterized by measured negative current in the anodic region, was also observed. In methanol-HCl and methanol-LiCl solutions, the steel dissolved actively and no active-passive transition was observed. The corrosion rate was significantly higher in methanol-HCl solution as compared to methanol-LiCl due to the synergistic effects of acid and chloride ion.

Keywords: Austenitic stainless steel, Potentiostatic polarization, Corrosion, Passivity, Pitting

IPC Code (s): C23F11/00, G01N17/00

 

Indian Journal of Chemical Technology

Vol. 14, September 2007, pp. 494-500

 

Inhibitive effect of some gemini surfactants on mild steel
corrosion in acid solutions

 

H K Sharma* & M A Quraishi

 

Four gemini surfactants namely N-trimethyl butane-diyl-1,2-ethane-bis-ammonium bromide (BEAB), N-hexane-diyl-1,2-ethane-bis-ammonium bromide (HEAB), N–dodecane-diyl-1,2-ethane-bis-ammonium bromide (DDEAB) and N-hexadecane-diyl-1,2-ethane-bis-ammonium bromide (HDEAB) were synthesized in the laboratory and their influence on the inhibition of corrosion of mild steel in 1 N hydrochloric acid (HCl) and 1 N sulphuric acid (H2SO4) was investigated by weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy techniques. The values of activation energy and free energy of adsorption of all the compounds were calculated to investigate the mechanism of corrosion inhibition. The results of potentiodynamic polarization studies revealed that all the compounds were mixed type inhibitors and inhibit the corrosion of mild steel by blocking the active sites of the metal. The adsorption of all the compounds on mild steel surface in both the acid solutions was found to obey the Langmuir adsorption isotherm. The inhibition efficiency of the compounds was found to vary with their nature and concentration, solution temperature, immersion time and acid concentrations.

Keywords: Gemini surfactants, Mild steel, Potentiodynamic polarization, Electrochemical impedance spectroscopy, Adsorption

IPC Code (s): C23F11/00

 

Indian Journal of Chemical Technology

Vol. 14, September 2007, pp. 501-506

 

Corrosion inhibition of N80 steel in hydrochloric acid by phenol derivatives

S Vishwanatham* & Nilesh Haldar

 

The inhibitory action of methoxy phenol (MPH) and nonyl phenol (NPH) on corrosion of N80 steel in 15% HCl has been investigated at different period of exposure (6 to 24 h) and temperature (30 to 110°C). Nonyl phenol and methoxy phenol have shown maximum inhibition of about 83 and 78% at 75 mM inhibitor concentration in the acid respectively after 6 h exposure test at ambient temperature. The inhibition efficiencies of nonyl phenol and methoxy phenol are found to be about 79 and 30% respectively after 24 h exposure. Nonyl phenol has shown maximum inhibition of about 59 and 44% at 75 mM inhibitor concentration in the acid respectively at 90 and 110° C respectively. The inhibition afforded by methoxy phenol was found to be relatively low (about 34% at 60°C). Heat of adsorption was found to be 50 KJ/mol in case of MPH, indicating formation of a protective chemisorbed film on the metal surface, which suppresses the dissolution reaction. NPH showed heat of adsorption of about 26 KJ/mol indicating a weak chemisorption. Both these compounds inhibit corrosion by adsorption mechanism and follow Temkin isotherm. The results of polarization studies indicate that the compounds are mixed type inhibitors. The FTIR spectral analyses of the surface product suggest involvement of hydroxyl group (un protonated as well as protonated) of these inhibitor molecules in the adsorption process.

Keywords: Steel, Phenol, Corrosion inhibition

IPC Code (s): C23F11/00

 

Indian Journal of Chemical Technology

Vol. 14, September 2007, pp. 507-514

 

Removal of copper from water samples by sorption onto powdered limestone

 

S E Ghazy* & A H Ragaba

 

The present paper describes the results of a study concerning Cu(II) removal from aqueous systems by batch adsorption experiments, using fine powdered Limestone (LS) as an effective sorbent, which is widespread and cheap. The parameters (i.e., initial solution pH, sorbent and copper concentrations, stirring times and temperature) influencing the sorption process, in addition to the effect of some foreign ions, were investigated. The results obtained showed that the sorption of Cu2+ ions onto LS is exothermic and spontaneous in nature, and followed first-order kinetics. The adsorption data were well described by Langmuir, Freundlich, Dubinin-Radushkevich (D-R) adsorption models over the concentration range studied. Under the optimum experimental conditions employed, the removal of ca. 100% of Cu2+ ions was attained. The procedure was successfully applied to the removal of copper from aqueous and different natural water samples. The adsorption mechanism is also suggested.

Keywords: Sorption, Kinetics, Langmuir, Dubinin-Radushkevich, Freundlich, Copper, Limestone

IPC Code (s): G01N33/18, B01D15/00

 

 

Indian Journal of Chemical Technology

Vol. 14, September 2007, pp. 515-522

 

Effect of monomer feed rate on the properties of copolymer butyl acrylate/vinyl acetate in semi-batch emulsion polymerization

 

M S A Palma

 

In this work, the effects of the pre-emulsion feed rate on the instantaneous and overall conversion, average particle diameter, particle size distribution, polymer particle concentration, polymerization rate, average number of radicals per particle, viscosity and coagulum of a 65 wt% total solid contents of butyl acrylate/vinyl acetate copolymer latexes during relevant emulsion polymerization over pre-emulsion feeding times of 1, 2, 3, 4 and 6 h were investigated. The temperature of reaction was maintained at 85° C during the feed input and at 90° C for 1 h after the end of the feed. The effect was quite significant for feeding times of 1 to 3 h and it was of minor significance for feeding times varying from 3 to 6 h for the conversion, average particle diameter and polymer particle concentration. The polymerization rate was influenced by the feeding time, while the particle size distribution was not affected by the feeding time. The viscosity and average number of radicals per particle exhibited a clear tendency of inversion at the critical feeding time of 3 h. The coagulum formation decreased with feeding time up to 4 h and increased drastically for 6 h.

Keywords: Co-polymerization, Vinyl acetate, Emulsion polymerization

IPC Code (s): C08F2/00

 

Indian Journal of Chemical Technology

Vol. 14, September 2007, pp. 523-525

 

Development and validation of spectrophotometric method for estimation of anti-asthmatic drug doxofylline in bulk and pharmaceutical formulation

 

M M Kamila, N Mondal & L K Ghosh*

 

A simple, sensitive and accurate UV spectrophotometric method has been developed for the determination of an anti-asthmatic drug, doxofylline, in raw material and in tablets. The drug showed maximum absorption at 272 nm in water. Beer’s law was obeyed in the concentration range 5-50 μg mL-1 of drug with an apparent molar absorptivity and Sandell sensitivity of 6.2 ´ 103 L.mol-1cm–1 and 0.0363 μg cm–2/0.001A, respectively. The limits of detection and quantification were calculated to be 0.9623 and 2.9161 μg mL-1, respectively. The method was successfully applied to the determination of doxofylline in tablets. Results were validated statistically as per ICH guidelines. It was found that the excipients present in the commercial formulation did not interfere with the method.

Keywords: Doxofylline, UV spectrophotometry, ANOVA, ICH guidelines

 

IPC Code (s): G01J3/00, A61K

 

 

Indian Journal of Chemical Technology

Vol. 14, September 2007, pp. 526-528

 

Bioinorganic studies on Fe (II)- zidovudine (azt) complex

 

Ratnesh Das* & K S Pitre

 

The anti-HIV drug 3'-Azido-3'-deoxythymidine (Zidovudine) AZT has been quantitatively and qualitatively analysed by direct current polarographic (DCP), differential pulse polarographic (DPP) and amperometric techniques.

AZT gives a well-defined polarographic reduction wave/peak with E1/2/Ep = - 1.42/ - 1.44 V versus SCE in 0.2 M KCL at pH = 6.0 ± 0.1. Fe (II)-AZT complex has been studied both in solid and aqueous phases. The IR spectral data on the drug and its Fe (II)-complex revealed complexation through -N atom of azide group. The data showed a shift in the band due to azide group in the complex from 2170 to 2150 cm-l in case of pure drug zidovudine. Hence, a tentative structure of the complex has been suggested. Antibacterial activity of the complex has been determined using Raper's paper disc method against Escherichia coli, Salmonella typhi, Vibrio cholerae, and Diplococcus pneumoniae bacteria. Looking at its increased inhibition power against the above test pathogens, it is presumed that the complex may prove to be more potent against HIV, as compared to AZT drug.

Keywords: Bioinorganic, Anti-HIV drug, Polarography, Amperometric

IPC Code (s): A61K, A01N59/00

 

 

Indian Journal of Chemical Technology

Vol. 14, September 2007, pp. 529-531

 

Synthesis, characterization and thermal studies of boron containing phenolic and cardanolic polymers

 

Rosy Antony* & C K S Pillai

 

Boron containing phenolic and cardanolic polymers were synthesized by transesterification and further polymerization with hexamethylenetetramine. Flammability and thermal stability of these polymers were evaluated by LOI and TGA, respectively, and compared with those of conventional phenol-formaldehyde and cardanol-formaldehyde resins. The polymers showed better flame retardancy and high thermal stability. The borate esters enhance the char formation decomposition reactions with the retention of the boric oxide surface coating during high temperature exposure of the phenolic mass and thus impart flame retardancy and thermal stability.

Keywords: Cardanolic polymers, Transesterification, Borate esters, Flameretardancy, Thermal stability

IPC Code (s): C08G6/00

 

Indian Journal of Chemical Technology

Vol. 14, September 2007, pp. 532-535

 

A study of structure and properties of lightly cross-linked polyethylene, crystallized from the melt under uniaxially stretching

 

B B Acharya, S Mohanty & G S Roy*

 

 

A lightly crosslinked sample when stretched in a molten state, transformation to crystalline state first takes place from the stretched molecular chains. It is observed that this mode of crystallization produces a very unique phase structure associated with many characteristic properties which are advantageous for practical use.

Keywords: Crosslinked sample, Draw ratio, Uniaxially stretching, Polyethylene, X-ray diffraction

IPC Code (s): C08F10/02

 

 

Indian Journal of Chemical Technology

Vol. 14, September 2007, pp. 536-538

 

Biocide injection as a means of internal corrosion control of oil pipelines

 

D F Aloko & A D Mohammed*

 

This research work is aimed at investigating the effect of biocide injection in the treatment of internal corrosion of oil pipelines. In this research, carefully formulated laboratory experiments are performed on a sample of sump tank discharge from Mobil Producing Nigeria (MPN) offshore facilities using formaldehyde (methanol) as the biocide. This is to assess its effect on bacterial proliferation as well as hydrogen sulphide (H2S) formation, under both aerobic and anaerobic conditions. The result from the turbidity observed in untreated cultures showed that bacterial growth had occurred in them and such growth must have been hindered by the formaldehyde in the treated aerobic and anaerobic cultures. A blackening of lead acetate paper observed with emanating rotten egg smell gas is an indication for the formation of hydrogen sulphide gas. Biocide (formaldehyde) has proved to be efficient at combating bacterial growth and hydrogen sulphide production by the bacteria. These results show that biocide can be used to prevent internal corrosion of oil pipeline since it inhibits hydrogen sulphide formation from metabolism of the bacteria.

Keywords: Corrosion, Biocide, Hydrogen sulphide, Aerobic
condition, Anaerobic condition

IPC Code (s): F16L57/00, A01N25/00