Indian Journal of Chemical Technology

VOLUME 9

NUMBER 1

JANUARY 2002

 

CONTENTS

 

Papers

 

Synthesis, spectral and electrochemical studies of novel porphyrin bound tetranuclear acyclic managanese (III) and copper (II) complexes

 

9

  G Prabusankar, G Ashok, N Sengottuvelan, D Saravanakumar, V Narayanan & M Kandaswamy

 

 

 

Studies in the thermal stability of metal dicarboxylates

16

  Esther U Ikhuoria, F E Okiemien & A I Aigbodion

 

 

 

Atomic absorption spectrometric determination of trace cadmium after preconcentration with [1-(2-pyridylazo)-naphthol]-2-naphthalene adsorbent or its complex on microcrystalline naphthalene

 

 

19

  Mohammad Ali Taher & Bal Krishan Puri

 

 

 

Studies on electrolytically generated vanadous complexes used in decontamination formulations

 

25

  J Manjanna & G Venkateswaran

 

 

 

A preliminary examination of the adsorption characteristics of Pb(II) ions using sulphurised activated carbon prepared from bagasse pith

 

32

  K Anoop Krishnan & T S Anirudhan

 

 

 

Grafting vinyl monomers onto silk fibres: Graft copolymerization of methyl-methacrylate (MMA) onto – Antheraea assama silk fibre

 

41

  A M Das & C N Saikia

 

 

 

Determination of 2-chloro and 4-chloroethylbenzene in 3-chloroethylbenzene by gas chromatography

 

47

  Amruta S Tambe

 

 

 

A novel method for cleaning reaction vessels

50

  C I Round, M M N Gibbons, C D Williams, J J Cox & I D Hudson

 

 

 

Physico-chemical treatment of coke plant effluents for control of water pollution in India

 

54

  M K Ghose

 

 

 

Synthesis and dissolution of chromium substituted magnetities in V(II)-EDTA formulation

 

60

  J Manjanna, G Venkateswaran, B S Sherigara & P V Nayak

 

 

 

 

 

Influence of anions on corrosion inhibition and hydrogen permeation through mild steel in acidic solutions in the presence of p-tolyl thiourea

 

68

   S Muralidharan, K Madhavan, S Karthikeyan & S Venkatakrishna Iyer

 

 

 

Mild steel  deterioration with time in various aqueous salt solutions

74

   Rita Mehra & Aditi Soni

 

 

 

Educator                                                                                                              

 

The Dead Sea¾A live pool of chemicals

79

   Jaime Wisniak

 

 

 

 

 

 

Indian Journal of Chemical Technology

Vol. 9, January 2002, pp. 9-15

 

Synthesis, spectral and electrochemical studies of novel porphyrin bound tetranuclear acyclic manganese(III)
and copper(II) complexes

 

G Prabusankar, G Ashok, N Sengottuvelan, D Saravanakumar, V Narayanan* & M Kandaswamy*

Department of Inorganic Chemistry, University of Madras, Guindy Campus, Chennai 600 025, India

Received 27 December 2000; revised 12 October 2001; accepted 20 November 2001

The tetranucleating manganese(III) and copper(II) complexes of the type Mn4LP2, Cu4LP2, where H6LP2= 1,4 bis[2¢-hydroxy-3¢-(iminotetraphenylporphyrin)-5¢-methylbenzyl]piperazine, were synthesized and characterized. Mn4LP2 complex is EPR silent and this indicates that manganese is in +3 oxidation state. Cu4LP2 complex showS broad band with g value centered at 2.06 indicates antiferromagnetic coupling. Cyclic voltammetry studies indicating that the Mn4LP2 complex undergoes quasireversible electron transfer in the cathodic potential region and irreversible electron transfer in the anodic potential region. Cu4LP2 complex undergoes irreversible electron transfer in the cathodic potential region, quasireversible electron transfer in the anodic potential region.

 

Indian Journal of Chemical Technology

Vol. 9, January 2002, pp. 16-18

 

Studies in the thermal stability of metal dicarboxylates

 

Esther U Ikhuoriaa*, F E Okiemiena & A I Aigbodionb

aUniversity of Benin, Department of Chemistry, Benin City

bRubber Research Institute, End-use Division, P.M.B. 1049, Benin City

Received 8 August 2001; revised 2 November 2001; accepted 20 November 2001

Cadmium adipate and cadmium oxalate suitable for use as stabilizer for vinyl polymers were prepared by metathesis in aqueous alcohol solutions. The thermal stability of the carboxylates was measured gravimetrically at 443, 453 and 463K. Both cadmium adipate and cadmium oxalate showed less than 20% in weight indicating that they are relatively stable within this temperature range. Kinetic studies of the thermal decomposition of the dicarboxylates showed that the initial rate constant for the decomposition of cadmium adipate is higher than that of cadmium oxalate and they are of the order of magnitude of 10–2 min-1. The enthalpy, entropy and free energy of activation for the decomposition of the metal dicarboxylates were also determined.

 

Indian Journal of Chemical Technology

Vol. 9, January 2002, pp. 19-24

 

Atomic absorption spectrometric determination of trace cadmium after preconcentration with [1-(2-pyridylazo)-
2-naphthol]-naphthalene adsorbent or its complex on microcrystalline naphthalene

Mohammad Ali Tahera & Bal Krishan Puri*

aDepartment of Chemistry, Shahid Bahonar University, Kerman, Iran
* Department of Chemistry, Indian Institute of Technology, Hauz Khas, New Delhi 110 016, India

Received 18 December 2000; revised 29 October 2001; accepted 9 November 2001

Cadmium 1-(2-pyridylazo)-2-naphthol complex is quantitatively adsorbed on microcrystalline naphthalene in the pH range 8.0-10.5. It can also be alternatively adsorbed on [1-(2-pyridylazo)-2-naphthol]-naphthalene adsorbent packed in a column at a flow rate of 1-2 mL/min and the metal determined by flame atomic absorption spectrometrically by measuring the absorbance at 228.8 nm against a reagent blank. About 0.05 mg of cadmium can be concentrated in a column from 450 mL of aqueous sample, where its concentration is as low as 0.11 ng/mL. The detection limit is 44 pg/mL for cadmium at the minimum instrumental settings. The linearity is maintained in the concentration range 0.11 ng/mL to 0.4 μg/mL cadmium in aqueous solution or 0.01 to 1.6 μg/mL cadmium in the final DMF solution with a correlation factor of 0.9995. Eight replicate determinations of 0.3 mg/mL of cadmium in final DMF solution give a mean absorbance of 0.150 with a relative standard deviation of 1.6%. The sensitivity for 1% absorption is 8.8 ng/mL in final DMF solution. The interference of a large number of anions and cations on the determination of cadmium after the preconcentration step have been studied and the optimized conditions developed utilized for its trace determination in various alloys and biological samples. The method may also be used for the determination of cadmium in various environmental samples.

 

Indian Journal of Chemical Technology

Vol. 9, January 2002, pp. 25-31

 

 

 

Studies on electrolytically generated vanadous complexes used in
decontamination formulations

J Manjannaa & G Venkateswaranb*

aDepartment of Industrial Chemistry, Kuvempu University, Shimoga 577 451, India

bApplied Chemistry Division, BARC, Trombay, Mumbai 400 085, India

Received 27 September 2000; revised 10 November 2001; accepted 15 November 2001

The low oxidation state metal ion, V2+ being a strong reducing agent can be formulated/complexed with suitable chelating agents to obtain a significant dissolution (reductive) of iron oxides, commonly found on the primary system surfaces (iron base alloys) of water-cooled nuclear reactors. The relative strength of the complexes of V2+ (as formate) with different chelating agents, L such as picolinic acid, EDTA and citric acid is studied by measurements of redox potential and UV-Visible spectra. The decay kinetics of the reduction of water by V(II)-picolinate (as a typical case) (V2+ to V3+ conversion) under deaerated condition was estimated using redox potential values and decay was found to follow two stages of first order kinetics with a faster initial stage (k1=3.45´10-3 min-1) and a slower second stage (k2=3.84´10-4 min-1). The cation and anion exchange resin behaviour of the complexes/formulations in their different oxidation states with their derived species is reported and the V(III)-picolinate is shown to exist as an anionic species in formate medium. The use of V(II)-EDTA and V(II)-citrate for dissolution has an advantage as their oxidation (to V(III) stage) at higher concentration ca. >7mM has not resulted in any precipitation/crystallization unlike in the case of V(II)-picolinate.

 

 

 

Indian Journal of Chemical Technology

Vol. 9, January 2002, pp. 32-40

 

 

A preliminary examination of the adsorption characteristics of Pb(II) ions using sulphurised activated carbon prepared from bagasse pith

 

K Anoop Krishnan & T S Anirudhan<

Department of Chemistry, University of Kerala, Kariavattom, Trivandrum 695 581, India

Received 30 December 2000; revised 12 November 2001; accepted 20 November 2001

Bagasse pith, a sugar industry waste, has been converted into sulphurised activated carbon by carbonisation at 200°C under N2 for 2h, followed by steam activation in presence of SO2 and H2S at 400°C for 2h. The adsorption characteristics of Pb(II) ions on activated carbon have been examined from aqueous solutions using batch technique. The effect of agitation period, initial concentration of sorbate, pH, ionic strength, temperature and particle size of the adsorbent has been studied to optimise the conditions for maximum removal of Pb(II) ions. The maximum removal takes place in the pH range of 4.0-8.0. With an initial concentration of Pb(II) at 50 mg/L at 30°C and pH 6.0, its removal has been found to be 99.8 %. The process of uptake is governed by a pseudo-second-order kinetics. Kinetic parameters as a function of initial concentration and temperature have been calculated. Decrease in ionic strength and increase in temperature of the solution has been found to improve the uptake of Pb(II). Studies show that the adsorption decreases with an increase in particle size of the adsorbent. Sorption data of Pb(II) in the concentration range 50-1000 mg/L have been correlated with Langmuir isotherm model. Sulphurised activated carbon had adsorption capacities for Pb(II) from 200.08 mg/g at 30°C to 243.93 mg/g at 60°C, which is much higher than the values for the adsorbent materials reported in the literature. The adsorbent has been satisfactorily used for the removal of Pb(II) from synthetic wastewaters. The adsorbed Pb(II) ions are completely recovered with 0.2 M HCl.

 

 

Indian Journal of Chemical Technology

Vol. 9, January 2002, pp. 41-46

 

 

Grafting vinyl monomers onto silk fibres : Graft copolymerization of methylmethacrylate (MMA)
onto - Antheraea assama silk fibre

A M Das & C N Saikia*

Cellulose Pulp and Paper Division, Regional Research Laboratory, Jorhat 785 006, India

Received 17 January 2001; revised 14 May 2001; accepted 6 June 2001

Graft copolymerization of methylmethacrylate (MMA) onto non-mulberry silk fibre Antheraea assama was carried out in aqueous medium using KMnO4-oxalic acid redox initiator. The rate of grafting (%) was evaluated as a function of initiator (oxalic acid) and H2SO4 acid concentrations, reaction temperature and time. The rate of grafting increased progressively with the increase of oxalic acid and H2SO4 concentrations up to 1.25´10-2 and 16´10-2 mol/L respectively. The extent of grafting (%) depends upon reaction time and temperature also. The grafted products were characterized with the help of infra-red (IR) spectroscopy, while the thermal decompositions of the ungrafted and grafted silk fibres were studied using TGA, DTG and DTA techniques at two heating rates 20ºC and 30ºC min-1 in static air in the temperature range 30-800ºC. The grafted products were found to be thermally more stable than the ungrafted ones. The water retention values (WRV) of the grafted fibres were in decreasing order with the increase in grafting (%).

 

 

 

Indian Journal of Chemical Technology

Vol. 9, January 2002, pp. 47-49

 

 

 

Determination of 2-chloro and 4-chloroethylbenzene in 3-chloroethylbenzene by gas chromatography

 

Amruta S Tambe*

Division of Organic Chemistry: Technology, National Chemical Laboratory, Pune 411 008, India

Received 31 October 2000; revised 30 October 2001; accepted 9 November 2001

An efficient and rapid gas chromatographic method has been developed for the analysis of 2-chloro, 3-chloro, and 4-chloroethylbenzene isomers using 25 meter, 320 micron BP-20 polyamide coated fused silica capillary column. Quantitative analysis has been carried out using the external standard method. Also, the minimum detectable amount of 4-chloroethylbenzene has been established.

 

 

Indian Journal of Chemical Technology

Vol. 9, January 2002, pp. 50-53

 

 

 

A novel method for cleaning reaction vessels

 

C I Rounda, M M N Gibbonsb, C D Williams, J J Cox & I D Hudsonc

aSchool of Applied Sciences, University of Wolverhampton, Wulfruna Street, Wolverhampton, WV1 1SB

bSchool of Chemistry, University of Surrey, Guildford, Surrey, GU2 5XH

cResearch and Technology, BNFL, Springfields, Preston, Lancashire, PR4 0XJ

Received 11 January 2001; revised 5 November 2001; accepted 15 November 2001

The objective of zeolite synthesis is the production of pure phase material and a study by Lowe et al.1 showed that small and possibly significant amounts of template remaining in supposedly clean vessels could influence the crystallisation of subsequent gels. Two cleaning methods are widely used to clean the synthesis reaction vessels i.e. hydrofluoric acid or a solution of sodium hydroxide at reaction temperature, but their efficacy has not been tested. Zeolite omega was synthesized with both organic and inorganic templates and, following synthesis, the reaction vessels were cleaned by a novel method, described here, using hydrofluoric acid, crown ethers, and ultrapure water. This new method was compared to the standard methods by using a ‘scavenging gel’1 to test the cleanliness of the vessels. The ‘scavenging gel’ produced some crystalline material when used following conventional cleaning whereas, when the vessels were cleaned using the method described here, the gel failed to crystallise. Conductivity measurements have proved a reliable index to the cleanliness of the reaction vessels.

 

Indian Journal of Chemical Technology

Vol. 9, January 2002, pp. 54-59

 

 

Physico-chemical treatment of coke plant effluents
for control of water pollution in India

M K Ghose*

Centre of Mining Environment, Indian School of Mines, Dhanbad 826 004, India

Received 31st July 2000;revised 19 June 2001; accepted 26 September 2001

Coal carbonizing industries in India are important and are growing every year. Naturally found coal is converted to coke which is suitable for metallurgical industries. Large quantities of liquid effluents produced in this industry contain a large amount of suspended solids, high biochemical oxygen demand (BOD), chemical oxygen demand (COD), phenols, ammonia and other toxic substances, which are causing serious surface water pollution in the area. There is a large number of coke plants in the vicinity of Jharia Coal Field (JCF). Working principle of coke plant and the effluents produced has been described in this paper. One large coke plant was chosen to evaluate characteristics of the effluent and to suggest a proper treatment method. Present effluent treatment system was not found to be adequate and a large quantity of a very good quality coke breeze is being lost, which is also causing siltation on the riverbed in addition to surface water pollution. Physico-chemical treatment has been considered as a suitable option for the treatment of coke plant effluents. A scheme has been proposed for the treatment, which can be suitably adopted for the recycling, reuse or safe disposal of the treated effluent. Various unit process and unit operations have been discussed. The process may be useful on industrial scale for various sites so as to maintain a clean environment.

 

 

Indian Journal of Chemical Technology

Vol. 9, January 2002, pp. 60-67

 

 

 

Synthesis and dissolution of chromium substituted magnetites in V(II)-EDTA formulation

 

J Manjannaa, G Venkateswaranb*, B S Sherigaraa & P V Nayaka

aDepartment of Industrial Chemistry, Kuvempu University, Shimoga 577 451, India

bApplied Chemistry Division, BARC, Trombay, Mumbai 400 085, India

Received 20 September 2000; revised 10 November 2001; accepted 15 November 2001

Chemical cleaning or scale removal of boilers, heat exchangers etc., involves the dissolution of metal oxides, which are corrosion products from the base metal. Iron oxides mainly hematites and magnetites are commonly found in the case of Fe based alloys due to corrosion. The decontamination of primary system surface of water-cooled nuclear reactors, in particular Pressurized Light Water Reactor (PWR)/ Pressurized Heavy Water Reactor (PHWR) involves the dissolution of iron oxides formed under reducing coolant chemistry environment ca. magnetite type of oxide matrix. Thus in the present study, the dissolution characteristics of Cr-substituted (0-20 at% Cr) magnetites (c.s.m) in V(II)-EDTA formulation at 353±5 K are reported. The oxides employed were prepared synthetically by co-precipitation method, moderately sintered and physico-chemically characterized. The dissolution rate coefficient, k1 and the percentage of dissolution were determined. The oxidative pre-treatment of these oxides employing viz., AP, NP and HMnO4 had resulted in improved dissolution.

 

 

 

Indian Journal of Chemical Technology

Vol. 9, January 2002, pp. 68-73

 

 

 

Influence of anions on corrosion inhibition and hydrogen permeation through mild steel in acidic solutions in the presence of p-tolyl thiourea

                                                                                                                                                          

S Muralidharana*, K Madhavanb, S Karthikeyanc & S Venkatakrishna Iyera

aCentral Electrochemical Research Institute, Karaikudi 630 006, India

bAlagappa Government Arts College, Karaikudi 630 003, India

cDepartment of Industrial Chemistry, Alagappa University, Karaikudi 630 003, India

Received 10 January 2001; revised 3 October 2001; accepted 9 October 2001

The influence of anions such as chloride and sulphate on the inhibition of corrosion of mild steel by p-tolyl thiourea (PTTU) in 1N HCl and 1N H2SO4 has been studied using weight loss and gasometric measurements, galvanostatic polarisation studies and ac impedance measurements. The compound is found to be less inhibitive in 1N HCl than in 1N H2SO4. The influence of p-tolyl thiourea on the extent of hydrogen permeated through mild steel in acidic solutions has been studied using electro-permeation technique. The compound is found to enhance the permeation of hydrogen through mild steel in both the acids. The adsorption of p-tolyl thiourea on the mild steel surface from both the acids obeys Temkin’s adsorption isotherm. The increase of charge transfer resistance (Rt) and decrease in double layer capacitance (Cdl) values of the metal electrode in the presence of the test compound (PTTU) show the adsorption of the compound on the metal surface.

 

 

Indian Journal of Chemical Technology

Vol. 9, January 2002, pp. 74-78

 

 

 

Mild steel deterioration with time in various aqueous salt solutions

Rita Mehra* & Aditi Soni

Department of Applied Chemistry, Maharshi Dayanand Saraswati University  Ajmer 305 009, India

Received 7 November 2000; revised 25 May 2001; accepted 23 June 2001

The corrosivity of water supplies need to be  evaluated in view of the aesthetic problems in water and also because of the potential public health importance. As such, some recent work on mild steel deterioration has been carried out. The results assessed from weight loss measurements for different chemical mediums support the chloride aggressiveness reported in literature. But the relative behaviour of other ions vary with time being lesser in concentration as per potable water quality standards. Potentiostatic polarisation results have also been carried out to determine the effect of different anions and time on corrosion rate through changes in potential. The corrosion potential (Ecorr.), corrosion current (Icorr.), Tafel slopes, corrosion rate have been obtained from polarisation experiments  using a three electrode set-up. For reliability of results, the data has  been  statistically analysed.

 

 

Indian Journal of Chemical Technology

Vol. 9, January 2002, pp. 79-87

 

 

 

The Dead Sea—A live pool of chemicals

Jaime Wisniak*

Department of Chemical Engineering, Ben-Gurion University of the Negev, Beer-Sheva, Israel 84105

The Dead Sea has been a source of chemicals since ancient times. Large scale production of potash by solar evaporation started in 1931 and today the Dead Sea is intensively exploited by Israel and Jordan as a major source of potash, bromine, and magnesium, for agriculture and the chemical and automotive industries. A smart coupling of solar evaporation and knowledge of the complex phase diagram allows a one-to-one easy separation of the principal salts present in the brine. A description of the properties of the Dead Sea is provided together with a chemical engineering analysis of the processes used to realize its commercial potential.