Indian Journal of Chemical Technology

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VOLUME 17

NUMBER 6

NOVEMBER 2010

CODEN:ICHTEU

 

ISSN:0971-457X

 

CONTENTS

 

Papers

 

 

 

Evaluation of porous nickel hydroxide electrode for the oxidation of aliphatic

 

and aromatic primary alcohols

411

T Vijayabarathi, K Vijayarani & M Noel

 

 

 

Corrosion behaviour of sol-gel Al2O3 coated Al-Si alloy in 3.5% NaCl solution

419

I B Singh, M Singh, S Das & A H Yegneswaran

 

 

 

Inhibition of mild steel corrosion in 1 M hydrochloric acid using (E)-4-(2-chlorobenzylideneamino)- 6-methyl-3-thioxo-3,4-dihydro-1,2,4-triazin-5(2H)-one (CBMTDT)

 

425

Bincy Joseph, Sam John, K K Aravindakshan & Abraham Joseph

 

 

 

Absorption of carbon dioxide into a mixed aqueous solution of diethanolamine and piperazine

431

M K Mondal

 

 

 

Solvent extraction and separation of Mo(VI) and W(VI) from hydrochloric acid solutions using cyanex-923 as extractant

 

436

R G Talla, S U Gaikwad & S D Pawar

 

 

 

Extraction of acetic acid from aqueous solutions by emulsion type liquid membranes using Alamine 300 as a carrier

 

441

Aynur Manzak & Melek Sonmezoglu

 

 

 

A comparative study on basicity based on supported K-salt catalysts for isomerization of 1-methoxy- 4-(2-propene-1-yl) benzene

 

446

Baldev Singh, Jyoti Patial, Parveen Sharma, Suresh Chandra, Sudip Maity & N Lingaiah

 

 

 

Oxidation of phenol using LaMnO3 perovskite, TiO2, H2O2 and UV radiation

451

Chandrakant Singh & Meeta Rakesh

 

 

 

Comminution behaviour of microwave heated two sulphide copper ores

455

Erol Kaya

 

 

 

Conductometric studies on salvation behaviour of citric acid in water + methanol and water + ethanol mixtures at different temperatures

 

462

J Ishwara Bhat & M N Manjunatha

 

 

 

 

Note

 

 

 

Determination of boron in zirconium-niobium alloys by spectrophotometry

468

P S Ramanjaneyulu, Y S Sayi & K L Ramakumar

 

 

 

Acknowledgement to Reviewers

471

 

 

Annual Author Index

473

 

 

Annual Keyword Index

475

 

 

Guidelines for Authors

479

 

 

Indian Journal of Chemical Technology

Vol.17, November 2010, pp. 411-418

 

Evaluation of porous nickel hydroxide electrode for the oxidation of aliphatic and aromatic primary alcohols

T Vijayabarathi, K Vijayarani & M Noel

The positive plate of Ni-Cd battery was evaluated as Ni(OH)2/NiOOH electrode for the oxidation of six aromatic and five aliphatic alcohols. In addition to galvanostatic preparative electrolysis, cyclic voltammetric experiments were also carried out. The anode material after electrolysis was evaluated using SEM and XRD. Except in the case of chlorine substituted aromatic alcohols the nickel hydroxide electrode showed excellent stability even after the reuse for nearly 10-15 times. In 0.1 M KOH containing 67% tertiary butanol + 33% water as electrolyte, aromatic alcohols gave predominantly aldehyde in good yield. In alkaline solutions without the co-solvent tertiary butanol aromatic alcohols were oxidized to their corresponding carboxylic acids. Short chain aliphatic alcohol (C5) gave reasonable yield of carboxylic acid. Long chain alcohols showed limited solubility in alkaline medium with and without co-solvent tertiary butanol and the yields of carboxylic acids were also poor.

Keywords: Alcohols, Catalytic activity, Porous nickel hydroxide electrode, Oxidation, Voltammetry

 

 

 

Indian Journal of Chemical Technology

Vol. 17, November 2010, pp. 419-424

 

 

Corrosion behaviour of sol-gel Al2O3 coated Al-Si alloy in 3.5% NaCl solution

I B Singh, M Singh, S Das & A H Yegneswaran

Alumina sol was synthesised and coated on Al-Si alloy. The coated substrates were heated at 300C for sintering and precursor removal purposes. The cross sectional examination of the coated specimens in SEM showed the presence of around 7 μm thick non porous and compact coating. XRD analysis confirmed the presence of αAl2O3 in the coated layer. The corrosion characteristics of the coating were evaluated in 3.5% NaCl solution by electrochemical measurements. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) analysis indicated that the coated substrate possesses an order of magnitude higher corrosion resistance as compared to uncoated substrate. EIS study has also indicated a significant decrease in diffusion phenomena of chloride ions through the coating/metal interfaces. The effect of heat treatment of Al-Si alloy on its corrosion properties has also been investigated.

 

Keywords: Al-Si alloy, Composite, Alumina coating, Sol-gel process, Corrosion

 

 

Indian Journal of Chemical Technology

Vol. 17, November 2010, pp. 425-430

 

Inhibition of mild steel corrosion in 1 M hydrochloric acid using (E)-4-(2-chlorobenzylideneamino)-6-methyl-3-thioxo-3,4-dihydro-1,2,4-triazin-5(2H)-one (CBMTDT)

Bincy Joseph, Sam John, K K Aravindakshan & Abraham Joseph

The use of nitrogen and sulphur donor organic inhibitors in acid solutions is a common method for the protection of metals from corrosion. The present work is the study of the corrosion inhibition efficiency of (E)-4-(2-chlorobenzylideneamino)-6-methyl-3-thioxo-3,4-dihydro-1,2,4-triazin-5(2H)-one (CBMTDT) towards mild steel in 1 M HCl. The work strategy includes the conventional weight loss method, potentiodynamic polarization studies (Tafel), linear polarization studies (LPR), electrochemical impedance spectroscopy (EIS), adsorption studies and quantum chemical calculations. Results showed that the corrosion rate decreases and inhibition efficiency increases with inhibitor concentration. The results of polarization studies reveal that the additive acts as a mixed type inhibitor. The surface adsorption of the inhibitor molecules decreases the double layer capacitance and increases the polarization resistance. The adsorption process is spontaneous and follows Langmuir adsorption isotherm model. The optimized structure of the inhibitor, energies of LUMO, HOMO and other physical parameters are calculated by computational quantum chemical methods.

 

Keywords: Corrosion, Mild steel, Electrochemical impedence, Potentiodynamic polarization, CBMTDT

 

Indian Journal of Chemical Technology

Vol. 17, November 2010, pp. 431-435

Absorption of carbon dioxide into a mixed aqueous solution of diethanolamine and piperazine

M K Mondal

The CO2 loading in aqueous mixtures of diethanolamine (DEA) and piperazine(PZ), from a mixture of CO2 and N2, has been measured for total amine concentrations and mole ratios of PZ to total amine ranging from 2.0 to 3.0 M and 0.01 to 0.20, respectively, at 313.14 K and 15.199 kPa CO2 partial pressure. Measurements were made by a saturation method using a laboratory scale bubble column. The results of CO2 loading are expressed as XCO2 (mole CO2 /mole of total amine) for all experimental runs. A model is given to predict the CO2 loading in aqueous mixture of DEA and PZ. The model predictions have been in good agreement with the experimental data of CO2 loading in aqueous mixture of DEA and PZ with the average deviation of 8.67.

 

Keywords: DEA, PZ, CO2 Loading, Total amine, Bubble column

 

 

Indian Journal of Chemical Technology

Vol. 17, November 2010, pp. 436-440

 

Solvent extraction and separation of Mo(VI) and W(VI) from hydrochloric acid solutions using cyanex-923 as extractant

R G Talla, S U Gaikwad & S D Pawar

A systematic study of solvent extraction of molybdenum(VI) and tungsten(VI) from hydrochloric acid media using neutral phosphine oxide extractant, cyanex-923 in toluene has been performed. These metal ions are quantitatively extracted with cyanex-923 in toluene in the acidic range 5-7 M, and from the organic phase they are stripped with 1.0 M NaOH. The effect of pH, equilibrium period, diluents, diverse ions and stripping agent on the extraction of Mo(VI) and W(VI) has been studied. The extraction reactions proceed by solvation and the probable extracted species in the organic phase were MoO2Cl2.2Cyanex-923 and WO2Cl2.2Cyanex-923. Based on these results a sequential procedure for their separation from each other has been developed.

Keywords: Solvent extraction, Molybdenum(VI), Tungsten(VI), Cyanex-923, Stripping, Separation

 

 

 

Indian Journal of Chemical Technology

Vol. 17, November 2010, pp. 441-445

 

Extraction of acetic acid from aqueous solutions by emulsion type liquid membranes using Alamine 300 as a carrier

Aynur Manzak & Melek Sonmezoglu

The extraction of acetic acid from aqueous solutions by an emulsion type liquid membrane process was investigated, using Alamine 300 as carrier, Span 80 as surfactant, and Na2CO3 solution as stripping agent. A number of significant parameters viz. mixing speed, surfactant concentration, diluent type, concentration of the carrier Alamine 300, concentration of stripping agent, pH and concentration of feed solution were investigated. Acetic acid was successfully extracted and concentrated from aqueous solutions. Approximately 86% extraction of acetic acid was achieved within 10 min in a stirred vessel.

Keywords: Acetic acid extraction, Alamine 300, Emulsion liquid membrane, Surfactant, Diluent

 

 

Indian Journal of Chemical Technology

Vol.17, November 2010, pp. 446-450

 

A comparative study on basicity based on supported K-salt catalyst for isomerization of 1-methoxy-4-(2-propene-1-yl) benzene

Baldev Singh, Jyoti Patial, Parveen Sharma, Suresh Chandra, Sudip Maity & N Lingaiah

A comparative study on basicity of supported K-salt catalysts has been carried out for the preparation of trans-anethole [1-methoxy-4-(1-propen-1-yl) benzene]. It is observed that strong basic sites facilitated 99% conversion of methyl chavicol [1-methoxy-4-(2-propen-1-yl) benzene] with 89% selectivity of trans-anethole. Activation energy for isomerization of methyl chavicol was found to be in the range of 5.65 8.67 kJ/mol using 25% K2CO3 loaded on alumina. The catalysts were characterized by CO2-TPD and BET surface area.

Keywords: Methyl chavicol, Trans-anethole, Basicity, Isomerization

Indian Journal of Chemical Technology

Vol. 17, November 2010, pp. 451-454

 

Oxidation of phenol using LaMnO3 perovskite, TiO2, H2O2 and UV radiation

Chandrakant Singh & Meeta Rakesh

LaMnO3 perovskite has been used for the treatment of aqueous solution of phenol using stoichiometric amount of H2O2 and combination of TiO2 and UV radiation. The oxidation of phenol was studied with [UV radiation];
[H2O2 and UV]; [TiO2 and UV]; [LaMnO3 and UV]; [TiO2, H2O2 and UV]; [LaMnO3, H2O2 and UV]; to establish the effectiveness of different systems when compared with perovskite catalyst. Results show that the phenol degradation efficiencies decreased in the following order [LaMnO3, H2O2 and UV] > [TiO2, H2O2 and UV] > [LaMnO3 and UV] > [TiO2 and UV]> [H2O2 and UV ] > [UV]. UV-VIS spectra result of phenol degradation shows that as the concentration of catalyst increases, its activity increases. The optimum concentration of catalyst was 0.60 g/L for 100 ppm phenol solution. Perovskite catalyst after reaction is completely regenerated by calcinations at 800C for 2 h and retains a similar catalytic performance.

Keywords: Perovskite, Phenol, Hydrogen peroxide, Photochemical reactor, AOPs

 

 

Indian Journal of Chemical Technology

Vol. 17, November 2010, pp. 455-461

 

Comminution behaviour of microwave heated two sulphide copper ores

 

Erol Kaya

The effect of microwave irradiation on the comminution of two sulphide copper ores with different mineralogy were investigated to enhance the milling processes. Each ore was subjected to microwave radiation for varying time periods to determine their heating profiles. Changes in breakage characteristics with the microwave exposure time were quantified by sieving breakage, standard Bond work index grindability and single particle drop weight comminution tests. The results of the sieving breakage tests with the untreated and microwaved samples indicated significant improvements in the size reduction due to microwave energy induced macro fracturing. Differing ore mineralogy has been shown to affect the effectiveness of microwave assisted size reduction. The results of the standard Bond work index grindability tests performed with both the microwave treated copper ores, on the other hand, suggested no significant improvements in grindability. The single particle fracture experiments performed with an Ultrafast Load Cell (UFLC) indicated similar results of no significant improvements in the fracture energies of the microwave treated ore samples.

 

Keywords: Microwave irradiation, Comminution, Copper ore

Indian Journal of Chemical Technology

Vol.17, November 2010, pp. 462-467

 

 

Conductometric studies on solvation behaviour of citric acid in water + methanol and water + ethanol mixtures at different temperatures

J Ishwara Bhat & M N Manjunatha

The paper reports the study on the effect of solvation of the species of citric acid in water + methanol and water + ethanol mixtures (v/v) on its conductivity behaviour as a function of temperature. The specific conductance was measured in the temperature range 283-313 K and the evaluated equivalent conductance was analyzed by Kraus-Bray and Shedlovsky models of conductivity. Limiting molar conductance (λ0m), dissociation constant (KC) and association constant (Ka) were evaluated for all solvent compositions. The limiting molar conductance was found to decrease with the increase in amount of co-solvent to water. Kc increased with increase in temperature till 60% methanol and 40% ethanol with a later decrease. Fuoss Accascina equation was applied and it was proved that the formation of ion pairs and scanty amount of ion triplets takes place in the system. Walden product, corrected Stokes radius (ri), thermodynamic parameters and solvation number also have been evaluated. Born relation of solvation was verified. These data were used to study the nature of ion-solvent and solvent-solvent interactions existing in the system under prevailing conditions.

Keywords: Solvation behaviour, Specific conductance, Citric acid

Indian Journal of Chemical Technology

Vol. 17, November 2010, pp. 468-470

 

Determination of boron in zirconium-niobium alloys by spectrophotometry

P S Ramanjaneyulu, Y S Sayi & K L Ramakumar

Boron doped zirconium-niobium alloy rods are used as neutron reactivity control rods in advanced nuclear reactors. Accurate knowledge about the boron content in this alloy is an essential requirement prior to its usage in nuclear reactors. In view of the refractory nature of the alloy, boron determination in these type of matrices is a challenging task. Also due to non-availability of matrix matched reference materials, direct solid analysis cannot be resorted to. Quantitative dissolution of the matrix without losing any boron followed by its determination is the only alternative. In the present work, Zr-Nb sample was dissolved in (NH4)2SO4 and H2SO4 taking care to prevent the loss of boron. Boron was selectively separated employing batch extraction with 10% 2-ethyl hexane 1,3 diol in chloroform and determined spectrophotometrically as B-Curcumin complex. Absorbance was measured at 550 nm. The precision and accuracy of the method is 3%. The absolute detection limit of the method is 12 ng. The method has been evaluated by standard addition method and validated by ICP-AES technique.

 

Keywords: Zr-Nb alloy, Boron, Spectrophotometry, Curcumin