Indian Journal of Chemical Technology

Research Articles

Removal of fluoride ion from aqueous bodies by aluminium complexed amino phosphonic acid type resins	299
IPC Code: (C02F 1/28, 101:14)
Dharmesh B Bhatt, Prashant R Bhatt, H Hari Prasad, Kirit M Popat & Pritpal Singh Anand
An efficient and reversible sorptive removal of arsenic(III) from aqueous solution by the biosorbent Cupressus Female Cone	304
IPC Code: (C02F 1/28, 101:10)
M Murugan & E Subramanian

Use of bromophenol blue in the spectrophotometric and turbidimetric determination of mebrophenhydramine in tablets	309
IPC Code: G01J 3/00, A61K 31/13
K Basavaiah & V S Charan

Studies on the chemistry of thermal drying of lignite in inert atmosphere	314
IPC Code: E 21C 41/18
Joy Mukherjee, Ms Puspa Singh & Abhijit Sarkar

Molybdenum complexes as precursors of tribologically active substances under extreme pressure conditions	317
IPC Code: C01G 39/00
R B Rastogi & M Yadav

Determination of alcohol in petrol-alcohol mixtures	323
IPC Code: G01N 9/36
G S R Sastry, P Ravi Prasad & K Bhuvaneswari

Preparation and characterization of molybdenum hydrotreating catalyst supported on MgO/Al₂O₃mixed oxide	326
IPC Code: B01J 23/28
Folorunsho Aberuagba, Manoj Kumar, Gudimella Muralidhar & Lakshmi Datt Sharma

Inhibition of mild steel corrosion in formic and acetic acid solution	331
IPC Code: C23F 11/04
M A Quraishi & H K Sharma

Alkylation of benzene with ethanol over ZSM-5 catalyst with different SiO₂/Al₂O₃ ratios	337
IPC Code: C07B 37/00
Jun-Jun Yuan & Börje S Gevert
Corrosion inhibition by caffeine ¾ Mn²⁺system	346
IPC Code: C23F 11/00
Noreen Anthony, E Malarvizhi, P Maheshwari, Susai Rajendran & N Palaniswamy
Alkylation of naphthalene with t-butanol over zeolite Y: Influence of reaction environment and reaction kinetics	351
IPC Code: C07B 37/00
R Nagotkar, S S Khaire, S Mayadevi & S Sivasanker

Studies of printing inks on starch blended and surface grafted polyethylene film for flexible packaging	357
IPC Code: C09D 11/02
R N Ghosh, B Adhikari & B C Ray
A population balance model for miniemulsion polymerization	367
IPC Code: C08F 2/22
A Sood & S K Awasthi

Influence of microwave irradiation on enzymatic activity of invertase in aqueous and organic solvents	377
IPC Code: C12N 9/26, B01J 19/08
C N Khobragade & Ganesh V Kore

Effect of flotation reagents on the wet grinding of celestite concentrate	382
IPC Code: B22F 9/00, B03D 1/001
Yakup Cebeci & Oktay Bayat

Effect of magnetic field on membrane potential	388
IPC Code: G01N 13/00
Meena Sharma & R L Blokhra

Liquid drainage in static foam: Analogy with liquid drainage through packed bed	392
IPC Code: B01D 19/02, B01J 19/10
Pankaj V Ambulgekar, Anjali C Dedhia & Aniruddha B Pandit

Vapour phase transesterification over solid acids for the synthesis of isoamyl salicylate	401
IPC Code: C07B 41/12
Joyce D’Souza & N Nagaraju

Low temperature oxidation of ethanol	410
IPC Code: C07B 33/00
S S Verma

Photocatalytic bleaching of amaranth dye over ZnO powder	423
IPC Code: C09B 61/00, G01j 1/00
Rameshwar Ameta, Nilesh Jain & Sharad Kothari
CO oxidation over Pd/g-FeMnO₃catalyst	427
IPC Code: C01B 31/18, B01J 23/54
S K Kulshreshtha, S Sharma, R Vijayalakshmi & R Sasikala

Educator
The nature and composition of water	434
Jaime Wisniak

Chem-Tech Scan	445

Author Index	449

Keywords Index	450

Removal of fluoride ion from aqueous bodies

by aluminium complexed amino phosphonic acid

type resins

Dharmesh B Bhatt, Prashant R Bhatt, H Hari Prasad, Kirit M Popat & Pritpal Singh Anand*.

Three resins, namely Purolite S940, Purolite S950 and Duolite ES 467 were studied for the removal of fluoride ion under different equilibrium conditions. The adsorption data of Purolite S940 and Purolite S950 closely fitted in Freundlich and Langmuir equations, respectively. Validity of the Lagergan equation for the sorption of fluoride ion was proved and the data showed that the process followed first order kinetics. The performance of Purolite S940 and Purolite S950 showed good promise for removing fluoride from water whereas the performance of Duolite ES467 was comparatively poor under dynamic conditions.

Keywords: Fluoride removal, Purolite S940, Purolite S950, Duolite ES467, resin, Freundlich equation, Langmuir equation, Lagergan equation

An efficient and reversible sorptive removal of

arsenic (III) from aqueous solution

by the biosorbent Cupressus Female Cone

Biosorbent Cupressus Female Cone (CFC) has been investigated for the sorptive removal of As(III) from aqueous solution both by batch and column mode techniques. Sorption process was found to be influenced appreciably by pH, temperature, initial concentration of As(III) and sorbent particle size and dosage. Also the sorption process was endothermic with a maximum sorption of 260.4 mg/g of As(III) at 30^oC for an initial concentration of 800 mg/L at pH10.0. It followed first order kinetics and the equilibrium sorption capacity data conformed to Langmuir isotherm. The pore diffusion and mass transfer coefficients of As(III) species were significant and contributive to the sorption rate. All these studies and characterisation of free and As(III)–loaded CFC materials by SEM, FTIR and XRD methods led to the suggestion of a plausible mechanism involving complex formation between the two components. The As(III)-CFC sorption system was further investigated by dynamic column study invoking Thomas model. Finally, the desorption studies revealed that the adsorbent CFC could be effectively regenerated by 0.1 M hydrochloric acid, making it a viable and reusable system for As(III) removal.

Keywords: Sorptive removal; arsenic(III), biosorbent, cupressus female cone

Use of bromophenol blue in the spectrophotometric

and turbidimetric determination of

mebrophenhydramine in tablets

Simple, sensitive, rapid and cost-effective methods are described for the determination of mebrophenhydramine hydrochloride (MPH) in pure form and in tablets using Bromophenol Blue (BPB) as a reagent. The spectrophotometric method is based on the formation of an ion-association complex of the drug with BPB in phthalate buffer of pH 3.0, its extraction into chloroform and absorbance measurement at 420 nm. In turbidimetry BPB was used to produce stable turbidity arising from the formation of drug-dye complex of very low solubility at an altered pH condition and reagent-concentration and in the presence of potassium chloride. The absorbance of the turbid suspension was measured at 650 nm. Various parameters affecting the analytical procedures were investigated and optimised. In spectrophotometry, Beer's law is obeyed over the concentration range of 2-12 mg mL^-1 with an apparent molar absorptivity of 1.98´10⁴ L moL^-1 cm^-1 and Sandell sensitivity of 19.39 ng cm^-2. Turbidimetry is applicable in the concentration range of 10-70 mg mL^-1. The limits of detection are 0.10 and 0.44 mg mL^-1 for spectrophotometry and turbidimetry, respectively. The methods were used to determine MPH in standard solution with a coefficient of variation of less than 2%, and were further applied to the determination of MPH in tablets. The results obtained by the proposed methods agree with the label claim. The reliability of the methods was further established by recovery studies applying standard-addition technique.

Keywords: Mebrophenhydramine determination, spectrophotometric, turbidimetric

Studies on the chemistry of thermal drying of

lignite in inert atmosphere

Drying of lignite and its storage for sufficient length of time in dried conditions has been an integral part of industrial economy, yet a fundamental understanding of the physico-chemical changes involved still lags far behind the practical use. Moisture is generally held in lignite by surface forces and oxygenated groups. Elimination of carboxyl groups by thermal decarboxylation has been found to reduce moisture holding capacity of lignite. In this paper a relationship has been shown to exist between carboxyl-oxygen and moisture of lignite at 60 percent relative humidity (RH) condition. Thermal behaviour of carboxylic acid functionality has been studied. Dehydroxylation was not observed at optimum temperature of decarboxylation. The nature and disposition of carboxylic acid functionality in lignite has been indicated.

Molybdenum complexes as precursors of tribologically active substances under extreme pressure conditions

Some molybdenum complexes of N-isonicotinyl-N’ aryl thiosemicarbazides were studied for their tribological activity using four ball test machine. All the compounds were found to be significantly effective extreme pressure lubrication additives. Their EPL efficiency has been compared on the basis of various tribological parameters like wear scar diameter, friction coefficient, initial seizure load (ISL), 2.5s seizure delay load (2.5 s SDL), weld load (WL), mean Hertz load (MHL), pressure wear index (PWI) and flash temperature parameter (FTP). The topography of the wear scar surface of balls in presence of p-chlorophenyl derivative has been studied by scanning electron microscopy at 2.5s seizure delay load and just before weld load. Auger electron spectroscopy has been used to analyze the wear scar surface at just before weld load.

Keywords: Molybdenum complexes, aryl thiosemicarbazides, tribological activity, lubrication additives

Determination of alcohol in petrol-alcohol mixtures

A simple and rapid method for the determination of alcohol in petrol-alcohol mixtures using density measurements is described. The method can determine a minimum of 1% of alcohol by volume. The precision of the method is ± 3%. The method is more useful for field test in the quality assessment of alcohol blended petrol.

Keywords: Petrol-alcohol mixture, alcohol determination, density measurement

Preparation and characterization of molybdenum hydrotreating catalyst
supported on MgO/Al₂O₃ mixed oxide

A series of molybdenum catalysts supported on MgO/Al₂O₃(1:1) mixed oxide were prepared and characterized by BET surface area, X-ray diffraction, temperature programmed reduction and oxygen chemisorption. The catalytic activities for hydrodesulpurization(HDS), hydrogenation(HYD) and hydrocracking(HYC) were determined using thiophene, cyclohexene and cumene as model compounds respectively. Results indicate that at 2- 8% Mo loading, the catalyst is more dispersed and crystallite growth occurred beyond this range. The optimum metal loading for maximum oxygen uptake and catalytic activities for HDS, HYD and HYC was concluded to be 8%. The order of catalytic activity for HDS, HYD and HYC was: HYD>HYC>HDS. However, the Co promoted catalyst showed remarkable increase in both the HDS and HYD activity with no significant change in HYC activity, with the following order: HDS>HYD>HYC, the optimun Co loading being 3%.

Keywords: Hydrotreating, Mo catalyst, hydrosulpurization, hydrogenation, hydrocracking, Co catalyst

Inhibition of mild steel corrosion in formic and

acetic acid solutions

Four organic inhibitors namely, 4-amino-3-methyl-5-mercapto-1,2,4-triazole (AMMT), 4-amino-3-ethyl-5-mercapto-1,2,4-triazole (AEMT), 4-amino-3-propyl-5-mercapto-1,2,4-triazole (APMT) and 4-amino-3-butyl-5-mercapto-1,2,4-triazole (ABMT) were synthesized to investigate their inhibiting actions on corrosion of mild steel (MS) in aqueous solutions containing 20% formic acid and 20% acetic acid by weight loss and potentiodynamic polarization methods. All of these compounds have shown good inhibition efficiency (IE) in the formic acid and acetic acid solutions. IE of these compounds has been found to vary with the concentration of the compounds, temperature, immersion time and concentration of acid solutions. The adsorption of these compounds on the mild steel surface from both the acids has been found to obey Langmuir adsorption isotherm. The values of activation energy (E_a) and free energy of adsorption (DG_ads) indicated physical adsorption of these compounds on the steel surface. The potentiodynamic polarization experiments revealed that all the compounds are mixed type inhibitors.

Keywords: Corrosion inhibitor, mild steel, triazoles, acetic acid, formic acid.

Alkylation of benzene with ethanol over ZSM-5 catalyst with different SiO₂/Al₂O₃ ratios

Alkylation of benzene with ethanol has been done in a laboratory scale reactor with ZSM-5 diluted with silica as a catalyst. The experiments have been done at the different reaction temperatures using different catalysts in the reactor to study the change of activity and selectivity of the desired product. The feed and products were analysed by gas chromatography. Alkylation of benzene with ethanol yielded ethylbenzene as the primary product and small amount of diethylbenzene isomers. For unmodified H-type of ZSM-5 catalyst, higher conversion of benzene and the selectivity for ethylbenzene go through a maximum between 400 and 450 ºC with a SiO₂/Al₂O₃ ratio of around 100. The SiO₂/Al₂O₃ ratios were varied between 34 and 331. Modified B- and Mg- types of ZSM-5 zeolites are also examined.

Keywords: Alkylation, benzene, ZSM-5, selectivity, SiO₂/Al₂O₃ ratios, ethylbenzene

Corrosion inhibition by caffeine – Mn²⁺ system

The inhibition efficiency of caffeine in controlling corrosion of carbon steel immersed in 60 ppm of Cl^- ion environment has been evaluated, in the absence and presence of Mn²⁺ ions, by weight loss method. Influence of sodium dodecyl sulphate, pH and immersion period on the inhibition efficiency of the caffeine-Mn²⁺ ion system has also been investigated. The protective film formed on the metal surface has been analysed by FTIR spectra. The protective film consists of Fe²⁺ - caffeine complex and Mn(OH)₂.

Keywords: Corrosion inhibition, caffeine-Mn²⁺system, carbon steel, chloride ion environment, sodium dodecyl sulphate

Alkylation of naphthalene with t-butanol over

zeolite Y: Influence of reaction environment and reaction kinetics

The t-butylation of naphthalene with t-butanol over different Y-zeolites and at different environments is reported. The zeolites investigated are H-Y, RE-Y and three US-Y samples with different Si/Al ratios. Though, as expected, increasing the reaction temperature (160-180 ºC) increases naphthalene conversion, increasing the TBA/naphthalene mole ratio beyond 2 results in a decrease in conversion, presumably due to poisoning by the larger amount of water produced during dehydration. Both activity and yield of dialkylnaphthalenes increase on RE exchange and dealumination of H-Y. Higher conversions are obtained when the reaction is conducted under neat conditions than in the presence of the solvent cyclohexane or the added gas, N₂.

Studies of printing inks on starch blended and surface grafted polyethylene film for flexible packaging

Grafted vinyl acetate surface of starch blended biodegradable polyethylene film was printed with industry standard printing inks based on polyamide resin and organic solvents. Various print and packaging properties were studied to find suitability of the use of such grafted polyethylene film in comparison to ungrafted starch blended polyethylene film and industry standard corona treated polyethylene film. The use of such grafted film was also comparatively studied in polyethylene laminate packaging. Prints and laminates using industrial standard grade polyethylene, starch blended biodegradable polyethylene and grafted starch blended polyethylene film, were put on soil burial test and studied for biodegradable properties.

Keywords: Printing ink, grafted polyethylene film, flexible packaging, biodegradable

A population balance model for miniemulsion polymerization

Miniemulsion polymerization is mechanistically distinct from the conventional emulsion polymerization in several aspects; the most important being that the nucleation occurs in the small and stable monomer droplets. This process is being used to produce polymer latexes of unusual characteristics. The initial droplet size distribution and the final particle size distribution in miniemulsion polymerization are broad. This has not been addressed by the present models, which are based on the grosser perspectives of this system and assume monodisperse droplet size and particle size distributions. A population balance model for the miniemulsion polymerization that incorporates the particle size distribution is developed in this work. The model predictions are verified against data taken from the literature.

Influence of microwave irradiation on enzymatic activity of invertase in aqueous and organic solvents

Sucrose hydrolysis reaction, catalysed by invertase under microwave irradiation was carried out in aqueous, isopropanol + water and polyethylene glycol + water system. The effect of conventional and microwave heating on the rate of hydrolysis was studied under a range of physical exposure conditions. The catalytic activity of invertase in aqueous and organic solvents were measured at different temperatures. Enhanced reaction rate and yield in organic media was observed over aqueous media using microwave heating.

Effect of flotation reagents on the wet grinding of celestite concantrate

In this study, the grinding of celestite concentrate in presence of grinding aids, used for celestite ore, flotation has been investigated in a laboratory wet-ball mill as a function of time and concentration of grinding aids. In the experiments, Aero-801, sodium oleate and sodium silicate have been used as grinding aids at the concentrations of 10, 100 and 1000 g/t.

While sodium oleate and sodium silicate have beneficial effect in longer grinding times at concentrations of 100 and 1000 g/t, they have adverse effect on grinding at all grinding times at concentration of 10 g/t as evident from particle size. d₈₀ values of ground products are coarser than that without grinding aid. Aero-801 is the best among the grinding aids tested for the concentrations studied. Considering the fineness of the ground products desired, 100 g/t concentration of Aero-801 appears to be proper for grinding of celestite concentrate.

Keywords: Flotation, celestite, aero-801, sodium silicate, sodium oleate, grinding aid

Effect of magnetic field on membrane potential

Transport has been studied from the point of view of irreversible thermodynamics for aqueous solutions of sodium chloride, potassium chloride and lithium chloride across a sintered disc impregnated with cellulose acetate under the influence of variable magnetic field. Teorell-Meyers-Siever theory has been used to evaluate the ionic transport numbers. The data has been interpreted for Permselectivity and Fixed Charge Density in all the electrolytes and comparisons have been discussed.

Keywords: Ionic transport, fixed charge density, NaCl, KCl, LiCl, permselectivity, magnetic field, membrane potential

Liquid drainage in static foam: Analogy with liquid drainage through packed bed

High intensity ultrasonic vibrations are known to be efficient at destabilizing stationary foams. In this paper, the effect of the application of ultrasonic vibrations generated by an ultrasonic bath has been studied on the drainage of static foam. The vibrations are found to enhance the drainage rate of the foam and the model could be extended to correlate these drainage rates. This model can also be used to predict the variation in the foam cell size and shape factor during drainage. The effect of type of sparger and column diameter on the drainage rate has been studied. The rate of foam collapse depends on the foam cell size, which in turn depends on the sparger used for foam generation. The foam drainage and collapse rates were found to increase with the decrease in the column diameter.

Vapour phase transesterification over solid acids for the synthesis of isoamyl salicylate

The transesterification of methyl salicylate with isoamyl alcohol has been studied in vapour phase over solid acid catalysts for the synthesis of isoamyl salicylate. The catalysts used include simple oxides ¾ Al₂O₃, SiO₂, ZrO₂ and mixed oxides ZrO₂-Al₂O₃ and ZrO₂-SiO₂. The effect of sulphation on the catalytic activity of the oxides and mixed oxides has also been investigated for this reaction. Catalytic activity studies have been conducted at 200^oC for two different flow rates, 5 and 10 mL/h to check the effect of the contact time of the reactants with the catalyst. All the catalysts used in the reaction have been found to be active for the formation of isoamyl salicylate via transesterification of methyl salicylate with isoamyl alcohol. SO₄²/ZrO₂-SiO₂ (2:8) has been found to be the most active catalyst with 63% conversion of methyl salicylate to isoamyl salicylate. SO₄^2-/ZrO₂, which exhibited good selectivity was chosen as the catalyst for optimisation of the reaction conditions to obtain better yield and higher selectivity of isoamyl salicylate. Optimum yield of isoamyl salicylate was obtained with the following reaction conditions: amount of catalyst = 0.5 g, calcination temperature = 550^oC, reaction temperature = 200 ^oC, preheater temperature = 250 ^oC, molar ratio of methyl salicylate to isoamyl alcohol = 1:1.

Keywords: Transesterification, solid acid catalysts, methyl salicylate, isoamyl alcohol

Low temperature oxidation of ethanol

Oxidation characteristics of ethanol in the temperature range 200 to 1000 ^oC suitable to its use in automobiles are studied to highlight the role and optimum values of different combustion controlling parameters for its clean combustion. Sensitivity evaluation of different reaction paths has concluded some important reactions responsible for the ethanol oxidation. It is observed that clean combustion of ethanol can be obtained with a proper combination of combustion parameters viz., temperature, C₂H₅OH/O₂ mole ratio and residence time.

Photocatalytic bleaching of amaranth dye

over ZnO powder

The photocatalytic bleaching of amaranth over zinc oxide powder was observed spectrophotometrically. The effects of the concentration of amaranth, pH, amount of semiconductor, light intensity on the rate of the photocatalytic bleaching were also studied. A tentative mechanism for the photocatalytic bleaching of amaranth is proposed.

CO oxidation over Pd/g-FeMnO₃ catalyst

g-FeMnO₃ samples with and without Pd metal impregnation have been prepared by co-precipitation method and investigated by powder X-ray diffraction and ⁵⁷Fe Mossbauer spectroscopy techniques, for its bulk characteristics. Catalytic activity of these samples has been studied for CO oxidation reaction by injecting CO or (CO+O₂) pulses over their surface, with a view to delineate the role of Pd metal and reducible cations during this reaction. Pd metal impregnation over the surface of g-FeMnO₃, leads to significant improvement in its catalytic activity, particularly at lower temperatures. Based on these experiments, clear evidence for the low temperature (T~350 K) disproportionation of CO over the surface of Pd metal particles and lattice oxygen incorporation during CO oxidation reaction, have been presented. From the comparative study of Fe₂O₃, Mn₂O₃ and FeMnO₃, the existence of any synergistic effects between Fe³⁺ and Mn³⁺ cations, is ruled out for FeMnO₃, mixed oxide system.

The nature and composition of water

The nature and composition of water has intrigued scientists since the beginning of philosophical and scientific inquiries. From being a religious symbol and one of the primeval elements it had to wait until the end of the eighteenth century to elucidate that water was a compound material.

ISSN:0971-457X		CODEN:ICHTEU 11(3) 293-450
VOLUME 11	NUMBER 3	MAY 2004