Indian Journal of Chemical Technology
Volume 9 Number 4 July 2002
CODEN:ICHTEU 9(4) 279-376 ISSN: 0971-457X
CONTENTS
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Research Articles |
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Iron oxide coated sand
as an adsorbent for separation and removal of phenols |
285 |
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Influence of carbon-oxygen surface groups
on the adsorption of phenol by activated carbons |
290 |
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A comparative kinetic and mechanistic
study of saponification of industrially important esters viz., mono and distearates,
oleostearates of glycol, glycerol and methyl salicylate in alcohol-water,
dioxane-water, DMSO-water and DMF-water moieties |
297 |
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Vermicomposting of paper waste with the anecic
earthworm Lampito mauritii Kinberg |
306 |
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Studies on the miscibility of hydroxy
propyl methyl cellulose and poly(vinyl pyrollidone) blends |
312 |
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Amarakala C Hiremath, B S
Sherigara, K Prashantha, K Sheshappa Rai & S Prassanna Kumar |
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Morphology of PS/PMMA blends and their
solution rheology |
316 |
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Optimization of different experimental
parameters for the determination of heat capacity of thoria using
differential scanning Calorimetry (DSC) |
324 |
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Catalytic activity of DBTDL in
polyurethane formation |
330 |
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Kinetics of toluene methylation over
silica modified HZSM-5 zeolites |
334 |
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Ultrasonic and
viscometric behaviour of hexadecane-butanol mixtures at different
temperatures |
341 |
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Modelling and simulation of extraction
behaviour of n-butyraldehyde in 30%
TBP/n-dodecane purex biphasic
system |
346 |
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Contd. |
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Anodic dissolution and passivation of
binary alloys¾An
overview |
350 |
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Study of analgesic activity of some novel
1-(9¢-acridinyl)-5-substituted phenyltetrazoles |
361 |
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Educator
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The history of fluorine from discovery to
commodity |
363 |
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Chem-Tech Scan
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373 |
Indian Journal
of Chemical Technology
Vol. 9, July 2002, pp. 285-289
Iron oxide coated sand as an adsorbent
for separation and removal of phenols
D K Singh*, Bhavana Srivastava & Pushpa Yadav
Iron oxides were coated onto the surface of sand, and this composite media was used for adsorption studies of phenolic compounds. These form complexes on the surface of hydrous iron oxide. Probably, the coordination of ligands with the central metal ion occurs through the phenolic oxygen. Adsorption capacities, rate of adsorption and breakthrough curves were studied. The adsorption of phenols remains same in the pH range 3-6. Distribution coefficients (Kd ) of 17 phenols were determined in water and sodium hydroxide solutions (0.1-0.5 M). On the basis of difference in Kd values some quantitative separation of phenols were achieved. The adsorbed phenols were desorbed quantitatively with 1 M NaOH and the same column could be used for 4-5 cycles consecutively. A small phenol removal unit was also studied for phenol removal from water.
Indian Journal
of Chemical Technology
Vol. 9, July 2002, pp. 290-296
Influence of carbon-oxygen surface
groups on the adsorption of phenol by activated carbons
R C Bansal*', Diksha Aggarwal, Meenakshi Goyal & B C Kaistha
Adsorption isotherms of phenol from its aqueous
solutions on four samples of activated carbons having different surface areas
and associated with varying amounts of carbon-oxygen surface groups have been
determined in the concentration range 20-1000 mg/L. The adsorption of phenol
does not depend upon surface area alone but is also influenced by the presence
of carbon-oxygen surface groups. The amount of these surface groups was
enhanced by oxidation with nitric acid, ammonium persulphate and hydrogen
peroxide and was decreased by degassing the activated carbons at gradually
increasing temperatures of 400, 650o and 950oC. The oxidation of the carbons
decreases the adsorption of phenol, the extent of decrease depending upon the
nature of the oxidative treatment. The adsorption increases on degassing of the
carbon samples, the increase depending upon the nature of the carbon-oxygen
surface groups being eliminated at that temperature on degassing. The results
indicate that while the presence of acidic carbon-oxygen surface groups which
are evolved as CO2 suppresses the adsorption of phenol, the presence of
non-acidic surface groups which are evolved as CO tends to enhance the
adsorption of phenol.
Indian Journal
of Chemical Technology
Vol. 9, July 2002, pp. 297-305
A comparative
kinetic and mechanistic study of saponification of industrially
important esters viz., mono and
distearates, oleostearates of glycol,
glycerol and methyl salicylate in
alcohol-water, dioxane-water,
DMSO-water and DMF-water moieties
B Madhava Rao* & K Gajanan
Kinetic and mechanistic studies of saponification of
the above structurally related and industrially important mono and diesters and
their comparative behaviour of saponification process have been investigated.
Time ratio method and Swain's standard data for series first order reactions
have been utilized for the evaluation of rate data and thermodynamic parameters
viz. DE¹, -DH¹, DG¹, DS¹ and log A for mono and
diesters which involve the competitive and consecutive saponification
reactions. These investigations also indicate that mono esters undergo saponification
process much faster than diesters and furthermore the oleostearates are more
saponifiable than stearates. In general, these processes are much faster in
dioxane-water, DMSO-water and DMF-water systems than in alcohol-water system.
Further, the dAB (inter-ionic distance in the double sphere model of an
activated complex) of mono esters are much smaller than diesters confirming
that saponification processes are relatively faster in mono esters than
diesters.
Indian Journal
of Chemical Technology
Vol. 9, July 2002, pp. 306-311
Vermicomposting of paper waste with
the anecic earthworm
Lampito
mauritii Kinberg
S Gajalakshmi, E V Ramasamy & S A Abbasi*
Long term performance of ‘vermireactors’ in which paper waste was
converted to vermicasts by the anecic earthworm Lampito mauritii Kinberg has been assessed. The study
is focussed on four aspects: (a) recovery of vermicasts in digesters fed with
paper blended with cowdung in 4:1, 5:1, and 6:1 ratios (by weight), (b)
reproduction/mortality of earthworms in the reactors, (c) growth of earthworms
in terms of increase in zoomass, and (d) the effect of digester volume on the
three aforementioned factors. These studies are a sequel to the work reported
earlier2 where four species of epigeic and anecic earthworms were screened for
their efficiency and sustainability in processing waste paper. The
studies had indicated L. mauritii and Eudrilus eugeniae Kinberg to be the most
efficient producers of vermicasts, with L. mauritii a shade above E. eugeniae.
As L. mauritii is an indigenous species whereas E.eugeniae is an exotic in the
Indian context, it seems that the former may adapt better ecologically, hence
is more resilient, than the latter.
Indian Journal
of Chemical Technology
Vol. 9, July 2002, pp. 312-315
Studies on the miscibility of
hydroxy propyl methyl cellulose and
poly(vinyl pyrollidone) blends
Amarakala C Hirematha, B S Sherigara*a, K
Prashanthaa, K Sheshappa Raib & S Prassanna Kumarc
Compatibility of polyvinyl pyrollidone (PVP) and hydroxypropyl methyl cellulose (HPMC) has been investigated by solution viscometric, ultrasonic, differential scanning calorimetric (DSC) methods and fourier transform infrared spectroscopic (FTIR) techniques. Ultrasonic velocity and adiabatic compressibility versus blend composition are plotted and found to be linear. The results obtained reveal that HPMC and PVP form a miscible blends in the entire composition range. FTIR spectroscopy demonstrated that there is strong intermolecular hydrogen bonding between carbonyl group of PVP and free hydroxyl group of HPMC.
Indian Journal
of Chemical Technology
Vol. 9, July 2002, pp. 316-323
Morphology of PS/PMMA blends and
their solution rheology
S R Vashishtha, Navin Chand & S A R Hashmi*
Polystyrene (PS)/Polymethylmethacrylate (PMMA) blends were prepared by using solution casting method. These polymers show a tendency of mixing each other in compositions where PS is 60 wt.% or above. PS and PMMA mixed partially and formed PS-rich-phase and PMMA-rich-phase in the blend. Morphology of PS/PMMA blend prepared by solution method is discussed with the help of fractured micrographs obtained by Scanning Electron Microscope. Flow curves of solutions of PS and PMMA and their blends in toluene were studied at room temperature. The effects of blend concentration and composition on shear stress and shear viscosity were studied. The viscosity data was obtained for various weight percent of PMMA and PS separately. 15 and 20 wt% solutions of PS/PMMA blends were also studied. Power law model was fitted for shear dependency of viscosity of solutions. Shear stress increases with the addition of PS in PS/PMMA blend solution. Increase in concentration of PMMA decreased the viscosity of the PS/PMMA solution. All these systems behave as pseudoplastic systems.
Indian Journal
of Chemical Technology
Vol. 9, July 2002, pp. 324-329
Optimization of different
experimental parameters for the determination of heat capacity of thoria using
Differential Scanning Calorimetry (DSC)
M K Saxena, S B Deb, K L Ramakumar & V Venugopal
For investigating the physico-chemical properties of thorium and its compounds, differential scanning calorimetry (DSC) has been employed for measuring the molar heat capacity (Cp) of ThO2 in the temperature range 373-773K. Even though Cp values of thoria are available in the literature, DSC has been used for the first time in the present work as it is sensitive, fast, simple and requires small sample size. The DSC curve obtained was desmeared to obtain the true heat flow rate, which was then used to compute the Cp values. A number of sample-dependent and the operator-dependent parameters were optimized to obtain the results within the best possible precision and accuracy. With proper control of different influencing parameters it was possible to obtain the results within an accuracy and precision of 10%.
Indian Journal
of Chemical Technology
Vol. 9, July 2002, pp. 330-333
Catalytic
activity of dbtdl in polyurethane
formation
Sobhan Niyogi, Sanjay Sarkar & Basudam Adhikari*
Polyurethane has been prepared from neopentyl glycol (NPG) and toluene diisocyanate (TDI) using dibutyltin dilaurate (DBTDL) catalyst. The rates of both the uncatalyzed and catalyzed polyurethane formation reactions were investigated. In case of catalyzed reaction the sequence of addition of catalyst was also investigated and it was observed that the activity of the catalyst is dependent on the sequence of addition of DBTDL catalyst. Titrimetric method was used for the determination of residual isocyanate content. Highest reaction rate was observed when the catalyst was added after the addition of TDI to diol and lowest rate was observed when no catalyst was used. It was observed that when the catalyst was added to NPG followed by TDI addition the rate of reaction was slower compared to that when catalyst was added to the mixture of diol and TDI. 1H NMR and IR study of the complex formation between the tin catalyst and diol was evaluated to account for the lower reaction rate.
Indian Journal of
Chemical Technology
Vol. 9, July 2002, pp. 334-340
Kinetics of toluene methylation over
silica modified HZSM-5 zeolites
J Dasa, P R Chara, A B Halgeria*,
R K Mewadab & N Subrahmanyamb
Kinetics of
toluene alkylation with methanol over silica modified HZSM-5 catalyst under
experimental conditions that are close to envisaged industrial conditions are
studied. Of the several possible kinetic models tested and compared, a simple
power law model is found satisfactory in predicting toluene conversions and p-xylene selectivities. However, further
studies with a comprehensive experimental program, is suggested for
investigating the numerous side reactions and to account for a large number of
by-products observed.
Indian
Journal of Chemical Technology
Vol. 9, July 2002, pp. 341-345
Ultrasonic and viscometric behaviour
of hexadecane—butanol mixtures
at different temperatures
Rita Mehra* & Rekha Israni
Ultrasonic speed, density and viscosity data were measured for binary mixtures of hexadecane and butanol over the entire range of composition and at different temperatures ranging between 298.15 and 318.15 K at 5 K interval. From the experimental data, the values of adiabatic compressibility (KS), excess adiabatic compressibility (KSE), acoustic impendence (Z), excess viscosity, excess free energy of activation of flow (G*E) were calculated. The results are interpreted in terms of degree of interaction between component molecules. The data at various temperatures also provide an opportunity to study the effect of temperature on the sign and magnitude of the deviation in compressibility.
Indian Journal
of Chemical Technology
Vol. 9, July 2002, pp. 346-349
Modelling and simulation of
extraction behaviour of n-butyraldehyde
in
30%TBP/n-dodecane purex biphasic system
Shekhar Kumar* & S B Koganti
Use of butyraldehyde for selective reduction of Neptunium has been reported earlier. As there is no model available to account for its extraction behaviour in the conventional purex system, the reported experimental results could be explained only on the qualitative basis. The reported data were analyzed to determine its solvation number and an empirical model was developed for estimation of its distribution coefficients under purex conditions. The reported counter-current extraction run in mixer-settlers was also computer simulated using an in-house developed purex code SIMPSEX. The simulated profiles were compared with the experimental stage profiles and a satisfactory agreement was observed.
Indian Journal
of Chemical Technology
Vol. 9, July 2002, pp. 350-360
Anodic dissolution and passivation
of binary alloys—An overview
J Mathiyarasu,
N Palaniswamy & V S Muralidharan*
The dissolution of a metal occurs with the transfer
of one or more electrons. The dissolution depends on potential, which may or
may not result in passivation. In the case of dissolution of binary alloys, the
dissolution may be selective for the less noble metal or simultaneous
dissolution may occur. The passivation and depassivation processes on the alloy
surface depend on the electrode potential and anions present in the medium. The
depassivation may be uniform or with film breakdown at selected sites.
Indian
Journal of Chemical Technology
Vol. 9, July 2002, pp. 361-362
Study of analgesic activity of some
novel 1-(9’-Acridinyl)-5-substituted phenyltetrazoles
Helen P Kavithaa* & N Balasubramanianb
Tetrazole and acridine derivatives are well known biologically active compounds by themselves. This paper deals with the analgesic activity of some novel tetrazole derivatives containing acridine ring. The results of the study indicate that the newly synthesized tetrazole derivatives show fairly good analgesic activity.
Indian Journal
of Chemical Technology
Vol. 9, July 2002, pp. 363-372
The History of Fluorine—From
discovery to commodity
Jaime Wisniak*
Fluorine was the last of the halogens to be isolated. The extreme difficulties and dangers of handling it retarded substantial commercial applications until World War II when it became essential for the development of nuclear devices. Development of industrial processes for the manufacture of hydrogen fluoride and chlorofluorinated hydrocarbons turned fluorine and its derivatives into a major chemical commodity. The end use pattern of fluorine has reflected the changes in social appreciation of environmental protection and safety.