bluuebunny/crossref_metadata_2025 huggingface dataset:
Catalytic dehydrogenation of propane on chromia, palladium and platinum supported catalysts
Authors: Ashmawy Fathy M.
Published: July 2010

The dehydrogenation of propane to propylene over Cr2O3/Al2O3, Pd/Al2O3 and Pt/SiO2 has been investigated in the temperature range 580–618°C. Runs were performed on propane, alone or in the presence of nitrogen (as a diluent), with complete analysis of the reaction products. The reaction was carried out in a fixed bed reactor at space velocities from 450–800 h−1 which are close to industrial values and at pressures from 0.3 to 1 atm. A set of runs was made over a commercial chromia‐alumina catalyst (10% Cr2O3) and over a promoted catalyst prepared in the laboratory by impregnation (16.8% Cr2O3 + 2% K2O). The latter catalyst showed high selectivity and stability even when subjected to continuous cycles of dehydrogenation, regeneration and purging. Of the two noble metal supported catalysts used, reduced Pd/Al2O3 showed higher activity than Pt/SiO2 at 618°C. The former catalyst gave a propylene yield of around 98% at 20% conversion level.
Solid‐phase acylating agents. I. The preparation and reactions of acetylpolystyrenesulphonates in aqueous solution
Authors: Laird Robert M. , Spence Michael J.
Published: July 2010

Methods of preparing acetylsulphonate acylating reagents from commercial sulphonic acid ion‐exchange resins and their reaction with aqueous aniline solutions are described. The relative merits and limitations of the techniques employed are discussed.
Metachromic interactions between azo and triphenylmethane dyes in aqueous solution. II. The effect of organic solvents on the interaction
Authors: Owen Eryl D. , Al‐Akil Tarek N.
Published: July 2010

The interaction between dilute aqueous solutions of the disazo dye Brilliant Orange and the triphenylmethane dye Crystal Violet results in a decrease in the absorption of Crystal Violet in the region 550–600 nm and the appearance of a new absorption at 494 nm. The decrease in absorbance at 590 nm is characteristic of the metachromic interactions of Crystal Violet with a wide variety of polyanion substrates while the increase at 494 nm is due to the conversion of Brilliant Orange from its azo to its hydrazone tautomer. The relative effects of a variety of organic solvents in reversing the interaction has been investigated.
Continuous dissolution of sodium and potassium silicate glass in a tower dissolver
Authors: Jorgensen Frank R.
Published: July 2010

Sodium and potassium silicate glass was continuously dissolved in a tower dissolver operated at atmospheric pressure. In pilot experiments the rate, controlled by the dissolution process occurring at the glass/liquor interface, was dependent on surface area, temperature, type, and chemical composition of the glass, but was independent of concentration and flowrate. Activation energies for the dissolution process lay in the range 22‐48 kJ/mol, while typical rates of dissolution were 26 and 21 kg m−3 h−1 for 2.0 and 3.2 SiO2/Na2O weight ratio sodium silicate glass at 99°C. The corresponding rate for potassium silicate glass of SiO2/K2O weight ratio 2.0was 195 kgm−3h−1 at 80°C. Loss of potassium silicate due to the formation of insoluble compounds was prevented by operating below 93°C. Tower dissolvers warrant further consideration as an alternative to conventional digestors, having the advantages of continuous operation and uniform product density.
A phase model for the gas–liquid equilibria in the ammonia–carbon dioxide–water–urea system in chemical equilibrium at urea synthesis conditions. I. Theory
Authors: Lemkowitz Saul M. , Diepen George A. M. , van den Berg Pieter J.
Published: July 2010

A ternary phase model of the reciprocal salt‐pair type (square composition plane) is presented to describe the gas–liquid equilibria of the ammonia–carbon dioxide–water–urea system in chemical equilibrium at urea synthesis conditions. The components of the model are CO2, H2O and (2NH3). Urea is represented by the equation:.

magnified image and is therefore located at the corner of the composition square diagonally opposed to water. Characteristic of this phase model (at constant temperature) is the occurrence of minimum bubble‐ and dew‐points in planes located parallel to the (2NH3)‐CO2 diagonal. The point of tangency of the bubble‐ and dew‐point lines formed by these points forms the ternary azeotropic point. Intercepting the azeotropic point is a plane parallel to the urea–water diagonal; at the azeotropic point the bubble‐point line in this plane reaches a maximum pressure value. The ternary azeotrope is of the saddle type.
Preparation of mono(dimethylglyoxime)(triphenylphosphine)‐halogenocobalt(I) complexes and their application as homogeneous catalysts in reduction of aromatic nitrocompounds
Authors: Datta Manik C. , Saha Chitta R. , Sen Debabrata
Published: July 2010

The complexes [Co(I)(DMGH)(PPh3)X].C2H5OH (XCl/Br) have been prepared and characterised by elemental analysis, infrared and electronic spectral studies and magnetic measurements. These compounds have been used as homogeneous catalysts for the reduction of nitrobenzene at atmospheric and higher pressures. From a study of various operational parameters, it has been observed that the reduction at atmospheric pressure was only possible in a basic ethanolic medium and resulted in 64% of azobenzene on input nitrobenzene basis whereas at higher pressure (4.2 × 103 kN/m2), 60% of aniline on the same basis could be obtained in neutral ethanolic medium. The optimum conditions were established both under normal pressure and under high pressure.
The solvation of cellulose by the action of nitrogen tetroxide in organic solvents
Authors: Abou‐State M. Amine , Awad Boshra M.
Published: July 2010

This article reviews the solvation of cellulose by the action of N2O4 in presence of a suitable proton acceptor and its subsequent regeneration. The mechanism of the nitrosation reaction and the factors affecting cellulose degradation during solvation and regeneration are discussed. The possible industrial applications of this process as well as the use of cellulose nitrite in the preparation of novel cellulose derivatives are also included.
Oxidation of ferrous hydroxide suspension. III
Authors: Prasad Turaga P. , Ramasastry Vemuri V.
Published: July 2010

The rate equation developed in our earlier studies has been analysed and discussed. It has been found that the rate of oxidation of ferrous hydroxide suspensions obtained by the addition of calcium hydroxide, sodium and calcium carbonates, ammonium and sodium hydroxides follows zero order kinetics.
Preparation of pyridinemonocarboxylic acids by catalytic vapour phase oxidation of alkylpyridines. I. Oxidation of 2‐ and 3‐picoline and decarboxylation of 2‐ and 3‐pyridinecarboxylic acid in the vapour phase
Authors: Järås Sven , Lundin Sten T.
Published: July 2010

The vapour phase oxidation of 2‐picoline with air using a singly promoted vanadium catalyst (V2O5/SnO2, mole ratio 1/1.5), at a temperature of 375°C and a space velocity of 6130 h−1, gave a 69% conversion with a selectivity of 64% for 2‐pyridinealdehyde. No pyridoin formation was detected. In the vapour phase oxidation of 3‐picoline using a doubly promoted vanadium catalyst (V2O5‐TiO2‐Na2O with V/Ti/Na=100/20/1.15) at a temperature of 400°C and a space velocity of 1450 h−1, a 94% conversion of 3‐picoline was obtained with a selectivity of 51% for niacin (3‐pyridinecarboxylic acid) and 1% for 3‐pyridinealdehyde. By varying the atom ratio V/Ti, the catalyst V/Ti = 100/25 was found to be the most active one. The decarboxylation of 2‐ and 3‐pyridinecarboxylic acid in the vapour phase was also investigated under the conditions used in the oxidation of the picolines to the acids. At 350°C about 90% decarboxylation of picolinic acid occurs under these conditions, while only a few per cent of the niacin decarboxylated to pyridine between 300 and 500°C.
Mechanism of the liquid‐phase oxidation of cumene, cyclohexene and tetralin catalysed by MnO2
Authors: Krishna Lanka V. G. , Srivastava Rameshwar D. , Rao Musti Someswara
Published: July 2010

Oxygen absorption by solutions of cumene, cyclohexene and tetralin in monochloro‐benzene has been measured at 80, 60 and 65°C with MnO2 catalyst in the inhibition region, and shows second order rate dependence with respect to hydrocarbon concentration. The limiting rate of oxidation is satisfactorily described by a 3‐parameter equation based on the reaction mechanism proposed by Neuburg et al. Statistical estimates of the parameters for cumene are given from this work and for cyclohexene and tetralin from work presented elsewhere.
A convenient one step synthesis of 2,4‐dialkyl‐2‐hydroxy‐alkyl‐γ‐butyrolactone using lithium naphthalenide
Authors: Fujita Tsutomu , Watanabe Shoji , Suga Kyoichi , Hokyo Masamoto
Published: July 2010

One mole of propionic acid (I) reacts with 2 mol of 1,2‐butylene oxide (II) in the presence of lithium naphthalenide to give 4‐hydroxy‐2‐(2′‐hydroxybutyl)‐2‐methylhexanoic acid (V), which can be easily converted into 2‐(2′‐hydroxybutyl)‐2‐methyl‐4‐ethyl‐γ‐butyrolactone (VII). Similarly, 2,4‐dialkyl‐ and 2,4,4‐trialkyl‐2‐hydroxyalkyl‐γ‐butyrolactones were prepared from other carboxylic acids having two hydrogens at 2‐position and various epoxides.
Rapid qualitative identification of sulphonamides by mass spectrometry
Authors: Davis Reg. , Hurst Derek T. , Taylor Albert R.
Published: July 2010

Rapid qualitative identification of the sulphonamides present in pharmaceutical preparations is conveniently carried out using mass spectrometry. Direct introduction of a small quantity of the powdered tablet into the mass spectrometer results in the production of characteristic ions even in preparations containing a mixture of therapeutically active constituents and without prior separation of the various constituents.
Effect of cooperativity on microbial growth
Authors: Kargi Fikret
Published: July 2010

The classical Monod equation for the specific growth rate of a microbial population can be derived by assuming a single substrate enzyme‐catalysed reaction (Michaelis‐Menten kinetics) as the rate‐limiting step in microbial growth. In some cases the enzyme which catalyses the rate‐limiting step in microbial growth may have more than one substrate binding site and the binding of one substrate molecule to the enzyme facilitates the binding of the next substrate molecule (cooperativity). The presence of cooperativity changes the form of the Michaelis‐Menten equation for enzyme‐catalysed substrate reactions and also the Monod equation for microbial growth. The number of interacting active sites on an enzyme molecule is an additional parameter in this case. In this article, the cooperative growth model for n interacting sites on the enzyme is derived and compared with the classical Monod model.
Biotechnology. The way ahead
Authors: Humphrey Arthur E.
Published: July 2010

The future for biotechnology looks very bright. Opportunities are increasing, largely because of advances in genetics and in computer‐aided automation. In the past many biotechnology opportunities have arisen out of crisis‐oriented problems. For example, acetone/butanol fermentations were developed to solve a need for acetone to manufacture cordite during World War I and penicillin fermentations evolved because of the need to develop antibiotics to prevent wound infections in World War II. It is felt that future opportunities will emerge largely from similar crises. These probably will involve chemical feedstock supply, alternative forms of energy, applications of genetics, health care and delivery problems, environmental concerns and computeraided automation.
Industrial‐scale operation of microbial processes
Authors: Brown D. E.
Published: July 2010

Interactions between fermentation process development and plant design are explored. An attempt is made to identify the various aspects of microbial reaction and material‐transport control of process rates. In scale‐up some factors remain constant and some can change and the importance of each is discussed. The case for the use of a stirred fermenter in batch processing is developed and the various non‐technical constraints that can determine the scale of operation are described. The production of desirable fluid characteristics at different scales of operation are discussed and it is shown that a deviation from geometrical similarity may be necessary for fermentation process scale‐up. A design procedure for aeration‐limited processes reveals the complex multitude of factors that must be considered in fermentation‐equipment design.
Two‐liquid‐phase biocatalytic reactions
Authors: Lilly M. D.
Published: July 2010

The development of biocatalytic reactors for the conversion of high concentrations of water‐insoluble reactants is at the same stage that systems for water‐soluble reactants had reached almost a decade ago. There are still many problems and much research to be done before we fully understand such systems. Nevertheless, we can confidently expect to see new commercial processes with multiliquid biocatalytic reactors during the next decade.
Immobilised multienzyme systems and organelles
Authors: Legoy M. D. , Gellf G. , Ergan F. , Cocquempot M. F. , Larreta Garde V. , Thomas D.
Published: July 2010

Enzyme technology has demonstrated its economic and industrial potentials by the successful development of the ‘first generation’ of immobilised enzymes which concern simple degradative enzymes which by hydrolysis, oxidation and isomerisation yield products with rather limited added values. A new objective is to prepare industries to develop a ‘second generation’ of enzyme reactors in which sophisticated multienzyme systems will catalyse the synthesis of fine chemicals of high added value. There are two kinds of solutions to develop such new systems: immobilisation of subcellular organelles such as mitochondria, whole bacteria or fragments (chromatophores), chloroplasts (thylakoids). etc.; immobilisation of multienzyme systems including cofactor regeneration and realisation of multienzyme reactors like continuous stirred‐tank reactor. Experimental examples dealing with both topics are described.
Current strategies in the search for bioactive microbial metabolites
Authors: Nisbet Louis J.
Published: July 2010

New microbial metabolite screening currently requires an interdisciplinary team consisting of microbial ecologists, geneticists, molecular biologists, biochemists, microbial physiologists, fermentation technologists and chemists. The increasing difficulty in discovering new compounds of clinical potential can only be overcome by maximising the input of the above disciplines. Possible strategies for constructing a genetically diverse ‘bank’ of microorganisms, including naturally occurring and genetically manipulated strains, are reviewed. Also, the design of environmental conditions optimal for the over‐production of metabolites and the types of screens that are selective for compounds of potential utility are discussed. The value of target‐selective screen techniques is illustrated with experiences gained in the search for new β‐lactams.
Role of plasmids in producers of macrolides
Authors: Schrempf Hildgund
Published: July 2010

Several strains of Streptomycetes producing macrolide antibiotics were found to contain extrachromosomal DNA, but it could be shown that the syntheses of macrolides are not necessarily plasmid‐determined. A plasmid‐bearing strain, Streptomyces reticuli, synthesising melanin and the macrolide leucomycin has been studied together with several variants arising after treatment with intercalating agents. Variants forming no melanin and (or) aerial mycelium possess altered extrachromosomal DNA and those which lack plasmid DNA do not produce aerial mycelium, melanin or the antibiotic on agar plates. In contrast with the wild‐type of S. reticuli, the plasmidless variants contain amplified nucleotide sequences within their chromosomal DNA. The significance of the changes within the chromosomal and extra‐chromosomal DNA in respect to the production of secondary metabolites is discussed.
Immobilised plant cells: General aspects
Authors: Brodelius Peter , Mosbach Klaus
Published: July 2010

The immobilisation of plant cells grown in suspension cultures by entrapment in various gels is described. The viability and biosynthetic capacity of such immobilised cells have been investigated. Model studies covering different aspects of biosynthesis, i.e. biotransformation, synthesis from added precursors and synthesis de novo from a simple carbon source, are described. In some model studies it has been observed that the immobilised cells can produce higher amounts of secondary products than freely suspended cells under the same conditions. Furthermore the permeabilisation of plant cells for continuous release of formed products with subsequent immobilisation is also discussed.
Liposome‐protoplast interactions
Authors: Makins John F. , Holt Geoffrey
Published: July 2010

A large number of different biological compounds can be encapsulated in liposomes and then delivered into the cytoplasm of cells by fusing these lipid vesicles with protoplasts. The essential properties of protoplasts and liposomes are briefly described. Examples of two liposome‐protoplast interactions, involving the delivery of intermediates of antibiotic biosynthesis into fungi and DNA into Streptomyces are discussed. References are made to other experiments suggesting that liposomes may be useful in many areas of biotechnology.
X‐ray powder diffraction studies of basic lead carbonate as a stabiliser in plasticised polyvinyl chloride
Authors: John Michell E. W. , Ng Kok Y.
Published: July 2010

Strips from a polyvinyl chloride (PVC) sheet plasticised with di‐2‐ethyl hexyl phthalate (dioctyl phthalate, DOP), containing hydrocerussite 2PbCO3‐Pb(OH)2 stabiliser and milled with stearic acid lubricant, and which had been heated for various periods up to the Congo‐red test‐time at 180°C under N2, have been examined in reflection by X‐ray powder diffractometry. The penetration of X‐rays into these strips was rather low and so examination was confined to surface layers. Studies of the inorganic crystalline phases accord with results obtained during recent examinations of sections cut normal to the strip lengths (which represented the bulk materials) showing that the hydrocerussite reacted homogeneously throughout the hot samples and was completely used long before stabilisation failed at the Congo‐red test‐time. Surprisingly, crystalline salts of both orthophthalic and stearic acids were found in the surface regions, but not in the bulk. These results are interpreted in terms of a free‐radical chain mechanism for PVC decomposition and true stabilisation involving exchanges (which trapped chlorine free‐radicals) and temporary polymer esterifications (which inhibited release of chlorine free‐radicals from the PVC), with lead carboxylates being regenerated as the active intermediates. The inhomogeneous distributions for the lead salts of organic acids are then attributed to migration of intermediates towards the surfaces, combating potentially faster degradation than in the bulk (caused by oxidation of polymer in the surface regions when the newly milled PVC sheet was cooling to room temperature in air). It is concluded that true stabilisation involving lead compounds benefits PVC in commercial processes by retarding thermal decomposition and preventing the formation of HCl.
Synthesis of some new unsymmetrical aza‐pyrazolomonomethine cyanine dyes
Authors: El‐Kashef Hussein S. , El‐Shafei Ahmed K. , El‐Khawaga Ahmed M.
Published: July 2010

New aza‐pyrazolomonomethine cyanine dyes IV and V have been prepared by the condensation of some nitroso compounds, namely p‐nitroso‐N,N′‐dimethyl or diethyl aniline, α‐nitroso‐β‐naphthol and β‐nitroso‐α‐naphthoI, with known unsymmetrical pyrazolomonomethine cyanines II and III. The u.v. and visible spectra of all dyes prepared have been investigated.
Catalysed transformation of α‐pinene over platinum‐alumina
Authors: Krishnasamy Vengamuthu , Mathur Praveen , Chandrasekharan Kailasanathen
Published: July 2010

The transformations of α‐pinene have been investigated over platinum‐alumina containing varying amounts of platinum and platinum‐alumina modified with different amounts of Cs+ and F− in the temperature range 200–350°C. A study of the influence of contact time and temperature shows that α‐pinene isomerises via two parallel paths, one giving monocyclic products and the other giving rise to bi‐and tri‐cyclic compounds. Concentrations above 0.6% platinum have no beneficial effect. Impregnation of platinum‐alumina with F− increases the overall conversion of α‐pinene, enhances the disproportionation of menthadienes and decreases the formation of cymene. Conversely, Cs+ increases the formation of cymene, in spite of a reduction in the overall conversion of α‐pinene. Decrease of particle size was found to improve the overall activity of the catalyst. The activity of the catalyst remains almost constant for the overall conversion during the course of the run, but its dehydrogenating activity declines.
Effect of catalyst composition on the selectivity of competitive hydrogenations of mono‐olefinic reactants in the liquid state
Authors: Červený Libor , Kuncová Marcela , Vodová Barbora , Rüžička Vlastimil
Published: July 2010

The effect of the amount of platinum and the type of the carrier on the selectivity for competitive hydrogenation of 2‐methyl‐3‐butene‐2‐ol and hex‐l‐ene in methanol on platinum carrier catalysts has been studied. The effect of the type of the active component and carrier on the selectivity for competitive hydrogenation of 2‐methyl‐3‐butene‐2‐ol and 2‐phenylpropene in methanol and cyclohexane on various types of catalyst has also been investigated. Selectivity decreased with increasing amounts of platinum on the carrier and also with decreasing polarity of the carrier. The change in selectivity was greatest for a change in the active (metal) component of the catalysts; being in most cases several times higher in cyclohexane compared with methanol.
Production of furfural from agricultural wastes by using pressurised water in a batch reactor
Authors: Sharma Durlubh K. , Sahgal Prakash N.
Published: July 2010

Agricultural wastes such as rice husks and sawdust can be used for the manufacture of chemicals including furfural and acetic acid. In the present work the conventional use of superheated steam has been replaced by the use of superheated water in the acidic hydrolysis of rice husk and sawdust. Comparable yields of furfural have been obtained by using superheated water in place of superheated steam in the same temperature and pressure range. This is an attempt to economise the heat requirement and reduce the cost of production of furfural.
Optimal biofilm thickness for fluidised‐bed biofilm reactors
Authors: Kargi Fikret , Park Jung Keug
Published: July 2010

Fluidised‐bed biofilm reactors (FBFR) have been used extensively for the removal of BOD and nitrogen from wastewater. However, no attempt has been made to identify the optimal design of such reactors to maximise the rate of removal of waste substances. A theoretical analysis of FBFRs is presented and it is revealed that there is an optimal biofilm thickness for a given support particle size which maximises the volumetric removal rate of waste substance from the liquid stream.
Oxidation of ethanol over ferric molybdate catalyst
Authors: Srihari Voruganti , Viswanath Dabir S.
Published: July 2010

Oxidation of ethanol vapour over ferric molybdate catalyst in an isothermal flow reactor was investigated at 530–578 K and alcohol partial pressure range of 0.811–3.344 kPa. The rate data collected were well represented by a steady‐state two‐stage redox model conforming to an order of reaction of unity with respect to ethanol and 0.5 with respect to oxygen. Non‐linear least‐squares procedures gave a lower sum of squares of residuals in the estimation of the parameters of the rate equation compared with linear least‐squares methods. The activation energies for the first and second steps of the redox model were found to be 56.36 and 52.26 kJ mol−1 respectively.
Influence of the neutralising agent on jarosite precipitation
Authors: Ghodsi Mehdi , Detournay Jacquy , Marion Anne‐Marie
Published: July 2010

The study of the removal of iron from Zn electrolytic solutions by jarosite precipitation shows that it occurs irrespective of whether calcine or sinter is used. In both cases the iron residue has similar characteristics. Moreover it is clearly shown that the thermal treatment to which the calcine is submitted has a fundamental influence on the Zn loss in the ferruginous residue.
The utilisation of citrus waste as substrate for microbial protein production by the fungus Sporotrichum pulverulentum
Authors: Karapinar Mehmet , Okuyan Melahat
Published: July 2010

The growth and protein synthesis of Sporotrichum pulverulentum was studied in shake flask cultures using orange waste as carbon source. The influence of factors such as nitrogen source, initial pH, incubation time and temperature were investigated, ammonium sulphate being the best source of supplementary nitrogen. Biomass containing about 31.9% protein was obtained with a medium pH of 5.0 in 4 days incubation.
Desiccant characteristics of coconut pith
Authors: Idiculla Roschen , Seshadri S. K.
Published: July 2010

An experimental study has been made of the capacity, rate and efficiency of moisture adsorption by coconut pith. Regeneration characteristics at different temperatures have also been studied and its properties are compared with those of standard desiccants, especially silica gel. The results indicate that coconut pith shows good promise as a cheap, yet effective desiccant.
Homogeneous catalysis of the reduction of nitrobenzene by bromotris(triphenylphosphine) copper (I)
Authors: Datta Manik C. , Saha Chitta R. , Sen Debabrata
Published: July 2010

Homogeneous reduction of nitrobenzene by hydrogen in presence of complex [CuIBr(PPh3)3] as catalyst has been investigated. From a study of various operational parameters, it has been observed that maximum reduction occurred at 2.5 × 103 kPa pressure and at 473–513 K and resulted in 75% aniline, 10% azobenzene, 2% nitrosobenzene in ethanol, and 70% aniline, 5% azobenzene, 7% nitrosobenzene in dimethylformamide, calculated on the basis of input nitrobenzene. In an attempt to elucidate the reduction mechanism two new intermediates, [CuHPPh3Br]2 (I) and [(C6H5N=NC6H5)Cu2(PPh3)4Br2] (II), have been isolated and characterised by elemental analysis, spectral, thermal, magnetic and p.m.r. studies.
Synthesis of 2‐alkyl‐3‐methyl‐2‐cyclopentenones from carboxylic acids or methylketones
Authors: Fujita Tsutomu , Watanabe Shoji , Suga Kyoichi , Inaba Teruhiko
Published: July 2010

Various 2‐alkyl‐3‐methyl‐2‐cyclopentenones were prepared via 2‐alkyl‐4‐penten‐2‐ols serving as common intermediates from carboxylic acids or methylketones. For example, dihydrojasmone was prepared from heptanoic acid as follows: Grignard reaction of heptanoic acid (I) with allylmagnesium chloride gave 1‐decen‐4‐one (II) and re‐Grignard reaction of (II) with methylmagnesium iodide produced 4‐methyl‐1‐decen‐4‐ol (IV). 4‐Methyl‐1,4‐decanediol (V) was obtained by hydroboration of (IV). Oxidation of (V) with chromium trioxide gave 4‐hexyl‐4‐methyl‐4‐butanolide (VI). Dihydrojasmone may be prepared by dehydration of (VI) with polyphosphoric acid. Several new 2‐alkyl‐3‐methyl‐2‐cylopentenones were obtained by this method.
Some aspects of the chlorination of bauxite
Authors: Raval Rajesh P. , Dixit Sharad G.
Published: July 2010

Removal of iron and titanium impurities in bauxite by selective chlorination has been obtained by controlling the addition doses of coke and restricting the temperatures to below 323 K. The chlorination of iron and titanium free bauxite has been studied as regards the effect of coke addition, Cl2 flow rates and partial pressures and temperatures. The rate equation 1‐(1 ‐ R)1/3 = kt has been shown to fit the experimental data. It is concluded that the diatomic Cl2 molecule does not dissociate to atomic Cl during chlorination.
The preparation of pure L‐leucine. Separation of L‐leucine and L‐isoleucine
Authors: Hongo Chikara , Yoshioka Ryuzo , Yamada Shigeki , Chibata Ichiro
Published: July 2010

Existing methods for prepaiing pure L‐leucine from protein hydrolysates are unsatisfactory, especially when L‐leucine, isoleucine‐free, is required in high purity. Using a commercial crude leucine containing 73% of L‐leucine, 10% of L‐isoleucine and other impurities, the preparation of pure L‐leucine was investigated. As a result, the fractional crystallisation of the sulphonates of L‐leucine with benzenesulphonic acid and p‐toluenesulphonic acid was found to be very effective for the purification of L‐leucine. The pure L‐leucine in which no other amino acid was detected by an amino acid analyser was obtained by passing aqueous solutions of these sulphonates through ionic resin columns to separate L‐leucine and sulphonic acids. The overall yield of leucine was 59±62% of the theoretical. The present purification methods are considered to be very promising for the industrial production of L‐leucine from protein hydrolysates.
Solvent extraction in platinum group metal processing
Authors: Cleare Michael J. , Charlesworth Peter , Bryson David J.
Published: July 2010

This paper indicates the various ways in which the chemistry of the platinum group metals (PGM) can be manipulated to achieve separations using solvent extraction techniques and is not intended to be a comprehensive review of published work. Differences in the chemistry of PGM and base metals are emphasised as the latter are present in refinery liquors. Mechanisms of solvent extraction processes are discussed and related to PGM complex chemistry. Potential economic advantages for solvent extraction over conventional selective precipitation processes are considered.
The impact of solvent extraction and ion exchange on the hydrometallurgy of tungsten and molybdenum
Authors: Macinnis Martin B. , Kim Tai K.
Published: July 2010

This paper is concerned with the impact that solvent extraction and/or ion exchange has on the design of hydrometallurgical processes for the recovery of tungsten and molybdenum. The chemistries of tungsten and molybdenum will be discussed and flowsheets for the commercially important products will be presented.
Nitrogen containing additives in soda pulping of bagasse pith
Authors: Saad Saad Mohamed , Mohamed Hamdy A.
Published: July 2010

Unbleached soda pulp was prepared from Egyptian bagasse pith by varying the alkali concentration and the time of heating at the boiling point of the liquor under atmospheric pressure. A linear relationship was observed between the dissolved pith and the dissolved lignin. Pulping with alkali concentration higher than 10% but not exceeding 16% was more effective, since more delignification took place with lower dissolved pith percentage. p‐ And m‐nitrobenzoic acids and also hydroxylamine hydrochloride had a slight or no effect on the yield of the pulps. The alkali solubility percentage of the pulps prepared in the presence of any of the additives was lower than the control pulp. The delignification was enhanced more on the addition of hydroxylamine hydrochloride than p‐nitrobenzoic acid, while m‐nitrobenzoic acid seemed to have no effect. The yield of the pulps thus prepared, as determined by weighing, showed lower values than those determined by a chemical method. The soda delignification rate was shown to be proportional to the amount of unremoved lignin and the concentration of alkali in the liquor. The delignification reaction was found to follow approximately first‐order kinetics.
Separation of iron from manganese ore roast‐leach liquor
Authors: Sahoo Pravat K. , Das Sarat C. , Bose Subir K. , Sircar Sisir C.
Published: July 2010

The leach liquor obtained after the extraction of manganese from a low grade manganese ore contained both manganese and iron. In this paper an attempt has been made to remove iron by aerial oxidation. Parameters such as pH, temperature and time were varied in order to arrive at an optimum condition. It was observed that at a temperature of 333 K, pH 5.5 and aeration time of 2.25 h the iron could be completely removed at an air‐flow rate of 1000 cm3 min−1 without any loss of manganese.
Benzo(a)pyrene metabolites formed by the action of yeast cytochrome P‐450/P‐448
Authors: Wiseman Alan , Woods Leonard F. J.
Published: July 2010

Benzo(a)pyrene metabolites have been identified by high‐pressure liquid chromatography after production by a cytochrome P‐450 in brewer's yeast disruptates. The major metabolites are 7,8‐dihydro‐7,8‐dihydroxy‐benzo(a)pyrene, 9‐hydroxybenzo(a)‐pyrene and 3‐hydroxybenzo(a)pyrene. Pretreatment of the yeast with benzo(a)‐pyrene, during its growth decreases the Michaelis constant (Km) of the enzyme for benzo(a)pyrene, using either NADPH or cumene hydroperoxide as a cofactor.
Extraction of metals from sulphides using sulphur trioxide in fluidised bed
Authors: Ismail Mohamed I.
Published: July 2010

The kinetics of the reaction of chalcopyrite, iron sulphide, copper sulphide, and nickel sulphide with sulphur trioxide gas were studied using a fluidised bed technique. O2, N2, or air was used as a carrier gas for the sulphur trioxide in fluidisation. Binary mixtures of finely ground (0.37–75 μm) samples were reacted with the sulphur trioxide in a Pyrex column at 373–673 K. The reaction products were leached with water and the soluble metals in the solution were determined by atomic absorption spectrometry. The total soluble reaction products were determined gravimetrically. The results obtained showed that a higher yield of soluble salts was obtained when O2 or air was used as a carrier gas for sulphur trioxide than when an inert gas was used. Higher yields of soluble salts were obtained when the samples were most finely ground. Increase of copper sulphide content in binary mixtures with iron or nickel sulphide led to an increase in the yield of soluble salts. For iron sulphide/nickel sulphide mixtures, the yield of soluble salts increased with the nickel sulphide content. There were maximum values for the soluble metal ratios Ni/Fe and Cu/Ni in the corresponding sulphide binary mixtures and this maximum was at about 50% weight. The soluble Cu/Fe ratio increased with copper sulphide content in mixtures with iron sulphide.
Adsorption of phosphate ions by collodion‐coated alumina
Authors: Aharoni Chaim , Sideman Samuel , Hoffer Erica
Published: July 2010

The kinetics and the equilibrium adsorption of phosphate by collodion‐coated alumina granules were investigated. Collodion‐coated alumina can serve as a sorbent for phosphates in the treatment of hyperphosphatemic patients by haemoperfusion. The collodion coating lowers the surface area available for adsorption. The kinetics of adsorption were investigated by experiments in which the initial phosphate concentration, the quantity of sorbent and the grain size of sorbent were varied. The rate of adsorption is proportional to tα‐1 where t is time and α is around 0.7.
Analysis of microporosity and specific vapour sorption by zirconia gel
Authors: El‐Akkad Taghreed M.
Published: July 2010

The surface properties of zirconia gel and its thermal dehydration products obtained in the temperature range 300–1000°C (573–1273 K) were investigated through the adsorption of water, methanol and carbon tetrachloride vapours at 35°C (308 K). The non specific character of carbon tetrachloride makes it a good probe for detecting microporosity in the gel. Hydrophilic centres on the zirconia surface appear to function as favourable adsorption sites for polar water and methanol adsorbate molecule. The high values of the areas obtained from water adsorption for highly hydroxylated samples may be explained by the fact that the smaller polar water molecules can penetrate into narrow pores and interact with the hydroxyl groups located there. The presence of a high concentration of hydroxyl groups in the micropores is evident from the sharp decrease in the methanol uptake by zirconia gel, since methanol is known to interact specifically with hydroxyl groups existing in mesopores or on plane surfaces through hydrogen bonding.
A study of the anodic dissolution of gold in concentrated KCN solution
Authors: Pan Ting P. , Wan Chi Chao
Published: July 2010

The kinetics of anodic dissolution of gold in concentrated potassium cyanide solution was investigated. The mechanism was found to be magnified image with the second step being the rate determining step. Ultrasonic agitation increased the dissolution rate five‐fold. The mechanism however, remained unchanged. From current efficiency measurement, it was observed that no auric ions existed in the dissolution process.
Studies on the preparation of methyl bromide from sulphur, bromine and methyl alcohol
Authors: Bhavnagary Haiderali M. , Krishnamurthy Tirunillai S. , Majumder Suvendu K.
Published: July 2010

Optimum conditions have been presented for the production of methyl bromide by employing the reactants, sulphur, methyl alcohol, liquid bromine and water. For the maximum recovery of methyl bromide from liquid bromine used in the reaction, a 5% excess of sulphur and 30% excess of water than the stoichiometric quantities were found necessary. The addition of liquid bromine to the reaction mixture at slower rates of 0.5 to 2.5 cm3 min−1, reduced the loss of bromine as sulphur bromide and increased the yield of methyl bromide from 42 to 94.3%. With these standardised conditions, the product had a methyl bromide content of 98.2% with an overall yield of 94.42% based on liquid bromine.
Partial oxidation of methane to formaldehyde over halogen modified catalyst
Authors: Mann Ranvir S. , Dosi Mahendra K.
Published: July 2010

The partial oxidation of methane to formaldehyde over Pd‐supported on Al2O3 in the presence of small amounts of halogen modifiers was investigated in an isothermal integral flow reactor at atmospheric pressure between 300 and 510°C. The effects of several variables, feed ratio of air to methane, reaction temperature, reciprocal of space velocity, and the type and amount of halogen modifiers on the conversion and product distribution, were determined by gas chromatography. Though 13 different mechanisms were postulated the rate of reaction was most satisfactorily correlated by a mechanism which assumes the rate controlling step to be the surface reaction between charged, adsorbed methane and oxygen.
The role of additives in the impregnation of platinum and ruthenium on alumina catalysts
Authors: Aboul‐Gheit Ahmed Kadry
Published: July 2010

Platinum‐ and ruthenium‐alumina catalysts are prepared in the absence and presence of additives during metal impregnation. In the absence of additives, metal penetration and distribution in the support pellets is poor, whereas in the presence of a proper additive, uniform metal distribution can be achieved. The metal dispersion in the support is found to be a function of its distribution. In Pt/Al2O3, the addition of HCl improve the distribution and dispersion of the metal as its concentration increases. However, the use of monoethanolamine as an additive achieves an abrupt improvement in the distribution and dispersion of platinum, followed by a region of slight improvement (pH range 2.5–6.5). With a further increase in the concentration additive of the platinum distribution and dispersion deteriorates due to excessive metal penetration and accumulation in the centre of the pellet. In ruthenium preparations, citric acid appears to be the best additive. Oxalic acid also improves ruthenium impregnation but needs to be added in larger concentrations than citric acid. The hydrogenation activity of the catalysts reflected the improvement of the Pt and Ru distributions and dispersions in the support pellets.
Solubility of cobalt complex soaps using Co58 as radiotracer
Authors: Jain Ajay K. , Siddiqui Muzayan J. , Singh Ramesh P. B.
Published: July 2010

The solubility of cobalt dichloro tetrammine soaps in aqueous and non‐aqueous solvents has been determined by using Co58 as a tracer. The soaps have been found to be relatively more soluble when compared with simple cobalt soaps and cobalt hexammine soaps. The results are interpreted in terms of weaker polar interactions between the ionic groups of soaps. The solubility data in benzene, toluene and m‐xylene has also been used to calculate the critical solution temperature and critical micelle concentration values of the soaps. It has been found that the higher the solubility of the soap, the lower is its critical solution temperature and the higher is its critical micelle concentration in a solvent.
Electroreduction of lauronitrile and stearonitrile
Authors: Krishnan V. , Mahalingam N. , Udupa H. V. K.
Published: July 2010

Higher aliphatic amines are extensively used as wetting agents, corrosion inhibitors and as anti‐dusting agents. An electrochemical method for preparing laurylamine and stearylamine from their corresponding nitriles using nickel black cathode has been standardised in our laboratories. Both these nitriles underwent smooth reduction in ethanolic sulphuric acid medium to give a yield of around 80% amine for a current efficiency of 40–50%. Galvanostatic polarisation measurements indicated that the reduction is smooth only at lower current densities.
Direct measurement of microbial ATP in activated sludge samples
Authors: Kucnerowicz Felix , Verstraete Willy
Published: July 2010

A procedure is described to determine ATP directly (i.e. without separated extraction) in sludge samples. For a series of laboratory units, linear relationships were observed between their ATP‐contents and their respective cell residence times, loading rates, substrate removal and oxygen uptake rates. The potential use of ATP as a control parameter for activated sludge is discussed.
The effect of polymer structure on soil physico‐chemical properties and soil water evaporation
Authors: Callebaut Freddy , Gabriels Donald , Boodt Marcel De
Published: July 2010

The effect of water‐soluble polymers and polymer emulsions upon the physico‐chemical properties of silt‐loam aggregates has been tested. The efficiency of soluble polymers depends on their concentration and molecular weight. Polymer emulsions induce hydrophobocity of soil surfaces. Waste lignosulphonates appear attractive at reducing soil water evaporation.
Hydrolysis of aromatic sulphonic acids in industrial effluents. II. Hydrolysis of amido‐J‐acid
Authors: Rossinelli Luca , Thies Hans , Richarz Werner
Published: July 2010

The kinetics of the acid‐catalysed hydrolysis of 6‐amino‐1,3‐naphthalenedisulphonic acid (amido‐J‐acid) were measured at temperatures of 533–573 K. The only product of the reaction is 2‐naphthol, the amino group being hydrolysed much faster than both sulpho groups. The hydrolysis can be described kinetically as a two‐step consecutive reaction. Rate constants and activation parameters were determined.
Electronic absorption spectra and acid—base equilibria of some arylaminoanthraquinones in aqueous medium
Authors: Idriss Kamal A. , Seleim Mohamed M.
Published: July 2010

The visible absorption spectra of 1,4‐di‐(4′‐methylanilino)anthraquinone (Alizarin Cyanin Green) and its disulphonated derivative (Quinizarin Green); 7,8‐dihydroxy‐1,4‐di‐(2′‐sulpho‐4′‐methylanilino)anthraquinone (Alizarin Viridine); 1‐hydroxy‐4(2′‐sulpho‐4′‐methylanilino)anthraquinone (Alizarin Irisol R) and 1,4‐dihydroxy‐2‐(2′‐sulpho‐4′‐methylanilino)anthraquinone (Alizarin Heliotrope) have been recorded in aqueous solutions at different pH values. The spectral changes are explained in terms of shifts in equilibria between different molecular and ionic species in the solutions. The pKa values have been determined for different acid‐base equilibria and discussed in relation to molecular structure. Release of a proton from the NH‐group in 1,4‐bis(arylamino) derivatives is liable to occur through mesomeric interaction between the imino‐nitrogen and CO group. The mesomeric shift is influenced by the pH of solution as well as the nature of compound.
The fate of carbon compounds in the landfill disposal of organic matter
Authors: Rees John F.
Published: July 2010

Landfill sites containing domestic refuse should be managed so as to optimise methane production when hydrogeological conditions permit. On large sites this would be both economically profitable and environmentally desirable as uncontrolled pollution would be minimised and sites could be reclaimed as quickly as possible. Landfill microbiology has been confined to public health aspects, and clearly, further microbiological studies are required to optimise the degradation of carbon compounds. Knowledge of the fate of synthetic polymers is poor. It is interesting to consider whether they constitute a reservoir of delayed‐potential methane generation. Contrary to previous ideas it is concluded that there is no requirement for added nitrogen and phosphorus sources. The interaction of refuse density and water content is identified as a major factor which must be controlled to optimise methane generation. The high solids content and reactivity of this anaerobic bioreactor coupled with the poor thermal conductivity of refuse enables the landfill to generate and sustain high temperatures. The roles of refuse pretreatment, placement methods and water management techniques in the control and stimulation of refuse fermentation are also discussed.
The precipitation and some properties of alumina coatings on rutile
Authors: Cornell Rochelle M. , Posner Alan M. , Quirk James P.
Published: July 2010

Alumina was precipitated on to rutile in four different ways to provide a series of alumina‐coated rutiles. There were two main types of precipitate. Type A with alumina precipitated in an acid medium and type B with alumina precipitated at pH 8. The two types of coating differed in appearance, surface area and in the nature of alumina present. For the type A coatings, the precipitate was irregular with much interstitial material and consisted of amorphous alumina of surface area < 100 m2 g−1. The type B coatings were compact and almost invisible and had surface areas > 140 m2 g−1. Alumina gels were precipitated under similar conditions to the type A and type B coatings and compared with these coatings to see if the presence of rutile had modified the type of alumina that formed.
Solid‐liquid separation after liquid‐liquid extraction. Spectrophotometric determination of cobalt by extraction of its thioxanthate complex with molten naphthalene
Authors: Puri Bal K. , Gautam Mamta
Published: July 2010

Optimum conditions have been developed for the extraction of cobalt thioxanthate by solid‐liquid separation after liquid‐liquid extraction.
Kinetics and diffusion processes in colour removal from effluent using wood as an adsorbent
Authors: McKay Gordon , Poots Victor J. P.
Published: July 2010

The rates of adsorption of a basic dye, Astrazone Blue, and an acidic dye, Telon Blue, on wood have been studied. The rate controlling step is mainly intraparticle diffusion, although a small resistance due to a boundary layer is experienced. The activation energies for the adsorption of Astrazone Blue and Telon Blue on wood are 16.8 kJ mol−1 and 9.6 kJ mol−1, respectively. The diffusion coefficients vary from 6×10−13 cm2 s−1 to 18×10−13 cm2 s−1 for Astrazone Blue at 18°C and from 3 × 10−13 cm2 s−1 to 8 × 10−13 cm2 s−1 for Telon Blue at 18°C. The variation in diffusivities is attributed to boundary layer effects.
Production of aromatic acids during anaerobic digestion of citrus peel
Authors: Lane Alan G.
Published: July 2010

Commercially prepared citrus oils, distilled citrus oils, limonene and the non‐volatile fraction of lemon oils were all found to be toxic to the anaerobic digestion process for conversion of citrus waste to methane. Toxicity was characterised by appearance of benzoic, phenylacetic and phenylpropionic acids in the digestion liquors, though these acids were not in themselves toxic. The bulk of the phenylpropionic acid was derived from flavonoids.